JP2009105070A - Backlight unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a backlight unit capable of miniaturizing and slimming and capable of making subsequent processes such as rework processes easy. <P>SOLUTION: The backlight unit includes a plurality of LEDs 110 generating light and a plurality of LED modules 120 having printed circuit boards supporting and driving the plurality of LEDs 110. The plurality of LED modules 120 includes the plurality of LEDs 110 arrayed in a matrix shape with at least two of rows and columns, those 110 are divided into a plurality of blocks. Each block is separated in a circuit way with a printed circuit pattern to enable to switch on/off for every block. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a backlight unit, and more specifically, in a backlight unit using a light-emitting diode (LED) module, the backlight unit is slimmed, and an optical sheet required due to a defective LED module or The present invention relates to a backlight unit that can facilitate a reworking process of a reflection sheet.

  Recently, along with the technological development of the semiconductor industry, which has repeated rapid development, products having more powerful performance in addition to being smaller and lighter have been produced. CRT (cathode ray tube) widely used in information display devices up to now has many advantages in terms of performance and price, but has disadvantages in terms of downsizing or carrying. A liquid crystal display device has been proposed as one method for overcoming such disadvantages. Liquid crystal display devices have advantages such as small size, light weight, and low power consumption, and are attracting more and more attention as an alternative means that can overcome the shortcomings of CRT. The reality is that it is attached to information processing equipment.

  A liquid crystal display device applies a voltage to a specific molecular arrangement of liquid crystal to convert it to another molecular arrangement, and the liquid crystal cell that emits light by the molecular arrangement has a birefringence, optical rotation, dichroism, light scattering characteristics, etc. This is a display device that converts a change in optical properties into a change in viewing angle and uses light modulation by a liquid crystal cell.

  Since such a liquid crystal display device is a light receiving element that cannot emit light uniquely, the liquid crystal panel is illuminated using a backlight attached to the rear surface of the liquid crystal panel. The light transmittance of the liquid crystal panel is adjusted by an applied electric signal, and a still image or a moving image is expressed on the liquid crystal panel accordingly.

  As described above, in the backlight unit for supplying light to the liquid crystal panel, a cold cathode fluorescent lamp (CCFL) has been widely used, but recently, a portable device or a field sequential color ( The need for backlight units using light emitting diodes (hereinafter referred to as LEDs) has increased with the advent of various types of display devices and improved driving methods such as liquid crystal display devices. is doing.

  Hereinafter, a backlight unit using a light emitting diode will be described in detail with reference to FIG. FIG. 1 is a perspective view schematically showing a structure of a backlight unit according to the prior art.

  As shown in FIG. 1, the conventional backlight unit is located under a display panel (not shown) and includes a plurality of LEDs 110 that generate light and a plurality of printed circuit boards that support and drive the plurality of LEDs 110. The LED module 120 includes an optical sheet 140 that is spaced above the plurality of LED modules 120 with a predetermined gap, and a heat dissipation pad 130 provided on the back surface of the LED module 120.

  However, in the above-described conventional backlight unit, the optical sheet 140 provided on the upper side of the plurality of LED modules 120 is separated from the plurality of LED modules 120 with a predetermined gap therebetween. A single sheet is provided so as to cover all the plurality of LED modules 120. Here, the heat dissipating pads 130 on the lower surface of the LED module 120 are separated into the number of the LED modules 120 and are individually attached to the LED modules 120, or one heat dissipating pad 130 covers the entire LED module 120. Produced.

  However, as described above, when the optical sheet of the backlight unit is provided apart from the plurality of LED modules positioned at a lower distance with a predetermined gap, the display unit using the backlight unit is separated due to the separation distance. There is an inconvenience that miniaturization and slimming are difficult.

  In addition, when one of the optical sheets for controlling the light directivity is covered and fixed as a whole and the upper side of the plurality of LED modules is fixed as a whole, if one of the LED modules is damaged, the optical sheet fixed on the upper side of the optical module as a whole There is an inconvenience that the rework process of the backlight unit becomes complicated, such as having to be removed.

  The present invention has been made in view of the above problems, and includes an LED module, an optical sheet or a reflective sheet positioned above the LED module, and a heat dissipation pad positioned below the LED module. An object of the present invention is to provide a backlight unit that is provided in an integrated type and can reduce the size and slimness of the backlight unit and facilitate subsequent processes such as a rework process.

  In order to achieve the above object, a backlight unit according to the present invention includes a plurality of LEDs that generate light, and a plurality of LED modules having a printed circuit board that supports and drives the plurality of LEDs. The LED module includes a plurality of LEDs arranged in a matrix of two or more rows and two or more columns, and the plurality of LEDs are divided into a plurality of blocks so that each block can be turned on / off. Each block is separated in a circuit by a printed circuit pattern.

  The LED module may have 6 to 12 modules for the LED backlight unit size of 40, 46, and 52 types, and 6 to 20 for the 57 type. The LED module has a LED backlight unit size of 40 type, the number of modules is 6 to 12, the number of blocks per module is 4 to 14, and the number of LEDs per block is The number is 6-24.

  Alternatively, in the LED module, when the size of the LED backlight unit is 46 type, the number of the modules is 6 to 12, the number of blocks per module is 5 to 15, and the number of LEDs per block is The number is 6-24. The LED module has a size of the LED backlight unit of 52 type, the number of modules is 6-12, the number of blocks per module is 6-28, The number of LEDs is 6 to 24.

  In addition, the LED module has a size of 57 type LED backlight unit, the number of modules is 6 to 20, the number of blocks per module is 6 to 28, The number of LEDs is 6 to 24.

  In addition, the LEDs in each block included in the plurality of blocks can be connected in series. The plurality of LEDs may include a blue LED, a green LED, and a red LED. Further, the plurality of LEDs can emit white light. The white light may include a red phosphor and a green phosphor in a blue LED. The green phosphor may include any one of a silicate system, a sulfide system, and a nitride system.

  In order to achieve the above object, a backlight unit according to the present invention includes a plurality of LEDs that generate light, and a plurality of LED modules having a printed circuit board that supports and drives the plurality of LEDs. The LED module includes a plurality of white LEDs arranged in a matrix of two or more rows and two or more columns, and the white LED includes a red phosphor and a green phosphor in a blue LED, and the red fluorescence The color coordinates of the red light emitted by the body have four vertices (0.6448, 0.4544), (0.8079, 0.2920), (0.6427, 0.2905) based on the CIE 1931 color coordinate system, The color coordinates of the green light emitted by the green phosphor in the region surrounded by (0.4794, 0.4633) are four vertices (0.1 based on the CIE1931 color coordinate system). 70, 0.8037), (0.4117, 0.5861), (0.4197, 0.5316), and (0.2555, 0.5030). .

  In addition, the plurality of LEDs include an LED unit formed by a combination of arbitrary LEDs arranged at the shortest distance from each other, and the central light amount of the previous LED unit is 80% to 120% with respect to the average value of the light amount emitted from each LED. %.

  The plurality of LEDs are continuously arranged in a triangular shape, and the distance between the first LED and the second LED adjacent to each other arranged in the same row is 20 to 140 mm. The plurality of LEDs are continuously arranged in a triangular shape, and a column direction distance or a row direction distance between adjacent LEDs in the row and the column is 8.2 to 70 mm. Can do.

  The plurality of LEDs may have a rectangular shape and are continuously arranged, and a distance between adjacent LEDs may be 8.2 to 70 mm.

  In addition, the plurality of LEDs may be continuously arranged in a quadrangular shape, and an angle of the position where the LEDs are disposed with respect to the direction of the array of the LEDs may be 70 to 110 degrees. .

  In addition, the plurality of LED modules can be divided into a large number of blocks, and each block can be separated by a printed circuit pattern so as to be turned on / off for each block. The plurality of LED modules can be divided into a large number of blocks, and each block is separated by a printed circuit pattern so that each block can be turned on / off. The LEDs in each block are connected in series. Connected to.

  The red phosphor may include a nitride-based or sulfide-based red phosphor. The green phosphor may include any one of a silicate system, a sulfide system, and a nitride system.

  In order to achieve the above object, a backlight unit according to the present invention includes a plurality of LEDs that generate white light, and a plurality of LED modules that include a printed circuit board that supports and drives the plurality of LEDs. The LED modules can be divided into a large number of blocks, and each block is separated by a printed circuit pattern so that each block can be turned on / off, and the plurality of LED modules surround a certain central area. Can be arranged.

  Further, the LEDs provided in each block in the multiple blocks are connected in series. The distance between adjacent LEDs among the plurality of LEDs may be 8.2 to 70 mm.

  The white light may include a red phosphor and a green phosphor in a blue LED. The red phosphor may include a nitride-based or sulfide-based red phosphor. The green phosphor may include any one of a silicate system, a sulfide system, and a nitride system.

  According to the present invention, the upper optical sheet or reflection sheet sandwiching the LED module and the lower heat dissipating pad are integrally provided, and the backlight unit can be reduced in size and slim.

  According to the present invention, since the optical sheet or the reflection sheet is individually attached to the upper side of each LED module, if any one of the plurality of LED modules is damaged, the damaged LED module Only the optical sheet or the reflection sheet attached on the upper side can be selectively removed to facilitate subsequent processes such as a rework process.

  Also, from the viewpoint of color uniformity and brightness, by setting the number of LED modules, the number of blocks per module, and the number of LEDs per block according to the area of the backlight unit, the optical sheet or the reflective sheet It is possible to design with the number minimized.

  Thus, according to the present invention, the backlight unit can be reduced in size and slim, and the manufacturing yield of the backlight unit can be further improved.

It is the perspective view which showed schematically the structure of the backlight unit by a prior art. 1 is a perspective view schematically showing a structure of a backlight unit according to an embodiment of the present invention. It is a perspective view which shows the some arrangement | sequence form of the backlight unit by the 1st Embodiment of this invention. It is a top view which shows the some block form of the backlight unit by the 2nd Embodiment of this invention. It is a top view which shows the form which several LED of the backlight unit by the 2nd Embodiment of this invention appears. It is a top view which shows the some block form of the backlight unit by the 3rd Embodiment of this invention. It is a top view which shows the form with which several LED of the backlight unit by the 3rd Embodiment of this invention appears. 3 is a photograph showing the luminance of a backlight unit according to an embodiment of the present invention. It is a top view which shows the backlight unit by embodiment of this invention. FIG. 4 is a circuit diagram for split driving of a backlight unit according to an embodiment of the present invention. It is a perspective view which shows the LED module which has the other arrangement | sequence form of the backlight unit by embodiment of this invention.

  Further objects of the present invention and advantages obtained by the present invention will become more apparent from the embodiments described below with reference to the drawings.

  In the drawings, the thickness is shown enlarged to clearly show some layers and regions. Further, the same portions are denoted by the same reference numerals throughout the specification. Hereinafter, a backlight unit according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  First, a backlight unit according to an embodiment of the present invention will be described in detail with reference to FIG. FIG. 2 is a perspective view schematically showing the structure of the backlight unit according to the embodiment of the present invention.

  As shown in the figure, the backlight unit 100 according to the present invention is located under a display device (not shown) and includes a plurality of LEDs 110 that generate light and a plurality of printed circuit boards that support and drive the plurality of LEDs 110. The LED module 120 includes an optical sheet 140 attached to the upper side of the plurality of LED modules 120, and a heat dissipation pad 130 attached to the back surface of the plurality of LED modules 120.

  The plurality of LEDs 110 can emit white light. For example, the plurality of LEDs 110 may include a blue LED chip, and a red phosphor and a green phosphor disposed on the blue LED chip. Alternatively, the plurality of LEDs 110 may include a blue LED chip, a red LED chip, and a green LED chip. Here, the blue LED chip includes an LED chip having an emission wavelength of 250 to 420 nm and a blue phosphor disposed on the LED chip. Similarly, the red LED chip and the green LED chip each include a red phosphor and a green phosphor disposed on an LED chip having an emission wavelength of 250 to 420 nm.

Here, examples of the material used as the red phosphor include nitride-based composition CaAlSiN ₃ : Eu, sulfide-based composition (Ca, Sr) S: Eu, and the like.

Examples of the material used as the green phosphor include silicate-based A ₂ SiO ₄ with 2,1,4 composition, silicate-based A ₃ SiO ₅ with 3,1,5 composition, and SrGa ₂ S with sulfide composition. ₄ : Eu, nitride-based Beta-SiAlON, and the like. Here, as the phosphor having the silicate-based 2,1,4-based composition, a phosphor of (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu, X can be used. At this time, the Sr is an essential component, and Ba, Ca, and Mg can be selectively included as necessary (0 ≦ Ba, Ca, Mg ≦ 1). The Eu is used as an activator, and +2 valent Eu2 + is used. The X may contain at least one of Ho, Er, Ce, YF, Cl, Br, I, P, S, N, or Gd as an additive, and is selectively selected from the range of 1 PPM to 500,000 PPM. It can be used by adjusting the dope amount. Moreover, the phosphor of the silicate type 3, 1, 5 composition may be a phosphor of (Sr, Ba, Ca, Mg) ₃ SiO ₅ : Eu, X. Here, the Sr is an essential component, and Ba, Ca, and Mg can be selectively included as necessary (0 ≦ Ba, Ca, Mg ≦ 1). The Eu is used as an activator, and + 2-valent Eu2 + is used, and X is at least one of Ho, Er, Ce, YF, Cl, Br, I, P, S, N or Gd as an additive. It can be used, and can be used by selectively adjusting the doping amount from the range of 1 ppm to 500,000 ppm.

  Examples of the material used as the blue phosphor include a silicate composition material, a sulfide composition material, a nitride composition material, and an aluminate composition.

  The plurality of LED modules 120 includes a plurality of LEDs 110 arranged in a matrix with m rows and n columns. In addition, the plurality of LEDs 110 arranged in m × n can be divided into a plurality of blocks. Here, m and n are each a positive integer of 2 or more. That is, each LED module 120 includes a plurality of blocks. Further, the plurality of LEDs 110 can be driven independently for each block. Thus, the backlight unit 100 can be easily divided and driven using a block unit.

  In addition, by appropriately adjusting any one of the number of the LED modules, the number of blocks included in the LED module, and the number of LED chips per block, the amount of light necessary for the split drive LED backlight unit Can be provided as appropriate.

  Hereinafter, the selection of the appropriate number of LEDs according to the size of the backlight unit (BLU) and the adjustment range for each unit (LED module, block, chip per block) corresponding thereto will be described.

  Here, typical display sizes of 40 inches, 46 inches, 52 inches and 57 inches are considered.

  First, the total required light amount (unit: lumens) with respect to the size of each backlight unit can be set to 7000, 8000, 93000, and 13000, respectively. As shown in Table 1, the number of LED chips that can satisfy the total required light amount can be determined by the light amount of the unit LED.

Table 1 shows the required number of 4, 8, 10, and 15 lumen LEDs that are commonly used.

  As shown in Table 1, there is a slight difference in the number of LEDs required depending on the unit light quantity of the LEDs used. A large number of such LEDs need to be properly arranged so that they can have an optimal density in consideration of color uniformity and brightness.

  In the present invention, the number of LED modules, the number of blocks per module, and the number of LEDs per block are appropriately selected so that such an arrangement can be easily implemented with various areas and numbers. A method capable of obtaining optimal brightness and color uniformity conditions is provided.

In order to satisfy the conditions shown in Table 1, in each backlight unit size, the number of LED modules, the number of blocks per module, and the number of LEDs per block can be selected as shown in Table 2 below.

  In the case of 40 inches and 46 inches corresponding to the medium size, the number of the LED modules and the number of LEDs per block can be selected in the same range, and the LED backlight unit is 40 inches. The LED module is composed of 4 to 14 blocks. When the LED backlight device is 46 inches, the LED module can be composed of 5 to 15 blocks. Of course, if necessary, other adjustment factors, that is, the number of modules and the number of chips per block can be appropriately selected within the range shown in Table 2.

  In the case of 52 inches and 57 inches corresponding to a relatively large size, the number of blocks of the LED module is selected in the range of 6 to 28, and the number of LEDs for each block of the LED module is 6 to 28. A range of 24 can be selected. Preferably, the number of modules is 6 to 12 when the backlight unit is 52 inches, and 6 to 20 when the LED backlight unit is 57 inches.

  Specifically, the number of LED modules 120 is 2 to 28, and each module includes 1 to 28 blocks, and 2 to 240 LEDs may be arranged in each block. However, in the embodiment of the present invention, the number of LED modules, the number of blocks, and the number of LEDs are not limited thereto.

  The optical sheet 140 has a light transmission hole 145 corresponding to the plurality of LEDs 110, and scatters or reflects incident light in a predetermined direction, and functionally diffuses or irradiates light generated from the LEDs 110 to an upper display device. Provide a function that can.

  The optical sheet 140 according to the present invention is provided with the same size as any one of the plurality of LED modules 120 located on the lower side, and is individually attached to each LED module 120. .

  Thus, according to the present invention, the optical sheet 140 and the LED module 120 are integrally provided, and the backlight unit 100 can be reduced in size and slim.

  The sizes of the optical sheet 140 and the heat dissipation pad 130 are shown in the same manner as the LED module. However, the size of the optical sheet 140 and the heat dissipation pad 130 is smaller than the size of the LED module 120. Also good.

  Further, since the optical sheet 140 is individually attached to the upper side of each LED module 120, even if any one of the plurality of LED modules 120 is damaged, the optical sheet 140 is attached to the upper side of the damaged LED module 120. The rework process of the backlight unit 100 can be facilitated by removing only the optical sheet 140 and replacing or repairing the damaged LED module 120.

  The heat dissipating pad 130 is for releasing heat generated from the LED module 120, and may be composed of a heat dissipating plate made of synthetic resin or glass material, a plate containing a metal having high thermal conductivity, and the like. it can. The heat dissipating pad 130 on the lower surface of the LED module 120 may be deleted as necessary when the heat generation amount is small.

  In the present invention, the number of LED modules having optimum brightness and color uniformity, the number of blocks per LED module, and the number of LEDs per block can be appropriately selected. The number of pads can be selected as appropriate.

  That is, according to the present invention, the optical sheet 140, the LED module 120, and the heat dissipation pad 130 are integrally provided, the backlight unit 100 is reduced in size and slimmed, and the optical sheet 140 is individually provided above each LED module 120. Mounting and reworking of the backlight unit 100 can be facilitated.

  In the embodiment of the present invention, it has been described that the optical sheet 140 is separated in units of blocks, but similarly, the reflective sheet can be separated in units of blocks.

  As shown in FIG. 2, any one of the plurality of LED modules 120 may be provided in a state where a plurality of LEDs are arranged in a line, but the present invention is not limited thereto. The LED may be provided in various states depending on the characteristics of the backlight unit.

  Hereinafter, various examples of an arrangement form of a plurality of LEDs arranged in the LED module 120 in the backlight unit according to the embodiment of the present invention will be described with reference to the drawings.

  FIG. 3 is a perspective view showing a plurality of LED arrangement forms of the backlight unit according to the first embodiment of the present invention. As shown in FIG. 3, a plurality of LEDs 110 can be provided in a state of being arranged in two rows. That is, in one LED module 120 according to the present invention, a plurality of LEDs 110 are provided in one or more rows according to the characteristics of the backlight unit.

  FIG. 4 is a plan view showing a plurality of block forms of the backlight unit according to the second embodiment of the present invention. FIG. 5 is a plan view showing a plurality of LED arrangement forms of the backlight unit according to the second embodiment of the present invention.

  As shown in FIG. 4, the plurality of LEDs 110 on the LED module 120 can be continuously arranged in a triangular shape. Since the backlight unit 100 is divided and driven, the plurality of LEDs 110 can be divided into a plurality of blocks A, B, C, and D. Here, each block may be separated into printed circuit patterns in a circuit form so that each block can be turned on / off. Further, the heat dissipating pad on the lower surface of the LED module 120 may be deleted as necessary when the heat generation amount is small.

  The backlight unit 100 may have optimal uniformity by adjusting the LED arrangement. As shown in FIG. 5, when the LEDs 110 emit white light, the LEDs 110 are separated from each other. Further, in order for the backlight unit 100 to have optimum uniformity, the central light amount (C) of the LED unit (U) formed by a combination of arbitrary LEDs arranged at the shortest distance from each other is the light amount emitted from each LED. It should have 80% to 120% with respect to the average value.

  Here, the first distance a between the first LED 110a and the second LED 110b arranged in the same row and adjacent to each other may be 20 to 140 mm. The second distance b and the third distance e between the first LED 110a and the second LED 110b in the row direction and the third LED 110c adjacent to each other may be 15 to 90 mm. Here, since the backlight unit 100 has optimal uniformity, the second distance b and the third distance e may be the same. Also, the first distance a must be larger than the second distance b and the third distance e.

  In addition, the distance between the first LED 110a and the third LED 110c adjacent to each other in the column direction and the distance between the second LED 110b and the third LED 110c, 110e adjacent to each other in the row direction are: Each may be 8.2-70 mm.

  FIG. 6 is a plan view showing a plurality of block forms of a backlight unit according to the third embodiment of the present invention. FIG. 7 is a plan view showing a plurality of LED arrangement modes of the backlight unit according to the third embodiment of the present invention.

  As shown in FIG. 6, the plurality of LEDs 110 on the LED module 120 may be continuously arranged in a quadrangle, for example, a rectangle or a square. Since the backlight unit is divided and driven, the plurality of LEDs 110 can be divided into a large number of blocks A, B, C, and D. Here, each block can be separated in a printed circuit pattern so that it can be turned on / off for each block. Further, the heat dissipating pad on the lower surface of the LED module may be deleted as necessary when the calorific value is small.

  As shown in FIG. 7, the central light quantity (C) of the LED unit (U) formed by a combination of arbitrary LEDs arranged at the shortest distance from each other as in the case of having the above-described rectangular array is obtained from each LED. It should have 80% to 120% with respect to the average value of the amount of light emitted. For this reason, the space | interval (D1, D2) of LED110 which adjoined mutually may be 8.2 mm-70 mm, respectively. Further, the angle θ of the position where the LED is arranged with respect to the direction of the row in which the LEDs 110 are arranged may be 70 to 110 degrees.

  In such an LED array, the LED must satisfy the following conditions in order to improve color reproducibility and brightness.

  The LED chip is disposed around a blue LED chip having a dominant wavelength of 420 to 456 nm, and is excited by the blue LED chip so that white light can be emitted. A red phosphor that emits light, and a green phosphor that is disposed around the blue LED chip and emits green light when excited by the blue LED chip. At this time, the color coordinates of the red light emitted from the red phosphor are four vertices (0.6448, 0.4544), (0.8079, 0.2920), (0. 6427, 0.2905) and (0.4794, 0.4633), the color coordinates of the green light emitted by the green phosphor have four vertices (based on the CIE 1931 color coordinate system). 0.1270, 0.8037), (0.4117, 0.5861), (0.4197, 0.5316) and (0.2555, 0.5030).

Preferably, the half width (FWHM) of the emission spectrum of the blue LED chip is 10 to 30 nm, the half width of the green phosphor 105 is 30 to 100 nm, and the half width of the red phosphor is 50 to 200 nm. Can do. As a result, white light with better color uniformity and color quality is obtained. In particular, by limiting the dominant wavelength and half-value width of the blue LED chip to 420 to 456 nm and 10 to 30 nm, respectively, the efficiency of CaAlSiN ₃ : Eu red phosphor and (Sr, Ba, Ca, Mg) ₂ SiO ₄ : Eu, X (0 ≦ Ba, Ca, Mg ≦ 1) Green phosphor efficiency can be greatly improved.

  FIG. 8 is a photograph showing the luminance of the backlight unit according to the embodiment of the present invention. As shown in the figure, the central light amount (C) of the LED unit (U) formed by a combination of arbitrary LEDs arranged at the shortest distance from each other is 80% to 120% with respect to the average light amount emitted from each LED. It can be seen that there is optimal uniformity when arranging a plurality of LEDs to have.

  Therefore, in the backlight unit including a plurality of LED modules each including a plurality of LEDs as in the embodiment of the present invention, the uniformity of the backlight unit is adjusted by adjusting the LED configuration and the LED arrangement. The color reproduction rate and the luminance can be improved.

  Hereinafter, the backlight unit according to the embodiment of the present invention will be described in more detail with reference to FIGS. 9 and 10. FIG. 9 is a plan view showing the backlight unit according to the embodiment of the present invention. FIG. 10 is a circuit diagram for split driving of the backlight unit according to the embodiment of the present invention.

  Referring to FIG. 9, the backlight unit 100 according to the embodiment of the present invention may be a split drive backlight unit. For example, the backlight unit 100 includes four LED modules 120. The LED module 120 includes a wiring board 115 and a plurality of LEDs 110 mounted on the wiring board 115. For example, in each LED module 120, the LEDs 110 can be arranged in a matrix of four rows and nine columns.

  The LED module 120 can be divided into six blocks (B1 to B6). In the present invention, the blocks (B1 to B6) constituting the LED module 120 are units that can be individually driven.

  As in this embodiment, the LED chips 110 in each block (B1 to B6) can be connected in series. Here, at least one end of the circuit of each block (B1 to B6) is connected to an individual connector so that the LED chip 110 can be divided and driven for each block.

  For the connection for such a split drive, the wiring board 110 of the LED module 120 is illustrated in a form including two first connectors 130 and six second connectors 140a, 140b, 140c. Yes. The first connector 130 and the second connectors 140a, 140b, and 140c are connected to different polarities and serve to supply an external voltage to the LED 110.

  Each optical sheet (not shown) is individually attached to the upper side of each LED module 120. Accordingly, when any one of the plurality of LED modules 120 is damaged, only the optical sheet attached to the upper side of the damaged LED module 120 may be removed, and the damaged LED module 120 may be replaced or repaired. For example, the rework process of the backlight unit 100 can be easily performed.

  Referring to FIG. 10, the first to third blocks (B1 to B3) are formed by six LED chips 15 each in three column units from the first and second rows, and the same. In addition, the fourth to sixth blocks (B4 to B6) are formed by six LED chips 15 in units of three columns from the third and fourth rows.

  The LEDs of each block have a structure connected in series with each other. In the series circuit of the first to third blocks (B1, B2, B3), the plus terminal is commonly connected to the first connector (P1), and the minus terminal is divided into block units, and is divided into three individual second blocks. Each is connected to a connector (P21, P22, P23). Similarly, in the series circuit of the fourth to sixth blocks (B4, B5, B6), the plus terminal is commonly connected to the first connector, and the minus terminal is divided in units of blocks. Each of the two connectors is connected. Here, P1 and P21, P22, and P23 in FIG. 10 can be understood as elements corresponding to the first connector and the second connector shown in FIG. 9, respectively.

  As described above, the divided drive LED backlight unit according to the present invention implements the structure necessary for the divided drive by using the block unit, and can adjust the number of the required LEDs by three units.

  More specifically, the divided drive backlight unit arranges LEDs in a matrix structure formed by a plurality of rows and columns for uniform dimming as a whole, the number of LED modules, and the LED modules By appropriately adjusting the number of blocks provided by the split driving structure and the number of LED chips in each block, it is possible to easily provide the appropriate number of LED chips necessary for the area. As a result, it can be easily arranged to have the appropriate density with the required number, and as a result, local brightness control effect and overall color uniformity can be effectively achieved in medium and large displays. Can be improved.

  In addition, an optical sheet (not shown) is individually attached to the upper side of each LED module 120. Accordingly, even if any one of the plurality of LED modules 120 is damaged, only the optical sheet attached to the upper side of the damaged LED module 120 is removed, and the damaged LED module 120 is replaced or repaired. The rework process of the backlight unit 100 can be facilitated.

  In the embodiment of the present invention, the LED modules are described as being arranged in the longitudinal direction, but the present invention is not limited to this.

  FIG. 11 is a perspective view showing an LED module of another arrangement form of the backlight unit according to the embodiment of the present invention.

  As shown in the figure, the LED modules 120 can be arranged so as to surround a central fixed region. In FIG. 10, four LED modules are shown, but actually four or more LED modules can surround a central fixed region. The heat dissipating pad on the lower surface of the LED module may be deleted as necessary when the amount of heat generated is small.

  The embodiment disclosed above should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims for patent.

100 Backlight unit 110 LED
120 LED module 130 Heat dissipation pad 140 Optical sheet

Claims (28)

A plurality of LEDs that generate light;
A plurality of LED modules having a printed circuit board for supporting and driving the plurality of LEDs;
Including
The plurality of LED modules includes a plurality of LEDs arranged in a matrix of two or more rows and two or more columns, and the plurality of LEDs are divided into a plurality of blocks and can be turned on / off for each block. Thus, each block is separated in a circuit by a printed circuit pattern.   The number of the LED modules is 6 to 12 when the size of the LED backlight unit is 40, 46, and 52 types, and 6 to 20 when the size is 57 types. The backlight unit according to 1.   In the LED module, when the size of the LED backlight unit is 40 type, the number of modules is 6 to 12, the number of blocks per module is 4 to 14, and the number of LEDs per block is The backlight unit according to claim 1, wherein the number is 6 to 24.   In the LED module, when the size of the LED backlight unit is 46 type, the number of the modules is 6 to 12, the number of blocks per module is 5 to 15, and the number of LEDs per block is The backlight unit according to claim 1, wherein the number is 6 to 24.   The LED module has a backlight unit size of 52 type, the number of modules is 6 to 12, the number of blocks per module is 6 to 28, and the number of LEDs per block is The backlight unit according to claim 1, wherein the number is 6 to 24.   In the LED module, when the size of the LED backlight unit is 57 type, the number of modules is 6 to 20, the number of blocks per module is 6 to 28, and the number of LEDs per block is The backlight unit according to claim 1, wherein the number is 6 to 24.   The backlight unit according to claim 1, wherein the LEDs in each of the plurality of blocks are connected in series.   The backlight unit according to claim 1, wherein the plurality of LEDs include a blue LED, a green LED, and a red LED.   The backlight unit according to claim 1, wherein the plurality of LEDs emit white light.   The backlight unit according to claim 9, wherein the white light includes a red phosphor and a green phosphor in the blue LED.   The backlight unit according to claim 10, wherein the red phosphor includes a nitride-based or sulfide-based red phosphor.   The backlight unit according to claim 10, wherein the green phosphor includes any one of a silicate system, a sulfide system, and a nitride system. A plurality of LEDs that generate light;
A plurality of LED modules having a printed circuit board for supporting and driving the plurality of LEDs;
Including
The plurality of LED modules includes a plurality of white LEDs arranged in a matrix of two or more rows and two or more columns, and the white LEDs include a red phosphor and a green phosphor in a blue LED. The color coordinates of the red light emitted from the red phosphor are four vertices (0.6448, 0.4544), (0.8079, 0.2920), (0.6427, 0) based on the CIE 1931 color coordinate system. 2905) and (0.4794, 0.4633), the color coordinates of the green light emitted by the green phosphor are four vertices (0.1270, 0.1270, 0.8037), (0.4117, 0.5861), (0.4197, 0.5316), and (0.2555, 0.5030). Ito unit.   The plurality of LEDs include an LED unit composed of a combination of arbitrary LEDs arranged at the shortest distance from each other, and the central light amount of the LED unit is 80% to 120% with respect to the average value of the light amount emitted from each LED. The backlight unit according to claim 13, wherein the backlight unit is provided.   The plurality of LEDs are continuously arranged in a triangular shape, and the distance between the first LED and the second LED arranged in the same row is 20 to 140 mm. Item 14. The backlight unit according to Item 13.   The plurality of LEDs are continuously arranged in a triangular shape, and a column direction distance or a row direction distance between adjacent LEDs in the row and the column is 8.2 to 70 mm. The backlight unit according to claim 13.   The backlight unit according to claim 13, wherein the plurality of LEDs have a rectangular shape and are continuously arranged, and a distance between adjacent LEDs is 8.2 to 70 mm.   The plurality of LEDs are arranged in a continuous manner having a quadrangular shape, and an angle of an arrangement position of the LEDs with respect to a direction of the arrayed row of LEDs is 70 to 110 degrees. The backlight unit according to 13.   The plurality of LED modules can be divided into a plurality of blocks, and each block is separated by a printed circuit pattern so as to be turned on / off for each block. Backlight unit.   The plurality of LED modules can be divided into a large number of blocks, and each block is separated by a printed circuit pattern so that each block can be turned on / off. The LEDs in each block are connected in series. The backlight unit according to claim 13.   The backlight unit according to claim 13, wherein the red phosphor includes a nitride-based or sulfide-based red phosphor.   The backlight unit according to claim 13, wherein the green phosphor includes any one of a silicate system, a sulfide system, and a nitride system. A plurality of LEDs that generate white light;
A plurality of LED modules having a printed circuit board for supporting and driving the plurality of LEDs;
Including
The plurality of LED modules can be divided into a large number of blocks, and each block is separated by a printed circuit pattern so that each block can be turned on / off. A backlight unit arranged so as to surround an area.   24. The backlight unit according to claim 23, wherein the LEDs provided in each of the plurality of blocks are connected in series.   The backlight unit according to claim 23, wherein a distance between adjacent LEDs among the plurality of LEDs is 8.2 to 70 mm.   The backlight unit according to claim 23, wherein the white light includes a red phosphor and a green phosphor in a blue LED.   27. The backlight unit according to claim 26, wherein the red phosphor includes a nitride-based or sulfide-based red phosphor.   27. The backlight unit according to claim 26, wherein the green phosphor includes any one of a silicate system, a sulfide system, and a nitride system.

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