Wafer LED chip wide BIN sorting method, display module manufacturing method and display module

Abstract

This invention discloses a novel wide-bin sorting method for circular LED chips, comprising: setting two or three consecutive wavelength screening intervals for a single color of the LED chip; performing characteristic tests on the circular LED chips to obtain test data, the test data including the dominant wavelength of each LED chip; screening qualified LED chips based on the test data, and mapping the LED chips to the corresponding wavelength screening intervals based solely on the dominant wavelength of the LED chips to obtain bin transfer data; and transferring the LED chips on the circular chip to a transfer board corresponding to the wavelength screening interval based on the bin transfer data. Compared with the prior art, this invention sets a wider range of bin intervals, resulting in fewer bins (only two or three), thus improving bin utilization. This invention also discloses a display module manufacturing method and a display module. This method encapsulates and divides LED chips on the same transfer board into LED beads, mixes them, and installs them on a circuit board to form a display module, which can effectively improve the color consistency of the display.

Description

Technical Field

[0001] This invention relates to an LED chip sorting technology, and more particularly to a wide-bin sorting method for circular LED chips and a method for manufacturing display modules. Background Technology

[0002] In the production of LED displays, considering the significant differences in the electrical and optical characteristics of the LED chips used in the display modules, optical differences can arise within a single display module or between different display modules. This reduces the visual experience for the human eye and, due to the concentration of electrical or optical characteristics of the LED chips, increases the difficulty of LED display calibration due to modular light color issues. Therefore, to solve the problem of optical differences within a single display module or between different display modules, the display end implements electrical or optical range control over the source of LED chips. The control conditions are mainly based on the dominant wavelength and brightness of the LED chip's light emission (e.g., WLD: 2.5nm; LOP: 15%). For the LED chip manufacturing process, selecting LED chips that meet the dominant wavelength and brightness conditions and grouping them together is called binning (or binning). Sorting according to narrow bin conditions (e.g., WLD: 2.5nm; LOP: 15%) can result in multiple bins (at least 5 bins) within a single LED wafer. The specific BIN sorting process is as follows: the wafer spot test generates Excel data, the traditional sorting equipment generates a mapping diagram and sorts the BINs onto the wafers according to product requirements; and according to the display requirements, the wafers of specific BINs are selected for die bonding to the target board, and the wafers of other unused BINs are put into the warehouse for processing.

[0003] However, with the increasing demand for LED chips, traditional bin sorting methods can lead to several problems. On the one hand, it can result in a large inventory of LED chips (unused bins will be temporarily stored, and the inventory will increase over time). On the other hand, traditional bin sorting methods can result in low wafer utilization and low sorting efficiency (traditional sorting equipment uses a pick and place method for sorting, and due to the large number of bins, the blue film needs to be replaced frequently during transfer), which greatly increases the cost of LED chips.

[0004] Therefore, a method for sorting LED chips that solves the above problems is needed. Summary of the Invention

[0005] The purpose of this invention is to provide a wide bin sorting method for circular LED chips and a display module manufacturing method. This sorting method effectively reduces the cost of LED chip sorting, solves the problem of large inventory of unsuitable bins after sorting, and the display module has good color consistency and can use LED chips sorted by bin.

[0006] To achieve the above objectives, this invention discloses a novel wide-bin sorting method for circular LED chips, comprising: setting two or three consecutive wavelength screening intervals for a color of the LED chip; performing characteristic tests on the circular LED chips to obtain test data, the test data including the dominant wavelength of each LED chip; screening out qualified LED chips based on the test data, and mapping the LED chips to the corresponding wavelength screening intervals based solely on the dominant wavelength of the LED chips to obtain BIN transfer data, the transfer data including the correspondence between the LED chips and the wavelength screening intervals; and transferring the LED chips on the circular chip to a transfer board corresponding to the wavelength screening interval based on the BIN transfer data.

[0007] Preferably, transferring the LED chips on the wafer to the transfer board corresponding to the wavelength selection interval based on the BIN transfer data specifically includes: importing the BIN transfer data into a needle-punch sorting device, the needle-punch sorting device also acquiring a scan image of the LED chips on the wafer, generating a drawing map based on the BIN transfer data and the scan image of the LED chips, indicating the position of the LED chips and the wavelength selection interval corresponding to the LED chips, and the needle-punch sorting device transferring the LED chips on the wafer to the transfer board corresponding to the wavelength selection interval based on the markings on the drawing map.

[0008] Preferably, when the LED chip is a blue LED chip, the blue LED chip is provided with a first wavelength selection range and a second wavelength selection range, the first wavelength selection range being 461-466nm and the second wavelength selection range being 466-472nm; when the LED chip is a green LED chip, the green LED chip is provided with a third wavelength selection range and a fourth wavelength selection range, the third wavelength selection range being 526-532nm and the second wavelength selection range being 532-538nm.

[0009] Preferably, the length of the wavelength screening interval is greater than or equal to 4 nanometers and less than or equal to 6 nanometers.

[0010] Preferably, the test data also includes one or more combinations of the LED chip's brightness, reverse current, transient peak voltage, low-current startup voltage, and operating voltage. Each test data has a corresponding qualified range, and the qualified range of the dominant wavelength is the set of wavelength screening ranges for the LED chip of the current color. Screening qualified LED chips based on the test data includes: identifying LED chips whose test data all conform to the corresponding qualified range as qualified LED chips, and identifying LED chips whose test data does not conform to the corresponding qualified range as unqualified LED chips.

[0011] Specifically, when the LED chip is a blue LED chip, the acceptable range for brightness is 5-20 mcd, the acceptable range for reverse current is less than or equal to 0.01uA, the acceptable range for transient peak voltage is less than or equal to 0.01V, the acceptable range for low-current startup voltage is greater than or equal to 2.12V and less than or equal to 2.3V, and the acceptable range for operating voltage is greater than or equal to 2.75V and less than or equal to 3.05V; when the LED chip is a green LED chip, the acceptable range for brightness is 61-107 mcd, the acceptable range for reverse current is less than or equal to 0.01uA, the acceptable range for transient peak voltage is less than or equal to 0.01V, the acceptable range for low-current startup voltage is greater than or equal to 1.85V and less than or equal to 2.03V, and the acceptable range for operating voltage is greater than or equal to 2.55V and less than or equal to 2.75V.

[0012] Compared with existing technologies, this invention divides the qualified range of the main wavelength of an LED chip of a single color into two or three consecutive wavelength screening ranges, resulting in a wider BIN range after sorting. This wide BIN sorting solves the problems of low wafer utilization efficiency and low sorting efficiency caused by excessive BIN sorting of traditional wafers, and also solves the problem of large inventory of other unused BINs of LED chips, indirectly reducing the cost of LED chip sorting. Moreover, when LED chips on a disc are transferred through the needle-punch sorting device, the frequency of blue film replacement is reduced, and the transfer efficiency is improved.

[0013] The present invention also discloses a method for manufacturing a display module, comprising: obtaining LED chips sorted by the wide BIN sorting method of the circular LED chips as described above; mounting the LED chips on a transfer board onto a first substrate and encapsulating and cutting them to form LED beads; mixing the LED beads formed by encapsulating the LED chips on the same transfer board and mounting them on a circuit board.

[0014] Preferably, transferring an LED chip from a transfer plate to a first substrate and then encapsulating and cutting it to form an LED bead specifically includes: mounting an LED chip from a transfer plate onto a first substrate; encapsulating the LED chip mounted on the first substrate to obtain a first package; and cutting the first package between adjacent LED chips to obtain an LED bead.

[0015] Specifically, the LED chips sorted by the wide BIN sorting method for circular LED chips include first-color LED chips and second-color LED chips; "mixing LED beads packaged from LED chips on the same transfer board and mounting them on a circuit board" specifically means: mixing LED beads packaged from first-color LED chips on the same transfer board and LED beads packaged from second-color LED chips on the same transfer board respectively and then mounting them on the same circuit board, forming a plurality of display units on the circuit board, each display unit including at least one first-color LED chip and at least one second-color LED chip.

[0016] More specifically, a third color LED chip is also obtained when acquiring the first color LED chip and the second color LED chip; the third color LED chip is transferred onto a first substrate; LED beads packaged from the first color LED chip on the same transfer board and LED beads packaged from the second color LED chip on the same transfer board are mixed and then mounted on the same circuit board in a position matching with the LED beads packaged from the third color LED chip, and a plurality of display units are formed on the circuit board, each display unit including at least one first color LED chip, at least one second color LED chip and at least one third color LED chip.

[0017] Preferably, the LED chips sorted by the wide BIN sorting method for circular LED chips include first-color LED chips and second-color LED chips; the first-color LED chips on one transfer plate and the second-color LED chips on another transfer plate are respectively transferred to the same first substrate to form a plurality of display units, each display unit including at least one first-color LED chip and at least one second-color LED chip; the display units on the first substrate are packaged to obtain a first package; the first package is cut between adjacent display units to obtain LED beads; the LED beads packaged from the first-color LED chips and the second-color LED chips on the same transfer plate are mixed and mounted on a circuit board.

[0018] Specifically, a third color LED chip is also acquired when acquiring the first color LED chip and the second color LED chip; the first color LED chip, the second color LED chip and the third color LED chip on the transfer board are respectively transferred to the same first substrate to form a plurality of display units, each of the display units including at least one first color LED chip, at least one second color LED chip and at least one third color LED chip.

[0019] Specifically, the first color LED chip is a blue LED chip, the second color LED chip is a green LED chip, and the third color LED chip is a red LED chip.

[0020] The present invention also discloses a display module, which is manufactured by the display module manufacturing method described above.

[0021] Compared with existing technologies, this invention features wide bin sorting. During the manufacturing of the display module, the LED chips in a bin are first packaged into LED beads. Then, the LED beads manufactured in a bin are mixed and installed on the circuit board to form the display module. This solves the problem of color blockage in the module caused by the concentration of LED bead brightness, and improves the color consistency of the LED product display effect. It also solves the optical differences within or between individual display modules, i.e., the "color block" problem. Therefore, the bin sorting conditions can be relaxed for the LED chip end, thus realizing the wide bin sorting process for LED chips. Attached Figure Description

[0022] Figure 1 This is a flowchart of the wide BIN sorting method for circular LED chips according to the present invention.

[0023] Figure 2 This is a flowchart of the method for manufacturing the display module of the present invention.

[0024] Figure 3 This is a diagram illustrating the process of combining a drawn image with a scanned image using the needle-punching sorting device of the present invention.

[0025] Figure 4 This is a process diagram of the display module manufacturing method in the first embodiment of the present invention.

[0026] Figure 5 This is a process diagram of the display module manufacturing method in the second embodiment of the present invention.

[0027] Figure 6 This is a process diagram of the display module manufacturing method in the third embodiment of the present invention. Detailed Implementation

[0028] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0029] refer to Figure 1 This invention discloses a wide-bin sorting method for circular LED chips. Before sorting, two or three consecutive wavelength filtering intervals are set for one color of the LED chip, and a transfer plate corresponding to the wavelength filtering intervals is set. Steps S11 to S13 are executed during sorting.

[0030] In this embodiment, two consecutive wavelength selection ranges are set for a single color of the LED chip. When the LED chip is a blue LED chip, a first wavelength selection range and a second wavelength selection range are set accordingly. The first wavelength selection range is 461-466nm, and the second wavelength selection range is 466-472nm. When the LED chip is a green LED chip, a third wavelength selection range and a fourth wavelength selection range are set accordingly. The third wavelength selection range is 526-532nm, and the second wavelength selection range is 532-538nm. In this embodiment, the first wavelength selection range may or may not include 461nm; 466nm may or may not be included in the first or second wavelength selection range. The second wavelength selection range may or may not include 472nm. The third wavelength selection range may or may not include 526nm; 532nm may or may not be included in the third or fourth wavelength selection range. The fourth wavelength selection range may or may not include 538nm.

[0031] In this embodiment, the length of the wavelength screening interval is greater than or equal to 4 nanometers and less than or equal to 6 nanometers.

[0032] The transfer board includes a first transfer board corresponding to the first wavelength selection range, a second transfer board corresponding to the second wavelength selection range, a third transfer board corresponding to the third wavelength selection range, and a fourth transfer board corresponding to the fourth wavelength selection range. The first transfer board corresponding to the first wavelength selection range is referred to as BIN1 of the blue LED, and the second transfer board corresponding to the second wavelength selection range is referred to as BIN2 of the blue LED. The third transfer board corresponding to the third wavelength selection range is referred to as BIN1 of the red LED, and the fourth transfer board corresponding to the fourth wavelength selection range is referred to as BIN2 of the red LED.

[0033] Step S11: Perform characteristic tests on the LED chips of the wafer to obtain test data, including the dominant wavelength of each LED chip.

[0034] The test data also includes one or more combinations of LED chip brightness, reverse current, transient peak voltage, low current start-up voltage, and operating voltage. Each test data has a corresponding qualified range, and the qualified range of the main wavelength is the set of wavelength screening ranges of the LED chip of the current color.

[0035] Specifically, when the LED chip is a blue LED chip, the acceptable range for brightness is 5-20 mcd, the acceptable range for reverse current is less than or equal to 0.01uA, the acceptable range for transient peak voltage is less than or equal to 0.01V, the acceptable range for startup voltage under low current is greater than or equal to 2.12V and less than or equal to 2.3V, and the acceptable range for operating voltage is greater than or equal to 2.75V and less than or equal to 3.05V.

[0036] Specifically, when the LED chip is a green LED chip, the acceptable range for brightness is 61-107 mcd, the acceptable range for reverse current is less than or equal to 0.01uA, the acceptable range for transient peak voltage is less than or equal to 0.01V, the acceptable range for startup voltage under low current is greater than or equal to 1.85V and less than or equal to 2.03V, and the acceptable range for operating voltage is greater than or equal to 2.55V and less than or equal to 2.75V.

[0037] For LED chips of the same color, test data other than the dominant wavelength are not used as the basis for BIN (Binding Indicator), but only as the basis for qualification screening.

[0038] Step S12: Select qualified LED chips based on the test data, and match the LED chips to the corresponding wavelength screening range based only on the main wavelength of the LED chips to obtain BIN conversion data. The conversion data includes the correspondence between the LED chips and the wavelength screening range.

[0039] The process of selecting qualified LED chips based on the test data includes: identifying qualified LED chips whose test data for each LED chip meets the corresponding qualified range, and identifying unqualified LED chips whose test data for any LED chip does not meet the corresponding qualified range.

[0040] Step S13: Transfer the LED chip on the wafer to the transfer board corresponding to the wavelength selection range according to the BIN transfer data.

[0041] Specifically, a needle-punch sorting device is used to transfer the LED chips on the wafer to a transfer plate corresponding to the wavelength selection range. See reference [link to relevant documentation]. Figure 3First, the BIN-separated data is imported into the needle punch sorting device. Then, the needle punch sorting device uses software algorithms to generate a mapping diagram (see [link to relevant documentation]). Figure 3 (b) of the diagram shows a drawing of a disc and a drawing of an LED chip, with the LED chip's wavelength selection range (or transfer plate, BIN) marked on the drawing of the LED chip. Figure 3 The LED chip located in the first wavelength screening range (the first transfer plate at the transfer target position) is denoted as LED1. Figure 3 The LED chip located in the first wavelength screening range (second transfer plate of the transfer target position) is denoted as LED2 and marked with different lines or images. The disc of the LED chip corresponding to the generated drawing is placed on the blue film platform of the needle-punch sorting device. The needle-punch sorting device scans the disc to obtain the scanned image of the disc (see...). Figure 3 In (a) of the diagram, the scanned image of the wafer contains the outline of the wafer and images of the LED chips. A coordinate system for the scanned image is established using specific marker points on the wafer as reference points. The mechanical coordinate information of each LED chip is obtained from the scanned image. The drawn image and the scanned image are aligned using the specific marker points on the wafer to achieve a composite image (e.g., ...). Figure 3 As shown in the diagram, a map is generated that marks the positions of LED chips and the corresponding wavelength selection intervals. Finally, the needle-punch sorting device transfers the LED chips at the corresponding positions on the disc to a transfer plate corresponding to their wavelength selection intervals, based on the markings on the map. The markings on the map refer to the position information of the LED chips on the map and the transfer plate corresponding to the wavelength selection interval of the LED chip at that position, i.e., the position and transfer purpose of the LED chips.

[0042] The purpose of using a needle-punch sorting device is that the needle-punch method can transfer chips smaller than 0204 and larger, while traditional pick-and-place devices can only handle chips larger than 0305 due to the diameter of the nozzle. Moreover, under the condition of fewer bins (two or three bins), the needle-punch sorting device first transfers all the chips in bin 1 and then transfers the chips in bin 2, reducing the frequency of blue film replacement. The transfer tool of the needle-punch sorting device is a pin, which has a greater range of motion than the swing arm combined with the nozzle transfer method of traditional sorting devices.

[0043] In this embodiment, the transfer plate is generally a glass substrate with a temporary bonding adhesive layer. The LED chip is transferred to the transfer plate by needle punching and bonded to the temporary bonding adhesive layer.

[0044] refer to Figure 2 The present invention also discloses a method for manufacturing a display module, including steps S21 to S25.

[0045] S21 obtains the LED chips 12 sorted by the wide BIN sorting method described above, and the LED chips 12 are carried on the corresponding transfer board 10 (e.g., Figure 4 (as shown in (a)).

[0046] S22 mounts the LED chip 12 on the transfer plate 10 onto the first substrate 11 (e.g., ...). Figure 4 (as shown in (b)).

[0047] S23 encapsulates the LED chip 12 mounted on the first substrate 11 with an encapsulation layer 13 to obtain a first package (such as...). Figure 4 (as shown in (c)).

[0048] S24 cuts the first package between adjacent LED chips 12 to obtain LED beads 30 (e.g., ... Figure 4 (as shown in (d) and (e)).

[0049] S25 mixes the LED beads 30 made from the LED chips 12 on the same transfer board 10 and mounts them on a circuit board 21 (e.g., ...). Figure 4 As shown in (f) in the figure, a display module 20 is made in this way.

[0050] In this embodiment, the first substrate can be a BT substrate, or a glass substrate, ceramic substrate, etc., with circuitry. In step S22, the transfer plate 10 carrying the LED chip 12 is aligned and bonded to the target first substrate 11, and the LED chip 12 is fixed to the first substrate 11 by laser welding. Then, the transfer plate 10 is removed, and the LED chip 12 on the transfer plate 10 is transferred to the first substrate 11, and the LED chip 12 and the first substrate 11 are bonded together. The LED chip 12 has electrodes, and the first substrate 11 has pads. The electrodes of the LED chip 12 are aligned and welded to the pads on the first substrate 11, and the LED chip 12 is mounted on the first substrate 11.

[0051] In this embodiment, mixing the LED beads 30 made from the LED chips 12 on the same transfer plate 10 specifically involves uniformly inserting the front half of the LED beads 30 on the first substrate 10 into the rear half of the LED beads 30 on the first substrate 10. Alternatively, the LED beads 30 made on the first substrate 10 can be randomly shuffled to complete the mixing.

[0052] The process involves chip packaging via molding, followed by dicing to create individual chip packages ("LED beads"). These packages are then mixed using a dot-matrix system (the purpose of dot-matrix mixing is to resolve optical differences within or between individual display modules, i.e., the "color block" problem; dot-matrix mixing randomly disperses the LED beads, thus solving the color block problem caused by concentrated brightness and improving the color consistency of the LED product display). Furthermore, because the dot-matrix system's mixing function resolves the optical differences within or between individual display modules, the binning conditions for the 12-pin LED chip can be relaxed, enabling wide binning of the 12-pin LED chip. After electrical control, the LED beads are transferred to a blue film, and finally, a traditional pick-and-place device is used to die-bond the LED beads onto the module (i.e., circuit board 21). The LED bead size is generally 0404 or larger for easy transfer and installation.

[0053] refer to Figure 5 In one embodiment, the LED chips sorted by the circular LED chip wide BIN sorting method include blue LED chips 12a and green LED chips 12b. The display module manufacturing method includes:

[0054] S21a, reference Figure 5 In (a), obtain the blue LED chip 12a on the first transfer board 10a, obtain the green LED chip 12b on the third transfer board 10b, and obtain the red LED chip 12c in the preset main wavelength range.

[0055] S22a, reference Figure 5 In (b) of the diagram, blue LED chip 12a, green LED chip 12b, and red LED chip 12c are respectively mounted on a first substrate 11 to form a plurality of RGB units 120. Each RGB unit 120 includes at least one blue LED chip 12a, at least one green LED chip 12b, and at least one red LED chip 12c. In this embodiment, each RGB unit 120 includes one blue LED chip 12a, one green LED chip 12b, and one red LED chip 12c. In the illustration, the blue LED chip 12a, green LED chip 12b, and red LED chip 12c are arranged in parallel to form the RGB unit 120. Of course, the blue LED chip 12a, green LED chip 12b, and red LED chip 12c can also be arranged adjacently in a triangular or other manner to form the RGB unit 120.

[0056] S23a, reference Figure 5In (c), an encapsulation layer 13 is encapsulated on the RGB unit 120 on the first substrate 11 to obtain a first package.

[0057] S24a, reference Figure 5 In (d) and (e), the first package is cut from between adjacent RGB units 120 to obtain LED beads 30a.

[0058] S25a, reference Figure 5 In (f), LED beads 30a, which are packaged from blue LED chip 12a on the same first transfer board 10a, green LED chip 12b on the same second transfer board 10b and red LED chip 12c, are mixed and installed on a circuit board 21 to form a display module 20 (product 1).

[0059] In this embodiment, after obtaining the LED bead 30a packaged from the RGB unit 120, the LED bead 30a can be mixed with other LEDs, and then the LED bead 30a can be mounted on the circuit board 20.

[0060] Preferably, in step S22a, after mixing the corresponding LED chips on the transfer board, the LED chips of each color are grouped and mounted on the first substrate 11 to form a plurality of RGB units 120.

[0061] In this embodiment, the blue LED chips 12a and the green LED chips 12b in the LED beads 30a mounted on the circuit board 20 belong to the same BIN. Here, "same BIN" does not refer to LED chips transferred from a single wafer in a mechanical sense, but rather to a type of BIN (transfer board) corresponding to a dominant wavelength range. The LED beads 30a made from the blue LED chips 12a in the same BIN are mixed and then mounted on the circuit board 20, and the green LED beads 30a made from the green LED chips 12b in the same BIN are mixed and then mounted on the same circuit board.

[0062] In this embodiment, the first wavelength selection interval corresponds to the third wavelength selection interval, the second wavelength selection interval is paired with the fourth wavelength selection interval, and the wavelength selection interval of the blue LED chip 12a obtained in S21a is paired with the wavelength selection interval of the green LED chip 12b. In this embodiment, the first transfer board and the third transfer board are used as examples. Of course, they can also be the blue LED chip 12a on the second transfer board and the green LED chip 12b on the fourth transfer board, under which product 2 will be obtained in step S25a. However, this is not limited to this; in another embodiment, the first wavelength selection interval can be paired with the fourth wavelength selection interval, and the second wavelength selection interval can be paired with the third wavelength selection interval. During maintenance, a replacement LED chip needs to be taken from the BIN (transfer board) corresponding to the original wavelength selection interval. Therefore, the display module of this invention can obtain products with two wavelength band combinations. In the subsequent module product calibration process, this reduces the complexity of chip wavelength combinations in the product, indirectly reducing the complexity of calibration and improving the standardization of the product.

[0063] refer to Figure 6 In another embodiment, the LED chips sorted by the circular LED chip wide BIN sorting method include blue LED chips 12a and green LED chips 12b. The display module manufacturing method includes:

[0064] S21b, reference Figure 6 In (a), obtain the blue LED chip 12a on the first transfer board 10a, obtain the green LED chip 12b on the third transfer board 10b, and obtain the red LED chip in the preset main wavelength range.

[0065] S22b, reference Figure 6 In (b), a blue LED chip 12a is mounted on a first substrate 11, a green LED chip 12b is mounted on a first substrate 11, and a red LED chip 12c is mounted on a first substrate 11.

[0066] S23b, reference Figure 6 In (c), an encapsulation layer 13 is formed on the blue LED chip 12a, green LED chip 12b and red LED chip 12c on the first substrate 11 to obtain the first package corresponding to the respective colors.

[0067] S24b, Reference Figure 6 In (d) and (e), the first package is cut between the blue LED chips 12a to obtain a blue LED bead 31, between the green LED chips 12b to obtain a green LED bead 32, and between the red LED chips 12c to obtain a red LED bead 33.

[0068] S25b, reference Figure 6 In (f), blue LED beads 31 are mixed with green LED beads 32 and red LED beads 33, and then mounted on a circuit board 20 to form a plurality of RGB units 120a. Each RGB unit 120a includes at least one blue LED bead 31, at least one green LED bead 32 and at least one red LED bead 33. In this embodiment, each RGB unit 120a includes one blue LED bead 31, one green LED bead 32 and one red LED bead 33, thereby forming a display module 20a (product 1).

[0069] In this embodiment, blue LED beads made from blue LED chips 12a in the same BIN are mixed and installed on a circuit board, and green LED beads made from green LED chips 12b in the same BIN are mixed and installed on a circuit board.

[0070] In this embodiment, the first wavelength selection interval is paired with the third wavelength selection interval, the second wavelength selection interval is paired with the fourth wavelength selection interval, and the wavelength selection interval of the blue LED chip 12a obtained in S21b is paired with the wavelength selection interval of the green LED chip 12b. In this embodiment, the first transfer board 10a and the third transfer board 10b are used as examples. Of course, they can also be the blue LED chip 12a on the second transfer board and the green LED chip 12b on the fourth transfer board, respectively. Under this condition, product 2 will be obtained in step S25b. However, this is not limited to this; the first wavelength selection interval can also be paired with the fourth wavelength selection interval, and the second wavelength selection interval can be paired with the third wavelength selection interval. During maintenance, a replacement LED chip needs to be taken from the BIN (transfer board) corresponding to the original wavelength selection interval. Therefore, the display module of this invention can obtain products with two wavelength band combinations. In the subsequent module product calibration process, this reduces the complexity of chip wavelength combinations in the product, indirectly reducing the complexity of calibration and improving the standardization of the product.

[0071] The chip package (i.e., "LED bead") can be a single-chip package, meaning the package contains only one chip; or it can be a multi-chip package, meaning the package includes chips of three LED colors (RGB). For example, all three LED colors are transferred to the same target board, and at least one color chip is transferred to the first substrate 11 after being sorted using the above sorting method. Generally, the main wavelength of the incoming red LED chips meets the condition of being within the range of 6nm, so no binning is required. However, the green LED chip 12b and the blue LED chip 12a must be sorted using the above sorting method. When the red LED chip uses a vertical structure, a wire bonding process is required before lamination packaging to connect the electrode on the side of the red LED chip facing away from the pad to the corresponding pad on the circuit board.

[0072] The display module generated by this invention can be a multi-color display module or a monochrome display module.

[0073] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A display module manufacturing method, characterized by comprising: The application relates to a wafer LED chip wide BIN sorting method. Two or three continuous wavelength screening intervals are set for a color of LED chips; Characteristics of the LED chips on a wafer are tested to obtain test data, wherein the test data comprises a main wavelength of each LED chip; According to the test data, qualified LED chips are screened out, and the LED chips are corresponded to corresponding wavelength screening intervals only according to the main wavelengths of the LED chips to obtain BIN sorting data, wherein the sorting data comprises a corresponding relationship between the LED chips and the wavelength screening intervals; According to the BIN sorting data, the LED chips on the wafer are transferred to transfer plates corresponding to the wavelength screening intervals to obtain LED chips sorted by the wafer LED chip wide BIN sorting method, wherein the LED chips comprise first color LED chips and second color LED chips; The LED chips on the transfer plates are mounted on a first substrate and subjected to packaging cutting to form LED lamp beads; The LED lamp beads packaged by the first color LED chips on the same transfer plate and the LED lamp beads packaged by the second color LED chips on the same transfer plate are respectively subjected to mixed light packaging and are mounted on the same circuit board, and a plurality of display units are formed on the circuit board, wherein each display unit comprises at least one first color LED chip and at least one second color LED chip.

2. The display module manufacturing method of claim 1, wherein: According to the BIN sorting data, the LED chips on the wafer are transferred to transfer plates corresponding to the wavelength screening intervals, specifically, the BIN sorting data is imported into a needle sorting device, the needle sorting device also acquires a scanning diagram of the LED chips on the wafer, a drawing map marked with positions of the LED chips and wavelength screening intervals corresponding to the LED chips is generated according to the BIN sorting data and the scanning diagram of the LED chips, and the needle sorting device transfers the LED chips on the wafer to the transfer plates corresponding to the wavelength screening intervals according to the marks on the drawing map.

3. The method of claim 1, wherein: When the LED chips are blue light LED chips, the blue light LED chips are correspondingly provided with a first wavelength screening interval and a second wavelength screening interval, the first wavelength screening interval is 461-466 nm, and the second wavelength screening interval is 466-472 nm. When the LED chips are green LED chips, the green LED chips are correspondingly provided with a third wavelength screening interval and a fourth wavelength screening interval, the third wavelength screening interval is 526-532 nm, and the second wavelength screening interval is 532-538 nm.

4. The method of claim 1, wherein: The length of the wavelength screening interval is greater than or equal to 4 nm and less than or equal to 6 nm.

5. The method of claim 1, wherein: The test data further comprises one or more combinations of brightness, reverse current, transient peak voltage, starting voltage under low current, working voltage of the LED chips, each test data has a corresponding qualified interval, and the qualified interval of the main wavelength is a combination of wavelength screening intervals of the LED chips of the current color. The LED chips qualified according to the test data include: identifying the LED chip whose each test data is consistent with the corresponding qualified interval as a qualified LED chip, and identifying the LED chip whose any test data is not consistent with the corresponding qualified interval as an unqualified LED chip.

6. The method for manufacturing a display module as described in claim 5, characterized in that: When the LED chip is a blue LED chip, the qualified interval of the luminance is 5-20 mcd, the qualified interval of the reverse current is less than or equal to 0.01 uA, the qualified interval of the transient peak voltage is less than or equal to 0.01 V, the qualified interval of the starting voltage under low current is greater than or equal to 2.12 V and less than or equal to 2.3 V, and the qualified interval of the working voltage is greater than or equal to 2.75 V and less than or equal to 3.05 V. When the LED chip is a green LED chip, the qualified interval of the luminance is 61-107 mcd, the qualified interval of the reverse current is less than or equal to 0.01 uA, the qualified interval of the transient peak voltage is less than or equal to 0.01 V, the qualified interval of the starting voltage under low current is greater than or equal to 1.85 V and less than or equal to 2.03 V, and the qualified interval of the working voltage is greater than or equal to 2.55 V and less than or equal to 2.75 V.

7. The method of claim 1, wherein the display module is made by the steps of: providing a display module; providing a display module cover; and attaching the display module cover to the display module. The transferring of the LED chip on the transfer plate to the first substrate and the package cutting to form the LED lamp bead specifically include: The transferring of the LED chip on the transfer plate to the first substrate; The package of the LED chip mounted on the first substrate to obtain a first package body; The cutting of the first package body between adjacent LED chips to obtain LED lamp beads.

8. The method of claim 1, wherein: The third color LED chip is obtained when the first color LED chip and the second color LED chip are obtained; the LED lamp beads packaged by the first color LED chips on the same transfer plate and the LED lamp beads packaged by the second color LED chips on the same transfer plate are respectively mixed and then mounted on the same circuit board in position cooperation with the LED lamp beads packaged by the third color LED chips, and a plurality of display units are formed on the circuit board, each display unit including at least one first color LED chip, at least one second color LED chip and at least one third color LED chip.

9. The method of claim 1, wherein: The wafer LED chip wide BIN sorting method sorts the LED chips including first color LED chips and second color LED chips; The first color LED chip on one transfer plate and the second color LED chip on one transfer plate are respectively transferred to the same first substrate, and a plurality of display units are formed, each display unit including at least one first color LED chip and at least one second color LED chip; The display units on the first substrate are packaged to obtain a first package body; The first package body is cut between adjacent display units to obtain LED lamp beads; The wafer LED chip wide BIN sorting method sorts the LED chips including first color LED chips and second color LED chips; The first color LED chip on one transfer plate and the second color LED chip on one transfer plate are respectively transferred to the same first substrate, and a plurality of display units are formed, each display unit including at least one first color LED chip and at least one second color LED chip; The display units on the first substrate are packaged to obtain a first package body; The first package body is cut between adjacent display units to obtain LED lamp beads; The LED lamp beads packaged by the first color LED chip on the same transfer plate and the second color LED chip on the same transfer plate are mixed and installed on a circuit board.

10. The method of claim 9, wherein the display module is made by the steps of: A third color LED chip is obtained when the first color LED chip and the second color LED chip are obtained; the first color LED chip on the transfer plate, the second color LED chip on the transfer plate and the third color LED chip are transferred to the same first substrate respectively, and a plurality of display units are formed, each of the display units comprising at least one first color LED chip, at least one second color LED chip and at least one third color LED chip. ​ 11. The method of claim 10, wherein: The first color LED chip is a blue LED chip, the second color LED chip is a green LED chip, and the third color LED chip is a red LED chip.

12. A display module, characterized by: The display module is made by the manufacturing method of any one of claims 1 to 11.

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