Display device manufacturing method
The method addresses the challenge of replacing defective LED elements in LED display devices by using a stamp to form new connection pads and mount new elements precisely, enhancing manufacturing efficiency and maintaining image quality.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- JAPAN DISPLAY INC
- Filing Date
- 2025-11-07
- Publication Date
- 2026-07-23
AI Technical Summary
In the manufacturing of LED display devices, removing defective LED elements and forming new connection pads only at the removed locations is challenging due to the difficulty in precise placement without affecting adjacent good LED elements.
A method involving the use of a stamp with a convex portion to position a connecting material for new connection pads and mount new LED elements without interfering with existing good elements, allowing for precise placement during the replacement process.
Enables efficient removal and replacement of defective LED elements with new ones while maintaining the integrity of the surrounding good elements, simplifying the manufacturing process and ensuring high-resolution image display.
Smart Images
Figure JP2025039166_23072026_PF_FP_ABST
Abstract
Description
Method for manufacturing a display device
[0001] The present invention relates to a method for manufacturing a display device, and more particularly, to a technique effective when applied to a method for manufacturing a display device having light-emitting diode elements, for example.
[0002] Japanese Patent Application Laid-Open No. 2021-144970 (Patent Document 1) describes a technique related to a repair part in which defective micro LED chips can be easily replaced.
[0003] Japanese Patent Application Laid-Open No. 2022-105856 (Patent Document 2) describes a technique related to a method for manufacturing a micro LED display that can improve productivity.
[0004] Japanese Patent Application Laid-Open No. 2021-144970 Japanese Patent Application Laid-Open No. 2022-105856
[0005] There is an LED (Light Emitting Diode) display device that uses a plurality of light-emitting diode elements arranged on a substrate called a backplane as a light source in the display device. In the LED display device, the LED elements are mounted on the electrodes formed on the backplane via connection pads. When the LED elements thus mounted are defective, after removing the defective LED elements, new LED elements may be mounted again.
[0006] In this regard, when removing defective LED elements, the connection pads on which the LED elements are mounted may also be removed together. In this case, it is necessary to form new connection pads. However, it is difficult to form new connection pads only at the removed locations among the connection pads on which good LED elements are mounted. Therefore, in a method for manufacturing a display device including a step of remounting new LED elements after removing defective LED elements, a device for forming new connection pads only at the removed locations is desired.
[0007] Other problems and novel features will become apparent from the description of this specification and the accompanying drawings.
[0008] One embodiment of the method for manufacturing a display device includes the steps of: (a) preparing an LED-equipped backplane having a backplane on which a first electrode and a second electrode are formed, a first connection pad formed on the first electrode, a second connection pad formed on the second electrode, a first light-emitting diode element mounted on the first connection pad, and a second light-emitting diode element mounted on the second connection pad; (b) inspecting the LED-equipped backplane by lighting up a plurality of light-emitting diode elements mounted on the LED-equipped backplane; (c) removing any defective light-emitting diode elements that do not light up in step (b) above; and (d) forming a new connection pad on the electrode that was exposed after the removal of the connection pad if, in step (c) above, the connection pad on which the defective light-emitting diode element was mounted has also been removed.
[0009] Here, step (d) includes (d1) preparing a stamp having a convex portion that is convex downwards, (d2) forming a connecting material that will become a new connecting pad at the lower end of the convex portion, and (d3) lowering the stamp with a good light-emitting diode element mounted on it, thereby positioning the connecting material formed at the lower end of the convex portion onto the electrode without interfering with the good light-emitting diode element.
[0010] One embodiment of the method for manufacturing a display device includes the steps of: (a) preparing an LED-equipped backplane having a backplane on which a first electrode and a second electrode are formed, a first connection pad formed on the first electrode, a second connection pad formed on the second electrode, a first light-emitting diode element mounted on the first connection pad, and a second light-emitting diode element mounted on the second connection pad; (b) inspecting the LED-equipped backplane by lighting up a plurality of light-emitting diode elements mounted on it; (c) removing any defective light-emitting diode elements that do not light up in step (b) above; and (d) mounting a new light-emitting diode element on an electrode exposed by removing the connection pad via a new connection pad if, in step (c) above, the connection pad on which the defective light-emitting diode element was mounted has also been removed.
[0011] Here, step (d) includes (d1) preparing a stamp having a convex portion that is convex downwards, (d2) holding a new light-emitting diode element having a connecting material that will become a new connecting pad formed on its lower surface with the convex portion, and (d3) with a good light-emitting diode element mounted, lowering the stamp to position the new light-emitting diode element, which is held by the convex portion and has a connecting material that will become a new connecting pad formed on its lower surface, onto the electrode without interfering with the good light-emitting diode element.
[0012] This is a plan view showing an example configuration of a display device. This is a circuit diagram showing an example configuration of the circuit around the pixel shown in Figure 1. This is a diagram showing an example of the pixel configuration. This is a cross-sectional view showing an example of the pixel configuration. This is a flowchart explaining the flow of the manufacturing process of a display device. This is a diagram showing the manufacturing process of a display device in an embodiment. This is a diagram showing the manufacturing process of a display device following Figure 6. This is a diagram showing the manufacturing process of a display device following Figure 7. This is a diagram showing the manufacturing process of a display device following Figure 8. This is a diagram showing the manufacturing process of a display device following Figure 9. This is a diagram showing the manufacturing process of a display device following Figure 10. This is a diagram showing the process of forming a new connection pad in an embodiment. This is a diagram showing the process of forming a new connection pad in an embodiment. This is a diagram showing the process of mounting a new LED element in an embodiment. This is a diagram showing the process of mounting a new LED element in an embodiment. This is a diagram showing a process in which the process of forming a new connection pad and the process of mounting a new LED element are carried out simultaneously in a modified example. This is a diagram showing a process in which the process of forming a new connection pad and the process of mounting a new LED element are carried out simultaneously in a modified example.
[0013] The embodiments will be described below with reference to the drawings.
[0014] This disclosure is merely an example, and any modifications that maintain the spirit of this disclosure while being appropriately conceivable by a person skilled in the art are naturally included within the scope of this disclosure.
[0015] Furthermore, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc., of each part compared to the actual embodiment, but these are merely examples and do not limit the interpretation of this disclosure. In this specification and each drawing, elements similar to those shown in previously published drawings are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.
[0016] In this embodiment, as an example of a display device using multiple light-emitting diode elements, a micro-LED display device equipped with multiple micro-LED elements is provided. Micro-LED elements have a smaller size (outer diameter) compared to general LED elements. Therefore, micro-LED display devices can display high-resolution images.
[0017] <Configuration of the display device> Figure 1 is a plan view showing an example of the configuration of a display device.
[0018] In Figure 1, the boundary between the display area DA and the peripheral area PFA, the control circuit 5, the drive circuit 6, and the multiple pixels PIX are each shown by dashed lines.
[0019] Figure 2 is a circuit diagram showing an example of the configuration of the circuit around a pixel shown in Figure 1. Note that the pixel circuit shown in Figure 2 is an example of an equivalent circuit corresponding to one pixel PIX shown in Figure 1.
[0020] Figure 1 shows the X and Y directions. The X and Y directions intersect each other. In the example described below, the X direction is perpendicular to the Y direction. Furthermore, the X-Y plane, which includes the X and Y directions, will be described as a plane parallel to the display surface of the display device.
[0021] Unless otherwise explicitly stated, "planar view" refers to a view of a plane parallel to the X-Y plane. Furthermore, the direction normal to the X-Y plane is described as the "Z direction" or thickness direction. The X, Y, and Z directions are intersecting directions. For example, the X, Y, and Z directions are orthogonal directions.
[0022] As shown in Figure 1, the display device DSP1 has a display area DA, a peripheral area PFA, and a plurality of pixels PIX. The peripheral area PFA surrounds the display area DA in a frame-like manner. The plurality of pixels PIX are arranged in a matrix within the display area DA.
[0023] The display device DSP1 also includes a substrate 10, a control circuit 5, and a drive circuit 6. The control circuit 5 and the drive circuit 6 are each formed on the substrate 10.
[0024] The control circuit 5 is a circuit for controlling the display in the display device DSP 1. For example, the control circuit 5 is a driver IC (Integrated Circuit) mounted on the substrate 10. In Figure 1, the control circuit 5 is arranged, for example, along one of the four short sides that make up the outer shape of the substrate 10. The control circuit 5 includes a signal line drive circuit. The signal line drive circuit is a video driver. The signal line drive circuit is a circuit that supplies video signals to video signal lines. The location and configuration examples of the control circuit 5 are not limited to the example shown in Figure 1. For example, in Figure 1, a circuit board such as a flexible substrate may be connected to the location shown as the control circuit 5. In this case, the control circuit 5 is mounted on the circuit board. Also, for example, the signal line drive circuit may be formed separately from the control circuit 5.
[0025] The drive circuit 6 is a scanning driver. The drive circuit 6 is a circuit that supplies scanning signals to the scanning signal line. The drive circuit 6 supplies scanning signals to the scanning signal line based on a control signal from the control circuit 5. The drive circuit 6 is arranged, for example, along each of the two long sides of the four sides that make up the outer shape of the substrate 10. In the example shown in Figure 1, in a plan view, the display area DA is located between the two drive circuits 6. The position and configuration examples of the drive circuit 6 are not limited to the example shown in Figure 1. For example, in Figure 1, a circuit board such as a flexible substrate may be connected to the position shown as the drive circuit 6. In this case, the drive circuit 6 is mounted on the circuit board.
[0026] Next, using Figure 2, we will explain an example of the configuration of a pixel circuit that drives a pixel PIX.
[0027] In Figure 2, a representative pixel circuit is shown to drive one pixel. Each of the multiple pixels PIX shown in Figure 1 is equipped with a circuit similar to the pixel circuit shown in Figure 2. The pixel circuit is a voltage signal type circuit that controls the light emission state of the LED element 20 based on the video signal Vsg supplied from the control circuit 5 (see Figure 1).
[0028] As shown in Figure 2, each pixel PIX is equipped with an LED element 20. The LED element 20 is a light-emitting diode element. The LED element 20 has an anode electrode 20EA and a cathode electrode 20EC.
[0029] The display device DSP1 is equipped with multiple types of wiring in the display area DA. These wirings include multiple scan signal lines GLS, GLR, GLB, multiple video signal lines VL, multiple power lines PL1, multiple power lines PL2, and multiple reset wiring RSL.
[0030] The scan signal lines GLS, GLR, and GLB extend in the X direction. The scan signal lines GLS, GLR, and GLB are connected to the drive circuit 6. For example, as shown in Figure 1, the scan signal lines GLS, GLR, and GLB for driving even-numbered pixels PIX among the pixels PIX arranged in the Y direction are connected to one drive circuit 6. In contrast, the scan signal lines GLS, GLR, and GLB for driving odd-numbered pixels PIX are connected to the other drive circuit 6. As another example, a configuration in which all of the scan signal lines GLS and GLR are connected to one drive circuit 6, and all of the scan signal lines GLB are connected to the other drive circuit 6 is also conceivable. Thus, there are cases in which one of the scan signal lines GLS, GLR, and GLB is connected to one drive circuit 6, and the rest are connected to the other drive circuit 6.
[0031] The video signal line VL, power lines PL1 and PL2, and reset wiring RSL extend in the Y direction. The video signal line VL is connected to the control circuit 5 (see Figure 1). The video signal Vsg and initialization signal are supplied to the video signal line VL from the control circuit 5. High potential Pdvdd is supplied to power line PL1 from the control circuit 5. Low potential Pvss, which is lower than high potential Pdvdd, is supplied to power line PL2 from the control circuit 5. The reset signal Vrs is supplied to the reset wiring RSL from the control circuit 5.
[0032] The control circuit 5 outputs a start pulse signal and a clock signal (not shown) to the drive circuit 6. The drive circuit 6 includes multiple shift register circuits. Based on the clock signal, the drive circuit 6 sequentially transfers the start pulse signal to the next stage shift register circuit. In this way, the drive circuit 6 sequentially supplies scan signals to each scan signal line GLS, GLR, and GLB.
[0033] The pixel circuit controls the LED element 20 based on the video signal Vsg supplied to the video signal line VL. To achieve this control, the pixel circuit includes a reset transistor RST, a pixel selection transistor SST, an output transistor BCT, a drive transistor DRT, a holding capacitor Cs, and an auxiliary capacitor Cad. The auxiliary capacitor Cad is an element provided to adjust the amount of light emitted.
[0034] The reset transistor RST, pixel selection transistor SST, output transistor BCT, and drive transistor DRT are switching elements made of thin-film transistors (TFTs). The conductivity type of the thin-film transistors is not particularly limited. For example, all transistors may be made of N-channel TFTs. However, at least one of the transistors may be made of P-channel TFTs.
[0035] The reset transistor RST, pixel selection transistor SST, output transistor BCT, and drive transistor DRT are formed, for example, using the same process and the same layer structure. These transistors have a bottom gate structure with polycrystalline silicon used for the semiconductor layer. As another example, the reset transistor RST, pixel selection transistor SST, output transistor BCT, and drive transistor DRT may have a top gate structure. For example, oxide semiconductors or polycrystalline GaN semiconductors can be used as the semiconductor layer.
[0036] The reset transistor RST, the pixel selection transistor SST, the output transistor BCT, and the drive transistor DRT each have a source electrode, a drain electrode, and a gate electrode. The gate electrode of each transistor is a control electrode. The source electrode and drain electrode of each transistor can also be simply referred to as electrodes.
[0037] The drive transistor DRT and the output transistor BCT are connected in series with the LED element 20 between power lines PL1 and PL2. The high potential Pvdd supplied to power line PL1 is set to, for example, 10V. The low potential Pvss supplied to power line PL2 is set to, for example, 1.5V.
[0038] The drain electrode of the output transistor BCT is connected to the power line PL1. The source electrode of the output transistor BCT is connected to the drain electrode of the drive transistor DRT. The gate electrode of the output transistor BCT is connected to the scan signal line GLB. The output transistor BCT is turned on / off by the control signal Gsb supplied to the scan signal line GLB. Here, "on" represents a conduction state, and "off" represents a non-conduction state. The output transistor BCT controls the light emission time of the LED element 20 based on the control signal Gsb.
[0039] The source electrode of the drive transistor DRT is connected to one electrode of the LED element 20 (here, the anode electrode 20EA). The other electrode of the LED element 20 (here, the cathode electrode 20EC) is connected to the power line PL2. The drive transistor DRT outputs a drive current to the LED element 20 based on the video signal Vsg.
[0040] The source electrode of the pixel selection transistor SST is connected to the video signal line VL. The drain electrode of the pixel selection transistor SST is connected to the gate electrode of the drive transistor DRT. The gate electrode of the pixel selection transistor SST is connected to the scan signal line GLS. The scan signal line GLS functions as a gate trace for signal writing control. The pixel selection transistor SST is turned on / off by the control signal Gss supplied from the scan signal line GLS. Turning the pixel selection transistor SST on / off switches the connection and disconnection between the pixel circuit and the video signal line VL. That is, by turning on the pixel selection transistor SST, the video signal Vsg or initialization signal from the video signal line VL is supplied to the gate electrode of the drive transistor DRT.
[0041] The source electrode of the reset transistor RST is connected to the reset wiring RSL. The drain electrode of the reset transistor RST is connected to the source electrode of the drive transistor DRT and the anode electrode 20EA of the LED element 20. The gate electrode of the reset transistor RST is connected to the scan signal line GLR. The scan signal line GLR functions as a gate wiring for reset control. The reset transistor RST is turned on / off by the control signal Grs supplied from the scan signal line GLR. By switching the reset transistor RST on, the potentials of the source electrode of the drive transistor DRT and the anode electrode 20EA of the LED element 20 can be reset. That is, the potentials of the source electrode of the drive transistor DRT and the anode electrode 20EA of the LED element 20 can be reset to the reset signal Vrs supplied to the reset wiring RSL. In other words, the reset wiring RSL is wiring for resetting the voltage of the LED element 20.
[0042] The retaining capacitance Cs is connected between the gate electrode and source electrode of the drive transistor DRT. The auxiliary capacitance Cad is connected between the source electrode of the drive transistor DRT and the power line PL2.
[0043] The drive circuit 6 sequentially supplies scanning signals (control signals Gss, Grs, Gsb) to each of the scanning signal lines GL S, GL R, GL B. That is, the control signals Gss, Grs, Gsb are sequentially supplied to the scanning signal lines GL S, GL R, GL B of each line (a series of pixels PIX arranged in the X direction) based on the start pulse signal and the clock signal. Further, the control circuit 5 sequentially supplies the video signal Vsg and the initialization signal to each video signal line VL. The charge held in the holding capacitor Cs is initialized with the supply of the initialization signal as the video signal Vsg is supplied.
[0044] In the configuration as described above, the pixel circuit is driven by the control signals Gss, Grs, Gsb supplied to the scanning signal lines GL S, GL R, GL B. On the other hand, the LED element 20 emits light with a luminance corresponding to the video signal Vsg supplied to the video signal line VL.
[0045] <Configuration of Pixel> Next, the configuration of the pixel PIX will be described.
[0046] FIG. 3 is a diagram showing a configuration example of the pixel PIX.
[0047] The pixel PIX has a plurality of LED elements. Specifically, the pixel PIX has one red LED element 20R, one green LED element 20G, one blue LED element 20B, and one electrode 20C. The electrode 20C is an electrode corresponding to the power supply line PL2 to which the low potential Pvss is supplied, as shown in FIG. 2.
[0048] FIG. 4 is a cross-sectional view showing a configuration example of the pixel PIX.
[0049] In FIG. 4, the pixel PIX has a backplane BP, an electrode 101A, an electrode 101B, an electrode 101C, connection pads 102A, connection pads 102B, connection pads 102C, a red LED element 20R, a green LED element 20G, a blue LED element 20B, an insulating film 103, contact holes 104A, contact holes 104B, contact holes 104C, and a transparent conductive film 105.
[0050] Electrodes 101A, 101B, and 101C are formed on the backplane BP. A connecting pad 102A is formed on electrode 101A. A connecting pad 102B is formed on electrode 101B. A connecting pad 102C is formed on electrode 101C. Connecting pads 102A, 102B, and 102C are made of a metal film. The metal film is made of, for example, tin (Sn), indium (In), or solder.
[0051] A red LED element 20R is mounted on the connection pad 102A. The red LED element 20R has an anode electrode 30RA and a cathode electrode 30RC. The anode electrode 30RA is electrically connected to the connection pad 102A.
[0052] A green LED element 20G is mounted on the connection pad 102B. The green LED element 20G has an anode electrode 30GA and a cathode electrode 30GC. The anode electrode 30GA is electrically connected to the connection pad 102B.
[0053] A blue LED element 20B is mounted on the connection pad 102C. The blue LED element 20B has an anode electrode 30BA and a cathode electrode 30BC. The anode electrode 30BA is electrically connected to the connection pad 102C.
[0054] An insulating film 103 is formed above the backplane BP so as to cover the red LED element 20R, the green LED element 20G, and the blue LED element 20B. Contact holes 104A, 104B, and 104C are formed in the insulating film 103. Contact hole 104A is formed to reach the cathode electrode 30RC of the red LED element 20R. Contact hole 104B is formed to reach the cathode electrode 30GC of the green LED element 20G. Contact hole 104C is formed to reach the cathode electrode 30BC of the blue LED element 20B.
[0055] A translucent conductive film 105 is formed inside contact hole 104A, contact hole 104B, contact hole 104C, and on the insulating film 103. The translucent conductive film 105 is, for example, an ITO (Indium Tin Oxide) film.
[0056] At the bottom of contact hole 104A, the cathode electrode 30RC is electrically connected to the translucent conductive film 105. At the bottom of contact hole 104B, the cathode electrode 30GC is electrically connected to the translucent conductive film 105. At the bottom of contact hole 104C, the cathode electrode 30BC is electrically connected to the translucent conductive film 105. As a result, the translucent conductive film 105 is electrically connected to the cathode electrode 30RC of the red LED element 20R, the cathode electrode 30GC of the green LED element 20G, and the cathode electrode 30BC of the blue LED element 20B.
[0057] As described above, pixels (PIX) are constructed in this manner.
[0058] <Method for Manufacturing a Display Device> Next, the method for manufacturing a display device according to the embodiment will be described.
[0059] Figure 5 is a flowchart illustrating the manufacturing process of a display device.
[0060] First, prepare the backplane with LED elements (S101). The backplane with LED elements referred to here is a backplane on which LED elements are mounted, and specifically, it is a structure having the configuration shown in Figure 6.
[0061] Figure 6 shows the configuration of a backplane LBP with LED elements.
[0062] In Figure 6, the LED-equipped backplane LBP includes a backplane BP, electrodes 101A, 101B, 101C, connection pads 102A, 102B, 102C, a red LED element 20R, a green LED element 20G, and a blue LED element 20B. The red LED element 20R has an anode electrode 30RA and a cathode electrode 30RC. The green LED element 20G has an anode electrode 30GA and a cathode electrode 30GC. The blue LED element 20B has an anode electrode 30BA and a cathode electrode 30BC.
[0063] This LED-equipped backplane (LBP) can be manufactured as follows.
[0064] For example, a backplane BP having electrodes 101A, 101B, and 101C is prepared. Then, a connecting material such as solder is applied to each of electrodes 101A, 101B, and 101C, and then, for example, a stamp is used to mount a red LED element 20R on electrode 101A, a green LED element 20G on electrode 101B, and a blue LED element 20B on electrode 101C.
[0065] This makes it possible to manufacture an LED-equipped backplane LBP in which a red LED element 20R is mounted on electrode 101A via a connecting pad 102A, a green LED element 20G is mounted on electrode 101B via a connecting pad 102B, and a blue LED element 20B is mounted on electrode 101C via a connecting pad 102C.
[0066] The LED-equipped backplane LBP may be manufactured and prepared by the process described above, or it may be prepared by purchasing an already manufactured LED-equipped backplane LBP.
[0067] Next, the LED-equipped backplane LBP is inspected (S102). Specifically, by using a jig on the LED-equipped backplane LBP, it is checked whether each of the red LED element 20R, green LED element 20G, and blue LED element 20B lights up normally. In other words, it is checked whether there are any defective LED elements (defective light-emitting diode elements) among the red LED element 20R, green LED element 20G, and blue LED element 20B that do not light up. Here, for example, suppose that as a result of the inspection, as shown in Figure 7, the red LED element 20R and blue LED element 20B are normal LED elements, while the green LED element 20G is a defective LED element. In Figure 7, "NG" is written to indicate that the green LED element 20G is a defective LED element.
[0068] In this case, since a defective LED element is present (S103), the defective LED element is removed by irradiating the defective green LED element 20G with laser light (S104). At this time, it is difficult to remove only the defective LED element, and for example, as shown in Figure 8, the connection pad 102B that was connected to the anode electrode 30GA of the defective green LED element 20G is also removed. That is, here, it is assumed that not only the defective green LED element 20G but also the connection pad 102B is removed by the laser light (S105). In this case, the following steps are performed.
[0069] As shown in Figure 9, a new connection pad 110 is formed by applying a connecting material to the electrode 101B that is exposed after the connection pad 102B is removed (S106). Then, as shown in Figure 10, a new LED element 120 is mounted on the new connection pad 110 (S107). The new LED element 120 has an anode electrode 130A and a cathode electrode 130C.
[0070] Next, as shown in Figure 11, an insulating film 103 is formed on the backplane BP so as to cover the red LED element 20R, the new LED element 120, and the blue LED element 20B (S108). Subsequently, contact holes 104A, 104B, and 104C are formed in the insulating film 103 using photolithography and etching techniques (S109). Contact hole 104A is formed to reach the cathode electrode 30RC of the red LED element 20R. Contact hole 104B is formed to reach the cathode electrode 130C of the new LED element 120. Contact hole 104C is formed to reach the cathode electrode 30BC of the blue LED element 20B.
[0071] Next, a translucent conductive film 105 is formed inside the contact hole 104A, inside the contact hole 104B, inside the contact hole 104C and on the insulating film 103 (S110). The translucent conductive film 105 is, for example, an ITO (Indium Tin Oxide) film.
[0072] As a result, at the bottom of contact hole 104A, the cathode electrode 30RC of the red LED element 20R is electrically connected to the translucent conductive film 105. At the bottom of contact hole 104B, the cathode electrode 130C of the new LED element 120 is electrically connected to the translucent conductive film 105. At the bottom of contact hole 104C, the cathode electrode 30BC of the blue LED element 20B is electrically connected to the translucent conductive film 105.
[0073] In this embodiment, the explanation was based on the assumption that defective LED elements are present as a result of the inspection process (S102) of the LED-equipped backplane LBP. However, if no defective LED elements are found as a result of the inspection, the process proceeds from step S103 to step S108. Also, in this embodiment, the explanation was based on the assumption that the lower connection pads are removed when the defective LED elements are removed with laser light. However, if the connection pads are not removed, the process proceeds from step S105 to step S107.
[0074] As described above, the display device according to the embodiment can be manufactured.
[0075] <Features of the Embodiment> For example, in the step of forming a new connection pad 110 on the electrode 101B that is exposed after the connection pad 102B is removed (see Figure 9), while there are connection pads 102A equipped with a good LED element, the red LED element 20R, and connection pad 102C equipped with a good LED element, the blue LED element 20B, it is necessary to form the new connection pad 110 only in the area where the old one was removed. In other words, it is necessary to form the new connection pad 110 only in the area where the old one was removed without interfering with the red LED element 20R and the blue LED element 20B.
[0076] Therefore, in the manufacturing method of the display device in the embodiment that includes a step of removing a defective LED element and then re-mounting a new LED element, a method is employed to form a new connection pad 110 only in the area where the defective element was removed.
[0077] The following describes the features of this embodiment, which represents a key innovation.
[0078] As shown in Figure 12, prepare the stamp STP1. The stamp STP1 has a base material 201 and a convex portion 202 that is convex downwards.
[0079] For example, the amount of protrusion L of the convex portion 202 is greater than the thickness of the light-emitting diode elements (red LED element 20R, blue LED element 20B) in the vertical direction (Y direction).
[0080] Then, a connecting material 110A, which will become a new connecting pad, is formed at the lower end of the protrusion 202. After that, as shown in Figure 13, with good LED elements (red LED element 20R and blue LED element 20B) mounted, the stamp STP1 is lowered along the Y direction. This allows the connecting material 110A formed at the lower end of the protrusion 202 to be placed on the electrode 101B without interfering with the good LED elements. In this way, according to this embodiment, a new connecting pad 110 can be formed only in the removed area without interfering with the red LED element 20R and the blue LED element 20B.
[0081] Next, as shown in Figure 14, the stamp STP2 is prepared. The stamp STP2 has a base material 301 and a convex portion 302 that is convex downwards. The convex portion 302 has the function of holding the new LED element 120, and the new LED element 120 is held by the convex portion 302. For example, an adhesive material is formed on at least the lower end of the convex portion 302, and as a result, the new LED element 120 is held by the convex portion 302.
[0082] Subsequently, as shown in Figure 15, with the good LED elements (red LED element 20R and blue LED element 20B) mounted, the stamp STP2 is lowered along the Y direction. This allows the new LED element 120, held by the protrusion 302, to be placed on the new connection pad 110 without interfering with the good LED elements.
[0083] As described above, according to the method for manufacturing the display device in the embodiment, a defective LED element can be removed without interfering with a good LED element that has already been placed, and then a new LED element can be mounted.
[0084] <Modified Example> The modified example describes an example in which the process of forming the new connection pad 110 and the process of mounting the new LED element 120 are carried out simultaneously. According to the modified example, since the process of forming the new connection pad 110 and the process of mounting the new LED element 120 are carried out simultaneously, the manufacturing process of the display device can be simplified.
[0085] As shown in Figure 16, prepare the stamp STP2. The stamp STP2 has a base material 301 and a convex portion 302 that is convex downwards. The convex portion 302 has the function of holding the new LED element 120. For example, an adhesive material is formed on at least the lower end of the convex portion 302, and the new LED element 120, which has a connecting material 110A that will become a new connecting pad formed on its lower surface, is held by the convex portion 302.
[0086] Subsequently, as shown in Figure 17, with the good LED elements (red LED element 20R and blue LED element 20B) mounted, the stamp STP2 is lowered along the Y direction. This allows the new LED element 120, which is held by the protrusion 302 and has a connecting material 110A that will become a new connecting pad formed on its lower surface, to be placed on the electrode 101B without interfering with the good LED elements. As a result, as shown in Figure 17, the new LED element 120 can be mounted on the electrode 101B via the new connecting pad 110.
[0087] Based on the above, according to the modified version, the process of forming the new connection pad 110 and the process of mounting the new LED element 120 can be carried out simultaneously, thus simplifying the manufacturing process of the display device.
[0088] The present invention has been described in detail above based on its embodiments, but it goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways without departing from its essence.
[0089] Within the scope of the concept of the present invention, a person skilled in the art can conceive of various modifications and alterations, and it is understood that such modifications and alterations also fall within the scope of the present invention. For example, any addition, deletion, or design change of components, or addition, omission, or modification of processes, made by a person skilled in the art to the above-described embodiments, is also included within the scope of the present invention, as long as it retains the gist of the present invention.
[0090] Furthermore, any other effects and advantages brought about by the embodiments described herein that are clear from the description herein or that can be appropriately conceived by a person skilled in the art are naturally considered to be brought about by the present invention.
[0091] 5 Control circuit 6 Drive circuit 10 Substrate 20 LED element 20B Blue LED element 20C Electrode 20EA Anode electrode 20EC Cathode electrode 20G Green LED element 20R Red LED element 30BA Anode electrode 30BC Cathode electrode 30GA Anode electrode 30GC Cathode electrode 30RA Anode electrode 30RC Cathode electrode 101A Electrode 101B Electrode 101C Electrode 102A Connection pad 102B Connection pad 102C Connection pad 103 Insulating film 104A Contact hole 104B Contact hole 104C Contact hole 105 Translucent conductive film 110 New connection pad 110A Connection material 120 New LED element 130A Anode electrode 130C Cathode electrode 201 Substrate 202 Protrusion 301 Substrate 302 Protrusion BCT Output transistor BP Backplane Cad Auxiliary capacitance Cs Holding capacitance DA Display area DRT Drive transistor DSP1 Display device GLB Scan signal line GLR Scan signal line GLS Scan signal line Grs Control signal Gsb Control signal Gss Control signal LBP Backplane with LED element PFA Peripheral area PIX Pixel PIXA Pixel PIXB Pixel PIXC Pixel PL1 Power line PL2 Power line Pvdd High potential Pvss Low potential RSL Reset wiring RST Reset transistor SST Pixel selection transistor STP1 Stamp STP2 Stamp
Claims
1. A method for manufacturing a display device, comprising: (a) preparing an LED-equipped backplane having a backplane on which a first electrode and a second electrode are formed; a first connection pad formed on the first electrode; a second connection pad formed on the second electrode; a first light-emitting diode element mounted on the first connection pad; and a second light-emitting diode element mounted on the second connection pad; (b) inspecting the LED-equipped backplane by lighting up a plurality of light-emitting diode elements mounted on the LED-equipped backplane; (c) if, in step (b), there is a defective light-emitting diode element that does not light up, removing the defective light-emitting diode element; (d) if, in step (c), the connection pad on which the defective light-emitting diode element was mounted is also removed, forming a new connection pad on the electrode exposed after the removal of the connection pad, wherein step (d) comprises: (d1) preparing a stamp having a convex portion that is convex downwards; (d2) forming a connection material that will become the new connection pad at the lower end of the convex portion. (d3) A method for manufacturing a display device, comprising the step of lowering the stamp while a good light-emitting diode element is mounted, thereby positioning the connecting material formed on the lower end of the protrusion onto the electrode without interfering with the good light-emitting diode element.
2. In the method for manufacturing the display device according to claim 1, the amount of protrusion of the convex portion is greater than the thickness of the light-emitting diode element in the vertical direction.
3. A method for manufacturing a display device, comprising: (a) preparing an LED-equipped backplane having a backplane on which a first electrode and a second electrode are formed; a first connection pad formed on the first electrode; a second connection pad formed on the second electrode; a first light-emitting diode element mounted on the first connection pad; and a second light-emitting diode element mounted on the second connection pad; (b) inspecting the LED-equipped backplane by lighting up a plurality of light-emitting diode elements mounted on the LED-equipped backplane; (c) if, in step (b), there is a defective light-emitting diode element that does not light up, removing the defective light-emitting diode element; (d) if, in step (c), the connection pad on which the defective light-emitting diode element was mounted has also been removed, mounting a new light-emitting diode element on the electrode exposed by the removal of the connection pad via a new connection pad, wherein step (d) is: (d1) preparing a stamp having a convex portion that is convex downwards; A method for manufacturing a display device, comprising: (d2) holding the new light-emitting diode element, which has a connecting material forming the new connecting pad on its lower surface, with the protrusion; and (d3) with a good light-emitting diode element mounted, lowering the stamp so as not to interfere with the good light-emitting diode element, the new light-emitting diode element held by the protrusion and having the connecting material forming the new connecting pad on its lower surface, on the electrode.