Multi-use flexible circuits and related antennas

Abstract

A multi-use connector circuit for use in communications devices is provided. The multi-use connector circuit includes a flexible connector circuit. The first portion of the flexible connector circuit connects a first element of a device to a printed circuit board of the device. The second portion connects a second element of the device, different from the first element, to the printed circuit board.

Description

MULTI-USE FLEXIBLE CIRCUITS AND RELATED ANTENNASCLAIM OF PRIORITY

[0001] This application claims the benefit of and claims priority to U.S. Provisional Application No. 63 / 594,072, filed October 30, 2023, the content of which is hereby incorporated herein by reference in its entirety.FIELD

[0002] The present inventive concept relates generally to antennas and, more particularly, to antennas connected to printed circuit boards using flexible circuits.BACKGROUND

[0003] Antennas are used in smart devices so these devices can communicate with a remote location. Having integrated antennas in the device itself allows the device to have this "smart" capability. However, as devices and their associated housings become smaller and more compact, providing an antenna with good efficiency that can operate in the required bandwidths in the smaller housing becomes a challenge.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Fig. l is a diagram illustrating a conventional liquid crystal display (LCD) coupled to a printed circuit board (PCB) using a flexible circuit.

[0005] Fig. 2 is a diagram illustrating an example flexible circuit.

[0006] Fig. 3 is diagram illustrating a loop antenna sharing a flexible circuit with an LCD in accordance with some embodiments of the present inventive concept.

[0007] Fig. 4 is a diagram illustrating a combination loop antenna and LCD in accordance with some embodiments of the present inventive concept.

[0008] Figs. 5 and 6 are diagrams illustrating a combination loop antenna and LCD in accordance with some embodiments of the present inventive concept.SUMMARY

[0009] Some embodiments of the present inventive concept provide a multi-use connector circuit for use in communications devices. The multi-use connector circuit includes a flexible connector circuit. The first portion of the flexible connector circuit connects a first element of a device to a printed circuit board of the device. The second portion connects a second element of the device, different from the first element, to the printed circuit board.

[0010] In further embodiments of the present inventive concept, the flexible connector circuit may further include a first plurality of traces dedicated to the first element and a second plurality of traces dedicated to the second element. The first and second plurality of traces may be copper traces and the flexible connector circuit may include at least one of polyimide, FR4 and polyester.

[0011] In still further embodiments, the first element may be a liquid crystal display (LCD), and the second element may be an antenna.

[0012] In some embodiments, the second portion of the flexible connector circuit dedicated to an antenna may not be fully connected to the first portion of the flexible connector circuit connected to the LCD and may be behind LCD glass or around the LCD glass.

[0013] In further embodiments, the second portion of the flexible connector circuit dedicated to an antenna may be in a same plane as the first portion of the flexible connector circuit connected to the LCD.

[0014] In still further embodiments, wherein the antenna comprises a near field communication (NFC) loop antenna or any communications antenna.

[0015] In some embodiments, the first and second plurality of traces may be metallic traces bonded to a dielectric layer.

[0016] In further embodiments, the metallic traces may have a thickness from about .0001 inches to .010 inches and the dielectric layer may have a thickness of from about .0005 inches to about .010 inches.

[0017] In still further embodiments, metallic traces may be bonded to the dielectric layer using adhesives or an adhesiveless laminate.

[0018] In some embodiments, the flexible connector circuit may include a single layer flexible circuit or a multi-layer flexible circuit.

[0019] In further embodiments, a number of connections on the flexible connector circuit may be customizable.

[0020] In still further embodiments, the flexible connector circuit may include a third portion to connect a third element of the device, different from the first and second elements, to the printed circuit board.

[0021] Related devices are also provided.DETAILED DESCRIPTION

[0022] The present inventive concept will be described more fully hereinafter with reference to the accompanying figures, in which embodiments of the inventive concept are shown. This inventive concept may, however, be embodied in many alternate forms and should not be construed as limited to the embodiments set forth herein.

[0023] Accordingly, while the inventive concept is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the inventive concept to the particular forms disclosed, but on the contrary, the inventive concept is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the inventive concept as defined by the claims. Like numbers refer to like elements throughout the description of the figures.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the inventive concept. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising," "includes" and / or "including" when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Moreover, when an element is referred to as being "responsive" or "connected" to another element, it can be directly responsive or connected to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly responsive" or "directly connected" to another element, there are nointervening elements present. As used herein the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as

[0025] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this inventive concept belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0026] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the teachings of the disclosure. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

[0027] As discussed in the background, having integrated antennas in the device allows the device to have a "smart" capability. However, as devices become smaller and more compact, providing an antenna with good efficiency at low frequencies in a smaller housing becomes a challenge. Currently, wireless, for example, near field communications (NFC) and liquid crystal display (LCD) functions are separated within various devices. Thus, each element, the NFC antenna and LCD, have separate connections to interface to a main printed circuit board (PCB) in a device. Each connection on the PCB takes up space on the PCB causing the PCB to be larger in size. The larger the PCB, the larger the device must be to accommodate the PCB, thus, making putting these devices in smaller housings more difficult.

[0028] Accordingly, some embodiments of the present inventive concept combine connections needed for an antenna and an LCD using, for example, the same flexible circuit to connect the antenna and the LCD to the PCB. Using a flexible circuit to connect both the antenna and the LCD may reduce the need for duplicative elements in the device and, therefore, reduce the amount of space needed and possibly reduce overall product costs as will be discussed further herein.

[0029] Embodiments of the present inventive concept will be discussed herein with respect to the antenna being an NFC loop antenna, however, it will be understood that embodiments of the present inventive concept are not limited to this configuration. For example, the antenna may be any antenna useful for communication that can be configured as discussed herein. Furthermore, as used herein, a printed circuit board assembly (PCBA) refers to a board that contains all of the necessary electronic components for the board to function as needed, whereas the PCB is just a circuitry board.

[0030] NFC communications generally require a loop antenna that resonates at a specific frequency when presented with a stimulus. A loop antenna is a radio antenna consisting of a “loop” or coil of wire, tubing, or other electrical conductor. In some embodiments of the present inventive concept, the loop antennas use a discrete inductor (approx. $0.20 bill of material (BOM) cost and approx. 60 square (sq.) millimeters (mm) of space on the PCB) or a physical trace route (approx. 280 sq. mm of board space).

[0031] LCDs can be designed into products and positioned over an NFC antenna embedded into a rigid PCB. The presence of the LCD does not substantially inhibit performance of the loop antenna. However, if the LCD uses “chip-on-glass technology,” the typical connection method to the LCD is accomplished using a flexible PCB connection. As used herein, chip-on- glass (abbreviation COG) refers to a display with an integrated display driver. This driver chip is located directly on the glass of the display, therefore "Chip-On-Glass.” The flexible PCB connecting the LCD to the PCB is typically designed in coordination with the chip-on-glass LCD requirements. For example, if the LCD connections needs nine (9) connections (lines), then the flexible PCB is designed to include these nine connections. In other words, the number of connections on the flexible circuit is customizable.

[0032] A conventional LCD 100 including a flexible circuit 110 attached thereto is illustrated in Fig. 1. As illustrated, the LCD 100 is a glass LCD having a flexible circuit 110 attached thereto including a stiffener flex tail 105. The flexible circuit of Fig. 1 includes polyimide; however, embodiments of the present inventive concept are not limited thereto. Other materials that may be used for the flexible circuit 110, without departing from the scope of the present inventive concept, may include, for example, polyimide, FR4, PET (polyester) and the like. FR4 is a standard defined by the National Electrical Manufacturers Association for a glass-reinforced epoxy resin laminate. FR stands for “flame retardant” and indicates that thematerial is compliant with the UL94V-0 standard on plastic material inflammability. The 94V-0 code can be found on all FR-4 PCBs.

[0033] As used herein, a “flexible printed circuit” or “flexible circuit” also known as a flex circuit, consists of a metallic layer of traces, e.g., copper, bonded to a dielectric layer, e.g., polyimide. The thickness of the metal layer may be very thin ( e g. < .0001 inches) to very thick (e.g. > .010 inches) and the dielectric thickness can vary. For example, in some embodiments, the dielectric may have a thickness from .0005 inches to .010 inches. The metal can be bonded to the dielectric using, for example, an adhesive. However, “adhesiveless” laminates that offer great performance and thermal advantages are gaining popularity. Other types of bonding such as vapor deposition can also be used to attach the metal without departing from the scope of the present inventive concept. The flexible printed circuit 110 is by definition “flexible”, i.e. capable of bending without breaking, as shown, for example, in Fig. 2. It will be understood that the flexible printed circuits in accordance with embodiments discussed herein can have varying degrees of flexibility without deviating from the inventive concept.

[0034] Referring again to Fig. 1, a conventional chip-on-glass LCD implementation 100 will be discussed. As illustrated, a flexible PCB 110 is assembled as part of the display. It may be secured with, for example, an adhesive, such as glue, by the LCD manufacturer, and the signals may be exposed near the bottom for connection to the PCB using, for example, an “onboard socket.” Sockets are components used for unplugging and plugging components on PCBs. However, embodiments of the present inventive concept are not limited thereto, flexible circuits may be connected to the PCB in any known manner.

[0035] In an effort to reduce the size of devices as well as possibly reduce cost, embodiments of the present inventive concept provide a multi-use flexible circuit that is used to connect more than one element to the PCB. For example, in some embodiments discussed herein both the LCD and the loop antenna are connected to the PCB using a single flexible circuit. Some embodiments of this combination are illustrated, for example, in Fig. 3. As illustrated in Fig. 3, a loop antenna 320 (NFC loop antenna) is provided on a surface of the LCD (not shown). In the embodiments illustrated in Fig. 3, the traces 330 (e.g. copper traces) of the loop antenna 320 may be provided on a surface of the LCD using a flexible circuit 335. However, the loop antenna does not have to be provided on a flexible circuit. By combining theLCD and loop antenna in the same place, a single flexible circuit 310 having a flex tail 305 can be used to connect both the LCD and the loop antenna 320 to the PCB.

[0036] In particular, as illustrated, the flexible circuit 310 includes an LCD signal section 345 including “N” signal lines 340 and a loop antenna section 336 that includes “M” signal lines. In the example illustrated in Fig. 3, M is equal to two (2) additional signal lines. Thus, the total number of signal lines would be N+2 signal lines 350. However, more or fewer signal lines may be included on the flexible circuit 310 without departing from the scope of the present inventive concept. Furthermore, embodiments are not limited to using the flexible circuit to connect two devices to the board, more devices may be connected to the board using the flexible circuit is some embodiments.

[0037] Thus, in embodiments of the present inventive concept illustrated in Fig. 3, an additional two (2) traces (connections) are provided on the flexible circuit 310 to connect the NFC loop antenna to the PCB. As illustrated in Fig. 3, the portion of the flexible circuit 336 dedicated to the loop antenna 320 is not fully connected to the LCD portion 340 and may be routed, for example, behind the LCD glass (Fig. 4), or around the LCD glass (Fig. 5).

[0038] In particular, Fig. 4 illustrates an LCD 300 having an NFC loop antenna 320 thereon. As discussed above, the loop antenna 320 may be provided on a surface of the LCD using a flexible circuit 310 in some embodiments. The LCD 300 and the NFC loop antenna 320 are coupled to the PCB using a flexible circuit 310. Some portions 345 of the flexible circuit 310 are dedicated to the LCD 300 and some portions 336 of the flexible circuit 310 are dedicated to the loop antenna 320. For example, the portion 345 dedicated to the LCD 300 may be attached (e.g.) glued to the LCD glass as indicated in Fig. 4 and the portion 336 dedicated to the loop antenna may be routed, for example, behind (Fig. 4) or around (Fig. 5), the LCD glass. For example, the NFC loop antenna section 336 may be secured to the back of the LCD glass using, for example, a thin layer of double-sided adhesive. This configuration is provided in Fig. 4 as an example only and it will be understood that embodiments of the present inventive concept are not limited thereto.

[0039] In particular, Figs. 5 and 6 illustrate embodiments of the present inventive concept where the portions 337 and 338 dedicated to the loop antenna may not be routed behind the glass but may be in the same plane as the LCD glass. In Fig. 6, the flexible PCB overlaps the LCD glass. Furthermore, both Figs. 5 and 6 include an NFC tag 390, which is not present in Fig. 4.

[0040] Although embodiments of the present inventive concept are directed to combining the flexible circuit for the LCD and the loop antenna, it will be understood that embodiments of the present inventive concept are not limited thereto. For example, a custom flexible PCB could be expanded to include other functions or components in the design, for example, a light emitting diode (LED). This may require additional signals in the connector. Furthermore, an NFC “tag” integrated circuit could also be included in this flexible PCB area without departing from the scope of the present inventive concept.

[0041] Furthermore, although embodiments of the present inventive concept have been discussed as splitting the single layer flexible circuit, multi-layer flexible circuits may be used without departing from the scope of the present inventive concept. The flexible circuit may be connected to the PCB using any known methods.

[0001] As briefly discussed above, some embodiments of the present inventive concept provide a loop antenna on a surface of an LCD, which allows the flexible circuit connector to be used to connect both the loop antenna and the LCD to the PCB. This may reduce the space needed for these elements in the device as well as lower the total cost of the device itself.

[0002] In the specification, there have been disclosed embodiments of the inventive concept and, although specific terms are used, they are used in a generic and descriptive sense only and not for purposes of limitation. The following claims is provided to ensure that the present application meets all statutory requirements as a priority application in all jurisdictions and shall be construed as setting forth the scope of the present inventive concept.

Claims

WHAT IS CLAIMED IS:

1. A multi-use connector circuit for use in communications devices, the multi-use connector circuit comprising: a flexible connector circuit, wherein a first portion of the flexible connector circuit connects a first element of a device to a printed circuit board of the device; and wherein a second portion connects a second element of the device, different from the first element, to the printed circuit board.

2. The multi-use connector circuit of Claim 1, wherein the flexible connector circuit further comprises a first plurality of traces dedicated to the first element and a second plurality of traces dedicated to the second element.

3. The multi-use connector circuit of Claim 2, wherein the first and second plurality of traces are copper traces and wherein the flexible connector circuit comprises at least one of polyimide, FR4 and polyester.

4. The multi-use connector of Claim 2, wherein the first element is a liquid crystal display (LCD) and the second element is an antenna.

5. The multi-use connector of Claim 4, wherein the second portion of the flexible connector circuit dedicated to an antenna is not fully connected to the first portion of the flexible connector circuit connected to the LCD and is behind LCD glass or around the LCD glass.

6. The multi-use connector of Claim 4, wherein the second portion of the flexible connector circuit dedicated to an antenna is in a same plane as the first portion of the flexible connector circuit connected to the LCD.

7. The multi-use connector of Claim 5, wherein the antenna comprises a near field communication (NFC) loop antenna or any communications antenna.

8. The multi-use connector of Claim 2, wherein the first and second plurality of traces are metallic traces bonded to a dielectric layer.

9. The multi-use connector of Claim 8, wherein metallic traces have a thickness from about .0001 inches to .010 inches and the dielectric layer has a thickness of from about .0005 inches to about .010 inches.

10. The multi-use connector of Claim 9, wherein metallic traces are bonded to the dielectric layer using adhesives or an adhesiveless laminate.

11. The multi-use connector of Claim 1, wherein the flexible connector circuit comprises a single layer flexible circuit or a multi-layer flexible circuit.

12. The multi-use circuit of Claim 1, wherein a number of connections on the flexible connector circuit is customizable.

13. The multi-use circuit of Claim 1, wherein the flexible connector circuit comprises a third portion to connect a third element of the device, different from the first and second elements, to the printed circuit board.

14. A communications device including a liquid crystal display (LCD) and an antenna connection to a printed circuit board of the communications device using a multi-use connector circuit, the multi-use connector circuit comprising: a flexible connector circuit, wherein a first portion of the flexible connector circuit connects the LCD of the device to the printed circuit board of the device; and wherein a second portion connects the antenna of the device to the printed circuit board.

15. The device of Claim 14, wherein the flexible connector circuit further comprises a first plurality of traces dedicated to the LCD and a second plurality of traces dedicated to the antenna.

16. The device of Claim 13, wherein the portion of the flexible connector circuit dedicated to the antenna is not fully connected to the portion of the flexible connector circuit connected to the LCD and is behind LCD glass or around the LCD glass.

17. The device of Claim 13, wherein the portion of the flexible connector circuit dedicated to the antenna is in a same plane as the portion of the flexible connector circuit connected to the LCD.

18. The device of Claim 13, wherein a number of connections on the flexible connector circuit is customizable.

19. The device of Claim 13, wherein the flexible connector circuit comprises a single layer flexible circuit or a multi-layer flexible circuit.

20. The device of Claim 13, wherein the flexible connector circuit comprises a third portion to connect a third element of the device, different from the antenna and the LCD, to the printed circuit board.

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