KR100677151B1 - Back light unit and liquid display apparatus employing it - Google Patents

Abstract

Disclosed are a backlight unit including a plurality of light emitting device units arranged on a base plate and varying an interval between arrangements such that an outer portion has a higher density than an intermediate portion, and a liquid crystal display device employing the same.

According to the disclosed backlight unit, a dark-looking part is not generated due to lack of light at the corner point, and the overall brightness uniformity is improved.

Description

Back light unit and liquid display apparatus employing it}

1 shows an arrangement of a general light emitting diode in a direct light emitting backlight unit using the light emitting diode as a point light source.

2 is a cross-sectional view schematically showing the structure of a backlight unit according to an embodiment of the present invention.

3 is a plan view schematically showing one embodiment of the arrangement of the light emitting device units in FIG.

4 is a plan view schematically showing another embodiment of the arrangement of the light emitting device unit in FIG. 2.

FIG. 5 is a plan view schematically showing another embodiment of the arrangement of the light emitting device unit in FIG. 2.

6 is an enlarged cross-sectional view of the light emitting device unit of FIG. 2.

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

8A shows the uniformity simulation results when the light emitting device units are arranged in a conventional arrangement method.

8B shows the uniformity simulation result when the light emitting device units are arranged in the arrangement method according to the present invention.

9 schematically shows an arrangement specification of a light emitting device unit for obtaining the results of FIGS. 8A and 8B.

10 schematically shows the measurement ranges and points used to calculate uniformity assessments and darkening results.

11 schematically shows a liquid crystal display device having a backlight unit according to the present invention.

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

10,50 ... light emitting device unit 11 ... light emitting diode chip

13 ... side emitter 60 ... dome collimator

101 ... Base plate 110 ... Reflective diffuser plate

120 ... reflective mirror 130 ... optical plate

140 ... Transmissive diffuser 150 ... Brightness enhancement film

170 ... Polarization Enhancement Film 300 ... Liquid Crystal Panel

The present invention relates to a backlight unit and a liquid crystal display device employing the same, and more particularly, to a direct light emitting backlight unit and a liquid crystal display device employing the same.

A liquid crystal display, which is one of flat panel displays, is a light-receiving display device that itself does not emit light to form an image, but light is incident from the outside to form an image. The backlight unit is installed on the back of the liquid crystal display to irradiate light.

The backlight unit has a direct light type for irradiating the liquid crystal panel with light from a plurality of light sources provided directly below the liquid crystal display, and sidewalls of a light guide panel (LGP) according to the arrangement of the light sources. It can be classified into an edge light type (edge light type) for transmitting the light from the light source installed in the liquid crystal panel.

A direct emitting type backlight unit may use a light emitting diode (LED) in which Lambertian light is emitted as a point light source.

In a direct light emitting backlight unit using a light emitting diode as a point light source, the light emitting diodes 5 are generally spaced at equal intervals p in a two-dimensional array on the printed circuit board 1, as shown in FIG. Are arranged.

However, when the light emitting diodes 5 are arranged at equal intervals as shown in FIG. 1, when measuring and observing the backlight unit from the front, there is a lack of light at the four corner points at each corner point of the backlight unit. Due to this, there is a problem that a dark part is found.

The present invention has been made to solve the above-mentioned problems, and the backlight is improved to improve the overall brightness uniformity by improving the arrangement of the light emitting device unit so that a dark-looking part does not occur due to lack of light at the corner point. It is an object of the present invention to provide a unit and a liquid crystal display device employing the same.

The backlight unit according to the present invention for achieving the above object, is arranged on the base plate, a plurality of light emitting device unit for varying the arrangement interval so that the outer portion has a higher density than the middle portion; characterized in that it comprises a.

According to an aspect of the present invention, the plurality of light emitting device units are arranged to form n lines on the base plate, and may be densely arranged at the end of the line on the at least one line from the outside relative to the center portion. have.

In this case, the distance between the light emitting device units arranged on at least one line from the outside is preferably gradually increased from the end portion to the center portion.

In addition, the same number of light emitting device units may be arranged in the n lines.

The light emitting device units may be arranged at equal intervals on the remaining lines of the n lines.

Here, when the arrangement interval of the light emitting device units arranged on the remaining line is d0, the minimum arrangement interval of the light emitting device unit at the end portion on the mall outer line is d1, and the maximum arrangement interval of the center portion thereof is d2. The light emitting device unit can be arranged such that the relationship of d1 <d0 <d2 is established.

According to another feature of the invention, the plurality of light emitting device units are arranged to form n lines on the base plate, and the number of light emitting device units arranged on at least one line from the outside is arranged in the remaining lines It may be arranged to be larger than the number of device units.

In this case, the light emitting device units may be arranged at equal intervals on the remaining lines of the n lines.

In addition, the distance between the light emitting device units arranged on at least one line from the outside may be arranged to gradually increase from the end portion to the center portion.

According to another feature of the invention, the plurality of light emitting device units are arranged to form n lines on the base plate, and the line-to-line spacing in the middle along the arrangement direction of the n lines is between lines in the middle. It can be arranged to be denser than the spacing.

In this case, the same number of light emitting device units may be arranged in the n lines.

On the other hand, the light emitting device unit includes a light emitting diode chip for generating light; And a collimator for collimating light incident from the light emitting diode chip.

The collimator may be a side emitter that allows the incident light to travel approximately laterally.

The collimator may be dome shaped.

A backlight unit according to the present invention includes an optical plate; And a plurality of reflection mirrors formed on one surface of the optical plate to reflect light emitted directly upward from the light emitting device unit.

The optical plate may be any one of a transparent PMMA and a second transparent diffusion plate.

At least one of a brightness enhancement film for improving the linearity of the light emitted from the first transmission diffusion plate and a polarization enhancement film for increasing the polarization efficiency may be further provided.

Light emitting device units emitting R, G, and B color light may be alternately arranged on the line.

The backlight unit according to the present invention may further include a first transmission diffusion plate positioned above the light emitting device unit to diffusely transmit incident light.

The display apparatus may further include a reflection diffuser plate positioned below the light emitting device unit to diffusely reflect incident light.

A liquid crystal display device according to the present invention for achieving the above object is a liquid crystal panel;

And a backlight unit having at least one of the above-described features for irradiating light to the liquid crystal panel.

Hereinafter, a preferred embodiment of a backlight unit and a liquid crystal display device employing the same according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view schematically showing the structure of a backlight unit according to an embodiment of the present invention.

Referring to FIG. 2, the backlight unit 100 according to the present invention includes a plurality of light emitting device units 10 disposed on the base plate 101. The backlight unit 100 may further include a transmission diffusion plate 140 positioned above the light emitting device unit 10 to diffusely transmit incident light. In addition, the backlight unit 100 may further include a reflective diffusion plate 110 positioned below the light emitting device unit 10 to diffusely reflect incident light.

Here, when the main traveling direction of the light emitted from the light emitting diode chip 11 (LED chip) of the light emitting device unit 10 is upward, the downward direction is the opposite direction. The main traveling direction of the light emitted from the light emitting diode chip 11 substantially corresponds to the central axis of the light emitting device unit 10.

The base plate 101 serves as a substrate for installing the plurality of light emitting device units 10. The base plate 101 may be a printed circuit board (PCB) in which the light emitting diode chip 11 of the light emitting device unit 10 is arranged to be electrically connected. Here, a printed circuit board (PCB) for driving the light emitting device unit 10 may be provided separately from the base plate 101.

The plurality of light emitting device units 10 are arranged in the base plate 101 with a variation in the arrangement interval such that the outer portion has a higher density than the middle portion.

FIG. 3 schematically shows one embodiment of the arrangement of the light emitting device unit 10 of FIG. 2.

Referring to FIG. 3, the light emitting device units 10 may be arranged in an array to form n lines on the base plate 101.

At this time, the light emitting device units 10 are arranged to form n lines L1 to Ln on the base plate 101, as shown in FIG. 3. The spacing between lines is wider than the spacing between light emitting device units 10 arranged on each line.

At this time, the light emitting device unit 10 is arranged on the at least outermost line, for example, L1 and Ln so as to be denser than the center portion at the end. The spacing of the arrangements of the light emitting device units 10 can be gradually changed, i.e., gradually increased from the ends of the outer lines L1 and Ln to the center portion. The light emitting device units 10 can be arranged at equal intervals on the intermediate lines L2 to Ln-1. At this time, the interval between the light emitting device units 10 disposed at the ends of the outer lines L1 and Ln is smaller than the interval between the light emitting device units 10 disposed on the intermediate lines L2 to Ln-1.

Preferably, the number of the light emitting device units 10 arranged in each line can be the same, and in this case, the arrangement interval of the light emitting device units 10 in the center portions of the outer lines L1 and Ln is an intermediate line. It becomes wider than the arrangement | positioning interval of the light emitting device unit 10 arrange | positioned at equal intervals on L2-Ln-1.

For example, the spacing of the light emitting device units 10 arranged at equal intervals on the intermediate lines L2 to Ln-1 is d0, the minimum arrangement spacing of the light emitting device units 10 at the ends of the outer lines L1 and Ln. When d1 and a maximum arrangement interval of the central portion thereof are d2, the light emitting device units 10 can be arranged such that a relationship d1 < d0 <

As described above, if the number of light emitting device units arranged on each line is the same and only the arrangement interval of the light emitting device units arranged on the outer line is changed, the same as when all the light emitting device units are arranged at equal intervals. Since a number of light emitting device units can be used, it is possible to improve the problem of dark areas where the four corner points appear dark without causing any increase in manufacturing cost, and improve the overall brightness uniformity.

In Fig. 3, the light emitting device unit 10 is arranged in five lines, and the outer first line L1 and the fifth line Ln are arranged so that the ends are more dense as described above, and the middle three Lines L2 to Ln-1 show examples of being arranged at equal intervals. The number of lines for arranging the light emitting device units 10 and the number of light emitting device units 10 arranged in each line may be variously modified according to design conditions.

When the light emitting device unit 10 is disposed as described above, the amount of light at the four corner portions of the backlight unit 100 can be increased as compared with the case where the light emitting device unit 10 is arranged at equal intervals. Even if the overall brightness uniformity can be improved, and the light amount is small in the four corners of the backlight unit 100 does not appear to be a problem.

Brightness uniformity of the backlight unit 100 is an important factor in evaluating the surface light source, and the brightness of the four corners is generally evaluated to be the lowest, so that the uniformity of the backlight unit tends to be lowered. However, according to the arrangement of the light emitting device unit 10 according to the exemplary embodiment of the present invention, since the light emitting device units 10 are arranged at narrow intervals in each of four corners, brightness uniformity may be improved and dark portions may be removed. .

Meanwhile, the arrangement of the plurality of light emitting device units 10 may be variously modified. 4 schematically shows another embodiment of the arrangement of the light emitting device unit 10 of FIG. 2. Substantially the total number of light emitting device units 10 arranged on each line is not as small as in FIG. 4, but may be larger as shown in FIG. 3. 4 and 5 to be described later, the number of light emitting device units 10 is reduced for convenience. 4 and 5 show an example in which the light emitting device units 10 are arranged to form six lines, the number of lines may be variously modified according to design conditions.

As shown in FIG. 4, the plurality of light emitting device units 10 are arranged to form n lines on the base plate 101, and are arranged on at least one line from the outside, for example, on the L1 and Ln lines. The number of units 10 may be arranged to be larger than the number of light emitting device units arranged in the remaining lines L2 to Ln-1.

In the present embodiment, in addition to the larger number of light emitting device units 10 disposed on the outer lines L1 and Ln than the remaining lines L2 to Ln-1, the light emitting device units 10 are connected to the lines L1 and Ln. It is preferably arranged to be denser than the central portion at the end of.

At this time, similarly to the case of FIG. 3, the light emitting device unit 10 may be arranged such that its spacing gradually increases from the ends of the outer lines L1 and Ln to the center portion. Further, the light emitting device units 10 may be arranged at equal intervals in the remaining lines L2 to Ln-1.

Even when the plurality of light emitting device units 10 are arranged as shown in FIG. 4, since the light emitting device units 10 are arranged to have a higher density than the middle portion at the outer portion, due to the lack of light amount at the corner point. The dark-looking part is eliminated and the overall brightness uniformity can be improved.

FIG. 5 schematically shows another embodiment of the arrangement of the light emitting device unit of FIG. 2.

As shown in FIG. 5, the plurality of light emitting device units 10 are arranged to form n lines on the base plate 101, and an interval between lines Y1 from the outside is arranged along the arrangement direction of the n lines. It may be arranged to be denser than the spacing Y between the lines in the middle.

At this time, the number and arrangement intervals of the light emitting device units 10 arranged on each line can be the same.

Even in this case, since the light emitting device unit 10 is disposed so as to have a higher density than the middle portion in the outer portion when viewed as a whole of the backlight unit 100, a dark-looking portion is not generated due to the lack of light amount at the corner point and overall brightness Uniformity can be improved.

FIG. 5 shows an example in which the light emitting device units 10 are disposed at equal intervals on each line. In addition to changing the distance between the lines as shown in FIG. 5, at least one of the light emitting device units 10 as shown in FIG. It is also possible to vary the spacing of the arrangement of the light emitting device units 10 on the outer lines to be more compact at the corners.

When the line direction is referred to as the horizontal direction and the direction in which the lines are arranged as the vertical direction, as shown in FIGS. 3 to 5, the arrangement intervals of the light emitting device units 10 are changed in the horizontal and / or vertical directions so that the backlight unit (100) Overall, when the plurality of light emitting device units 10 are disposed with a higher density of the light emitting device unit 10 in the outer part, in particular in the corner part, than in the middle part, the overall brightness uniformity can be greatly improved. . 3 and 5 correspond to an arrangement structure in which the amount of light is increased by reducing the distance between the light emitting device units 10 at four corners, thereby improving brightness and removing dark portions. 4 shows that the number of light emitting device units 10 is the same for each line, and the intervals of the light emitting device units 10 for each line are changed in the vertical direction.

Meanwhile, as illustrated in FIG. 6, the light emitting device unit 10 includes a light emitting diode chip 11 for generating light and a collimator for collimating light incident from the light emitting diode chip 11. And a side emitter 13 which allows the incident light to travel approximately in the lateral direction.

The light emitting diode chip 11 for generating light may be coupled to the side emitter 13 while being disposed on the base 12.

At this time, the light emitting diode chip 11 and the side emitter 13 is preferably in close contact. As such, by closely contacting the LED chip 11 and the side emitter 13, the amount of light generated in the LED chip 11 and entering the side emitter 13 may be maximized.

The light emitting device unit 10 may be provided to emit R, G, and B color light. In this case, a light emitting diode chip that generates R, G, or B color light is used as the light emitting diode chip 11 in the light emitting device unit 10. On each of the lines L1 to Ln, the light emitting device units 10 that emit R, G, and B color light may be alternately arranged.

In this case, the number of light emitting device units for each color light arranged on each line may vary in number in consideration of the amount of light emitted therefrom.

The amount of R, G, and B color light emitted from the R, G, and B light emitting diode chips may be different. Currently, the amount of light emitted from the G light emitting diode is smaller than that of other R and B light emitting diodes. Accordingly, in consideration of this, for example, the light emitting device units for R and B may be arranged in the same number on each line, and the G light emitting device units may be arranged to be twice that. The arrangement order of the light emitting device units for R, G, and B on each line may be, for example, R, G, G, B or B, G, G, R order.

Alternatively, the light emitting device units 10 may all be provided to emit white light. In this case, a light emitting diode chip in which all of the light emitting diode chips 11 generate white light is used in the light emitting device unit 10.

When using a light emitting diode chip for generating R, G, B color light or a light emitting diode chip for generating white light in the light emitting device unit 10 as described above, applying the backlight unit 100 according to the present invention The liquid crystal display device can display a color image.

Meanwhile, referring to FIG. 6, the side emitter 13 has a transparent body made of a transparent material. The side emitter 13 has, for example, a funnel-shaped reflecting surface 14 that is inclined with respect to the central axis C, and a central axis for refracting and transmitting the light reflected and incident on the reflecting surface 14. The first refractive surface 15 inclined with respect to (C) and the second refractive surface 157 having a convex shape connected from the bottom surface to the first refractive surface 15. Light emitted from the light emitting diode chip 11 and incident toward the reflecting surface 14 of the side emitter 13 is reflected by the reflecting surface 14 and directed to the first refractive surface 15, and the first refractive surface 15 Permeate through) and progress in the lateral direction. In addition, the light emitted from the light emitting diode chip 11 and incident on the convex second refractive surface 17 passes through the second refractive surface 17 and travels in a substantially lateral direction.

Here, the shape of the side emitter 13 may be variously modified in a range that emits light incident from the light emitting diode chip 11 in the lateral direction.

On the other hand, the reflective diffuser 110 diffuses and reflects the incident light to proceed upward. The reflective diffuser plate 110 is placed on the base plate 101 so that it can be located below the light emitting device unit 10. To this end, a plurality of holes through which the plurality of light emitting device units 10 may be formed are formed in the reflective diffuser plate 110, and the reflective diffuser plate 110 has a state where the light emitting device unit 10 is fitted in the hole. The furnace base plate 101 is installed.

The transmission diffusion plate 140 is positioned above the light emitting device unit 10 and the reflection diffusion plate 110 to be spaced apart from the lower portion 100a of the backlight unit 100 by a predetermined distance d. The transmission diffusion plate 140 diffuses and transmits incident light.

In this case, when the transmission diffusion plate 140 is too close to the light emitting device unit 10, the portion where the light emitting device unit 10 is positioned may be brighter than the rest of the light emitting device unit 10, and thus brightness uniformity may be reduced. In addition, as the transmission diffusion plate 140 is spaced apart from the light emitting device unit 10, the thickness of the backlight unit 100 increases. Therefore, the separation distance d between the transmission diffusion plate 140 and the lower portion 100a of the backlight unit 100 including the light emitting device unit 10 and the reflection diffusion plate 110 is determined by diffusion of light. It is desirable that the light be set to a minimum within a range that can be mixed as well as desired.

On the other hand, most of the light emitted from the light emitting diode chip 31 of the light emitting device unit 10 is emitted laterally by the side emitter 13, but there may be some light that passes upward through the side emitter 13 have. The amount of light traveling upwards of the side emitter 13 may be, for example, approximately 20% of the light emitted from the light emitting diode chip 31.

Due to the presence of light traveling above the side emitter 13, a light spot may be visible at the light emitting diode 31 chip position when viewed from above the backlight unit. In addition, for color implementation, for example, when arranging R, G, and B light emitting diode chips emitting color light of R, G, and B, color may be seen.

Accordingly, the backlight unit 100 according to the present invention includes a plurality of reflective mirrors 120 formed on one surface of the optical plate 130 to reflect the light emitted directly upward from the light emitting device unit 10 without directly traveling. It is preferable to further provide. In this case, the plurality of reflective mirrors 120 may be formed in an array on one surface of the optical plate 130 so as to correspond to the array of the light emitting device units 10 so as to exist above each light emitting device unit 10.

The optical plate 130 on which the plurality of reflection mirrors 120 are formed may be made of a transparent PMMA that transmits incident light as it is. In addition, the optical plate 130 may be formed of a transmission diffusion plate.

In this case, the plurality of reflective mirrors 120 and the light emitting device unit 10 may be spaced apart from each other by a predetermined interval, and the optical plate 130 may be supported by the support 135 so that the interval may be maintained. It is preferable. The support 135 supports the optical plate 130 with respect to the reflective diffuser plate 110 or the base plate 101.

In the case of using the transmission diffusion plate as the optical plate 130, since the light diffusion may occur more sufficiently than the case where only the reflection diffusion plate 110 and the transmission diffusion plate 140 are provided, the transmission diffusion plate 140. ) And the distance between the light emitting device unit 10, that is, the distance d between the transmission diffusion plate 140 and the lower part 100a of the backlight unit 100 according to the present invention, can be reduced. It can contribute to reducing the thickness of).

Of course, when using the transmission diffusion plate as the optical plate 130, the transmittance of light may be relatively lower than when using a transparent PMMA. Accordingly, the optical plate 130 may be determined depending on whether the transmission diffuser plate or the transparent PMMA is focused on increasing the light emission rate or the thickness of the backlight unit 100.

Meanwhile, the backlight unit 100 according to the present invention may further include a brightness enhancement film (BEF) 150 for improving the straightness of the light emitted from the transmission diffusion plate 140. In addition, the backlight unit 100 according to the present invention may further include a polarization enhancement film 170 for increasing polarization efficiency.

The brightness enhancement film 150 may improve the brightness by increasing the straightness of the light by refracting and condensing the light emitted from the transmission diffusion plate 140.

For example, the polarization enhancement film 170 transmits light of p-polarized light and reflects light of s-polarized light, so that most of the incident light is emitted as one polarized light, for example, p-polarized light.

In the liquid crystal display device to which the backlight unit 100 according to the present invention is applied, a liquid crystal panel is provided on the backlight unit 100. As is well known, a liquid crystal panel is incident on the liquid crystal layer of the liquid crystal panel by injecting light of one linearly polarized light and changing the direction of the liquid crystal director by electric field driving, thereby changing the image by the polarization change of the light passing through the liquid crystal layer. Information and the like will be displayed.

Therefore, as light incident on the liquid crystal panel becomes single polarized light, the light utilization efficiency can be improved. Therefore, when the polarization improving film 170 is provided in the backlight unit 100 as described above, the light efficiency can be improved.

When the backlight unit 100 as described above is applied to the liquid crystal display, the four corner portions are prevented from appearing dark, so that the brightness uniformity can be improved, and the dark portions of the corner portions can be improved. It is possible to implement a high quality image with a uniform brightness.

On the other hand, in the above, the backlight unit according to the present invention has been described and illustrated, for example, having a light emitting device unit 10 in which the side emitter 13 is formed as a collimator, the backlight unit according to the present invention is shown in FIG. It is also possible to have a light emitting device unit 50 in which a dome-type collimator 60 is formed as shown. Figure 7 shows another embodiment of the backlight unit 100 according to the present invention, in addition to having a light emitting device unit 50 in which a dome-type collimator 60 is formed, the remaining components in the previous embodiment Is substantially the same as Accordingly, members having substantially the same or similar functions are denoted by the same reference numerals as before, and repeated description thereof will be omitted.

In the following, when arranging the light emitting device unit as in the backlight unit 100 according to the present invention, the effect of improving the dark portion when arranging the light emitting device at the end of the outer line to be denser than at the center portion thereof will be described. see.

FIG. 8A shows the optical simulation results when the light emitting device units are arranged in a conventional manner, and FIG. 8B shows the optical simulation results when the light emitting device units are arranged in a manner of one embodiment of the present invention. .

8A and 8B show that the light emitting device units are arranged in five lines, and each of R, G, B light emitting device units is 19, 38 and 19 R, G, G, B or B, G for each line. This is the result obtained when 76 light emitting device units per line were arranged in the order of, G, R in the horizontal 960 mm range as shown in FIG. 9 and the spacing between the lines was 105 mm.

FIG. 8A corresponds to the case where the light emitting device units are arranged at equal intervals on each line, and FIG. 8B shows the light emitting device units more densely at the end and the gap toward the middle part on the first line and the last fifth line. The light emitting device units are arranged at a distance from each other and the light emitting device units are arranged at equal intervals on the second to fourth lines.

Comparing Figs. 8A and 8B with each other, in the case where the light emitting device unit is arranged so that the light emitting device unit is more dense at the end of the outer line as in the present invention, the brightness at the four corner portions is all light emission in a conventional manner. It can be seen that the device unit is brighter than when the device units are arranged at equal intervals. This can be seen immediately by comparing the part shown by A _conventional part of FIG. 8A with the part shown by B _invention of FIG. 8B.

Using these optical simulation results, the results of calculating the uniformity and darkening improvement effect, compared with the existing method and the present invention, the uniformity and darkening improvement is about 3% from 86% to 89%, and the darkening improvement is It can be seen that the improvement is about 19% from 76% to 95%.

In this case, the uniformity and darkening result are the results calculated for the measurement range and point shown in FIG. As shown in Fig. 10, the measuring point is the center ①, four points 339mm horizontally and 191mm vertically from the center ②, ③, ④, ⑤, four points of the corner portion 484mm horizontally and 261.5mm vertically from the center. ⑥, ⑦, ⑧, ⑨, and the measurement width of each point was 50 mm.

When the brightnesses measured at the measuring points ①, ②, ③, ④, ⑤, ⑥, ⑦, ⑧, and ⑨ are T1, T2, T3, T4, T5, T6, T7, T8, and T9, the uniformity is T2, The minimum of T3, T4, T5 is divided by T1, and the cancer improvement is the percentage of the minimum of T6, T7, T8, T9 divided by T1.

Here, the uniformity is measured about 10% inward from the boundary, and the ANSI standard, which is an international standard used to evaluate the uniformity, corresponds to the center of each part when dividing the whole into nine areas. ③, ④, and ⑤ correspond to this point.

As a result of calculating the degree of uniformity and the improvement of the dark part using the simulation results of FIGS. 8A and 8B, when the light emitting device unit is arranged as in the present invention, the dark part can be greatly improved while slightly improving the uniformity without loss of uniformity. .

11 schematically shows a liquid crystal display device having a backlight unit 100 according to the present invention.

Referring to FIG. 11, the liquid crystal display device includes a backlight unit 100 and a liquid crystal panel 300 provided on the backlight unit 100. The liquid crystal panel is connected to the driving circuit unit. Here, in the field of the liquid crystal display device, since the specific structure of the liquid crystal panel and the display operation by driving the circuit are widely known, a detailed description and illustration thereof will be omitted.

According to the backlight unit of the present invention as described above, the plurality of light emitting device units are arranged on the base plate with variations in the arrangement interval such that the outer portion has a higher density than the middle portion. Thereby, a dark-looking part does not occur due to lack of light amount at the corner point, and the overall brightness uniformity of the backlight unit can be improved.

Claims (30)

And a plurality of light emitting device units arranged on the base plate and varying the arrangement interval such that the outer portion has a higher density than the middle portion. The plurality of light emitting device units, Are arranged to form n lines on the base plate, And at least one line from the outside is densely arranged in relation to the center portion at the end of the line. delete The backlight unit of claim 1, wherein a distance between the light emitting device units disposed on at least one line from the outside is gradually increased from the end portion to the center portion. 2. The backlight unit of claim 1, wherein an equal number of light emitting device units are arranged in the n lines. The backlight unit of claim 1, wherein the light emitting device units are disposed at equal intervals in the remaining lines except at least one line from the outside of the n lines. The method of claim 5, wherein the arrangement interval of the light emitting device units arranged on the remaining line is d0, When the minimum arrangement interval of the light emitting device unit at the end on the mall outer line is d1, and the maximum arrangement interval of the center portion thereof is d2, And the light emitting device unit is arranged such that a relationship of d1 < d0 < d2 is established. And a plurality of light emitting device units arranged on the base plate and varying the arrangement interval such that the outer portion has a higher density than the middle portion. The plurality of light emitting device units, Are arranged to form n lines on the base plate, And the number of light emitting device units arranged on at least one line from the outside is greater than the number of light emitting device units arranged on the remaining lines. The backlight unit of claim 7, wherein the light emitting device units are disposed at equal intervals in the remaining lines except at least one line from the outside of the n lines. 8. The backlight unit according to claim 7, wherein the distance between the light emitting device units arranged on at least one line from the outside is gradually increased from the end portion to the center portion. And a plurality of light emitting device units arranged on the base plate and varying the arrangement interval such that the outer portion has a higher density than the middle portion. The plurality of light emitting device units, Are arranged to form n lines on the base plate, And the line-to-line spacing in the outside along the arrangement direction of the n lines is arranged to be denser than the line-to-line spacing in the middle. The backlight unit of claim 10, wherein the n number of light emitting device units is arranged in the n lines. The light emitting device unit of claim 1, wherein the light emitting device unit comprises: A light emitting diode chip for generating light; And a collimator for collimating light incident from the light emitting diode chip. 13. The backlight unit of claim 12, wherein the collimator is a side emitter that allows the incident light to travel in a lateral direction. The backlight unit of claim 12, wherein the collimator has a dome shape. 12. The apparatus of claim 1 or 3 to 11, further comprising: an optical plate; And a plurality of reflection mirrors formed on one surface of the optical plate to reflect light emitted directly upward from the light emitting device unit. The backlight unit of claim 15, wherein the optical plate is any one of a transparent PMMA and a second transparent diffusion plate. The method according to any one of claims 1 or 3 to 11, further comprising at least one of a brightness enhancement film for improving the linearity of the light emitted from the first transmission diffusion plate and a polarization enhancement film for enhancing the polarization efficiency. And a backlight unit. The backlight unit according to any one of claims 1 to 3, wherein light emitting device units emitting R, G, and B color light are alternately arranged on the line. The backlight unit of claim 1, further comprising: a first transmission diffusion plate positioned above the light emitting device unit and configured to diffusely transmit incident light. The backlight unit of claim 19, further comprising a reflection diffuser plate positioned below the light emitting device unit to diffusely reflect incident light. A liquid crystal panel; And a backlight unit according to any one of claims 1 and 3 to 11 irradiating light to the liquid crystal panel. 22. The liquid crystal display device according to claim 21, further comprising a first transmission diffusion plate positioned above the light emitting device unit to diffusely transmit incident light. The liquid crystal display device of claim 22, further comprising a reflection diffuser plate positioned below the light emitting device unit to diffusely reflect incident light. The method of claim 21, wherein the light emitting device unit, A light emitting diode chip for generating light; And a collimator for collimating light incident from the light emitting diode chip. 25. The backlight unit of claim 24, wherein the collimator is a side emitter that allows the incident light to travel approximately laterally. 25. The backlight unit of claim 24, wherein the collimator has a dome shape. 22. The apparatus of claim 21, further comprising: an optical plate; And a plurality of reflection mirrors formed on one surface of the optical plate to reflect light emitted directly upward from the light emitting device unit. The backlight unit of claim 27, wherein the optical plate is any one of a transparent PMMA and a second transparent diffusion plate. The backlight unit of claim 21, further comprising at least one of a brightness enhancing film for improving the linearity of light emitted from the first transparent diffusion plate, and a polarization improving film for increasing the polarization efficiency. 22. The backlight unit according to claim 21, wherein light emitting device units emitting R, G, and B color light are alternately arranged on the line.

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