KR20180058308A - Transparent liquid crystal display - Google Patents

Abstract

Provided is a transparent liquid crystal display device which operates by distinguishing when a display image is driven and when the display image is just transmitted. The transparent liquid crystal display device comprises a liquid crystal panel; a light guide plate disposed on a lower portion of the liquid crystal panel; an LED assembly for providing light from the side of the light guide plate; an upper AR film formed on the upper surface of the light guide plate and refracting light incident from the light guide plate to the liquid crystal panel; a lower AR film formed on the lower surface of the light guide plate and reflecting the light incident from the light guide plate to the liquid crystal panel; and a transparent glass plate disposed on a lower portion of the light guide plate, wherein when observed from the upper side of the liquid crystal panel, an image of the liquid crystal panel is recognized if the LED assembly is turned on and a subject disposed on a lower portion of the transparent glass substrate is recognized if the LED assembly is turned off.

Description

[0001] Transparent liquid crystal display [0002]

More specifically, the present invention relates to a transparent liquid crystal display, more particularly, to a liquid crystal display device which is divided into a liquid crystal panel and a liquid crystal panel when the liquid crystal panel is not driven, And more particularly, to a transparent liquid crystal display device capable of increasing visibility of an image displayed on a liquid crystal panel by increasing brightness when the panel is driven.

A transparent liquid crystal display generally refers to a display in which a backlight unit is removed from a general liquid crystal display device and sunlight or light in a real life is used as a light source. As a typical example, there is a box-type transparent liquid crystal display device in which a product to be advertised is placed in a box-shaped show window, and a transparent liquid crystal display device is installed in a show window. When light is illuminated inside the boxed display, customers can watch the images, images, or texts displayed on the transparent liquid crystal display while viewing the products placed in the show window.

Such a box-type transparent liquid crystal display device uses a separate light source as a light source instead of the backlight unit, because the distance between the liquid crystal panel and the illumination is long, so that the intensity of light transmitted through the liquid crystal panel is weak and the luminance is low. In addition, the box-type transparent liquid crystal display device is disadvantageous in that the operation is not divided according to whether the liquid crystal panel is driven or not, but images and products of the liquid crystal panel are overlapped with each other by the same illumination simultaneously illuminating the liquid crystal panel and the product, . Furthermore, it is difficult to apply the box-type transparent liquid crystal display device to an environment where it is difficult to install light, for example, a safety door of a subway platform.

The object of the present invention is to distinguish between when the display image is driven and when only the transmissive display is turned on, and when the LED assembly is turned off, the transmissivity is increased so that the object disposed behind the liquid crystal panel can be well recognized, When the liquid crystal display panel is turned on, the brightness of the liquid crystal panel is increased to visually recognize the image displayed on the liquid crystal panel.

The problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a transparent liquid crystal display device including: a liquid crystal panel; A light guide plate disposed below the liquid crystal panel; An LED assembly for providing light at a side of the light guide plate; An upper AR film formed on the upper surface of the light guide plate and refracting the light incident from the light guide plate to the liquid crystal panel; A lower AR film formed on the lower surface of the light guide plate and reflecting the light incident from the light guide plate to the liquid crystal panel; And a transparent glass plate disposed under the light guide plate. Here, when observing from above the liquid crystal panel, an image of the liquid crystal panel is viewed when the LED assembly is in an ON state. When the LED assembly is in an OFF state, The subject is viewed.

The upper and lower surfaces of the light guide plate may be flat.

The upper AR film includes a pressure sensitive adhesive layer, a base film, a hard coating layer, an antireflection layer, and a protective film sequentially stacked on the upper surface of the light guide plate. The hard coating layer has a refractive index higher than that of the base film, And may be refracted at the boundary between the hard coating layer and the base film.

Wherein the lower AR film comprises a pressure sensitive adhesive layer, a base film, a hard coating layer, an antireflection layer, and a protective film sequentially laminated on a lower surface of the light guide plate, wherein the hard coating layer has a refractive index higher than that of the antireflection layer, May be totally reflected toward the light guide plate at the boundary between the hard coating layer and the antireflection layer.

It is preferable that no optical sheet is interposed between the upper AR film and the liquid crystal panel.

It is preferable that no optical sheet is interposed between the lower AR film and the transparent glass plate.

The details of other embodiments are included in the detailed description and drawings.

As described above, the transparent liquid crystal display according to the present invention has the following remarkable effects.

According to the present invention, the transmissivity of the transparent liquid crystal display device itself is increased so that the subject disposed behind the transparent liquid crystal display device can be well recognized when the LED assembly is in the off state. For this purpose, first, a light guide plate having no pattern on its surface was used. Generally, a pattern is formed on the surface of a general light guide plate to improve uniformity of light and increase brightness. Since the light guide plate itself is made of a high transmittance material, the light incident on the side of the light guide plate is smoothly transmitted along the longitudinal direction (or the horizontal direction) of the light guide plate. However, when a pattern is formed on the surface of the light guide plate, the surface of the light guide plate is puddled or fogged, so that the transmittance of the light guide plate significantly decreases in the thickness direction (or up and down direction). On the contrary, in the case of the transparent liquid crystal display device of the present invention, since the light guide plate is formed as a flat surface and there is no pattern on the surface, the subject disposed behind the transparent liquid crystal display device can be recognized well with the LED assembly off. Second, by removing a general optical sheet between the liquid crystal panel and the light guide plate, the transmittance of the transparent liquid crystal display device of the present invention is increased as a whole. In a typical liquid crystal display device, a plurality of optical sheets (e.g., a diffusion sheet, a prism sheet, etc.) are disposed between a light guide plate and a liquid crystal panel in order to diffuse and condense light transmitted from a light guide plate. Since these optical sheets act as a factor for hindering the transmittance of the transparent liquid crystal display device, these optical sheets are excluded in the present invention.

According to the present invention, AR films are formed on both sides of the light guide plate to increase the brightness of the liquid crystal panel when the LED assembly is in an on state. Specifically, since there is no pattern on the surface of the light guide plate of the present invention, the lowering of the luminance may be a problem. To overcome this problem, the upper AR film is formed on the upper surface of the light guide plate and the lower AR film is formed on the lower surface thereof. In particular, the upper AR film refracts light incident on the light guide plate toward the liquid crystal panel, and the lower AR film totally reflects at least a part of the light incident backward from the light guide plate to direct the light toward the liquid crystal panel. The light is constantly reflected and refracted in the light guide plate by the upper AR film and the lower AR film, so that the light straightness and uniformity can be obtained.

As described above, the transparent liquid crystal display of the present invention can increase the transmittance of the entire display device when transmitting only the display image, thereby enhancing the discrimination power of the rear subject, and enhancing the visibility of the image by increasing the brightness of the liquid crystal panel when driving the display image . For example, when the transparent liquid crystal display device of the present invention is installed in a safety door of a subway platform, it is possible to drive a display image such as an advertisement on a liquid crystal panel while the subway is not in the platform, So that a safety accident can be prevented.

1 is an exploded perspective view of a transparent liquid crystal display according to an embodiment of the present invention.
FIG. 2A is a cross-sectional view of the transparent liquid crystal display device of FIG. 1 taken along the line AA ', when the display image is driven.
FIG. 2B is a cross-sectional view of the transparent liquid crystal display device of FIG. 1 taken along line AA '.
FIG. 3 is a cross-sectional view showing the structure of the upper AR film, the light guide plate and the lower AR film in FIG. 1 in detail.
FIG. 4 is a cross-sectional view showing the refraction of light in the upper AR film of FIG. 3; FIG.
FIG. 5 is a cross-sectional view showing reflection of light in the lower AR film of FIG. 3. FIG.
FIG. 6 shows a comparison between the ON state and the OFF state of the liquid crystal panel when the transparent liquid crystal display of the present invention is actually implemented.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

It is to be understood that when an element or layer is referred to as being "on" or " on "of another element or layer, All included. On the other hand, a device being referred to as "directly on" or "directly above " indicates that no other device or layer is interposed in between. Like reference numerals refer to like elements throughout the specification. "And / or" include each and every combination of one or more of the mentioned items.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation.

Embodiments described herein will be described with reference to plan views and cross-sectional views, which are ideal schematics of the present invention. Thus, the shape of the illustrations may be modified by manufacturing techniques and / or tolerances. Accordingly, the embodiments of the present invention are not limited to the specific forms shown, but also include changes in the shapes that are generated according to the manufacturing process. Thus, the regions illustrated in the figures have schematic attributes, and the shapes of the regions illustrated in the figures are intended to illustrate specific types of regions of the elements and are not intended to limit the scope of the invention.

Hereinafter, a transparent LCD according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view of a transparent liquid crystal display device according to an embodiment of the present invention. FIG. 2A is a cross-sectional view of the transparent liquid crystal display device of FIG. 1 taken along line AA ' FIG. 3 is a cross-sectional view showing the structure of the upper AR film, the LGP, and the lower AR film of FIG. 1 in detail. FIG. 3 is a cross-sectional view of the transparent liquid crystal display of FIG.

The transparent liquid crystal display device 10 of the present invention includes the upper case 110, the liquid crystal panel assemblies 120, 122 and 124, the backlight assemblies 130, 140, 230, 170 and 172, the lower case 150, And a transparent glass plate 160.

The liquid crystal panel assemblies 120, 122 and 124 include a liquid crystal panel 120, a chip film package 124, and a printed circuit board 122 and the like.

The liquid crystal panel 120 includes a lower display panel including a gate line, a data line, a thin film transistor array, and a pixel electrode, an upper display panel disposed to face the lower display panel, and a liquid crystal layer interposed between the two display panels. The liquid crystal panel 120 serves to display image information. Although not shown, a known polarizing film is attached to both sides of the liquid crystal panel 120. [

The chip film package 124 is connected to each data line formed on the lower panel to provide a data driving signal. The chip film package 124 may include a TAB tape that is bonded to a wiring pattern formed on a flexible film by a TAB (Tape Automated Bonding) technique. For example, a tape carrier package (TCP) or a chip on film (COF) may be used as the chip film package. However, the above-mentioned chip film package is merely an example.

The gate driver is connected to each gate line formed in the lower panel to provide a gate driving signal, and may be formed in the form of an integrated circuit on the lower panel. That is, in the process of manufacturing the thin film transistor array. However, the present invention is not limited thereto and may be formed in the same shape as the chip film package 124.

On the other hand, in the printed circuit board 122, a plurality of driving parts for processing the gate driving signal inputted to the gate driving part and the data driving signal inputted to the chip film package 124 are mounted. In other words, the printed circuit board 122 is connected to the liquid crystal panel 120 to provide image information. Since the printed circuit board 122 is connected to the liquid crystal panel 120 by the chip film package 124 made of a flexible film, the printed circuit board 122 can be folded along one side of the liquid crystal panel 120 and housed in the case.

The backlight assembly 130 includes an upper anti-reflection film 130, a light guide plate 140, a lower anti-reflection film 230, and LED assemblies 170 and 172. And the like.

Here, the light guide plate 140 guides light supplied from the LED assemblies 170 and 172 to the liquid crystal panel 120. The light guide plate 140 is a plate made of a plastic-based transparent material. For example, acrylic resin such as PMMA (PolyMethyl Methacrylate) or polycarbonate may be used as the light guide plate 140. The upper surface and the lower surface of the light guide plate 140 are formed as flat surfaces, and no pattern is formed. When the diffusion pattern is formed on the surface of the light guide plate 140, the surface of the light guide plate 140 is puddled or blurred to reduce the transmittance in the thickness direction of the light guide plate 140 (vertical direction in FIG. 2B) It becomes difficult to identify the subject. Accordingly, in the present invention, the upper and lower surfaces of the light guide plate 140 are formed as flat surfaces in order to increase the discrimination power of the rear subject in the OFF state of the LED assemblies 170 and 172, thereby increasing the total transmittance of the transparent liquid crystal display device 10 .

LED assemblies 170 and 172 are disposed on the side of the light guide plate 140. The LED assemblies 170 and 172 are provided on the long side and the short side of the light guide plate 140. However, the present invention is not limited thereto, and the LED assembly 170 , 172 can be adjusted.

The upper AR film 130 is formed on the upper surface of the light guide plate 140. The upper AR film 130 may be coated on the light guide plate 140 by, for example, a laminating method. As another example, the upper AR film 130 may be formed on the upper surface of the light guide plate 140 through a thin film deposition process. For convenience of explanation, the upper AR film 130 formed by the laminating method will be described. The upper AR film 130 has layers having different refractive indexes and serves to increase the brightness by refracting the light incident from the light guide plate 140 to the liquid crystal panel 120 using the difference in refractive index. The operation of the upper AR film 130 will be described in detail with reference to FIGS. 3 and 4. FIG. 4 is a cross-sectional view showing the refraction of light in the upper AR film of FIG.

The upper AR film 130 includes a pressure sensitive adhesive layer 131, a base film 132, a hard coating layer 133, an antireflection layer 134, and a protective film 135 sequentially stacked on the upper surface of the light guide plate 140 . The pressure sensitive adhesive layer 131 serves to attach the upper AR film 130 to the light guide plate 140. For example, PSA (Pressure Sensitive Adhesive) may be used. If the upper AR film 130 is formed by a thin film deposition process, the pressure-sensitive adhesive layer 131 may be omitted. The base film 132 protects the hard coating layer 133 and the antireflection layer 134. For example, TAC (Tri Acetate Cellulose) can be used. The hard coating layer 133 is made of a material having a refractive index higher than that of the base film 132, and may be made of, for example, a TiO ₂ -based material. The antireflection layer 134 serves to reduce the reflectance of direct reflection of external light, and may be made of, for example, a SiO ₂ -based material. The protective film 135 protects the upper AR film 130 from an external scratch or the like and may be made of, for example, PE (polyethylene).

Since the LED assemblies 170 and 172 are disposed on the side of the light guide plate 140, light emitted from the light guide plate 140 has a relatively large incident angle. If the angle of incidence is large, the light may escape to the periphery, which may cause a luminance drop due to light loss. Thus, in the present invention, the upper AR film 130 is formed on the upper surface of the light guide plate 140 to minimize light loss. That is, by utilizing the refractive index difference between the base film 132 and the hard coat layer 133 constituting the upper AR film 130, the light exit angle of light incident from the light guide plate 140 is reduced, So that light is directed to the liquid crystal panel 120. 4, the base film 132 has a relatively low refractive index and the hard coating layer 133 has a relatively high refractive index. According to Snell's law, light incident from the light guide plate 140 at a large incident angle is refracted at a small emitting angle at the boundary between the base film 132 and the hard coat layer 133. That is, a lot of light is refracted toward the liquid crystal panel 120 more. This may lead to an increase in luminance of the liquid crystal panel 120, thereby enhancing the image visibility on the liquid crystal panel 120. [

On the other hand, a lower AR film 230 is formed on the lower surface of the light guide plate 140. The lower AR film 230 may be coated on the light guide plate 140 by, for example, a laminating method. As another example, the lower AR film 230 may be formed on the lower surface of the light guide plate 140 through a thin film deposition process. For convenience of explanation, the lower AR film 230 formed by the laminating method will be described. The lower AR film 230 has layers having different refractive indexes. Using the difference in refractive index, the lower AR film 230 totally reflects the light incident from the light guide plate 140 to the light guide plate 140 to increase the brightness. Hereinafter, the operation of the lower AR film 230 will be described in detail with reference to FIGS. 3 and 5. FIG. 5 is a cross-sectional view showing reflection of light in the lower AR film of FIG.

The lower AR film 230 includes a pressure sensitive adhesive layer 231, a base film 232, a hard coat layer 233, an antireflection layer 234, and a protective film 235 sequentially stacked on the lower surface of the light guide plate 140 . The lower AR film 230 has a symmetrical structure with the upper AR film 130 with respect to the light guide plate 140. The pressure sensitive adhesive layer 231 serves to attach the lower AR film 230 to the light guide plate 140. For example, PSA (Pressure Sensitive Adhesive) may be used. If the lower AR film 230 is formed by a thin film deposition process, the pressure-sensitive adhesive layer 231 may be excluded. The base film 232 protects the hard coating layer 233 and the antireflection layer 234, for example, TAC (Tri Acetate Cellulose) or the like can be used. The hard coat layer 233 is made of a material having a predetermined hardness, and may be made of, for example, a TiO ₂ -based material. The antireflection layer 234 is made of a material having a refractive index lower than that of the hard coating layer 233, and may be made of, for example, a SiO ₂ -based material. The protective film 235 protects the lower AR film 230 from an external scratch or the like, and may be made of, for example, PE (polyethylene).

The light incident on the light guide plate 140 from the LED assemblies 170 and 172 may escape to the outside through the lower surface of the light guide plate 140. In this case, AR film 230 is formed to minimize light loss. That is, at least a part of the light incident from the light guide plate 140 is totally reflected by the light guide plate 140 using the refractive index difference between the hard coating layer 233 and the antireflection layer 234 constituting the lower AR film 230. Generally, total reflection is a phenomenon in which light is totally reflected at a boundary when a light is incident at an angle of more than a critical angle from a medium having a large refractive index to a medium having a small refractive index. 5, since the hard coating layer 233 is made of a material having a refractive index higher than that of the antireflection layer 234, when the light incident from the light guide plate 140 is incident at an incident angle exceeding the critical angle, the hard coating layer 233, The total reflection occurs at the interface of the light guide plate 234 and enters the light guide plate 140 again. That is, the light that is lost to the lower portion of the light guide plate 140 can be minimized, and the brightness of the liquid crystal panel 120 can be increased.

The upper case 110 and the lower case 150 are coupled to each other to house the liquid crystal panel assemblies 120, 122 and 124 and the backlight assemblies 130, 140, 230, 170 and 172 therein. A transparent glass plate 160 is disposed under the lower case 150 and an object to be transmitted is located below the transparent glass plate 160.

In the present invention, no optical sheet is interposed between the upper AR film 130 and the liquid crystal panel 120 to increase the transmittance when the transparent liquid crystal display device 10 is in the off state, It is preferable that no optical sheet is interposed between the glass plates 160.

FIG. 6 shows a comparison between the ON state and the OFF state of the liquid crystal panel when the transparent liquid crystal display of the present invention is actually implemented. For example, the transparent liquid crystal display device of the present invention is implemented as a safety gate for a subway platform.

When the liquid crystal panel is on (FIG. 6A), the brightness of the liquid crystal panel is high, so that the image on the panel can be accurately viewed, and further, the rearward object is hardly recognized. Further, when the liquid crystal panel is in the off state (Fig. 6B), the transmittance of the entire display device is high, so that the rearward object can be well recognized.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

10: Transparent liquid crystal display
110: upper case
120: liquid crystal panel
122: printed circuit board
124: Chip film package
130: upper AR film
131: pressure-sensitive adhesive layer
132: base film
133; Hard coating layer
134: antireflection layer
135: Protective film
140: light guide plate
150: Lower case
160: Transparent glass plate
170, 172: LED assembly
230: Lower AR film
231: pressure-sensitive adhesive layer
232: base film
233; Hard coating layer
234: antireflection layer
235: Protective film

Claims (6)

A liquid crystal panel;
A light guide plate disposed below the liquid crystal panel;
An LED assembly for providing light at a side of the light guide plate;
An upper AR film formed on the upper surface of the light guide plate and refracting the light incident from the light guide plate to the liquid crystal panel;
A lower AR film formed on the lower surface of the light guide plate and reflecting the light incident from the light guide plate to the liquid crystal panel; And
And a transparent glass plate disposed below the light guide plate,
When the LED assembly is in an ON state, an image of the liquid crystal panel is visually observed. When the LED assembly is in an OFF state, a subject disposed at a lower portion of the transparent glass substrate The transparent liquid crystal display device comprising: The method according to claim 1,
Wherein the upper and lower surfaces of the light guide plate are flat. The method according to claim 1,
Wherein the upper AR film comprises a pressure sensitive adhesive layer, a base film, a hard coating layer, an antireflection layer, and a protective film which are sequentially laminated on the upper surface of the light guide plate. The method of claim 3,
Wherein the hard coating layer has a refractive index higher than that of the base film so that light incident from the light guide plate is refracted at a boundary between the hard coating layer and the base film. The method according to claim 1,
Wherein the lower AR film comprises a pressure-sensitive adhesive layer, a base film, a hard coating layer, an antireflection layer, and a protective film sequentially laminated on the lower surface of the light guide plate. 6. The method of claim 5,
Wherein the hard coating layer has a refractive index higher than that of the antireflection layer so that light incident from the light guide plate is totally reflected toward the light guide plate at a boundary between the hard coating layer and the antireflection layer.

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