KR20080047822A - Light source unit, back light assembly having the same and display apparatus having the same - Google Patents

Abstract

A light source unit, a backlight assembly having the same, and a display device having the same are provided to improve a color tone of a display device without a color filter. A light emitting chip(312) emits light. A chip support unit(311) has one surface on which the light emitting chip is disposed. A tilted lens(320) covers the light emitting chip, is in contact with one end of the one surface of the chip support unit, and has a slope face tilted over the one surface. The slope face is coated with a reflecting material. The slope face is tilted at 10 to 170 degrees over one surface. The light emitting chip is disposed between the center of the tilted lens and the slope face. A chip tilting unit includes the light emitting chip disposed on the surface tilted at 10 to 90 degrees over the one surface. The light emitting chip is tilted to face the slope face.

Description

LIGHT SOURCE UNIT, BACK LIGHT ASSEMBLY HAVING THE SAME AND DISPLAY APPARATUS HAVING THE SAME}

1 is an exploded perspective view illustrating a display device according to an exemplary embodiment of the present invention.

FIG. 2 is a plan view illustrating the backlight assembly of FIG. 1. FIG.

3 is a cross-sectional view taken along line II ′ of FIG. 2.

4 is a cross-sectional view illustrating another example of the inclined lens illustrated in FIG. 3.

FIG. 5 is a cross-sectional view illustrating still another embodiment of the inclined lens shown in FIG. 3.

6 is a cross-sectional view illustrating light distribution depending on a position of a light emitting chip in the inclined lens shown in FIG. 3.

7 is a cross-sectional view showing another embodiment of the light source unit shown in FIG. 3.

FIG. 8 is a graph illustrating a shape of light distribution from the light source unit of FIG. 3.

FIG. 9 is a graph illustrating a shape of light distribution from the light source unit of FIG. 7.

FIG. 10 is a cross-sectional view illustrating an arrangement relationship of tilt lenses of the light source units illustrated in FIG. 2.

<Description of the symbols for the main parts of the drawings>

200: driving substrate 300: light source unit

310: point light source 311: chip support

312: light emitting chip 314: chip tilt

320: inclined lens 322: inclined surface

322a: first inclined plane 322b: second inclined plane

400: backlight assembly 600: display device

LG: Light source group LB: Light source bar

The present invention relates to a light source unit, a backlight assembly having the same, and a display device having the same, and more particularly, to a light source unit suitable for sequential driving, a backlight assembly having the same, and a display device having the same.

In general, a liquid crystal display device is a flat panel display that displays an image by using the light transmittance of the liquid crystal. The liquid crystal display includes a display panel for displaying an image using light and a backlight assembly for supplying light to the display panel. In a liquid crystal display, a display panel including three color filters selectively transmits white light from a backlight assembly, thereby displaying a color image.

Since the color filter type liquid crystal display device forms display pixels using three adjacent color filters as one unit, the actual resolution is reduced to about one third, and the transmittance and color purity are degraded due to the use of the color filter. Has

On the other hand, a liquid crystal display device applied to a TV monitor or the like mainly uses a light emitting diode having low power consumption and excellent luminous efficiency as a light source of the backlight assembly. Accordingly, color filters of the liquid crystal display device can be removed using red, green, and blue light emitting diodes. That is, the liquid crystal display sequentially emits red light, green light, and blue light from the light emitting diode for a predetermined time, thereby realizing a desired color by using a visual afterimage effect.

The sequential driving type liquid crystal display device is driven by dividing a section of one frame into a plurality of fields in which light of different colors is sequentially emitted. However, light emitted from each field is mixed with light emitted from an adjacent field, and color mixing occurs, which causes a problem of deterioration of color reproduction of the liquid crystal display.

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a light source unit for improving color reproducibility in a sequential driving method.

Another object of the present invention is to provide a backlight assembly having the above-described light source unit.

Further, another object of the present invention is to provide a display device having the above-described light source unit.

In order to realize the above object of the present invention, a light source unit according to an embodiment includes a light emitting chip emitting light, a chip support part on which one surface of the light emitting chip is disposed, and the light emitting chip, and in contact with an end of the one surface. It includes an inclined lens having an inclined surface inclined with respect to one surface. In this case, the inclined surface may be coated with a reflective material.

In order to achieve the above object of the present invention, a backlight assembly according to an embodiment includes a driving substrate and a plurality of light source groups disposed on the driving substrate and having red, green, and blue light source units. Each of the red, green, and blue light source units has a light emitting chip that emits light, a chip support part on which one surface of the light emitting chip is disposed, and the light emitting chip, the inclined surface in contact with an end of the one surface and inclined with respect to the one surface. It includes an inclined lens. In this case, the light source groups are arranged in one direction, and the inclined surface is inclined toward the one direction.

In accordance with another aspect of the present invention, a display device includes a display panel and a backlight assembly displaying an image. The backlight assembly includes a driving substrate and a plurality of light source groups disposed on the driving substrate, the plurality of light source groups including red, green, and blue light source units, each of the red, green, and blue light source units emitting light; The light emitting chip includes a chip support disposed on one surface and an inclined lens covering the light emitting chip, the inclined lens having an inclined surface in contact with an end of the one surface and inclined with respect to the one surface.

According to such a light source unit, a backlight assembly having the same, and a display device having the same, as the light source unit includes an inclined lens, light can be emitted in one direction. This can be applied to a sequential driving backlight assembly to prevent color mixing and to further improve color reproducibility.

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

1 is an exploded perspective view illustrating a display device according to an exemplary embodiment of the present invention. FIG. 2 is a plan view illustrating the backlight assembly of FIG. 1. FIG.

1 and 2, the display device 600 includes a backlight assembly 400 and a display panel 500.

The backlight assembly 400 includes a light source group LG having the storage container 100, the driving substrate 200, and the light source units 300.

The storage container 100 includes a bottom portion 110 and side portions 120 extending from an edge of the bottom portion 110 to form a storage space. The driving substrate 200 and the light source unit 300 are accommodated in the accommodation space. The storage container 100 is made of, for example, a metal having excellent strength and low deformation.

The driving substrate 200 has a plate shape, and the light source units 300 are disposed above the driving substrate 200. The driving substrate 200 is electrically connected to an external power supply device (not shown) to supply power to the light source unit 300, and includes a signal wiring for supplying power. For example, the driving substrate 200 may be made of a metal material having high thermal conductivity in order to emit heat generated from the point light sources 310 to the outside.

For example, the backlight assembly 400 may include one driving substrate 200 corresponding to the size of the bottom 110. In contrast, the backlight assembly 400 may include a plurality of driving substrates 200 extending in the longitudinal direction of the bottom portion 110.

The light source groups LG are disposed on the driving substrate 200 to generate light. The light source groups LG include red, green and blue light source units R, G, and B. Looking at the shape of each light source unit 300 is disposed on the driving substrate 200, first, the red, green and blue light source units (R, G, B) are adjacent to each other to form independent light source groups (LG). In this case, the light source groups LG are spaced apart in a row on the driving substrate 200 to form a plurality of light source bars LB1,..., LBN.

For example, one light source group LG may include one red light source unit R, two green light source units G, and one blue light source unit B. As such, the plurality of light source units 300 forming one light source group LG may be arranged in a line on the driving substrate 200 or in a polygonal shape such as a rhombus.

The backlight assembly 400 sequentially emits red light, green light, and blue light in the light source bar LB unit formed of the light source groups LG.

Specifically, first, the light source groups LG of the first light source bar LB1 emit red light. Subsequently, after a predetermined time, when the light source groups LG of the second light source bar LB2 emit red light, the light source groups LG of the first light source bar LB1 emit green light. Subsequently, when the light source groups LG of the third light source bar LB3 emit red light, the light source groups LG of the second light source bar LB2 emit green light and the light source group of the first light source bar LB1. LGs emit blue light. As such, as each of the light source bars LB sequentially emits red light, green light, and blue light from the first light source bar LB1 to the N-th light source bar LBN, a desired color is obtained using visual afterimages. Can be implemented.

Each light source unit 300 includes a light emitting chip 312 emitting light and an inclined lens 320 covering the light emitting chip 312. The inclined lens 320 reflects light emitted from the light emitting chip 312 in one direction. As such, as each light source unit 300 emits light in one direction by the inclined lens 320, color mixing between the light source bars LB may be minimized. The detailed shape of the inclined lens 320 and the shape of light distribution from the light source units 300 will be described later.

The display panel 500 is disposed above the backlight assembly 400 and displays an image using light supplied from the backlight assembly 400. The display panel 500 includes a first substrate 510, a second substrate 520 corresponding to the first substrate 510, and a liquid crystal layer interposed between the first substrate 510 and the second substrate 520. And a driving circuit unit 540 for driving the first substrate 510.

The first substrate 510 is a transparent glass substrate in which a thin film transistor (hereinafter, referred to as TFT) as a switching element is formed in a matrix form. A data line is connected to a source terminal of the TFTs, and a gate line is connected to a gate terminal. In addition, a pixel electrode made of a transparent conductive material is connected to the drain terminal.

The second substrate 510 is disposed to be spaced apart from the first substrate 510 by a predetermined interval. A common electrode made of a transparent conductive material is formed on the second substrate 520 to face the pixel electrode.

The liquid crystal layer of the liquid crystal layer is changed by an electric field formed by voltages applied to the first substrate 510 and the second substrate 520. The transmittance of light supplied from the backlight assembly 400 may be adjusted according to the arrangement change of the liquid crystal.

The driving circuit unit 540 includes a data printed circuit board 548 for supplying a data driving signal to the display panel 500, a gate printed circuit board 544 for supplying a gate driving signal to the display panel 500, and a data printed circuit board. The data driving circuit film 546 connects 548 to the display panel 500, and the gate driving circuit film 542 connects the gate printed circuit board 544 to the display panel 500.

In this case, as the backlight assembly 400 includes the light source units 300 sequentially generating light of different colors, the display panel 500 does not include a color filter for realizing color. That is, the display device 600 is driven by dividing one frame into a plurality of fields, and the display panel 500 adjusts the light transmittance by changing the response speed of the liquid crystal corresponding to each field, and adjusts the light transmittance of the backlight assembly 400. The light source units 300 sequentially generate light of different colors corresponding to each field. As a result, the display device 600 may implement a desired color without a color filter.

3 is a cross-sectional view taken along line II ′ of FIG. 2. 4 is a cross-sectional view illustrating another example of the inclined lens illustrated in FIG. 3. FIG. 5 is a cross-sectional view illustrating still another embodiment of the inclined lens shown in FIG. 3.

Referring to FIG. 3, each light source unit 300 includes a point light source 310 and an inclined lens 320.

The point light source 310 emits light and includes a chip support 311, a light emitting chip 312, and a power supply terminal 313.

The chip support 311 forms a body of the point light source 310. The chip support 311 is disposed on the driving substrate 200, and the light emitting chip 312 is disposed on an upper surface of the chip support 311.

The light emitting chip 312 generates monochromatic light such as red light, green light, blue light, and white light. The light emitting chip 312 is, for example, a P-N junction diode and is disposed on an upper surface of the chip support 311. For example, the light emitting chip 312 is supplied with a driving voltage transferred through a power supply terminal by a bonding wire (not shown).

The power supply terminal 313 extends outside the chip support 311 and is electrically connected to the driving substrate 200. A pair of power terminals 313 are electrically connected to the positive electrode and the negative electrode of the light emitting chip 312, respectively.

2 and 3, the point light sources 310 forming the respective light source units 300 have the same structure as above. At this time, the red light source unit R includes a red light emitting chip emitting red light, the green light source unit G includes a green light emitting chip emitting green light, and the blue light source unit B emits blue light. It includes a light emitting chip. Examples of the semiconductor material used for the light emitting chip 312 include GaP, GaAS, GaASP, AlGalnP, lnN, GaN, and the like, and the point light source 310 may emit visible light having various wavelengths according to the semiconductor material.

The inclined lens 320 is disposed above the point light source 310 to cover the point light source 310. The inclined lens 320 is made of a light transmissive material that can transmit light. For example, the inclination lens 320 may be made of a material such as polymethyl methacrylate (PMMA) or polycarbonate (PC) having a refractive index greater than that of air.

 The inclined lens 320 has an inclined surface 322 that is inclined with respect to an image side surface of the chip support 311. Accordingly, the inclined lens 320 emits light emitted from the light emitting chip 312 in one direction. In detail, the inclined lens 320 includes an inclined surface 322 in one direction and a spherical surface in the other direction opposite to the one side, based on the inner center O of the inclined lens 320.

The inclined surface 322 reflects light emitted from the light emitting chip 312. The inclined surface 322 is a plane inclined while contacting an end of one surface of the chip support 311. In one example, the inclined surface 322 may be coated with a reflector to reflect light.

Light emitted from the light emitting chip 312 is emitted to the display panel 500 through the inclined lens 320. At this time, the light emitting chip 312 emits light at a predetermined angle with respect to the upper straight direction. The first light L1 emitted from the light emitting chip 312 in the spherical direction is emitted directly through the spherical surface. In contrast, the second light L2 emitted from the light emitting chip 312 toward the inclined surface 322 is reflected by the inclined surface 322 and is emitted in the spherical direction. As such, the inclined lens 320 may emit light emitted from the light emitting chip 312 by the inclined surface 322 in one direction.

The inclined surface 322 may be inclined at an angle θ1 of about 10 to 170 degrees with respect to one surface. For example, when the inclined surface 322 is perpendicular to one surface, the inclined lens 320 may have a quarter hemisphere shape. In this case, when the inclined surface 322 and one surface form an acute angle, the amount of light reflected from the inclined surface 322 is increased more than when the inclined surface 322 and one surface form an obtuse angle. Accordingly, the light source unit 300 can further improve the light emission rate in one direction.

2 and 3, as the light source bars LB including the light source units 300 sequentially emit light of different colors, colors between the color lights emitted from the respective light source bars LB. Mixing may occur. Accordingly, in the present invention, the inclined lens 320 is formed on the upper side of the point light sources 310 to emit light in one direction, thereby preventing color mixing in the backlight assembly 400.

6 is a cross-sectional view illustrating light distribution depending on a position of a light emitting chip in the inclined lens shown in FIG. 3.

3 and 6, the inclined lens 320 covers the light emitting chip 312 to emit light emitted from the light emitting chip 312 in one direction. At this time, the shape of the light distribution varies according to the distance between the light emitting chip 312 and the inclined surface 322.

For example, when the light emitting chip 312 is disposed at the center of the inclined lens 320 (A), only the light L3 emitted in the direction of the inclined surface 322 of the light emitted from the light emitting chip 312 is inclined ( 322 is reflected.

On the contrary, the case where the light emitting chip 312 is disposed between the center of the inclined lens 320 and the inclined surface 322 will be described. Accordingly, the inclined surface 322 is disposed above the center of the light emitting chip 312. For example, the radius R of the bottom surface of the inclined lens 320 is about 3 mm, and the light emitting chip 312 may be disposed at a point about 2 mm (1) away from the center of the inclined lens 320 toward the inclined surface 322. have.

In this case, not only the light L6 emitted in the direction of the inclined plane 322 among the light emitted from the light emitting chip 312, but also the straight light L7 and the light L8 emitted in the spherical direction by the inclined plane 322. Reflected. That is, most of the light emitted from the light emitting chip 312 is reflected by the inclined surface 322 to be emitted in one direction, thereby forming an elliptical light having a long length. For example, the light distribution form emitted from the light source unit 300 may be an elongated cylindrical form.

As such, as the light emitting chip 312 is disposed closer to the inclined surface 322, the amount of light emitted in one direction increases. Accordingly, the light distribution form emitted from the light source unit 300 may be formed into a longer oval.

7 is a cross-sectional view showing another embodiment of the light source unit shown in FIG. 3. FIG. 8 is a graph illustrating a shape of light distribution from the light source unit of FIG. 3. FIG. 9 is a graph illustrating a shape of light distribution from the light source unit of FIG. 7.

For reference, FIGS. 6 and 7 are simulation results showing a light distribution form emitted from the light source unit 300 using an Advanced System Analysis Program (ASAP).

3 and 7, the light source unit 300 includes a point light source 310 and an inclined lens 320. The point light source 310 includes a chip support 311, a light emitting chip 312, a power supply terminal 313, and a chip tilting part 314. The point light source 310 of the present embodiment has the same configuration as the point light source 310 of the above-described embodiment except for the chip inclination part 314, and thus duplicated description thereof will be omitted. The same reference numerals and names are used. At this time, the inclined lens 320 has an inclined surface 322 inclined at a predetermined angle θ1 with respect to one surface of the chip tooth 311.

The chip inclined portion 314 is formed on one surface of the chip support 311 to support the light emitting chip 312. The upper surface of the chip inclined portion 314 may be an inclined surface 322 inclined at a predetermined angle θ2 with respect to one surface. Accordingly, the light emitting chip 312 may be disposed at a predetermined angle θ2, for example, about 10 to 90 degrees with respect to one surface by the chip tilting part 314. As such, as the light emitting chip 312 is inclined with respect to one surface, the light emitted from the light source unit 300 has a light distribution having a long elliptical shape.

For example, referring to FIG. 8, when the inclined surface 322 of the inclined lens 320 inclines about 45 degrees (θ1) with respect to one surface, and the inclination angle (θ2) of the light emitting chip 312 is 0 degrees, the light source The light distribution emitted from the unit 300 has an elliptical light shape close to a circle. In one example, the light distribution in this case may be in the form of an elliptical light having a short axis of about 84 mm and a long axis of about 94 mm.

In contrast, referring to FIG. 9, the inclined surface 322 of the inclined lens 320 is inclined about 45 degrees (θ1) with respect to one surface as in the above case, and the inclination angle (θ2) of the light emitting chip 312 is about. In the case of 45 degrees, the light distribution emitted from the light source unit 300 has a long elliptical light form. In one example, the light distribution in this case may be in the form of an elongated elliptical light having a short axis of about 92 mm and a long axis of about 123 mm.

As a result, when the light emitting chip 312 disposed on one surface is covered with the inclined lens 320, the light emitting unit 312 and the inclined surface 322 are inclined with respect to one surface as a reference, so that the light source unit is inclined. The emitted light from 300 may have a longer elliptical shape in one direction.

FIG. 10 is a cross-sectional view illustrating an arrangement relationship of tilt lenses of the light source units illustrated in FIG. 2.

2, 3, and 10, the light source groups LG including the light source units 300 are arranged in one direction on the driving substrate 200. Specifically, the light source groups LG are arranged in one direction to form a plurality of light source bars LB1, LB2, LB3, ..., LBN. That is, the one direction corresponds to the length direction of the light source bars LBN. Here, one light source group LG includes a red light source unit R, a green light source unit G, and a blue light source unit B to sequentially emit red light, green light, and blue light.

Each point light source 310 is covered with an inclined lens 320 having an inclined surface 322. The inclined surface 322 of the inclined lens 320 is inclined in one direction, that is, in the longitudinal direction of the light source bars LB. Thus, the light emitted through the inclined lens 320 may have a long elliptical shape in the longitudinal direction of the light source bars LB. Accordingly, the phenomenon of mixing light of different colors emitted from adjacent light source bars LB in the backlight assembly 400 may be prevented, thereby improving color reproducibility of the display device 600.

Meanwhile, each light source bar LBN may include a plurality of light source groups LG. In the sequential driving backlight assembly 400, the light source groups LG which form one light source bar LBN emit the same color light at the same time. For example, the light source bar LBN may include first and second groups LG1 and LG2 disposed adjacent to each other. That is, the first and second groups LG1 and LG2 simultaneously emit red light, green light, and blue light.

The first group LG1 includes a first red light source unit R1, a first green light source unit G1, and a first blue light source unit B1 arranged in sequence, and the second group LG2 is in order. The second blue light source unit B2, the second green light source unit G2, and the second red light source unit R2 are disposed. That is, the first blue light source unit B1 of the first group LG1 and the second blue light source unit B2 of the second group LG2 are disposed adjacent to each other.

In this case, the first inclined surface 322a of the inclined lens 320 of the first group LG1 and the second inclined surface 322b of the inclined lens 320 of the second group LG2 may be inclined in a crossing direction. . That is, when the first inclined plane 322a covering the first red, green, and blue light source units R1, G1, and B1 of the first groups LG1 is inclined to the left, the second of the second groups LG2 may be inclined. The second inclined surface 322b covering the red, green, and blue light source units R2, G2, and B2 is inclined to the right.

As such, the inclined surfaces 322 of the inclined lenses 320 of the adjacent light source groups LG are inclined alternately with each other, thereby preventing the light emitted from the optical units 300 from being deflected in one direction, that is, left or right. In addition, the degree of integration of the same color light can be improved.

As described above, the light emitting chip used in the backlight assembly of the sequential driving method may be covered with an inclined lens to emit light emitted from the light emitting chip in one direction. Accordingly, color interference and color mixing between light emitted from sequentially driven light emitting chips can be minimized. Also, by applying such a backlight assembly, the color reproducibility of the display device from which the color filter is removed can be minimized. Can be improved.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

Claims (10)

Light emitting chip for emitting light; A chip support part on which the light emitting chip is disposed; And And an inclined lens covering the light emitting chip and having an inclined surface in contact with an end of the one surface and inclined with respect to the one surface. The light source unit of claim 1, wherein the inclined surface is coated with a reflective material. The light source unit of claim 1, wherein the inclined surface is inclined by 10 to 170 degrees with respect to the one surface. The light source unit of claim 1, wherein the light emitting chip is disposed between the center of the inclined lens and the inclined surface. The light source unit of claim 1, further comprising a chip inclination part in which the light emitting chip is disposed on a surface inclined by 10 to 90 degrees with respect to the one surface. The light source unit of claim 5, wherein the light emitting chip is inclined to face the inclined surface. A driving substrate; And A plurality of light source groups disposed on the driving substrate and having red, green and blue light source units; Each of the red, green and blue light source units Light emitting chip for emitting light; A chip support part on which the light emitting chip is disposed; And And an inclined lens covering the light emitting chip and having an inclined surface in contact with an end of the one surface and inclined with respect to the one surface. The backlight assembly of claim 7, wherein the light source groups are arranged in one direction, and the inclined surface is inclined toward the one direction. The method of claim 8, wherein when the light source groups adjacent to each other among the light source groups are referred to as a first group and a second group, And the inclined surfaces of the inclined lenses of the first group and the inclined surfaces of the inclined lenses of the second group are inclined in a staggered direction. A display panel displaying an image; And A backlight assembly having a drive substrate and a plurality of light source groups disposed on the drive substrate and composed of red, green and blue light source units, Each of the red, green and blue light source units Light emitting chip for emitting light; A chip support part on which the light emitting chip is disposed; And And an inclined lens covering the light emitting chip and having an inclined surface in contact with an end of the one surface and inclined with respect to the one surface.

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