KR102649049B1 - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device, and in particular, to a liquid crystal display device that realizes high brightness and is lightweight and thin.
A feature of the present invention is that the backlight unit includes a light collection sheet including a second diffusion layer, a first light collection layer and a bottom light emission pattern on the upper and lower surfaces of the light guide plate, and the reflector further includes a first diffusion layer and a low refractive index layer. It is done.
Through this, the light incident inside the light guide plate is uniformly processed into a high-quality surface light source and provided to the liquid crystal panel without the need for a plurality of optical sheets on top of the light guide plate. Therefore, light loss due to multiple optical sheets can be prevented, and a high-brightness surface light source can be provided as a liquid crystal panel.
In addition, a lightweight and thin liquid crystal display device can be provided, and the work process time can be reduced, thereby improving process efficiency.

Description

Liquid crystal display device

The present invention relates to a liquid crystal display device, and in particular, to a liquid crystal display device that realizes high brightness and is lightweight and thin.

Recently, the display field has also developed rapidly in line with the information age, and in response to this, a liquid crystal display device (LCD) has been developed as a flat panel display device (FPD) with the advantages of thinner, lighter, and lower power consumption. LCD), plasma display panel device (PDP), electroluminescence display device (ELD), and field emission display device (FED) were introduced, replacing the existing cathode ray tube. : CRT) is rapidly replacing it and is in the spotlight.

Among these, liquid crystal displays are excellent at displaying moving images and are most actively used in fields such as laptops, monitors, and TVs due to their high contrast ratio. Liquid crystal displays are devices that do not have their own light-emitting elements and require a separate light source. is requested.

Accordingly, a backlight unit equipped with a light source is provided on the back of the liquid crystal panel to irradiate light toward the front of the liquid crystal panel, and only through this, an image with identifiable brightness is realized.

Meanwhile, general backlight units are divided into side light type and direct type according to the arrangement structure of the light source. The side light type has a structure in which one or a pair of light sources are placed on one side of the light guide plate. It has a structure in which two or two pairs of light sources are arranged on each side of the light guide plate, and the direct type has a structure in which several light sources are arranged in the lower part of the optical sheet.

Here, the sidelight type is easier to manufacture than the direct type, and has the advantage of being thinner, lighter in weight and lower in power consumption compared to the direct type.

Figure 1 is a cross-sectional view of a liquid crystal display device using a general sidelight type backlight unit.

As shown, a typical liquid crystal display device consists of a liquid crystal panel 10, a backlight unit 20, a guide panel 30, a cover button 50, and a case top 40.

The liquid crystal panel 10 is a part that plays a key role in image expression and is composed of first and second substrates 12 and 14 bonded face to face with a liquid crystal layer in between. Printed circuit boards (not shown) are connected to each other along two adjacent edges of the liquid crystal panel 10 via connecting members (not shown).

At this time, polarizers 19a and 19b that selectively transmit only specific light are attached to each outer surface of the first and second substrates 12 and 14 of the liquid crystal panel 10.

In addition, behind the liquid crystal panel 10, there is an LED assembly 29 arranged along the longitudinal direction of at least one edge of the guide panel 30, a white or silver reflector 25 mounted on the cover button 50, and , a backlight unit 20 including a light guide plate 23 mounted on the reflector 25 and an optical sheet 21 disposed on top of the light guide plate 23 is provided.

Here, the LED assembly 29 consists of a plurality of LEDs 29a and a PCB 29b on which the plurality of LEDs 29a are mounted.

The liquid crystal panel 10 and the backlight unit 20 have edges surrounded by a rectangular guide panel 30, a case top 40 surrounding the upper edge of the liquid crystal panel 10, and a backlight unit 20. The cover buttons 50 that cover are combined at the front and rear, respectively, and are integrated through the guide panel 30.

Therefore, the light emitted from the LED assembly 29 is incident on the light guide plate 23 and then exits as a surface light source in the direction of the liquid crystal panel 10. While passing through the optical sheet 21, it is processed to high quality with uniform luminance to produce the liquid crystal panel. It is incident on 10, and thus the liquid crystal panel 10 displays an image to the outside.

Meanwhile, as the LED assembly 29 including a plurality of LEDs 29a that substantially supply light is located only on one side of the light guide plate 23, the LED assembly 29 is located further forward from the light guide plate 23. A greater amount of light is emitted in the opposite direction.

Therefore, in order to allow a large amount of light to exit in front of the light guide plate 23 and enter the liquid crystal panel 10, at least three light collection sheets and a diffusion sheet are installed on the upper part of the light guide plate 23. It is essential to have a configuration in which several optical sheets 21 are interposed.

However, when multiple optical sheets 21 are placed above the light guide plate 23 in this way, a large amount of light can be emitted in front of the light guide plate 23, but the light located in front of the light guide plate 23 This causes a problem in that the optical efficiency is lowered by the optical sheet 21.

That is, if the amount of light emitted from the LED 29a of the LED assembly 29 is 100%, the amount of light passing through the light guide plate 23 and the multiple optical sheets 21 of the light collection sheet and diffusion sheet is 50%. It doesn't even reach.

This is because in the process of light passing through the light guide plate 23 passing through the multiple optical sheets 21, a large amount of light is absorbed or extinguished and lost by the multiple optical sheets 21.

In addition, the use of multiple optical sheets 21 hinders the thinness and lightness of the liquid crystal display device, which has been recently required, and increases the work process time in the modularization process of the liquid crystal display device, which reduces process efficiency. It also causes

The present invention is intended to solve the above-mentioned problems. The first purpose is to provide a liquid crystal display device with improved light efficiency, and the second purpose is to provide a high brightness liquid crystal display device through this.

In addition, the third purpose is to achieve a lightweight and thin liquid crystal display device while at the same time reducing assembly time and material costs during the modularization process of the liquid crystal display device.

In order to achieve the object as described above, the present invention includes a liquid crystal panel, a first light collecting layer located on the lower part of the liquid crystal panel, and an upper surface corresponding to the back of the liquid crystal panel, and a lower surface emitting light. A light guide plate provided with a pattern, a reflector located below the light guide plate and sequentially provided with a first diffusion layer, a low refractive layer, and a reflective layer from the lower surface of the light guide plate, and a second reflector plate located above the light guide plate and having a first upper surface. It includes a light collection sheet provided with two light collection layers and a second diffusion layer on the lower surface, and an LED assembly arranged along the light incident surface of the light guide plate, wherein the bottom light emission pattern is a portion of the light incident on the inside of the light guide plate. A liquid crystal display device is provided to emit light toward the reflector.

As described in detail above, according to the present invention, the backlight unit includes a light collection sheet including a second diffusion layer, a first light collection layer and a bottom light emitting pattern on the upper and lower surfaces of the light guide plate, and a first diffusion layer and a lower light emitting pattern on the reflector. By further providing a refractive layer, it has the effect of uniformly processing the light incident into the light guide plate into a high-quality surface light source and providing it to the liquid crystal panel without interposing a plurality of optical sheets on top of the light guide plate.

Through this, light loss caused by multiple optical sheets can be prevented, which has the effect of providing a high-brightness surface light source as a liquid crystal panel.

In addition, it has the effect of providing a lightweight and thin liquid crystal display device, and has the effect of improving process efficiency by reducing the work process time.

Figure 1 is a cross-sectional view of a liquid crystal display device using a general sidelight type backlight unit.
Figure 2 is a perspective view schematically showing a liquid crystal display device according to an embodiment of the present invention.
Figure 3 is an exploded perspective view of the backlight unit of Figure 2.
Figures 4a to 4c are perspective views schematically showing the bottom light emission pattern.
Figure 5 is a cross-sectional view schematically showing the cross-section of Figure 3.
6A to 6B are simulation results of comparing and measuring the luminance of backlight units according to an embodiment of the present invention.

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

Figure 2 is a perspective view schematically showing a liquid crystal display device according to an embodiment of the present invention.

As shown, the liquid crystal display device according to an embodiment of the present invention is largely composed of a liquid crystal panel 110, a backlight unit 120, a guide panel 130, a case top 140, and a cover button 150. .

At this time, if the direction in the drawing is defined for convenience of explanation, the backlight unit 120 is disposed at the rear of the liquid crystal panel 110 under the premise that the display surface of the liquid crystal panel 110 faces forward, and the backlight unit 120 is disposed at the rear of the liquid crystal panel 110 and covers the outside of the liquid crystal panel 110. The case top 140 is located in front of the liquid crystal panel 110 with the rectangular-shaped guide panel 130 wrapped around it, and the cover button 150 is located on the back of the backlight unit 120, so that it can be viewed from the front and back. combined and unified.

Let's look at each of these in more detail.

First, the liquid crystal panel 110 is a part that plays a key role in image expression of the liquid crystal display device, and consists of a first substrate 112 and a second substrate 114 bonded facing each other, and a liquid crystal layer interposed between them. Includes (not shown).

Although not shown in the drawing, on the inner surface of the first substrate 112, called the lower substrate or array substrate, a plurality of gate lines and data lines intersect to define a pixel, and a thin film transistor is installed at each intersection. : TFT) is provided and connected in one-to-one correspondence with the transparent pixel electrode formed in each pixel.

And on the inner surface of the second substrate 114, called the upper substrate or color filter substrate, color filters of red (R), green (G), and blue (B) colors, for example, corresponding to each pixel, and these A black matrix is provided that surrounds each and covers the gate line, data line, and thin film transistor.

In addition, a transparent common electrode is provided that covers red (R), green (G), and blue (B) color filters and a black matrix.

And upper and lower alignment films (not shown) that determine the initial molecular arrangement direction of the liquid crystal are interposed at the boundary between the first and second substrates 112 and 114 and the liquid crystal layer (not shown), and the first and second substrates To prevent leakage of the liquid crystal layer (not shown) filled between (112, 114), a seal pattern (not shown) is formed along the edges of both substrates (112, 114).

Additionally, polarizing plates 119a and 119b (see FIG. 5) that selectively transmit only specific light are attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

Along one edge of the liquid crystal panel 110, a printed circuit board 117 is connected via a connecting member 116 such as a flexible circuit board or a tape carrier package (TCP) to form a cover during the modularization process. Vertum (150) is flipped to the back and adheres closely.

Therefore, when the thin film transistor selected for each gate line is turned on by the on/off signal of the thin film transistor scanned and transmitted to the gate line, the liquid crystal panel 110 transmits the image signal of the data line to the corresponding pixel electrode. is transmitted, and the resulting electric field between the pixel electrode and the common electrode changes the arrangement direction of the liquid crystal molecules, resulting in a difference in transmittance.

In addition, the liquid crystal display device according to the present invention is provided with a backlight unit 120 that supplies light from the back of the liquid crystal panel 110 so that the difference in transmittance shown by the liquid crystal panel 110 is expressed externally.

A high-brightness surface light source implemented from the backlight unit 120 is provided to the liquid crystal panel 110, and the liquid crystal panel 110 displays an image.

The backlight unit 120 includes an LED assembly 129 arranged along at least one edge in the longitudinal direction of the cover button 150, a reflector 400, a light guide plate 300 mounted on the reflector 400, and It includes an optical sheet 200 located above the light guide plate 300.

The LED assembly 129 is a light source of the backlight unit 120 and includes a plurality of LEDs 129a and a PCB 129b on which the plurality of LEDs 129a are mounted at regular intervals.

The light guide plate 300, on which the light emitted from the plurality of LEDs 129a is incident, includes a first light collecting layer 313 on the upper surface (311a, see FIG. 3) and a lower surface (311b, see FIG. 3). By including the light emission pattern 315, the light incident from the LED 129a is allowed to travel inside the light guide plate 300 through several total reflections, so that the light spreads evenly inside the light guide plate 300, and at the same time, some of the light is transmitted to the light guide plate ( It is emitted toward the reflector 400 located at the bottom of 300).

In addition, the reflector 400 is further provided with a first diffusion layer 413 (see FIG. 3) and a low refractive index layer 415 (see FIG. 3), so that the light passing through the lower surface 311b (see FIG. 3) of the light guide plate 300 By reflecting light toward the liquid crystal panel 110, a high-brightness surface light source is provided to the liquid crystal panel 110.

At this time, the optical sheet on top of the light guide plate 300 is made up of only one light collection sheet 200 including the second diffusion layer 205 (see FIG. 3), and together with the first light collection layer 313 of the light guide plate 300, the light guide plate 300 The light passing through 300 is condensed to provide a higher brightness surface light source to the liquid crystal panel 110.

That is, in the liquid crystal display device according to an embodiment of the present invention, the backlight unit 120 consists of only an LED assembly 129, a light guide plate 300, a reflector 400, and one light collection sheet 200.

Through this, the backlight unit 120 according to an embodiment of the present invention provides a high-brightness surface light source to the liquid crystal panel 110, but prevents light efficiency from being reduced as multiple optical sheets (21 in FIG. 1) are provided. It can be prevented.

In addition, the liquid crystal display device can be made lightweight and thin, and at the same time, assembly time and material costs can be reduced during the modularization process of the liquid crystal display device.

We will look at this in more detail later.

This liquid crystal panel 110 and backlight unit 120 are modularized through a case top 140, a guide panel 130, and a cover button 150.

Here, the case top 140 has a square frame shape with a cross-section bent in an “L” shape to cover the top and side edges of the liquid crystal panel 110, and the front of the case top 140 is opened to expose the liquid crystal panel 110. It is configured to display images implemented in .

In addition, the cover button 150, on which the liquid crystal panel 110 and the backlight unit 120 are seated and which serves as the basis for assembling the entire liquid crystal display device, is formed in the shape of a single square plate, the edges of which are vertically bent to a predetermined height. .

The guide panel 130, which has a square frame shape and is seated on the cover button 150 and surrounds the edges of the liquid crystal panel 110 and the backlight unit 120, is combined with the case top 140 and the cover button 150.

At this time, the case top 140 is sometimes referred to as a top cover or top case, the guide panel 130 is also referred to as a support main, main support, or mold frame, and the cover button 150 is referred to as a bottom cover or lower cover. Sometimes you lose.

Meanwhile, recently, in order to implement a lightweight and thin liquid crystal display device, the case top 140 and cover button 150 were removed, and the liquid crystal panel 110 and backlight were connected through adhesive tape (not shown) and a guide panel 130. The unit 120 may also be modularized. Through this, it is possible to achieve a lightweight and thin design while also reducing material costs.

In the liquid crystal display device of the present invention described above, the backlight unit 120 includes one light collection sheet 200 including a second diffusion layer 205 (see FIG. 3) and the upper and lower surfaces 311a and 311b of the light guide plate 300. (see FIG. 3) is provided with a first light collection layer 313 and a bottom light emitting pattern 315, and the reflector 400 is provided with a first diffusion layer (413, see FIG. 3) and a low refractive index layer (415, see FIG. 3). By further providing the liquid crystal panel 110, a high-brightness, uniform surface light source is provided.

In other words, the liquid crystal display device of the present invention processes the light incident into the light guide plate 300 uniformly into a high-quality surface light source without interposing a plurality of optical sheets (21 in FIG. 1) on the light guide plate 300 to produce liquid crystals. It is provided as a panel 110.

Through this, light loss due to multiple optical sheets (21 in FIG. 1) can be prevented, and a high-brightness surface light source can be provided as a liquid crystal panel.

In addition, the backlight unit 120 has many components, which hinders the light weight and thinness of the liquid crystal display device, or increases the work process time in the modularization process of the liquid crystal display device, reducing process efficiency. A liquid crystal display device can be provided, and work process time can be reduced, thereby improving process efficiency.

That is, the present invention can provide a backlight unit 120 that is efficient and has excellent performance.

Figure 3 is an exploded perspective view of the backlight unit of Figure 2, and Figures 4a to 4c are perspective views schematically showing the bottom light emission pattern.

And, Figure 5 is a cross-sectional view schematically showing the cross-section of Figure 3, and is a cross-sectional view schematically showing the progress of light in the liquid crystal display device.

As shown, the backlight unit 120 includes a white or silver reflector 400 mounted on the cover button (150 in FIG. 2), an LED assembly 129 as a light source arranged along the longitudinal direction of one edge of the light source, and It consists of a light guide plate 300 mounted on the reflector 400 and a light collecting sheet 200 located on top of the light guide plate 300.

The LED assembly 129 is located on one side of the light guide plate 300 to face the light incident surface 311c of the light guide plate 300, and this LED assembly 129 includes a plurality of LEDs 129a and a plurality of LEDs 129a. Includes a PCB (129b) that is mounted at regular intervals.

At this time, the plurality of LEDs 129a emit light having the colors of red (R), green (G), and blue (B), respectively, toward the front toward the light receiving surface 311c of the light guide plate 300, and these plurality of RGB By turning on the LEDs 129a all at once, white light can be created by mixing colors.

In particular, recently, in order to improve luminous efficiency and brightness, blue LED (129a) containing a blue LED chip with excellent luminous efficiency and brightness has been used, and 'cerium-doped yttrium aluminum garnet (YAG: Ce)' as a phosphor. That is, a blue LED 129a made of yellow phosphor is used.

The blue light emitted from the LED 129a passes through the phosphor and mixes with the yellow light emitted by the phosphor, thereby producing white light.

In addition to the LED assembly 129, a fluorescent lamp such as a cold cathode fluorescent lamp or an external electrode fluorescent lamp may be used.

The light guide plate 300, on which light emitted from a plurality of LEDs 129a is incident, is evenly spread over a wide area of the light guide plate 300 as the light incident from the LEDs 129a travels within the light guide plate 300 by total reflection several times. A surface light source is provided to the liquid crystal panel (110 in FIG. 2).

Accordingly, the light guide plate 300 is made of a plastic material such as polymethylmethacrylate (PMMA), an acrylic transparent resin, which is one of the transparent materials capable of transmitting light, or polycarbonate (PC) series. It is manufactured in a flat type.

This light guide plate 300 has excellent transparency, weather resistance, and coloring properties, and thus induces diffusion of light when it passes through.

This light guide plate 300 connects the light entrance surface 311c corresponding to the LED assembly 129 and the opposite light entrance surface 311d, and the light entrance surface 311c and the light entrance surface 311d, and connects the light entrance surface 311c to the upper part where the light is emitted. It consists of a surface 311a, a lower surface 311b facing the reflector 400, and two sides 311e and 311f facing each other.

In addition, the upper surface 311a of the light guide plate 300 is provided with a first light collection layer 313 for concentrating light, and the first light collection layer 313 is positioned along the light guide plate 300 in the first direction (X) defined in the drawing. ), a plurality of strip-shaped prism mountains 313a with repeated peaks and valleys in the cross section are protruding and arranged by being arranged adjacent to each other along the direction crossing the direction perpendicular to the longitudinal direction.

Through this, the light guide plate 300 according to an embodiment of the present invention condenses the light emitted from the upper surface 311a of the light guide plate 300.

In addition, the lower surface 311b of the light guide plate 300 is provided with a bottom light emitting pattern 315. The bottom light emitting pattern 315 allows light incident into the light guide plate 300 to be reflected inside the light guide plate 300 through several total reflections. proceeds so that the light spreads evenly inside the light guide plate 300 and at the same time, some of the light is emitted toward the reflector 400 located at the lower part of the light guide plate 300.

As shown in FIG. 4A, the bottom light emitting pattern 315 is formed in a hemi sphere shape and protrudes from the lower surface 311b. The hemispherical bottom light emitting pattern 315 is formed on the lower surface 311b of the light guide plate 300. ) are distributed and arranged in a relief shape at regular intervals.

At this time, the hemispherical bottom light emitting pattern 315 is formed to have a diameter (w) of 10 to 500㎛, and the height (h) of the bottom light emitting pattern 315 is diameter (w):height (h) = 1: (0.5) ±10%) is preferably formed to satisfy.

That is, the bottom light emitting pattern 315 may be formed to have a diameter (w) of 100 μm, and in this case, the height (h) of the bottom light emitting pattern 315 is formed to have a 50 μm.

In addition, as shown in FIG. 4b, the lower surface light emitting pattern 315 has an inverted trapezoidal cross-section, and a column shape obtained by rotating the inverted trapezoidal shape by 360° may protrude from the lower surface 311b.

At this time, the bottom light emitting pattern 315, which has an inverted trapezoidal cross-section, is formed to have a diameter (w) of 10 to 500㎛, and the height (h) is diameter (w):height (h) = 1: (0.7±10%) ) is preferably formed to satisfy.

In addition, as shown in FIG. 4C, it may be formed to protrude from the lower surface 311b in the shape of a half prism, and the lower surface emitting light pattern 315 of the half prism shape has a diameter (w) of 10 to 500 ㎛. It is formed to have, and the height (h) is preferably formed to satisfy the following: diameter (w):height (h) = 1: (0.58±10%).

At this time, the half-prism-shaped bottom light emitting pattern 315 is formed so that the first inclined surface 315a on the long side faces one direction toward the LED assembly 129, and the second inclined surface 315b on the short side faces the other direction on the opposite side. It is preferable that it is formed to face the direction.

Here, the angle (a1) formed between the first inclined surface 315a of the long side of the half-prism-shaped bottom light emitting pattern 315 and the lower surface 311b of the light guide plate 300 is 30 (±10) degrees, and the angle of the short side is 30 (±10) degrees. The angle a2 formed between the second inclined surface 315b and the lower surface 311b of the light guide plate 300 is preferably formed to be 75 (±10) degrees.

Accordingly, the light incident inside the light guide plate 300 travels inside the light guide plate 300 through total reflection several times through the bottom light emitting pattern 315 provided on the lower surface 311b of the light guide plate 300 and enters the inside of the light guide plate 300. At the same time, some light is emitted through the lower surface 315b of the light guide plate 300.

At this time, the light emitted from the lower part of the light guide plate 300 is reflected by the reflector 400 located below the light guide plate 300 and is emitted again in front of the light guide plate 300, thereby improving the brightness of the light.

For this purpose, the reflector 400 is further provided with a first diffusion layer 413 and a low refractive index layer 415.

Here, looking at the structure of the reflector 400 in more detail, the reflector 400 includes a reflection layer 411 that reflects light emitted from the lower surface 311b of the light guide plate 300, and a first diffusion layer ( 413) and a low refractive index layer 415 interposed between the reflection layer 411 and the first diffusion layer 413 to further diffuse the light.

The reflective layer 411 is made of white opaque synthetic resin, that is, polyethylene terephthalate (PET), polyethylene naphthalate, polymethly methacrylate (PMMA), polycarbonate, and polystyrene. , synthetic resins such as polyolefine, cellulose acetate, and polyvinyl chloride, as well as titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), zinc oxide (ZnO), and lead carbonate (PbCO ₃ ). It is composed of white pigments such as barium sulfate (BaSO ₄ ), calcium carbonate (CaCO ₃ ), and aluminum oxide (Al ₂ O ₃ ).

Since the reflective layer 411 has light reflection properties, the light passing through the lower surface 311b of the light guide plate 300 is substantially reflected by the reflective layer 411 and is emitted toward the front of the light guide plate 300.

The first diffusion layer 413 located above the reflection layer 411 includes a light diffusion component such as a bead or fiber, and the light diffusion component prevents light from being partially concentrated by dispersing the light. do.

Through this, the first diffusion layer 413 diffuses the light by refracting and scattering the incident light, and spreads the light reflected by the reflection layer 411 while emitting uniform light to the front of the light guide plate 300. Do it.

At this time, light diffusion components such as beads or fibers are comprised of a binder resin. Here, the binder resin has high transparency, excellent light transmittance, and easy viscosity control. For example, polyethylene terephthalate (PET). ), polyethylene naphthalate, acrylic resin (polymethly methacrylate (PMMA)), polycarbonate, polystyrene, polyolefine, cellulose acetate, polyvinyl chloride, etc. It can be done.

In addition, although not shown in the drawing, the first diffusion layer 413 may include fine patterns in addition to light diffusion components such as beads or fibers to adjust the scattering angle of light, thereby diffusing light and processing it into uniform light.

Micropatterns can be configured in various ways, such as elliptical patterns and polygon patterns, and use a hologram pattern to refract the light incident by the interference pattern in an asymmetrical direction. The concentrated light can be spread at a more inclined angle.

As a result, light is dispersed through the first diffusion layer 413 to prevent light from being partially concentrated.

The refractive index of the low refractive layer 415 is 1.0 to 1.4, and has a lower refractive index than the first diffusion layer 413, which has a refractive index of 1.5 or more. The light incident on the first diffusion layer 413 is divided into the first diffusion layer 413 and Refraction of light occurs at the boundary of the low-refraction layer 415 according to Snell's law, and this refraction causes the refracted light to be reflected or scattered because the refraction angle is formed larger than the incident angle, so the low-refraction layer ( 415) further diffuses the light incident on the first diffusion layer 413.

Since the light diffused in the low refractive index layer 415 is diffusely reflected in the process of being reflected by the reflection layer 411, the total reflectance of the reflector 400 is also improved.

That is, the light that repeats the path of the first diffusion layer 413 - the low refractive index layer 415 - the reflection layer 411 is refracted at the boundary of each medium and is diffused or reflected, and the diffused light is diffusely reflected, so the reflector The total reflectance of (400) is improved.

In addition, the light collection sheet 200 located on the upper part of the light guide plate 300 is arranged adjacent to the support layer 201 in a strip shape on the upper part of the support layer 201, so that a plurality of prism mountains 203a in the form of repeating peaks and valleys are used to dissipate heat. It includes a second light collecting layer 203 protruding from the support layer 201, and a second diffusion layer 205 is provided below the support layer 201.

At this time, the prism mountains 203a located in the second light collecting layer 203 are protruding and arranged in a direction transverse to the longitudinal direction of the light collecting sheet 200 along the second direction (Y) defined in the drawing, so that the light guide plate 300 ) are arranged to be perpendicular to each other and the prism mountains 313a located in the first light collecting layer 313.

In addition, the second diffusion layer 205 located below the support layer 201 is composed of a light diffusion component such as beads, or is formed without beads and forms a fine pattern on the second diffusion layer 205. You can also configure it.

The second diffusion layer 205 disperses light to prevent spots due to partial concentration of light, and serves to control the direction of light so that it travels to the second light collection layer 203.

This light collection sheet 200 diffuses and condenses the light passing through the light guide plate 300 and causes a uniformly processed high-brightness surface light source to enter the liquid crystal panel (110 in FIG. 2).

Here, looking in more detail at the process of light in the liquid crystal display device according to an embodiment of the present invention, the light emitted from the plurality of LEDs 129a of the LED assembly 129 passes through the light incident surface 311c of the light guide plate 300. The light incident on the inside of the light guide plate 300 undergoes total reflection several times within the light guide plate 300 and spreads evenly over a wide area of the light guide plate 300 as it travels within the light guide plate 300.

At this time, some of the light that is totally reflected within the light guide plate 300 several times and travels within the light guide plate 300 is emitted toward the front of the light guide plate 300 through the upper surface 311a of the light guide plate 300. The light guide plate ( The light emitted toward the front of the light guide plate 300 is primarily concentrated by the prism mountains 313a of the first light collection layer 313 located on the upper surface 311a of the light guide plate 300 and is located at the top of the light guide plate 300. It passes through the light collecting sheet 200.

The light passing through the light collection sheet 200 is partially diffused through the second diffusion layer 205 located at the bottom of the light collection sheet 200, and then is secondaryly diffused through the prism acid 203a of the second light collection layer 203. The light is concentrated, processed into a high-quality, uniform surface light source, and provided as a liquid crystal panel (110 in FIG. 2).

In addition, some of the light that is totally reflected several times within the light guide plate 300 and travels within the light guide plate 300 is refracted by the concave-shaped bottom light emitting pattern 315 formed on the lower surface 311b of the light guide plate 300. It is emitted through the lower surface 311b of the light guide plate 300 toward the reflector 400 located below the light guide plate 300.

And, the light emitted from the lower part of the light guide plate 300 is diffused by the first diffusion layer 413 of the reflector 400 located below the light guide plate 300 and enters the low refractive index layer 415 of the reflector 400. As a result, the light incident on the low refractive index layer 415 is further diffused in the process of being reflected by the reflective layer 411 located below the low refractive index layer 415 and is reflected toward the light guide plate 300.

Therefore, the light reflected toward the light guide plate 300 is transmitted by the prism mountain 313a of the first light collection layer 313 located on the upper surface 311a of the light guide plate 300 in the process of passing through the light guide plate 300. The first light is collected and passes through the light collection sheet 200 located above the light guide plate 300.

And the light passing through the light collection sheet 200 is partially diffused through the second diffusion layer 205 located at the bottom of the light collection sheet 200, and then collected through the prism acid 203a of the second light collection layer 203. It is processed into a high-brightness, uniform surface light source and provided as a liquid crystal panel (110 in FIG. 2).

That is, the light emitted from the upper surface 311a and the lower surface 311b of the light guide plate 300 is processed into a high-brightness, uniform surface light source and provided to the liquid crystal panel (110 in FIG. 2).

In particular, the liquid crystal display device of the present invention allows light incident into the light guide plate 300 to be emitted toward the front of the light guide plate 300 without interposing a plurality of optical sheets (21 in FIG. 1) on top of the light guide plate 300. Therefore, it is processed into a high-quality, uniform surface light source and provided as a liquid crystal panel (110 in FIG. 2).

Through this, since there is no need to place multiple optical sheets (21 in FIG. 1) on the light guide plate 300, light loss due to multiple optical sheets (21 in FIG. 1) can be prevented. Therefore, a high brightness amount of light can be provided to the liquid crystal panel (110 in FIG. 2).

In addition, the backlight unit 120 has many components, which hinders the light weight and thinness of the liquid crystal display device, or increases the work process time in the modularization process of the liquid crystal display device, reducing process efficiency. A liquid crystal display device can be provided, and work process time can be reduced, thereby improving process efficiency.

6A to 6B are simulation results of comparing and measuring the luminance of backlight units according to an embodiment of the present invention.

Prior to explanation, Figure 6a shows the LED assembly (29 in Figure 1), the reflector (25 in Figure 1), the light guide plate (23 in Figure 1), and one diffusion sheet and two light collection sheets on top of the light guide plate (23 in Figure 1). It has the structure of a general backlight unit (20 in FIG. 1) in which an optical sheet (21 in FIG. 1) is located.

Here, by comparing FIGS. 6A and 6B, it can be seen that the luminance profile of the light passing through the backlight unit is similar.

That is, the backlight unit (120 in FIG. 3) according to an embodiment of the present invention includes an LED assembly (129 in FIG. 5), a reflector (400 in FIG. 5), a light guide plate (300 in FIG. 5), and one light collection sheet (FIG. Even though it only consists of 200 in 5), it is possible to implement the same brightness profile as a general backlight unit (20 in FIG. 1) in which three optical sheets (21 in FIG. 1) are located.

In particular, it can be confirmed that the front luminance of the backlight unit (120 in FIG. 3) according to the embodiment of the present invention in FIG. 6B is measured to be higher, which means that the backlight unit (120 in FIG. 3) according to the embodiment of the present invention ) means that high-brightness, high-quality processed light can be supplied to the liquid crystal panel (110 in FIG. 3).

That is, the liquid crystal display device according to an embodiment of the present invention is composed of one light collection sheet (200 in FIG. 5) including a second diffusion layer (205 in FIG. 5) and the upper and lower surfaces (300 in FIG. 5) of the light guide plate (300 in FIG. 5). 5 (311a, 311b) is provided with a first light collection layer (313 in FIG. 5) and a bottom light emitting pattern (315 in FIG. 5), and the reflector (400 in FIG. 5) is provided with a first diffusion layer (413 in FIG. 5) and a low light emitting layer (313 in FIG. 5). By further providing a refractive layer (415 in FIG. 5), a high-brightness, uniform surface light source is provided to the liquid crystal panel (110 in FIG. 2).

Through this, light loss due to multiple optical sheets (21 in FIG. 1) can be prevented, and a high-brightness surface light source can be provided as a liquid crystal panel (110 in FIG. 2).

In addition, compared to the existing case where the number of components of the backlight unit (120 in FIG. 3) impedes the lightweight and thinness of the liquid crystal display device, or the work process time increases in the modularization process of the liquid crystal display device, reducing the efficiency of the process. It is possible to provide a lightweight and thin liquid crystal display device, and the work process time can be reduced, thereby improving process efficiency.

In other words, the present invention can provide a backlight unit (120 in FIG. 3) that is efficient and has excellent performance.

The present invention is not limited to the above embodiments, and can be implemented with various changes without departing from the spirit of the present invention.

120: backlight unit
129: LED assembly (129a: LED, 129b: PCB)
200: light collection sheet (201: support layer, 203: second light collection layer, 205: second diffusion layer)
300: light guide plate (311a, 311b: upper and lower surfaces, 311c: light receiving surface, 313: first light collecting layer, 315: lower light emitting pattern)
400: Reflector (411: Reflection layer, 413: First diffusion layer, 415: Low refractive index layer)

Claims (11)

a liquid crystal panel;
a light guide plate located below the liquid crystal panel, having a first light collecting layer on an upper surface corresponding to the back of the liquid crystal panel, and a bottom light emitting pattern on the lower surface;
a reflector located below the light guide plate and including a first diffusion layer, a low refractive index layer having a lower refractive index than the first diffusion layer, and a reflection layer sequentially from the lower surface of the light guide plate;
a light collection sheet located on an upper part of the light guide plate and including a support layer, a second light collection layer disposed on an upper surface of the support layer, and a second diffusion layer disposed on a lower surface of the support layer;
It includes an LED assembly arranged along the light receiving surface of the light guide plate,
The bottom light emitting pattern causes some of the light incident into the light guide plate to be emitted toward the reflector,
The first diffusion layer is disposed in an area overlapping the entire lower surface of the light guide plate, and the low refractive index layer is disposed on the entire upper surface of the first diffusion layer,
A liquid crystal display device wherein the low refractive index layer has a refractive index of 1.0 to 1.4 and the first diffusion layer has a refractive index of 1.5 or more.
delete According to claim 1,
The low refractive layer is a liquid crystal display device having a refractive index of 1.0 to 1.4.
According to claim 1,
The lower surface light pattern protrudes from the lower surface in a hemi sphere shape, and the height is diameter:height = 1: (0.5±10%).
According to claim 1,
The lower surface emitting light pattern has a cross-section of an inverted trapezoid, protrudes from the lower surface in the form of a column in which the inverted trapezoid is rotated 360°, and has a height of diameter: height = 1: (0.7 ± 10%).
a liquid crystal panel;
a light guide plate located below the liquid crystal panel, having a first light collecting layer on an upper surface corresponding to the back of the liquid crystal panel, and a bottom light emitting pattern on the lower surface;
a reflector located below the light guide plate and including a first diffusion layer, a low refractive index layer having a lower refractive index than the first diffusion layer, and a reflection layer sequentially from the lower surface of the light guide plate;
a light collection sheet located on an upper part of the light guide plate and including a support layer, a second light collection layer disposed on an upper surface of the support layer, and a second diffusion layer disposed on a lower surface of the support layer;
It includes an LED assembly arranged along the light receiving surface of the light guide plate,
The lower surface light pattern protrudes from the lower surface of the light guide plate in the shape of a half prism,
The half-prism shape protruding from the lower surface includes a first inclined surface on a long side facing the LED assembly and a second inclined surface on a short side facing in a direction opposite to the first inclined surface,
A liquid crystal display device wherein the low refractive index layer has a refractive index of 1.0 to 1.4 and the first diffusion layer has a refractive index of 1.5 or more.
According to claim 6,
A liquid crystal display device in which the height of the half prism shape is diameter:height = 1: (0.58±10%).
According to claim 6,
The angle formed by the first inclined surface and the lower surface is 30 (±10) degrees,
The liquid crystal display device wherein the angle formed between the second inclined surface and the lower surface is 75 (±10) degrees.
According to claim 1 or 6,
The first and second light collecting layers are formed in a strip shape with repeated peaks and valleys along a longitudinal direction orthogonal to each other.
According to claim 1 or 6,
The first and second diffusion layers include a light diffusion component including beads or fibers, or are provided with a fine pattern.
According to claim 1 or 6,
A liquid crystal display device comprising a guide panel surrounding an edge of the liquid crystal panel, a cover button configured to be in close contact with the guide panel, and a case top that surrounds an edge of the liquid crystal panel and is assembled and coupled to the guide panel and the cover button.

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