CN118280276A - LED display panel and manufacturing process thereof - Google Patents

Abstract

The invention discloses an LED display panel and a manufacturing process thereof, wherein the LED display panel comprises a circuit board and a plurality of pixel components, a plurality of pixel installation positions which are distributed at intervals are arranged on a display surface of the circuit board, and each pixel installation position is provided with an anode bonding pad, a cathode bonding pad, a data input bonding pad and at least three driving output bonding pads; and each pixel component comprises a driving IC and at least three light emitting chips, wherein the driving IC is respectively and electrically connected with the positive electrode pad, the negative electrode pad, the data input pad and the at least three driving output pads, and the light emitting chips are respectively and electrically connected with the positive electrode pad and the corresponding driving output pads. According to the technical scheme, the driving IC and the light-emitting chip are arranged on the same surface of the circuit board, meanwhile, the driving IC and the light-emitting chip are both in a flip-chip welding process, so that the production efficiency can be improved, the thickness of a product can be reduced, and the permeability of the product can be improved by adopting the transparent circuit board.

Description

LED display panel and manufacturing process thereof

Technical Field

The invention relates to the technical field of LED display panels, in particular to an LED display panel and a manufacturing process thereof.

Background

Along with the rapid development of information technology and display technology, the LED display panel has the advantages of high brightness, long service life, energy conservation, environmental protection and the like, and is widely applied to a plurality of fields such as advertisements, public information display, stage background and the like.

The traditional LED display panel adopts the mode of front surface mounting LED lamp beads and back surface mounting driving ICs, the design ensures that the LED lamp beads and the driving ICs are distributed on two sides of the display panel, the overall thickness of the display panel is increased, the flexibility of product design is limited, circuits on two sides of the display panel are required to be designed and connected, the overall circuit arrangement is complex, the layout of the circuits is realized by a plurality of layers of circuit boards, the manufacturing cost is improved, in addition, the separated design also needs to be respectively pasted on two sides of the display panel, the production difficulty is increased, and the production efficiency is reduced. In view of this, there is a need for improvements therein by those skilled in the art.

Disclosure of Invention

The invention mainly aims to provide an LED display panel, which aims to solve the technical problems of low production efficiency, high product thickness and the like caused by the fact that lamp beads and drive ICs of the display panel in the prior art are respectively arranged on two sides of the display panel.

In order to achieve the above purpose, the LED display panel provided by the present invention comprises a circuit board and a plurality of pixel components, wherein the circuit board comprises a display surface, a plurality of pixel installation positions are arranged on the display surface, the pixel installation positions are distributed at intervals, and each pixel installation position is provided with a positive electrode bonding pad, a negative electrode bonding pad, a data input bonding pad and at least three driving output bonding pads; the pixel assembly is arranged in one pixel installation position, each pixel assembly comprises a driving IC and at least three light emitting chips, the driving IC is respectively and electrically connected with the positive electrode bonding pad, the negative electrode bonding pad, the data input bonding pad and the at least three driving output bonding pads, the number of the at least three light emitting chips is the same as and corresponds to the number of the at least three driving output bonding pads one by one, and the light emitting chips are respectively and electrically connected with the positive electrode bonding pads and the corresponding driving output bonding pads.

Optionally, the positive electrode bonding pad includes positive electrode vertical extension portion, positive electrode vertical extension portion extends in first direction, at least three drive output bonding pads all are located positive electrode vertical extension portion's same side, at least three drive output bonding pads set up in parallel to the interval distribution is in first direction.

Optionally, the data input pad extends in the first direction, the data input pad and the positive vertical extension portion are arranged at intervals, and all the driving output pads are arranged between the data input pad and the positive vertical extension portion.

Optionally, each of the driving output pads extends in a second direction, and the second direction is perpendicular to the first direction.

Optionally, the positive electrode pad includes a first positive electrode lateral extension portion, the first positive electrode lateral extension portion with the positive electrode vertical extension portion is connected, the negative electrode pad includes a first negative electrode lateral extension portion, the first positive electrode lateral extension portion with the first negative electrode lateral extension portion all extends in the second direction, the second direction with the first direction is mutually perpendicular, the partial structure of the first positive electrode lateral extension portion with the parallel and interval setting of first negative electrode lateral extension portion, data input pad and whole drive output pad all are located between the first positive electrode lateral extension portion with the first negative electrode lateral extension portion.

Optionally, a part of the pixel mounting positions in the plurality of pixel mounting positions are arranged in a column in the second direction;

The positive electrode bonding pad further comprises a second positive electrode transverse extension part, the second positive electrode transverse extension part extends in the second direction, the second positive electrode transverse extension part is arranged on one side of the first positive electrode transverse extension part, which is opposite to the first negative electrode transverse extension part, and is connected with the first positive electrode transverse extension part, and a plurality of second positive electrode transverse extension parts positioned in the same column are connected into a whole;

the negative electrode bonding pad further comprises a second negative electrode transverse extension part, the second negative electrode transverse extension part extends in the second direction, the second negative electrode transverse extension part is arranged on one side of the first negative electrode transverse extension part, which is opposite to the first positive electrode transverse extension part, and is connected with the first negative electrode transverse extension part, and a plurality of second negative electrode transverse extension parts which are located in the same row are connected into a whole.

Optionally, a packaging adhesive is disposed on the display surface, and the packaging adhesive is capable of transmitting light and wrapping all the driving ICs and all the light emitting chips.

Optionally, the material of the circuit board is transparent.

The invention also provides a manufacturing process of the LED display panel, which comprises the following steps:

s1, etching an anode bonding pad, a cathode bonding pad, a data input bonding pad and three driving output bonding pads on each pixel installation position of a circuit board;

S2, detecting whether each bonding pad on the circuit board is complete or not through the AOI equipment, if not, re-executing the step S1 on the circuit board, and if yes, executing the next step;

S3, silk-screen printing solder paste or conductive adhesive on the circuit board;

S4, detecting whether each solder paste or conductive adhesive on the circuit board is complete or not through an AOI device, if not, re-executing the step S3 on the circuit board, and if so, executing the next step;

s5, welding a driving IC and a light-emitting chip at a bonding pad position corresponding to the circuit board;

S6, detecting whether each driving IC and each light emitting chip on the circuit board are complete or not through an AOI device, if not, re-executing the step S5 on the circuit board, and if so, executing the next step;

And S7, performing reflow soldering or high-temperature soldering on the circuit board, and powering up to test whether the LED display panel is normal.

The LED display panel of the technical scheme of the invention has the following advantages:

The inverted mounting of the driving IC and the light emitting chip on the same surface of the circuit board simplifies the circuit design of the circuit board, and the conventional LED display panel generally requires mounting the driving IC and the light emitting chip on both sides of the circuit board, which increases not only the complexity of the circuit design and wiring, but also the overall impedance of the circuit and the time of signal propagation. In the new design, because the driving IC and the light emitting chip of the same pixel are positioned on the same surface of the circuit board, a shorter connecting wire can be used for directly and electrically connecting, so that the impedance of the circuit is reduced, the signal transmission efficiency is obviously improved, and the response speed of display and the stability of the signal are enhanced.

In addition, the single-sided inverted layout reduces the number of layers of the circuit board, thereby reducing the material use and production cost, reducing the number of layers, simultaneously only concentrating the elements on one side, reducing the technical difficulty in the production process and the dependence on precision equipment, further improving the production efficiency and the expandability of production, and being particularly beneficial to mass production because the method can obviously shorten the time from production to market and has important commercial value for rapidly changing electronic markets.

In maintenance and service aspects, the configuration of single-sided flip-chip enables all key components such as the driving IC and the light emitting chip to be easily accessed and replaced, so that maintenance work is greatly simplified, and maintenance cost is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an embodiment of an LED display panel according to the present invention;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

FIG. 3 is a schematic view of the structure of FIG. 1 with the pixel assembly omitted;

FIG. 4 is a partial enlarged view at B in FIG. 3;

fig. 5 is a schematic diagram of the structure of the driving IC and the light emitting chip;

FIG. 6 is a cross-sectional view of the LED display panel of FIG. 1 after placement of the encapsulant;

Fig. 7 is a schematic structural diagram of an embodiment of a manufacturing process of an LED display panel according to the present invention.

Reference numerals illustrate:

1. A circuit board; 11. a display surface; 12. a pixel mounting location; 13. a positive electrode pad; 131. a positive electrode vertical extension; 132. a first positive electrode lateral extension; 133. a second positive electrode lateral extension; 14. a negative electrode pad; 141. a first negative electrode lateral extension; 142. a second negative electrode lateral extension; 15. a data input pad; 16. driving the output pad; 2. a pixel assembly; 21. a driving IC; 22. a light emitting chip; 3. and (5) packaging glue.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and rear … …) are included in the embodiments of the present invention, the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.

Furthermore, the description of "first," "second," etc. in this disclosure is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, "and/or" throughout this document includes three schemes, taking a and/or B as an example, including a technical scheme, a technical scheme B, and a technical scheme that both a and B satisfy; in addition, the technical solutions of the embodiments may be combined with each other, and it is necessary to base that the technical solutions can be implemented by those skilled in the art, and when the technical solutions are contradictory or cannot be implemented, it should be considered that the combination of the technical solutions does not exist and is not within the scope of protection claimed by the present invention.

The invention provides an LED display panel.

In the embodiment of the invention, as shown in fig. 1 to 6, the LED display panel comprises a circuit board 1 and a plurality of pixel components 2, the circuit board 1 comprises a display surface 11, a plurality of pixel mounting positions 12 are arranged on the display surface 11, the plurality of pixel mounting positions 12 are distributed at intervals, and each pixel mounting position 12 is provided with a positive electrode bonding pad 13, a negative electrode bonding pad 14, a data input bonding pad 15 and at least three driving output bonding pads 16; one pixel assembly 2 is disposed in one pixel mounting position 12, each pixel assembly 2 includes a driving IC21 and at least three light emitting chips 22, the driving IC21 is electrically connected with the positive electrode pad 13, the negative electrode pad 14, the data input pad 15 and the at least three driving output pads 16, the number of the at least three light emitting chips 22 is the same as and one-to-one corresponding to the number of the at least three driving output pads 16, and the light emitting chips 22 are electrically connected with the positive electrode pad 13 and the corresponding driving output pads 16.

Specifically, the display surface 11 is a surface of the circuit board 1, and is used for mounting the driving IC21, the light emitting chip 22, and the like, and the pixel mounting positions 12 are predetermined positions on the display surface 11 of the circuit board 1, and one pixel mounting position 12 is used for mounting one pixel component 2, so as to realize the function of a pixel point.

The pad groups (positive electrode pad 13, negative electrode pad 14, data input pad 15, and drive output pad 16) are used to supply power (positive electrode and negative electrode), data signal input (data input pad 15), and output (drive output pad 16) to the drive IC21 and the light emitting chip 22, respectively.

The electrical connection between the driving IC21 and the light emitting chips 22 may be realized by a soldering technique, where each output end of the driving IC21 is connected to a corresponding driving output pad 16, and the positive electrode of the light emitting chip 22 is connected to the positive electrode pad 13 and the negative electrode of the light emitting chip 22 is connected to the corresponding driving output pad 16, so that the three light emitting chips 22 of the same pixel point are connected in parallel, and each light emitting chip 22 can be controlled independently and emit a light signal.

It will be appreciated that the inverted mounting of the driving IC21 and the light emitting chip 22 on the same surface of the wiring board 1 simplifies the circuit design of the wiring board 1, and the conventional LED display panel generally requires mounting the driving IC21 and the light emitting chip 22 on both sides of the wiring board 1, which increases not only the complexity of the wiring design and wiring, but also the overall impedance of the circuit and the time of signal propagation. In the new design, since the driving IC21 and the light emitting chip 22 of the same pixel are both located on the same surface of the circuit board 1, a shorter connecting wire can be used for direct electrical connection, so that not only is the impedance of the circuit reduced, but also the signal transmission efficiency is remarkably improved, and the response speed of display and the stability of the signal are enhanced.

In addition, the single-sided inverted layout reduces the number of layers of the circuit board 1, thereby reducing the material use and production cost, reducing the number of layers, simultaneously reducing the technical difficulty in the production process and the dependence on precision equipment because the elements are concentrated on one side, further improving the production efficiency and the expandability of production, and being particularly beneficial to mass production because the time from production to market can be obviously shortened, and having important commercial value for rapidly changing electronic markets.

In terms of maintenance and service, the configuration of single-sided flip-chip makes all key components such as the driving IC21 and the light emitting chip 22 easy to access and replace, greatly simplifies maintenance work, and reduces maintenance cost.

Referring to fig. 4, the positive electrode pad 13 includes a positive electrode vertical extension portion 131, the positive electrode vertical extension portion 131 extends in a first direction, at least three driving output pads 16 are all disposed on the same side of the positive electrode vertical extension portion 131, and at least three driving output pads 16 are disposed in parallel and are distributed at intervals in the first direction.

Since all the light emitting chips 22 in the same pixel mounting location 12 share one positive electrode pad 13 and the respective independent driving output pads 16 are arranged on the same side of the extension of the positive electrode pad 13, this configuration effectively reduces the transmission distance of the power supply to each light emitting chip 22, thereby reducing voltage drop and resistance loss. Reducing the voltage drop means that each light emitting chip 22 can obtain a more stable power supply, enhancing the brightness uniformity and color uniformity of the display, which is important to enhance the visual effect of the entire display panel.

The spaced and parallel arrangement of the drive output pads 16 reduces electromagnetic interference between adjacent light emitting chips 22, particularly during high frequency signal transmission, and this arrangement can effectively prevent signal crosstalk, ensure that each pixel can accurately respond to an input signal, and improve definition and dynamic expressive power of images. The pad layout is also beneficial to the thermal management of the circuit board 1, and the corresponding heat generation is reduced due to the reduction of resistance loss, so that the operation temperature of the light emitting chip 22 is maintained, and the service life of the display panel is prolonged.

Referring to fig. 4, the data input pad 15 extends in the first direction, the data input pad 15 and the positive vertical extension 131 are disposed at intervals, and all the driving output pads 16 are disposed between the data input pad 15 and the positive vertical extension 131.

Because the data input pads 15 extend in the first direction and are spaced apart from the vertical positive extension 131, the design not only physically separates the power supply from the signal and reduces electrical interference, but also installs all the driving output pads 16 in the same pixel installation site 12 on the same side of the data input pads 15, thus reducing the complex wiring requirements, reducing the overall cost of the circuit board 1, and simultaneously making the later maintenance simpler.

Referring to fig. 4, each of the driving output pads 16 extends in a second direction, which is perpendicular to the first direction. As will be appreciated, since the driving output pads 16 extend in the second direction, they can be compactly arranged in a space parallel to the data input pads 15, the first positive electrode vertical extensions 131, reducing an increase in circuit length due to an excessively wide pad pitch (the pitch of the data input pads 15 and the driving output pads 16, and the pitch of the driving output pads 16 and the first positive electrode vertical extensions 131), thereby reducing resistance and voltage loss.

Referring to fig. 4, the positive electrode pad 13 includes a first positive electrode lateral extension 132, the first positive electrode lateral extension 132 is connected to the positive electrode vertical extension 131, the negative electrode pad 14 includes a first negative electrode lateral extension 141, the first positive electrode lateral extension 132 and the first negative electrode lateral extension 141 both extend in a second direction, the second direction is perpendicular to the first direction, a part of the structure of the first positive electrode lateral extension 132 is parallel to and spaced apart from the first negative electrode lateral extension 141, and the data input pad 15 and all the driving output pads 16 are disposed between the first positive electrode lateral extension 132 and the first negative electrode lateral extension 141.

It will be appreciated that the regular pad arrangement simplifies the design and layout of the circuit, making the production process more efficient, reducing production errors and costs, and facilitating future maintenance and overhaul work.

Referring to fig. 1 and 3, a part of the pixel mounting bits 12 of the plurality of pixel mounting bits 12 are arranged in a column in the second direction;

The positive electrode pad 13 further includes a second positive electrode lateral extension portion 133, where the second positive electrode lateral extension portion 133 extends in the second direction, and the second positive electrode lateral extension portion 133 is disposed on a side of the first positive electrode lateral extension portion 132 opposite to the first negative electrode lateral extension portion 141, and is connected to the first positive electrode lateral extension portion 132, and a plurality of second positive electrode lateral extension portions 133 located in the same column are connected as a whole;

The negative electrode pad 14 further includes a second negative electrode lateral extension portion 142, where the second negative electrode lateral extension portion 142 extends in the second direction, and the second negative electrode lateral extension portion 142 is disposed on a side of the first negative electrode lateral extension portion 141 opposite to the first positive electrode lateral extension portion 132, and is connected to the first negative electrode lateral extension portion 141, and a plurality of second negative electrode lateral extension portions 142 located in the same column are connected as a whole.

By connecting the pixels in the same column in parallel, it is possible to ensure uniform distribution of power supply in the column, and each pixel point can obtain stable and uniform voltage and current, so that the pixels in the same column can maintain display uniformity and prevent uneven brightness.

In addition, in the parallel circuit configuration, the faults of the single pixels can not directly influence the functions of the whole row of pixels, so that the overall reliability of the panel is greatly improved, and the maintenance frequency and the cost are reduced.

Referring to fig. 6, the display surface 11 is provided with a packaging adhesive 3, and the packaging adhesive 3 is capable of transmitting light and is arranged to encapsulate all the driving ICs 21 and all the light emitting chips 22.

In practice, the encapsulant 3 is typically made of a high light transmittance material such as silicone.

It will be appreciated that the fully covered layer of the encapsulation glue 3 can effectively isolate dust, moisture and other environmental factors that may cause degradation of electronic components, and in addition, the physical protection layer provided by the encapsulation glue 3 also helps to resist external mechanical impact or pressure, reduce risk of damage, and prolong the service life of the LED display panel.

By means of the uniform encapsulation glue 3, the thermal energy can be dispersed in a wider area, reducing the problem of local overheating.

Optionally, the material of the circuit board 1 is a transparent material.

In particular, the transparent material may be a transparent Polycarbonate (PC), polymethyl methacrylate (PMMA), or the like.

The use of the circuit board 1 of transparent material can make the display panel look like ordinary transparent glass or plastic when not displaying light information, which is particularly useful for designing applications such as vehicle information display that require aesthetic or visual permeability.

The invention also provides a manufacturing process of the LED display panel, referring to fig. 7, the manufacturing process of the LED display panel is used for manufacturing the LED display panel, and the specific structure of the LED display panel refers to the above embodiment. The manufacturing process of the LED display panel comprises the following steps:

s1, etching an anode bonding pad, a cathode bonding pad, a data input bonding pad and three driving output bonding pads on each pixel installation position of a circuit board;

Specifically, etching is the removal of material from selected areas by chemical or physical means to form the desired pad structures that provide the necessary electrical connection points for subsequent component mounting (e.g., driver ICs and light emitting chips).

S2, detecting whether each bonding pad on the circuit board is complete or not through the AOI equipment, if not, re-executing the step S1 on the circuit board, and if yes, executing the next step;

This test is to verify that the shape, size and location of the pads accurately meet design requirements. The AOI equipment captures the image of the bonding pads through a high-resolution camera system and compares the image with a preset standard to ensure that each bonding pad is not damaged and correct, and if the bonding pads are found to be defective, the step S1 is repeated for correction to ensure that the quality of all the bonding pads reach the standard, thereby laying a foundation for high-quality electronic connection.

Specifically, step S2 includes the steps of:

S21, acquiring image data of a circuit board to obtain original image data;

The step is to fix the circuit board on a scanning platform of the AOI device, correct the position of the circuit board by using a positioning system, ensure that the scanning covers all the bonding pad areas, start the AOI device, gradually scan from one end of the circuit board to the other end, and capture high-resolution images of the bonding pads row by row.

S22, preprocessing the original image data to obtain first image data, wherein the preprocessing comprises denoising and contrast enhancement;

specifically, the bilateral filtering formula adopted in the denoising process is as follows:

。

Wherein the method comprises the steps of Is the original image of the object to be imaged,Is a filtered image of the object to be processed,Is a spatial kernel which is used for the processing of the data,AndStandard deviations of the spatial domain and the range domain, respectively.

The contrast enhancement process uses the following formula:

。

Wherein the method comprises the steps of Is an image of the object after enhancement,AndIs a parameter for adjusting contrast and brightness, and min is a minimum pixel value of an image.

Assuming that the image size of a circuit board is 1000x1000 pixels, the pad region contains slight ambient noise and insufficient contrast, first, the above bilateral filtering formula is applied to selectDenoising, namely, using a linear stretching contrast enhancement method to setThe contrast of the pad with the background is enhanced.

The processing method not only clearly highlights the edge of the bonding pad, but also improves the visual effect of the whole image, so that the subsequent bonding pad detection and quality evaluation are more accurate and efficient, and a solid foundation is laid for manufacturing the high-quality LED display panel through the complex and effective pretreatment step.

S23, dividing the first image data to obtain independent image data of each bonding pad;

The purpose of this step is to segment the preprocessed image in order to accurately distinguish the specific locations of the individual pads from the whole image.

In particular, the first image data is subjected to graying processing, so that the first image data of color or multiple channels is converted into a gray image, and subsequent processing steps are simplified, because the gray image processing speed is faster, and color information is not necessary for the identification of the bonding pads.

And then, the first image data is segmented by applying an adaptive threshold method, and the method does not need to manually set a threshold, can automatically adjust the threshold according to the illumination conditions of each region of the image, and is suitable for complex or uneven-illumination images.

Finally, morphological operations such as open or closed operations are used to remove small noise and fill small voids in the pad area, which helps to optimize the shape of the pad to be more regular and complete.

Specifically, the adaptive threshold method uses the following formula:

。

Wherein, Is the local threshold value that is calculated and,Is based onIs the average value of the pixels within the window in the center,Is a constant used to fine tune the value of the broadness.

The equation for morphological open operation is as follows:

。

Wherein, Is a binary image after thresholding,Is a structural element of the material, and is a structural element,Indicating the expansion operation.

Similarly, assuming that a specific circuit board image is processed, the image size is 1000x1000 pixels, and the image size comprises a plurality of bonding pads, the bonding pads are unevenly displayed due to different illumination conditions in the manufacturing process, firstly, gray-scale processing is carried out, the complexity of data processing is simplified, then, an adaptive threshold method is applied, the window size is selected to be 15x15 pixels, and the constant is selectedSet to 10 to accommodate the illumination and reflection characteristics of the different pads.

The local threshold value of each pixel is calculated by using the formula, binarization processing is carried out, morphological open operation is then applied, a square of 5x5 pixels is selected by the structural elements, expansion is carried out after erosion, noise points are effectively removed, holes are filled, the final obtained bonding pad image is clear, bonding pad boundaries are obvious, and high-quality input data is provided for subsequent bonding pad quality evaluation.

S24, extracting the characteristics of the independent image data of each bonding pad to obtain the characteristic data of the bonding pad;

Specifically, the feature data includes the geometry, size, boundary definition, and the like of the pad.

In practice, the precise boundary of the pad is determined by using advanced edge detection technology, which is the first step of feature extraction, and is characterized in that the outline of the pad is identified, then geometric parameters of the area, perimeter and shape factor of the pad are calculated, the parameters reflect the size and shape condition of the pad, and then the texture features of the surface of the pad, including surface roughness and the like, are analyzed, which can help to evaluate the manufacturing quality of the pad.

S25, comparing the characteristic data of the bonding pad with standard characteristics to obtain a bonding pad evaluation result.

In the step, a predefined standard feature library including parameters such as the size, the shape factor and the edge definition of a standard bonding pad is required to be imported in advance, the parameters in the extracted feature and the standard feature library are compared by using an image processing algorithm based on the data in the previous step, the deviation between the actual feature and the standard feature is calculated, whether the deviation is within an allowable error range is judged, and whether the bonding pad is qualified is determined according to a deviation evaluation result.

Specifically, during feature comparison, euclidean distance calculation is adopted, and the method specifically comprises the following steps:

。

Wherein, Representing the euclidean distance between the pad feature and the standard feature,Is the actual characteristic value of the bond pad,Is the corresponding standard characteristic value of the standard,Is the number of features.

The deviation evaluation formula is as follows:

。

Wherein, Is a characteristic value of the actual measurement,Is a standard characteristic value.

Assume that a specific pad feature extraction result is: area=200 pixels, perimeter=50 pixels, shape factor=0.8, and the corresponding standard features are: area=195 pixels, perimeter=48 pixels, shape factor=0.82. The above formula was applied for comparison:

1. calculating Euclidean distance:

。

This value reflects the overall difference between the actual feature and the standard feature.

2. Calculating deviation:

Area deviation:

。

Perimeter deviation:

。

Shape factor deviation:

。

based on these calculations, it can be determined whether the pads meet quality criteria. Assuming that the maximum allowable deviation of the quality standard is 5%, the bonding pad meets the quality requirement and can be considered as a qualified product.

S3, silk-screen printing solder paste or conductive adhesive on the circuit board;

after confirming that the pads on the circuit board are complete, step S3 involves silk-screening solder paste or conductive paste on the pads, and the silk-screening technique can accurately apply the solder paste or conductive paste on the designated pads, and these materials will melt in the subsequent soldering process to form stable electrical connection points.

S4, detecting whether each solder paste or conductive adhesive on the circuit board is complete or not through an AOI device, if not, re-executing the step S3 on the circuit board, and if so, executing the next step;

And S4, detecting the integrity of each solder paste or conductive adhesive on the circuit board by using the AOI equipment, wherein the step ensures that the solder paste or conductive adhesive on each bonding pad is uniformly distributed and sufficient in quantity and accurate in position, provides a good foundation for accurately mounting the driving IC and the light-emitting chip, and if the solder paste or conductive adhesive has the problem of uneven distribution or insufficient quantity, the step S3 is required to be returned to re-screen printing, so that the quality of the welding material is ensured to meet the requirements.

S5, welding a driving IC and a light-emitting chip at a bonding pad position corresponding to the circuit board;

After confirming that the solder paste or the conductive paste is complete and correct in step S4, the soldering of the driving IC and the light emitting chip is performed in step S5, which accurately places the driving IC and the light emitting chip on the predetermined bonding pad using a precise placement robot arm, and then the thermal soldering is performed, and the accuracy of this step is critical to ensure the alignment of the IC and the chip with the bonding pad to ensure the reliability and long-term stability of the electrical connection.

S6, detecting whether each driving IC and each light emitting chip on the circuit board are complete or not through an AOI device, if not, re-executing the step S5 on the circuit board, and if so, executing the next step;

Step S6, which uses the AOI device to check whether the driver IC and the light emitting chip are correctly and completely soldered to the circuit board, includes checking the quality of the solder joints and whether the positions of the IC and the chip are accurate, is critical to find possible assembly errors during the production process, and ensures that each component is in the correct position for good electrical connection with the circuit board.

And S7, performing reflow soldering or high-temperature soldering on the circuit board, and powering up to test whether the LED display panel is normal.

Specifically, reflow soldering is to melt solder paste previously screen-printed by heating to form a uniform and firm solder joint. After welding is completed, the functions of the LED display panel are checked through power-on, so that all circuits and pixel points are ensured to work normally, and obvious defects are avoided.

Specifically, step S7 further includes: and if the LED display panel is abnormal in test, repeating the step S6 on the LED panel, and if the test is normal, judging that the LED display panel is a normal LED display panel.

After step S7, the manufacturing process of the LED display panel further includes:

s8, sealing the normal LED display panel in the step S7;

After the LED display panel passes the functional test, a sealing process is performed to protect the circuits and components from the external environment, and the sealing process is required to uniformly cover all the driving ICs and the light emitting chips, provide physical protection, and prevent intrusion of moisture or dust.

S9, detecting whether the sealing glue is normal or not through the AOI equipment, if not, carrying out step S8 on the LED display panel again, and if so, judging the LED display panel as a normal LED display panel;

S10, performing glue curing on the normal LED display panel in the step S9;

And (3) curing the LED display panel subjected to normal sealing, wherein the process involves heating the sealing material in a curing furnace to harden the sealing and firmly fix the sealing on the display panel, and the curing process not only enhances the physical properties of the sealing, but also ensures the long-term environmental protection capability of the sealing.

S11, performing power-on test on the LED display panel subjected to glue curing in the step S10, judging whether the LED display panel subjected to glue curing can normally work, if not, performing scrapping treatment on the LED display panel subjected to glue curing, and if so, obtaining a finished product.

After the colloid is completely solidified, carrying out final power-on test on the LED display panel to check whether all functions of the display panel are normal, including pixel display, color accuracy, response time and the like; if the test fails, the display panel is indicated to have the unrepairable defect and is required to be scrapped; if the test is successful, the LED display panel is qualified in quality, and final packaging and shipment can be performed to obtain a finished product.

The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the description of the present invention and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the invention.

Claims (9)

1. An LED display panel, comprising:

The circuit board (1), the circuit board (1) comprises a display surface (11), a plurality of pixel installation positions (12) are arranged on the display surface (11), the pixel installation positions (12) are distributed at intervals, and each pixel installation position (12) is provided with an anode bonding pad (13), a cathode bonding pad (14), a data input bonding pad (15) and at least three driving output bonding pads (16);

The pixel assembly comprises a plurality of pixel assemblies (2), wherein one pixel assembly (2) is arranged in one pixel installation position (12), each pixel assembly (2) comprises a driving IC (21) and at least three light emitting chips (22), the driving IC (21) is respectively electrically connected with the positive electrode bonding pad (13) and the negative electrode bonding pad (14), the data input bonding pad (15) and the at least three driving output bonding pads (16), the number of the at least three light emitting chips (22) is the same as the number of the at least three driving output bonding pads (16) and corresponds to the at least three driving output bonding pads (16) one by one, and the light emitting chips (22) are respectively electrically connected with the positive electrode bonding pad (13) and the corresponding driving output bonding pads (16).

2. The LED display panel according to claim 1, wherein the positive electrode pad (13) includes a positive electrode vertical extension portion (131), the positive electrode vertical extension portion (131) extends in a first direction, the at least three driving output pads (16) are all disposed on the same side of the positive electrode vertical extension portion (131), and the at least three driving output pads (16) are disposed in parallel and are spaced apart in the first direction.

3. The LED display panel according to claim 2, wherein the data input pads (15) extend in the first direction, the data input pads (15) and the positive vertical extensions (131) are arranged at intervals, and all the drive output pads (16) are arranged between the data input pads (15) and the positive vertical extensions (131).

4. A LED display panel as claimed in claim 3, characterized in that each of the drive output pads (16) extends in a second direction, which is perpendicular to the first direction.

5. A LED display panel as claimed in claim 3, characterized in that the positive electrode pad (13) comprises a first positive electrode lateral extension (132), the first positive electrode lateral extension (132) being connected to the positive electrode vertical extension (131), the negative electrode pad (14) comprising a first negative electrode lateral extension (141), the first positive electrode lateral extension (132) and the first negative electrode lateral extension (141) each extending in a second direction, the second direction being perpendicular to the first direction, a part of the structure of the first positive electrode lateral extension (132) being arranged parallel to and spaced apart from the first negative electrode lateral extension (141), the data input pad (15) and all of the drive output pad (16) being arranged between the first positive electrode lateral extension (132) and the first negative electrode lateral extension (141).

6. The LED display panel of claim 5, wherein a portion of the pixel mounting sites (12) of the plurality of pixel mounting sites (12) are arranged in a column in the second direction;

The positive electrode bonding pad (13) further comprises a second positive electrode transverse extension part (133), the second positive electrode transverse extension part (133) extends in the second direction, the second positive electrode transverse extension part (133) is arranged on one side of the first positive electrode transverse extension part (132) opposite to the first negative electrode transverse extension part (141), and is connected with the first positive electrode transverse extension part (132), and a plurality of second positive electrode transverse extension parts (133) positioned in the same column are connected into a whole;

The negative electrode bonding pad (14) further comprises a second negative electrode transverse extension portion (142), the second negative electrode transverse extension portion (142) extends in the second direction, the second negative electrode transverse extension portion (142) is arranged on one side, opposite to the first positive electrode transverse extension portion (132), of the first negative electrode transverse extension portion (141), and is connected with the first negative electrode transverse extension portion (141), and a plurality of second negative electrode transverse extension portions (142) located in the same column are connected into a whole.

7. The LED display panel according to claim 1, wherein an encapsulation glue (3) is provided on the display surface (11), and the encapsulation glue (3) is light-transmissive and encapsulates all the driving ICs (21) and all the light emitting chips (22).

8. The LED display panel according to claim 1, characterized in that the material of the circuit board (1) is a transparent material.

9. A process for manufacturing the LED display panel according to any one of claims 1 to 8, comprising:

s1, etching an anode bonding pad, a cathode bonding pad, a data input bonding pad and three driving output bonding pads on each pixel installation position of a circuit board;

S2, detecting whether each bonding pad on the circuit board is complete or not through the AOI equipment, if not, re-executing the step S1 on the circuit board, and if yes, executing the next step;

S3, silk-screen printing solder paste or conductive adhesive on the circuit board;

S4, detecting whether each solder paste or conductive adhesive on the circuit board is complete or not through an AOI device, if not, re-executing the step S3 on the circuit board, and if so, executing the next step;

s5, welding a driving IC and a light-emitting chip at a bonding pad position corresponding to the circuit board;

S6, detecting whether each driving IC and each light emitting chip on the circuit board are complete or not through an AOI device, if not, re-executing the step S5 on the circuit board, and if so, executing the next step;

And S7, performing reflow soldering or high-temperature soldering on the circuit board, and powering up to test whether the LED display panel is normal.