CN112164326B

CN112164326B - Display circuit board, manufacturing method thereof and LED display screen

Info

Publication number: CN112164326B
Application number: CN202010990249.7A
Authority: CN
Inventors: 熊周成; 胡小龙; 叶裕清
Original assignee: Individual
Current assignee: Xiong Zhoucheng
Priority date: 2020-09-18
Filing date: 2020-09-18
Publication date: 2021-07-13
Anticipated expiration: 2040-09-18
Also published as: CN112164326A

Abstract

The invention discloses a display circuit board, a manufacturing method thereof and an LED display screen, and belongs to the technical field of micro-space display screens. The circuit board comprises a glass substrate and a plurality of electronic elements arranged on the glass substrate; the glass substrate is provided with circuit layers on the front side and the back side, at least one of the circuit layers on the front side or the back side adopts a plurality of circuit layers, wherein insulating layers are arranged among the circuit layers of the plurality of circuit layers, and the insulating layers are provided with windows so as to realize the electric connection among the circuit layers and the electric connection between the circuit layers and electronic components; the electronic element comprises flip bare chip LED light-emitting chips and bare chip constant current driving chips which are arranged on the front surface of the glass substrate, wherein each bare chip constant current driving chip drives at least one flip bare chip LED light-emitting chip. By adopting the invention, the pixel point distance of the LED display screen can be effectively reduced, and the stability of the display image signal, the integration simplicity of the product construction process and the seamless splicing among the LED display units are realized.

Description

Display circuit board, manufacturing method thereof and LED display screen

Technical Field

The invention relates to the technical field of LED display screens, in particular to a display circuit board, a manufacturing method of the display circuit board and an LED display screen.

Background

With the development of the LED display screen technology, the micro-pitch LED (miniled) display screen gradually occupies an important position in the LED display screen technology industry due to its advantages of small pitch, clear display image, low power consumption, and the like. The LED display screen is formed by a plurality of display module assembly concatenations more, every display module assembly includes the PCB board and fixes at least one lamp plate on the PCB board and constitutes, be equipped with the LED lamp of a plurality of full-color RGB (red yellow blue three primary colors) on the lamp plate, every lamp plate all is equipped with an external constant current drive circuit board, connect through transmission cable and HUB board between this constant current drive circuit board and every display module assembly and realize receiving and transmission control signal, show with each display element of control and drive.

The LED display screen of the display module in the prior art is limited by the structure of the light collecting plate, has a heavy structure and low pixels, and cannot meet the requirements of people on lightness, thinness and high pixels of the LED display screen.

Disclosure of Invention

Technical problem to be solved

In view of the above disadvantages and shortcomings of the prior art, the invention provides a display circuit board, a manufacturing method thereof and an LED display screen, which solve the problems that the micro-space LED display screen in the prior art is limited by a lamp panel structure and has a heavy guide structure and low pixels.

(II) technical scheme

In order to achieve the purpose, the invention adopts the main technical scheme that:

in a first aspect, an embodiment of the present invention provides a display circuit board, which is suitable for a miniLED display screen, where the circuit board includes a glass substrate and a plurality of electronic components arranged on the glass substrate;

the glass substrate is characterized in that circuit layers are arranged on the front side and the back side of the glass substrate, at least one of the circuit layers on the front side or the back side adopts a plurality of circuit layers, insulating layers are arranged among the circuit layers of the plurality of circuit layers, and the insulating layers are provided with windows so as to realize the electric connection among the circuit layers and the electric connection between the circuit layers and electronic components;

the electronic element comprises flip bare chip LED light-emitting chips and bare chip constant current driving chips which are arranged on the front surface of the glass substrate, wherein each bare chip constant current driving chip drives at least one flip bare chip LED light-emitting chip.

Optionally, the glass substrate is further provided with a plurality of conductive holes, and the electronic component further includes a control component;

the control element is arranged on the back surface of the glass substrate;

and the circuit layers on the front surface and the back surface of the glass substrate and/or the circuit layers and the electronic elements are electrically connected through the conductive holes.

Optionally, the circuit layer is also provided with a window, the window of the circuit layer and the window of the insulating layer form a cross-layer window, and the pins of the electronic component are electrically connected with different circuit layers through the cross-layer window.

Optionally, the circuit layers are electrically connected by adopting a pressing manner.

Optionally, the glass substrate is a copper-clad glass substrate or a TFT glass substrate, and the circuit layer is a copper-clad circuit layer or an ITO film-coated circuit layer.

Optionally, a dynamic driving mode is adopted between the bare chip constant current driving chip and the flip bare chip LED light emitting chip.

Optionally, the bare-crystal constant-current driving chip is a row-column-in-one chip.

In a second aspect, an embodiment of the present invention provides an LED display screen, where the LED display screen includes at least two LED display units as described above, and glass substrates of two adjacent LED display units are connected in a cascade manner through a control element.

Preferably, the LED display screen is further provided with a power supply circuit for supplying power to each LED display unit.

In a third aspect, an embodiment of the present invention provides a method for manufacturing a display circuit board, where the display circuit board is suitable for an LED display screen, and the method includes:

a, arranging a conductive hole in a glass substrate, wherein a conductive material is arranged in the conductive hole;

step B, alternately arranging circuit layers and insulating layers on the glass substrate in sequence from the surface of the glass substrate, so that a plurality of circuit layers are arranged on the glass substrate and are separated by the insulating layers;

wherein the step of providing the circuit layer comprises:

c1, laying a layer to be etched on the surface of the glass substrate or the insulating layer, etching and windowing the layer to be etched to form a circuit layer, wherein the layer to be etched is an ITO (indium tin oxide) coating film or a copper foil film;

c2, electrically connecting the circuit layer currently being processed with the conductive hole and/or the finished circuit layer by using the finished circuit layer and the window of the insulating layer;

the step of providing an insulating layer includes:

d1, laying an insulating layer on the circuit layer, and windowing the insulating layer.

(III) advantageous effects

The invention has the beneficial effects that:

1. the LED display unit adopts unpackaged flip bare chip LED light-emitting chips and bare chip constant current driving chips, and one bare chip constant current driving chip drives a plurality of flip bare chip LED light-emitting chips, so that the pixel point spacing of the LED display unit is effectively reduced, the problems of current drop and signal attenuation can be effectively solved, and the stability of image signal display is improved;

2. the control element is not connected with the bare-crystal constant-current driving chip through a transmission cable, when the LED display screen is assembled by a plurality of LED display units, the control element on the back of the glass substrate is only required to be cascaded, so that the integration simplicity of the product construction process is realized, the seamless splicing among the LED display units is favorably realized, and the thickness and the weight of the LED display units are effectively reduced;

3. the front and the back of the glass substrate are both provided with the film coating circuits, the flip bare-chip LED light-emitting chip and the bare-chip constant current driving chip are simultaneously arranged on the front of the glass substrate and are electrically connected with the film coating circuits, and the control element is arranged on the back of the glass substrate, so that the glass substrate only needs to drill a small number of holes to connect the film coating circuits on the front and the back, and the number of holes drilled on the glass substrate is effectively reduced;

4. an ITO film coating circuit or a copper-clad circuit is adopted, so that the circuit precision is high, and the method is more suitable for the production process of the LED display screen with micro-spacing (particularly, the spacing between pixel points is less than 0.9 mm);

5. the current characteristic of the flip bare chip LED light-emitting chip is completely matched by adopting a dynamic (PWM) driving mode, and the improvement is carried out on the basis of the existing light-emitting chip, so that the requirement of the flip bare chip LED light-emitting chip on the current saturation is completely met;

6. the pixel point interval is smaller, and the mass transfer technology is easier to realize.

Drawings

Fig. 1 is a schematic structural diagram of a display circuit board according to embodiment 1 of the present invention;

FIG. 2 is a schematic diagram showing electrical connections between circuit layers of multiple layers of a circuit board and between the multiple circuit layers and an electronic component;

FIG. 3 is a schematic diagram of circuit layer wiring;

fig. 4 is a schematic circuit diagram of a bare chip constant current driving chip driving a plurality of flip bare chip LED light emitting chips;

FIG. 5 is a schematic diagram of connections between multiple bare die constant current driver chip drivers;

fig. 6 is a schematic structural diagram of a module of an LED display screen according to a second embodiment of the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings. Where directional terms such as "upper", "lower", "left", "right", etc. are used herein with reference to the orientation of fig. 1.

The display circuit board provided by the invention comprises a glass substrate and a plurality of electronic elements arranged on the glass substrate;

In practical application, the glass substrate may be a copper-clad glass substrate or a TFT glass substrate, and the circuit layer may be a copper-clad circuit layer or an ITO-coated circuit layer.

The LED display unit adopts the unpackaged flip bare chip LED light-emitting chips and the bare chip constant current driving chips, and one bare chip constant current driving chip drives a plurality of flip bare chip LED light-emitting chips, so that the pixel point distance of the LED display unit is effectively reduced; and the control element is connected with the bare crystal constant current driving chip without a transmission cable, so that the thickness and the weight of the LED display unit are effectively reduced.

In order to better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Detailed description of the preferred embodimentsthe detailed description section.

Example 1:

the embodiment of the invention provides a display circuit board. Referring to fig. 1 to 3, the display circuit board includes a glass substrate 10, a plurality of flip-chip bare-chip LED light emitting chips 20, a plurality of bare-chip constant current driving chips 30, and a control device 40.

The glass substrate 10 may be a TFT glass substrate having a thickness of 0.3mm to 2.0mm, and the front surface thereof is sequentially provided with a first circuit layer 111, an intermediate insulating layer 112, a second circuit layer 113, and a first surface insulating layer 114. The third circuit layer 121 and the second surface insulating layer 122 are disposed on the back surface of the glass substrate 10.

In practical application, the thickness of the insulating layer is about 0.1um-10um, and the thickness of the circuit layer is about 1um-35 um.

The glass substrate 10 is further provided with a plurality of conductive vias (e.g., a first conductive via 131, a second conductive via 132, and a third conductive via 133), and the circuit layers on the front and back sides of the glass substrate 10 or the electronic components and the circuit layers are electrically connected through the conductive vias.

In practical applications, a conductive material or a conductive coating may be poured into the conductive holes to electrically connect the circuit layers on the front and back sides of the glass substrate 10.

The first circuit layer 111, the intermediate insulating layer 112, the second circuit layer 113, and the first surface insulating layer 114 are provided with windows, so that a cross-layer window can be formed between the first circuit layer 111 and the second circuit layer 113.

As shown in fig. 2, when the opening window of the first surface insulating layer 114 is not overlapped with the opening window of the second circuit layer 113, the pad 1131 of the second circuit layer is exposed, and when the opening windows of the first surface insulating layer 114 and the second circuit layer 113 are overlapped, the pad 1111 on the first circuit layer 111 is exposed, at this time, the pin 21 of the flip-chip bare-crystal LED light emitting chip 20 is welded on the pad 1111 of the first circuit layer, and the pin 22 is welded on the pad 1131 of the second circuit layer, thereby realizing the cross-layer welding. Similarly, through the opening of the circuit layers and the insulating layer, the conductive holes of the glass substrate 10 can also achieve electrical connection between different circuit layers and between electronic components and the circuit layers, for example, the first conductive hole 131 electrically connects the first circuit layer 111 and the third circuit layer 121, the second conductive hole 132 electrically connects the second circuit layer 113 and the third circuit layer 121, and the third conductive hole 133 electrically connects the first circuit layer 111 and the electronic component 123 disposed on the back surface of the glass substrate 10.

In practical application, if a plurality of circuit layers are also arranged on the back surface of the glass substrate, an insulating layer is also arranged between the circuit layers, and cross-layer windowing can be realized between the circuit layers and the insulating layer in a windowing manner.

In practical applications, the conductive via may electrically connect any one of the circuit layers on the front and back sides of the glass substrate 10.

In practical application, the first circuit layer 111 and the second circuit layer 113 are RGB driving circuits, and are used for driving the flip bare-chip LED light-emitting chip 20 to emit light; the third circuit layer 121 includes a control circuit and a power supply circuit, wherein the control circuit is connected to the control element 40 and the RGB driving circuit, and the power supply circuit is used to supply power to the control element 40, the flip bare LED light emitting chip 20, and the bare constant current driving chip 30.

In practical applications, the circuit layers and the electronic components can be electrically connected by pressing, as shown in fig. 3, a position of a circular point in the figure is a pressing point of the circuit layer.

The flip bare LED light emitting chip 20 and the bare constant current driving chip 30 are disposed on the front surface of the glass substrate 10 and electrically connected to the first circuit layer 111 and/or the second circuit layer 113.

The control element 40 is provided on the back surface of the glass substrate 110 and electrically connected to the power supply circuit and the control circuit on the back surface.

The control element 40 can receive the signal sent by the control circuit, process the signal and send the processed signal to the bare chip constant current driving chip 30 of the display circuit board, and the control element of the next display circuit board adjacent to the bare chip constant current driving chip.

In practical applications, the control element 40 may be a signal control chip or a signal control circuit.

In practical applications, one bare chip constant current driving chip 30 can drive at least 1 flip bare chip LED light emitting chip 20. The bare-chip constant current driving chip 30 may be a "line and row integrated" chip. The flip bare LED light emitting chip 20 can be connected to the RGB circuit by a common anode scheme or connected to the RGB driving circuit by a common cathode scheme.

Each flip bare chip LED light emitting chip 20 includes a red chip R, a green chip G, and a blue chip B, and each flip bare chip LED light emitting chip constitutes a pixel point.

The flip bare chip LED light-emitting chips 20 and the bare chip constant current driving chips 30 on the glass substrate are arranged in a matrix, and the dot spacing between each pixel point can reach 0.2mm to 2.0 mm.

In practical application, a dynamic driving mode can be adopted between the output pin of the bare chip constant current driving chip 30 and the flip bare chip LED light emitting chip 20.

The plurality of bare chip constant current driver chips 20 may be connected in a cascade manner, please refer to fig. 4 and 5, which are schematic circuit diagrams of the circuit in which each bare chip constant current driver chip drives a plurality of flip chip bare chip LED light emitting chips, respectively.

As shown in fig. 4, each die constant current driver chip 30 drives a plurality of flip die LED light emitting chips 20. Each bare chip constant current driving chip is provided with a plurality of groups of LED control output pins, a pair of data input/output pins SDI/SDO, a pair of clock signal input/output pins CLKI/CLKO and four signal output pins H1\ H2\ H3\ H4. The LED control output pins comprise a pin R, a pin G and a pin B, which are respectively connected with a red wafer, a green wafer and a blue wafer of the flip bare chip LED light-emitting chip, and meanwhile, the four signal output pins H1\ H2\ H3\ H4 are also connected with the flip bare chip LED light-emitting chip 20 and are used for acquiring control signals of the red wafer, the green wafer and the blue wafer.

As shown in fig. 5, a data input pin SDI of a first bare chip constant current driving chip is configured to receive a data signal provided by a control element, and a clock signal input pin CLKI is configured to receive a clock signal provided by the control element. A data input pin SDI and a clock signal input pin CLKI of each bare chip constant current driving chip behind the first bare chip constant current driving chip are respectively connected with a data output pin SDO and a clock signal output pin CLKO of the previous bare chip constant current driving chip, and the data output pin SDO and the clock signal output pin CLKO are respectively connected with a data input pin SDI and a clock signal output pin CLKI of the next bare chip constant current driving chip 30, so that the cascade connection among a plurality of bare chip constant current driving chips is realized.

On the basis of the foregoing embodiments, a second embodiment of the present invention provides an LED display screen, please refer to fig. 6, in which the LED display screen includes a control circuit 510, at least two display circuit boards 520, and a power supply circuit 530.

The display circuit board 520 is the display circuit board according to the first embodiment, and is not described herein.

The end faces of the glass substrates between the display circuit boards 520 are spliced together, and seamless splicing can be achieved.

The control circuit 510 is used to control each display board 520, and is communicatively connected to the control elements of the first display board 520.

The control elements of the adjacent display circuit boards are in cascade connection to transmit signals, and seamless splicing is facilitated.

And a power supply circuit 530 for supplying power to each display circuit board 520.

In practical application, signals can be transmitted between the control circuit and the control element of the first display circuit board and between the control elements of the adjacent display circuit boards through wireless signals.

The third embodiment of the invention provides a manufacturing method of a display circuit board, which comprises the following steps:

wherein the step of providing the circuit layer comprises:

the step of providing an insulating layer includes:

In practical applications, the conductive hole may be perforated nearby (for example, an electrical connection point for supplying power to the bare die constant current driver chip from the power supply circuit may be disposed near a pin of the VCC of the bare die constant current driver chip) to reduce a distance between the power supply line and the signal line.

In practical application, a layer of ITO film can be coated on the glass substrate by utilizing methods such as magnetron sputtering, spraying, vacuum evaporation, chemical vapor deposition, reflection ion implantation and the like.

In practical application, windows can be arranged on each circuit layer and the insulating layer to realize cross-layer electrical connection between different circuit layers or between an electrical element and different circuit layers.

In practical application, each circuit layer can be electrically connected through a pressing method.

In practical application, after the step B, the method further comprises the following steps:

and welding the electrical components on the corresponding circuit layers.

The LED display unit and the LED display screen provided by the embodiment of the invention have the following advantages:

1. the unpackaged flip bare chip LED light-emitting chips and bare chip constant current driving chips are adopted, and one bare chip constant current driving chip drives a plurality of flip bare chip LED light-emitting chips, so that the dot spacing between light-emitting point pixels is effectively reduced;

2. the front and the back of the glass substrate are both provided with the film coating circuits, the flip bare-chip LED light-emitting chip and the bare-chip constant current driving chip are simultaneously arranged on the front of the glass substrate and are electrically connected with the film coating circuits, and the control element is arranged on the back of the glass substrate, so that the glass substrate only needs to drill a small number of holes to connect the film coating circuits on the front and the back, and the number of holes drilled on the glass substrate is effectively reduced;

3. the control element and the bare-crystal constant-current driving chip are not connected through a transmission cable, when the LED display screen is assembled by the LED display units, the control element on the back of the glass substrate is only required to be cascaded, and seamless splicing among the LED display units is achieved.

4. An ITO film coating circuit is adopted, so that the circuit precision is high, and the method is more suitable for the production process of the micro-space LED display screen;

5. the flip bare chip LED light-emitting chips are respectively driven by the driving chips, so that the problems of current drop and signal attenuation are effectively solved;

6. a static (AM) driving mode is adopted, so that the comfort of human eyes is better met, and the problem of line-by-line flicker of images driven by dynamic scanning (PM) is avoided;

7. the pixel point interval is smaller, and the mass transfer technology is easier to realize.

In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium; either as communication within the two elements or as an interactive relationship of the two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, a first feature may be "on" or "under" a second feature, and the first and second features may be in direct contact, or the first and second features may be in indirect contact via an intermediate. Also, a first feature "on," "above," and "over" a second feature may be directly or obliquely above the second feature, or simply mean that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lower level than the second feature.

In the description herein, the description of the terms "one embodiment," "some embodiments," "an embodiment," "an example," "a specific example" or "some examples" or the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are illustrative and not restrictive, and that those skilled in the art may make changes, modifications, substitutions and alterations to the above embodiments without departing from the scope of the present invention.

Claims

1. A display circuit board is suitable for a micro-space display screen and is characterized by comprising a glass substrate and a plurality of electronic elements arranged on the glass substrate;

each circuit layer of the multilayer circuit layers is also provided with a window, the window of each circuit layer and the window of the insulating layer form a cross-layer window, a bonding pad on each circuit layer is exposed out of the window, and pins of the electronic components are welded with bonding pads on different circuit layers through the cross-layer window to realize the electric connection of the electronic components and different circuit layers;

the electronic component comprises flip bare chip LED light-emitting chips and bare chip constant current driving chips which are arranged on the front surface of the glass substrate, wherein each bare chip constant current driving chip drives at least one flip bare chip LED light-emitting chip.

2. The display circuit board of claim 1, wherein the glass substrate further has a plurality of conductive vias formed therein, and the electronic component further comprises a control component;

the control element is arranged on the back surface of the glass substrate;

3. The display circuit board of claim 2, wherein the electrical connection between the circuit layers of the multi-layer circuit layer is achieved by pressing.

4. The display circuit board of claim 3, wherein the glass substrate is a copper-clad glass substrate or a TFT glass substrate, and the circuit layer is a copper-clad circuit layer or an ITO film-coated circuit layer.

5. The display circuit board of claim 4, wherein a dynamic driving manner is employed between the die constant current driving chip and the flip die LED light emitting chip.

6. The display circuit board of claim 1, wherein the bare chip constant current driving chip is a row-column-in-one chip.

7. An LED display screen, characterized in that the LED display screen comprises at least two display circuit boards according to any one of claims 1 to 6;

two adjacent display circuit boards are connected in a cascade mode through the control element.

8. The LED display screen of claim 7, wherein the LED display screen is further provided with a power supply circuit for supplying power to each display circuit board.

9. A method of manufacturing a display circuit board according to any one of claims 1 to 6, the display circuit board being adapted for use in an LED display screen, the method comprising:

step B, alternately arranging circuit layers and insulating layers on the glass substrate from the surface in sequence, so that a plurality of circuit layers are arranged on the glass substrate and are separated by the insulating layers;

wherein the step of providing the circuit layer comprises:

the step of providing an insulating layer includes: