KR20080016281A - Backlight unit and display device including same - Google Patents

Abstract

The present invention relates to a backlight unit and a display device including the same. A display device according to the present invention includes a display panel; A light source unit disposed on a rear surface of the display panel; An optical sensor unit detecting a color of light generated by the light source unit; A light source driver for supplying power to the light source; And a light source controller for controlling the light source driver to adjust the color of light generated by the light source unit based on the color detected by the light sensor unit. The light sensor unit includes a light sensor and a light receiving hole exposing the light sensor, covering the light sensor. Located in the shielding case and the light receiving hole is characterized in that it comprises a light receiving unit for receiving light from the light source unit. Accordingly, a display device including an optical sensor unit having improved incident light directing characteristics is provided.

Description

BACKLIGHT UNIT AND DISPLAY DEVICE HAVING THE SAME}

1 is an exploded perspective view of a display device according to a first embodiment of the present invention;

2 is an exploded perspective view of an optical sensor unit according to a first embodiment of the present invention;

3 is a cross-sectional view of an optical sensor unit according to a first embodiment of the present invention;

4 is a block diagram illustrating a backlight unit of a display device according to a first exemplary embodiment of the present invention;

5 is a perspective view of main parts of an optical sensor according to a second exemplary embodiment of the present invention.

Explanation of Signs of Major Parts of Drawings

10: upper cover 20: liquid crystal display panel

30: light adjusting member 40: reflecting plate

41: light emitting diode receiving port 51: light emitting diode circuit board

52: light emitting diode 53: light emitting diode group

61: light source control unit 63: light source driving unit

70: optical sensor unit 71: optical sensor circuit board

72: light sensor 73: shielding case

74: light receiving hole 75: light receiving unit

76: support portion 77: incidence portion

80: lower cover 81: bottom

85: sidewall

The present invention relates to a backlight unit and a display device including the same, and more particularly, to a backlight unit including an optical sensor unit having improved incident light directing characteristics and a display device including the same.

Recently, a flat panel display such as a liquid crystal display (LCD), a plasma display panel (PDP), or an organic light emitting diode (OLED) has been developed in place of the conventional CRT.

Among them, the liquid crystal display includes a liquid crystal display panel, and the liquid crystal display panel includes a thin film transistor substrate, a color filter substrate, and liquid crystal injected between both substrates. Since the liquid crystal display panel is a non-light emitting device, a backlight unit for supplying light is disposed on the rear surface of the thin film transistor substrate. Light transmitted from the backlight unit is adjusted according to the arrangement of liquid crystals.

Recently, as a light source used in a backlight unit, a point light source such as a light emitting diode, rather than a line light source such as a lamp, has attracted attention. When a point light source is used as a light source, white light is produced by mixing light of a point light source that emits light of different colors, and then, the white light is supplied to the rear surface of the liquid crystal display panel.

However, it is difficult to control the overall color because the point light sources for each color are driven individually, and the wavelength of light emitted from each point light source changes due to changes in external environment such as temperature increase during driving, making it difficult to supply uniform white light. have. In addition, since the light generated from the point light source is not accurately and uniformly detected by the optical sensor, it is difficult to supply uniform white light.

It is an object of the present invention to provide a backlight unit including an optical sensor unit having improved incident light directing characteristics and a display device including the same.

An object of the present invention is a display panel; A light source unit disposed on a rear surface of the display panel; An optical sensor unit detecting a color of light generated by the light source unit; A light source driver for supplying power to the light source; And a light source controller for controlling the light source driver to adjust the color of light generated by the light source unit based on the color detected by the light sensor unit. The light sensor unit includes a light sensor and a light receiving hole exposing the light sensor, covering the light sensor. It is achieved by a display device characterized in that it comprises a shielding case and a light receiving portion which is located in the light receiving hole and receives the light from the light source.

Here, the lower cover having a bottom and sidewalls to accommodate the light source unit may further include, the optical sensor unit may be located on the sidewalls.

The bottom portion is provided in a substantially rectangular shape having a long side and a short side, and the optical sensor unit may be positioned at a central portion of at least one of sidewalls extending from the long side.

The optical sensor unit may further include an optical sensor circuit board on which the optical sensor is mounted, and the shielding case may further cover the optical sensor circuit board.

Here, the light sensor unit may be located on the inner surface of the side wall such that the light receiving unit faces the light source unit.

The light receiving unit may have a lens shape convex toward the light source unit.

In addition, the light sensor detects the colors of red, green and blue light, respectively, and includes a red sensor, a green sensor and a blue sensor disposed adjacent to each other, the light receiving unit is a support portion accommodated in the light receiving hole, and from the support portion The incident part may extend to be exposed to the outside, and the incident part may include a first convex lens part, a second convex lens part, and a third convex lens part corresponding to the red sensor, the green sensor, and the blue sensor, respectively.

The light source unit may include a green light emitting diode, a red light emitting diode, and a blue light emitting diode disposed adjacent to each other.

The light source controller may control the light source driver for each color of light emitted from the light source.

In addition, the plurality of light sensor units are located at a plurality of points on the side wall to receive light, and the light source controller may control the light source driver by dividing the light source unit by zone.

The display panel may include a liquid crystal display panel.

Another object of the present invention, the light source; An optical sensor unit detecting a color of light generated by the light source unit; A light source driver for supplying power to the light source; And a light source controller for controlling the light source driver to adjust the color of light generated by the light source unit based on the color detected by the light sensor unit. The light sensor unit includes a light sensor and a light receiving hole exposing the light sensor, covering the light sensor. It is achieved by a backlight unit, characterized in that it comprises a shielding case and a light receiving portion which is located in the light receiving hole and receives the light from the light source.

The optical sensor unit may further include an optical sensor circuit board on which the optical sensor is mounted, and the shielding case may further cover the optical sensor circuit board.

The light sensor unit may be disposed such that the light receiving unit faces the light source unit.

In addition, the light receiving unit may have a lens shape convex toward the light source unit.

The light sensor detects the colors of red light, green light and blue light, respectively, and includes a red sensor, a green sensor, and a blue sensor disposed adjacent to each other, and the light receiving part includes a support part accommodated in the light receiving hole and a support part. The incident part may extend to be exposed to the outside, and the incident part may include a first convex lens part, a second convex lens part, and a third convex lens part corresponding to the red sensor, the green sensor, and the blue sensor, respectively.

In addition, the light source unit may include a green light emitting diode, a red light emitting diode, and a blue light emitting diode disposed adjacent to each other.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

In the following embodiment, a light emitting diode is described as an example of the point light source, but the point light source of the present invention is not limited to the light emitting diode. In addition, although a liquid crystal display device is described as an example of the display device, the display device of the present invention is not limited to the liquid crystal display device, but may be applied to other display devices including a backlight unit.

In the liquid crystal display according to the first embodiment, the backlight unit is described as a direct type as an example. However, the backlight unit may be applied to an edge-type backlight unit. The light source unit is described as an example of white light as light to be provided to the liquid crystal display panel, but is not limited thereto.

As shown in FIG. 1, the liquid crystal display device 1 according to the present invention is disposed behind the liquid crystal display panel 20 and the liquid crystal display panel 20 to supply light to the liquid crystal display panel 20. And a backlight unit 90. The liquid crystal display panel 20 and the backlight unit 90 are accommodated in the upper cover 10 and the lower cover 80 which are coupled to each other. The backlight unit 90 includes a light adjusting member 30, a reflector 40, a light source unit 50, a light source controller 61, a light source driver 65, and an optical sensor unit 70.

The liquid crystal display panel 20 includes a thin film transistor substrate 21 on which a thin film transistor is formed and a color filter substrate 22 facing the thin film transistor substrate 21, and a liquid crystal layer between the substrates 21 and 22. (Not shown) is located. The liquid crystal display panel 20 forms a screen by adjusting the arrangement of the liquid crystal layer, but since the liquid crystal display panel 20 is a non-light emitting device, light must be supplied from the light source unit 50 located on the rear surface. One side of the thin film transistor substrate 21 is provided with a driver 25 for applying a drive signal. The driver 25 includes a flexible printed circuit board (FPC) 26 having one side connected to the thin film transistor substrate 21, a driving chip 27 mounted on the flexible printed circuit board 26, and a flexible printed circuit board 26. The driving circuit board 29 is connected to the other side and is connected to the connecting circuit board 28 surrounding the side of the backlight unit 90 and the connecting circuit board 28 and located on the rear surface of the lower cover 80. ). The driver 25 illustrated represents a chip on film (COF) method, and other known methods such as a tape carrier package (TCP) and a chip on glass (COG) may be used. In addition, a part of the driver 25 may be formed on the thin film transistor substrate 21 during the wiring formation process.

The light adjusting member 30 is positioned on the rear surface of the liquid crystal display panel 20. The light adjusting member 30 may include a diffusion plate 31, a prism film 32, and a protective film 33. The diffusion plate 31 is composed of a coating layer including a base plate and beads of beads formed on the base plate. The diffusion plate 31 diffuses the light supplied from the light source unit 50 to make the luminance uniform. The prism film 32 is formed with a triangular prism-shaped prism on the upper surface. The prism film 32 collects light diffused from the diffuser plate 31 in a direction perpendicular to an arrangement plane of the upper liquid crystal display panel 20. Two prism films 32 are usually used, and the micro prisms formed on the prism films 32 are at an angle. The light passing through the prism film 32 is almost vertically progressed to provide a uniform luminance distribution. If necessary, a reflective polarizing film may be used together with the prism film 32, and only the reflective polarizing film may be used without the prism film 32. The protection film 33 positioned at the top protects the prism film 32 that is weak to scratches.

The reflecting plate 40 is positioned between the diffusion plate 31 and the light emitting diode circuit board 51. The reflecting plate 40 is provided with a light emitting diode receiving port 41 corresponding to the arrangement of the light emitting diodes 52. Each light emitting diode receiving port 41 has a light emitting diode group 53 composed of three light emitting diodes 52, and the light emitting diode receiving hole 41 may be formed somewhat larger than the light emitting diode group 53. have.

The reflector 40 serves to reflect light incident to the lower part and to supply the diffuser 31. The reflector 40 may be made of polyethylene terephthalate (PET) or polycarbonate (PC), and may be coated with silver or aluminum. In addition, the reflector 40 may be provided to be thicker so that no ions are generated by the strong heat generated from the light emitting diodes 52.

The light emitting diode circuit board 51 has a bar shape, and eight are arranged side by side at equal intervals. Since a large amount of heat is generated in the light emitting diode 52, the light emitting diode circuit board 51 may be made of aluminum having excellent heat transfer rate as a main material. Although not shown, to facilitate heat dissipation, the backlight unit 90 may further include a heat pipe, a heat dissipation fin, a cooling fan, and the like.

The light emitting diodes 52 are mounted on the light emitting diode circuit board 51 and are disposed over the entire rear surface of the liquid crystal display panel 20. The light emitting diode 52 forms a light emitting diode group 53 including three light emitting diodes 52 and is mounted on the light emitting diode circuit board 51. The light emitting diode group 53 is composed of one red light emitting diode 52a, one green light emitting diode 52b, and a blue light emitting diode 52c, which are arranged to form an equilateral triangle. It is.

The LED groups 53 are arranged at regular intervals on the LED circuit board 51. The LED groups 53 of adjacent LED circuit boards 51 are alternately arranged.

The LED group 53 includes three light emitting diodes 52 emitting different colors. The different colors produced by these three light emitting diodes 52 are mixed to produce white light. The light emitting diodes 52 and the reflecting plates 31 are spaced at predetermined intervals to form a space in which the light emitted from each light emitting diode 52 may be mixed. As a result, the backlight unit 90 may supply white light to the liquid crystal display panel 10.

However, the light emission characteristics of the light emitting diodes 52 may be changed due to a change in the external environment such as the temperature rise of the backlight unit 90 due to the driving of the liquid crystal display device 1, and thus white light may not be provided. In order to solve this problem, the present invention uses the optical sensor unit 70 to measure the color characteristics of the light provided from the light source unit 50. The optical sensor unit 70 is a device that detects wavelengths of light of different colors generated by the three light emitting diodes 52a, 52b, and 52c to supply uniform white light to the liquid crystal display panel 20.

2 and 3, the optical sensor unit 70 according to the present invention includes an optical sensor circuit board 71 and an optical sensor 72 mounted on the optical sensor circuit board 71. ; It includes a shielding case 73 having a light receiving hole 74 for exposing the light sensor 72, and a light receiving unit 75 for receiving the light generated by the light source unit (50).

The optical sensor circuit board 71 is provided with an optical sensor 72 that senses the wavelength of light, and a circuit pattern or electronic component for processing the sensed value and transmitting it to the light source controller 61. The shielding case 73 covers the optical sensor circuit board 71 and the optical sensor 72 so that the optical sensor 72 is exposed by the light receiving hole 74. The shielding case 73 includes a front case 73a covering a surface on which the optical sensor 72 is provided, and a rear case 73b covering the rear surface of the optical sensor circuit board 71. Although not illustrated, the front case 73a and the rear case 73b are coupled to each other by a bond, a hook, a screw, or the like. And, as shown in Figure 2, the optical sensor circuit board 71 is screwed into the inside of the front case (73a). Shielding case 73 serves to block the light that can be introduced from the side, such that the light sensor 72 is used in an optimal state. Here, the dimmed light refers to light generated outside the light source unit 50, such as light flowing from the gap between the upper cover and the lower cover. By providing the shielding case 73 as described above, the incident light directing characteristic of the light generated by the light source unit 50 is improved.

The optical sensor 72 detects the color characteristic of the light received by the light receiving unit 75 and transmits the color characteristic to the light source controller 61. The optical sensor 72 according to the present invention includes a red sensor 72a for detecting different light generated from the red light emitting diode 52a, the green light emitting diode 52b, and the blue light emitting diode 52c, and a green sensor ( 72b), blue sensor 72c. The light receiving unit 75 covers the optical sensor 72, and a part of the light receiving unit 75 is inserted into the light receiving hole 74 so that the other part is exposed to the outside. The light receiving portion 75 according to the present invention includes a support portion 76 accommodated in the light receiving hole 74 and an incidence portion 77 extending from the support portion 76 and exposed to the outside. The incident portion 77 according to the present invention has a lens shape convex toward the light source portion 50. In particular, the incidence part 77 set the curvature of the lens so that light may be collected without missing the light incident from the side surface in consideration of the refractive index of the lens. As a result, as shown in FIG. 3, not only the front surface of the optical sensor unit 70 but also light incident to the side surface may be effectively received and transmitted to the optical sensor 72. In addition, the light receiving unit 75 may accurately receive the blue, red, and green light generated by the current light source unit 50. Accordingly, the uniform white light can be optimally maintained by sensing the wavelength of light accurately received, comparing the sensed value with a reference value, and feeding back the difference value. That is, the incident light directing characteristic is improved by the light receiving unit 75, so that the sensitivity of the optical sensor 72 is improved, and thus the white balance can be optimally maintained.

The optical sensor unit 70 according to the present invention is located on the side wall 83 of the lower cover 80. The lower cover 80 according to the present invention includes a bottom portion 81 and sidewalls 83 extending upwardly from an edge of the bottom portion 81 to form an accommodation space for accommodating the backlight unit 90. Here, the bottom part 81 is a substantially rectangular shape having a long side and a short side, and the side wall 83 is the first and second side walls 83a and 83b extending from the long side edge, and the third and the third extending from the short side edge. Four side walls 83c and 83d. The light emitting diode circuit board 51 is arranged to be parallel to the long side.

The optical sensor unit 70 according to the present invention is preferably provided in the lower cover 80 in order to effectively receive the light from the light source unit 50. More specifically, it is preferable that the light receiving portion 75 is disposed on the inner wall of the first side wall 83a so that the light receiving portion 75 faces the light source portion 50 at the central portion of the first side wall 83a. In the embodiment of the present invention, one optical sensor unit 70 is provided to reduce manufacturing costs, but a plurality of optical sensor units 70 may be installed to more accurately control white light. The plurality of photosensors 70 may be located at a plurality of points on the sidewall 83 to receive light. In order to effectively receive the light from the light source unit 50, the plurality of light sensor units 70 may be provided on the side wall 83 rather than the bottom 81. The optical sensor unit 70 may be located on the third and fourth side walls 83c and 83d, but the first and second side walls are parallel to the arrangement direction of the LED group 53 in order to receive more accurate light. It is preferable to be provided in (83a, 83b).

As shown in FIG. 4, the value sensed by the optical sensor unit 70 is transferred to the light source controller 61, and the light source controller 61 compares and determines the sensed value and the reference value to determine the light source driver 65. ). The light source driver 65 supplies power to the light emitting diodes 52 through the light emitting diode circuit board 51. Preferably, the light source driver 65 may adjust the power supply of the light emitting diodes 52 according to light emission colors and positions. The light source controller 61 controls the light source driver 65 to adjust the power supplied to the light emitting diode 52 based on the color characteristics sensed by the photosensor 73. For example, when color characteristics are detected due to a lack of red light, the power supplied to the red light emitting diode 52a is increased, or the power supplied to the green light emitting diode 52b and the blue light emitting diode 52c is decreased.

Hereinafter, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, only features distinguishing from the first embodiment will be described and described, and descriptions thereof will be omitted or summarized according to the first embodiment and known techniques. In addition, for the convenience of description, the same components will be described with the same reference numerals.

The incident portion 77 of the light receiving portion 75 according to the second embodiment of the present invention does not have a uniform curved surface. That is, as shown in FIG. 5, the incident part 77 includes the first convex lens part 77a and the second convex lens corresponding to the red sensor 72a, the green sensor 72b, and the blue sensor 72c, respectively. A portion 77b and a third convex lens portion 77c are included. The structure of the incidence portion 77 is finely divided for each of the red sensor 72a, the green sensor 72b, and the blue sensor 72c, thereby improving the light condensing or light receiving efficiency of the red light, the green light, and the blue light. That is, since each sensor collects or receives light along red light, green light, and blue light, the sensitivity of the light sensor 72 is improved, so that uniform white light can be optimally maintained.

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.

As described above, according to the present invention, a backlight unit including an optical sensor unit having improved incident light directing characteristics and a display device including the same are provided.

Claims (17)

A display panel; A light source unit disposed on a rear surface of the display panel; An optical sensor unit detecting a color of light generated by the light source unit; A light source driving unit supplying power to the light source unit; And a light source controller controlling the light source driver to adjust the color of light generated by the light source based on the color sensed by the optical sensor. The optical sensor unit includes a light sensor, a light shielding hole for exposing the light sensor, a shielding case covering the optical sensor, and a light receiving unit positioned in the light receiving hole and receiving light from the light source unit. Device. The method of claim 1, Further comprising a lower cover having a bottom portion and a side wall to receive the light source portion, And the optical sensor unit on the sidewalls. The method of claim 2, The bottom portion is provided in a substantially rectangular shape having a long side and a short side, And the optical sensor unit is positioned at a central portion of at least one of sidewalls extending from the long side. The method of claim 2, The optical sensor unit further includes an optical sensor circuit board on which the optical sensor is mounted, And the shielding case further covers the optical sensor circuit board. The method of claim 3, And the light sensor part is positioned on an inner surface of the side wall such that the light receiving part faces the light source part. The method of claim 5, And the light receiving portion has a lens shape convex toward the light source portion. The method of claim 5, The optical sensor detects the colors of red light, green light and blue light, respectively, and includes a red sensor, a green sensor, and a blue sensor disposed adjacent to each other. The light receiving part includes a support part accommodated in the light receiving hole, and an incident part extending from the support part and exposed to the outside, And the incident part includes a first convex lens part, a second convex lens part, and a third convex lens part corresponding to the red sensor, the green sensor, and the blue sensor, respectively. The method of claim 1, The light source unit may include a green light emitting diode, a red light emitting diode, and a blue light emitting diode disposed adjacent to each other. The method of claim 8, And the light source controller controls the light source driver for each color of light emitted from the light source unit. The method of claim 2, The optical sensor unit is located at a plurality of points on the side wall as a plurality of light receiving parts, And the light source controller controls the light source driver by dividing the light source unit by zones. The method of claim 1, And the display panel comprises a liquid crystal display panel. A light source unit; An optical sensor unit detecting a color of light generated by the light source unit; A light source driving unit supplying power to the light source unit; And a light source controller controlling the light source driver to adjust the color of light generated by the light source based on the color sensed by the optical sensor. The light sensor unit includes a light sensor, a light receiving hole for exposing the light sensor, a shielding case covering the light sensor, and a light receiving unit positioned in the light receiving hole and receiving light from the light source unit. unit. The method of claim 12, The optical sensor unit, Further comprising an optical sensor circuit board on which the optical sensor is mounted, And the shielding case further covers the optical sensor circuit board. The method of claim 13, And the light sensor unit is arranged such that the light receiving unit faces the light source unit. The method of claim 14, The light receiving unit is a backlight unit, characterized in that the convex lens shape toward the light source. The method of claim 14, The optical sensor detects the colors of red light, green light and blue light, respectively, and includes a red sensor, a green sensor, and a blue sensor disposed adjacent to each other. The light receiving part includes a support part accommodated in the light receiving hole, and an incident part extending from the support part and exposed to the outside, And the incident part includes a first convex lens part, a second convex lens part, and a third convex lens part corresponding to the red sensor, the green sensor, and the blue sensor, respectively. The method of claim 12, And the light source unit comprises a green light emitting diode, a red light emitting diode, and a blue light emitting diode disposed adjacent to each other.

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