KR101888424B1 - Liquid Crystal Display having fixing member for fixing Light Guide Panel - Google Patents

Abstract

A liquid crystal display according to an embodiment of the present invention includes a liquid crystal panel; A light guide plate disposed on a rear surface of the liquid crystal panel; A plurality of PCBs disposed on symmetrical opposite sides of the light guide plate and mounting a plurality of LEDs formed along the both side faces; An LED housing mounting the plurality of PCBs; A plurality of fixing members inserted into the plurality of holes formed in the LED housing and the plurality of PCBs to tighten the LED housing and the plurality of PCBs and protrude in a direction of facing the light guide plate; And a cover bottom having a plurality of protrusions protruding toward a side surface of the light guide plate and covering edges and bottom surfaces of the light guide plate and the LED housing, the plurality of fixing members and the plurality of protrusions surrounding the edge of the light guide plate And fixing the light guide plate.

Description

[0001] The present invention relates to a liquid crystal display (LCD) having a light guide plate fixing member,

Embodiments of the present invention relate to a liquid crystal display, and more particularly, to a liquid crystal display having a means for fixing a light guide plate.

2. Description of the Related Art Generally, a liquid crystal display (LCD) is a type of flat panel display that displays images using the electrical and optical characteristics of a liquid crystal having characteristics intermediate between a liquid and a solid. Thin and light, low power consumption and driving voltage are used in various applications throughout the industry.

On the other hand, the liquid crystal display device requires a separate light source because it is a non-luminescent element that emits light due to external factors.

Accordingly, a backlight unit having a light source on the back surface of the liquid crystal panel is provided to irradiate light toward the front surface of the liquid crystal display, and the light is diffused through a plurality of optical sheets (optical sheets) And is realized as an image that can be recognized only when it is condensed.

Generally, the backlight unit of the liquid crystal display device is divided into an edge-type and a direct-type according to the arrangement of a light-emitting lamp used as a light source.

In the direct type method, a plurality of lamps are arranged in a row on the back surface of a liquid crystal panel and directly irradiated onto the entire surface of the liquid crystal panel. In the edge type, a light source is provided outside the light guide plate for guiding light, And light is incident on the entire surface of the liquid crystal panel using the light guide plate.

Here, the edge method is mainly used because of its excellent durability and light weight and thinness of a liquid crystal display device.

1A is a sectional view of an edge type backlight unit.

The backlight unit 1 includes an LED assembly 25, a light guide plate 30, a reflective sheet 10, and an optical sheet 40.

The light emitted from the LED assembly 25 is incident on the light incidence surface 30a of the light guide plate 30. The light emitted from the LED assembly 25 is incident on the light incidence surface 30a of the light guide plate 30, .

The light guide plate 30 is formed by repeating total reflection, diffuse reflection, refraction and diffraction in the light incident from the LED assembly 25 installed on the light incidence surface 30a, which is one edge, And then emitted to the upper surface and the lower surface.

At this time, the reflective sheet 10 reflects the surface light source emitted to the lower surface so that the light guide plate 30 emits the surface light source only to the upper surface.

The surface light source is incident on the optical sheet 40 on the upper surface, and the optical sheet 40 partially condenses and diffuses (scatters) the incident surface light source and emits the light onto the upper surface.

Meanwhile, when the edge type backlight unit is used in a large-sized product such as a TV, fixing of the light guide plate is required to prevent the light guide plate from shaking. For this purpose, a fixing groove is formed in the light guide plate and a fixing pin is formed in the cover bottom.

1B is an exploded perspective view showing an assembly state of the light guide plate, the cover bottom, and the LED.

As shown in the figure, a fixing groove 33a is formed on a side surface of the edge portion of the light guide plate 30. The cover bottom 43 formed on the lower surface of the light guide plate 30 is formed with a fixing pin 33b protruding from the upper surface at a position corresponding to the fixing groove 33a.

The LED assembly 25 may be formed on opposite sides of the light guide plate 30.

In this case, the diameter of the hollow space inside the fixing groove 33a is equal to the diameter of the fixing pin 33b, and the fixing pin 33b is formed to surround the edge of the light guide plate 30 The light guide plate 30 can not move up and down and left and right.

Here, however, the close contact between the fixing groove 33a and the fixing pin 33b may cause cracks. This can be confirmed through the state in which the fixing groove 33a and the fixing pin 33b are fastened in the A region.

FIG. 1C is a partial perspective view of a state in which the fixing groove and the fixing pin are assembled in the area A of FIG. 1B.

Since the diameter of the fixing pin 33b is the same as the diameter of the fixing groove 33a, the tolerance between the fixing groove 33a and the fixing pin 33b is almost formed It does not. A configuration not described in the drawings is the LED assembly 25 and the cover bottom 43. [

When a certain impact is applied to the light guide plate 30, the fixation pin 33b and the fixing groove 33a of the light guide plate 30 are formed. In this case, The faces collide with each other. At this time, they all make line contact.

Line contact means an arbitrary line area which is in contact with each other and a large pressure acts on the impact surface of the fixing pin 33b and the fixing groove 33a of the light guide plate 30 do. The direction indicated by the arrow in the figure is the direction in which the pressure against the light guide plate 30 acts. In particular, since the B region is a corner portion, a larger pressure acts.

In addition, the fixing pin 33b is made of metal because it has durability against heat that may be generated in the light guide plate 30. In contrast, when the light guide plate 30 is made of a plastic material, cracks may easily occur on the light guide plate.

These cracks can cause more cracks over time. This has been pointed out as a very sensitive part of mechanical reliability.

Therefore, in order to solve the above problems, the embodiments of the present invention aim to prevent the occurrence of cracks in the light guide plate by forming a fixing member surrounding the light guide plate so as to make surface contact with the side face of the light guide plate.

According to an aspect of the present invention, there is provided a liquid crystal display device including: a liquid crystal panel; A light guide plate disposed on a rear surface of the liquid crystal panel; A plurality of PCBs disposed on symmetrical opposite sides of the light guide plate and mounting a plurality of LEDs formed along the both side faces; An LED housing mounting the plurality of PCBs; A plurality of fixing members inserted into the plurality of holes formed in the LED housing and the plurality of PCBs to tighten the LED housing and the plurality of PCBs and protrude in a direction of facing the light guide plate; And a cover bottom having a plurality of protrusions protruding toward a side surface of the light guide plate and covering edges and bottom surfaces of the light guide plate and the LED housing, the plurality of fixing members and the plurality of protrusions surrounding the edge of the light guide plate And the light guide plate is fixed.

Preferably, the opposite surfaces of the plurality of fixing members and the plurality of protrusions facing the side surface of the light guide plate and the side surface of the light guide plate are flat.

Further, the distance between the plurality of fixing members and the light guide plate is closer to the distance between the LED and the light guide plate.

The direction in which the plurality of fixing members are inserted is perpendicular to the side surface of the light guide plate.

Further, the plurality of fixing members are disposed at symmetrical positions with the light guide plate as a center.

The fixing member may include: a first fixing part having a larger diameter than the hole formed in the LED housing and projecting toward the light guide plate; A third fixing part having a larger diameter than the hole formed in the LED housing and disposed on the surface facing the first fixing part with the hole therebetween; And a second fixing part penetrating into the hole formed in the LED housing and connecting the first fixing part and the third fixing part.

Further, the plurality of fixing members are formed of a metal.

According to another aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, comprising: forming a plurality of holes on a same line of a light emitting surface of a light guide plate; A plurality of fixing members, such as a diameter of the plurality of holes, for connecting the first and third fixing portions, which are larger than the diameter of the plurality of holes, are inserted into the plurality of holes, 1) inserting the fixing part so as to protrude from one surface of the LED housing; A second fixing portion of the plurality of fixing members is inserted into the hole to fasten the LED housing and the plurality of fixing members; Mounting an LED assembly having a plurality of holes in the LED housing so as to pass through the plurality of fixing members; Placing the LED housing on a cover bottom so that a plurality of protrusions formed on the inner surface of the cover bottom are collinear with the plurality of fixing members; Placing the light guide plate on the LED housing and surrounding and fixing the edges with the plurality of fixing members and the plurality of protrusions; And disposing a liquid crystal panel on a front surface of the light guide plate and engaging a top cover and a cover bottom on an upper surface of the liquid crystal panel.

Preferably, the plurality of fixing members and the plurality of projections further include flat surfaces of the light guide plate and the opposed surfaces of the plurality of fixing members and the plurality of projections facing the side surfaces of the light guide plate.

In addition, the distance between the plurality of fixing members and the light guide plate is arranged to be closer to the distance between the LED assembly and the light guide plate.

The direction in which the plurality of fixing members are inserted into the plurality of holes is perpendicular to the side surface of the light guide plate.

The plurality of LED assemblies and the plurality of fixing members may be disposed symmetrically with respect to the light guide plate.

The liquid crystal display device according to at least one embodiment of the present invention configured as described above,

The fixing pin protruding from the cover bottom to the upper surface can be formed as a fixing member protruding toward the side surface of the light guide plate to eliminate the fixing groove of the light guide plate, thereby eliminating the fixing groove forming process in the light guide plate process.

The fixing member is formed to be in surface contact with the side surface of the light guide plate in the event of a collision, thereby reducing the amount of impact.

The impact amount reduction can prevent the light guide plate and the fixing member from cracking and improve the durability of the light guide plate.

1A is a sectional view of an edge type backlight unit.
1B is an exploded perspective view showing an assembly state of the light guide plate, the cover bottom, and the LED.
FIG. 1C is a partial perspective view of a state in which the fixing groove and the fixing pin are assembled in the area A of FIG. 1B.
2 is an exploded perspective view of a liquid crystal display device according to an embodiment of the present invention.
3 is a plan view of a portion of the backlight unit.
4A is a sectional view of the first fixing member.
4B shows a partial perspective view of the first fixing member inserted into the LED housing.
5A is a sectional view of the second fixing member.
5B is a partial perspective view of the second fixing member inserted into the LED housing.
6A is a sectional view of the third fixing member.
6B shows a partial perspective view of the third fixing member inserted into the LED housing.
7A is a sectional view of the fourth fixing member.
7B shows a partial perspective view of the fourth fixing member inserted into the LED housing.
FIGS. 8A and 8B are graphs showing stress and displacement measured according to one embodiment of the present invention and the prior art. FIG.

Hereinafter, a liquid crystal display device according to an embodiment of the present invention will be described in detail with reference to the drawings.

In the present specification, the same or similar reference numerals are given to different embodiments in the same or similar configurations.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

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

2, the liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel 200 on which an image is displayed, a liquid crystal panel 200 connected to one side of the liquid crystal panel 200 to drive the liquid crystal panel 200 A circuit unit 300 and a backlight unit 100 disposed on the back surface of the liquid crystal panel 200 and irradiating the liquid crystal panel 200 with light.

The edge of the liquid crystal panel 200 is supported by the mold frame 420. The mold frame 420 and the backlight unit 100 are combined with a top cover 410 covering the entire surface of the liquid crystal panel 200.

The liquid crystal panel 200 includes a thin film transistor substrate 220, a color filter substrate 210 opposed to the thin film transistor substrate 220, and a liquid crystal layer 210 interposed between the thin film transistor substrate 220 and the color filter substrate 210 (Not shown). The liquid crystal panel 200 displays an image by adjusting the light transmittance of the liquid crystal cells according to the image signal information transmitted from the driving circuit unit 300.

A driving circuit unit 300 for applying a driving signal to the liquid crystal panel 200 is provided on one side of the thin film transistor substrate 220. The driving circuit unit 300 includes a flexible printed circuit board 310, a driving chip 330 mounted on the flexible printed circuit board 310 and a circuit board 320 connected to the other side of the flexible printed circuit board 310 .

A backlight unit 100 is disposed on the back surface of the liquid crystal panel 200. The backlight unit 100 includes an optical sheet 140 formed on the back surface of the liquid crystal panel 200 and diffusing and condensing light, a light guide plate 130 disposed on the back surface of the optical sheet 140, A reflective sheet 110 provided on the back surface of the light guide plate 130 and a cover bottom 430 for receiving and fixing the light guide plate 130. The LED assembly 125 is provided along at least one side and emits light.

The optical sheet 140 disposed parallel to the back surface of the liquid crystal panel 200 includes a diffusion sheet 141, a prism sheet 145, and a protective sheet 149 which are sequentially stacked. The diffusion sheet 141 includes a base film (not shown) and a diffusion coating layer (not shown) formed on the entire surface of the base film. The diffusion sheet 141 diffuses light from the LED assembly 125 and supplies the light to the liquid crystal panel 200 It plays a role.

A prism sheet 145 and a protective sheet 149 are provided on the diffusion sheet 141. The prism sheet 145 has a triangular columnar prism with a predetermined arrangement on its upper surface, and allows light passing through the diffusion sheet 141 to proceed vertically, thereby improving brightness. On the prism sheet 145, a protective sheet 149 for preventing external impact or foreign matter from entering is provided to protect the diffusion sheet 141 and the prism sheet 145 sensitive to dust or scratches.

The light guide plate 130 is provided in a rectangular shape having a predetermined thickness. The light guide plate 130 is provided to oppose the LEDs 125b disposed on both sides of the LED 125b and emits light incident on both sides of the light entrance surface 130a on which the light emitted from the LED 125b is incident and the light entrance surface 130a Emitting surface 130b and a reflecting surface (not shown) facing the emitting surface 130b downward. The light incidence surface 130a may be formed in one or more of the side surfaces of the light guide plate 130. [

Here, the side surfaces of the light guide plate 130 including the light incidence surface 130a are both flat and smooth.

The material of the light guide plate 130 may be any one of PMMA (polymethyl methacrylate), PET (polyethylene terephthlate), PC (poly carbonate), and PEN (polyethylene naphthalate). And may have a characteristic of shrinking or expanding by a predetermined range depending on the temperature in the nature of the material.

The LED assembly 125 is disposed along the light incidence surface 130a provided on both opposite sides of the light guide plate 130. [ The LED assembly 125 includes a PCB 125a (Printed Board Circuit) that applies an electrical signal to the LED 125b and the LED 125b.

Here, the LED assembly 125 is formed corresponding to the light incidence surface 130a of the light guide plate 130. Accordingly, a plurality of LED assemblies 125 may be formed on the side of the light guide plate 130 according to the number of the light incidence surfaces 130a.

The plurality of LEDs 125b are disposed on the PCB 125a at regular intervals.

In addition, the LED 125b may emit only one of blue, red, and green wavelengths, or may be a white light supply unit that combines the LEDs 125b including both of these wavelengths.

Here, not only the LED 125b but also a cold cathode fluorescent lamp (CCFL), an external electro fluorescent lamp (EEFL), or the like may be used as the light source.

At this time, since the LED 125b generates much heat, the PCB 125a located on the back surface of the LED 125b may be made of aluminum (Al) having a good heat transfer rate as a main material.

The LED assembly 125 is mounted on the LED housing 120. The LED housing 120 protects the LED assembly 125 and concentrates the light emitted from the LED 125b in the direction of the light guide plate 130, And the heat dissipation effect of the LED assembly 125 is improved. The LED housing 120 may be referred to as a light source LED housing 120.

At this time, the LED housing 120 may be formed in an 'a' shape. In the 'b' shape, the vertical portion mounts the LED assembly 125, and the horizontal portion supports the light guide plate 130 and diffuses the heat generated by the LED assembly 125.

A plurality of fixing members M having a predetermined width and length are inserted into the vertical portion in a direction in which the LED 125b faces the light incidence surface 130a of the light guide plate 130. [ At this time, the LED housing 120 and the PCB 125a are formed with a plurality of holes into which the plurality of fixing members M are inserted.

Here, the fixing member M, the LED housing 120, and the PCB 125a are assembled in the following order.

First, a hole is formed in a vertical portion of the LED housing 120, and the fixing member M is inserted into the hole. A hole through which the fixing member M can be inserted is formed on the PCB 125a and the PCB 125a is closely disposed on one side of the vertical part of the LED housing 120. [

The fixing member M may be inserted into the LED housing 120 in the form of a screw or the like and the LED housing 120 and the PCB 125a may be bonded to each other with an adhesive material. Alternatively, the fixing member M may function to adhesively fix the LED housing 120 and the PCB 125a.

For example, when a member having a diameter larger than the diameter of the hole formed in the LED housing 120 and the PCB 125a is formed on the outer surface of the LED housing 120 and the hole of the PCB 125a, Can be achieved. Or a spiral groove may be formed in the inner hole of the LED housing 120 and the PCB 125a and a spiral groove may be formed in the fixing member M so that the fixing member M is inserted.

At this time, the direction of the fixing member M toward the light incidence surface 130a and the light incidence surface 130a may be perpendicular to each other.

Also, the fixing member M is formed symmetrically on the LED housing 120 on the opposite side.

The distance between the facing surface of the fixing member M facing the light incidence surface 130a and the light incidence surface 130a of the light guiding plate 130 is narrowed to a predetermined range.

Accordingly, the light guide plate 130 can not be moved beyond the range of the gap, and thus the light guide plate 130 is fixed by the fixing member M.

The reflective sheet 110 on the lower surface of the light guide plate 130 reflects light leaking in a direction opposite to the liquid crystal panel 200 from the light emitted from the LED assembly 125 to the light guide plate 130 to reduce the loss of light. do. The reflective sheet 110 may be made of PET (polyethylene terephthalate), PC (poly carbonate), or the like.

The cover bottom 430 may be made of a synthetic resin having an insulating property as described above. The cover bottom 430 may be formed of a resin, Lt; RTI ID = 0.0 > 420 < / RTI >

The cover bottom 430 has a protrusion L protruding toward the side surface of the light guide plate 130 on the inner surface of the cover bottom 430 for fixing the light guide plate 130.

The protrusion L is formed on the same horizontal line as the fixing member on the side of the light guide plate 130 that is different from the side on which the fixing member M is formed.

The protrusion L fixes the light guide plate 130 against the movement of the light guide plate 130 in the other direction in which the fixing member M is not fixed.

Now, the shape in which the light guide plate 130, the fixing member M, and the protrusion L of the cover bottom 430 are assembled will now be described in more detail.

3 is a plan view of a portion of the backlight unit.

The LED assembly 120, the LED assembly 125, the fixing member M, the light guide plate 130, and the cover bottom 430 are assembled.

The fixing member M is inserted into a hole (not shown) formed in the LED housing 120 and the PCB 125a and is disposed on opposite sides of the light guide plate 130 in the x direction. On one side of the LED housing 120, two fixing members M are spaced apart from each other at a predetermined interval. The distance d1 between the facing surface M100 of the fixing member M and the light incident surface 130a of the light guide plate 130 may be the same.

As a result, the light guide plate 130 is fixed in the x direction within the allowable range of d1.

The fixing member M is further protruded toward the light guide plate 130 than the LED assembly 125. This is to prevent contact with the LED 125b because the LED 125b may be broken when the LED 125b and the light guide plate 130 are in contact with each other.

Further, the material of the fixing member M may be a metal. For example, stainless steel, among which SUS304 or SUS316 may be used.

The protrusion L of the cover bottom 430 is formed on opposite sides of the cover bottom 430 facing the y-direction of the light guide plate 130. The distance d2 between the facing surface L100 of the protrusion L and the light incident surface 130a of the light guide plate 130 may be the same.

Therefore, the light guide plate 130 is fixed in the y direction within the allowable range of d2.

The protrusion L may be integrally formed with the cover bottom 430 by compression molding the inner surface of the cover bottom 430.

Instead of the projecting portion L of the cover bottom 430, a hole may be formed in the cover bottom 430 and a fixing member M may be inserted. That is, since the fixing member M is also used for fixing the light guide plate 130, the fixing member M may be replaced by the fixing member M instead of the projection L.

At this time, d1 and d2 are set at the same interval in the drawing, but they may be different from each other.

The opposite surfaces M100 and L100 of the protrusion L and the fixing member M may be formed to be flat against the light incidence surface 130a of the light guide plate 130. [

This means that the portion of the light guide plate 130 that contacts the fixing member M and the projection L in a collision becomes a face. That is, conventionally, a large pressure is generated in the contact region with respect to a force generated when the light guide plate 130 and the fixing member M come into contact with each other in the area of a line or a dot, Thereby reducing the impact force by using the contact area as a face. As a result, this reduces the impact force applied to the light guide plate 130 and the fixing member M, thereby preventing the occurrence of cracks in the light guide plate 130 and the fixing member M. [

Further, since the light guide plate 130 is fixed in the x and y directions, it is not necessary to form the fixing groove in the light guide plate 130 and to insert the fixing pin as in the prior art. This leads to a result that the fixing groove forming process can be removed separately in the process of the light guide plate 130, thereby reducing the processing cost.

The position, number and shape of the protrusion L and the fixing member M are not limited to the embodiment of the present invention.

The number of the LED housings 120 varies depending on the number of the light incidence surfaces 130a of the light guide plate 130, as shown in FIG. Accordingly, one or more LED housings 120 may be formed on the side surface of the light guide plate 130.

The protrusion L of the cover bottom 430 may be formed on the entire side surface where the LED housing 120 is not formed to surround the edge of the light guide plate 130 together with the fixing member M of the LED housing 120 have.

At this time, the plurality of fixing members M and the protrusions L may be disposed at symmetrical positions with the light guide plate 130 at the center.

Unlike the drawings, the number of the fixing members M and the protrusions L formed on one side may be one or three or more.

The protrusion L may be formed on the inner surface of the top cover 410. At this time, the top cover 410 may surround the edge of the light guide plate 130.

Here, the fixing member M may be formed in a structure that is inserted into and separated from the hole formed in the LED housing 120.

Next, a detailed configuration of the LED housing and the fixing member that can be inserted and removed will be described.

Here, the configuration of the fixing member M includes a first fixing portion, a second fixing portion, and a third fixing portion.

In the following, the LED housing and the PCB of Figs. 4B, 5B, 6B, and 7B show only a part of the LED in a rectangular parallelepiped shape.

4A is a sectional view of the first fixing member.

The first fixing member M1 is cylindrical and has different diameters for the fixing portions F1, F2 and F3.

The insertion direction of the first fixing member M1 is a direction from the outer surface 120b of the LED housing 120 to the light guide plate 130. [ After the insertion of the first fixing member M1, the second fixing portion F2 of the first fixing member M1 is completely inserted into the LED housing 130 at the moment of insertion.

The construction of the first fixing member M1 will be described below.

The first fixing part F1 of the first fixing member M1 is inserted into the PCB 125a of the LED housing 120 and protrudes toward the light guide plate 130. [ And is connected to the second and third fixing portions F2 and F3.

The second fixing portion F2 is smaller than the diameters R1 and R3 of the first and third fixing portions F1 and F3 and serves as an intermediate of the first and third fixing portions F1 and F3. The second and third fixing portions F2 and F3 are inserted into the LED housing 120. [ At this time, the LEDs are inserted into the holes formed in the LED housing 120, and the holes have a shape in which a step is formed in the LED housing 120 because the diameters R2 and R3 of the second and third fixing portions F2 and F3 are different I have.

The LED housing 120 is penetrated into the first fixing member M1 in the region of the second fixing portion F2 so that when the LED housing 120 receives an impact from the light guide plate 130, 1 and the third fixing parts F1 and F3 and may not be emitted to the inside or the outside of the LED housing 120. [

The third fixing portion F3 is formed between the outer surface 120b of the LED housing 120 and the inner surface of the cover bottom 430 by being inserted into the LED housing 120 You can narrow the tolerance.

After the first fixing member M1 is inserted into the LED housing 120, the PCB 125a is fastened to the first fixing member M1.

4B is a partial perspective view of the first fixing member inserted into the PCB and the LED housing.

The first and second fixing portions F1 and F2 of the first fixing member M1 are not visible because the second and third fixing portions F2 and F3 are inserted into the LED housing 120, As shown in Fig.

5A is a sectional view of the second fixing member.

The second fixing member M2 is also cylindrical and has different diameters for the fixing portions F1, F2 and F3.

The insertion direction of the second fixing member M1 is a direction from the light guide plate 130 to the LED housing 120. The second fixing member M1 is completely fastened when the second fixing portion F2 of the second fixing member M1 is inserted into the LED housing 130 after the insertion.

The configuration of the second fixing member M2 will be described below.

The first fixing part F1 of the second fixing member M2 is inserted into the PCB 125a and protruded toward the light guide plate 130. [ This is connected to the second and third fixing portions F2 and F3 and the second and third fixing portions F2 and F3 are the same as those of the first fixing member M1.

The second fixing member M2 is different from the first fixing member in that the first fixing portion F1,

to be.

The lower diameter R4 of the first fixing portion F1 is formed to be larger than the diameter R3 of the third fixing portion F3. That is, the LED housing 120 penetrating between the first fixing portion F1 and the third fixing portion F3 becomes thicker. As a result, the fixing force against the external impact becomes stronger than in the case of the first fixing member M1.

5B is a partial perspective view of the second fixing member inserted into the LED housing.

As shown in the drawing, the first fixing portion F1 of the second fixing member M2 has a large diameter portion inserted into the PCB 125a and the remaining portion protruding from the PCB 125a. The second and third fixing portions F2 and F3 are inserted into the LED housing 120 and are not seen.

6A is a sectional view of the third fixing member.

The third fixing member M3 is a screw. A spiral groove 243 is formed in the second fixing portion F2 of the structure of the third fixing member M3 and a spiral groove is formed in the LED housing 120 corresponding thereto. Therefore, the third fixing member M3 is fixed by the second fixing portion F2.

The first fixing portion F1 has a flat surface facing the side surface of the light guide plate 130. [ And a lower portion of the first fixing portion F1 is inserted into the PCB 125a.

The third fixing portion F3 protrudes from the outer surface 120b of the LED housing 120 and may be inserted into the LED housing 120 in some cases.

6B shows a partial perspective view of the third fixing member M3 inserted into the LED housing 120. As shown in FIG.

As shown in the drawing, a part of the first fixing part F1 of the third fixing member M3 is inserted into the PCB 125a, and the remaining part of the fixing part F1 protrudes from the PCB 125a. The second fixing portion F2 is inserted into the LED housing 120 and the third fixing portion F3 is formed on the outer surface of the LED housing 120 to be invisible.

7A is a sectional view of the fourth fixing member.

The fourth fixing member M4 is joined by two components unlike the first to third fixing members. The first fixing portion F1 and the second fixing portion F2 are formed integrally with each other and the third fixing portion F3 is formed separately from the end of the second fixing portion F2.

When the first fixing part F1 and the second fixing part F2 are inserted in the light guide plate 130 in the direction of the outer surface 120b of the LED housing 120, Is fixed along the spiral groove formed in the second fixing portion (F2) in the direction of the light guide plate (130) from the outer side surface (102b) of the light guide plate (120).

At this time, the third fixing portion F3 may be formed in the LED housing 120 by forming a groove in the LED housing 120.

Thereafter, the PCB 125a is fastened to the fourth fixing member M4.

7B shows a partial perspective view of the fourth fixing member inserted into the LED housing.

As shown in the drawing, a part of the first fixing part F1 of the fourth fixing member M4 is inserted into the PCB 125a, and the remaining part has a shape protruding from the PCB 125a. The second fixing portion F2 is inserted into the LED housing 120 and the third fixing portion F3 is disposed on the outer surface of the LED housing 120 and is not visible.

In addition to the above-described configuration, the fixing member M may be any one of a set of bolts and nuts, or a flat surface that is inserted into the LED housing or cover bottom such as a rivet and faces the light guide plate.

FIGS. 8A and 8B show graphs obtained by measuring stress and displacement of an embodiment of the present invention and a conventional art when there is an impact. FIG.

In each graph, the value of the vertical axis in the embodiment of the present invention is a percentage value based on a case where the measurement result value of the prior art is regarded as 100%.

8A compares the liquid crystal display according to the prior art and one embodiment of the present invention with respect to stress.

The stresses applied to the fixing member and the prior art fixing pins are compared by equivalent stress. Equivalent Stress refers to the equivalent sum of the various stresses applied to an object.

And the stress applied to the light guide plate is compared with the principal stress. Principal stress means the vertical stress when only the normal stress acts on a certain surface including an arbitrary point in the object receiving the external force without shear stress acting. do.

Referring to the drawings, when the first fixing member and the second fixing member are used in the embodiment of the present invention, the principal stress of the light guide plate and the equivalent stress of the fixing member are smaller than those of the prior art.

This means that, when the same impact force is applied, the impact amount of the embodiment of the present invention on the light guide plate and the fixing member is smaller than in the prior art.

Fig. 8B shows a comparison between a liquid crystal display according to the prior art and an embodiment of the present invention in terms of displacement. The displacement refers to the displacement of the light guide plate and the fixed member after the impact.

In the drawings, displacement of the fixing member is reduced by about 40% when compared with the prior art, in which the second fixing member and the first fixing member are used. And about 30% at the displacement plane of the light guide plate.

As a result, it can be seen that when the same impact force is applied, the displacement of the light guide plate and the fixing member of the embodiment of the present invention is further reduced as compared with the prior art.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Therefore, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also within the scope of the present invention.

100: backlight unit 120: LED housing
125: LED assembly 125a: PCB
125b: LED 130: light guide plate
430: cover bottom M: fixing member
L: protrusion

Claims (7)

A liquid crystal panel;
A light guide plate disposed on a rear surface of the liquid crystal panel;
A plurality of PCBs disposed on symmetrical opposite sides of the light guide plate and mounting a plurality of LEDs formed along the both side faces;
An LED housing mounting the plurality of PCBs;
A plurality of fixing members inserted into the plurality of holes formed in the LED housing and the plurality of PCBs to tighten the LED housing and the plurality of PCBs and protrude in a direction of facing the light guide plate; And
And a cover bottom having a plurality of protrusions protruding toward a side surface of the light guide plate and covering edges and bottom surfaces of the light guide plate and the LED housing,
The plurality of fixing members and the plurality of protrusions surround the edge of the light guide plate, fix the light guide plate,
Wherein:
A first fixing part having a larger diameter than the hole formed in the LED housing and protruding toward the light guide plate,
A third fixing part having a larger diameter than the hole formed in the LED housing and arranged to face the first fixing part with the hole therebetween and inserted into the outer side surface of the LED housing,
And a second fixing part penetrating into the hole formed in the LED housing and connecting the first fixing part and the third fixing part. The method according to claim 1,
And the opposing surfaces of the plurality of fixing members and the plurality of protrusions facing the side surface of the light guide plate and the side surface of the light guide plate are flat. The method according to claim 1,
Wherein a distance between the plurality of fixing members and the light guide plate is shorter than a distance between the LED and the light guide plate. The method according to claim 1,
And the direction in which the plurality of fixing members are inserted is perpendicular to the side surface of the light guide plate. The method according to claim 1,
Wherein the plurality of fixing members are disposed symmetrically with respect to the light guide plate. delete The method according to claim 1,
Wherein the plurality of fixing members are made of metal.

Images