KR100670824B1 - Backlight assembly for LCD - Google Patents

Abstract

This is to prevent the light from being concentrated due to the concentration of light at the corner formed at right angles from the incident surface of the light guide plate facing the lamp assembly. The light is wrapped around the edge of the incident surface or the edge of the light guide plate incident surface is rounded to enter the corner. Block the light or reduce the amount of light.

This prevents bright bright lines from being generated adjacent to the lamp assembly, thereby improving the uniformity of light.

Light guide plate, Reflective projection, Lamp cover, Light blocking step, Light blocking cushion, Corner round

Description

Backlight assembly for liquid crystal display {Backlight assembly for LCD}

1 is a perspective view showing a state in which a lamp assembly and a light guide plate are combined in a conventional liquid crystal display.

FIG. 2 is a cross-sectional view taken along the line II of FIG. 1. FIG.

3 is an exploded perspective view schematically showing the structure of a backlight assembly according to a first embodiment of the present invention;

Figure 4 is a perspective view showing a state in which the lamp assembly and the light guide plate according to the first embodiment of the present invention is coupled.

Figure 5 is a perspective view showing a state in which the lamp assembly and the light guide plate according to the second embodiment of the present invention,

6 is a perspective view showing a state in which the lamp assembly and the light guide plate according to the third embodiment of the present invention are coupled.

The present invention relates to a backlight assembly of a liquid crystal display, and more particularly, to process a corner formed at a right angle at the incidence plane of the light guide plate facing the lamp or to block light from being incident on an edge, so that the bright line is extended toward the longitudinal direction of the lamp. The present invention relates to a backlight assembly of a liquid crystal display device which is prevented from being generated.

CRT (Cathode Ray Tube), one of the commonly used display devices, is mainly used for monitors such as TVs, measuring devices, information terminal devices, etc., but due to the weight and size of the CRT itself, Could not respond actively to the demand.

In order to replace the CRT, the development of a liquid crystal display device having advantages such as miniaturization, light weight, and low power consumption has been actively progressed, and recently, the liquid crystal display device has been developed to be sufficient to serve as a flat panel display device. Demand is constantly increasing.

Since the liquid crystal display device displays information by using the electro-optical properties of the liquid crystal injected into the LCD panel, in the case of the light-receiving liquid crystal display device, a separate dimming device for emitting and guiding light to the back of the LCD panel, namely The backlight assembly is essential.

The backlight assembly may be installed in a storage space of a frame to reflect light, a light guide plate installed on an upper surface of the reflective sheet to guide incident light toward the LCD panel, and a light guide plate installed on an upper surface of the light guide plate and transmitted from the light guide plate. It includes an optical sheet for increasing the brightness of the light, a lamp assembly installed on the width side of the light guide plate to emit light, and a top chassis that is covered on the upper portion of the LCD panel and fastened to the frame.

In recent years, as the size of the liquid crystal display device increases, high luminance and high resolution are required, so that the light incident on the light guide plate is emitted toward the optical sheet by printing a diffused dot on the lower surface of the light guide plate facing the reflective sheet. As shown in FIG. 2, a method of outputting light incident on the light guide plate 20 toward the optical sheet by forming a reflective protrusion 24 having a predetermined slope by processing the lower surface of the light guide plate 20 is used.

That is, when the diffuse reflection dot is printed on the lower surface of the light guide plate, the light emitted from the lamp is incident into the inside of the light guide plate and proceeds to total reflection, and is then emitted through the upper surface of the light guide plate. Some of the light is absorbed by the diffuse reflection dot and the remaining light is reflected from the diffuse reflection dot and then diffused in various directions to be emitted to the outside of the light guide plate.

On the other hand, as shown in FIGS. 1 and 2, when the reflecting protrusion 24 having a predetermined inclination is formed on the lower surface of the light guide plate 20, light emitted from the lamp 42 is emitted from the light guide plate 20. When the light is incident to the inside of the light guide plate 20 when it is reflected inside the light guide plate 20 when it is reflected in the upper surface of the light guide plate 20 without being absorbed or diffused, the light exits to the top surface of the light guide plate 20. Use efficiency is increased.

However, when the incident light is emitted to the outside of the light guide plate 20 by forming the reflection protrusions 24 on the lower surface of the light guide plate 20, the incident surface of the light guide plate 20 facing the lamp 42 is provided. The light is concentrated (see FIG. 2) at the corner a formed at right angles of the light beams 22, and is incident into the light guide plate 20, and the light incident at the corners a does not diffuse after hitting the reflection protrusion 24. Since it is emitted as it is, as shown in FIG. 1, bright band-shaped bright lines are generated in the portion (b) close to the lamp assembly 40.

Since the bright line is closer to the lamp assembly 40, the brighter line becomes brighter and is easily recognized by the human eye, thereby reducing the light uniformity of the liquid crystal display.

Here, even when using a light guide plate on which diffuse reflection dots are formed, a bright line appears, but the user is hardly aware because light concentrated at the corners diffuses when emitted by the diffuse reflection dots after being incident on the light guide plate.

On the other hand, in order to prevent light leakage or light ridges from occurring, almost no frame is provided with a separate fixing means for fixing the light guide plate. Due to the manufacturing tolerances of the light guide plate flows due to this collides with the light guide plate and the lamp there is a problem that the lamp is damaged, thereby reducing the reliability of the liquid crystal display device.

Here, reference numeral 50 denotes a lamp cover surrounding the lamp 42.

Accordingly, an object of the present invention is to conceive in view of the above problems, by processing the corner of the light guide plate facing the lamp in a predetermined shape to prevent the concentration of light or to enter the light at the edge of the incident surface It is to prevent the occurrence of bright lines in a predetermined portion of the LCD panel by blocking the.

Another object of the present invention is to prevent the light guide plate from being damaged by being pushed toward the lamp by impact or vibration.                         

Further objects of the present invention will become apparent from the following detailed description and the accompanying drawings.

In order to achieve the above object, the present invention is inserted into the storage space of the frame and reflects the light, and is installed on the upper surface of the reflective sheet, the lower surface facing the reflective sheet and the light incident inside Lamp having a light guide plate formed with reflective projections for exiting the LCD panel, a lamp installed on the side of the light guide plate and a lamp cover which is opened on one side facing the light guide plate while covering the lamp and is fitted to the light guide plate It is composed of an optical sheet installed on the assembly and the upper portion of the light guide plate to increase the brightness of the light emitted from the light guide plate, in order to prevent the light is concentrated in the corner of the incident surface of the light guide plate facing the lamp assembly to prevent the light from entering the inside of the light guide plate. The edges are processed into round shapes or the edges are formed with light blocking portions.

For example, the light blocking portion is formed at a boundary between a portion of the lamp cover into which the lamp is inserted and a portion into which the light guide plate is inserted.

Preferably, the light blocking portion is generated on the upper and lower surfaces of the lamp cover by forming the height of the portion where the lamp is inserted to be lower than the height of the portion where the light guide plate is inserted.

In addition, the light shielding portion is formed by protruding the upper and lower surfaces of the lamp cover by a predetermined length toward the boundary between the portion where the lamp is inserted and the portion where the light guide plate is inserted .

As another example, the light blocking portion is a cushion having an elastic force, which is provided between the lamp cover and the light guide plate so as to protrude from the light guide plate by a predetermined length toward the lamp.

Hereinafter, a structure of a backlight assembly of a liquid crystal display according to the present invention will be described with reference to FIGS. 3 to 6.

The backlight assembly 100 according to the present invention is accommodated in the storage space of the frame (not shown) reflecting light 110, the light guide plate 120 is installed on the upper surface of the reflective sheet 110 to guide the light In addition, the lamp assembly 140 is installed on one side or both sides of the light guide plate 120 in the width direction to emit light, and the optical sheets 160 installed on the top surface of the light guide plate 120 to increase the brightness of the light and electrical and optical It includes a top chassis (not shown) that is covered on the top of the LCD panel 180 for displaying information by the characteristics and is fastened to the frame.

Preferably, the optical sheets 160 are composed of a prism sheet for collecting light and a protective sheet for protecting the prism sheet.

According to the first embodiment, as shown in FIGS. 3 and 4, the edges of the incident surface 122 of the light guide plate 120 facing the lamp assembly 140 are formed at right angles, and face the reflective sheet 110. A plurality of triangular reflective protrusions 124 having a predetermined height is formed on the lower surface of the light guide plate 120, and the reflective protrusions 124 extend long along the longitudinal direction of the lamp assembly 140.

In addition, the lamp assembly 140 may include a lamp 142 that emits light as illustrated in FIGS. 3 and 4, and an outer circumferential surface of the lamp 142 to reflect the light emitted from the lamp 142 toward the light guide plate 120. It is composed of an inverter (not shown) electrically connected to the lamp 142 by a lamp cover 150 and a wire surrounding the lamp to supply power to the lamp 142.

Here, one widthwise side surface of the lamp cover 150 facing the incident surface 122 of the light guide plate 120 is opened and fitted to the incident surface 122 of the light guide plate 120. The height of the portion 152 (hereinafter referred to as "lamp insertion portion") is inserted is formed lower than the thickness of the light guide plate 120 and the portion where the light guide plate 150 is inserted (156 (hereinafter referred to as "light guide plate insertion portion")) The light guide plate 150 is formed to be slightly higher than the thickness of the light guide plate 150 to generate a light blocking step 154 on each of the upper and lower surfaces of the lamp cover 150.

The light blocking step 154 is formed at the boundary between the lamp insertion portion 152 and the light guide plate insertion portion 156 to prevent light from being incident on the edges formed at the top and bottom of the incident surface 122.

As described above, although the height of the lamp insertion portion 152 and the light guide plate insertion portion 156 may be different from each other in the lamp cover 150 to form the light blocking step 154, the lamp insertion as shown in FIG. A light blocking step 154 may be formed by forming a protrusion 153 having a predetermined length toward the lamp 142 at the boundary between the portion 152 and the light guide plate inserting portion 156.

3 and 4, when the lamp cover 150 having the light blocking step 154 formed on the incident surface 122 of the light guide plate 120 is inserted, the light blocking step 154 and the light guide plate inserting portion 156 are inserted. ) Wraps around the edges formed at the top and bottom of the incident surface 122.

When the edge of the incident surface 122 is surrounded by the light blocking step 154 and the insertion portion 156 of the light guide plate, since the light emitted from the lamp 142 is completely reflected by the light blocking step 154. Light does not enter the edge of the incident surface 122.

On the other hand, the light incident to the remaining portion other than the edge of the incident surface 122 is a total reflection inside the light guide plate 120 while hitting the reflective projections 124 formed on the lower surface of the light guide plate 120, the light guide plate ( Reflected toward the upper surface of the 120 is emitted from the light guide plate (120).

At this time, since the edge of the incident surface 122 and the light blocking step 154 are in close contact with each other, the light is not collected at the edge of the incident surface 122 and the lamp assembly cannot be incident into the light guide plate 120. Bright light is not emitted from the portion adjacent to 140. Therefore, bright band-shaped bright lines are not generated in a portion adjacent to the lamp assembly 140, thereby improving light uniformity of the liquid crystal display device, and not being diffused when the light incident from the reflector 124 is reflected, the light guide plate 120. High brightness can be obtained because it is emitted to the upper surface of the as is.

On the other hand, the light blocking step 154 not only blocks light from entering the edge of the incident surface 122 but also acts as a locking step of the light guide plate 120, so that when the shock or vibration is applied from the outside of the liquid crystal display, Even when the 120 flows due to the gap formed between the frames, the light guide plate 120 may not be pushed toward the lamp 210 due to the light blocking step 154.

The second embodiment of the present invention has the backlight assembly 140 having the same configuration as the first embodiment, and uses the light blocking cushion 130 to prevent the light collected by the edge of the light guide plate 120 from being incident. .

Although the second embodiment may completely block light incident to the edge of the incident surface 122 as in the first embodiment, some light may be incident to the edge of the light guide plate 120 to increase the light efficiency. .

 Hereinafter, the light guide plate 120 and the lamp assembly 140 among the components of the backlight assembly 100 according to the second embodiment and the light blocking cushion 130 which is the core of the present invention will be described in detail.

In the light guide plate 120 according to the second embodiment, as in the first embodiment, the edges of the incident surface 122 of the light guide plate 120 facing the lamp assembly 140 are formed at right angles and face the reflective sheet. A plurality of triangular reflective protrusions 124 having a predetermined height is formed on the lower surface of the 120, and these reflective protrusions 124 extend along the longitudinal direction of the lamp assembly 140.

In addition, the lamp assembly 140 wraps around the outer circumferential surface of the lamp 142 to reflect the light emitted from the lamp 142 and the light emitted from the lamp 142 toward the light guide plate 120 as shown in FIG. 5. Inverter (not shown) having an open side and having a lamp cover 150 fitted to the incident surface 122 of the light guide plate 120, and an electric power connected to the lamp 142 by a wire to supply power to the lamp 142. It is composed of

Here, the overall height of the lamp cover 150 is slightly higher than the height of the incident surface 122 of the light guide plate 120.

In addition, the light blocking cushion 130 according to the second embodiment is installed between the lamp cover 150 and the light guide plate 120 as shown in FIG. 5, and surrounds the edge of the incident surface 122 to reduce the amount of light. One end of the light blocking cushion 130 protrudes from the light guide plate 120 toward the lamp 142 by a predetermined length so as to be adjusted or blocked, and is installed along the longitudinal direction of the lamp 142.

This, the light blocking cushion 130 should have an elastic force that can be contracted when pressure is applied from the outside, it is preferable to use a translucent brown cushion so that a small amount of light is incident on the edge of the incident surface (122). Do.

In addition, when the light is to be prevented from entering the edge of the incident surface 120 as in the first embodiment, a black-based cushion that can completely absorb the light is used.

Referring to the assembly process of the lamp assembly 140, the light guide plate 120 and the light blocking cushion 130 according to the second embodiment, the upper and lower surfaces of the light guide plate 120 to which the lamp cover 150 is fitted Alternatively, the light blocking cushion 130 may be attached to one of the inner surfaces of the lamp cover 150 facing the light guide plate 120. Here, the light blocking cushion 130 is attached to the inner surface of the lamp cover 150 and the light blocking cushion 130 is formed of a translucent material as an example.

When attaching the light blocking cushion 130 to the inner surface of the lamp cover 150, one end of the light blocking cushion 130 must be attached to protrude from the light guide plate 120 toward the lamp 142 by a predetermined length.

As such, when the light blocking cushions 130 are attached to the upper and lower surfaces of the lamp cover 150, the light blocking cushions 130 are fitted to the lamp cover 150 at the incident surface of the light guide plate 120. At this time, the portion of the light blocking cushion 150 which is in contact with the light guide plate 120 is pressed by the pressure applied from the light guide plate 120 and the lamp cover 150, and the thickness thereof becomes thin. However, since pressure is not applied to one end of the light guide plate 120 protruding toward the lamp 142 by a predetermined length, the original thickness of the light blocking cushion 130 is maintained as it is.

Therefore, as shown in FIG. 5, since the thickness of the light blocking cushion 130 suddenly increases at the boundary between the portion where the pressure is applied and the portion where the thickness is not applied, and the portion where the pressure is not applied, the light blocking cushion 130 is formed on the incident surface ( It will wrap around the edge of 122).

As described above, when the edge of the incident surface 122 is wrapped by the light blocking cushion 130, some of the light emitted from the lamp 142 and transmitted to the edge of the incident surface 122 is absorbed, and the other part is The light is incident into the light guide plate 120 through the corners.

As such, light incident on the light guide plate 120 through the remaining entrance surface 122 except for the edge or the edge of the incident surface 122 is totally reflected inside the light guide plate 120 and is formed on the lower surface of the light guide plate 120. When hit with the reflective protrusions 124 is reflected toward the upper surface of the light guide plate 120 to exit the light guide plate 120.

Here, since only a part of the light transmitted to the edge of the incident surface 122 is incident to the light guide plate 120 through the light blocking cushion 130, except for the amount of light incident from the edge of the incident surface 122 except for the corner Since the amount of light incident through the incident surface 122 is about the same, a bright line is not generated in a portion adjacent to the lamp assembly 140.

Incident surface formed at right angles as shown in FIG. 6 without using a light blocking portion such as the light blocking step 154 or the light blocking cushion 130 as in the third and first and second embodiments of the present invention. The edge of 122 is processed into a round shape.

As such, when the edge of the incident surface 122 is processed into a round shape, light is not collected at the edge of the incident surface 122, and thus, the incident surface of the incident surface 122 except for the brightness or the edge of the light incident through the edge of the incident surface 122. The bright line is not generated because the brightness of the light incident through the 122 is about the same.

As described above, according to the present invention, bright bright lines are generated in a portion adjacent to the lamp assembly by covering the edges of the entrance face facing the lamp assembly or by processing the round shape to block light incident to the edges or reduce the amount of light. It is effective to improve the uniformity of the light by preventing it.

In addition, when the light guide plate flows due to impact or vibration applied to the liquid crystal display, the light blocking member prevents the light guide plate from being pushed toward the lamp, thereby preventing the lamp from being damaged due to a collision between the light guide plate and the lamp.

Claims (9)

A reflection sheet inserted into a storage space of the frame and reflecting light in a direction in which the LCD panel is installed; A light guide plate disposed on an upper surface of the reflective sheet, and having a reflective protrusion formed on the lower surface of the reflective sheet to face the incident light toward the LCD panel; An edge of an incidence surface of the light guide plate disposed on at least one side of the light guide plate, the lamp emitting light, and one side facing the light guide plate while surrounding the lamp, being fitted into the light guide plate and facing the lamp; A lamp assembly having a light cover to surround the light reflecting light emitted from the lamp toward the light guide plate; And And an optical sheet installed on the light guide plate to increase brightness of the light transmitted from the light guide plate and transmit the light to a rear surface of the LCD panel. delete The light blocking part of claim 1, wherein the height of the lamp insertion portion into which the lamp is inserted is lower than the thickness of the incident surface, and the height of the light guide plate insertion portion into which the light guide plate is inserted is higher than the thickness of the incident surface. And generating a step on each of the top and bottom surfaces of the lamp cover. The method of claim 1, wherein the light blocking portion is formed by protruding the upper surface and the lower surface of the lamp cover toward the lamp at the boundary between the lamp insertion portion into which the lamp is inserted and the light guide plate insertion portion into which the light guide plate is inserted. Backlight assembly of liquid crystal display. delete delete delete delete A reflection sheet inserted into a storage space of the frame and reflecting light in a direction in which the LCD panel is installed; It is installed on the upper surface of the reflective sheet, the lower surface facing the reflective sheet is formed with reflection projections for exiting the light incident to the LCD panel, the edges of the incident surface to which the light is incident in a round shape Processed light guide plate; A lamp installed on the incidence surface side and having a lamp that emits light and a lamp cover which surrounds the lamp and faces one side of the light guide plate while surrounding the lamp and reflects the light emitted from the lamp toward the light guide plate assembly; And And an optical sheet installed on the light guide plate to increase brightness of the light emitted from the light guide plate and transmit the light to the rear surface of the LCD panel.

Images