A transparent LED display

Abstract

The application provides a transparent LED display screen, which comprises a transparent substrate and bare lamp beads; the bare lamp beads are arranged in an array on the transparent substrate; the transparent substrate is provided with a circuit pattern; the bare lamp beads comprise driving chips and light-emitting wafers; the light-emitting wafers are mounted on the driving chips; the circuit pattern comprises power supply pads, power supply lines and switching lines; the switching lines comprise switching jumpers and switching pads arranged on both sides of the bare lamp beads; the driving chips comprise a pair of power supply pins; the power supply pins comprise first power supply pins and second power supply pins; the first power supply pins and the second power supply pins on each bare lamp bead are respectively connected to the switching pads on both sides of the bare lamp bead through power supply jumpers. The application can effectively reduce the pixel pitch and effectively improve the resolution. The transparency of the transparent LED display screen can be further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of LED display, especially to the field of transparent LED display. BACKGROUND

[0002] Transparent LED display screen is gradually widely used in the market, and various product forms are developed. A transparent LED display screen technology of arraying LED lamp beads on a transparent substrate begins to appear. The existing transparent LED display screen is shown in the scheme Figure 1 、 Figure 2 , which comprises a transparent substrate 1', a printed circuit layer 3' provided on the transparent substrate 1', and LED lamp beads 2' with encapsulated driving chips arrayed on the transparent substrate 1'. Then a glue filling layer 5' is formed by filling glue on the surface of the transparent substrate 1' on which the LED lamp beads 2' are arranged. Then a protective cover plate 4' is covered on the surface of the glue filling layer 5'. The LED lamp beads 2' adopt the power supply circuit 6' shown in the figure to be directly connected to the electrode pin pad of the lamp bead welding area for power supply, wherein the power supply circuit 6' is divided into a positive power supply circuit 6a' and a negative power supply circuit 6b'. One positive power supply circuit 6a' and one negative power supply circuit 6b' are arranged on both sides of each column of LED lamp beads. And the LED lamp beads 2' are connected in series through the signal circuit 7' shown in the figure. The design of the power supply circuit 6' and the signal circuit 7' also reduces the transparency of the transparent LED display screen.

[0003] As shown in Figure 3 , the LED lamp beads 2' thereon are LED lamp beads 2' with encapsulated driving chips 21'; the LED lamp beads 2' comprise a shell 22', a driving chip 21', and red, green, and blue light emitting chips 20'; a chip mounting surface is formed on the shell 22', and a pin 23' is led out from the chip mounting surface; the driving chip 21' is mounted on the shell 22'; and the light emitting chip 20' is mounted on the driving chip 21'. The transparent LED display screen made of the LED lamp beads 2' with encapsulated driving chips 21' has high transparency, but due to the size constraint of the LED lamp beads 2', the general smaller encapsulation size is also 2.0 mm x 2.0 mm, and when the LED lamp beads 2' are arrayed and arranged with a pixel pitch of 5 mm x 5 mm or less, the size of the LED lamp beads 2' is relatively large, which obviously blocks the line of sight, and the transparent effect is not very ideal due to the dense arrangement of the power supply circuit and the signal circuit. If the resolution and the transparency are to be continuously improved, there is still a space for technical breakthrough. SUMMARY

[0004] In order to overcome the problems of low resolution and poor transparent effect of the transparent LED display screen with arrayed LED lamp beads in the prior art, the present application provides a transparent LED display screen.

[0005] The application provides a transparent LED display screen, comprising a transparent substrate and a naked lamp bead; a circuit pattern is arranged on the transparent substrate; the naked lamp beads are arranged in an array on the transparent substrate; the naked lamp bead comprises a driving chip and a light-emitting wafer; the light-emitting wafer is mounted on the driving chip;

[0006] The circuit pattern comprises a power supply pad, a power supply circuit and a switching circuit; the power supply circuit comprises a plurality of first power supply circuits and second power supply circuits with opposite polarities; the power supply pad is connected to the first power supply circuit and the second power supply circuit; the switching circuit comprises a switching jumper and a switching pad arranged on both sides of the naked lamp bead; the switching pad is directly or indirectly connected to the first power supply circuit and the second power supply circuit through the switching jumper;

[0007] The driving chip comprises a pair of power supply pins; wherein the power supply pins comprise a first power supply pin and a second power supply pin;

[0008] The first power supply pin and the second power supply pin on each naked lamp bead are respectively connected to the switching pads on both sides of the naked lamp bead through power supply jumpers.

[0009] Further, the circuit pattern further comprises a signal pad, and the driving chip further comprises a pair of signal pins; the signal pins comprise a first signal pin and a second signal pin;

[0010] The naked lamp bead is connected to the signal pad or the naked lamp beads before and after it through a signal jumper, so as to realize the series connection of the naked lamp beads and form a lamp bead string; and the control signal for controlling the on-off of each naked lamp bead can be input from the signal pad through the signal jumper and then transmitted through each series-connected naked lamp bead.

[0011] Further, the first power supply pin is arranged on one side edge of the driving chip, and the second power supply pin is arranged on the other side edge.

[0012] Further, the naked lamp bead is connected to the transparent substrate in a COG mode.

[0013] Further, the light-emitting wafer is mounted on the driving chip in a CSP or COC mode.

[0014] Further, the driving chip further comprises a pair of short-circuit pins, the pair of short-circuit pins comprising a short-circuit pin for inputting a signal and a short-circuit pin for outputting a signal; the pair of short-circuit pins are short-circuited inside the driving chip, so that the control signal is directly transmitted between the short-circuit pins without passing through the circuit inside the driving chip.

[0015] Further, each of the lamp bead strings is provided with two signal pads, respectively referred to as a first signal pad and a second signal pad.

[0016] In the lamp bead string, the signal pin of the input signal of the first bare lamp bead is connected to the first signal pad, and the short pin of the input signal of the first bare lamp bead is connected to the second signal pad.

[0017] Alternatively, the signal pin of the input signal of the first bare lamp bead is connected to the second signal pad, and the short pin of the input signal of the first bare lamp bead is connected to the first signal pad.

[0018] The signal pin of the input signal of each of the remaining bare lamp beads is connected to the short pin of the output signal of the previous bare lamp bead, and the short pin of the input signal of each of the bare lamp beads is connected to the signal pin of the output signal of the previous bare lamp bead; the signal pin of the output signal of each of the remaining bare lamp beads is connected to the short pin of the input signal of the next bare lamp bead, and the short pin of the output signal of each of the bare lamp beads is connected to the signal pin of the input signal of the next bare lamp bead.

[0019] Further, the power supply circuit includes a plurality of first power supply circuits and second power supply circuits arranged in rows or columns; a plurality of bare lamp beads are arranged between the first power supply circuits and the second power supply circuits; the first power supply circuits and the second power supply circuits are shared by the plurality of bare lamp beads arranged in rows or columns.

[0020] Further, the power supply circuit is a conductive grid or an ITO conductive film or a nano-silver film.

[0021] Further, the bare lamp beads are pasted on the conductive grid by an insulating die bonding method.

[0022] Further, a transparent substrate on which the bare lamp beads are arranged is provided with a glue filling layer, the glue filling layer encapsulating the bare lamp beads; an upper surface of the glue filling layer is provided with a protective cover plate.

[0023] Further, the transparent substrate is provided with a plurality of transparent unit plates; the bare lamp beads are arranged on the transparent unit plates; metal strips are arranged on both sides of each of the transparent unit plates as power supply circuits; the bare lamp beads on each of the transparent unit plates are connected to the power supply circuits.

[0024] Further, the adapter pads are mounted on the transparent substrate or the conductive grid by an insulating die bonding method.

[0025] Further, the power supply jumpers and the signal jumpers have a diameter of 15 μm-70 μm.

[0026] The proposed solution removes the housing from existing LED chips, retaining only the driver chip. A bare LED chip, without a housing, is then placed on the driver chip and replaced with this bare LED chip on a transparent substrate. This bare LED chip can be as small as 0.5mm x 0.7mm, significantly smaller than a standard LED chip. Therefore, it effectively reduces pixel pitch and greatly improves resolution. It can produce transparent LED displays with a pixel pitch of less than 3mm x 3mm. Even with a high-density pixel pitch of 2mm x 2mm, calculations show that over 80% transparency can be achieved, resulting in a very noticeable transparency effect. Power supply and signal transmission are achieved through jumper bonding. By selecting smaller diameter bonding wires, the overall obstruction of the view by conductive materials is reduced while ensuring the power supply and signal transmission of the bare LED beads. This further improves the transparency of the transparent LED display. At the same time, the driver chip on the bare LED bead has a pair of power pins, and adapter pads are set on the circuit pattern. The power pins are bonded through the adapter pads. In this way, each bare LED bead can independently draw power from the power supply line through the adapter line, improving the overall stability of the product. Attached Figure Description

[0027] Figure 1 This is a cross-sectional schematic diagram of a transparent LED display screen disclosed in the prior art;

[0028] Figure 2 This is a top view schematic diagram of a transparent LED display screen disclosed in the prior art;

[0029] Figure 3 This is a schematic diagram of an LED lamp bead disclosed in the prior art;

[0030] Figure 4 , Figure 5 This is a partial cross-sectional view of a transparent LED display screen from different angles, provided in a specific embodiment of this application.

[0031] Figure 6 This is a three-dimensional schematic diagram of the bare LED bead disclosed in the specific embodiments of this application;

[0032] Figure 7 This is a top view schematic diagram of the bare LED bead disclosed in the specific embodiments of this application;

[0033] Figure 8 This application provides a specific embodiment of a configuration with Figure 6 , Figure 7 A top view of a transparent LED display screen with bare LED chips;

[0034] Figure 9 yes Figure 8An enlarged schematic view of the middle A;

[0035] Figure 10 is a further preferred schematic view of the bare lamp bead provided in the specific embodiments of the present application;

[0036] Figure 11 is a transparent LED display screen provided in the specific embodiments of the present application, which is arranged with Figure 10 is a schematic view of the transparent LED display screen of the bare lamp bead from above;

[0037] Figure 12 is a further extension of the transparent LED display screen provided in the specific embodiments of the present application; Figure 11

[0038] Figure 13 is another setting of the transparent LED display screen provided in the specific embodiments of the present application; Figure 10 is a schematic view of the transparent LED display screen of the bare lamp bead from above;

[0039] Figure 14 is another setting of the transparent LED display screen provided in the specific embodiments of the present application; Figure 10 is a schematic view of the transparent LED display screen of the bare lamp bead from above;

[0040] Figure 15 is a partial sectional view of Figure 14 ;

[0041] Figure 16 is a further improved schematic view of the transparent LED display screen provided in the specific embodiments of the present application.

[0042] In the background art, the reference signs are as follows: 1', transparent substrate; 2', LED lamp bead; 3', printed circuit layer; 4', protective cover plate; 5', glue filling layer; 6', power supply circuit; 7', signal circuit; 6a', positive power supply circuit; 6b', positive power supply circuit; 20', light-emitting wafer; 21', driving chip; 22', shell; 23', pin;

[0043] ​Specific implementation method reference: 1, transparent substrate; 2, bare lamp bead; 3, circuit pattern; 4, protective cover plate; 5, glue layer; 6, transparent unit plate; 20, light emitting wafer; 21, driving chip; 20r, red light emitting wafer; 20g, green light emitting wafer; 20b, blue light emitting wafer; 211, signal pin; 212, first power supply pin; 213, second power supply pin; 214, short pin; 31, power supply circuit; 31a, first power supply circuit; 31b, second power supply circuit; 32, signal circuit; 33, signal pad; 311, power jumpers; 312, adapter pad; 313, adapter jumper; 312a, first adapter pad; 312b, second adapter pad; 321, signal jumper; 331, first signal pad; 332, second signal pad. Specific implementation

[0044] In order to make the technical problems solved by the application, the technical solutions and beneficial effects clearer, the application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the application and not to limit the application.

[0045] In the description of the application, it should be understood that the terms "longitudinal", "radial", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the application. In the description of the application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0046] In the description of the application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0047] Examples

[0048] This example will specifically explain the transparent LED display provided by the application, such as Figure 4 , Figure 5As shown, including transparent substrate 1 and bare lamp beads 2; the transparent substrate 1 is provided with circuit pattern 3; the bare lamp beads 2 are arrayed on the transparent substrate 1; as Figure 6 、 Figure 7 As shown, the bare lamp beads 2 include driving chip 21 and light-emitting wafer 20; the light-emitting wafer 20 is mounted on the driving chip 21; the bare lamp beads 2 in the present application cancel the packaging shell (English name is housing, Chinese also named as support or base) on the basis of the traditional LED lamp beads. The light-emitting wafer 20 mounted on the driving chip 21 does not need to be packaged again. The driving chip 21 with light-emitting wafer 20 is directly used as a light-emitting structure to replace the traditional LED lamp beads with a shell. That is, the bare lamp beads 2 in the present example is essentially the driving chip 21 embedded with light-emitting wafer 20.

[0049] The size of the bare lamp beads 2 ranges from 0.5mm x 0.5mm to 0.7mm x 0.7mm. It is much smaller than the traditional LED lamp beads. Therefore, the resolution of the transparent LED display screen can be effectively improved.

[0050] Preferably, a glue filling layer 5 is further provided on the transparent substrate 1 provided with the bare lamp beads 2, the glue filling layer 5 encapsulates each of the bare lamp beads 2 therein; the upper surface of the glue filling layer 5 is provided with a protective cover plate 4. The design of the glue filling layer 5 and the protective cover plate 4 is well known to those skilled in the art, and will not be described here.

[0051] As shown in Figure 6 、 Figure 7As shown, the driving chip 21 is known to the public, and generally has a driving circuit integrated inside the driving chip 21, and a passivation layer is provided on the driving chip 21, which is a surface insulating layer formed when the driving chip 21 is manufactured. The driving chip 21 is provided with a plurality of pins, and the technology of mounting the light-emitting wafer 20 on the driving chip 21 is known to the public, and generally uses CSP or COC technology to be fixedly mounted on the driving chip 21, and the pins on the driving chip 21 are electrically connected with the light-emitting wafer 20 through direct welding or through bonding wires. The bonding wire, also known as the binding wire, usually includes gold wire, copper wire, palladium-plated copper wire, and alloy wire, etc. No further description is given. The pin (English name: PAD) is generally provided on the passivation layer, and the pin is a terminal inside the chip. The driving chip 21 includes a pair of signal pins 211 and a pair of power pins; wherein the signal pins 211 include a first signal pin and a second signal pin; the power pins include a first power pin 212 and a second power pin 213, respectively; as shown in the figure, the driving chip 21 is divided into upper, lower, left and right directions; it can be seen that one pair of signal pins 211 is respectively arranged at the right upper corner and the left lower corner of the driving chip 21; and one pair of power pins is respectively arranged at the left upper corner and the right lower corner. In this example, as a preferred mode, the above-mentioned light-emitting wafer 20 includes three kinds of red, green and blue light-emitting wafers 20, which are respectively referred to as a first light-emitting wafer, a second light-emitting wafer and a third light-emitting wafer; wherein the first light-emitting wafer is a red light-emitting wafer 20r, the second light-emitting wafer is a green light-emitting wafer 20g, and the third light-emitting wafer is a blue light-emitting wafer 20b. As shown in the figure, the red light-emitting wafer 20r, the green light-emitting wafer 20g and the blue light-emitting wafer 20b are sequentially mounted on the driving chip 21.

[0052] Among them, the input and output of the above-mentioned signal pin 211 are opposite, for example, the first signal pin is a signal input pin, and the second signal pin is a signal output pin. Conversely, the first signal pin is a signal output pin, and the second signal pin is a signal input pin. As a preferred mode, the two signal pins 211 can be switched with each other. One of the two signal pins 211 serves as a signal input pin, and the other serves as a signal output pin. As a preferred scheme, the bare lamp bead 2 is preferably a bidirectional transmission bare lamp bead. The first signal pin of the bidirectional transmission bare lamp bead is an input signal pin, and the second signal pin is an output signal pin; conversely, the second signal pin of the bidirectional transmission bare lamp bead 2 is an input signal pin, and the first signal pin is an output signal pin. By using such a bidirectional transmission bare lamp bead, bidirectional input signals of the bare lamp bead 2 can be realized and transmitted when the bare lamp bead 2 is connected in series. The bidirectional transmission scheme is the original technology of the applicant, and the applicant has already patented the driving chip 21 and the lamp bead for bidirectional transmission (for details, please refer to CN111341247A). In this example, the bidirectional transmission scheme can be directly quoted. No further description is given.

[0053] As shown in Figure 8 , Figure 9 , the circuit pattern 3 includes a power supply pad (not shown in the figure), a signal pad 33, a power supply line 31 and a switching line; the power supply line 31 includes a plurality of first power supply lines 31a and second power supply lines 31b with opposite polarities; the power supply pad is connected to the first power supply line 31a and the second power supply line 31b; in this example, only one first power supply line 31a and one second power supply line 31b are shown, but the number of the above-mentioned power supply lines 31 can be further increased. It can make several rows or columns share the above-mentioned first power supply line 31a and second power supply line 31b. The switching line includes a switching jumper 313 and a switching pad 312 arranged on both sides of the bare lamp bead 2; the switching pad 312 is directly or indirectly electrically connected to the first power supply line 31a and the second power supply line 31b through the switching jumper 313;

[0054] Among them, the bare lamp bead 2 is bound to the signal pad 33 or the bare lamp beads 2 in front and behind it through a signal line 32 (in this application, it is specifically a signal jumper 321) to realize the series connection of the bare lamp beads 2 and form a lamp bead string; so that the control signal for controlling the on-off of each bare lamp bead 2 can be input from the signal pad 33 through the signal jumper 321 and then transmitted through each series-connected bare lamp bead 2 in turn;

[0055] The first power supply pin 212 and the second power supply pin 213 on each bare lamp bead 2 are bound to the switching pads 312 on both sides of the bare lamp bead 2 through power supply jumpers 311.

[0056] In this example, one side of the driving chip 21 is provided with a first power supply pin 212, and the other side is provided with a second power supply pin 213. The side is a relative concept, for example, the first power supply pin 212 is arranged on the left side of the driving chip 21, and the second power supply pin 213 is arranged on the right side of the driving chip 21. Conversely, it is also possible. In this example, two switching pads 312 are arranged on the left upper corner and the right lower corner of each bare lamp bead 2, of course, they can also be arranged on the upper and lower sides or the left and right sides of the bare lamp bead 2, which are all possible.

[0057] It should be noted that the signal transmission in this example does not necessarily have to be realized through the signal pad, the signal line and each bare lamp bead, and other implementation methods are also possible, such as transmitting signals through the power supply line. It is also possible to transmit signals through the power supply line based on the current technology. In this example, the way of series connection of each bare lamp bead through the signal pad and the signal jumper is the preferred way.

[0058] As shown in Figure 8As shown in the figure, in one aspect, the transfer pads 312 in the transfer lines are connected to the first power supply line 31a or the second power supply line 31b through the transfer jumper 313, so that the transfer lines with opposite polarities are formed on the upper and lower sides of each row of bare lamp beads 2. Specifically, the transfer pads are named as the first transfer pad and the second transfer pad, respectively, as shown in the figure. Figure 9 As shown in the figure, the first transfer pad 312a is arranged at the upper part of the bare lamp bead 2, and the second transfer pad 312b is arranged at the lower part of the bare lamp bead 2. The transfer line with the first transfer pad 312a at the upper part is called the first transfer line, and the transfer line with the second transfer pad 312b at the lower part is called the second transfer line. The first transfer line is connected to the first power supply line 31a, and the second transfer line is connected to the second power supply line 31b. The first power supply pin 212 and the second power supply pin 213 on each bare lamp bead 2 are connected to the first transfer pad 312a and the second transfer pad 312b, respectively, that is, the purpose of taking power from the first power supply line 31a and the second power supply line 31b by each bare lamp bead 2 is achieved.

[0059] The power jumper 311 and the signal jumper 321 and the transfer jumper 313 in the example are the binding wires or bonding wires understood by those skilled in the art. Here, only to distinguish the devices, they are named respectively. The power jumper 311 and the signal jumper 321 described above are preferably gold wires, copper wires or alloy wires with a diameter of 15 μm-70 μm. Since the diameter is very small, it is almost invisible to the naked eye. Therefore, while ensuring that the working current of the connected several bare lamp beads 2 is met, the obstruction to the line of sight is reduced, and the transparency of the product is improved.

[0060] The transfer pad in the example can be as small as 0.1 mm x 0.3 mm. It can be formed when the circuit pattern 3 is made on the transparent substrate 1, or it can be bound on the transparent substrate 1 by die bonding.

[0061] In the example, as to the mounting mode of the light-emitting wafer 20, it is preferred that the light-emitting wafer 20 is mounted on the driving chip 21 by the CSP (Chip Scale Package, Chip Scale Package) mode. It can also be mounted on the driving chip 21 by the COC (Chip On Chip, Chip On Chip) mode.

[0062] Preferably, after the light-emitting wafer 20 is mounted on the driving chip 21, the bare lamp bead 2 is mounted on the transparent substrate 1 as a whole, which is conducive to improving the process efficiency and yield.

[0063] In this example, the bare lamp beads 2 are connected to the transparent substrate 1 by COG (chip on glass) method. COG method means that the chip is directly bonded on the transparent substrate. This is well known to those skilled in the art. No further description is given.

[0064] Applicants found in the research and development process that, at present, due to the objective fact of signal attenuation in the signal transmission process, the number of LED lamp beads 2 in the stringing process is too large, and the display effect will decrease. In the ideal state, the number of LED lamp beads 2 in a lamp string is generally controlled within 384. This greatly reduces the size of the LED transparent display screen.

[0065] As a preferred mode, as shown in Figure 10 The driving chip 21 also includes a pair of short-circuit pins 214, which include a short-circuit pin 214 for input signal and a short-circuit pin 214 for output signal; the pair of short-circuit pins 214 are short-circuited inside the driving chip 21, so that the control signal is directly transmitted between the short-circuit pins 214 without passing through the circuit inside the driving chip 21.

[0066] As a preferred mode, two signal pads 33 are provided for each lamp bead string, which are respectively referred to as first signal pad 331 and second signal pad 332.

[0067] In the lamp bead string, the signal pin 211 of the input signal of the first bare lamp bead 2 is connected to the first signal pad 331, and the short-circuit pin 214 of the input signal of the first bare lamp bead 2 is connected to the second signal pad 332.

[0068] Alternatively, the signal pin 211 of the input signal of the first bare lamp bead 2 is connected to the second signal pad 332, and the short-circuit pin 214 of the input signal of the first bare lamp bead 2 is connected to the first signal pad 331.

[0069] The signal pin 211 of the input signal of each of the remaining bare lamp beads 2 is connected to the short-circuit pin 214 of the output signal of the previous bare lamp bead 2, and the short-circuit pin 214 of the input signal of each of the bare lamp beads 2 is connected to the signal pin 211 of the output signal of the previous bare lamp bead 2; the signal pin 211 of the output signal of each of the remaining bare lamp beads 2 is connected to the short-circuit pin 214 of the input signal of the next bare lamp bead 2, and the short-circuit pin 214 of the output signal of each of the bare lamp beads 2 is connected to the signal pin 211 of the input signal of the next bare lamp bead 2.

[0070] In this way, a single LED string can be transformed into two LED strings controlled by two control signals. For example, the odd-numbered bare LEDs 2 in the LED string transmit control signals from the first signal pad 331; the even-numbered bare LEDs 2 in the LED string transmit control signals from the second signal pad 332; and vice versa. Due to this special bonding connection method, the two signals from the first signal pad 331 and the second signal pad 332 are always transmitted in adjacent bare LEDs 2 or short-circuited so that they do not pass through the interior of those bare LEDs 2.

[0071] Further description is as follows: Let the control signal input to the first signal pad 331 be the first control signal, and the control signal input to the second signal pad 332 be the second control signal; then... Figure 11 As shown, taking the first row of bare LED beads 2 as an example, the first signal pad 331 is bonded to the shorting pin 214 of the input signal of the first row of bare LED beads 2; the second signal pad 332 is bonded to the signal pin 211 of the input signal of the first row of bare LED beads 2, so that the first control signal transmitted in the first signal pad 331 is shorted in the first row of bare LED beads 2 to the signal pin 211 of the input signal of the first row of bare LED beads 2, without passing through the inside of the first row of bare LED beads 2; so that the second control signal transmitted in the second signal pad 332 passes through the first row of bare LED beads 2, and the second control signal controls the lighting of the first row of bare LED beads 2, and is transmitted to the shorting pin 214 of the input signal of the first row of bare LED beads 2. Similarly, the first control signal for the bare LEDs 2 in the second row of the first column is input through the signal pin 211 of the input signal, controlling the on / off state of the bare LEDs 2 in the second row of the first column. The signal is then output from the signal pin 211 of the output signal to the shorting pin 214 of the input signal for the bare LEDs 2 in the third row of the first column. The second control signal is shorted out of the bare LEDs 2 in the second row of the first column. This process continues, with the first control signal passing through the bare LEDs 2 in even-numbered rows, controlling their on / off state, and being shorted out of the bare LEDs 2 in odd-numbered rows. The second control signal passes through the bare LEDs 2 in odd-numbered rows, controlling their on / off state, and is shorted out of the bare LEDs 2 in even-numbered rows. The reverse is also possible.

[0072] This method increases the number of bare LED chips connected in series in a row or column of LED strings. The number of bare LED chips in the string is twice that of a conventional LED string.

[0073] Preferably, the power supply lines 31 comprise a plurality of the first power supply lines 31a and the second power supply lines 31b arranged in rows or columns; a plurality of the bare lamp beads 2 are arranged between the first power supply lines 31a and the second power supply lines 31b; the bare lamp beads 2 arranged in the plurality of rows or columns share the first power supply lines 31a and the second power supply lines 31b.

[0074] The power supply lines 31 comprise a plurality of the first power supply lines 31a and the second power supply lines 31b arranged in rows or columns; a plurality of the bare lamp beads 2 are arranged between the first power supply lines 31a and the second power supply lines 31b; the bare lamp beads 2 arranged in the plurality of rows or columns share the first power supply lines 31a and the second power supply lines 31b. For example, as shown in the figure, the first power supply lines 31a, the second power supply lines 31b and the first power supply lines 31a are arranged in rows or columns; the first power supply lines 31a and the second power supply lines 31b on the left side are arranged between four rows and four columns of the bare lamp beads 2; the four rows and four columns of the bare lamp beads 2 share the first power supply lines 31a and the second power supply lines 31b. The first power supply lines 31a and the second power supply lines 31b on the right side are also arranged between four rows and four columns of the bare lamp beads 2; the four rows and four columns of the bare lamp beads 2 share the first power supply lines 31a and the second power supply lines 31b. Figure 12

[0075] In the above manner, a plurality of columns or a plurality of rows of the bare lamp beads 2 share the power supply lines 31 of the same polarity, and such a cyclic arrangement can be used to make a large-area transparent LED display screen. The sharing of the power supply lines 31 by a plurality of bare lamp beads 2 can reduce the number of power supply lines 31, reduce the obstruction of the line of sight, and help improve the transparency of the display screen.

[0076] Although the power supply jumpers 311 and the signal jumpers 321 are crossed in the schematic diagram, they are actually connected by wire bonding at different heights and then fixed by glue filling, so there is no risk of short circuit caused by collapse.

[0077] The present application is not limited to the implementation of the power supply lines 31, which is not the core innovative content of the present application, and can use the implementation known to those skilled in the art. The number of the first power supply lines 31a and the second power supply lines 31b can be one or more, and the number of the first power supply lines 31a and the second power supply lines 31b can be the same or different. The specific number is determined according to the power supply capacity of the power supply lines 31 and the current demand of the bare lamp beads 2 between the first power supply lines 31a and the second power supply lines 31b.

[0078] ​The power supply line 31 can be in the form of a straight line, a curved line, a serpentine line segment, etc. As a preferred mode, each power supply line 31 is generally arranged in a row or column, and the implementation is not limited, as long as it can provide power supply power. For example, it can be a metal layer etched on the transparent substrate 1, or a metal mesh, or a nano-silver coating or ITO coating, or a metal wire or a metal sheet embedded in the transparent substrate 1 as laid out in the patent previously applied by the applicant.

[0079] As a preferred mode, as shown in Figure 13 , the power supply line 31 is preferably a conductive mesh. The conductive mesh can be a metal mesh or ITO, and the dots in the figure are the binding lines and the binding points (electrical connection points) of the metal mesh or ITO. The metal mesh or ITO has a large square resistance and a small conductive capacity, so a large area is needed to meet the current demand. In the figure, the conductive mesh is arranged on both sides of several columns of bare lamp beads 2, and the bare lamp beads 2 between the first power supply line 31a and the second power supply line 31b in the form of a conductive mesh share the first power supply line 31a and the second power supply line 31b. At this time, only the bare lamp beads 2 need to be fixed on the glass substrate.

[0080] As shown in Figure 14 , Figure 15 , in order to enhance the conductive capacity of the conductive mesh, the area of the conductive mesh can also be expanded, and then the bare lamp beads 2 and the adapter pads 312 are installed on the conductive mesh, but at this time, the bare lamp beads 2 need to be insulated from the conductive mesh. That is, the bare lamp beads 2 are bound to the metal mesh by insulating die bonding, and the driving chip 21 and the conductive mesh are firmly bonded by insulating die bonding glue. For example, the two columns of bare lamp beads 2 on the left in the figure are arranged on the conductive mesh of the first power supply line 31a, and the two columns of bare lamp beads 2 on the right in the figure are arranged on the conductive mesh of the second power supply line 31b. The adapter pads 312 are also mounted on the transparent substrate 1 or the conductive mesh in an insulating die bonding manner.

[0081] As for the design of the power supply line 31, there can also be other forms of variations, for example, as shown in Figure 16As shown, a plurality of transparent unit plates 6 are arranged on the transparent substrate 1; the bare lamp beads 2 are arranged on the transparent unit plates 6; metal strips are arranged on both sides of each transparent unit plate 6 as power supply lines 31; the bare lamp beads 2 on each transparent unit plate 6 are connected to the power supply lines 31. The power supply lines 31 on both sides are respectively a first power supply line 31a and a second power supply line 31b. In this way, the transparent substrate 1 surface is free of power supply lines 31, but is embedded between two transparent unit plates 6. The transparent unit plates 6 are mutually independent glass plates, and each transparent unit plate 6 is fixed on the lower whole transparent substrate 1. The advantage of this way is that the cross-sectional area of the metal strip in the screen viewing direction is very small, which can ensure sufficient current supply between the two power supply lines with opposite polarities and a plurality of bare lamp beads 2, greatly reducing the obstruction of conductive materials to the line of sight, and improving the transparency of the screen.

[0082] By adopting the scheme, the shell in the existing LED lamp bead is removed, only the driving chip 21 is reserved, the light-emitting wafer 20 is arranged on the driving chip 21 to form the bare lamp bead 2 without a shell, the bare lamp bead 2 is arranged on the transparent substrate 1 to replace the existing LED lamp bead array, and the size of the bare lamp bead 2 is much smaller than that of the LED lamp bead. Therefore, the pixel pitch can be effectively reduced, the resolution can be effectively improved, a transparent LED display screen with a pitch smaller than 3 mm x 3 mm can be manufactured, the power supply and signal transmission are realized in a way of binding by a jumper, a binding wire with a smaller diameter is selected, the obstruction of the conductive material to the line of sight is reduced as a whole under the condition of ensuring the power supply and signal transmission of the bare lamp bead, and therefore the transparency of the transparent LED display screen can be further improved. Since the diameter of the jumper is extremely small, the copper wire with a diameter of 15 μm-70 μm can be preferably selected, the current is ensured, and the line of sight is almost not affected, and therefore even under the condition of a pitch of 2 mm x 2 mm, the screen can have a transparency of more than 80%, and the transparent effect is very obvious. Meanwhile, a pair of power supply pins are arranged on the driving chip 21 of the bare lamp bead 2, and a switching pad 312 is arranged on the circuit pattern 3, the power supply pins are connected by the switching pad 312, and in this way, each bare lamp bead 2 can independently take power from the power supply line 31 through the switching line, and the overall stability of the product is improved.

[0083] The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A transparent LED display screen, characterized in that, The device includes a transparent substrate and bare LED beads; a circuit pattern is arranged on the transparent substrate; an array of bare LED beads is arranged on the transparent substrate; each bare LED bead includes a driver chip and a light-emitting chip; a passivation layer is provided on the driver chip; and the light-emitting chip is mounted on the driver chip. The circuit pattern includes power pads, power supply lines, and adapter lines; the power supply lines include several first power supply lines and second power supply lines with opposite polarities. The power pad connects the first power supply line and the second power supply line; The adapter line includes an adapter jumper and adapter pads arranged on both sides of the bare LED bead; the adapter pads are directly or indirectly connected to the first power supply line and the second power supply line through the adapter jumper. The driver chip includes a pair of power pins; the power pins include a first power pin and a second power pin. The first power pin and the second power pin on each of the bare LED chips are respectively connected to the adapter pads on both sides of the bare LED chip via power jumpers; The circuit pattern also includes signal pads, and the driver chip also includes a pair of signal pins; the signal pins include a first signal pin and a second signal pin; The bare LEDs are connected to signal pads or bare LEDs before and after them via signal jumpers to achieve series connection of the bare LEDs and form a string of LEDs; so that the control signal for controlling the on / off state of each bare LED can be input from the signal pads via the signal jumpers and then transmitted sequentially through each series of bare LEDs. The driver chip also includes a pair of shorting pins, which include a shorting pin for input signals and a shorting pin for output signals; the pair of shorting pins are shorted inside the driver chip, so that the control signal is transmitted directly from the shorting pins without passing through the internal circuitry of the driver chip. Each LED string has two signal pads, referred to as the first signal pad and the second signal pad respectively; In the LED string, the signal pin of the input signal of the first bare LED is connected to the first signal pad, and the shorting pin of the input signal of the first bare LED is connected to the second signal pad. Alternatively, the signal pin of the input signal of the first bare LED bead is connected to the second signal pad, and the shorting pin of the input signal of the first bare LED bead is connected to the first signal pad. The input signal pins of the remaining bare LEDs are connected to the shorting pins of the output signal of the previous bare LED, and the shorting pins of the input signals of each bare LED are connected to the signal pins of the output signal of the previous bare LED; the output signal pins of the remaining bare LEDs are connected to the shorting pins of the input signal of the next bare LED, and the shorting pins of the output signal of each bare LED are connected to the signal pins of the input signal of the next bare LED.

2. The transparent LED display screen according to claim 1, characterized in that, The driver chip has a first power pin on one side and a second power pin on the other side.

3. The transparent LED display screen according to claim 1, characterized in that, The bare LED beads are bonded to the transparent substrate using a COG method.

4. The transparent LED display screen according to claim 1, characterized in that, The light-emitting chip is mounted on the driver chip via CSP or COC.

5. The transparent LED display screen according to claim 1, characterized in that, The power supply line includes a plurality of first power supply lines and second power supply lines arranged in rows or columns; a plurality of rows or columns of bare LED beads are provided between the first power supply lines and the second power supply lines; the plurality of rows or columns of bare LED beads provided between the first power supply lines and the second power supply lines share the first power supply lines and the second power supply lines.

6. The transparent LED display screen according to claim 1, characterized in that, The power supply line is a conductive mesh, an ITO conductive film, or a nano-silver thin film.

7. The transparent LED display screen according to claim 6, characterized in that, The power supply line is a conductive grid, and the bare LED beads are fixed on the conductive grid by an insulating die bonding method.

8. The transparent LED display screen according to claim 1, characterized in that, A potting layer is provided on a transparent substrate on which the bare LED beads are arranged, and the potting layer encapsulates each of the bare LED beads therein; The upper surface of the potting layer is provided with a protective cover plate.

9. The transparent LED display screen according to claim 8, characterized in that, The transparent substrate is provided with a plurality of transparent unit boards; the bare LED beads are arranged on the transparent unit boards; metal strips are provided on both sides of each transparent unit board as power supply lines; the bare LED beads on each transparent unit board are connected to the power supply lines.

10. The transparent LED display screen according to claim 7, characterized in that, The adapter pads are mounted on the transparent substrate or on the conductive mesh using an insulating die bond method.

11. The transparent LED display screen according to claim 1, characterized in that, The diameter of the power jumper and the signal jumper is 15μm-70μm.

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