WO2022222803A1 - Liquid crystal display screen with improved resistance to electromagnetic interference - Google Patents

Liquid crystal display screen with improved resistance to electromagnetic interference Download PDF

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Publication number
WO2022222803A1
WO2022222803A1 PCT/CN2022/086474 CN2022086474W WO2022222803A1 WO 2022222803 A1 WO2022222803 A1 WO 2022222803A1 CN 2022086474 W CN2022086474 W CN 2022086474W WO 2022222803 A1 WO2022222803 A1 WO 2022222803A1
Authority
WO
WIPO (PCT)
Prior art keywords
display device
liquid crystal
ground
support frame
conductive member
Prior art date
Application number
PCT/CN2022/086474
Other languages
French (fr)
Inventor
Jianzhong Xie
Luo WANG
Yong Che
Original Assignee
Mettler-Toledo (Changzhou) Measurement Technology Ltd.
Mettler-Toledo (Changzhou) Precision Instruments Ltd.
Mettler-Toledo International Trading (Shanghai) Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mettler-Toledo (Changzhou) Measurement Technology Ltd., Mettler-Toledo (Changzhou) Precision Instruments Ltd., Mettler-Toledo International Trading (Shanghai) Co., Ltd. filed Critical Mettler-Toledo (Changzhou) Measurement Technology Ltd.
Publication of WO2022222803A1 publication Critical patent/WO2022222803A1/en

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Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/35—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being liquid crystals
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/133308—Support structures for LCD panels, e.g. frames or bezels
    • G02F1/133334—Electromagnetic shields
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/136—Liquid crystal cells structurally associated with a semi-conducting layer or substrate, e.g. cells forming part of an integrated circuit
    • G02F1/1362—Active matrix addressed cells
    • G02F1/136204—Arrangements to prevent high voltage or static electricity failures
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0007—Casings
    • H05K9/0054—Casings specially adapted for display applications
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/133308—Support structures for LCD panels, e.g. frames or bezels
    • G02F1/133314—Back frames
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
    • G02F2201/50—Protective arrangements

Definitions

  • the present invention relates to the field of display devices, and in particular, to a liquid crystal display, an electronic weighing instrument, and a cash register comprising the same.
  • a commercial high-definition liquid crystal display is a commonly used ultra-thin display screen, and has been widely applied to products of various business scenarios due to its high cost performance and attractive appearance.
  • the commercial high-definition liquid crystal display screen shows poor resistance to electromagnetic interference in electromagnetic compatibility (EMC) performance testing, and engineers need to spend a lot of time in considering how to improve its EMC performance.
  • EMC electromagnetic compatibility
  • the commercial high-definition liquid crystal display screen comprises a touchscreen, a liquid crystal panel, a sheet metal support frame, a liquid crystal display driver board, and a touchscreen driver board.
  • signal grounds of the liquid crystal display driver board and the touchscreen driver board are directly connected to the sheet metal support frame.
  • RS electromagnetic radiated susceptibility
  • a high-frequency eddy current will form on the sheet metal support frame of the display screen. The high-frequency eddy current enters the signal grounds of the touchscreen driver board and the liquid crystal display driver board, which directly affects the normal operation of the display and the touchscreen.
  • a technical problem to be solved by the present invention is that when a commercial high-definition liquid crystal display screen is affected by an external interference, it is prone to a flashing screen, a black screen, etc., and a touchscreen may be falsely responding to a touch, or intermittently unresponsive to a touch, or jumping around randomly, or the like.
  • the present invention provides a liquid crystal display, an electronic weighing instrument comprising same, or a cash register comprising same.
  • a display device comprises a commercial high-definition liquid crystal display screen having a viewing side and a mounting side, and further comprises a sheet metal support frame on the mounting side, a metal-stud support plate provided on the mounting side of the liquid display screen, and at least one ground isolator having a first end and a second end, wherein the ground isolator is mounted between the sheet metal support frame and the metal-stud support plate, wherein the first end of the ground isolator is connected to the sheet metal support frame, and the second end is connected to the metal-stud support plate.
  • the ground isolator comprises a magnetic ring and a ground wire having a first terminal and a second terminal, wherein the ground wire is wound around the magnetic ring, such that the first terminal of the ground wire is connected to the sheet metal support frame, and the second terminal of the ground wire terminal at the other end of the ground wire is connected to the metal- stud support plate.
  • the ground isolator comprises a printed circuit board having a first side and a second side, a first conductive member, a second conductive member, and at least one magnetic member, wherein the first conductive member is mounted at one end of the first side of the printed circuit board, the second conductive member is mounted at the other end of the second side of the printed circuit board, and the magnetic member is mounted on the printed circuit board, wherein the first conductive member is electrically connected to the sheet metal support frame, and the second conductive member is electrically connected to the metal-stud support plate.
  • the first conductive member and the second conductive member are made of conductive foam or other conductive material with similar elastic properties.
  • a bare copper pour is disposed below the first conductive member and the second conductive member.
  • the magnetic member is made of a soft magnetic material.
  • the magnetic member is envisaged as a magnetic bead.
  • a securing member is disposed on the printed circuit board, and is configured to secure the printed circuit board.
  • the display device comprises one or more of the ground isolators, wherein the ground isolator is mounted at a corner of the sheet metal support frame and the metal-stud support plate.
  • the present invention further provides an electronic weighing instrument, characterized in that the electronic weighing instrument comprises the display device as described above.
  • the present invention further provides a cash register, characterized in that the cash register comprises the display device as described above.
  • the liquid crystal display and the electronic weighing instrument or the cash register comprising the same in the present invention can eliminate a high-frequency eddy current, in a RS testing environment, which is induced on the sheet metal support frame provided on the mounting side of the commercial high-definition liquid crystal display screen commonly used in the industry, and block an external ESD interference pulse from entering the liquid crystal display driver board and the touchscreen driver board through a signal wire and the sheet metal support frame.
  • the width of the first pulse of an ESD model is at the level of sub-nanoseconds, and a frequency band presented is above 1000 MHz, while a frequency band presented by a high-frequency eddy current caused by RS interference on the sheet metal support frame is relatively low in frequency.
  • a soft magnetic material such as a magnetic bead or a magnetic ring, which presents relatively high impedance at an ESD pulse frequency band and presents relatively low impedance at an RS interference signal frequency band is used to make a ground isolator satisfying a structural mounting requirement, to achieve the above mentioned anti-interference objective.
  • inserting a plurality of ground isolators between the sheet metal support frame and the metal-stud support plate can eliminate the high- frequency eddy current on the sheet metal support frame provided on the mounting side of the liquid crystal display screen, and alleviate the spatial coupling interference of ESD.
  • Fig. 1 is a schematic structural diagram of a display device according to the present invention
  • Fig. 2 is a schematic diagram of a commercial high-definition liquid crystal display screen, comprising a touchscreen, a liquid crystal panel, sheet metal support frame provided on the mounting side of the liquid crystal display screen for supporting the panel and providing structural strength, a liquid crystal display driver board, a touchscreen driver board, etc., all of which are purchased from a display supplier
  • Fig. 3 is a schematic structural diagram of an embodiment of a ground isolator of a display device according to the present invention
  • Fig. 4 is a schematic structural diagram of another embodiment of a ground isolator of a display device according to the present invention DETAILED DESCRIPTION OF EMBODIMENTS
  • Fig. 1 is a schematic structural diagram of a display device according to the present invention.
  • Fig. 2 is a diagram of an internal structure of a commercial high-definition display screen.
  • Fig. 3 is a schematic structural diagram of an embodiment of a ground isolator of a display device according to the present invention.
  • Fig. 4 is a schematic structural diagram of another embodiment of a ground isolator of a display device according to the present invention.
  • the present invention discloses a display device, which comprises a commercial high-definition liquid crystal display screen 10 with a viewing side and a mounting side, a metal-stud support plate 20 provided on the mounting side of the liquid crystal display screen 10, and a ground isolator 40, as well as a relationship between the three.
  • the commercial high-definition liquid crystal display screen 10 is obtained by purchase, and comprises: a touchscreen and a liquid crystal panel 10-1 , a sheet metal support frame 10-2 for structural reinforcement, a liquid crystal display driver board 10-3 for liquid crystal displaying, and a touchscreen driver board 10-4 for the touchscreen.
  • the metal-stud support plate 20 is configured for the installation and support of the entire display screen, and is directly electrically connected to a chassis ground.
  • the display device of the present invention comprises at least one ground isolator 40 having a first end and a second end, the ground isolator 40 is mounted between the sheet metal support frame 10-2 and the metal-stud support plate 20, such that the first end of the ground isolator 40 is connected to the sheet metal support frame 10-2, and the second end of the ground isolator 40 is connected to the metal-stud support plate 20.
  • the ground isolator 40B may comprise a magnetic ring 40B-1 and a ground wire 40B-2 having a first terminal and a second terminal, wherein the ground wire 40B-2 is wound around the magnetic ring 40B-1 , such the first terminal (40B-3) of the ground wire 40B-2 is connected to the sheet metal support frame 10-1, and the second terminal 40B of the ground wire 40B-2 is connected to the metal-stud support plate 20.
  • the first terminal (40B-3) of the ground wire 40B-2 is connected to the sheet metal support frame 10-1
  • the second terminal 40B of the ground wire 40B-2 is connected to the metal-stud support plate 20.
  • a thin magnetic ring is suitable for the magnetic ring 40B-1.
  • the ground isolator 40A comprises a printed circuit board 40A-1 having a first side and a second side, a first conductive member 40A-4, a second conductive member 40A-5, and at least one magnetic member 40A-2, wherein the first conductive member 40A-4 is mounted at one end of the first side of the printed circuit board 40A-1 , the second conductive member 40A-5 is mounted at the other end of second side of the printed circuit board 40A-1, the magnetic member 40A-2 is mounted on the printed circuit board 40A-1 , the first conductive member 40A-4 is electrically connected to the sheet metal support frame 10-1, and the second conductive member 40A-5 is electrically connected to the metal-stud support plate 20.
  • the first conductive member 40A-4 and the second conductive member 40A-5 are made of a conductive foam.
  • a bare copper pour is disposed below the first conductive member 40A-4 and the second conductive member 40A-5, and are used to be electrically connected to the metal sheet support frame 10-1 and the metal-stud support plate 20, respectively.
  • the magnetic member 40A-2 is made of a soft magnetic material.
  • the magnetic member 40A-2 may be a magnetic bead.
  • the magnetic bead presents relatively low impedance to the frequency band of a high-frequency eddy current, and thereby rapidly guides, to the chassis ground, the high-frequency eddy current generated on the sheet metal support frame 10-1.
  • the magnetic bead presents relative high impedance to the frequency band of an ESD pulse, and thereby blocks an external ESD interference pulse from entering a core driver board.
  • a securing member 40A-3 is disposed on the printed circuit board 40A-1 and is configured to secure the printed circuit board 40A-1.
  • the securing member 40A-3 may be double-sided adhesive tape.
  • the display device comprises one or more ground isolators 40, wherein the ground isolator 40 may be mounted at a corner of the sheet metal support frame 10-1 and the metal-stud support plate 20.
  • the present invention further provides an electronic weighing instrument or a cash register, wherein the electronic weighing instrument or the cash register comprises the display device as described above.
  • the display device of the present invention provides a novel solution and a method concerning ESD and RS anti-interference:
  • a high-frequency eddy current, in an RS testing environment, which is induced on a sheet metal support frame of a commercial high-definition liquid crystal display screen is eliminated.
  • An external ESD interference pulse is blocked from entering the sheet metal support frame of the commercial high-definition liquid crystal display screen and then a liquid crystal display driver board and a touchscreen driver board through a metal-stud support plate.
  • the width of the first pulse of an ESD model is at the level of sub-nanoseconds, and a frequency band presented is above 1000 MHz, while a frequency band presented by a high-frequency eddy current caused by RS interference on the sheet metal support frame is relatively low in frequency.
  • an innovative ground isolator is provided and is inserted between the sheet metal support frame and the metal-stud support plate. Limited by an ultra-thin design of the display screen, the ground isolator should also be designed to be thin. [0041] Inserting a plurality of ground isolators can eliminate the high-frequency eddy current on the support metal sheet, and alleviate spatial coupling interference of ESD.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mathematical Physics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Theoretical Computer Science (AREA)
  • Electromagnetism (AREA)
  • Liquid Crystal (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Abstract

The present invention provides a display device, and an electronic weighing instrument or a cash register comprising the same. The display device comprises a commercial high-definition liquid crystal display screen (10) having a viewing side and a mounting side, and further comprises a sheet metal support frame (10-2) on the mounting side; a metal-stud support plate (20) provided on the mounting side of the liquid crystal display screen (10); and at least one ground isolator (40) having a first terminal and a second terminal; wherein the ground isolator (40) is mounted between the sheet metal support frame (10-2) and the metal-stud support plate (20), and the first terminal (40B-3) of the ground isolator (40) is connected to the sheet metal support frame (10-2), and the second terminal (40B-4) of the ground isolator (40) is connected to the metal-stud support plate (20). According to the present invention, inserting a plurality of ground isolators (40) between the sheet metal support frame (10-2) and the metal-stud support plate (20) can eliminate a high-frequency eddy current induced on the sheet metal support frame, and alleviate spatial coupling interference of electrostatic discharge (ESD).

Description

LIQUID CRYSTAL DISPLAY SCREEN WITH IMPROVED RESISTANCE TO ELECTROMAGNETIC INTERFERENCE
BACKGROUND OF THE INVENTION
Technical Field
[0001] The present invention relates to the field of display devices, and in particular, to a liquid crystal display, an electronic weighing instrument, and a cash register comprising the same.
Background Art
[0002] A commercial high-definition liquid crystal display is a commonly used ultra-thin display screen, and has been widely applied to products of various business scenarios due to its high cost performance and attractive appearance.
[0003] However, the commercial high-definition liquid crystal display screen shows poor resistance to electromagnetic interference in electromagnetic compatibility (EMC) performance testing, and engineers need to spend a lot of time in considering how to improve its EMC performance.
[0004] The commercial high-definition liquid crystal display screen comprises a touchscreen, a liquid crystal panel, a sheet metal support frame, a liquid crystal display driver board, and a touchscreen driver board. In the commercial high-definition liquid crystal display screen, signal grounds of the liquid crystal display driver board and the touchscreen driver board are directly connected to the sheet metal support frame. When the commercial high-definition liquid crystal display screen is in an electromagnetic radiated susceptibility (RS) testing environment of EMC, a high-frequency eddy current will form on the sheet metal support frame of the display screen. The high-frequency eddy current enters the signal grounds of the touchscreen driver board and the liquid crystal display driver board, which directly affects the normal operation of the display and the touchscreen.
[0005] In addition, in electrostatic discharge (ESD) testing, once an ESD interference pulse enters the two driver boards through the sheet metal support frame and a signal wire, a flashing screen, a black screen, etc. may occur in the commercial high-definition liquid crystal display screen, and the touchscreen may be falsely responding to a touch, or intermittently unresponsive to a touch, or jumping around randomly, or the like. [0006] In view of these problems, a novel solution for the commercial high-definition liquid crystal display screen, and a design of a liquid crystal display is disclosed to overcome the foregoing technical problem.
SUMMARY
[0007] A technical problem to be solved by the present invention is that when a commercial high-definition liquid crystal display screen is affected by an external interference, it is prone to a flashing screen, a black screen, etc., and a touchscreen may be falsely responding to a touch, or intermittently unresponsive to a touch, or jumping around randomly, or the like. To overcome this problem, the present invention provides a liquid crystal display, an electronic weighing instrument comprising same, or a cash register comprising same.
[0008] The present invention solves the above technical problem through the following technical solution: A display device is provided, characterized in that the display device comprises a commercial high-definition liquid crystal display screen having a viewing side and a mounting side, and further comprises a sheet metal support frame on the mounting side, a metal-stud support plate provided on the mounting side of the liquid display screen, and at least one ground isolator having a first end and a second end, wherein the ground isolator is mounted between the sheet metal support frame and the metal-stud support plate, wherein the first end of the ground isolator is connected to the sheet metal support frame, and the second end is connected to the metal-stud support plate.
[0009] According to an embodiment of the present invention, the ground isolator comprises a magnetic ring and a ground wire having a first terminal and a second terminal, wherein the ground wire is wound around the magnetic ring, such that the first terminal of the ground wire is connected to the sheet metal support frame, and the second terminal of the ground wire terminal at the other end of the ground wire is connected to the metal- stud support plate.
[0010] According to an embodiment of the present invention, the ground isolator comprises a printed circuit board having a first side and a second side, a first conductive member, a second conductive member, and at least one magnetic member, wherein the first conductive member is mounted at one end of the first side of the printed circuit board, the second conductive member is mounted at the other end of the second side of the printed circuit board, and the magnetic member is mounted on the printed circuit board, wherein the first conductive member is electrically connected to the sheet metal support frame, and the second conductive member is electrically connected to the metal-stud support plate.
[0011] According to an embodiment of the present invention, the first conductive member and the second conductive member are made of conductive foam or other conductive material with similar elastic properties.
[0012] According to an embodiment of the present invention, a bare copper pour is disposed below the first conductive member and the second conductive member.
[0013] According to an embodiment of the present invention, the magnetic member is made of a soft magnetic material.
[0014] According to an embodiment of the present invention, the magnetic member is envisaged as a magnetic bead.
[0015] According to an embodiment of the present invention, a securing member is disposed on the printed circuit board, and is configured to secure the printed circuit board.
[0016] According to an embodiment of the present invention, the display device comprises one or more of the ground isolators, wherein the ground isolator is mounted at a corner of the sheet metal support frame and the metal-stud support plate.
[0017] The present invention further provides an electronic weighing instrument, characterized in that the electronic weighing instrument comprises the display device as described above.
[0018] The present invention further provides a cash register, characterized in that the cash register comprises the display device as described above.
[0019] The positive effects of the present invention are as follows, the liquid crystal display and the electronic weighing instrument or the cash register comprising the same in the present invention can eliminate a high-frequency eddy current, in a RS testing environment, which is induced on the sheet metal support frame provided on the mounting side of the commercial high-definition liquid crystal display screen commonly used in the industry, and block an external ESD interference pulse from entering the liquid crystal display driver board and the touchscreen driver board through a signal wire and the sheet metal support frame. The principle is as follows, the width of the first pulse of an ESD model is at the level of sub-nanoseconds, and a frequency band presented is above 1000 MHz, while a frequency band presented by a high-frequency eddy current caused by RS interference on the sheet metal support frame is relatively low in frequency. A soft magnetic material such as a magnetic bead or a magnetic ring, which presents relatively high impedance at an ESD pulse frequency band and presents relatively low impedance at an RS interference signal frequency band is used to make a ground isolator satisfying a structural mounting requirement, to achieve the above mentioned anti-interference objective.
[0020] According to the display device, inserting a plurality of ground isolators between the sheet metal support frame and the metal-stud support plate can eliminate the high- frequency eddy current on the sheet metal support frame provided on the mounting side of the liquid crystal display screen, and alleviate the spatial coupling interference of ESD.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above features, properties and advantages of the present invention will become clearer based on the description below in conjunction with the accompanying drawings and embodiments, and the same features are denoted by the same reference numerals throughout the figures, in which:
Fig. 1 is a schematic structural diagram of a display device according to the present invention
Fig. 2 is a schematic diagram of a commercial high-definition liquid crystal display screen, comprising a touchscreen, a liquid crystal panel, sheet metal support frame provided on the mounting side of the liquid crystal display screen for supporting the panel and providing structural strength, a liquid crystal display driver board, a touchscreen driver board, etc., all of which are purchased from a display supplier
Fig. 3 is a schematic structural diagram of an embodiment of a ground isolator of a display device according to the present invention
Fig. 4 is a schematic structural diagram of another embodiment of a ground isolator of a display device according to the present invention DETAILED DESCRIPTION OF EMBODIMENTS
[0022] To make the above objects, features and advantages of the present invention more apparent and easier to understand, specific implementations of the present invention are described in detail below with reference to the accompanying drawings.
[0023] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The same reference numerals used in all the accompanying drawings denote identical or similar parts wherever possible.
[0024] Furthermore, although the terms used in the present invention are selected from well- known common terms, some of the terms mentioned in the description of the present invention may have been selected by the applicant according to his or her determination, and the detailed meaning thereof is described in the relevant section described herein.
[0025] Furthermore, the present invention must be understood, not simply by the actual terms used but also by the meanings encompassed by each term.
[0026] Fig. 1 is a schematic structural diagram of a display device according to the present invention. Fig. 2 is a diagram of an internal structure of a commercial high-definition display screen. Fig. 3 is a schematic structural diagram of an embodiment of a ground isolator of a display device according to the present invention. Fig. 4 is a schematic structural diagram of another embodiment of a ground isolator of a display device according to the present invention.
[0027] As shown is Fig. 1, Fig. 3, and Fig. 4, the present invention discloses a display device, which comprises a commercial high-definition liquid crystal display screen 10 with a viewing side and a mounting side, a metal-stud support plate 20 provided on the mounting side of the liquid crystal display screen 10, and a ground isolator 40, as well as a relationship between the three. The commercial high-definition liquid crystal display screen 10 is obtained by purchase, and comprises: a touchscreen and a liquid crystal panel 10-1 , a sheet metal support frame 10-2 for structural reinforcement, a liquid crystal display driver board 10-3 for liquid crystal displaying, and a touchscreen driver board 10-4 for the touchscreen. The metal-stud support plate 20 is configured for the installation and support of the entire display screen, and is directly electrically connected to a chassis ground.
[0028] The display device of the present invention comprises at least one ground isolator 40 having a first end and a second end, the ground isolator 40 is mounted between the sheet metal support frame 10-2 and the metal-stud support plate 20, such that the first end of the ground isolator 40 is connected to the sheet metal support frame 10-2, and the second end of the ground isolator 40 is connected to the metal-stud support plate 20.
[0029] As an example, as shown in Fig. 3, the ground isolator 40B may comprise a magnetic ring 40B-1 and a ground wire 40B-2 having a first terminal and a second terminal, wherein the ground wire 40B-2 is wound around the magnetic ring 40B-1 , such the first terminal (40B-3) of the ground wire 40B-2 is connected to the sheet metal support frame 10-1, and the second terminal 40B of the ground wire 40B-2 is connected to the metal-stud support plate 20. For the design of an ultra-thin display, only a thin magnetic ring is suitable for the magnetic ring 40B-1.
[0030] Preferably, as shown in Fig. 4, the ground isolator 40A comprises a printed circuit board 40A-1 having a first side and a second side, a first conductive member 40A-4, a second conductive member 40A-5, and at least one magnetic member 40A-2, wherein the first conductive member 40A-4 is mounted at one end of the first side of the printed circuit board 40A-1 , the second conductive member 40A-5 is mounted at the other end of second side of the printed circuit board 40A-1, the magnetic member 40A-2 is mounted on the printed circuit board 40A-1 , the first conductive member 40A-4 is electrically connected to the sheet metal support frame 10-1, and the second conductive member 40A-5 is electrically connected to the metal-stud support plate 20.
[0031] Preferably, the first conductive member 40A-4 and the second conductive member 40A-5 are made of a conductive foam. A bare copper pour is disposed below the first conductive member 40A-4 and the second conductive member 40A-5, and are used to be electrically connected to the metal sheet support frame 10-1 and the metal-stud support plate 20, respectively.
[0032] Preferably, the magnetic member 40A-2 is made of a soft magnetic material. For example, the magnetic member 40A-2 may be a magnetic bead. According to the display device, the magnetic bead presents relatively low impedance to the frequency band of a high-frequency eddy current, and thereby rapidly guides, to the chassis ground, the high-frequency eddy current generated on the sheet metal support frame 10-1. In addition, according to the display device, the magnetic bead presents relative high impedance to the frequency band of an ESD pulse, and thereby blocks an external ESD interference pulse from entering a core driver board.
[0033] In addition, a securing member 40A-3 is disposed on the printed circuit board 40A-1 and is configured to secure the printed circuit board 40A-1. For example, the securing member 40A-3 may be double-sided adhesive tape.
[0034] According to the foregoing structural description, the display device comprises one or more ground isolators 40, wherein the ground isolator 40 may be mounted at a corner of the sheet metal support frame 10-1 and the metal-stud support plate 20.
[0035] The present invention further provides an electronic weighing instrument or a cash register, wherein the electronic weighing instrument or the cash register comprises the display device as described above.
[0036] In conclusion, for the characteristics of ESD and RS protection of the commercial high- definition liquid crystal display screen, the display device of the present invention provides a novel solution and a method concerning ESD and RS anti-interference:
[0037] A high-frequency eddy current, in an RS testing environment, which is induced on a sheet metal support frame of a commercial high-definition liquid crystal display screen is eliminated.
[0038] An external ESD interference pulse is blocked from entering the sheet metal support frame of the commercial high-definition liquid crystal display screen and then a liquid crystal display driver board and a touchscreen driver board through a metal-stud support plate.
[0039] The width of the first pulse of an ESD model is at the level of sub-nanoseconds, and a frequency band presented is above 1000 MHz, while a frequency band presented by a high-frequency eddy current caused by RS interference on the sheet metal support frame is relatively low in frequency.
[0040] Based on a characteristic that a magnetic bead or a magnetic ring which are made of a soft magnetic material presents different impedance at different frequencies, an innovative ground isolator is provided and is inserted between the sheet metal support frame and the metal-stud support plate. Limited by an ultra-thin design of the display screen, the ground isolator should also be designed to be thin. [0041] Inserting a plurality of ground isolators can eliminate the high-frequency eddy current on the support metal sheet, and alleviate spatial coupling interference of ESD.
[0042] Although specific implementations of the present invention have been described above, those skilled in the art should understand that these are merely examples, and the scope of protection of the present invention is defined by the appended claims. Various alterations or modifications to these implementations can be made by those skilled in the art without departing from the principle and essence of the present invention. However, these alterations and modifications all fall within the scope of protection of the present invention.

Claims

Reference signs list [0043] 10 Commercial high-definition liquid crystal display screen20 Metal-stud support plate 30 Display wiring harness and touchscreen wiring harness40 Ground isolator 10-1 Touchscreen and liquid crystal panel 10-2 Sheet metal support frame 10-3 Liquid crystal display driver board 10-4 T ouchscreen driver board 40A-1 Printed circuit board 40A-2 Magnetic bead 40A-3 Securing member 40A-4 First conductive member 40A-5 Second conductive member 40B-1 Magnetic ring 40B-2 Ground wire 40B-3 First terminal 40B-4 Second terminal Claims
1. A display device comprising: a commercial high-definition liquid crystal display screen (10), having a viewing side and a mounting side; a metal-stud support plate (20), provided on the mounting side of the liquid crystal display screen (10); and at least one ground isolator (40) having a first end and a second end; characterized in that the liquid crystal display screen (10) further comprises a sheet metal support frame (10-2) on the mounting side, wherein the ground isolator is mounted between the sheet metal support frame (10-2) and the metal-stud support plate (20), wherein the first end of the ground isolator (40) is connected to the sheet metal support frame (10-2) and the second end is connected to the metal-stud support plate (20).
2. The display device of claim 1 , characterized in that the ground isolator (40B) comprises a magnetic ring (40B-1), and a ground wire (40B-2) having a first terminal (40B-3) and a second terminal (40B-4), wherein the ground wire (40B-2) is wound around the magnetic ring (40B-1), such that the first terminal (40B-3) of the ground wire (40B-2) is connected to the sheet metal support frame (10-2), and the second terminal (40B-4) of the ground wire (40B-2) is connected to the metal-stud support plate (20).
3. The display device of claim 1, characterized in that the ground isolator (40A) further comprises a printed circuit board (40A-1) having a first side and a second side, a first conductive member (40A-4), a second conductive member (40A-5), and at least one magnetic member (40A-2), wherein the first conductive member (40A-4) is mounted at one end of the first side of the printed circuit board (40A-1), the second conductive member (40A-5) is mounted at the other end of the second side of the printed circuit board (40A-1), and the magnetic member (40A-2) is mounted on the printed circuit board (40A-1), wherein the first conductive member (40A-4) is electrically connected to the sheet metal support frame (10-2), and the second conductive member (40A-5) is electrically connected to the metal-stud support plate (20).
4. The display device of claim 3, characterized in that the first conductive member (40-4) and the second conductive member (40A-5) are made of conductive foam or other conductive material with similar elastic properties.
5. The display device of claim 4, characterized in that a bare copper pour is disposed below the first conductive member (40A-4) and the second conductive member (40A-5).
6. The display device of claim 3, characterized in that the magnetic member (40A-2) is made of a soft magnetic material.
7. The display device of claim 6, characterized in that the magnetic member (40A-2) is envisaged as a magnetic bead.
8. The display device of claim 1 , characterized in that a securing member (40A-3) is disposed on the printed circuit board (40A-1) and is configured to facilitate the securing of the printed circuit board (40A-1).
9. The display device of claim 1 , characterized in that the display device comprises a plurality of the ground isolators (40), wherein the ground isolator (40) is mounted at a corner of the sheet metal support frame (10A-2) and the metal-stud support plate (20).
10. An electronic weighing instrument, characterized in that the electronic weighing instrument comprises the display device of any of the preceding claims 1 to 9.
11. A cash register, characterized in that the cash register comprises the display device of any of the preceding claims 1 to 9.
PCT/CN2022/086474 2021-04-19 2022-04-13 Liquid crystal display screen with improved resistance to electromagnetic interference WO2022222803A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202110420445.5A CN115223462A (en) 2021-04-19 2021-04-19 Liquid crystal display, electronic weighing instrument comprising same and cash register product
CN202110420445.5 2021-04-19

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090002594A1 (en) * 2007-06-29 2009-01-01 Sanyo Electric Co., Ltd. Image display device
CN204272588U (en) * 2014-12-25 2015-04-15 北京维信诺光电技术有限公司 A kind of display module with electromagnetic isolation structure
KR101764146B1 (en) * 2017-05-26 2017-08-02 이은숙 Electromagnetic compatibility module of combined line filter using multi-layer board
CN206684240U (en) * 2017-03-21 2017-11-28 一汽-大众汽车有限公司 A kind of ground isolating device and emc testing system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090002594A1 (en) * 2007-06-29 2009-01-01 Sanyo Electric Co., Ltd. Image display device
CN204272588U (en) * 2014-12-25 2015-04-15 北京维信诺光电技术有限公司 A kind of display module with electromagnetic isolation structure
CN206684240U (en) * 2017-03-21 2017-11-28 一汽-大众汽车有限公司 A kind of ground isolating device and emc testing system
KR101764146B1 (en) * 2017-05-26 2017-08-02 이은숙 Electromagnetic compatibility module of combined line filter using multi-layer board

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