KR101187748B1 - Edge type back light unit without light guide plate and display apparatus using the same - Google Patents

Abstract

PURPOSE: An edge type backlight unit without a light guide plate and a display device thereof are provided to freely adjust waveguide of light and uniformity of emitted light by a micro optical sheet without using a light guide plate for guiding light in a side light irradiating display. CONSTITUTION: An upper optical sheet(130) provides light to a display panel. A lower optical sheet(140) is separated from the upper optical sheet. A scattered reflection pattern is formed on the frontal side of the lower optical sheet. A reflection sheet is formed on a rear side of the lower optical sheet. The reflection sheet reflects light, which is leaked from the lower optical sheet, to a light emitting side.

Description

Edge Type Back Light Unit without Light Guide Plate and Display Apparatus Using the Same}

The present invention relates to a non-light guide plate edge type backlight unit and a display device employing the same, and more particularly, by omitting the light guide plate while maintaining the uniformity of the light irradiated from the LED light source located on the side, to the LCD panel side, the product price competitiveness It relates to a light guide plate edge type backlight unit that can increase the height, and to configure the product more slim, and a display device employing the same.

Due to the popularization of LED (LED) devices, the application of LEDs as light sources to TVs, monitors, mobile displays, tablet PCs, etc. is gradually increasing.

In addition, with the increasing market of display systems such as display advertising panels, promotional panels, display panels, etc., there is an increasing demand for cheaper display systems.

LED has advantages such as long life, wide operating temperature range, fast response time, environmentally friendly and high color reproducibility compared to CCFL (Cold Cathode Fluorescent Lamp) which is widely used as a light source of a conventional backlight unit. In addition, there is an advantage that it is possible to illuminate the light of a high luminance depending on the structure.

However, the key point for the LED CCFL replacement is that the manufacturing cost for manufacturing the LED Back Light Unit is lowered to the level of replacing the CCFL.

The most commonly used display system is a back illumination display, where a light source for irradiation is present on the back of the panel, and for a large size, several light sources are used to enable irradiation while maintaining uniformity.

However, such a back-illumination display has a disadvantage in that it is difficult to maintain uniformity even in a large or small size. As the size of the panel increases, the number of LED light sources increases, the power consumption thereof increases, and the entire system is opened and closed during maintenance. There is a difficulty for this.

In addition, since it is possible to maintain uniformity only by keeping the distance between the light source and the display surface, slimming of the panel becomes impossible.

As a method for realizing uniform irradiation in the construction of a display system, there have been attempts to achieve uniform irradiation by adjusting the transmittance of an image object to be irradiated while using a uniform dot shape in which the shape does not change. In the same system, it is difficult to arbitrarily adjust the transmittance of the image of the object to be irradiated.

On the other hand, the side irradiation display is a light source for irradiation is present on the side of the panel, the light guide plate for the optical waveguide in the light source should be provided.

Korean Patent No. 10-708461 relates to a light-emitting backlight unit having a multi-chip light emitting diode package and a display device employing the light-emitting diode package, and has disclosed a light-emitting backlight unit capable of compacting by reducing mixed color space.

However, since the light guide plate needs to be used for light waveguide in the light source, the conventional technology has a limitation in slimming the overall thickness of the backlight unit, and there is still a problem that the demand for thinning the backlight unit is not satisfied.

The present invention has been made to solve the above problems, without using a light guide plate for the optical waveguide in the side irradiation display, the edge type that can freely adjust the uniformity of the waveguide and the outgoing light of the light through the microstructured optical sheet Its purpose is to provide a backlight unit.

In addition, the object of the present invention is to provide an edge-type backlight unit that can be made lighter and thinner by making the entire backlight unit slim by not using a light guide plate.

In addition, it is an object of the present invention to provide an edge type backlight unit that can significantly reduce the manufacturing cost of the backlight unit by not using a light guide plate, which can greatly enhance the price competitiveness.

In addition, an object of the present invention is to provide a display device employing an edge type backlight unit which is inexpensive to manufacture and which is light in weight and thin.

In order to achieve the above object, in the present invention, the light source is installed on one side of the display panel to generate light, and the prism in the direction perpendicular to the light source to guide the light emitted from the light source from the light incident portion to the light portion; An upper optical sheet formed on one surface to provide the light to the display panel, and a lower optical sheet installed at a predetermined distance from the upper optical sheet and having a scattering reflection pattern formed on one surface, and not using a light guide plate. Type backlight unit is provided.

The upper optical sheet may have the prism formed on the light exit surface.

In the present invention, the prism may be composed of an isosceles prism symmetrical or non-symmetrical about the axis of symmetry.

In addition, the prism may be composed of a quarter prism in which a certain amount of total internal reflection occurs and the rest allows forced transmission.

Here, the prism may be made of any one selected from a transparent polymer material PMMA, PC, PET, UV curable resin.

In another embodiment of the present invention, the prism may be configured in the shape of an R-prism or a lenticular pattern.

In the present invention, the scattering reflection pattern is formed on the front surface of the lower optical sheet, the density may increase from the light incident to the light portion may be configured to maintain the light uniformity.

The scattering reflection pattern may be opaque or translucent.

The scattering reflection pattern may be formed of any one selected from a combination of a dot shape, a stripe shape, a dot, and a stripe shape.

Here, the stripe shape of the scattered reflection pattern is arranged to be parallel to the light source, the density of the stripe shape of the same area can be densified or the area of the stripe shape can be increased at the same interval.

In addition, the dot shape of the scattered reflection pattern may increase the density by increasing or decreasing the interval between the dots or the area of the dots.

The scattering reflection pattern may be molded by any one of screen printing, etching, painting, sanding, and injection molding.

In another embodiment of the present invention, in order to achieve the above object, a light source installed on one side of the display panel to generate light, and the light source for guiding light emitted from the light source from the light incident portion to the light portion; A prism in a vertical direction is formed on one surface of the upper optical sheet for providing the light to the display panel, and is spaced apart from the upper optical sheet by a predetermined distance, and uniformly emits light emitted from the light source to the display panel. Provided is an edge type backlight unit including a lower optical sheet having a prismatic structure for irradiating lightly.

Here, the reflective surface of the lower optical sheet has a shape of a micro structure that is adjusted as the angle moves from the light incident portion to the light facing portion. The shape of the micro structure has a Fresnel shape in which the angle increases as it moves from the light incidence part to the light part, thereby improving the uniformity of light emitted from the backlight unit and incident on the LCD panel.

In detail, the reflective surface of the lower optical sheet may have a prism shape having a small inclination angle close to the smooth surface in the light incident portion, and may have a structure in which the prism angle increases as the light guide portion moves.

In the present invention, a rear surface of the lower optical sheet may further include a reflective sheet reflecting light leaking from the lower optical sheet toward the light exit surface.

In addition, the light source may be composed of a plurality of LEDs.

On the other hand, in order to achieve the above object, the display device provided in the present invention may include a display panel and the edge type backlight unit as described above for irradiating light to the display panel.

As described above, the edge type backlight unit of the present invention does not use the light guide plate for the optical waveguide, and freely adjusts the waveguide and the uniformity of the emitted light through the microstructured optical sheet, thereby reducing the weight and thickness of the entire backlight unit. There are advantages to it.

In addition, by not using the light guide plate, the manufacturing cost of the backlight unit can be drastically reduced, thereby greatly enhancing the price competitiveness of the backlight unit and the display device employing the same.

1 is a perspective view showing a first embodiment of a display device of the present invention.
FIG. 2 is a cross-sectional view for showing the configuration of the optical sheet in FIG. 1.
3A to 3C are cross-sectional views illustrating embodiments of the upper optical sheet of the present invention and showing various prismatic shapes.
4A to 4B are perspective views illustrating embodiments of the lower optical sheet of the present invention.
5 is a perspective view showing a second embodiment of the display device of the present invention.
6 is a cross-sectional view in FIG. 5.
7A is a cross-sectional view showing a light incident part of the lower optical sheet in the second embodiment of the present invention.
FIG. 7B is a cross-sectional view showing a light portion of a lower optical sheet in a second embodiment of the present invention. FIG.
FIG. 8 is a cross-sectional view illustrating a prismatic structure of a lower optical sheet in a second exemplary embodiment of the present invention.
9 to 10 are graphs for explaining the configuration of the third embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Also, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and shall not be construed in an overly formal sense unless explicitly defined in the present application.

1 is a perspective view showing a first embodiment of a display device of the present invention, Figure 2 is a cross-sectional view for showing the configuration of the optical sheet in Figure 1, Figures 3a to 3c is an embodiment of the upper optical sheet of the present invention It is sectional drawing which shows various prism shapes.

The display apparatus 100 according to the present invention includes a display panel 110 and a backlight unit for irradiating light to the display panel 110.

The backlight unit is disposed on the rear surface of the display panel 110 to irradiate the back surface of the display panel 110 with light that is the basis of the image display.

Here, the display panel 110 may be formed of a conventional liquid crystal panel. As is well known, the liquid crystal panel includes a TFT substrate having a thin film transistor and a pixel electrode (not shown), a color filter substrate provided to face the TFT substrate, and having a color filter and a common electrode formed thereon, the TFT. It consists of liquid crystal injected between the substrate and the color filter substrate, and displays an image according to a drive signal and a data signal applied from the outside.

The backlight unit of the present embodiment includes a light source 120, an upper optical sheet 130, and a lower optical sheet 140.

That is, the backlight unit of the present invention is configured to freely adjust the waveguide and the uniformity of the emitted light through the microstructured optical sheet without using a light guide plate for guiding light.

In the present embodiment, the backlight unit is an edge-type backlight unit in which the light source 120 is disposed on one side of the upper optical sheet 130. However, the present invention is not limited thereto, and the light source 120 may be disposed on at least one side of the upper optical sheet 130.

A point light source such as a light emitting diode (LED) is used as the light source 120. There is no limitation to the light emitting diode, and a white light emitting diode may be used, or a combination of three light emitting diodes generating light of red (R), green (G), and blue (B) may be used.

Unlike the present embodiment, the light source 120 may be a linear light source such as a cold cathode fluorescent lamp (CCFL) or an external electrode fluorescent lamp (EEFL). In this case, the backlight unit may further include a light source reflector (not shown) surrounding the light source 120 and facing the side surface of the upper optical sheet 130. The light source reflector may be made of metal or plastic, and may coat an inner wall with a material capable of reflecting light. The light source reflector reflects light generated from the light source 120 toward the upper optical sheet 130 to improve light utilization efficiency.

In the embodiment of the present invention, the upper optical sheet 130 guides the light emitted from the light source 120 and exits toward the rear surface of the display panel 110.

The upper optical sheet 130 includes a light incident portion, a light facing portion, a light emitting surface, and a reflecting surface, and the light sources 120 are disposed along the light incident portion and spaced apart from each other at regular intervals.

The light exit surface of the upper optical sheet 130 is disposed toward the rear surface of the display panel 110, and the light emitted from the light source 120 is emitted from the light incident portion of the upper optical sheet 130 to the light emitting portion. A prism perpendicular to the light source 120 is formed to guide.

That is, the light emitted from the light source 120 is introduced into the upper optical sheet 130 through the light incident part.

Thereafter, the light incident on the upper optical sheet 130 is transmitted through a prism formed in the light exiting surface and transmitted in a direction substantially parallel to the viewing plane of the display panel 110. Make luminance uniform.

In the present invention, the prism may be formed in various forms, as shown in the embodiments shown in Figures 3a to 3c.

That is, as shown in the figure, it may be composed of an isosceles prism symmetrical or non-symmetrical about the axis of symmetry.

Since the prism has both a total internal reflection function and a light transmission function, the trapezoid prism may be configured to be symmetric along the axis of symmetry or not to be symmetrical. In addition, mixtures thereof may also be used.

On the other hand, a certain amount of total internal reflection occurs, the other can also be used a quarter prism that allows forced transmission.

Here, the prism may be made of any one selected from a transparent polymer material PMMA, PC, PET, UV curable resin, the processing method is compression molding by compression mold and processing method for molding the prism with UV curable resin on the substrate, injection molding Molding and the like can also be used.

On the other hand, in another configuration of the present invention, the prism may be formed in the shape of an R-prism or a lenticular pattern.

That is, the upper optical sheet of the present invention is configured by using an optical film or an optical sheet having an array of microlenses on the light emitting surface of the display panel 110 side of the backlight unit.

Herein, in order to realize a slimming of the backlight unit, the thickness of the optical film or the optical sheet is suitable to a thickness of 0.1 to 1.5 mm, and the optical sheet has a pitch, curvature, By adjusting the Sag value, the light emission uniformity of the light incident on the optical sheet can be adjusted.

As shown in FIG. 9, the curvature or Sag value of the lens curvature at the light incident part of the upper optical sheet may be adjusted from 100% to 30% at the center position 5. On the other side, the light-emitting part 9 can adjust to 100% level.

Through the variable pattern of the optical sheet array, it is possible to uniformly irradiate incident light to the LCD panel by improving the overall luminance uniformity of the side-illumination LED backlight.

In addition, as shown in FIG. 10, the luminance at the light incidence part 1 at the front end of the LED and at the front end of the LED no. 5 is changed again.

On the other hand, the light introduced into the inside of the upper optical sheet 130 and totally reflected should be scattered and reflected in order to be emitted to the display panel 110. For this purpose, a light scattering pattern may be formed on the reflective surface of the upper optical sheet 130. have.

For example, a light scattering pattern may be formed on the reflective surface opposite to the light emitting surface by dot-printing or the like.

On the other hand, the backlight unit of the present invention should be provided with a control means for maintaining the uniformity of the luminance away from the light source (120).

In the present invention, in order to realize uniform irradiation of the light emitted from the light source 120, the upper optical sheet 130 and the lower optical sheet 140 is provided spaced apart a predetermined interval, the lower optical sheet 140 is reflected Control of the ratio between and refraction (internal total reflection) is necessary.

As a control means for maintaining the uniformity of the above-described brightness, the scattering reflection pattern 142 is formed on one surface of the lower optical sheet 140, and the density increases from the light incident portion to the light portion to maintain the light uniformity.

The scattering reflection pattern 142 is formed on the front surface of the lower optical sheet 140, that is, on the light exit surface, and is formed to increase the density from the light incidence portion to the light portion to maintain the light uniformity.

The scattering reflection pattern 142 may be configured to be opaque or translucent as is well known.

4A to 4B are perspective views illustrating embodiments of the lower optical sheet of the present invention. The scattering reflection pattern 142 may be formed of a dot shape 142 or a stripe shape 242.

The dot-shaped scattered reflection pattern 142 increases in density as it moves away from the light source, and the method of controlling the density of the dot pattern uses a method of increasing or decreasing the interval between dots or increasing the area of the dot.

The dot-shaped scattering reflection pattern 142 may be implemented by molding a method such as screen printing, etching, painting, sanding, and an embossed shape by a method such as injection molding.

In addition, as a method for realizing uniform irradiation, the scattering reflection pattern 242 may be configured in an opaque or translucent stripe shape arranged to be parallel to the light source 120.

The stripe-shaped scattering reflection pattern 242 increases the density of the stripe shape as it moves from the light incident portion to the light portion. The method of increasing the density in this way uses a method of densifying the spacing of stripe shapes of the same area or increasing the area of stripe shapes at the same spacing.

Here, the same method as that of the dot shape may be used to process the scattering reflection pattern 242 having the stripe shape.

The opaque stripe-shaped scattering reflection pattern 242 has ease of processing and the like and is easy to apply to a large display device.

In addition, although not shown, as another embodiment of the scattering reflection pattern for maintaining the uniformity of the light, a form in which the arrangement of the dots and the stripe shape is combined is possible.

Meanwhile, the backlight unit of the present invention may further include a reflective sheet 150. The reflective sheet 150 is disposed on the rear surface of the lower optical sheet 140 and reflects the leaked light to be incident again.

The reflective sheet 150 may be manufactured by coating silver (Ag) on base materials such as SUS, BRASS, Aluminum, PET, or by coating titanium (Ti) to prevent damage due to heat absorption.

Alternatively, the reflective sheet 150 may be formed by dispersing light scattering micro-pores in a resin sheet such as PET.

FIG. 5 is a perspective view showing a second embodiment of the display device of the present invention, FIG. 6 is a cross-sectional view in FIG. 5, and FIG. 7A is a cross-sectional view showing a light incident part of the lower optical sheet in the second embodiment of the present invention. FIG. 7B is a cross-sectional view illustrating the light facing part of the lower optical sheet in the second embodiment of the present invention.

The second embodiment of the present invention includes a light source 120, an upper optical sheet 130, and a lower optical sheet 340.

Here, since the light source 120 and the upper optical sheet 130 are the same as in the above-described first embodiment, a detailed description thereof will be omitted.

As a means for uniformly irradiating the light emitted from the light source 120 to the display panel 110, the angle of the reflecting surface of the lower optical sheet 140 is adjusted as the moving from the light incident portion to the light portion of the micro structure ( Micro Structured)

The lower optical sheet 340 will be described in addition.

The lower optical sheet 340 has a prismatic structure for adjusting uniformity on the display panel 110, and in the light incident part B, as shown in FIG. 7A, a prism shape having a small inclination angle near the smooth surface is shown. As shown in FIG. 7B, the prism angle increases as the light is moved toward the light portion A. FIG.

Here, Fresnel shape design data for the prism shape is as follows.

Where c is curvature, k is conic const, and AD to AG are Apherical constants. (Unit is mm)

Each pitch of the prism can be configured to a pitch of several microns to hundreds of microns.

Optical properties of the surface of the prismatic structure is preferably composed of scattering reflection or mirror reflection surface.

The edge-type backlight unit of the present invention configured as described above may adjust the uniformity of light through the lower optical sheets 140 and 340 while guiding the light emitted from the light source 120 through the upper optical sheet 130. In addition, while constituting an edge type backlight unit that does not apply a light guide plate, which is impossible in the existing technology, the manufacturing cost is significantly reduced, and the weight and the depth of the set are slim.

In the embodiment of the present invention, the effect of the arrangement of the light source has been described only by the configuration on one side, but various implementations such as the two side and the four side are possible, and therefore, as those skilled in the art having a general knowledge of the specific implementation method. Application would be possible.

In the detailed description of the present invention described above with reference to the preferred embodiments of the present invention, those skilled in the art or those skilled in the art having ordinary skill in the art will be described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

100: display device 110: display panel
120: light source 130: upper optical sheet
140: lower optical sheet 142: scattering reflection pattern
150: reflective sheet

Claims (21)

A light source installed on one side of the display panel and configured to generate a plurality of LEDs;
An upper optical sheet for providing the light to the display panel by forming a prism perpendicular to the light source on one surface to guide the light emitted from the light source from the light receiving part to the light receiving part;
A lower optical sheet installed at a predetermined distance from the upper optical sheet and having a scattering reflection pattern formed on a front surface thereof; And
A reflection sheet installed on a rear surface of the lower optical sheet and reflecting light leaked from the lower optical sheet toward the light exit surface;
Including;
The prism is formed on the light exit surface of the upper optical sheet,
The scattering reflection pattern is formed of a combination of dot and stripe shape, the density of the light guide plate edge type backlight unit, characterized in that the density increases from the light incident to the light portion to maintain the uniformity. delete The method according to claim 1,
The prism is a light guide plate edge type backlight unit, characterized in that consisting of an symmetrical or non-symmetrical prism around the axis of symmetry. delete The method according to claim 1,
And the prism is made of any one selected from a transparent polymer material, PMMA, PC, PET, and UV curable resin. delete delete The method according to claim 1,
The scattering reflecting pattern is an opaque or translucent non-light guide plate edge type backlight unit, characterized in that configured. delete The method according to claim 1,
Stripe shape of the scattering reflection pattern is arranged to be parallel to the light source, densely spaced stripe shape of the same area, or increase the density by increasing the area of the stripe shape at the same interval, characterized in that the edge of the light-free plate Backlight unit. The method according to claim 1,
The dot shape of the scattering reflection pattern is a light guide plate edge type backlight unit, characterized in that to increase the density by increasing or decreasing the interval between the dots or the area of the dot. delete delete delete A light source installed on one side of the display panel and configured to generate a plurality of LEDs;
An upper optical sheet for providing the light to the display panel by forming a prism perpendicular to the light source on one surface to guide the light emitted from the light source from the light receiving part to the light receiving part;
A lower optical sheet installed at a predetermined distance from the upper optical sheet and having a prismatic structure for uniformly irradiating light emitted from the light source to the display panel on a reflective surface; And
A reflection sheet installed on a rear surface of the lower optical sheet and reflecting light leaked from the lower optical sheet toward the light exit surface;
Including;
The reflecting surface of the lower optical sheet has a shape of a micro structure in which the angle is adjusted as the light moves from the light incident portion to the light facing portion, while the light receiving portion has a prism shape having a small inclination angle close to the smooth surface. Consisting of increasing structure,
The light guide plate edge type backlight unit, characterized in that the scattering reflection pattern is formed on the light exit surface of the lower optical sheet. delete delete delete delete delete Display panel;
Edge type backlight unit according to any one of claims 1, 3, 5, 8, 10, 11, 15 for irradiating light to the display panel;
Display device comprising a.

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