LED array expansion detection device and expansion method

Abstract

The present invention relates to the field of LED display manufacturing, and specifically to an LED array detection device, which comprises: a carrier film, on which LED chips arranged in an array are adhered; a stretching device, arranged at the edge of the carrier film, used to stretch the carrier film; metal sheets arranged on the side of adjacent LED chips in the same row or column in the LED array, and two metal sheets arranged on the side corresponding to the adjacent LED chips form a pair; a voltage applicator, used to apply voltage to adjacent metal sheets; a capacitance detection unit, respectively connected to the paired metal sheets, used to detect the capacitance value between adjacent metal sheets; a controller, electrically connected to the capacitance detector, used to calculate the corresponding LED chip spacing according to the capacitance value, and send a signal to the stretching device to stretch or stop stretching when the LED chip spacing reaches a threshold. The device can accurately measure the spacing between LED chips.

Description

Technical Field

[0001] The present invention relates to the technical field of LED display manufacturing, and in particular to an LED array expansion detection device and a detection method. Background Art

[0002] Micro-LED displays have advantages in stability, lifespan and operating temperature. They also inherit the advantages of LED such as low power consumption, color saturation, fast response speed and strong contrast, and have great application prospects. In the production process of existing Micro-LED displays, it is necessary to transfer LED chips from their respective growth substrates to the display backplane of the display; when transferring LED chips to display backplanes of different sizes, since the original arrangement spacing of the LED chips is different from the size spacing of the display backplane to be applied, the original arrangement spacing of the LED chips needs to be adjusted to meet specific usage requirements. Transferring LED chips one by one to the display backplane is also a way to achieve this. With the rapid development of LED technology, the size of LED chips used in LED display screens is getting smaller and smaller, and the spacing between LED core particles in LED chips is also getting smaller and smaller. The difficulty of transferring LED core particles in LED chips has greatly increased. How to provide a simple and fast method for sorting and transferring LED core particles is an urgent problem to be solved in the LED field. Summary of the invention

[0003] Based on the above problems, the present invention designs an LED array detection device, which can accurately and conveniently detect the spacing between LED chips during the crystal expansion process. The specific structure is as follows.

[0004] An LED array detection device, comprising:

[0005] A carrier film, on which the LED chips arranged in an array are adhered, and the carrier film is extensible;

[0006] A stretching device, disposed at an edge of the carrier film, for stretching the carrier film;

[0007] The metal sheets are arranged on the side surfaces of the adjacent LED chips in the same row or column, and the two metal sheets arranged on the corresponding side surfaces of the adjacent LED chips form a pair;

[0008] A voltage applicator, connected to the paired metal sheets respectively, for applying a voltage to the paired metal sheets;

[0009] A capacitance detection unit, connected to the paired metal sheets respectively, for detecting the capacitance value between each pair of the metal sheets;

[0010] The controller is electrically connected to the capacitance detection unit and is used to calculate the corresponding LED chip spacing according to the capacitance value, and send a stretching or stopping stretching signal to the stretching device when the LED chip spacing reaches a threshold value.

[0011] Furthermore, the controller calculates the corresponding LED chip spacing according to the following formula:

[0012]

[0013] Wherein, the vacuum dielectric constant ε0=1; k is the electrostatic force constant; S is the facing area of ​​the paired metal sheets; and L is the distance between the two metal sheets.

[0014] Furthermore, the carrier film is provided with a plurality of through holes, and the through holes are provided at the intersection of the lines connecting the vertices of the four adjacent LED chips.

[0015] Furthermore, the metal sheet is adhered to the side surface of the LED chip by photoresist, heat-sensitive adhesive or photosensitive adhesive.

[0016] Furthermore, the capacitance detection unit is a capacitance detector or a capacitance detection circuit.

[0017] The present invention also includes a method for expanding an LED array, comprising the following steps:

[0018] S10, a plurality of LED chips are adhered to a carrier film in an array, the carrier film is extensible, a metal sheet is arranged on the side of at least two adjacent LED chips in the same row or column in the LED array, the metal sheet is adhered to the LED chip by glue, and two metal sheets arranged on the corresponding sides of the adjacent LED chips form a pair, and each pair of the metal sheets is connected to a voltage applicator and a capacitance detection unit connected to a controller;

[0019] S11: the carrier film is connected to a stretching device, the stretching device controls the carrier film to stretch in a preset direction, and at the same time, a voltage applicator applies a voltage between the paired metal sheets, and a capacitance detection unit detects the capacitance value between the metal sheets;

[0020] S12 The controller calculates the distance between the LED chips according to the capacitance value. When the distance reaches the threshold, the controller sends a command to the stretching device to stop stretching. Specifically, the corresponding LED chip distance is calculated according to the following formula:

[0021]

[0022] Among them, the vacuum dielectric constant ε0=1; k is the electrostatic force constant; S is the facing area of ​​the paired metal sheets; and L is the distance between the two metal sheets, that is, the LED distance.

[0023] Furthermore, after step S12, step S13 is also included to remove the glue. The glue is photoresist, photosensitive glue or thermosensitive glue. The photoresist can be removed by a developer, and the photosensitive glue or thermosensitive glue can be removed by light or heating. After the glue is removed, an LED array with a preset distance is obtained.

[0024] Furthermore, after step S13, step S14 is also included to bond the surface of the LED chip away from the carrier film to a packaging substrate, and remove the carrier film. The method of removing the carrier film is light irradiation or heating.

[0025] The carrier film is provided with a plurality of perforations, which correspond to the LED chips and are located at the intersection of the lines connecting the vertices of four adjacent LED chips.

[0026] Furthermore, in step S11, the carrier film is stretched in one of the lateral and longitudinal directions of the arrangement of the LED chips or in both directions simultaneously.

[0027] The beneficial effects of the present invention are:

[0028] By arranging metal sheets between adjacent LED chips, the metal sheets are adhered to the LED chips by removable glue, and the distance between the metal sheets, that is, the distance between the LED chips, can be calculated by measuring the capacitance between the metal sheets. The structure is simple.

[0029] During the crystal expansion process, the capacitance value between a pair of metal sheets is detected in real time. The change in capacitance has good sensitivity and high precision. When the preset capacitance value is reached, the stretching is stopped immediately, and the distance between the LED chips after crystal expansion can be accurately obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of the cross-sectional structure of Example 1;

[0031] Figure 2 It is a schematic diagram of the top view of the structure of Example 1;

[0032] Figure 3 is a schematic diagram of the cross-sectional structure of Example 2;

[0033] Figure 4 It is a schematic diagram of the top view of the structure of Example 2;

[0034] Figure 5 is a flow chart of the crystal expansion method;

[0035] Figure 6 A schematic diagram of a method for attaching an LED chip to a carrier film;

[0036] Figure 7This is a schematic diagram of the structure in which a metal sheet is arranged on an LED chip;

[0037] Figure 8 It is a structural schematic diagram of the crystal expansion process;

[0038] Fig. 9 This is a schematic diagram of the structure after removing the metal sheet;

[0039] Fig.10 Schematic diagram of the structure of transferring LED chip to packaging substrate.

[0040] Description of the numbers in the figure:

[0041] Carrier film 10 , LED chip 11 , metal sheet 12 , voltage applicator 13 , capacitance detection unit 14 , controller 15 , through-hole 16 , growth substrate 20 . DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. The described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0043] Example 1

[0044] like Figure 1 , Figure 2 As shown, an LED array expansion detection device is demonstrated.

[0045] For details, please refer to Figure 1 The LED array expansion detection device described in this embodiment includes a carrier film 10, and LED chips 11 adhered to the carrier film 10 in an array. The carrier film 10 is extensible, so the distance L of the LED chips 11 can be increased by stretching. At the same time, the carrier film 10 has initial viscosity, and the LED chip 11 can be adhered to the carrier film 10 without moving. The carrier film 10 is one of a blue film, a photolytic tape or a thermal adhesive. The blue film is a blue film for crystal expansion commonly used in the industry, which has excellent extensibility and peelability. Similarly, the photolytic tape and the thermal adhesive tape also have initial viscosity and extensibility. The photolytic tape can be removed by irradiating light of a specific wavelength after the crystal expansion is completed to make it lose its viscosity. The thermal adhesive tape can be removed by heating after the crystal expansion is completed to make it lose its viscosity. In this embodiment, the carrier film 10 is preferably a blue film.

[0046] A metal sheet 12 is arranged on the side of the adjacent LED chips 11 in the same row or column in the LED array. Usually, one metal sheet 12 corresponds to one or more LED chips 11. The specific position setting is set according to needs so that it can be well fixed on the side of the LED chip 11 and conveniently connected to the voltage applicator 13.

[0047] Two metal sheets 12 disposed on the corresponding sides of adjacent chips form a pair. Figure 2 As shown, each pair of metal sheets 12 is respectively connected to two ends of a voltage applicator 13 , so that the voltage applicator can apply a voltage between the metal sheets 12 .

[0048] Each pair of metal sheets 12 is also connected to a connection capacitance detection unit 14, which can detect the capacitance value between the two metal sheets 12 in real time. After obtaining the capacitance value, the distance L between the two metal sheets 12 can be calculated. The specific calculation formula is: Among them, ε0=1, vacuum dielectric constant; k, electrostatic force constant; S, the area facing each other, that is, the area facing each pair of metal sheets 12; L, the distance between each pair of metal sheets 12, that is, the LED distance. 0 , k, and S are all known quantities. Based on the detected capacitance C, the value of the corresponding LED chip spacing L can be calculated.

[0049] The capacitance detection unit 14 is electrically connected to a controller 15, which is equivalent to a central control device and can control the operation of a crystal expansion device (not shown) and the operation of the capacitance detection unit 14. The capacitance detection unit 14 can be a capacitance detection circuit within the controller 15 or a separate capacitance detection device.

[0050] When the wafer expansion device is Figure 1 and Figure 2 When the carrier film 10 is stretched in the direction indicated by the arrow at both ends of the x-axis, the voltage applicator 13 applies a voltage to the pair of metal sheets 12, and the capacitance detection unit 14 detects the capacitance value between the pair of metal sheets 12 in real time. When the spacing L between the LED chips reaches a threshold, the controller 15 sends a stretching signal to the crystal expansion device. The predetermined capacitance value corresponds to a predetermined LED chip spacing value L.

[0051] Optionally, the threshold value can be set according to actual needs, and is not specifically limited here. For example, it can be set according to the degree of crystal expansion required, that is, the width and length of expansion.

[0052] Example 2

[0053] like Figure 3 , Figure 4 As shown, another LED array expansion detection device is demonstrated.

[0054] For details, please refer to Figure 1The LED array expansion detection device described in this embodiment includes a carrier film 10, and LED chips 11 in an array adhered to the carrier film 10. The carrier film 10 is extensible, so the distance L of the LED chips 11 can be increased by stretching. At the same time, the carrier film 10 has initial adhesion, so that the LED chips 11 can be adhered to the carrier film 10 without moving.

[0055] Optionally, the carrier film 10 is a blue film, a photolytic tape or a thermally degradable tape.

[0056] The carrier film 10 is provided with a plurality of perforations 16, which are arranged corresponding to the LED chips 11. Specifically, the perforations 16 are arranged at the intersection of the lines connecting the vertices of the four adjacent LED chips 11, that is, the intersection of the center line P1 of the horizontal spacing of the LED chips 11 and the center line P2 of the vertical spacing. When the carrier film 10 is stretched by an external force, the perforations 16 can block the stress of the carrier film 10 to a certain extent, making the stress of the carrier film 10 more uniform, so that during the stretching process, the deformation of the carrier film 10 is more uniform. The perforations 16 are through holes of micron size, which penetrate the carrier film 10. The size of the perforations 16 should not be too large, as too large a size will affect the arrangement of the LED chips 11.

[0057] Metal sheets 12 are arranged on the side of adjacent LED chips 11 in the same row or column in the LED array. Usually, one metal sheet 12 corresponds to one or more LED chips 11. The metal sheet 12 is adhered to the side of the LED chip 11 by glue, and the glue is one of photoresist, photosensitive glue or thermosensitive glue. The photoresist can be removed by a developer, and the photosensitive glue or thermosensitive glue can be removed by light or heating, which is convenient to remove and has a simple process.

[0058] Two metal sheets 12 disposed on the corresponding sides of adjacent chips form a pair. Figure 3 As shown, each pair of metal sheets 12 is respectively connected to two ends of a voltage applicator 13 , so that the voltage applicator can apply a voltage between the metal sheets 12 .

[0059] Each pair of metal sheets 12 is connected to a capacitance detection unit 14, which can detect the capacitance value between the two metal sheets 12 in real time. After obtaining the capacitance value, the distance L between the two metal sheets 12 can be calculated according to the capacitance calculation formula shown in Example 1.

[0060] The capacitance detection unit 14 is electrically connected to a controller 15, which is equivalent to a central control device and can control the operation of a crystal expansion device (not shown) and the operation of the capacitance detection unit 14. The capacitance detection unit 14 can be a capacitance detection circuit within the controller 15 or a separate capacitance detection device.

[0061] When the wafer expansion device is Figure 3 and Figure 4 When the carrier film 10 is stretched in the direction indicated by the two ends of the x-axis indicated by the middle arrow, the voltage applicator 13 applies a voltage to the pair of metal sheets 12, and the capacitance detection unit 14 detects the capacitance value between the pair of metal sheets 12 in real time, and calculates the spacing L between the LED chips 11 according to the capacitance value. When the spacing L reaches a threshold, the controller 15 sends a stretching signal to the crystal expansion device. A predetermined capacitance value corresponds to a predetermined LED chip spacing value L.

[0062] Example 3

[0063] like Figure 5-10 FIG. 4 is a method for expanding an LED array (i.e., a method for expanding a crystal) according to the present invention. Figure 5 This is a flow chart of the implementation method, and the specific steps are as follows:

[0064] S10 adheres the multiple LED chips 11 on the growth substrate 20 to the carrier film 10 in an array, and a metal sheet 12 is arranged on the side of at least two adjacent LED chips 11 in the same row or column in the LED array, and the metal sheet 12 is adhered to the LED chip 11 by glue.

[0065] like Figure 6 The carrier film 10 shown has extensibility and initial adhesion, so that the LED chip 11 can be adhered to the carrier film 10 without moving.

[0066] like Figure 7 As shown, the metal sheet 12 is adhered to the LED chip 11 by glue, and the two metal sheets 12 arranged on the corresponding sides of the adjacent LED chips 11 form a pair, and each pair of metal sheets 12 is connected to a voltage applicator 13 and a capacitance detection unit 14 connected to a controller 15.

[0067] S11 The carrier film 10 is connected to a stretching device, which controls the carrier film 10 to stretch in a preset direction. At the same time, the voltage applicator 13 applies voltage between the metal sheets 12, and the capacitance detection unit 14 detects the capacitance value between the metal sheets.

[0068] like Figure 8 As shown, in this embodiment, the stretching direction of the carrier film 10 is along the two ends of the transverse x-axis. It should be noted that the stretching direction can also be along the longitudinal y-axis, or the transverse x-axis and the longitudinal y-axis are stretched at the same time, depending on the specific situation. S12 The controller 15 calculates the spacing between the LED chips 11 according to the capacitance value. When the spacing reaches the threshold, the controller 15 sends a command to the stretching device to stop stretching.

[0069] like Figure 8As shown, the carrying film 10 is stretched, and the capacitance detection unit 14 detects the capacitance value and sends it to the controller 15. The distance L between the LED chips 11 is calculated according to the capacitance value between the metal sheets 12. When the distance L reaches the threshold, the controller 15 sends a command to the stretching device to stop stretching.

[0070] Each pair of metal sheets 12 is connected to a capacitance detection unit 14, which can detect the capacitance value between the two metal sheets 12 in real time. After obtaining the capacitance value, the distance L between the two metal sheets 12 can be calculated. The specific calculation formula is: Among them, ε0=1, vacuum dielectric constant; k, electrostatic force constant; S, the area of ​​the two plates facing each other; L, the distance between the two plates, i.e., the distance between the LEDs. Since ε0, k, and S are all known quantities, the value of the distance L between the corresponding LED chips can be calculated based on the detected capacitance C.

[0071] S13 removes the glue by using a developer.

[0072] like Fig. 9 As shown, the metal sheet 12 is adhered to the side of the LED chip 11 through the photoresist, and the photoresist can be removed by simply placing the photoresist in a developer.

[0073] In other embodiments, the metal sheet 12 may be adhered to the side of the LED chip 11 with photosensitive adhesive. The photosensitive adhesive may lose its viscosity through laser irradiation, thereby removing the metal sheet 12 without causing stress to the LED chip 11 .

[0074] S14: transferring the LED chip 11 after the crystal expansion to the packaging substrate 30, and then removing the carrier film 10.

[0075] like Fig.10 As shown, the carrier film 10 is one of a blue film, a photolytic tape or a thermal adhesive. The blue film is a blue film commonly used in the industry for crystal expansion, which has excellent extensibility and peelability. Similarly, the photolytic tape and the thermal adhesive tape also have initial adhesion and extensibility. The photolytic tape can be removed by irradiating light of a specific wavelength to make it lose its viscosity after the crystal expansion is completed, and the thermal adhesive tape can be removed by heating to make it lose its viscosity after the crystal expansion is completed. In this embodiment, the carrier film 10 is preferably a blue film.

[0076] It should be noted that this embodiment only describes the simplest crystal expansion process (i.e., Micro-LED array expansion). In other embodiments, crystal expansion is only implemented in part of the LED array. When the spacing of the LED chips 11 in a certain area meets the requirements, the LED chips 11 in this area are transferred before the next crystal expansion. Therefore, the metal sheet 12 is only attached to the side of one or more LED chips 11, not necessarily the side of the entire row or column of chips as shown in the figure.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0078] The basic principles of the present disclosure are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present disclosure. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, and are not limitations. The above details do not limit the present disclosure to the necessity of adopting the above specific details to be implemented.

Claims

1. An LED array detection device, characterized in that: include: A carrier film, on which the LED chips arranged in an array are adhered, and the carrier film is extensible; A stretching device, disposed at an edge of the carrier film, for stretching the carrier film; The metal sheets are arranged on the side surfaces of the adjacent LED chips in the same row or column, and the two metal sheets arranged on the corresponding side surfaces of the adjacent LED chips form a pair; A voltage applicator, connected to the paired metal sheets respectively, for applying a voltage to the paired metal sheets; A capacitance detection unit, connected to the paired metal sheets respectively, for detecting the capacitance value between each pair of the metal sheets; A controller, electrically connected to the capacitance detection unit, for calculating the corresponding LED chip spacing according to the capacitance value, and sending a stretching or stopping stretching signal to the stretching device when the LED chip spacing reaches a threshold value; The controller specifically calculates the corresponding LED chip spacing according to the following formula: Wherein, C is the capacitance value; the vacuum dielectric constant ε0=1; k is the electrostatic force constant; S is the facing area of ​​the paired metal sheets; and L is the distance between the paired metal sheets.

2. The LED array detection device according to claim 1, characterized in that: The carrier film is provided with a plurality of perforations, which correspond to the LED chips and are located at the intersection of the lines connecting the vertices of four adjacent LED chips.

3. The LED array detection device according to claim 1, characterized in that: The metal sheet is adhered to the side surface of the LED chip by photoresist, heat-sensitive adhesive or photosensitive adhesive.

4. The LED array detection device according to claim 1, characterized in that: The capacitance detection unit is a capacitance detector or a capacitance detection circuit.

5. A method for expanding an LED array, characterized in that: The steps include: S10, a plurality of LED chips are adhered to a carrier film in an array, the carrier film is extensible, a metal sheet is arranged on the side of at least two adjacent LED chips in the same row or column in the LED array, the metal sheet is adhered to the LED chip by glue, and two metal sheets arranged on the corresponding sides of the adjacent LED chips form a pair, and each pair of the metal sheets is connected to a voltage applicator and a capacitance detection unit connected to a controller; S11: the carrier film is connected to a stretching device, the stretching device controls the carrier film to stretch in a preset direction, and at the same time, a voltage applicator applies a voltage between the paired metal sheets, and a capacitance detection unit detects the capacitance value between the metal sheets; S12 The controller calculates the distance between the LED chips according to the capacitance value. When the distance reaches the threshold, the controller sends a command to the stretching device to stop stretching. Specifically, the corresponding LED chip distance is calculated according to the following formula: Wherein, C is the capacitance value; the vacuum dielectric constant ε0=1; k is the electrostatic force constant; S is the facing area of ​​the paired metal sheets; and L is the distance between the paired metal sheets.

6. The LED array expansion method according to claim 5, characterized in that: After step S12, step S13 is also included to remove the glue. The glue is photoresist, photosensitive glue or thermosensitive glue. The photoresist can be removed by a developer, and the photosensitive glue or thermosensitive glue can be removed by light or heating. After the glue is removed, an LED array with a preset distance is obtained.

7. The LED array expansion method according to claim 6, characterized in that: After step S13, the method further includes step S14 of bonding the surface of the LED chip away from the carrier film to a packaging substrate, and removing the carrier film. The method of removing the carrier film is light irradiation or heating.

8. The LED array expansion method according to claim 5, characterized in that: The carrier film is provided with a plurality of through holes, and the through holes are provided at the intersection of the lines connecting the vertices of four adjacent LED chips.

9. The LED array expansion method according to claim 5, characterized in that: In step S11, the carrier film is stretched in one of the transverse and longitudinal directions of the arrangement of the LED chips or in both directions simultaneously.

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