CN110632795B

CN110632795B - Backlight source, back plate thereof and manufacturing method

Info

Publication number: CN110632795B
Application number: CN201910910880.9A
Authority: CN
Inventors: 班圣光; 刘松
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2019-09-25
Filing date: 2019-09-25
Publication date: 2022-09-02
Anticipated expiration: 2039-09-25
Also published as: CN110632795A

Abstract

The invention discloses a backlight source, a back plate thereof and a manufacturing method, and belongs to the field of displays. The backlight backboard is provided with a light emitting area and a binding area, the light emitting area is provided with a plurality of partitions, a group of LED bonding pads are arranged in each partition, a plurality of IC bonding pads are arranged in the binding area, the group of LED bonding pads comprises at least two LED bonding pad pairs, and each LED bonding pad pair comprises an LED anode bonding pad and an LED cathode bonding pad. A group of LED bonding pads in each partition are connected with the IC bonding pads in the binding region through an anode wire and a cathode wire. By individually controlling each of the partitions, high contrast display of the backlight can be achieved. And each partition only needs one anode wire and one cathode wire to be connected with the binding area, so that the wire layout on the backlight backboard can be simplified.

Description

Backlight source, back plate thereof and manufacturing method

Technical Field

The invention relates to the field of displays, in particular to a backlight source, a back plate thereof and a manufacturing method.

Background

A Liquid Crystal Display (LCD) generally includes two major portions, namely a backlight source and a Display panel. The backlight source can be a direct Light Emitting Diode (LED) backlight source, and the requirement of the liquid crystal display for high Contrast Ratio can be met by performing Area control on the backlight source.

At present, the number of LEDs on the backlight source is small, and each LED in each partition can be connected to the driving circuit through a wire. However, when the number of LEDs increases, this solution may lead to a complicated layout of the traces on the back plate of the backlight, and it is difficult to implement a backlight with a large number of LEDs.

Disclosure of Invention

The embodiment of the invention provides a backlight source, a back plate and a manufacturing method thereof, which can simplify the wiring layout on the back plate of the backlight source and realize the backlight source with a large number of LEDs. The technical scheme is as follows:

in one aspect, the present disclosure provides a backlight backplane having a light-emitting area and a binding area located at a periphery of the light-emitting area;

the light-emitting region is provided with a plurality of partitions, a group of LED bonding pads are arranged in each partition, a plurality of IC bonding pads are arranged in the binding region, the group of LED bonding pads comprises at least two LED bonding pad pairs, and each LED bonding pad pair comprises an LED anode bonding pad and an LED cathode bonding pad;

and the group of LED bonding pads in each partition are connected with the IC bonding pads in the binding region through an anode wire and a cathode wire.

In an implementation manner of the embodiment of the present invention, the group of LED pads includes at least two strings of LED pads, and each string of LED pads includes at least two LED pad pairs;

at least two LED bonding pad pairs in the same LED bonding pad string are sequentially connected in series, and an LED anode bonding pad of one LED bonding pad pair is connected with an LED cathode bonding pad of the other LED bonding pad pair;

in the same group of LED bonding pads, the LED anode bonding pad at one end of each string of the LED bonding pads is connected with the anode wire, and the LED cathode bonding pad at the other end of each string of the LED bonding pads is connected with the cathode wire.

In one implementation of the embodiment of the present invention, the plurality of partition arrays are distributed in the light emitting area, the number of rows of the partitions ranges from 30 to 60, and the number of columns of the partitions ranges from 10 to 20.

In one implementation of an embodiment of the invention, the IC pads include a plurality of IC anode pads and a plurality of IC cathode pads;

each partition is connected with one IC anode bonding pad through one anode wire, and different partitions are connected with different IC anode bonding pads;

the partitions in the same row are divided into at least two groups, each group of partitions is connected with one IC cathode bonding pad through one cathode wire, and the partitions in different groups are connected with different IC cathode bonding pads.

In an implementation manner of the embodiment of the present invention, the backlight backplane includes a substrate, and a first insulating layer, a metal routing layer, a second insulating layer, and a pad layer stacked on the substrate, where the LED pad and the IC pad are both located on the pad layer, and the anode routing and the cathode routing are both located on the metal routing layer;

the second insulating layer is provided with a via hole, and the pad layer is connected with the metal wiring layer through the via hole.

In an implementation manner of the embodiment of the present invention, at least one of the metal routing layer and the pad layer is made of the following materials: copper, a molybdenum niobium alloy, or a molybdenum niobium alloy/copper/molybdenum niobium alloy laminate.

In one implementation of the embodiment of the invention, the thickness of the metal routing layer ranges from 1.5 μm to 2.5 μm, and the width of the metal routing layer ranges from 0.3mm to 0.5 mm.

In another aspect, the present invention provides a backlight source, which includes the backlight source backplane described above, and a micro light emitting diode bound on the backlight source backplane.

On the other hand, the invention provides a method for manufacturing a backlight backboard, which is used for manufacturing the backlight backboard, and the method for manufacturing the backlight backboard comprises the following steps:

manufacturing a first insulating layer on a substrate;

manufacturing a metal wiring layer on the first insulating layer, wherein the anode wiring and the cathode wiring are both positioned on the metal wiring layer;

manufacturing a second insulating layer on the metal wiring layer;

carrying out graphical processing on the second insulating layer, and manufacturing a via hole connected with the metal wiring layer;

and manufacturing a pad layer on the second insulating layer, wherein the LED pad pair and the IC pad are both positioned on the pad layer, and the pad layer is connected with the metal routing layer through the via hole.

In another aspect, the present invention provides a method for manufacturing a backlight, where the method for manufacturing a backlight includes:

manufacturing the backlight backboard by using the manufacturing method of the backlight backboard;

binding a micro light emitting diode to the backlight backplane.

The technical scheme provided by the embodiment of the invention has the following beneficial effects:

partitioning a light emitting area of the backlight backboard, wherein a group of LED bonding pads are uniformly arranged in each partition, each group of LED bonding pads comprises at least two LED bonding pad pairs, and the LED bonding pad pairs can be bound with LEDs; a group of LED bonding pads in the subarea are connected with the IC bonding pads in the binding area through an anode wire and a cathode wire; the IC bonding pad in the binding region of the backlight backboard can be bound with the integrated circuit, so that the connection between the LED and the integrated circuit is realized, and the driving of the backlight is realized. By individually controlling each of the sections, high contrast display of the backlight can be achieved. And only one anode wire and one cathode wire of each group of partitioned LED pads are connected with the binding area, so that the wire layout on the backlight backboard can be simplified.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a backlight backplane according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a partition of a backlight backplane according to an embodiment of the present disclosure;

fig. 3 is a schematic connection diagram of partitions of a backlight backplane according to an embodiment of the present disclosure;

fig. 4 is a schematic cross-sectional view of a backlight backplane according to an embodiment of the present disclosure;

fig. 5 is a block diagram of a manufacturing process of a backlight backplane according to an embodiment of the present disclosure;

fig. 6 to fig. 11 are schematic flow charts illustrating a method for manufacturing a backlight backplane according to an embodiment of the present invention;

FIG. 12 is a schematic cross-sectional view of a backlight according to an embodiment of the invention;

fig. 13 is a block diagram of a manufacturing process of a backlight source according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a backlight backplane according to an embodiment of the present disclosure. Referring to fig. 1, the backlight backplane 10 has a light emitting region 101 and a binding region 102 located at the periphery of the light emitting region 101.

The light emitting region 101 has a plurality of partitions 111, a group of LED pads 112 is disposed in each partition 111, a plurality of IC pads 121 is disposed in the bonding region 102, the group of LED pads 112 includes at least two LED pad pairs 113, and each LED pad pair 113 includes an LED anode pad 113A and an LED cathode pad 113B. A group of LED pads 112 within each zone 111 are connected to IC pads 121 within the bonding area 102 by one anode trace 114 and one cathode trace 115.

The LED pad pair 113 is used for Bonding with the LED. The LED provides a light source for the liquid crystal display, so that the liquid crystal display can display pictures. A group of LED pads 112 in the partition 111 are connected to the IC pads 121 in the bonding area 102 through an anode trace 114 and a cathode trace 115, and the IC pads 121 in the bonding area 102 of the backlight backplane 10 can be bonded to the integrated circuit, so as to implement connection between the LEDs and the integrated circuit and drive the backlight. By individually controlling each of the segments 111, a high contrast display of the backlight can be achieved. And only one anode trace 114 and one cathode trace 115 are needed for connecting one group of LED pads 112 in each partition 111 with the bonding area 102, which can simplify the trace layout on the backlight backplane 10.

Fig. 2 is a schematic structural diagram of a partition of a backlight backplane according to an embodiment of the present disclosure. Referring to fig. 2, a group of LED pads includes at least two strings of LED pads 112, each string of LED pads 112 including at least two LED pad pairs 113. At least two LED bonding pad pairs 113 in the same LED bonding pad 112 are sequentially connected in series, and in two adjacent LED bonding pad pairs 113, an LED anode bonding pad 113A of one LED bonding pad pair 113 is connected to an LED cathode bonding pad 113B of another LED bonding pad pair 113. In the same group of LED pads 112, the LED anode pads 113A at one end of each string of LED pads 112 are all connected to the anode traces 114, and the LED cathode pads 113B at the other end of each string of LED pads 112 are all connected to the cathode traces 115.

Each group of LED pads comprises at least two strings of LED pads 112, each string of LED pads 112 comprises at least two LED pad pairs 113, i.e. each section comprises at least 4 LED pad pairs 113. Each LED bonding pad pair 113 is bound to an LED, that is, the minimum number of LEDs connected to the LED bonding pad pair 113 in one partition is ensured to be 4, that is, the minimum number of LEDs in one partition of the backlight source is 4, the LEDs of the backlight source are partitioned, and partition control of the backlight source is realized.

Each partition 111 only needs one anode trace 114 and one cathode trace 115 to connect with the bonding area 102, and each LED does not need to be separately connected with the bonding area 102, thereby simplifying the trace layout on the backlight backplane. The LED anode pads 113A at one end of each string of LED pads 112 are all connected to the anode trace 114, and the LED cathode pads 113B at the other end are all connected to the cathode trace 115. The anode trace 114 and the cathode trace 115 are connected to the IC pads 121 in the bonding region, and the bonding region is connected to the integrated circuit, that is, each string of LED pads 112 is connected to the integrated circuit.

As shown in fig. 2, a group of LED pads includes two strings of LED pads 112, and each string of LED pads 112 includes two LED pad pairs 113 connected in series in sequence, so that the partitions 111 can be ensured to be sufficient to improve the display contrast. In other implementations, a group of LED pads may include more than two strings of LED pads 112, and each string of LED pads 112 may include more than two LED pad pairs 113 serially connected together in sequence.

The LED may be a Mini Light Emitting Diode (Mini LED), a sub-millimeter LED, or a Micro LED.

The Mini LED backlight realizes the backlight effect by utilizing the extremely large number of ultra-small-sized LED lamp sets, and the size and the Pitch (English: Pitch) of the Mini LED are small, so that the Mini LED backlight not only can more finely adjust the number of Dimming Zones (Local Dimming Zones) to achieve the effect of High Dynamic Range (HDR) and High contrast, but also can shorten the Optical Distance (OD) to reduce the Thickness (OD) of the whole machine and achieve the thinning requirement. Micro LED is a new generation display technology, is LED Micro and matrixing technology, and is smaller in size compared with Mini LED, namely, the number of dimming subareas can be further increased, and the contrast of the liquid crystal display is improved.

A string of LED pads 112 refers to: at least two LED pad pairs 113 are arranged in sequence, and the LED anode pad 113A of one LED pad pair 113 is connected to the LED cathode pad 113B of the adjacent LED pad pair 113, i.e., at least two LED pad pairs 113 are connected in series. Thus, two ends of at least two LED pad pairs 113 connected in series are respectively one LED anode pad 113A and one LED cathode pad 113B. This ensures that one LED anode pad 113A at one end of each string of LED pads 112 can be connected to the anode trace 114 and one LED cathode pad 113B at the other end can be connected to the cathode trace 115, i.e., each string of LED pads 112 is connected in parallel.

By arranging the LED pad pairs 113 in the partitions 111 in such a connection manner, the partitions 111 can be set to be rectangular, and the liquid crystal display is generally rectangular, so that partition control of the backlight is more easily achieved.

As shown in fig. 1, a plurality of partition 111 arrays are distributed in the light emitting region 101. Illustratively, the number of rows of the partition 111 ranges between 30 and 60, and the number of columns of the partition 111 ranges between 10 and 20. The partitioning scheme described above may be suitable for high definition display panels, such as 2K, 4K, 8K, and even higher resolution display panels. The number of the partitions 111 on the light-emitting region 101 is enough, so that high-contrast display of the backlight source can be realized, and the situation that the number of the partitions 111 is too large, so that too much Current (english: Current) is borne by the traces on the back plate of the backlight source is avoided.

For example, the partition 111 on the light emitting region 101 may have 40 rows and 15 columns.

Referring to fig. 1, the IC pads 121 include a plurality of IC anode pads 121A and a plurality of IC cathode pads 121B.

Fig. 3 is a schematic connection diagram of partitions of a backlight backplane according to an embodiment of the present disclosure. Referring to fig. 3, each partition 111 is connected to one IC anode pad 121A through one anode trace 114, and different partitions 111 are connected to different IC anode pads 121A. The partitions 111 in the same row are divided into at least two groups, the partitions 111 in the same group are arranged at intervals, the partitions 111 in different groups are periodically and alternately arranged, each group of partitions 111 is respectively connected with one IC cathode pad 121B through one cathode trace 115, and the partitions 111 in different groups are connected with different IC cathode pads 121B.

In the embodiment of the present invention, the number of the LED bonding pad pairs 113 on the backlight back plate is increased, and at this time, the partitions 111 in the same row are grouped, and each group is connected to one IC cathode bonding pad 121B, so that on one hand, excessive routing caused by that each partition 111 is connected to the IC cathode bonding pad 121B alone can be avoided, and on the other hand, too much driving current is caused by that all the partitions 111 are connected to the IC cathode bonding pad 121B through one routing, and the routing cannot bear too much current, which causes the backlight to fail to operate normally.

As shown in fig. 1, the IC anode pads 121A and the IC cathode pads 121B in the bonding region 102 are not paired, and the number of the IC anode pads 121A is greater than that of the IC cathode pads 121B, so that the circuit connection can be completed. The IC anode pad 121A and the IC cathode pad 121B shown in fig. 1 are only examples, and the IC anode pad 121A and the IC cathode pad 121B may be arranged according to practical applications.

In order to clearly show the routing manner of the partitions, fig. 3 only lists the routing connections of the partitions 111 in one row, and the actual backlight backplane includes multiple rows. And the partitions in a row in fig. 3 comprise two groups, each group connected to one IC cathode pad 121B by one cathode trace 115. In other implementations, the number of groups of partitions 111 of the same row may be greater than 2. For example, partitions 111 of the same row may be divided into 3 groups.

Since each partition 111 is connected to a different IC anode pad 121A, the luminance of the partition can be individually controlled by controlling the current output condition of the IC anode pad 121A, and even if each group of partitions 111 is connected to one IC cathode pad 121B through one cathode trace 115, the individual control of the partitions 111 is not affected.

Fig. 4 is a schematic cross-sectional view of a backlight backplane according to an embodiment of the present disclosure. Referring to fig. 4, the backlight back plate includes a substrate 103, and a first insulating layer 104, a metal wiring layer 105, a second insulating layer 106, and a pad layer 107 stacked on the substrate 103. The LED pad 112 and the IC pad 121 are both on the pad layer 107, and the anode trace and the cathode trace are both on the metal trace layer 105.

The second insulating layer 106 is provided with a via 161, and the pad layer 107 is connected to the metal wiring layer 105 through the via 161.

Exemplarily, the substrate 103 may be a glass substrate.

Illustratively, the first insulating layer 104 may be a silicon nitride (SiNx) insulating layer.

Illustratively, the thickness of the first insulating layer 104 is less than 0.5 μm, so as to avoid that the thickness of the first insulating layer 104 is too thin, which cannot ensure the insulating effect of the first insulating layer 104, and at the same time, avoid that the thickness of the first insulating layer 104 is too thick, which causes the overall thickness of the back plate to be too large, which is not favorable for thinning.

For example, the thickness of the first insulating layer 104 may be 0.4 μm.

In the embodiment of the present invention, the cross section of the trace in the metal routing layer 105 is a trapezoid structure, and the metal routing layer 105 can be formed by etching. As shown in fig. 4, the side of metal routing layer 105 with a trapezoid structure forms an angle with the bottom of metal routing layer 105, and the angle ranges from 45 ° to 50 °.

Illustratively, the second insulating layer 106 may include a silicon nitride insulating layer 162 and a planarization layer 163 disposed on the silicon nitride insulating layer 162.

Silicon nitride insulating layer 162 is used to separate adjacent metal routing layers 105 and prevent erroneous electrical connection between adjacent metal routing layers 105. The flat layer 163 can reduce the difference of the wiring section, reduce the difficulty of the subsequent work, and the flat layer 163 can also play an insulating role, thereby ensuring the insulating effect of the second insulating layer 106.

Illustratively, the thickness of the silicon nitride insulating layer 162 ranges from 0.05 μm to 0.1 μm, which not only ensures the insulating effect of the silicon nitride insulating layer 162, but also avoids the problem that the thickness of the silicon nitride insulating layer 162 is too thick, which results in an excessively large thickness of the back plate and is not favorable for thinning.

For example, the silicon nitride insulating layer 162 may have a thickness of 0.07 μm.

Illustratively, the material of the planarization layer 163 may be Resin (english: Resin), which has insulation and can well separate the adjacent metal wiring layers 105.

Illustratively, the thickness of the planarization layer 163 ranges between 1.5 μm and 2.5 μm, which both ensures that the planarization layer 163 can separate the adjacent metal routing layers 105 and avoids the planarization layer 163 from being too thick and increasing the overall thickness of the backplane.

For example, the thickness of the planarization layer 163 may be 2.0 μm.

In the embodiment of the invention, the LED bonding pad pair 113 and the IC bonding pad 121 are both located on the bonding pad layer 107, and the bonding pad layer 107 is connected to the metal routing layer 105 through the via hole 161 on the second insulating layer 106, so that the LED bonding pad pair 113 is connected to the IC bonding pad 121. And, the LEDs on the backlight source connected with the LED pad pair 113 can be connected in series and parallel through the metal wiring layer 105.

As shown in fig. 4, the metal wiring layer 105 includes adhesive layers 151 and a metal layer 152 disposed between the adhesive layers 151. Illustratively, the adhesion layer 151 may be a molybdenum-niobium alloy (chemical formula: MoNb), and the metal layer 152 may be copper (chemical formula: Cu). Similarly, the pad layer 107 may be designed correspondingly to the metal layer 105. That is, at least one of the metal wiring layer 105 and the pad layer 107 is made of the following materials: copper, molybdenum niobium alloy, or molybdenum niobium alloy/copper/molybdenum niobium alloy laminate. The copper and molybdenum-niobium alloy have conductivity, can ensure the conductivity of the metal wiring layer 105 and the bonding pad layer 107,

in the backlight back plate, the metal wiring layer 105 needs to be fixed on the first insulating layer 104, and the metal wiring layer 105 is arranged to be a molybdenum-niobium alloy/copper/molybdenum-niobium alloy lamination, that is, the adhesion layer 151 below the metal wiring layer 105 is in contact with the first insulating layer 104, and the molybdenum-niobium alloy has adhesion property, so that the metal wiring layer 105 can be well fixed on the first insulating layer 104; meanwhile, the molybdenum-niobium alloy can protect copper and prevent the copper from being oxidized. The copper has good conductivity, can ensure the electric connection between the structures, has small resistance, can reduce the current loss during the work, has low price and can reduce the manufacturing cost of the back plate.

Meanwhile, the adhesion layer 151 above the metal wiring layer 105 is connected with the pad layer 107, and the molybdenum-niobium alloy has adhesion, so that the metal wiring layer 105 and the pad layer 107 can be stably connected.

As shown in fig. 4, metal routing layer 105 is provided as a molybdenum niobium alloy/copper/molybdenum niobium alloy stack, and in other implementations, metal routing layer 105 may also be a copper layer or a molybdenum niobium alloy layer. The pad layer 107 may also be provided as a molybdenum niobium alloy/copper/molybdenum niobium alloy laminate; the pad layer 107 may be a copper layer or a molybdenum-niobium alloy layer.

Illustratively, the thickness of metal routing layer 105 ranges between 1.5 μm and 2.5 μm, and the width of metal routing layer 105 ranges between 0.3mm and 0.5 mm. The metal wiring layer 105 with the thickness and the width can ensure that the metal wiring layer 105 can transmit large current, so that the metal wiring layer 105 can bear large current, LED in a backlight source is driven to work, and meanwhile, the thickness and the width of the metal wiring layer 105 are prevented from being too large, and the thickness of the backlight is increased.

For example, metal routing layer 105 may have a thickness of 2.0 μm and metal routing layer 105 may have a width of 0.38 mm.

Illustratively, the thickness of the pad layer 107 ranges between 0.3 μm and 0.6 μm. Not only ensures the strength of the pad layer 107, but also avoids the increase of the thickness of the back plate due to the excessive thickness of the pad layer 107.

For example, the thickness of the pad layer 107 may be 0.5 μm.

As shown in fig. 4, the backlight back plate further includes a third insulating layer 108, a reflective layer 109, and a protective layer 110 covering the reflective layer 109.

As shown in fig. 4, third insulating layers 108 are disposed between the pad layers 107, and the pad layers 107 are located between the third insulating layers 108. The third insulating layer 108 is arranged to prevent the pad layer 107 from being connected to other structures above the third insulating layer 108, and simultaneously, the adjacent pad layers 107 can be separated to prevent erroneous electrical connection between the pad layers 107 during operation.

Illustratively, the material of the third insulating layer 108 may be silicon nitride, which has good insulating property, and can separate other structures above the third insulating layer 108 from the pad layer 107, and can also separate the pad layer 107 between adjacent structures.

Illustratively, the thickness of the third insulating layer 108 ranges from 0.05 μm to 0.2 μm, which both ensures that the third insulating layer 108 can perform the spacing function and avoids the third insulating layer 108 being too thick, thereby increasing the thickness of the back plate.

For example, the thickness of the third insulating layer 108 may be 0.1 μm.

The reflective layer 109 is disposed over the third insulating layer 108. The LED pad 112 in the pad layer 107 is connected to the LED, the LED emits light towards the side far from the reflective layer 109, but still a part of the light is emitted towards the bottom of the back plate, and the reflective layer 109 is used for reflecting the part of the light, so that the part of the light emits light from the side far from the reflective layer 109 again, and the utilization rate of the light is improved.

Illustratively, the reflective layer 109 may be an indium tin oxide/silver/indium tin oxide stack. The silver (chemical formula: Ag) has good reflection performance, can well reflect the light emitted by the LED, and improves the utilization rate of the light. Indium Tin Oxide (ITO) has good light transmittance, does not affect the reflection effect of the reflective layer 109, and can well protect the reflective layer 109.

Illustratively, the thickness of the reflective layer 109 ranges from 0.05 μm to 0.2 μm, which ensures the strength of the reflective layer 109 and prevents the reflective layer 109 from being too thick, thereby increasing the overall thickness of the liquid crystal display.

For example, the thickness of the reflective layer 109 may be 0.1 μm.

The protective layer 110 is wrapped on the reflective layer 109 and is used for protecting the reflective layer 109 and preventing the reflective layer 109 from being oxidized by contact with air and affecting the reflective effect of the reflective layer 109.

Illustratively, the protective layer 110 may be a silicon nitride protective layer, which can protect the reflective layer 109 well.

Fig. 5 is a block diagram of a manufacturing process of a backlight backplane according to an embodiment of the present invention. Referring to fig. 5, the process of manufacturing the backlight backplane includes:

step 201: a first insulating layer is formed on a substrate.

Fig. 6 to fig. 11 are schematic flow charts of a method for manufacturing a backlight backplane according to an embodiment of the present disclosure. The process flow of manufacturing the back plate of the backlight source is described with reference to fig. 6 to 11. The parameters of the materials and the thicknesses of the film layers described below are the same as those of the corresponding film layers in the structure of the backlight back plate, and the description thereof is not repeated here.

As shown in fig. 6, a first insulating layer 104 is formed on the substrate 103, and the first insulating layer 104 covers the entire substrate 103, so that the first insulating layer 104 can separate the entire substrate 103 from other structures.

Illustratively, the first insulating layer 104 may be disposed on the substrate 103 by deposition.

Step 202: and manufacturing a metal wiring layer on the first insulating layer.

As shown in fig. 7, metal wiring layers 105 are arranged at intervals on the first insulating layer 104.

For example, a metal routing layer 105 as shown in fig. 7 can be obtained by first forming a whole metal routing layer by deposition and then etching the whole metal routing layer.

As shown in fig. 7, the cross-section of the traces in the metal trace layer 105 has a trapezoidal structure, and the metal trace layer 105 includes adhesive layers 151 and a metal layer 152 disposed between the adhesive layers 151. And the bottom edge of metal routing layer 105 with the trapezoid structure is located on first insulating layer 104, so that stability of metal routing layer 105 is guaranteed. Wherein adhesive layer 151 at the bottom edge of metal trace layer 105 is connected to first insulating layer 104, adhesive layer 151 having a viscosity capable of fixing the entire metal trace layer 105 on first insulating layer 104.

Step 203: and manufacturing a second insulating layer on the metal wiring layer.

As shown in fig. 8, a second insulating layer 106 is formed on the metal wiring layer 105.

Illustratively, the second insulating layer 106 may be fabricated by deposition.

As shown in fig. 8, the second insulating layer 106 includes a silicon nitride insulating layer 162 and a planarization layer 163 disposed on the silicon nitride insulating layer 162.

The silicon nitride insulating layer 162 in fig. 8 has a uniform thickness and is easy to fabricate. In other implementations, the thickness of the silicon nitride insulating layer 162 may also be non-uniformly disposed.

Step 204: and carrying out graphical processing on the second insulating layer, and manufacturing a via hole communicated with the metal wiring layer.

As shown in fig. 9, second insulating layer 106 on the top surface of metal routing layer 105 is perforated to enable electrical connection of the top surface of metal routing layer 105 to other structures through vias 161.

Illustratively, the via 161 may be formed by etching.

As shown in fig. 9, the via 161 penetrates through the planarization layer 163 on the silicon nitride insulating layer 162, ensuring that the via 161 can penetrate through the entire second insulating layer 106.

Step 205: and manufacturing a pad layer on the second insulating layer, wherein the pad layer comprises an LED pad and an IC pad.

As shown in fig. 10, a pad layer 107 is formed on the second insulating layer 106, and the pad layer 107 is connected to the metal wiring layer 105 through a via 161.

For example, a whole layer of pad layer may be formed on the second insulating layer 106 by deposition, and then the whole layer of pad layer is etched, so as to obtain the pad layer 107 shown in fig. 10.

Further, the method may further include fabricating a third insulating layer 108, a reflective layer 109, and a protective layer 110.

As shown in fig. 11, a third insulating layer 108 is formed on the pad layer 107, and a reflective layer 109 is formed on the third insulating layer 108.

Illustratively, the third insulating layer 108 may be fabricated on the pad layer 107 by deposition. A full-thickness reflective layer can be formed on the third insulating layer 108 by deposition, and then etched to obtain the reflective layer 109 shown in fig. 11.

On the basis of the backlight backplane shown in fig. 11, the third insulating layer 108 is etched to expose the pad layer 107 from the third insulating layer 108. Meanwhile, a protective layer 110 is formed on the reflective layer 109, so that the backlight backplane shown in fig. 4 can be obtained.

The embodiment of the invention provides a backlight source, which comprises the backlight source backboard and a micro light-emitting diode bound on the backlight source backboard.

Fig. 12 is a schematic cross-sectional view of a backlight according to an embodiment of the present invention. Referring to fig. 12, the backlight includes a backlight back plate 10 as shown in fig. 4, and micro light emitting diodes 20 bound on the backlight back plate 10.

The backlight shown in fig. 12 shows only two micro-leds 20, and the two micro-leds 20 are connected in series through the bonding pad. Fig. 12 is an example, and in practical applications, different numbers of micro light emitting diodes may be connected in series according to actual requirements, and then the micro light emitting diodes connected in series are connected in parallel.

Fig. 13 is a block diagram of a manufacturing process of a backlight source according to an embodiment of the present invention. Referring to fig. 13, the backlight source manufacturing process includes steps 201 to 205, and the backlight source back plate 10 is manufactured through steps 201 to 205, which are not described herein again.

The backlight source manufacturing process further includes step 206: the micro light emitting diodes are bound to the backlight backplane. I.e. a backlight as shown in fig. 12 is obtained.

The micro leds 20 are fabricated prior to bonding and then bonded to the backlight backplane 10.

Illustratively, the micro light emitting diode 20 may be fabricated by a Quantum Dot (QD) or Nitride semiconductor (Nitride) process.

In a conventional large-sized lcd, a large partition of several or more than ten LEDs is typically used for display, which is a common backlight scheme in the related art. However, the lcd of this solution has a low display contrast ratio, and is the biggest disadvantage of LED display compared with Organic Light-Emitting Diode (OLED) display.

In order to verify the technical effect of the invention, the technical scheme of the invention is experimentally verified, and in order to increase the partition of the backlight, the Mini LED is used as the light source of the backlight in the experiment. For comparison, the control group used a conventional backlight source, which used a common LED as the light source of the backlight source.

In the experiment of the present invention, taking a 12.3 inch lcd as an example, the Resolution (english: Resolution) of the 12.3 inch lcd was 1920 × 720, and the outer dimension (english: Outline) was 306.7mm × 123.5 mm. The backplane source in the invention is divided into 600 partitions, each partition has 4 Mini LEDs, and 2400 Mini LEDs in total. In contrast, in the related art, 36 and 80 common LEDs are generally used as backlights of the backlight source to light the entire surface of the liquid crystal display, and the divisional display is not used. The contrast ratio of the liquid crystal display using 36 and 80 common LEDs in the related art is generally 1000: 1, the contrast ratio of the liquid crystal display adopting 2400 Mini LEDs in the experiment can reach 400000: 1, high dynamic range image display can be realized at the same time. In the experiment, two backlight fabrication schemes, QD and Nitride, were used for the 12.3 inch Mini LED backlight, in comparison to the related art. See table 1 for specific parameters of the experiment.

TABLE 1 comparison of common LED backlight and Mini LED backlight parameters provided herein

As can be seen from table 1, the Color Gamut (english: Color Gamut), the contrast ratio, the module Brightness (english: MDL Brightness), and the like of the backlight using the Mini LED are all larger than those of the backlight of the same size using the common LED. Meanwhile, in the related art, backlight is generally prepared on a Printed Circuit Board (PCB) backplane when performing backlight partition control, but the method requires the PCB to have a larger thickness and also increases the manufacturing cost. The thickness of the back light source of the backlight source adopting the Mini LED is smaller, so that the thickness of the whole backlight source is smaller than that of the backlight source adopting the common LED and having the same size. As can be seen from table 1, the display effect obtained by the QD and Nitride manufacturing schemes is better than that of the backlight source with the same size using the common LED. In practical applications, one of QD and Nitride can be selected to make backlight.

As shown in table 1, although the current of the single Mini LED is smaller than the current passed by the single LED in the related art, the total current is large, which is 4-5 orders of magnitude larger than the current on the backlight back plate of the normal LED, because the number of Mini LEDs in the present invention is large. Therefore, the Mini LED is driven to work by transmitting large current to realize the excellent display effect in the structure, and the backlight source is partitioned by the invention, so that the wiring layout on the backlight source backboard can be simplified. Meanwhile, the thickness of the metal wiring layer is increased, so that the metal wiring layer can transmit large current to drive the Mini LED to work.

In the aspect of improving the display contrast of a large-size liquid crystal display, the most direct and most effective method is to perform partition control on the backlight of the LCD, that is, when a black picture needs to be displayed, the backlight of the area is turned off, so that the area can realize absolute black. In addition, the partitioning control of the backlight is also advantageous in HDR display.

In the experiment, the backlight source is divided into 600 areas, and each area is provided with 4 Mini LEDs, and 2400 Mini LEDs are used in total. The 4 Mini LEDs are two Mini LEDs which are connected in series to form 2 groups, the 2 groups are connected in parallel to form a partition, the partition distributed in a rectangle can be formed, the liquid crystal display is generally rectangular, the partition can more easily realize the distribution of a rectangular surface light source, the display effect of the liquid crystal display is better and uniform, the structure is better in favor of wiring, and the preparation difficulty is lower. The Mini LED backboard of the experiment adopts the blue light Mini LED to match with the QD film, so that the Mini LED has a better luminous effect. See table 2 for specific parameters in the experiment.

Table 2 table of various parameters in the experiment

Referring to table 2, the efficiency of the backlight source in the experiment can reach 93%, but the wiring area on the backlight source back plate only occupies 58% of the total area of the backlight source back plate, that is, the wiring layout on the backlight source back plate is simplified, compared with the related art in which the backlight is prepared on the PCB back plate, the wiring area occupation ratio is small, and meanwhile, the backlight is prepared on the backlight source back plate, and the thickness cost of the PCB does not need to be increased. Meanwhile, the thickness of the liquid crystal display cannot be increased under the condition of improving the display contrast of the liquid crystal display.

The metal routing layer in this experiment was a molybdenum niobium alloy/copper/molybdenum niobium alloy laminate, and the copper wire width shown in table 2 represents the width of the metal routing layer.

For the backlight backboard, the LED resistors with different distances from the driving circuit are different when the driving circuit is arranged on one side face of the backlight backboard, the resistor close to the driving circuit is a near-end resistor, the resistor far away from the driving circuit is a far-end resistor, and the driving circuit delay can be caused by the resistance difference.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A backlight backplane, characterized in that the backlight backplane (10) has a light-emitting area (101) and a binding area (102) located at the periphery of the light-emitting area (101);

the light-emitting region (101) is provided with a plurality of partitions (111), a group of LED pads (112) is arranged in each partition (111), a plurality of IC pads (121) are arranged in the binding region (102), the group of LED pads (112) comprises at least two LED pad pairs (113), each LED pad pair (113) comprises an LED anode pad (113A) and an LED cathode pad (113B), the IC pads (121) comprise a plurality of IC anode pads (121A) and a plurality of IC cathode pads (121B), and the number of the IC anode pads (121A) is greater than that of the IC cathode pads (121B);

each subarea (111) is connected with one IC anode bonding pad (121A) through one anode routing wire (114), and different subareas (111) are connected with different IC anode bonding pads (121A);

the partitions (111) in the same row are divided into at least two groups, each group of partitions (111) is connected with one IC cathode pad (121B) through one cathode routing line (115), the partitions (111) in different groups are connected with different IC cathode pads (121B), the partitions (111) belonging to the same group are arranged at intervals, and the partitions (111) belonging to different groups are periodically and alternately arranged.

2. The backlight backplane according to claim 1, wherein the set of LED pads (112) comprises at least two strings of LED pads (112), each string of LED pads (112) comprising at least two pairs (113) of LED pads;

at least two LED pad pairs (113) in the same LED pad (112) are sequentially connected in series, and in the two adjacent LED pad pairs (113), an LED anode pad (113A) of one LED pad pair (113) is connected with an LED cathode pad (113B) of the other LED pad pair (113);

in the same group of LED bonding pads (112), the LED anode bonding pad (113A) at one end of each string of the LED bonding pads (112) is connected with the anode wire (114), and the LED cathode bonding pad (113B) at the other end of each string of the LED bonding pads (112) is connected with the cathode wire (115).

3. The backlight backplane according to claim 1, wherein the plurality of the arrays of the segments (111) are distributed in the light emitting area (101), the number of rows of the segments (111) ranges between 30 and 60, and the number of columns of the segments (111) ranges between 10 and 20.

4. The backlight backplane according to any of the claims 1 to 3, wherein the backlight backplane (10) comprises a substrate (103), and a first insulating layer (104), a metal routing layer (105), a second insulating layer (106) and a pad layer (107) which are stacked on the substrate (103), wherein the LED pad pair (113) and the IC pad (121) are located on the pad layer (107), and wherein the anode trace (114) and the cathode trace (115) are located on the metal routing layer (105);

a via hole (161) is formed in the second insulating layer (106), and the pad layer (107) is connected with the metal wiring layer (105) through the via hole (161).

5. The backlight backplane according to claim 4, wherein at least one of the metal wiring layer (105) and the pad layer (107) is made of:

copper, molybdenum niobium alloy, or molybdenum niobium alloy/copper/molybdenum niobium alloy laminate.

6. The backlight backplane according to claim 4, wherein the thickness of the metal routing layer (105) ranges between 1.5 μm and 2.5 μm and the width of the metal routing layer (105) ranges between 0.3mm and 0.5 mm.

7. A backlight characterized in that it comprises a backlight backplane (10) according to any of claims 1 to 6, and micro light emitting diodes (20) bound to the backlight backplane (10).

8. A method for manufacturing a backlight backboard, wherein the method is used for manufacturing the backlight backboard (10) according to any one of claims 1 to 3, and the method for manufacturing the backlight backboard comprises the steps of:

manufacturing a first insulating layer (104) on a substrate (103);

manufacturing a metal routing layer (105) on the first insulating layer (104), wherein the anode routing (114) and the cathode routing (115) are located on the metal routing layer (105);

manufacturing a second insulating layer (106) on the metal wiring layer (105);

carrying out graphical processing on the second insulating layer (106) and manufacturing a through hole (161) connected with the metal wiring layer (105);

and manufacturing a pad layer (107) on the second insulating layer (106), wherein the LED pad pair (113) and the IC pad (121) are both positioned on the pad layer (107), and the pad layer (107) is connected with the metal routing layer (105) through the through hole (161).

9. A method for manufacturing a backlight source is characterized by comprising the following steps:

manufacturing the backlight backboard (10) by using the manufacturing method of the backlight backboard according to claim 8;

binding micro light emitting diodes (20) to the backlight backplane (10).