KR101347163B1 - Liquide crystal display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device which can easily perform the fastening of a printed circuit board on which the light emitting diode is mounted while increasing the mixing ratio of light emitted from a light emitting diode provided as a light source. will be. The present invention relates to a liquid crystal panel, At least one light emitting diode array arranged in one direction under the liquid crystal panel to supply light to the liquid crystal panel; At least one printed circuit board on which the light emitting diode array is mounted; A lower cover accommodating the printed circuit board; A diffusion member disposed on an upper portion of the light emitting diode array and mixing light emitted from the light emitting diode array; First reflecting members disposed at sides of the light emitting diode arrays arranged in a row to reflect light emitted from the light emitting diode arrays toward the diffusion member; Lt; / RTI > In addition, the present invention includes a printed circuit board fixing means extending from the inside of the lower cover and having a shape surrounding a portion of the first reflective member and the diffusion member.

Liquid crystal displays, light emitting diodes

Description

[0001] LIQUIDE CRYSTAL DISPLAY DEVICE [0002]

1 is a sectional view showing a general liquid crystal display device.

FIG. 2 is a plan view illustrating a printed circuit board on which the lower cover and the light emitting diode of FIG. 1 are mounted.

3 is a cross-sectional view illustrating a liquid crystal display device according to a first embodiment of the present invention.

4 is an enlarged perspective view of a portion of the liquid crystal display of FIG. 3.

5 is a cross-sectional view showing a liquid crystal display device according to a second embodiment of the present invention.

FIG. 6 is an enlarged perspective view of a portion of the liquid crystal display of FIG. 5. FIG.

7 is a cross-sectional view showing a liquid crystal display device according to a third embodiment of the present invention.

FIG. 8 is an enlarged perspective view of a portion of the liquid crystal display of FIG. 7. FIG.

9 is a cross-sectional view showing a liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 10 is an enlarged perspective view of a portion of the liquid crystal display of FIG. 9; FIG.

DESCRIPTION OF REFERENCE NUMERALS

102,202,302,402: Light Emitting Diode Array

102a, 202a, 302a, 402a: light emitting diodes 103, 203, 303, 403: printed circuit board

104, 204, 304, 404: lower cover 104a, 204a, 304a, 404a: printed circuit board fixing means

105,205,305,405: Diffusion member 205c, 405c: Fastening groove

105a, 205a, 305a, 405a: light emitting surface 105b, 205b, 305b, 405b: light emitting surface

106,206: first reflective member 116,216: second reflective member 316,416: reflective member

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device which can easily perform the fastening of a printed circuit board on which the light emitting diode is mounted while increasing the mixing ratio of light emitted from a light emitting diode provided as a light source. will be.

Generally, the liquid crystal display device has a tendency of widening its application range due to features such as light weight, thinness, and low power consumption driving. Accordingly, liquid crystal display devices are widely used as portable computers such as notebook PCs, office automation devices, and audio / video devices.

In general, a liquid crystal display device displays a desired image on a screen by controlling a light transmission amount according to a video signal applied to a plurality of switching elements for control arranged in a matrix form.

The liquid crystal display includes a liquid crystal panel in which a color filter substrate as an upper substrate and a thin film transistor array substrate as a lower substrate are opposed to each other, and a liquid crystal layer is filled therebetween; And a liquid crystal panel driver for supplying scan signals and image information to the liquid crystal panel to operate the liquid crystal panel.

Since the liquid crystal display is a non-light emitting device that does not emit light by itself compared to a cathode ray tube (CRT) or a light emitting diode (LED), a backlight assembly that supplies light to a liquid crystal panel to implement an image. (back light assembly).

Light sources of the backlight assembly include a linear light source and a point light source. A typical line light source is a cold cathode fluorescent lamp (CCFL), and a representative point light source is a light emitting diode.

Conventionally, a cold cathode fluorescent lamp is mainly used as a light source of a backlight assembly. However, in recent years, a liquid crystal display device employing a light emitting diode, which is advantageous in power consumption, weight, and luminance, is used as a light source of a backlight assembly according to the trend toward miniaturization, thinness, and light weight of liquid crystal display devices. Is growing.

Hereinafter, a general liquid crystal display device will be described with reference to the accompanying drawings.

1 is a cross-sectional view illustrating a general liquid crystal display, and FIG. 2 is a plan view illustrating a printed circuit board on which the lower cover and the light emitting diode of FIG. 1 are mounted.

As shown in FIG. 1, a general liquid crystal display device includes a liquid crystal panel 1; A light emitting diode (2) positioned below the liquid crystal panel (1) to supply light to the liquid crystal panel (1); At least one printed circuit board 3 on which the light emitting diodes 2 are mounted; A lower cover 4 in which the printed circuit board 3 is accommodated; A light guide plate 9 disposed above the light emitting diodes 2 to mix light emitted from the light emitting diodes 2; An optical sheet (7) disposed on the light guide plate (9) to guide light toward the liquid crystal panel (1) after converting light emitted from the light guide plate (9); .

On the printed circuit board 3, light emitting diodes 2 emitting red, green and blue light are alternately arranged. Here, the light emitting diodes 2 emitting red, green and blue light are individually mounted on the printed circuit board 3, or the light emitting diodes 2 emitting red, green and blue light are grouped together. It is mounted on the printed circuit board 3 in the form of an element of. Also, in recent years, a light emitting diode 2 emitting white light has been devised so that a light emitting diode 2 emitting white light may be mounted on a printed circuit board 3.

That is, the light emitted from the various types of light emitting diodes 2 is converted into high purity and uniform white light through the light guide plate 9 and the optical sheet 7 and then supplied to the liquid crystal panel 1.

However, since the light emitted from the light emitting diodes 2 is not sufficiently mixed inside the light guide plate 9, there is a problem that the user of the liquid crystal display device is observed in the form of color mixing irregularity or bright point.

In order to solve this problem, a method has been devised such as providing a light guide plate having a thick thickness or securing a sufficient distance between the light guide plate and the light emitting diode. However, such a method has recently become smaller and thinner due to the increased thickness of the liquid crystal display device. There is a problem that goes against the trend.

On the other hand, a plurality of the printed circuit board 3 mounted with the light emitting diodes 2 is provided as shown in Figure 2, the printed circuit board 3 is fixed to the lower cover through a screw or the like means. That is, as shown in area A of FIG. 2, the screw is fastened to the fastening holes provided in the printed circuit board 3 and the lower cover 4, so that the printed circuit board 3 is fastened to the lower cover.

However, the liquid crystal display device having the fixed structure as described above requires fastening screws to a plurality of fastening holes provided in the printed circuit board 3 and the lower cover 4, so that the assembly time is long and the overall manufacturing time of the liquid crystal display device is long. There is a problem, and there is a problem that a guide means for easily fastening the screw to the fastening hole is required separately.

The present invention is to solve the above problems, an object of the present invention is to maximize the mixing ratio of the light emitted from the light emitting diode and at the same time the liquid crystal display that can easily perform the fastening of the printed circuit board mounted with the light emitting diode To provide a device.

The present invention for achieving the above object is a liquid crystal panel; At least one light emitting diode array arranged in one direction under the liquid crystal panel to supply light to the liquid crystal panel; At least one printed circuit board on which the light emitting diode array is mounted; A lower cover accommodating the printed circuit board; A diffusion member disposed on an upper portion of the light emitting diode array and mixing light emitted from the light emitting diode array; First reflecting members disposed at sides of the light emitting diode arrays arranged in a row to reflect light emitted from the light emitting diode arrays toward the diffusion member; .

In addition, the present invention includes a printed circuit board fixing means extending from the inside of the lower cover and having a shape surrounding a portion of the first reflective member and the diffusion member.

Hereinafter, a liquid crystal display according to the present invention will be described with reference to the accompanying drawings.

≪ Embodiment 1 >

First, the liquid crystal display according to the first embodiment of the present invention will be described with reference to FIGS. 3 and 4 as follows.

3 is a cross-sectional view illustrating a liquid crystal display device according to a first embodiment of the present invention.

FIG. 4 is an enlarged perspective view of a portion of the liquid crystal display of FIG. 3. For convenience of description, only a part corresponding to a part of one LED array is shown.

As shown in FIG. 3, the liquid crystal display according to the first embodiment of the present invention includes a liquid crystal panel 100; At least one light emitting diode array 102 arranged in one direction under the liquid crystal panel 100 to supply light to the liquid crystal panel 100; At least one printed circuit board 103 on which the light emitting diode array 102 is mounted; A lower cover 104 in which the printed circuit board 103 is accommodated; A diffusion member 105 disposed on each of the light emitting diode arrays 102 to mix light emitted from the light emitting diode arrays 102; First reflecting members (106) disposed at sides of the light emitting diode arrays (102) arranged in a row to reflect light emitted from the light emitting diode arrays (102) toward the diffusion member (105); . Here, the diffusion member 105 is formed on the first reflective member 106.

In addition, the liquid crystal display according to the first exemplary embodiment of the present invention extends from the inside of the lower cover 104 and has a shape surrounding a portion of the first reflective member 106 and the diffusion member 105. Fixing means 104a are provided.

As shown in FIG. 2, the liquid crystal panel 101 includes a first substrate 101a that is a color filter substrate and a second substrate 102b that is a thin film transistor array substrate, and the first substrate 101a and the second substrate. A liquid crystal layer (not shown) is formed between the substrates 101b.

As shown in FIG. 2, the light emitting diode 102a is disposed under the liquid crystal panel 101 to supply light to the liquid crystal panel 101.

As described above, there are three kinds of light emitting diodes 102a provided as a light source of a liquid crystal display device.

The first is a light emitting diode 102a which emits red, green and blue light, which are alternately arranged on the printed circuit board 103 so that the red, green and blue light is diffused to the diffusion member 105 and the first and the first light. 2 is converted into white light by mixing in the space formed by the reflecting members 106 and 116 and then supplied to the liquid crystal panel 101 via the optical sheet 107.

The second is a light emitting diode 102a that emits red, green, and blue light as in the first case, but three light emitting diodes emitting red, green, and blue light are formed as a single device. After the red, green, and blue light is mixed and converted into white light, the optical sheet 107 is converted into a uniform white surface light source in the space formed by the diffusion member 105 and the first and second reflecting members 106 and 116. ) Is supplied to the liquid crystal panel.

The third is the light emitting diode 102a which emits white light, and since the red, green, and blue light do not need to be considered as in the case of the first or second light emitting diode 102a, the liquid crystal display device. There is an advantage that the optical design of the light source is easy.

The light emitting diodes 102a included in the liquid crystal display according to the present invention may be not only the three kinds of light emitting diodes 102a but also other kinds of light emitting diodes within the scope of the present invention.

Such light emitting diodes 102a are arranged in a row on a plurality of printed circuit boards 103.

In the description of the present invention, a bundle of light emitting diodes 102a arranged in a line on one printed circuit board 103 is referred to as a light emitting diode array 102. That is, the light emitting diodes 102a included in the liquid crystal display according to the present invention are formed of a plurality of light emitting diode arrays 102.

As shown in FIG. 3 and FIG. 4, the printed circuit board 103 is provided inside the lower cover 104, and the printed circuit board 103 corresponds to one of the light emitting diode arrays 102.

However, the printed circuit board 103 according to the present invention is not limited to a case in which each light emitting diode array 102 corresponds to one line, and the printed circuit board 103 is within the scope not departing from the gist of the present invention. The light emitting diode array 102 may correspond to a plurality of rows.

In addition, a second reflective member 116 is coated or attached to an upper surface of the printed circuit board 103, and the second reflective member 116 reflects light emitted from the light emitting diode array 102 to diffuse the member. 105) or first reflective member 106.

As shown in FIGS. 3 and 4, the diffusion member 105 is provided for each upper portion of the printed circuit board 103 on which the light emitting diode array 102 is mounted, and covers the upper portion of the light emitting diode array 102a. In addition, the diffusion member 105 is positioned above the first reflection member 106, and a part of the diffusion member 105 contacts the upper surface or the side surface of the first reflection member 106. Such a diffusion member 105 mixes the light emitted from the light emitting diode array (102).

In the accompanying drawings, an end of the rear surface of the diffusion member 105 contacts the end of the first reflective member 106 and is positioned above the light emitting diode array 102, and at the same time, an upper portion of the light emitting diode array 102 is disposed. Although the cover is taken as an example, the present invention is not limited thereto, and the diffusion member 105 has a side surface or an upper surface thereof contacting the first reflective member 106 within a range not departing from the gist of the present invention. While being positioned on the top of the 102, various examples, such as covering the top of the light emitting diode array 102 is possible.

Further, in the accompanying drawings, the shape of the diffusion member 105 has a plate shape parallel to the printed circuit board 103 on which the light emitting diode array 102 is mounted, but the present invention is not limited thereto. The shape of the diffusion member 105 in a range not departing from the gist of the invention may be various examples such as a curved shape having a predetermined curvature.

The diffusion member 105 is polymethylmethacrylate (PMMA), polyethylene terephtalate (PET), poly stylene (PS), acrylonitrile styrene copolymer (AS), meta stylene (MS), polymethylpentene (PMP), polycarbonate (PC), It is made of plastic material with higher refractive index than air, such as cyclic olefin copolymer (COC).

As mentioned above, the first reflective member 106 positioned below the diffusion member 105 starts from the end or side of the top surface of the printed circuit board 103 in which the light emitting diode array 102 is arranged in a line. It has a shape extending to the end or side of the back of the diffusion member 105.

In more detail, the first reflective member 106 is disposed on the side of the light emitting diode array 102 arranged in a line on the printed circuit board 103. Here, the first reflecting member 106 has a predetermined angle with respect to the upper surface of the printed circuit board 103, which is appropriately designed within the range that can lead to efficient mixing of the light emitted from the light emitting diode 102a. Apply.

3 and 4, a printed circuit board for fastening and fixing the printed circuit board 103, the diffusion member 105, and the first reflective member 106 to the inside of the lower cover 104. Fixing means 104a is provided, and the printed circuit board fixing means 104a has a shape surrounding a part of the printed circuit board 103 assembled with the first reflective member 106 and the diffusion member 105, Have elasticity.

In more detail, the printed circuit board fixing means 104a extends from the bottom surface of the lower cover 104. In addition, the printed circuit board fixing means 104a is formed in two pairs, and the pair of the printed circuit board fixing means 104a has a shape in which the front and rear sides are symmetrical with respect to the light emitting diode 102a. Further, when the pair of printed circuit board fixing means 104a is engaged with the printed circuit board 103 assembled with the first reflecting member 106 and the diffusing member 105, the side of the first reflecting member 106 contacts with the side surface of the first reflecting member 106. The portion is preferably equal to the degree of inclination of the outer surface of the first reflecting member 106 with respect to the upper surface of the printed circuit board 103, the portion that does not abut the side of the first reflecting member 106 is a pair It has a shape bent toward the opposite printed circuit board fixing means 104a.

The process of fastening the printed circuit board 103 assembled with the first reflective member 106 and the diffusion member 105 to the printed circuit board fixing means 104a will be described below.

First, the printed circuit board 103 assembled with the first reflective member 106 and the diffusion member 105 is positioned on the plurality of printed circuit board fixing means 104a formed in pairs. Next, the printed circuit board 103 assembled with the first reflective member 106 and the diffusion member 105 is fastened by applying a predetermined pressure toward the space formed by the printed circuit board fixing means 104a.

As a result, the printed circuit board 103 assembled with the first reflective member 106 and the diffusion member 105 is fixed to the lower cover 104.

Here, since the printed circuit board fixing means 104a has elasticity, the printed circuit board 103 assembled with the first reflector member 106 and the diffusion member 105 is attached to the printed circuit board fixing means 104a. During the fastening process, the printed circuit board fixing means 104a is bent outward by the widths of the printed circuit board 103, the first reflecting member 106 and the diffusing member 105, after which the printed circuit board is fixed. When the 103, the first reflecting member 106 and the diffusing member 105 are completely fastened to the printed circuit board fixing means 104a, the printed circuit board fixing means 104a is returned to its original position, thereby printing. The first reflecting member 106 and the diffusing member 105 including the circuit board 103 are firmly fastened to the printed circuit board fixing means 104a.

In the liquid crystal display device having the configuration as described above, the light emitted from the light emitting diode 102a is formed inside the diffusion member 105, the first reflecting member 106 and the second reflecting member 116. In the following description, a process of efficiently mixing and converting into uniform white light is described below.

The light emitted from the light emitting diode 102a is emitted from all the light emitting diodes 102a provided in the liquid crystal display device until the light is emitted to the outside of the diffusion member 105 through the light emitting surface 106a of the diffusion member 106. The light is not mixed with the light, but is mixed with the light emitted from the light emitting diode 102a mounted on the printed circuit board 103 on which the light emitting diode 102a itself is mounted.

The light emitted from the light emitting diode 102a does not exist only in the light traveling in the vertical direction when the liquid crystal panel 101 is used as a reference. In addition, the light emitted from the light emitting diode 102a includes light having an incident angle of less than or equal to a critical angle when the incident light enters the light incident surface 105b of the diffusion member 105. Here, the critical angle is the minimum value of the incident angle at which total reflection of light is possible.

Accordingly, light incident on the light incident surface 105b of the diffusion member 105 at an incident angle below the critical angle among the light emitted from the light emitting diode array 102 enters the interior of the diffusion member 105 and then exits the light exit surface 105a. The light emitted through the light incident on the light incident surface 105b of the diffusion member 105 is totally reflected. As such, the light totally reflected on the light incident surface 105b of the diffusion member 105 is reflected when it proceeds to the first reflection member 106 and the second reflection member 116 and is incident on the light incident surface 105b of the diffusion member 105. If the incident light is incident at a critical angle greater than or equal to a critical angle, the total reflection is performed. When the light proceeds to an incident angle of less than or equal to a critical angle on the light incident surface 105b of the diffusing member 105, the interior of the diffusing member 105 After entering the light exits to the outside of the diffusion member 105 through the light exit surface (105a).

Accordingly, the light emitted from the light emitting diode array 102 is totally reflected several times in the space formed by the diffusion member 105, the first reflecting member 106, and the second reflecting member 116. Are mixed.

That is, when the light emitting diode 102a is an individual light emitting diode 102a emitting red, green and blue light, the diffusion member 105, the first reflecting member 106 and the second reflecting member 116 After the light is converted into pure white light in the space, it is emitted to the outside of the diffusion member 105. In addition, when the light emitting diode 102a is a device having three light emitting diodes 102a emitting red, green, and blue light, the diffusion member 105 and the first reflective member 106 may be used. And converted into more uniform white light in the space formed by the second reflecting member 116 and exit to the outside of the diffusion member 105. In the case where the light emitting diode 102a is a light emitting diode 102a emitting white light, the light emitting diode 102a may be curved in a space formed by the diffusion member 105, the first reflecting member 106, and the second reflecting member 116. After the point is converted into uniform white light having no point, it is emitted to the outside of the diffusion member 105.

As described above, the liquid crystal display according to the first exemplary embodiment of the present invention has the effect of increasing the mixing ratio of the light emitted from the light emitting diode by providing the diffusion member 105 and the first reflective member 106. In addition, the liquid crystal display device according to the first embodiment of the present invention is provided with a printed circuit board fixing means 104a to assemble with the diffusion member 105 and the first reflective member 106 during the assembly process of the liquid crystal display device. The fastening of the printed circuit board 103 can be easily performed without a separate guide means.

≪ Embodiment 2 >

Hereinafter, a liquid crystal display according to a second exemplary embodiment of the present invention will be described with reference to FIGS. 5 and 6.

5 is a cross-sectional view illustrating a liquid crystal display device according to a second embodiment of the present invention.

FIG. 6 is an enlarged perspective view of a part of the liquid crystal display of FIG. 5, and shows only a part corresponding to a part of one LED array for convenience of description.

Since the second embodiment of the present invention is the same as the first embodiment except for the diffusion member, the description of the second embodiment of the present invention will be omitted.

As shown in FIG. 5, the liquid crystal display according to the second exemplary embodiment of the present invention includes a liquid crystal panel 201; At least one light emitting diode array 202 arranged in one direction under the liquid crystal panel 201 to supply light to the liquid crystal panel 201; At least one printed circuit board 203 on which the light emitting diode array 202 is mounted; A lower cover 204 in which the printed circuit board 203 is accommodated; A diffusion member 205 disposed above the light emitting diode array 202 and mixing light emitted from the light emitting diode array 202; First reflecting members (206) disposed at side portions of the light emitting diode arrays (202) arranged in a row to reflect light emitted from the light emitting diode arrays (202) toward the diffusion member (205); . Here, the diffusion member 205 has a shape extending from the upper surface of the printed circuit board 203 to the upper end of the first reflective member 206.

In addition, the liquid crystal display according to the second exemplary embodiment of the present invention extends from the inside of the lower cover 204 and has a shape surrounding a portion of the first reflective member 206 and the diffusion member 205. Fixing means 204a is provided, and a second reflecting member 216 is provided on an upper surface of the printed circuit board 203. The optical sheet 207 is provided on the diffusion member 205.

As shown in FIGS. 5 and 6, the diffusion member 205 is provided for each upper portion of the printed circuit board 203 on which the light emitting diode array 202 is mounted, and the diffusion member 205 is provided with the corresponding light emitting diode. The light emitted from the array 202 is mixed.

The diffusion member 205 is formed in an internal space formed by the first reflective member 206 formed for each LED array 202.

In more detail, the diffusion member 205 is provided with a fastening groove 205c corresponding to the light emitting diode 202a constituting the light emitting diode array 202 and fastened with the light emitting diode 202a, and the fastening groove 205c. Except for the overall shape is a bar shape that is fastened to the inner space formed by the first reflective member 206.

In the accompanying drawings, the fastening groove 205c provided in the diffusion member 205 is the same as the size of the light emitting diode 202a, so that when the light emitting diode 202a is engaged with the light emitting diode 202a as an example, the present invention The fastening groove 205c may be larger than the light emitting diode 202a without departing from the gist of the present invention.

In the accompanying drawings, the light emitting surface 205a of the diffusion member 205 is a plane parallel to the top surface of the printed circuit board 203 on which the light emitting diode array 202a is mounted. The light emitting surface 205a of the diffusion member 205 may have various curvatures, such as a curved shape, without departing from the scope of the present invention.

The diffusion member 205 may be polymethylmethacrylate (PMMA), polyethylene terephtalate (PET), poly stylene (PS), acrylonitrile styrene copolymer (AS), meta stylene (MS), polymethylpentene (PMP), polycarbonate (PC), It is made of plastic material with higher refractive index than air, such as cyclic olefin copolymer (COC).

In the liquid crystal display device having the configuration as described above, a process of efficiently mixing the light emitted from the light emitting diodes 202a will be described.

The light emitted from the light emitting diodes 202a is emitted from all the light emitting diodes 202a of the liquid crystal display until the light is emitted to the outside of the diffusion member 205 through the light emitting surface 205a of the diffusion member 205. The light is not mixed with the light, but is mixed with the light emitted from the light emitting diode 202a mounted on the printed circuit board 203 on which the light emitting diode 202a is mounted.

Since there is almost no space between the fastening hole 205c of the diffusion member 205 and the light emitting diode 202a, most of the light emitted from the light emitting diode 202a is directed to the light incident surface 205b of the diffusion member 205. It is incident inside through.

Accordingly, the light that is emitted from the light emitting diode array 202 and then enters the diffusion member 205 proceeds to the light exit surface 205a of the diffusion member 205 at an angle less than or equal to the threshold angle. The light exiting to the light exit surface 205a of the diffusion member 205 and proceeding at an angle greater than or equal to the critical angle is totally reflected on the light exit surface 205a and the light traveling to the first reflecting member 206 is reflected member 206. Reflected on the surface of the. As such, the light totally reflected on the light exit surface 205a of the diffusion member 205 or reflected on the surface of the first reflective member 206 is applied to the light exit surface 205a of the diffusion member 205 inside the diffusion member 205. The process of total reflection or reflection on the surfaces of the first and second reflective members 206 and 216 is repeated, and the light propagating at an angle below the critical angle with respect to the light exit surface 205a of the diffusion member 205 is reflected by the diffusion member 205. It is emitted to the outside.

Accordingly, the light emitted from the light emitting diode array 202 is totally reflected several times inside the diffusion member 205, so that the light is efficiently mixed.

That is, when the light emitting diodes 202a are individual light emitting diodes emitting red, green, and blue light, the light emitting diodes 202a are converted into pure white light inside the diffusion member and then emitted to the outside of the diffusion member 205. In addition, in the case where the light emitting diode 202a is a device having three light emitting diodes emitting red, green, and blue light, the light emitting diode 202a is diffused after being converted into more uniform white light inside the diffusion member 205. It exits to the outside of the member 205. In the case where the light emitting diode 202a is a light emitting diode emitting white light, the light emitting diode 202a is converted into uniform white light having no bright spot inside the diffusion member 205 and then exits to the outside of the diffusion member 205. do.

As described above, the liquid crystal display according to the second exemplary embodiment of the present invention includes the diffusion member 205 and the first reflecting member 206 to increase the mixing ratio of the light emitted from the light emitting diode 202a. have. In addition, the liquid crystal display device according to the second embodiment of the present invention includes a printed circuit board fixing means 204a so as to be assembled with the diffusion member 205 and the first reflective member 206 during the assembly process of the liquid crystal display device. The fastening of the printed circuit board 203 can be easily performed without a separate guide means.

≪ Third Embodiment >

Hereinafter, a liquid crystal display according to a third exemplary embodiment of the present invention will be described with reference to FIGS. 7 and 8.

7 is a cross-sectional view illustrating a liquid crystal display device according to a third embodiment of the present invention.

FIG. 8 is an enlarged perspective view of a part of the liquid crystal display of FIG. 7, and shows only a part corresponding to a part of one LED array for convenience of description.

In describing the third embodiment of the present invention, the same description as in the first and second embodiments will be omitted.

As shown in FIG. 7, the liquid crystal display according to the third embodiment of the present invention comprises: a liquid crystal panel 301; At least one light emitting diode array 302 arranged in one direction below the liquid crystal panel 301 to supply light to the liquid crystal panel 301; At least one printed circuit board 303 on which the light emitting diode array 302 is mounted; A lower cover 304 in which the printed circuit board 303 is accommodated; The light emitting diode array 302 has a shape surrounding the top and side and comprises a diffusion member 305 for mixing the light emitted from the light emitting diode array 302. Here, the diffusion member 305 is provided with a light incident surface 305b and the light exit surface 305a, the light incident surface 305b and the light exit surface 305a is a curved surface having a predetermined curvature.

In addition, the liquid crystal display according to the third embodiment of the present invention is provided with a printed circuit board fixing means 304a extending from the inside of the lower cover 304 and having a shape surrounding a part of the diffusion member 305. The reflective member 316 is provided on the printed circuit board 303. The optical sheet 307 is provided on the diffusion member 305.

As shown in FIGS. 7 and 8, the diffusion member 305 is provided in a shape surrounding the top and sides of the light emitting diode array 302 for each printed circuit board 303 on which the light emitting diode array 302 is mounted. The diffusion member 305 mixes the light emitted from the light emitting diode array 302.

The diffusion member 305 extends from one side of the printed circuit board 303 to the other side of the printed circuit board 303 with a predetermined curvature so as to be positioned on the side and top of the LED array 302. At the same time to cover the side and top of the light emitting diode array (302).

In the accompanying drawings, the diffusion member 305 extends from the side of the printed circuit board 303 to the other side of the printed circuit board 303 with a predetermined curvature so that the sides and the top of the light emitting diode array 302 are provided. Although the present invention is not limited thereto, the diffusion member 305 may have a predetermined curvature starting from one end of the upper surface of the printed circuit board 303 without departing from the gist of the present invention. By extending to the other end of the upper surface of the printed circuit board 303, various examples such as covering the side and the top of the light emitting diode array 302 is possible.

Further, in the accompanying drawings, the light entering surface 305b and the light emitting surface 305a of the diffusion member 305 both have a predetermined curvature, but the present invention is not limited thereto, and the present invention is not limited to the present invention. Various examples are possible, such that only one of the light entering surface 305b and the light exiting surface 305a of the diffusion member 305 has a curvature within a range that does not exist.

The diffusion member 305 is polymethylmethacrylate (PMMA), polyethylene terephtalate (PET), poly stylene (PS), acrylonitrile styrene copolymer (AS), meta stylene (MS), polymethylpentene (PMP), polycarbonate (PC), It is made of plastic material with higher refractive index than air, such as cyclic olefin copolymer (COC).

In the liquid crystal display device having the configuration as described above, a process of efficiently mixing the light emitted from the light emitting diode 302a will be described.

The light emitted from the light emitting diode 302a is emitted from all the light emitting diodes 302a provided in the liquid crystal display device until the light is emitted to the outside of the diffusion member 305 through the light emitting surface 305a of the diffusion member 305. The light is not mixed with the light, but is mixed with the light emitted from the light emitting diode 302a mounted on the printed circuit board 303 on which the light emitting diode 302a itself is mounted.

The light emitted from the light emitting diode 302a does not exist only in the light traveling in the vertical direction when the liquid crystal panel 301 is used as a reference, and light also travels in a predetermined slope. In addition, the light emitted from the light emitting diode 302a travels with an angle smaller than the critical angle with respect to the light incident surface 305b of the diffusion member 305 and an angle traveling with an angle greater than the critical angle with respect to the light incident surface 305b. This exists.

Therefore, the light incident from the light emitting diode array 302 to the light incident surface 305b of the diffusion member 305 at an angle of incidence below the critical angle is incident on the inside of the diffusion member 305 and then the light exit surface 305a. The light emitted to the outside of the diffusion member 305 and incident on the light incident surface 305b of the diffusion member 305 at an incident angle greater than or equal to a critical angle is totally reflected on the light incident surface 305b. As such, the light totally reflected on the light incident surface 305b of the diffusion member 305 is reflected when it proceeds to the reflective member 316, and the light incident on the light incident surface 305b of the diffusion member 305 at an incident angle below the critical angle is When the light is totally reflected and the light proceeds to the incident surface 305b of the diffusing member 305 at an angle of incidence less than or equal to the critical angle, the light is incident into the diffusing member 305 and then the outgoing surface 305a. It exits to the outside of the diffusion member 305 through).

Accordingly, the light emitted from the light emitting diode array 302 is totally reflected several times in the space formed by the diffusing member 305 and the reflecting member 316 so that the light is efficiently mixed.

That is, when the light emitting diodes 302a are individual light emitting diodes emitting red, green, and blue light, the light emitting diodes 302a are diffused after being converted into pure white light in the space formed by the diffusing member 305 and the reflecting member 316. It exits to the outside of the member 305. In addition, in the case where the light emitting diode 302a is a single element packaged with three light emitting diodes emitting red, green, and blue light, the light emitting diode 302a is further provided within the space formed by the diffusion member 305 and the reflective member 316. After being converted into uniform white light, it is emitted to the outside of the diffusion member 305. When the light emitting diode 302a is a light emitting diode 302a emitting white light, the light emitting diode 302a is converted into uniform white light having no bright spot in the space formed by the diffusion member 305 and the reflective member 316. Later, it is emitted to the outside of the diffusion member 305.

As described above, the liquid crystal display according to the third exemplary embodiment of the present invention has the effect of increasing the mixing ratio of the light emitted from the light emitting diode 302a by providing the diffusion member 305. In addition, the liquid crystal display device according to the third embodiment of the present invention includes a printed circuit board fixing means 304a so that the liquid crystal display device of the printed circuit board 303 assembled with the diffusion member 305 during the assembly process of the liquid crystal display device may be provided. Fastening can be easily performed without a separate guide means.

<Fourth Embodiment>

Finally, a liquid crystal display according to a fourth embodiment of the present invention will be described with reference to FIGS. 9 and 10.

9 is a cross-sectional view illustrating a liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 10 is an enlarged perspective view of a part of the liquid crystal display of FIG. 9, and shows only a part corresponding to a part of one LED array for convenience of description.

In describing the fourth embodiment of the present invention, the same descriptions as those of the first, second and third embodiments will be omitted.

As shown in FIG. 7, the liquid crystal display according to the fourth embodiment of the present invention comprises: a liquid crystal panel 401; At least one light emitting diode array 402 arranged in one direction below the liquid crystal panel 401 to supply light to the liquid crystal panel 401; At least one printed circuit board 403 on which the light emitting diode array 402 is mounted; A lower cover 404 in which the printed circuit board 403 is accommodated; It comprises a diffusion member 405 having a shape surrounding the upper and side portions of the light emitting diode array 402 and mixing the light emitted from the light emitting diode array 402. The diffusion member 405 extends from an upper surface of the printed circuit board 403 to provide a light incident surface 405b and a light emitting surface 405a, and the light emitting surface has a predetermined curvature.

In addition, the liquid crystal display according to the fourth embodiment of the present invention includes a printed circuit board fixing means 404a extending from the inside of the lower cover 404 and having a shape surrounding a part of the diffusion member 405. The reflective member 416 is provided on the printed circuit board 403. The optical sheet 407 is provided on the diffusion member 405.

As shown in FIGS. 9 and 10, the diffusion member 405 is provided in a shape surrounding the top and sides of the light emitting diode array 402 for each printed circuit board 403 on which the light emitting diode array 402 is mounted. The diffusion member 405 mixes the light emitted from the light emitting diode array 402.

The diffusion member 405 extends from an upper portion of the printed circuit board 403 to provide a light incident surface 405b and a light emitting surface 405a, and the light emitting surface 405a has a predetermined curvature.

In the accompanying drawings, the light emitting surface 405a of the diffusion member 405 has a predetermined curvature, but the light emitting surface 405b including the light emitting surface 405a is provided within the scope not departing from the gist of the present invention. In addition, various examples, such as having a predetermined curvature, are possible.

In the accompanying drawings, the coupling groove 405c provided in the diffusion member 405 is the same as the size of the light emitting diode 402a, so that the coupling groove 405c is integral with the light emitting diode 402a. The present invention is not limited thereto, and the fastening groove 405c may be larger than the light emitting diode 402a without departing from the gist of the present invention.

The diffusion member 405 is polymethylmethacrylate (PMMA), polyethylene terephtalate (PET), poly stylene (PS), acrylonitrile styrene copolymer (AS), meta stylene (MS), polymethylpentene (PMP), polycarbonate (PC), It is made of plastic material with higher refractive index than air, such as cyclic olefin copolymer (COC).

In the liquid crystal display device having the configuration as described above, a process of efficiently mixing the light emitted from the light emitting diodes 402a will be described.

The light emitted from the light emitting diode 402a is emitted from all the light emitting diodes 402a provided in the liquid crystal display until the light is emitted to the outside of the diffusion member 405 through the light emitting surface 405b of the diffusion member 405. The light is not mixed with the light, but is mixed with the light emitted from the light emitting diode 402a mounted on the printed circuit board 403 on which the light emitting diode 402a itself is mounted.

The light emitted from the light emitting diode 402a does not exist only in the light traveling in the vertical direction when the liquid crystal panel 401 is used as a reference, and light also travels in a predetermined slope. Further, the light emitted from the light emitting diode 402a travels with an angle smaller than the critical angle with respect to the light incident surface 405b of the diffusion member 405 and with an angle greater than the critical angle with respect to the light incident surface 405a. Angle exists.

Therefore, the light traveling from the light emitting diode array 402 to the light incident surface 405b of the diffusion member 405 at an angle less than or equal to the critical angle enters the diffusion member 405 and then exits the light emission surface 405a. Light emitted to the outside of the diffusion member 405 and traveling at an angle greater than or equal to a critical angle to the light incident surface 405b of the diffusion member 405 is totally reflected on the light incident surface 405b. As such, the light totally reflected on the light incident surface 405b of the diffusion member 405 is reflected when it proceeds to the reflective member 416 and is totally reflected when it proceeds at an angle below the critical angle of the light incident surface 405b of the diffusion member 405. When the light proceeds to the light incident surface 405b of the diffusion member 405 at an angle less than or equal to the critical angle after the process is repeated, the light incident surface 405a is incident after entering the inside of the diffusion member 405. It exits to the outside of the diffusion member 405 through.

Accordingly, the light emitted from the light emitting diode array 402 is totally reflected several times in the space formed by the diffusing member 405 and the reflecting member 416 so that the light is efficiently mixed.

That is, when the light emitting diodes 402a are individual light emitting diodes emitting red, green, and blue light, the light emitting diodes 402a are diffused after being converted into pure white light in the space formed by the diffusing member 405 and the reflecting member 416. It exits to the outside of the member 405. In addition, in the case where the light emitting diode 402a is a single device in which three light emitting diodes emitting red, green, and blue light are packaged, the light emitting diode 402a may be further formed in a space formed by the diffusion member 405 and the reflective member 416. After being converted into uniform white light, it is emitted to the outside of the diffusion member 405. When the light emitting diode 402a is a light emitting diode 402a emitting white light, the light emitting diode 402a is converted into uniform white light having no bright spot in the space formed by the diffusion member 405 and the reflective member 416. Later, it is emitted to the outside of the diffusion member 405.

As described above, the liquid crystal display according to the fourth exemplary embodiment of the present invention has the effect of increasing the mixing ratio of the light emitted from the light emitting diode 402a by providing the diffusion member 405. In addition, the liquid crystal display device according to the fourth embodiment of the present invention includes a printed circuit board fixing means 404a, so that the liquid crystal display device of the printed circuit board 403 assembled with the diffusion member 405 during the assembly process of the liquid crystal display device. Fastening can be easily performed without a separate guide means.

As described in detail above, the liquid crystal display according to the present invention produces uniform white light by increasing the mixing ratio of light emitted from the light emitting diode, thereby increasing the screen quality of the liquid crystal display.

In addition, the liquid crystal display device according to the present invention has an advantage of being easily performed by fastening the printed circuit board assembled with the diffusion member using the printed circuit board fixing means when the liquid crystal display device is assembled.

Claims (18)

A liquid crystal panel; At least one light emitting diode array arranged in one direction under the liquid crystal panel and having a plurality of light emitting diodes for supplying light to the liquid crystal panel; At least one printed circuit board on which the light emitting diode array is mounted; A lower cover accommodating the printed circuit board; A diffusion member disposed on an upper portion of the light emitting diode array and mixing light emitted from the light emitting diode array; First reflecting members disposed at sides of the light emitting diode arrays arranged in a row to reflect light emitted from the light emitting diode arrays toward the diffusion member; And a printed circuit board fixing means extending from the inside of the lower cover and having a shape surrounding a portion of the first reflecting member and the diffusion member. delete The liquid crystal display device according to claim 1, wherein the printed circuit board fixing means has elasticity. The liquid crystal display of claim 1, wherein the diffusion member is formed on the first reflection member. The liquid crystal display of claim 1, wherein the diffusion member extends from an upper surface of the printed circuit board to an upper end of the first reflective member. The liquid crystal display of claim 5, wherein a coupling groove is formed at a lower portion of the diffusion member to engage each of the plurality of light emitting diodes. The method of claim 1, wherein the diffusion member is polymethylmethacrylate (PMMA), polyethylene terephtalate (PET), poly stylene (PS), acrylonitrile styrene copolymer (AS), meta stylene (MS), polymethylpentene (PMP), polycarbonate (PC). ), A liquid crystal display, characterized in that made of any one of a cyclic olefin copolymer (COC). The method of claim 1, wherein the second reflective member is formed on the printed circuit board, And the second reflecting member reflects light emitted from the light emitting diode array to the diffusion member and the first reflecting member. A liquid crystal panel; At least one light emitting diode array arranged in one direction under the liquid crystal panel and having a plurality of light emitting diodes supplying light to the liquid crystal panel; At least one printed circuit board on which the light emitting diode array is mounted; A lower cover accommodating the printed circuit board; A diffusion member surrounding a top and a side of the light emitting diode array and mixing light emitted from the light emitting diode array; And a printed circuit board fixing means extending from the inside of the lower cover and having a shape surrounding a part of the diffusion member. delete 10. The liquid crystal display device according to claim 9, wherein the printed circuit board fixing means has elasticity. The method of claim 9, wherein the diffusion member is provided with a light incident surface and the light exit surface, And the light entering surface and the light emitting surface are curved surfaces having a predetermined curvature. 10. The liquid crystal display of claim 9, wherein the diffusion member has a predetermined curvature starting from one side of the printed circuit board and extending to the other side of the printed circuit board. The liquid crystal display of claim 9, wherein the diffusion member has a shape starting from one end of the upper surface of the printed circuit board and extending to the other end of the upper surface of the printed circuit board with a predetermined curvature. 15. The method of claim 14, wherein the diffusion member is extended from the upper surface of the printed circuit board is provided with a light incident surface and the light exit surface, The light emitting surface is a liquid crystal display, characterized in that the curved surface having a predetermined curvature. The liquid crystal display device of claim 15, wherein a coupling groove is formed at a lower portion of the diffusion member to engage each of the plurality of light emitting diodes. The method of claim 9, wherein the diffusion member is polymethylmethacrylate (PMMA), polyethylene terephtalate (PET), poly stylene (PS), acrylonitrile styrene copolymer (AS), meta stylene (MS), polymethylpentene (PMP), polycarbonate (PC). ), A liquid crystal display, characterized in that made of any one of a cyclic olefin copolymer (COC). 10. The liquid crystal display device according to claim 9, wherein a reflection member is provided on the printed circuit board to reflect light emitted from the light emitting diode array to the diffusion member.

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