KR20210028932A - Liquid Crystal Display device - Google Patents

Abstract

The present invention relates to a display device, which is light and thin and is capable of achieving picture quality improvement by preventing a stain such as a hot spot. According to the present invention, a backlight unit of the liquid crystal display device includes a glass plate provided with a three-dimensional pattern lens on the back surface and an accommodating groove accommodating an LED in each three-dimensional pattern lens. As a result, the generation of a stain such as a hot spot on the LED can be prevented and a decline in the picture quality of the liquid crystal display device can be prevented. In addition, the configuration of a reflective pattern sheet and a reflective sheet for stain prevention on an LED can be omitted, and thus the device can be light and thin and process cost reduction can be achieved along with convenient assembly.

Description

Display device {Liquid Crystal Display device}

The present invention relates to a display device, and more particularly, to a display device capable of improving image quality by preventing spots such as hot spots while implementing light weight and thinness.

With the recent development of information technology and mobile communication technology, the development of display devices capable of visually displaying information is being made. It is classified as a non-luminous display capable of.

An example of a non-light-emitting type display, which is a device that does not have a self-luminous element, is a liquid crystal display (LCD).

Accordingly, an LCD, which is a non-light-emitting display, requires a separate light source, and a backlight unit having a light source is provided on the rear surface to irradiate light toward the front of the LCD, and through this, an identifiable image is finally realized.

The backlight unit uses a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp, and a light emitting diode (LED, hereinafter referred to as LED) as light sources.

Among them, LEDs, in particular, have features such as small size, low power consumption, and high reliability, and are thus widely used as a display light source.

On the other hand, a general backlight unit is divided into a side light type and a direct light type according to the arrangement structure of the LED as a light source.In the side light type, LEDs are arranged on one side or both sides of the light guide plate. With a structure, the photometric light irradiated from the LED through the light guide plate is converted into flat light, and the liquid crystal panel is irradiated.

In the direct light type, a plurality of LEDs are disposed under the liquid crystal panel to directly irradiate light on the front surface of the liquid crystal panel.

Recently, in a state in which research on a large-area liquid crystal display device has been actively conducted in response to a consumer's request, the direct light type is more suitable for a large-area liquid crystal display device than the side light type.

In addition, the direct light type can improve the uniformity and brightness of light irradiated to the liquid crystal panel, and can implement local dimming driving, thereby improving contrast ratio and reducing power consumption.

However, in the direct light type, since the LED, which is a light source, is disposed under the liquid crystal panel to directly irradiate light to the liquid crystal panel, a mura such as a hot spot occurs on the upper part of the LED, resulting in a problem of deteriorating image quality. Can occur.

An object of the present invention is to provide a liquid crystal display device capable of improving image quality by preventing spots such as hot spots while implementing light weight and thinness.

In order to achieve the object as described above, the present invention provides an LED assembly in which a plurality of LEDs are mounted on a PCB, a glass plate located above the LED assembly, and having a receiving groove in which each of the LEDs is mounted, A display device comprising a liquid crystal panel positioned above the glass plate, the glass plate protruding from a rear surface of a three-dimensional pattern lens having each of the receiving grooves.

In this case, the glass plate protrudes from the rear surface of the support layer and the three-dimensional pattern lenses to be arranged adjacent to each other in the vertical direction and the horizontal direction, and the three-dimensional pattern lens includes a lower surface defined on the rear surface of the support layer, and the lower surface. It includes four or six side surfaces that have an inclination angle in a direction facing each other from a surface and protrude upward and a horizontal surface connecting the four side surfaces, and the horizontal surface has an area smaller than that of the lower surface.

W < P1(LW는 상기 LED의 길이, P1은 이웃하여 위치하는 상기 LED 간의 간격)을 만족하며, 상기 수용홈은 높이(H)와 상기 폭(W)의 비율이 2이다. And, the width (W) of the receiving groove is 1.5LW

W <P1 (LW is the length of the LED, P1 is the distance between adjacent LEDs), and the accommodation groove has a ratio of height (H) and width (W) of 2.

In addition, the height (D2) of the three-dimensional pattern lens is D2 = (P1/2) *tan(90°- ai) + LD (LD is the height of the LED, P1 is the distance between adjacent LEDs, ai is The critical angle at which total reflection does not occur among the light emitted from the LED) is satisfied, and the inclination angle satisfies Tan ^-1 (D2/P2) <a <90°, and Wt/P2 (P2 is (P1-LW)) / 2, Wt satisfies a range in which the width of the horizontal plane around the receiving groove of the three-dimensional pattern lens) is within 0.2 to 0.45.

In addition, an optical sheet is interposed between the liquid crystal panel and the glass plate.

As described above, according to the present invention, the backlight unit of the liquid crystal display device includes a three-dimensional pattern lens on a rear surface and a glass plate having a receiving groove for receiving an LED in each of the three-dimensional pattern lenses. There is an effect that can prevent the same stain from occurring. Through this, there is an effect of preventing the occurrence of a problem of deteriorating the image quality of the liquid crystal display device.

In addition, it is possible to omit the configuration of the reflective pattern sheet and the reflective sheet (=reflective pattern) that were provided to prevent spots such as hot spots from occurring on the upper part of the LED, so that light weight and thinness can be realized. There is an effect that can bring about reduction of process cost and convenience of assembly.

1 is a schematic cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.
Figure 2 is a rear perspective view schematically showing a glass plate according to an embodiment of the present invention.
3 is an enlarged cross-sectional view schematically showing a part of a backlight unit of a modular liquid crystal display device.
4 is a graph defining the height of the receiving groove of the glass plate.
5A to 5B are experimental results of measuring the amount of light emitted from the center of the receiving groove according to the ratio of the height of the receiving groove and the width of the receiving groove of the glass plate.
6A to 6D are experimental data showing images according to Wt/P2.
7 is a schematic diagram schematically showing a path through which light proceeds to a glass plate according to an embodiment of the present invention.
8 is a rear perspective view schematically showing another configuration of a glass plate according to an embodiment of the present invention.

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

1 is a schematic cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

As shown, the liquid crystal display device 100 is composed of a liquid crystal panel 110 and a backlight unit 120. First, the liquid crystal panel 110 is a part that plays a key role in image expression, and the liquid crystal layer is interposed therebetween. It includes the first and second substrates 112 and 114 bonded to each other while facing each other.

At this time, although not clearly shown in the drawing under the premise of the active matrix method, a plurality of gate lines and data lines cross the inner surface of the first substrate 112, which is usually called a lower substrate or an array substrate, so that a pixel is defined. In addition, a thin film transistor (TFT) is provided at each intersection point and is connected to a transparent pixel electrode formed in each pixel in a one-to-one correspondence.

And the inner surface of the second substrate 114 called the upper substrate or the color filter substrate, as an example corresponding to each pixel, is a color filter of red (R), green (G), and blue (B) colors, and these A black matrix is provided surrounding each of the gate lines, data lines, and non-display elements such as thin film transistors. In addition, a transparent common electrode covering them is provided.

In addition, although not clearly shown in the drawing, upper and lower alignment layers (not shown) that determine the initial molecular arrangement direction of the liquid crystal are interposed at the boundary between the two substrates 112 and 114 of the liquid crystal panel 110 and the liquid crystal layer. , In order to prevent leakage of the liquid crystal layer filled therebetween, a seal pattern is formed along the edges of both substrates 112 and 114.

At this time, upper and lower polarizing plates 119a and 119b are attached to outer surfaces of the first and second substrates 112 and 114, respectively.

A backlight unit 120 that supplies light is provided on the rear surface of the liquid crystal panel 110 so that the difference in transmittance indicated by the liquid crystal panel 110 is expressed to the outside.

The backlight unit 120 includes an LED assembly 129, a glass plate 200 and an optical sheet 121 positioned on the LED assembly 129.

The LED assembly 129 includes a plate or a plurality of bar-shaped PCBs 129b, and a plurality of LEDs 129a mounted on each of them.

In order to improve luminous efficiency and luminance, a plurality of LEDs 129a use a blue LED 129a including a blue LED chip having excellent luminous efficiency and luminance, and as a phosphor,'cerium-doped yttrium aluminum garnet (YAG:Ce). )', that is, a blue LED 129a made of a yellow phosphor is used.

The blue light emitted from the LED 129a passes through the phosphor and is mixed with the yellow light emitted by the phosphor, thereby emitting white light toward the glass plate 200.

The glass plate 200 and the optical sheet 121 are sequentially positioned above the LED assembly 129 including a plurality of LEDs 129a, and the glass plate 200 includes the LEDs of the LED assembly 129 ( A configuration in which light incident from 129a is diffused and guided to the entire backlight unit 120, and is made of a glass material.

The glass plate 200 includes a plurality of three-dimensional pattern lenses 210 for supplying a uniform surface light source to the rear, and each three-dimensional pattern lens 210 includes each LED 129a of the LED assembly 129 It is provided with a receiving groove 220 is accommodated. The three-dimensional pattern lens 210 and the receiving groove 220 of the glass plate 200 will be discussed in more detail later.

The optical sheet 121 positioned above the glass plate 200 includes a diffusion sheet and at least one light collecting sheet, and may include various functional sheets such as a reflective polarizing film called a dual brightness enhancement film (DBEF).

The diffusion sheet is positioned directly on the glass plate 200 and includes a base film made of PET and an acrylic resin layer including light diffusion components such as beads on both sides of the base film.

This diffusion sheet serves to adjust the direction of the light so that the light proceeds toward the light collecting sheet while dispersing the light incident through the glass plate 200.

Then, the light diffused by passing through the diffusion sheet by the light collecting sheet is condensed toward the liquid crystal panel 110. Accordingly, most of the light passing through the condensing sheet proceeds perpendicular to the liquid crystal panel 110 to have a uniform luminance distribution.

Therefore, the light emitted from the plurality of LEDs 129a of the LED assembly 129 is processed into uniform high-quality light in the process of passing through the glass plate 200 and the optical sheet 121 in order, and the liquid crystal panel 110 It is incident with a more uniform surface light source.

Here, as above, the backlight unit 120 according to the embodiment of the present invention is a direct light type backlight unit and can implement local dimming for each area of the liquid crystal panel 110, thereby improving the contrast ratio and reducing power consumption. Can be obtained.

As described above, in the liquid crystal display device 100 according to the embodiment of the present invention, the backlight unit 120 is a three-dimensional pattern lens 210 on the rear surface and the LED 129a is accommodated in each of the three-dimensional pattern lens 210. By including the glass plate 200 provided with the receiving groove 220, it is possible to prevent the occurrence of spots such as hot spots above the LED (129a).

Through this, it is also possible to prevent the occurrence of a problem in that the image quality of the liquid crystal display device 100 is deteriorated.

In addition, the configuration of the reflective pattern sheet and the reflective sheet (=reflective pattern), which were provided to prevent spots such as hot spots, from occurring on the top of the LED 129a can be omitted, thereby implementing light weight and thinness. It can also bring about reduction of process cost and convenience of assembly.

2 is a rear perspective view schematically showing a glass plate according to an embodiment of the present invention, and FIG. 3 is an enlarged cross-sectional view schematically showing a part of a backlight unit of a modular liquid crystal display device.

4 is a graph defining the height of the receiving groove of the glass plate.

5A to 5B are experimental results of measuring the amount of light emitted from the center of the receiving groove according to the ratio of the height of the receiving groove and the width of the receiving groove of the glass plate, and FIGS. 6A to 6D are experimental data showing images according to Wt/P2. to be.

As shown in FIG. 2, the glass plate 200 has a configuration that diffuses and guides light incident from the LED 129a of the LED assembly 129 to the entire backlight unit (120 in FIG. 1). It is differentiated in that it is made of glass) material.

That is, polymethyl methacrylate (PMMA), MS (methlystylene) resin, polystyrene (polymethyl methacrylate: PMMA), MS (methlystylene) resin, and polystyrene ( Light guide plates made of light-transmitting plastic materials such as polystyrene:PS), polypropylene (PP), polyethylene terephthalate (PET), and polycarbonate (PC) are widely used. Although the transmittance is high, the thickness of the light guide plate must be at least a certain thickness in order to maintain a certain rigidity, and the plastic light guide plate is characterized by a high coefficient of thermal expansion and moisture swelling.

Accordingly, a display device in which a plastic light guide plate such as PMMA, PC, or PS is used has limitations in slimming, there are limitations in the arrangement of the light guide plate and the LED, or an additional support structure is required.

In order to solve the shortcomings of such a plastic light guide plate, in an embodiment of the present invention, instead of the light guide plate used in the backlight unit (120 in FIG. 1), a glass plate 200 made of a glass material is used from the LED 129a. The incident light is diffused and guided to the entire backlight unit (120 in FIG. 1).

Such a glass plate 200 has an advantage in that it has superior rigidity compared to a plastic light guide plate and can be made thinner, which is advantageous for slimming the display device (100 in FIG. 1), and is advantageous in that it has low thermal expansion and moisture swelling properties.

The glass plate 200 is composed of a support layer 201 and a three-dimensional pattern layer protruding from the rear surface of the support layer 201. The three-dimensional pattern layer is a plurality of three-dimensional pattern lenses 210 and has a plurality of pyramid-shaped tops cut off. The three-dimensional pattern lens 210 is arranged to protrude from the rear surface of the support layer 201.

Accordingly, the plurality of three-dimensional pattern lenses 210 are formed in a shape in which the area decreases as it progresses upward from the lower surface 211 defined on the rear surface of the support layer 201.

That is, for each three-dimensional pattern lens 210, a square lower surface 211 is defined on the rear surface of the support layer 201, and four side surfaces 215 protruding upward from the square lower surface 211, and the lower surface Consists of a horizontal surface 213 that faces parallel to 211 and connects the four side surfaces 215.

At this time, as the four side surfaces 215 protrude upward from the lower surface 211 in a direction facing each other (a, see Fig. 3), the horizontal surface 213 connecting the four side surfaces 215 Is formed to have a smaller area than the lower surface 215.

In the center of each horizontal surface 213 of the three-dimensional pattern lens 210, a receiving groove 220 that is concave toward the lower surface 211 is provided.

The receiving groove 220 may be formed in a dome structure, and each LED 129a of the LED assembly 129 is positioned inside the receiving groove 220.

The plurality of three-dimensional pattern lenses 210 are arranged adjacent to each other in the longitudinal and transverse directions from the rear surface of the support layer 201, and are closely arranged so that there is no empty space between the three-dimensional pattern lenses 210 that are adjacent to each other.

Through this, the glass plate 200 according to the exemplary embodiment of the present invention is defined by being divided into a light diffusion and refraction area (A) and a total reflection area (B).

That is, the light diffusion and refraction area A is defined around the receiving groove 220, and the total reflection area B is defined around the adjacent three-dimensional pattern lenses 210.

Therefore, in the liquid crystal display device (100 in FIG. 1) according to an embodiment of the present invention, there is no need to place a separate reflective pattern sheet between the LED assembly 129 and the optical sheet (121 in FIG. 1), and thus each LED Even if a reflective sheet (= reflective pattern) is not provided between the 129a, it is possible to prevent spots such as hot spots from occurring on the LED 129a.

Through this, since the configuration of the reflective pattern sheet and the reflective sheet (= reflective plate) can be omitted, light weight and thinness can be realized, and process cost can be reduced and assembly convenience is also provided.

This will be described in more detail with reference to FIGS. 3 and 4 attached below.

As shown in FIG. 3, each LED 129a of the LED assembly (129 in FIG. 1) is accommodated into the receiving groove 220 of each three-dimensional pattern lens 210 of the glass plate 200, at this time The width W of the receiving groove 220 is defined by the following (Equation 1).

(Equation 1)

W < P11.5LW

W <P1

In (Equation 1) above, LW is the length of each LED 129a, and 1.5 is the tolerance according to the position of the LED 129a so that there is no interference between the LED 129a and the receiving groove 220. It is a value defined as 1/2 of the length.

That is, it was defined as 1.5LW = LW + LW/2.

W refers to the width of the receiving groove 220, P1 refers to the distance between the adjacent LEDs (129a).

Here, the receiving groove 220 may be formed using a laser. When the receiving groove 220 is formed by using a laser in this way, the receiving groove 220 has a shape of a predetermined curvature in the form of a parabolic surface.

Therefore, since the receiving groove 220 is formed in a dome structure, the height (H) of the receiving groove 220 may be defined as shown in FIG. 4, that is, the height (H) of the receiving groove 220 is It may be defined by the ratio of the width (W) of the receiving groove 220. The following (Table 1) is an experiment result of measuring the amount of light emitted from the central part (area C) of the receiving groove 220 according to the ratio of the height (H) of the receiving groove 220 and the width (W) of the receiving groove 220 to be.

And, Figures 5a ~ 5b is an experiment measuring the amount of light emitted from the central portion (C area) of the receiving groove 220 according to the ratio of the height (H) of the receiving groove 220 and the width (W) of the receiving groove 220 As a result, the attached FIG. 5A measures the outgoing light amount according to the light exit path when the H/W ratio is 1, and FIG. 5B measures the outgoing light amount according to the light exit path when the H/W ratio is 2.

Glass plate W H/W The amount of light emitted from the center of the receiving groove (area C) 1.5LW One 34.6% 1.5 22.2% 2 14.1%

Looking at (Table 1) above, the ratio of the width (W) of the receiving groove 220 and the height (H) of the receiving groove 220 in a state where the width (W) of the receiving groove 220 is fixed at 1.5 LW As this becomes different, it can be seen that a difference occurs in the amount of light emitted from the central portion (region C) of the receiving groove 220. Here, in order to prevent spots such as hot spots from occurring above the LEDs 129a, the amount of light emitted from the central portion (area C) of the receiving groove 220 in which the LEDs 129a are accommodated is preferably adjusted to 15% or less. , It is preferable to form a ratio of the width (W) of the receiving groove (220) and the height (H) of the receiving groove (220) to have 2.

Next, the height (D1) of the support layer 201 of the glass plate 200 may be made of 1 mm as a fixed variable, and the height (D2) of the three-dimensional pattern lens 210 formed by protruding from the rear surface of the support layer 201 ) Can be defined by the following (Equation 2).

(Equation 2)

D2 = (P1/2)*tan(90°- ai) + LD

Here, P1 denotes a distance between adjacent LEDs 129a, and ai denotes a critical angle at which total reflection does not occur among the light emitted from the LEDs 129a accommodated in the receiving groove 220 of the glass plate 200.

And LD represents the height of the LED 129a.

The height (D2) of the three-dimensional pattern lens 210 may allow light emitted from the side of the LED (129a) to be emitted vertically, and the height (H) of the receiving groove 220 in which the LED (129a) is accommodated It is formed higher, so that the light refracted from the receiving groove 220 can also be additionally controlled.

At this time, it is preferable to design the inclination angle α of the side surface 215 of the three-dimensional pattern lens 210 to satisfy the following (Equation 3).

(Equation 3)

Tan ^-1 (D2/P2) <a <90°

Here, P2 may be defined by (P1-LW) / 2.

In addition, it is preferable that the inclination angle α is within a range that satisfies the above (Equation 3), and that Wt/P2 satisfies the range within 0.2 to 0.45.

This can be confirmed by referring to (Table 2) below, and (Table 2) is an experimental result of measuring the amount of light emitted from area D defined on the drawing, which is the periphery of the receiving groove 220 according to Wt/P2.

Glass plate Wt/P2 The amount of light emitted from the periphery of the receiving groove (area D) 0 38.1% 0.2 31.9% 0.45 22.6% 0.7 17.7% One 13.2%

Here, Wt denotes the width of the horizontal plane 213 around the receiving groove 220 of the three-dimensional pattern lens 210, and P2 denotes the width around the receiving groove 220 of the three-dimensional pattern lens 210 of the support layer 201. . When Wt/P2 is 0, it means that there is no horizontal surface 213 of the three-dimensional pattern lens 210, and when Wt/P2 is 1, the side surface 215 is inclined angle (α) from the support layer 201 It means that it is vertically bent and formed without.

At this time, since it is preferable to adjust the amount of light emitted from the peripheral portion (area D) of the receiving groove 220 in which the LED 129a is accommodated, it is desirable to adjust the Wt/P2 to satisfy the range within 0.2 to 0.45. It is desirable.

Therefore, it is desirable to design the inclination angle (a) of the side surface 215 of the three-dimensional pattern lens 210 to satisfy (Equation 3) within the range of 0.2 to 0.45 Wt/P2.

Here, the attached FIGS. 6A to 6D are experimental data showing images according to Wt/P2, and FIG. 6A shows the case where Wt/P2 is 0, FIG. 6B shows the case where Wt/P2 is 0.45, and FIG. 6C shows the Wt/P2. Fig. 6D is experimental data showing an image when P2 is 0.7 and Wt/P2 is 1.

First, referring to FIG. 6A, when the inclination angle (a) of the side surface 215 of the three-dimensional pattern lens 210 is designed to have Wt/P2 of 0, the central portion (C) of the receiving groove 220 in which the LED 129a is located (C It can be seen that the luminance of the area) is lower than that of the peripheral part (area D), and a hot spot occurs above the LED 129a.

In addition, referring to FIGS. 6C and 6D, when the inclination angle (a) of the side surface 215 of the three-dimensional pattern lens 210 is designed to have a Wt/P2 of 0.7 or more, the receiving groove 220 in which the LED 129a is located. ), it can be seen that the luminance is high only in the center (region C) of the receiving groove 220, and in the peripheral portion (region D) of the receiving groove 220, a dark portion is generated due to a decrease in luminance, thereby generating a dark portion.

On the other hand, referring to FIG. 6B, when the inclination angle (a) of the side surface 215 of the three-dimensional pattern lens 210 is designed to have a Wt/P2 of 0.45, a hot spot or a dark grid is not generated, and a uniform luminance is measured forward. Therefore, it can be seen that a uniform surface light source is implemented.

Therefore, it is desirable to design the inclination angle (a) of the side surface 215 of the three-dimensional pattern lens 210 to satisfy (Equation 3) within the range of 0.2 to 0.45 Wt/P2.

In this way, a receiving groove 220 having a width (W) and a height (H) in which the ratio of (Equation 1) and H/W satisfies 2 is designed as the rear surface of the glass plate 200, and a three-dimensional pattern lens The height (D2) of (210) is designed to satisfy (Equation 2), and the inclination angle (a) of the side surface 215 of the three-dimensional pattern lens 210 is within the range of 0.2 ~ 0.45 of Wt/P2. Within the satisfaction, by forming the three-dimensional pattern lens 210 designed to satisfy (Equation 3), the liquid crystal display device (100 in FIG. 1) according to the embodiment of the present invention has a hot spot and a hot spot on the top of the LED 129a. It is possible to prevent the same spots from occurring, and thus, it is possible to prevent the occurrence of a problem in that the image quality of the liquid crystal display (100 in FIG. 1) is deteriorated.

7 is a schematic diagram schematically showing a path through which light proceeds to a glass plate according to an embodiment of the present invention.

As shown, in the liquid crystal display device (100 of FIG. 1) according to the embodiment of the present invention, the glass plate 200 is positioned above the LED assembly (129 of FIG. 1), which is a light source of the backlight unit (120 of FIG. 1). Then, the LEDs 129a of the LED assembly (129 in FIG. 1) are positioned inside each receiving groove 220 of the three-dimensional pattern lens 210 formed on the rear surface of the glass plate 200.

At this time, the receiving groove 220 has a width (W) and a height (H) so that the above-described (Equation 1) and the ratio of H/W to satisfy 2, and the height (D2) of the three-dimensional pattern lens 210 ) Satisfies (Equation 2), and the inclination angle (a) of the side surface 215 of the three-dimensional pattern lens 210 is within the range of 0.2 ~ 0.45 Wt / P2, (Equation 3) Satisfies.

Therefore, the glass plate 200 defines a light diffusion and refraction area A around the receiving groove 220, and also defines a total reflection area B around the adjacent three-dimensional pattern lenses 210. do.

Here, the light diffusion refractive region A around the receiving groove 220 diffuses the light F1 that is emitted vertically among the light emitted from the LED 129a.

That is, the light (F1, F2) emitted from the LED (129a) located inside the receiving groove 220 of the glass plate 200 is incident into the three-dimensional pattern lens 210, the inside of the three-dimensional pattern lens 210 Some of the light (F1, F2) incident to the light (F1) proceeds as it is without refraction and is emitted to the central portion (region C) of the receiving groove 220.

In this case, the amount of light F1 emitted to the front of the three-dimensional pattern lens 210 as it is without refraction is within about 15%.

In addition, some light F2 is diffused and refracted by the boundary of the receiving groove 220, that is, the light F2 incident at the boundary of the receiving groove 220 below the critical angle is the boundary of the receiving groove 220 It diffuses and refracts in the process of passing through.

Accordingly, some light F2 is emitted to the periphery of the receiving groove.

In addition, the light F3 incident on the boundary of the receiving groove 220 at a critical angle or more is totally reflected to the front of the three-dimensional pattern lens 210 of the total reflection area B through the side surface 215 of the three-dimensional pattern lens 210. It is emitted, and is emitted to the periphery between the three-dimensional pattern lenses 210 positioned adjacent to each other.

At this time, the outgoing amount of light diffused and refracted by the boundary of the receiving groove 220 and the total reflected light F3 is about 50 to 70%.

Therefore, the light (F1, F2) emitted to the central portion (C) of the receiving groove 220 of the three-dimensional pattern lens 210 and the light (F3) emitted to the periphery (D) between the three-dimensional pattern lens 210 positioned adjacent to each other All have uniform luminance.

That is, among the light (F1, F2, F3) emitted from the LED (129a), the central portion (C) of the three-dimensional pattern lens 210, that is, the light (F1, F2) concentrated to the central portion (C) of the receiving groove 220 The receiving groove 220 is dispersed between the peripheral portion D and the three-dimensional pattern lens 210 positioned adjacent to each other, so that the left and right luminance is increased around the three-dimensional pattern lens 210 and has a wide beam angle.

As described above, in the liquid crystal display device (100 of FIG. 1) according to the embodiment of the present invention, the backlight unit (120 of FIG. 1) is a three-dimensional pattern lens 210 on the rear surface and an LED on each of the three-dimensional pattern lenses 210. By including the glass plate 200 provided with the receiving groove 220 in which the 129a is accommodated, it is possible to prevent the occurrence of spots such as hot spots above the LED 129a.

Through this, it is also possible to prevent a problem that the image quality of the liquid crystal display (100 in FIG. 1) deteriorate.

In addition, since the configuration of the reflective pattern sheet and the reflective sheet (=reflective pattern) provided to prevent spots such as hot spots from occurring on the upper part of the LED 129a can be omitted, it is possible to implement light weight and thinness through this, In addition, process cost reduction and assembly convenience can also be brought.

8 is a rear perspective view schematically showing another configuration of a glass plate according to an embodiment of the present invention.

As shown, the glass plate 200 is made of a support layer 201 and a three-dimensional pattern layer protruding from the rear surface of the support layer 201, and the three-dimensional pattern layer is a hexagonal lower surface 231 on the rear surface of the support layer 201. ) Is defined, and consists of six side surfaces 235 protruding upward from the lower surface 231 and a horizontal surface 233 that faces parallel to the lower surface 231 and connects the six side surfaces 235 It includes a pattern lens 230.

At this time, as the six side surfaces 235 protrude upward at a certain angle in a direction facing each other from the lower surface 231, the horizontal surface 233 connecting the six side surfaces 235 is more than the lower surface 231. It is formed to have a small area.

In the center of each horizontal surface 233 of the three-dimensional pattern lens 230, a receiving groove 220 that is concave toward the lower surface 231 is provided, and the receiving groove 220 may be formed in a dome structure. (220) Each LED (129a of FIG. 7) of the LED assembly (129 of FIG. 3) is located inside.

The plurality of three-dimensional pattern lenses 230 are arranged adjacent to each other in the vertical and horizontal directions from the rear surface of the support layer 201, and are closely arranged so that there is no empty space between the three-dimensional pattern lenses 230 adjacent to each other.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.

129: LED assembly (129a: LED, 129b: PCB)
200: glass plate (201: support layer, 210: three-dimensional pattern lens, 220: receiving groove)

Claims (8)

An LED assembly in which a plurality of LEDs are mounted on a PCB;
A glass plate positioned above the LED assembly and provided with a receiving groove in which each of the LEDs is mounted;
Liquid crystal panel located above the glass plate
Including,
The glass plate is a display device in which the three-dimensional pattern lenses each having the receiving grooves protrude toward the rear surface thereof.
The method of claim 1,
The glass plate protrudes from a rear surface of the support layer and the three-dimensional pattern lenses to be arranged adjacent to each other in a longitudinal direction and a transverse direction.
The method of claim 2,
The three-dimensional pattern lens includes a lower surface defined on a rear surface of the support layer, and a horizontal surface connecting the four side surfaces with four or six side surfaces protruding upward and having an inclination angle in a direction facing each other from the lower surface, and ,
The horizontal surface has a smaller area than the lower surface.
The method of claim 3,
The width (W) of the receiving groove is 1.5LW

A display device satisfying W <P1 (LW is the length of the LED, and P1 is the distance between adjacent LEDs).
The method of claim 4,
The receiving groove has a height (H) and a width (W) of 2 in a display device.
The method of claim 3,
The height (D2) of the three-dimensional pattern lens is D2 = (P1/2)*tan(90°- ai) + LD (LD is the height of the LED, P1 is the distance between adjacent LEDs, ai is the LED A display device that satisfies the critical angle at which total reflection does not occur among the light emitted from the light.
The method of claim 3,
The inclination angle ^{satisfies Tan -1} (D2/P2) <a <90°, and Wt/P2 (P2 is (P1-LW) / 2, Wt is the width of the horizontal plane around the receiving groove of the three-dimensional pattern lens) ) Is within the range of 0.2 to 0.45.
The method of claim 1,
An optical sheet is interposed between the liquid crystal panel and the glass plate.

Images