Multi-channel visible light communication system

Abstract

A multi-channel visible light communication system includes a carrier plate and a plurality of light emitting element stacks. The light-emitting element stacks are arranged on the carrier plate, wherein each of the light-emitting element stacks comprises a first light-emitting element, a second light-emitting element and a first adhesive layer. The second light emitting element is on the first light emitting element. The first adhesive layer is arranged between the first light-emitting element and the second light-emitting element, the first adhesive layer comprises a first metasurface, and the first metasurface is configured to enable first color light emitted by the first light-emitting element to pass through and reflect second color light emitted by the second light-emitting element. The number of channels of the multi-channel visible light communication system can cover the visible light range so as to increase the transmission capacity and the transmission rate.

Description

Technical Field

[0001] Some embodiments of the present disclosure relate to a multi-channel visible light communication system. Background Art

[0002] Visible light communication is one of the most common communication methods. It can avoid the interference of electromagnetic waves from general wireless local area networks (WLAN) or high-frequency wireless transmission on the human body and surrounding electronic devices, and has high security. Common visible light communication systems can use light-emitting elements (such as light-emitting diodes, LEDs, etc.) as light sources to transmit signals. How to improve the transmission rate and capacity of visible light communication systems is one of the research focuses in this field. Summary of the invention

[0003] Some embodiments of the present disclosure include a multi-channel visible light communication system, including a substrate and a plurality of light-emitting element stacks. The light-emitting element stacks are arranged on the substrate, wherein each of the light-emitting element stacks includes a first light-emitting element, a second light-emitting element, and a first adhesive layer. The second light-emitting element is on the first light-emitting element. The first adhesive layer is between the first light-emitting element and the second light-emitting element, wherein the first adhesive layer includes a first metasurface, and the first metasurface is configured to allow a first color light emitted by the first light-emitting element to pass through and reflect a second color light emitted by the second light-emitting element.

[0004] In some embodiments, each of the light-emitting element stacks further includes a third light-emitting element and a second adhesive layer. The third light-emitting element is on the second light-emitting element. The second adhesive layer is between the second light-emitting element and the third light-emitting element, wherein the second adhesive layer includes a second metasurface, and the second metasurface is configured to allow the first color light emitted by the first light-emitting element and the second color light emitted by the second light-emitting element to pass through and reflect the third color light emitted by the third light-emitting element.

[0005] In some embodiments, the first light emitting element, the second light emitting element, and the third light emitting element of each of the light emitting element stacks can be independently controlled.

[0006] In some embodiments, the second adhesive layer of each light emitting device stack further includes a refractive index matching layer covering the second metasurface.

[0007] In some embodiments, the second adhesive layer of each of the light emitting device stacks further comprises a distributed Bragg reflector below the second metasurface.

[0008] In some embodiments, the wavelength of the first color light emitted by the first light emitting element is greater than the wavelength of the second color light emitted by the second light emitting element, and the wavelength of the second color light emitted by the second light emitting element is greater than the wavelength of the third color light emitted by the third light emitting element.

[0009] In some embodiments, the first light emitting element is a red light emitting element, the second light emitting element is a green light emitting element, and the third light emitting element is a blue light emitting element.

[0010] In some embodiments, the first adhesive layer of each light emitting device stack further includes a refractive index matching layer covering the first metasurface.

[0011] In some embodiments, the refractive index matching layer is made of an organic glue.

[0012] In some embodiments, the first adhesive layer of each of the light emitting element stacks further comprises a distributed Bragg reflector below the first metasurface.

[0013] In summary, some embodiments of the present disclosure provide a multi-channel visible light communication system, wherein the number of channels in the multi-channel visible light communication system may cover the number of channels in the visible light range, so as to increase the transmission capacity and rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A three-dimensional diagram of a multi-channel visible light communication system according to some embodiments of the present disclosure is shown.

[0015] Figure 2 Draw Figure 1 Exploded view of the stack of light-emitting components.

[0016] Figure 3 Some embodiments of the present disclosure are shown in FIG. Figure 2 Exploded view of the first adhesive layer.

[0017] Figure 4 In some other embodiments of the present disclosure, Figure 2 Exploded view of the first adhesive layer.

[0018] Figure 5A , Figure 5B and Figure 5C Schematic diagrams are respectively shown of using a first adhesive layer and a second adhesive layer to filter a first color light, a second color light, and a third color light according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0019] Some embodiments of the present disclosure provide a multi-channel visible light communication system. The number of channels in the multi-channel visible light communication system can cover the number of channels in the visible light range to increase the transmission capacity and rate. Specifically, the light-emitting elements in the multi-channel visible light communication system can be stacked vertically so that the multi-channel visible light communication system can accommodate more light-emitting elements, and the light-emitting elements in each light-emitting element stack can be independently controlled to mix any color light, so that any color light can cover the complete visible light range.

[0020] Figure 1 A three-dimensional diagram of a multi-channel visible light communication system 100 according to some embodiments of the present disclosure is shown. The multi-channel visible light communication system 100 includes a carrier 200 and a plurality of light emitting device stacks 300 .

[0021] The carrier 200 is a carrier including a driving circuit, and the driving circuit can be used to drive the light emitting element stack 300 arranged on the carrier 200. In some embodiments, the carrier 200 can be made of a common semiconductor circuit substrate (silicon (Si), glass, etc.).

[0022] The light emitting element stack 300 is arranged on the carrier 200. The light emitting element stack 300 can be arranged in an array. For example, the light emitting element stack 300 can be arranged along a first direction X and a second direction Y. Each of the light emitting element stacks 300 includes a first light emitting element 310, a first adhesive layer 320, a second light emitting element 330, a second adhesive layer 340 and a third light emitting element 350 that are vertically stacked. That is, the first light emitting element 310, the first adhesive layer 320, the second light emitting element 330, the second adhesive layer 340 and the third light emitting element 350 of each of the light emitting element stacks 300 are arranged along the Z direction. Since the first light emitting element 310, the second light emitting element 330 and the third light emitting element 350 in the present disclosure are vertically stacked, the multi-channel visible light communication system 100 can accommodate more light emitting elements per unit area. It should be noted that although Figure 1 Only four light emitting element stacks 300 are shown, but there are actually more light emitting element stacks 300. In some embodiments, the number of light emitting element stacks 300 arranged in the first direction X and the second direction Y can reach thousands, so the total number of light emitting element stacks 300 of the multi-channel visible light communication system 100 can reach millions.

[0023] Figure 2 Draw Figure 1 Exploded view of a light emitting element stack 300. Each of the light emitting element stacks 300 includes a first light emitting element 310, a first adhesive layer 320, a second light emitting element 330, a second adhesive layer 340, and a third light emitting element 350. The second light emitting element 330 is on the first light emitting element 310, and the third light emitting element 350 is on the second light emitting element 330. The first adhesive layer 320 is between the first light emitting element 310 and the second light emitting element 330 to provide adhesion between the first light emitting element 310 and the second light emitting element 330. The second adhesive layer 340 is between the second light emitting element 330 and the third light emitting element 350 to provide adhesion between the second light emitting element 330 and the third light emitting element 350.

[0024] The first light-emitting element 310 includes a chip 312 and a conductive pad 314. The chip 312 of the first light-emitting element 310 can be any suitable light-emitting chip, such as a light-emitting diode chip, a micro-light-emitting diode chip, an organic light-emitting diode chip, a semiconductor laser chip or the like. The chip 312 of the first light-emitting element 310 is used to emit a first color light. The conductive pads 314 of the first light-emitting element 310 can be located on both sides of the chip 312, and can be used to electrically connect the first light-emitting element 310 to the carrier 200 through wiring (not shown). Specifically, one of the conductive pads 314 is connected to the driving circuit in the carrier 200, and the other conductive pad 314 is connected to the ground electrode in the carrier 200.

[0025] The second light emitting element 330 includes a chip 332 and a conductive pad 334. The chip 332 of the second light emitting element 330 may be any suitable light emitting chip, such as a light emitting diode chip, a micro light emitting diode chip, an organic light emitting diode chip, a semiconductor laser chip or the like. The chip 332 of the second light emitting element 330 is used to emit a second color light. The conductive pads 334 of the second light emitting element 330 may be located on both sides of the chip 332, and may be used to electrically connect the second light emitting element 330 to the carrier 200 through wiring (not shown). Specifically, one of the conductive pads 334 is connected to the driving circuit in the carrier 200, and the other conductive pad 334 is connected to the ground electrode in the carrier 200.

[0026] The third light emitting element 350 includes a chip 352 and a conductive pad 354. The chip 352 of the third light emitting element 350 may be any suitable light emitting chip, such as a light emitting diode chip, a micro light emitting diode chip, an organic light emitting diode chip, a semiconductor laser chip or the like. The chip 352 of the third light emitting element 350 is used to emit a third color light. The conductive pads 354 of the third light emitting element 350 may be located on both sides of the chip 352, and may be used to electrically connect the third light emitting element 350 to the carrier 200 through wiring (not shown). Specifically, one of the conductive pads 354 is connected to the driving circuit in the carrier 200, and the other conductive pad 354 is connected to the ground electrode in the carrier 200.

[0027] The first light emitting element 310, the second light emitting element 330 and the third light emitting element 350 emit a first color light, a second color light and a third color light respectively. The wavelength of the first color light emitted by the first light emitting element 310 is greater than the wavelength of the second color light emitted by the second light emitting element 330, and the wavelength of the second color light emitted by the second light emitting element 330 is greater than the wavelength of the third color light emitted by the third light emitting element 350. That is, the wavelengths of the color lights emitted by the first light emitting element 310, the second light emitting element 330 and the third light emitting element 350 decrease from bottom to top. In some embodiments, the first light emitting element 310 is a red light emitting element, the second light emitting element 330 is a green light emitting element, and the third light emitting element 350 is a blue light emitting element. In some embodiments of the present disclosure, the first light emitting element 310 directly emits the first color light, the second light emitting element 330 directly emits the second color light, and the third light emitting element 350 directly emits the third color light, and the first color light, the second color light and the third color light are each a color light of different wavelength bands. Therefore, the light emitting device stack 300 does not need an additional wavelength conversion layer to convert the wavelength of the color light, thereby reducing the energy loss of the color light passing through the wavelength conversion layer.

[0028] The conductive pad 314 of the first light-emitting element 310, the conductive pad 334 of the second light-emitting element 330 and the conductive pad 354 of the third light-emitting element 350 are independently arranged. That is, there is no electrical connection between the conductive pad 314 of the first light-emitting element 310, the conductive pad 334 of the second light-emitting element 330 and the conductive pad 354 of the third light-emitting element 350. Therefore, the conductive pad 314 of the first light-emitting element 310, the conductive pad 334 of the second light-emitting element 330 and the conductive pad 354 of the third light-emitting element 350 can be independently connected to different driving circuits. In this way, the first light-emitting element 310, the second light-emitting element 330 and the third light-emitting element 350 can be independently controlled, thereby achieving an "addressable" multi-channel visible light communication system 100. "Addressable" here means that a specific light-emitting element can be specified in the first direction X, the second direction Y, and the third direction Z to control the brightness of the light-emitting element without affecting the control of other light-emitting elements. Since the first light-emitting element 310, the second light-emitting element 330 and the third light-emitting element 350 of each of the light-emitting element stack 300 can be independently controlled, high-degree-of-freedom wavelength control can be achieved, so that the light emitted by the light-emitting element stack 300 can be mixed into any color light. Specifically, the switch or intensity of the first color light, the second color light and the third color light can be controlled to cause different composition ratios of the first color light, the second color light and the third color light. When the intensities of the first color light, the second color light and the third color light are different, a function similar to amplitude modulation can be achieved to mix any color light. Different colors of light can represent different channels, so the number of channels covering the entire visible light range can be designed. Compared with the original number of channels (three channels represented by the first color light, the second color light and the third color light), the transmission capacity and rate of the multi-channel visible light communication system 100 can be greatly increased.

[0029] The first adhesive layer 320 includes a first metasurface 322 and a refractive index matching layer 324 . Figure 3 Some embodiments of the present disclosure are shown in FIG. Figure 2FIG. 1 is an exploded view of the first adhesive layer 320 of FIG. The first metasurface 322 of the first adhesive layer 320 may include a substrate 322A and a plurality of antennas 322B. The antennas 322B are protrusions protruding upward from the substrate 322A. The antennas 322B may be designed to have different widths and arrangement periods so that the first color light emitted by the first light-emitting element 310 passes through and reflects the second color light emitted by the second light-emitting element 330. The refractive index matching layer 324 covers the first metasurface 322, for example, covers the upper surface and all side surfaces of the antennas 322B. The refractive index matching layer 324 may also fill the gaps between the antennas 322B. In some embodiments, the refractive index matching layer 324 may also be coated on the substrate 322A of the first metasurface 322. The refractive index matching layer 324 may be used to improve the optical performance between the first light-emitting element 310 and the first adhesive layer 320. For example, if the refractive index matching layer 324 is not provided, when the first color light emitted by the first light emitting element 310 enters the first adhesive layer 320, the optical properties may change due to the air gap between the first light emitting element 310 and the first adhesive layer 320. When the first adhesive layer 320 includes the refractive index matching layer 324, the refractive index matching layer 324 can fill the air gap between the first light emitting element 310 and the first adhesive layer 320, thereby improving the optical properties between the first light emitting element 310 and the first adhesive layer 320, for example, reducing the light loss caused by light reflection between the first light emitting element 310 and the first adhesive layer 320. In some embodiments, the refractive index matching layer 324 can also serve as a protective layer to protect the antenna 322B of the first metasurface 322. In some embodiments, the refractive index matching layer 324 can be made of organic glue.

[0030] Figure 4 In some other embodiments of the present disclosure, Figure 2 FIG. 1 is an exploded view of the first adhesive layer 320 . Figure 4 The first adhesive layer 320 and Figure 3 The first adhesive layer 320 is similar to the first adhesive layer 320 of Figure 4 The first metasurface 322 further includes a distributed Bragg reflector 326. The distributed Bragg reflector 326 may be below the first metasurface 322, and the distributed Bragg reflector 326 may also be used to allow the first color light emitted by the first light emitting element 310 to pass through and reflect the second color light emitted by the second light emitting element 330. The position of the distributed Bragg reflector 326 is not limited to the following: Figure 4 As shown, for example, a distributed Bragg reflector 326 may also be located on the first metasurface 322. The distributed Bragg reflector 326 may be formed by alternating high refractive index material layers and low refractive index material layers. In some embodiments, a refractive index matching layer 324 may also be coated on the distributed Bragg reflector 326.

[0031] The second adhesive layer 340 includes a second metasurface 342 and a refractive index matching layer 344. The second metasurface 342 allows the first color light emitted by the first light emitting element 310 and the second color light emitted by the second light emitting element 330 to pass through and reflects the third color light emitted by the third light emitting element 350. The width and arrangement period of the antenna of the second metasurface 342 can be designed to be different from those of the first metasurface 322 to achieve the above purpose. Other relevant details of the second metasurface 342 and the refractive index matching layer 344 are as follows: Figure 3 The first metasurface 322 and the refractive index matching layer 324 are the same in detail, so they are not repeated here. In some embodiments, the second adhesive layer 340 may also include a distributed Bragg reflector, and the position of the distributed Bragg reflector of the second adhesive layer 340 may also be as follows: Figure 4 The distributed Bragg reflector of the second adhesive layer 340 can be used to allow the first color light emitted by the first light emitting element 310 and the second color light emitted by the second light emitting element 330 to pass through and reflect the third color light emitted by the third light emitting element 350 .

[0032] The first Metasurface 322 of the first adhesive layer 320 and the second Metasurface 342 of the second adhesive layer 340 can also be used to adjust the direction of light deflection, so that the light has directionality, and can therefore be applied to indoor positioning. The first Metasurface 322 of the first adhesive layer 320 and the second Metasurface 342 of the second adhesive layer 340 can also provide a focusing effect to increase the intensity of light. In addition, the first Metasurface 322 of the first adhesive layer 320 and the second Metasurface 342 of the second adhesive layer 340 can also change the polarization direction of light to expand the application level of visible light communication.

[0033] Figure 5A , Figure 5B and Figure 5C Schematic diagrams of using the first adhesive layer 320 and the second adhesive layer 340 to filter the first color light L1, the second color light L2, and the third color light L3 are respectively shown in some embodiments of the present disclosure. Figure 5A , Figure 5B and Figure 5C In the embodiment, the first adhesive layer 320 is designed to allow the first color light L1 to pass through and reflect the second color light L2. The second adhesive layer 340 is designed to allow the first color light L1 and the second color light L2 to pass through and reflect the third color light L3. Figure 5A In the embodiment, when the first light emitting element 310 emits the first color light L1, the first color light L1 can pass through the first adhesive layer 320 and the second adhesive layer 340 and emit upward. Figure 5B In the embodiment, when the second light emitting element 330 emits the second color light L2, the second color light L2 may pass through the second adhesive layer 340 or be reflected by the first adhesive layer 320 and pass through the second adhesive layer 340 to emit light upward. Figure 5CWhen the third light emitting element 350 emits the third color light L3, the third color light L3 may directly emit upward or be reflected by the second adhesive layer 340 and emit upward. Since the wavelengths of the color lights emitted by the first light emitting element 310, the second light emitting element 330 and the third light emitting element 350 decrease from bottom to top, the first adhesive layer 320 and the second adhesive layer 340 can prevent the short-wavelength color light emitted by the light emitting element of the upper layer from affecting the light emitting element of the lower layer and causing photoluminescence (for example, the short-wavelength color light of the upper layer may enter the quantum dot layer of the light emitting element of the lower layer and cause photoluminescence), thereby avoiding unexpected light emission. In other words, if the wavelengths of the colored light emitted by the first light-emitting element 310, the second light-emitting element 330, and the third light-emitting element 350 increase from bottom to top and the light-emitting element stack 300 is maintained to emit light upward, the short-wavelength colored light emitted by the light-emitting element of the lower layer may affect the light-emitting element of the upper layer and cause photoluminescence (for example, the short-wavelength colored light below may enter the quantum dot layer of the light-emitting element above and cause photoluminescence), resulting in unexpected light emission. Since the first adhesive layer 320 can reflect the second colored light L2 emitted by the second light-emitting element 330, and the second adhesive layer 340 can reflect the third colored light L3 emitted by the third light-emitting element 350, the first adhesive layer 320 and the second adhesive layer 340 can also recycle the back-lighting of the second light-emitting element 330 and the third light-emitting element 350, thereby improving the final light emission intensity. In some embodiments, since a small amount of the third color light L3 may still pass through the second adhesive layer 340 and reach the first adhesive layer 320, the first adhesive layer 320 may also be designed to reflect the third color light L3 emitted by the third light-emitting element 350 to prevent the third color light L3 emitted by the third light-emitting element 350 from affecting the first light-emitting element 310 of the first adhesive layer 320.

[0034] In this way, the first color light L1, the second color light L2 and the third color light L3 can emit light upward and can be mixed into any color light by independently controlling the first light-emitting element 310, the second light-emitting element 330 and the third light-emitting element 350. Specifically, the switch or intensity of the first color light, the second color light and the third color light can be controlled to cause different composition ratios of the first color light, the second color light and the third color light. When the intensities of the first color light, the second color light and the third color light are different, a function similar to amplitude modulation can be achieved to mix any color light. Different colors of light can represent different channels, so the number of channels covering the entire visible light range can be designed. Compared with the original number of channels (three channels represented by the first color light, the second color light and the third color light), the transmission capacity and rate of the multi-channel visible light communication system 100 can be greatly increased.

[0035] In some embodiments, the multi-channel visible light communication system 100 can also be used as a display device, so each light emitting element stack 300 can be used as a pixel unit. The multi-channel visible light communication system 100 can display an image by controlling the individual light emitting element stacks 300 in the multi-channel visible light communication system 100. Since the light emitting elements in each pixel unit are stacked vertically, a display device with a higher resolution can be achieved.

[0036] In summary, some embodiments of the present disclosure provide a multi-channel visible light communication system. The multi-channel visible light communication system includes a stack of light-emitting elements, so that the multi-channel visible light communication system can accommodate more light-emitting elements. The light-emitting elements in each light-emitting element stack can be independently controlled to mix any color light, so that the number of channels in the visible light range covered by any color light increases the transmission capacity and rate. In addition, the light-emitting element stack includes an adhesive layer with a metasurface. The adhesive layer can recycle the back-emitting light of the light-emitting element to increase the light intensity of the multi-channel visible light communication system.

[0037] The above descriptions are only some embodiments of the present disclosure, not all embodiments. Any equivalent changes made to the technical solution of the present disclosure by those skilled in the art after reading the specification of the present disclosure are covered by the claims of the present disclosure.

[0038]

Explanation of symbols

[0039] 100: Multi-channel visible light communication system

[0040] 200: Carrier board

[0041] 300: Light-emitting element stacking

[0042] 310: First light emitting element

[0043] 312, 332, 352: Chip

[0044] 314, 334, 354: Conductive pads

[0045] 320: First adhesive layer

[0046] 322: The first metasurface

[0047] 322A: Substrate

[0048] 322B: Antenna

[0049] 324, 344: Refractive index matching layer

[0050] 326: Distributed Bragg Reflector

[0051] 330: Second light emitting element

[0052] 340: Second adhesive layer

[0053] 342: The Second Metasurface

[0054] 350: The third light emitting element

[0055] L1: First color light

[0056] L2: Second color light

[0057] L3: The third color light.

Claims

1. A multi-channel visible light communication system, characterized in that: Include: Carrier board; A plurality of light emitting element stacks are arranged on the carrier, wherein each of the light emitting element stacks comprises: a first light emitting element; a second light emitting element, on the first light emitting element; The first adhesive layer is between the first light emitting element and the second light emitting element, wherein the first adhesive layer comprises a first metasurface configured to allow the first color light emitted by the first light emitting element to pass through and reflect the second color light emitted by the second light emitting element.

2. The multi-channel visible light communication system according to claim 1, wherein each of the light emitting element stacks further comprises: a third light emitting element, on the second light emitting element; The second adhesive layer is between the second light-emitting element and the third light-emitting element, wherein the second adhesive layer comprises a second metasurface configured to allow the first color light emitted by the first light-emitting element and the second color light emitted by the second light-emitting element to pass through and to reflect the third color light emitted by the third light-emitting element. 3 . The multi-channel visible light communication system according to claim 2 , wherein the first light emitting element, the second light emitting element and the third light emitting element of each of the light emitting element stacks can be controlled independently. 4 . The multi-channel visible light communication system according to claim 2 , wherein the second adhesive layer of each of the light emitting element stacks further comprises a refractive index matching layer covering the second metasurface. 5 . The multi-channel visible light communication system according to claim 2 , wherein the second adhesive layer of each of the light emitting device stacks further comprises a distributed Bragg reflector under the second metasurface.

6. A multi-channel visible light communication system according to claim 2, wherein the wavelength of the first color light emitted by the first light-emitting element is greater than the wavelength of the second color light emitted by the second light-emitting element, and the wavelength of the second color light emitted by the second light-emitting element is greater than the wavelength of the third color light emitted by the third light-emitting element. 7 . The multi-channel visible light communication system according to claim 6 , wherein the first light emitting element is a red light emitting element, the second light emitting element is a green light emitting element, and the third light emitting element is a blue light emitting element. 8 . The multi-channel visible light communication system according to claim 1 , wherein the first adhesive layer of each of the light emitting device stacks further comprises a refractive index matching layer covering the first metasurface. 9 . The multi-channel visible light communication system according to claim 4 , wherein the refractive index matching layer is made of organic glue. 10 . The multi-channel visible light communication system according to claim 1 , wherein the first adhesive layer of each of the light emitting device stacks further comprises a distributed Bragg reflector under the first metasurface.

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