KR20080074575A - Backlight assembly and display device using the same - Google Patents

Abstract

A backlight assembly and a display device having the same are provided to enable a light source cover to have a light guide function as well as a reflection function, thereby effectively supplying most light emitted from a light source unit to an incident surface of a light guide plate. A light guide plate(74) includes one or more incident surfaces and a light emitting surface crossing the incident surface. One or more light source units(76) irradiate light to the incident surfaces. A light source cover(78) has an opening facing the incident surface of the light guide plate, and surrounds the light source unit. The light source cover includes a cover main body unit(781) and a cover light guide unit(783). The cover main body unit surrounds the light source unit. In the cover main body unit, the cover light guide unit is disposed on the surface facing the light source unit.

Description

BACKLIGHT ASSEMBLY AND DISPLAY DEVICE USING THE SAME}

1 is an exploded perspective view of a backlight assembly according to a first embodiment of the present invention.

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

3 is an exploded perspective view illustrating a display device including the backlight assembly of FIG. 1.

FIG. 4 is a partial cross-sectional view of the display device of FIG. 3 taken along line IV-IV.

5 is a partial perspective view illustrating a light guide unit of a light source unit and a light source cover used in a display device according to a second exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

41, 42: driving printed circuit board

44: driving integrated circuit chip package

50: display panel 51: first display panel

52: second display panel 60: fixing member

70 back light assembly 71 support member

72: optical sheet 74: light guide plate

75: storage member 76: light source unit

78: light source cover 79: reflective member

781: cover body portion 782: cover reflection portion

783: Cover light guide part

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight assembly and a display device having the same, and more particularly, to a display device having improved utilization efficiency of light emitted from a light source unit.

There are several types of display devices. Among them, a display device having a liquid crystal display (LCD) panel which has a smaller size, a lighter weight, and an improved performance has been established as a representative display device centering on a rapidly developing semiconductor technology.

Display devices having liquid crystal displays have advantages such as miniaturization, light weight, and low power consumption, and thus have been gradually attracting attention as an alternative means of overcoming the disadvantages of conventional cathode ray tubes (CRTs). Nowadays, almost all information processing is required, which is installed in small and medium products such as mobile phones, personal digital assistants (PDAs), and portable multimedia players (PMPs) that require display devices, as well as monitors and TVs, which are medium and large products. It is attached to the apparatus and used.

Since the liquid crystal display panel does not emit light by itself, the display device requires a backlight assembly that supplies light to the rear surface of the liquid crystal display panel. In general, the backlight assembly includes various components such as a light source unit, a light source cover, a light guide plate, a reflective member, and the like.

The light source unit is disposed opposite to the incident surface of the light guide plate. The light source cover surrounds and protects the light source unit while reflecting the light emitted from the light source unit to the incident surface of the light guide plate. That is, the light emitted from the light source unit is divided into light directed directly to the incident surface of the light guide plate and light directed to the light source cover. Light directed to the light source cover is reflected by the light source cover and directed to the incident surface of the light guide plate.

However, in the conventional display device, a large amount of light emitted from the light source unit and directed toward the light source cover is repeated after being reflected between the light source cover and the light source unit and in the light source cover. Therefore, there is a problem that the utilization efficiency of the light emitted from the light source unit is inferior.

Accordingly, an object of the present invention is to provide a backlight assembly having improved utilization efficiency of light emitted from a light source unit.

Another object of the present invention is to provide a display device including the backlight assembly.

A backlight assembly according to the present invention for achieving the above object comprises a light guide plate including at least one incident surface and an exit surface intersecting the incident surface, at least one light source unit for irradiating light to the incident surface; And a light source cover surrounding the light source unit having an opening facing the incident surface of the light guide plate, wherein the light source cover includes a cover body part surrounding the light source unit, and the cover body part facing the light source unit. And a cover light guide disposed on the surface.

The cover light guide part may guide light directed from the light source unit to the cover body part to the light guide plate adjacent to an end portion of the cover light guide part.

The light source cover may further include a cover reflection part disposed between the cover body part and the cover light guide part.

The cover reflection part may be coated on a surface of the cover body part that faces the light source unit.

The cover main body may be made of a material including a reflective material on a surface facing the light source unit.

In the backlight assembly, at least one end of the cover light guide part may face an incident surface of the light guide plate.

The cover light guide part may have a sawtooth shape in which a surface facing the incident surface of the light guide plate is continuous with a plurality of recesses and a plurality of protrusions.

The sawtooth may have a groove formed in a direction crossing the longitudinal direction of the light source unit.

The light source unit may be any one of a cold cathode fluorescent lamp (CCFL), an external electrode flourscent lamp (EEFL), and a hot cathode fluorescence lamp (HCFL).

In addition, the display device according to the present invention includes a display panel for displaying an image, a light guide plate including an emission surface facing the display panel and at least one entrance surface intersecting the emission surface, and irradiating light to the entrance surface. At least one light source unit and a light source cover surrounding the light source unit with an opening facing the incident surface of the light guide plate, wherein the light source cover comprises: a cover body portion surrounding the light source unit; The cover light guide part may be disposed on a surface facing the light source unit.

The cover light guide part may guide light directed from the light source unit to the cover body part to the light guide plate adjacent to an end portion of the cover light guide part.

The light source cover may further include a cover reflection part disposed between the cover body part and the cover light guide part.

The cover reflection part may be coated on a surface of the cover body part that faces the light source unit.

The cover main body may be made of a material including a reflective material on a surface facing the light source unit.

In the display device, at least one end of the cover light guide part may face an incident surface of the light guide plate.

The cover light guide part may have a sawtooth shape in which a surface facing the incident surface of the light guide plate is continuous with a plurality of recesses and a plurality of protrusions.

The sawtooth shape may have a groove formed in a direction crossing the longitudinal direction of the light source unit.

The light source unit may be any one of a cold cathode fluorescent lamp (CCFL), an external electrode flourscent lamp (EEFL), and a hot cathode fluorescence lamp (HCFL).

Accordingly, the backlight assembly and the display device having the same may improve light utilization efficiency.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the accompanying drawings, a two side edge type backlight assembly is shown in which the light source units are respectively disposed on both sides of the light guide plate facing each other, but this is merely to illustrate the present invention, The present invention is not limited thereto. Therefore, the present invention can also be applied to a one side edge type backlight assembly in which a light source unit is disposed only on one side of the light guide plate.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and like reference numerals designate like elements throughout the specification.

In addition, in the various embodiments, components having the same configuration will be described in the first embodiment by using the same reference numerals, and in other embodiments, only the configuration different from the first embodiment will be described.

1 shows a backlight assembly 70 according to a first embodiment of the present invention.

As shown in FIG. 1, the backlight assembly 70 includes a light guide plate 74, a light source unit 76, and a light source cover 78. The backlight assembly 70 further includes an optical sheet 72, a reflective member, a support member 71, and a housing member 75.

The light guide plate 74 includes one or more entrance surfaces and an exit surface intersecting the entrance surfaces. In FIG. 1, the light guide plate 74 has two entrance faces and one exit face. The light guide plate 74 emits light incident through the incident surface through the emission surface.

The light source unit 76 irradiates light onto the incident surface of the light guide plate 74. In addition, the light source unit 76 is disposed opposite to the light guide plate 74. In FIG. 1, the display device 100 includes two pairs of light source units 76 facing two incidence surfaces of the light guide plate 74. However, the number of the light source units 76 is not necessarily limited thereto, and various numbers of light source units 76 may be disposed according to the size of the display device 100 and the type of the light source unit 76.

The light source unit 76 includes one of a cold cathode fluorescent lamp (CCFL), an external electrode flourscent lamp (EEFL), and a hot cathode fluorescence lamp (HCFL). Can be used.

The reflective member 79 is disposed adjacent to the opposite surface opposite to the exit surface of the light guide plate 74. The reflecting member 79 reflects light incident on the incident surface of the light guide plate 74 and directed toward the opposite surface of the emitting surface. Therefore, the light reflected by the reflecting member 79 is emitted through the emission surface. The reflective member 79 reduces the loss of light and assists light diffusion to improve the uniformity of the light emitted from the exit surface of the light guide plate 74.

The optical sheets 72 further improve the luminance characteristics of the light emitted from the exit surface of the light guide plate 74. In other words, the light passing through the optical sheets 72 is more uniformly spread and the brightness is enhanced. The optical sheets 72 may include sheets of various functions, such as a diffusion sheet, a prism sheet, a brightness enhancement sheet, and a protective sheet.

The light source cover 78 surrounds the light source unit 76 with an opening facing the incident surface of the light guide plate 74. One edge of the light guide plate 74 having the incident surface is inserted into at least an opening of the light source cover 78.

The light source cover 78 surrounds and protects the light source unit 76, and reflects and guides the light emitted from the light source unit 76 to the incident surface of the light guide plate 74. That is, the light emitted from the light source unit 76 is divided into light directed directly to the incident surface of the light guide plate 74 and light directed toward the light source cover 78. The light source cover 78 transmits the light directed from the light source unit 76 to the light source cover 78 to the incident surface of the light guide plate 74 with maximum loss.

The housing member 75 houses the light guide plate 74, the light source unit 76, the light source cover 78, the reflective member 79, the optical sheets 72, and the like. The support member 71 is coupled to the housing member 75 to guide the light guide plate 74, the light source unit 76, the light source cover 78, the reflective member 79, and the optical sheet (housed in the accommodation member 75). 72) Secure the back.

In FIG. 1, although both the receiving member 75 and the supporting member 71 are shown as being used, this is merely to illustrate the present invention, but the present invention is not limited thereto. Therefore, the support member 71 may be omitted. When the support member 71 is omitted, the housing member 75 performs the role of the first support member 71 together.

Although not shown in FIG. 1, an inverter circuit board is provided on the rear surface of the housing member 75. The inverter circuit board is electrically connected to the light source unit 76 through a wire, a socket, or the like. The inverter circuit board drives the light source unit 76 by transforming external power to a constant voltage level and then transferring the external power to the light source unit 76.

Referring to FIG. 2, a characteristic structure of the backlight assembly 70 according to the first embodiment of the present invention will be described in detail with reference to the light source cover 78.

As shown in FIG. 2, the light source cover 78 includes a cover main body 781 surrounding the light source unit 76 and a cover disposed on a surface of the cover main body 781 facing the light source unit 76. A light guide portion 783 is included.

The light source cover 78 further includes a cover reflector 782 disposed between the cover main body 781 and the cover light guide portion 782. Here, the cover reflector 782 is coated on a surface of the cover body 781 that faces the light source unit 781. However, the present invention is not necessarily limited thereto. Accordingly, the cover body 781 may be made of a material having a reflective function, and the cover reflector 782 may be omitted. At this time, the cover main body 781 is made of a material including a reflective material on the surface facing the light source unit 76.

The cover light guide portion 783 has one or more ends facing the incident surface of the light guide plate 74. In FIG. 2, both ends of the cover light guide portion 783 face the incident surface of the light guide plate 74. The cover light guide portion 783 guides the light from the light source unit 76 to the cover body portion 781 to the light guide plate 74 adjacent to the end of the cover light guide portion 783. Cover light guide portion 783 is made of a material substantially the same as the material of the known light guide plate 74, such as polymethyl methacrylate (PMMA).

By such a configuration, the backlight assembly 70 may improve utilization efficiency of light emitted from the light source unit 76.

Specifically, some of the light emitted from the light source unit 76 toward the light source cover 78 is reflected by the cover reflector 782 of the light source cover 78 to be directed toward the incident surface of the light guide plate 74. In addition, some of the light emitted from the light source unit 76 in the direction of the light source cover 78 is guided by the cover light guide portion 783 of the light source cover 78 and is transmitted to the incident surface of the light guide plate 74.

As described above, the light source cover 78 not only reflects light but also has a light guiding function, thereby undergoing frequent reflection process between the light source cover 78 and the light source unit 76 and within the light source cover 78. It can be prevented from extinction.

That is, since the cover light guide portion 783 of the light source cover 78 guides and transmits light, unnecessary reflection of light can be reduced.

In FIG. 2, an arrow indicates an example of a path through which light emitted from the light source unit 76 is transmitted to the light guide plate 74 through the cover light guide portion 783 of the light source cover 78.

Accordingly, the backlight assembly 70 may greatly improve the luminance of light emitted from the exit surface of the light guide plate 74 and passed through the optical sheets 72. Accordingly, if necessary, the backlight assembly 70 may simplify some configurations by omitting some sheets of the optical sheets 72. In addition, the backlight assembly 70 may reduce the brightness of the light source unit to lower power consumption.

3 and 4 illustrate the display device 100 having the backlight assembly 70 of FIGS. 1 and 2.

3 and 4 illustrate a liquid crystal display panel as an embodiment of the display panel 50 used in the display device 100, this is merely to illustrate the present invention and the present invention is not limited thereto. Kinds of light receiving display panels can be used.

The display device 100 includes the backlight assembly 70 of FIG. 1, which greatly supplies light, and the display panel 50, which receives light and displays an image. In addition, the display device 100 may further include a cover member 60 to fix and support the display panel 50 on the backlight assembly 70, and may further include other necessary parts.

In addition, the display device 100 includes a plurality of driving integrated circuit chip packages 41 and 42 and a driving printed circuit board 44 that are electrically connected to the display panel 50 to transmit driving signals. Here, the driving integrated circuit chip packages 41 and 42 may be formed of a chip on film package (COF) or a tape carrier package (TCP).

The driving integrated circuit chip packages include a gate driving integrated circuit chip package 41 and a data driving integrated circuit chip package 42. The gate driving integrated circuit chip package 41 is attached to one edge of the display panel 50 to supply a gate signal to the display panel 50. The data driving integrated circuit chip package 42 is attached to the other side of the display panel 50 adjacent to the one side to supply the other signal including the data signal to the display panel 50.

The display panel 50 includes a first display panel 51 and a second display panel 53 disposed to face the first display panel 51 with the liquid crystal layer (not shown) therebetween. The first display panel 51 may be a rear substrate, the second display panel 53 may be a front substrate, and the second display panel 53 may have a smaller size than that of the first display panel 51. Here, the driving integrated circuit chip packages 41 and 42 are attached to an edge of the first display panel 51, one side of which is not overlapped with the second display panel 53, and is connected to the display panel 50. At least one of the driving integrated circuit chip packages 41 and 42 may be connected to the driving printed circuit board 44 at the other side.

In FIG. 3, one driving integrated circuit chip package 42 is connected to the driving printed circuit board 44, but the present invention is not limited thereto. Therefore, another driving integrated circuit chip package 41 may also be connected to another driving printed circuit board (not shown).

The driving printed circuit board 44 generates various control signals and transmits a digital signal input from the outside to the data driving integrated circuit chip package 42. The integrated circuit chip of the data driving integrated circuit chip package 42 converts a digital signal into an analog form based on various control signals received from the driving printed circuit board 44, and then supplies it to the display panel 50 for display. The panel 50 is driven.

Polarizers 55 and 57 are attached to the front surface of the second display panel 53 and the rear surface of the first display panel 51 to linearly polarize the visible light supplied from the backlight assembly 70.

A plurality of thin film transistors (TFTs), color filters, pixel electrodes, and common electrodes are formed on the first display panel 51 and the second display panel 53. The liquid crystal layer is disposed between the pixel electrode and the common electrode.

By such a configuration, when the thin film transistor as the switching element is turned on, an electric field is formed between the pixel electrode and the common electrode. The liquid crystal array angle of the liquid crystal layer disposed between the first display panel 51 and the second display panel 53 is changed by this electric field. As a result, the display panel 50 obtains a desired image by the light transmittance changed.

The display panel 50 faces the exit surface of the light guide plate 74. An optical sheet 72 is disposed between the light guide plate 74 and the display panel 50. The display panel 50 is supported by the support member 71. The cover member 60 is combined with the support member 71 and the storage member 75 to fix the display panel 50.

By such a configuration, the display device 100 can improve the utilization efficiency of the light emitted from the light source unit 76. Accordingly, the display device 100 may omit some sheets of the optical sheets 72 to simplify the configuration or reduce the brightness of the light source unit 76 to reduce the power consumption.

A second embodiment of the present invention will be described with reference to FIG. FIG. 2 partially shows the cover light guide portion 784 of the light source unit 76 and the light source cover 78 (shown in FIG. 4) for ease of explanation.

As shown in FIG. 5, the cover light guide portion 784 has a sawtooth shape 786 in which a surface facing the incident surface of the light guide plate 74 is formed by a plurality of recesses 787 and a plurality of protrusions 788. Include. Here, the sawtooth shape 786 is formed with a groove in the direction crossing the longitudinal direction of the light source unit 76.

By such a configuration, the light guided by the cover light guide part 784 can be more effectively transmitted to the light guide plate 74. That is, light in the cover light guide part 784 may be easily transmitted to the light guide plate 74.

Although the present invention has been described above, it will be readily understood by those skilled in the art that various modifications and variations are possible without departing from the spirit and scope of the claims set out below.

As described above, the backlight assembly according to the present invention can improve the use efficiency of the light emitted from the light source unit.

That is, the light source cover has not only a reflection function but also a light guiding function, so that most of the light emitted from the light source unit can be effectively supplied to the incident surface of the light guide plate.

Therefore, the backlight assembly can simplify the configuration by omitting some sheets of the optical sheet. In addition, the backlight assembly may reduce the brightness of the light source unit to consume low power.

In addition, the light guided by the cover light guide part can be more effectively transmitted to the light guide plate.

In addition, a display device including the backlight assembly may be provided.

Claims (18)

In a backlight assembly, A light guide plate including at least one incident surface and an exit surface intersecting the incident surface; At least one light source unit for irradiating light onto the incident surface; A light source cover surrounding the light source unit with an opening facing the incident surface of the light guide plate; The light source cover, A cover body part surrounding the light source unit; And a cover light guide part disposed on a surface of the cover body part that faces the light source unit. In claim 1, And the cover light guide part guides the light from the light source unit to the cover body part to the light guide plate adjacent to an end portion of the cover light guide part. In claim 2, The light source cover further comprises a cover reflector disposed between the cover body portion and the cover light guide portion. In claim 3, And the cover reflecting portion is coated on a surface of the cover body portion that faces the light source unit. In claim 2, And the cover body portion is made of a material including a reflective material on a surface facing the light source unit. The method according to any one of claims 1 to 5, And at least one end of the cover light guide portion faces an incident surface of the light guide plate. In claim 6, The cover light guide part is a backlight assembly, characterized in that the surface facing the incidence surface of the light guide plate has a sawtooth shape in which a plurality of concave portions and a plurality of protrusions are continuous. In claim 7, The sawtooth shape is a backlight assembly, characterized in that the groove is formed in a direction crossing the longitudinal direction of the light source unit. In claim 6, The light source unit is a backlight, characterized in that any one of a cold cathode fluorescent lamp (CCFL), an external electrode flourscent lamp (EEFL) and a hot cathode fluorescence lamp (HCFL) assembly. On the display device, A display panel displaying an image, A light guide plate including an emission surface facing the display panel and at least one entrance surface intersecting the emission surface; At least one light source unit for irradiating light onto the incident surface; A light source cover surrounding the light source unit with an opening facing the incident surface of the light guide plate; The light source cover, A cover body part surrounding the light source unit; And a cover light guide part disposed on a surface of the cover body part facing the light source unit. In claim 10, And the cover light guide unit guides the light from the light source unit toward the cover body to the light guide plate adjacent to an end portion of the cover light guide unit. In claim 11, The light source cover further includes a cover reflector disposed between the cover main body and the cover light guide part. In claim 12, And the cover reflector is coated on a surface of the cover main body that faces the light source unit. In claim 11, And the cover main body is made of a material including a reflective material on a surface facing the light source unit. The method according to any one of claims 10 to 14, And at least one end of the cover light guide part faces an incident surface of the light guide plate. The method of claim 15, And the cover light guide part has a sawtooth shape in which a surface opposing the incident surface of the light guide plate is formed with a plurality of recesses and a plurality of protrusions. The method of claim 16, Wherein the sawtooth has a groove formed in a direction crossing the longitudinal direction of the light source unit. The method of claim 15, The light source unit may be any one of a cold cathode fluorescent lamp (CCFL), an external electrode flourscent lamp (EEFL), and a hot cathode fluorescence lamp (HCFL). Device.

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