KR20100061326A - Backlight unit and display apparatus comprising the same - Google Patents

Abstract

PURPOSE: A backlight unit and display device for maintaining the luminance of a light source regardless of the deformation of a light guide plate is provided to maintain a distance between an optical source section and a light guide plate. CONSTITUTION: A light source unit(110) includes one or more light source. One or more light source is arranged according to the prescribed direction. A light guide plate(120) transfers the light from the optical source section in the prescribed direction. An elastic member(160) elastically biases the optical source section to the light guiding plate side. The optical source section comprises the interval maintenance unit.

Description

BACKLIGHT UNIT AND DISPLAY APPARATUS COMPRISING THE SAME}

The present invention relates to a backlight unit and a display device including the same. More particularly, the backlight may maintain a constant distance between the light source unit and the light guide plate regardless of expansion or contraction of the light guide plate due to heat, thereby ensuring a necessary amount of light. It is an object of the present invention to provide a unit and a display device including the same.

The backlight unit may be classified into two types, a direct type and an edge type, according to the position of the light source.

The direct type backlight unit includes a reflector positioned at the bottom of the lamp to reflect light, and a light source located at the bottom of the liquid crystal panel to direct light to the front side of the liquid crystal panel, and to collect light irradiated at the top of the lamp. It consists of an optical sheet etc. to make it diffuse. In addition, since a large number of light sources can be provided and light utilization efficiency is high, it is mainly used for a large screen liquid crystal display device requiring high brightness.

On the other hand, the edge type backlight unit typically includes a light guide plate on the side of the light source to guide the light of the light source in the direction of the liquid crystal panel. The edge type is disadvantageous in that the luminance decreases when the liquid crystal display is enlarged, but it is advantageous in thinning. The light guide plate scatters light to make it uniform, and a reflecting plate is disposed on the bottom surface of the light guide plate. In addition, the upper surface of the light guide plate is formed with a pair of prism sheets for switching the light path, and to improve the uniformity of the light incident on the liquid crystal panel is formed.

The light guide plate is usually made of PMMA (Polymer Methyl Methacrylate). PMMA materials are characterized by expansion and contraction in response to heat and humidity, and the coefficient of thermal expansion is also large among plastic materials.

 On the other hand, in the case of a large backlight unit, LEDs should be arranged as close as possible to the light guide plate to secure sufficient light amount. This is because the light efficiency decreases as the distance between the LED and the light guide plate increases. When the LED edge type is adopted in a large backlight unit larger than 40 inches, the size of the light guide plate also increases, thereby increasing the length change of expansion or contraction due to temperature and humidity changes. Therefore, when the LED is arranged close to the light guide plate for light efficiency, the light guide plate may be in contact with the LED due to expansion in a high temperature operation environment. There is a difficulty in securing the amount of light.

The present invention solves the problem of adjusting the gap between the light guide plate and the LED that occurs during the design of a large LED edge type backlight unit.

In addition, the present invention provides a backlight unit capable of maintaining the brightness of a light source irrespective of deformation of the light guide plate and a display device including the same.

According to the present invention, there is provided a backlight unit comprising: a light source unit having at least one light source arranged along a predetermined direction; A light guide plate transferring light emitted from the light source unit in a predetermined direction; An elastic member may be configured to elastically bias the light source to the light guide plate, and the light source may include a gap maintaining part for maintaining a constant distance between the light source and the light guide plate.

The light source unit may further include a plurality of point light sources and a point light source substrate on which the point light source is mounted, and the gap maintaining unit may extend from the point light source substrate in the direction of the light guide plate.

The gap maintaining part may be provided integrally with the point light source substrate.

”, “ㅏ”형상 중 어느 하나 일 수 있다. At this time, the cross section of the point light source substrate and the gap maintaining portion may have a "c" shape, an "b" shape, and "

”Or“ 형 ”shape.

And an accommodating member accommodating the light source part and the light guide plate, wherein the elastic member is provided between the accommodating member and the light source part, and the elastic member is coupled to the accommodating member and the light source part to correspond to deformation of the light guide plate. It is desirable to have.

The elastic member may include at least one of a coil spring, rubber, graphite tape, graphite sheet and sponge. Of course, the elastic member is not limited to a specific configuration and material as long as it can elastically bias the light source in response to deformation of the light guide plate.

The light source may be disposed along the side of the light guide plate.

The light source may include a light emitting diode device.

On the other hand, the display device according to an embodiment of the present invention, the image receiving unit for receiving a video signal; A signal receiver which processes the received video signal; A display panel displaying the processed video signal; And a backlight unit for providing light to the display panel, wherein the backlight unit comprises: a light source unit having at least one light source arranged along a predetermined direction; A light guide plate transferring light emitted from the light source unit in a predetermined direction; An elastic member may be configured to elastically bias the light source to the light guide plate, and the light source may include a gap maintaining part for maintaining a constant distance between the light source and the light guide plate.

As described above, according to one embodiment of the present invention, a backlight unit capable of maintaining the brightness of a light source regardless of deformation of a light guide plate and a display apparatus including the same are provided.

In addition, according to an embodiment of the present invention, there is provided a backlight unit capable of maintaining a constant distance between a light source unit and a light guide plate, and a display apparatus including the same.

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

1A and 1B are cross-sectional views of a backlight unit according to an exemplary embodiment of the present invention, illustrating a contraction of an elastic member according to deformation of a light guide plate.

As illustrated, the backlight unit according to the present exemplary embodiment includes the light source unit 110, the light guide plate 120, the optical sheet 130 arranged on the upper part of the light guide plate 120, and the reflector plate arranged under the light guide plate 120. 140, an accommodating member 150 for accommodating them. In addition, the backlight unit further includes an elastic member 160 provided in the accommodation member 150 and the light source unit 110. The backlight units according to the present exemplary embodiment have an edge type, and the light source units 110 are arranged in a line in a specific direction.

The light guide plate 120 has a light source unit 110 arranged at one side such that light emitted from the light source unit 110 may be incident. The light guide plate 120 is usually made of an acrylic resin such as polymethyl methacrylate and serves to uniformly supply light from the light source unit 110 toward the optical sheet 130. The light guide plate 120 is generally rectangular, but is not limited thereto. The light guide plate 120 may have various shapes according to the shape of the panel to which light is supplied.

The optical sheet 130 may include a diffusion plate, a prism film, a protective film, and the like, and uniformly diffuse the light emitted from the light guide plate 120.

The reflective plate 140 reflects the light incident to the lower portion of the light guide plate 120 to reflect the light back to the optical sheet 130 and supplies the light to the light guide plate 120. The reflector 140 may be made of polyethylene terephthalate (PET) or polycarbonate (PC), and may be coated with silver or aluminum.

FIG. 2 is a detailed view illustrating the light source unit 110 and the elastic member 160 in detail by enlarging A of FIG. 1A. As illustrated, the light source unit 110 includes a point light source 111 and a point light source 111 as light sources. ) Includes a point light source substrate 112 mounted thereon, and gap holding portions 113 and 114 extending from the point light source substrate 112. The elastic member 160 is coupled to the light source unit 110 at one side of the light source unit 110.

The point light source 111 is mounted on a bar-shaped point light source substrate 112 and includes a plurality of light emitting diodes. The temperature of the point light source 111 may rise to several tens of degrees due to light emission. The point light source 111 may form a group of a plurality of light emitting diodes emitting different colors, and may be provided as a light emitting diode emitting white light. The point light source 111 may be implemented as a laser diode in addition to the light emitting diode.

The point light source substrate 112 may be implemented as a circuit board on which a circuit pattern for supplying power to the point light source 111 is formed, and may be made using aluminum having excellent heat transfer rate as a main material.

The gap maintaining parts 113 and 114 extend from the point light source substrate 112 in the direction of the light guide plate 120 to maintain a constant distance between the light guide plate 120 and the point light source 111. As shown, the interval maintaining parts 113 and 114 according to the present exemplary embodiment have a “c” shaped cross section opened in the direction of the light guide plate 120 while receiving the point light source 111 together with the point light source substrate 112. Configure The gap maintaining parts 113 and 114 may be provided integrally with the point light source substrate 112. Of course, the point light source substrate 112 and the interval maintaining parts 113 and 114 may be connected to each other so as to be coupled to each other.

End portions of the gap maintaining portions 113 and 114 extending from the point light source substrate 112 are in contact with one surface of the light guide plate 120, and the point light sources 111 and the light guide plate are separated by the gap maintaining portions 113 and 114. A constant interval G1 is maintained between 120. That is, even when the light guide plate 120 is expanded by the gap maintaining units 113 and 114, the gap between the point light source 111 and the light guide plate 120 disposed in the direction in which the light guide plate 120 is expanded does not become narrow and maintains G1. do. According to the present embodiment, the space keeping parts 113 and 114 and the light guide plate 120 are in contact with each other but are not bonded to each other.

The elastic member 160 is provided between the light source unit 110 and the storage member 150, and both ends thereof are fixed to the light source unit 110 and the storage member 150. The elastic member 160 elastically biases the light source unit 110 in the direction of the light guide plate 120, and supports the light source unit 110 while its length changes in association with the expansion or contraction of the light guide plate 120. If the light guide plate 120 is expanded and pressure is applied in the direction of the light source unit 110, the elastic member 160 will contract. If the light guide plate 120 is contracted, the elastic member 160 will expand and expand the light source unit 110. Will support. As shown in FIG. 1A, when the length of the elastic member 160 is d1, the gap between the point light source 111 and the light guide plate 120 is maintained by G1 as described above. If the light guide plate 120 expands in the direction of the light source unit 110 by heat or humidity, and the length of the light guide plate 120 is increased by about X, the elastic member 160 contracts as shown in FIG. 1B to have a length d2 smaller than d1. Even if the light guide plate 120 is deformed in this way, the distance between the point light source 111 and the light guide plate 120 is kept constant. On the contrary, when the light guide plate 120 is contracted in the state of FIG. 1B, the elastic member 160 may increase in length so that the light source unit 110 may be appropriately supported between the accommodation member 150 and the light guide plate 120.

3 is a cross-sectional view of a conventional backlight unit. As shown, the point light source 10 is fixed to the inner side of the housing member 150. The distance between the point light source 10 and the light guide plate 120 is G2, but when the light guide plate 120 is contracted or expanded, the distance between the point light source 10 and the light guide plate 120 will be changed. That is, the distance between the point light source 10 and the light guide plate 120 will be changed to correspond to the deformation of the light guide plate 120, which means a change in brightness of light. In addition, when the light guide plate 120 is inflated and the light guide plate 120 and the point light source 10 are in contact with each other, the light guide plate 120 may be deformed due to heat generation of the point light source 10, and luminance unevenness may occur.

According to the present exemplary embodiment, the distance between the point light source 111 and the light guide plate 120 is kept constant, so that the luminance of light emitted from the point light source 111 to the light guide plate 120 can be kept constant and the light guide plate ( 120 may flexibly support the light source unit 110 in conjunction with the deformation.

The elastic member 160 according to the present embodiment is a coil spring as shown. The material and the structure of the elastic member 160 are not limited thereto, and may be provided between the light source unit 110 and the accommodation member 150 to include a rubber or a sponge if an elastic bias can be applied to the light source unit 110. The elastic member 160 may be provided in plural, and has heat resistance such that elasticity can be maintained in heat generated by the point light source 111.

According to another embodiment of the present invention, the light source may be implemented as a line light source or a surface light source such as a lamp rather than a point light source.

In addition, according to another embodiment of the present invention, the interval maintaining portions 113 and 114 formed integrally with the point light source substrate 112 may be provided as a clamp and coupled to the light guide plate 120.

In addition, according to another embodiment of the present invention, the backlight unit may be configured as a direct type rather than an edge type. In this case, the backlight unit includes a light guide plate and a light source unit arranged on the rear surface of the light guide plate. In addition, the light guide plate and the light source may be provided between the gap maintaining portion and the elastic member provided between the light source and the lower chassis.

4 is a perspective view of a display device according to an embodiment of the present invention, Figure 5 is a control block diagram of the display device.

 As shown, the display apparatus includes a display panel 200 and a backlight unit 100 provided below the display panel 200 to provide light to the display panel 200, and includes an image receiving unit 300 and a signal. It further includes a processing unit (400).

As shown in FIG. 4, the reflective sheet 140 is accommodated in the accommodating member 150, and the light source unit 110, the light guide plate 120, the optical member 130, and the accommodating member 150 are spaced apart from each other. The light guide plate 120 will be arranged between the two point light source substrates 111 shown, and the light emitted from the point light source 111 will be incident to the side of the light guide plate 120. The elastic member 160 formed between the point light source substrate 112 and the accommodation member 150 elastically biases the light source unit 110 toward the light guide plate. Of course, the point light source 111 and the point light source substrate 112 may be arranged along the long side side of the light guide plate 120, or may be additionally arranged along the long side side of the light guide plate 120 in the present configuration. .

The display panel 200 according to the present embodiment is implemented as a liquid crystal panel. The display panel 200 is filled with a liquid crystal layer (not shown) between two substrates, and displays an image by adjusting the arrangement of the liquid crystal layer. The display panel 200 receives light from the backlight unit 100 to display an image in the display area. The display panel 200 includes a panel driver 210 for receiving and displaying an image signal. The signal processing block for providing an image signal to the panel driver 210 is mounted on a board (not shown) together with a power block and stored in the accommodating member 150.

The image receiver 300 of FIG. 5 receives an image to be displayed on the display panel 200. The image receiver 300 receives an RF signal transmitted from a broadcasting station (not shown) when the display apparatus is implemented as a television. Wireless reception may be performed, or an image signal according to composite video, component video, super video, SCART, HDMI (high definition multimedia interface) standard, or the like may be received. Alternatively, when the display device is a computer monitor, the image receiver 300 may be configured to receive a video signal such as a D-SUB, a DVI, or an HDMI standard capable of transmitting an RGB signal according to a VGA method.

The signal processor 400 performs various preset signal processing on the image signal transmitted from the image receiver 300. The type of signal processing performed by the signal processing unit 400 is not limited to a specific process. For example, various decoding, encoding, deinterlacing, frame rate conversion, scaling, noise reduction for image quality improvement, and detail enhancement And the like. The signal processor 400 may be implemented in a separate configuration capable of independently performing each of these processes, or may be implemented in an integrated configuration incorporating various functions.

When the backlight unit 100 intends to implement local dimming, the signal processor 400 may generate a control signal for this and output the control signal to the backlight unit 100. The backlight unit 100 may further include a light source driver (not shown) and a light source controller that receives the control signal and controls the light source driver.

6 is a cross-sectional view of a backlight unit according to another embodiment of the present invention.

The backlight unit according to the present embodiment may include a graphite sheet 161 as an elastic member. The thickness of the graphite sheet 161 may have a range of about 1 to 3 mm. Graphite is a homogeneous material with diamond, and has conductivity and thermal conductivity. The graphite sheet 161 is a natural graphite product refined without addition of additives and has unique characteristics such as heat resistance and chemical resistance, and has excellent flexibility and compression restoring force, that is, elasticity and can be used even at high temperatures. The backlight unit may include a graphite tape in which a surface of the graphite sheet 161 is cut into a predetermined width instead of the graphite sheet 161.

7 is a cross-sectional view of a backlight unit according to another embodiment of the present invention.

”을 갖는다. 즉, 점광원(111)과 도광판(120) 사이의 간격을 일정하게 유지할 수 있는 형상이면 점광원 기판(112)과 간격유지부(161)는 “ㄷ”자 형상이 아니어도 무방하다. 따라서, 간격유지부(161)는 점광원(111)의 하부에서 점광원 기판(112)으로부터 도광판(120) 방향으로 연장될 수 있고, 이 경우 점광원 기판(112)과 간격유지부(161)의 단면은 “ㄴ”자 형상을 갖는다.The gap holding unit 1 according to the present embodiment extends from the point light source substrate 112 toward the light guide plate 120 on the point light source 111. The cross section of the point light source substrate 112 and the space keeping unit 161 is “

Has ”. That is, the point light source substrate 112 and the gap maintaining part 161 may not have a “c” shape as long as the gap between the point light source 111 and the light guide plate 120 can be kept constant. Accordingly, the gap maintaining part 161 may extend from the point light source substrate 112 toward the light guide plate 120 at the lower portion of the point light source 111, in which case the point light source substrate 112 and the gap maintaining part 161 may be extended. The cross section of has the shape of “b”.

8 is a view illustrating a light source unit that may be included in another backlight unit. The light source unit 110 according to the present exemplary embodiment includes a gap maintaining unit 116 that is led from the point light source 111 toward the light guide plate 120. That is, the gap maintaining part 116 does not extend from the edge of the point light source substrate 112 but extends in the direction of the light guide plate 120 on the surface of the point light source substrate 112. The interval maintaining unit 116 may be arranged between the point light sources 111 as shown, or may be arranged between the plurality of point light sources 111. The gap maintaining part 116 may have a cylindrical shape or may have a polygonal pillar shape.

Although some embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that modifications may be made to the embodiment without departing from the spirit or spirit of the invention. . It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

1A and 1B are cross-sectional views illustrating shrinkage of an elastic member according to deformation of a light guide plate of a backlight unit according to an exemplary embodiment of the present invention.

2 is a detailed view of A of FIG. 1A,

3 is a cross-sectional view of a conventional backlight unit;

4 is a perspective view of a display device according to an embodiment of the present invention;

5 is a control block diagram of the display apparatus according to FIG.

6 is a cross-sectional view of a backlight unit according to another embodiment of the present invention;

7 is a cross-sectional view of a backlight unit according to another embodiment of the present invention;

8 is a cross-sectional view of a backlight unit according to another embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: backlight unit 110: light source unit

10, 111: point light source 120: light guide plate

130: optical sheet 140: reflector

150: receiving member 160, 161: elastic member

200: display panel 300: video receiver

400: signal processing unit

Claims (16)

In the backlight unit, A light source unit having at least one light source arranged along a predetermined direction; A light guide plate transferring light emitted from the light source unit in a predetermined direction; An elastic member for elastically biasing the light source to the light guide plate side; The light source unit includes a backlight unit for maintaining a constant distance between the light source and the light guide plate. The method of claim 1, The light source unit, Point light source, Further comprising a point light source substrate on which the point light source is mounted, And the gap maintaining portion extends from the point light source substrate in the direction of the light guide plate. The method of claim 2, And the gap maintaining part is integrated with the point light source substrate. The method of claim 3, The cross section of the point light source substrate and the gap maintaining portion may have a "-" shape, a "b" shape, and an opening in the light guide plate direction.

And a “ㅏ” shape. The method of claim 4, wherein Further comprising a receiving member for receiving the light source and the light guide plate, The elastic member is provided between the housing member and the light source unit, the backlight unit, characterized in that coupled to the housing member and the light source. The method of claim 1, The elastic member is a backlight unit, characterized in that it comprises at least one of coil spring, rubber, graphite tape, graphite sheet and sponge. The method of claim 1, And the light source is disposed along a side surface of the light guide plate. The method of claim 1, And the light source comprises a light emitting diode element. In the display device, An image receiver which receives an image signal; A signal processor which processes the received video signal; A display panel displaying the processed video signal; It includes a backlight unit for providing light to the display panel, The backlight unit, A light source unit having at least one light source arranged along a predetermined direction; A light guide plate transferring light emitted from the light source unit in a predetermined direction; An elastic member for elastically biasing the light source to the light guide plate side; The light source unit includes a display device for maintaining a constant distance between the light source and the light guide plate. 10. The method of claim 9, The light source unit, Point light source, Further comprising a point light source substrate on which the point light source is mounted, And the gap maintaining portion extends from the point light source substrate in the direction of the light guide plate. The method of claim 10, And the gap maintaining part is integrated with the point light source substrate. The method of claim 10, The cross section of the point light source substrate and the gap maintaining portion may have a “C” shape, an “B” shape, “” opened in the light guide plate direction.

And a “ㅏ” shape. 10. The method of claim 9, Further comprising a receiving member for receiving the light source and the light guide plate, The elastic member is provided between the housing member and the light source unit, characterized in that coupled to the housing member and the light source. 10. The method of claim 9, The elastic member includes at least one of the coil spring, rubber, graphite tape, graphite sheet and sponge. 10. The method of claim 9, And the light source is disposed along a side of the light guide plate. 10. The method of claim 9, The light source includes a light emitting diode device.

Images