Short circuit prevention type mobile phone liquid crystal display screen

Abstract

The utility model relates to the technical field of liquid crystal display, and particularly discloses a short circuit prevention type mobile phone liquid crystal display screen, which comprises a liquid crystal screen, a backlight module and a flexible circuit board, the backlight module comprises a flexible circuit board and further comprises a conductive adhesive film, the conductive adhesive film is provided with an adhesion layer and a conductive layer arranged in the adhesion layer, the flexible circuit board is provided with a terminal part and a circuit layer, the terminal part is used for being connected with a mobile phone mainboard, and the circuit layer of the flexible circuit board is attached to the backlight module through the adhesion layer of the conductive adhesive film. The conductive layer of the conductive adhesive film is used for guiding current flow between the flexible circuit board and the backlight module in the direction perpendicular to the plane of the liquid crystal screen. The conductive adhesive film is arranged between the flexible circuit board and the backlight module, current is guided through the conductive layer of the conductive adhesive film, and the short circuit phenomenon between signal transmission contacts or between the signal transmission contacts and other circuits can be effectively avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid crystal display, and in particular discloses a short-circuit-proof mobile phone liquid crystal display screen. Background Art

[0002] In existing mobile phone LCD displays, the complex connection between signal transmission contacts and flexible printed circuit boards often leads to short circuits caused by moisture, static electricity, or overcurrent. Short circuits not only affect display performance but can also cause phone malfunctions and even pose safety risks. Therefore, effectively reducing short circuit risks and enhancing the reliability of LCD displays has become a key research priority in the industry. Utility Model Content

[0003] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide a short-circuit proof mobile phone liquid crystal display screen to solve the above technical problems.

[0004] To achieve the above-mentioned objectives, the utility model provides a short-circuit-proof mobile phone LCD display screen, comprising a liquid crystal screen, a backlight module arranged on the liquid crystal screen, and a flexible circuit board; further comprising a conductive adhesive film, the conductive adhesive film having an adhesive layer and a conductive layer arranged within the adhesive layer, the flexible circuit board having a terminal portion and a circuit layer, the terminal portion being used to connect to the mobile phone motherboard, the circuit layer of the flexible circuit board being attached to the backlight module via the adhesive layer of the conductive adhesive film, and the conductive layer of the conductive adhesive film being used to guide the flow of current between the flexible circuit board and the backlight module in a direction perpendicular to the plane of the liquid crystal screen.

[0005] Furthermore, the thickness of the conductive adhesive film is 15-45 μm.

[0006] Furthermore, a tearable release paper is provided on the adhesive layer of the conductive adhesive layer, and the release paper is used to prevent the adhesive layer from losing its adhesion before the circuit layer of the flexible circuit board is attached to the backlight module.

[0007] Furthermore, the outer cover of the liquid crystal screen is provided with a glass substrate, the glass substrate is provided with a capacitor layer and a signal contact area arranged on the capacitor layer, and the signal contact area is coated with an insulating coating, which is used to prevent short circuits between the contacts of the signal contact area and between the contacts and the capacitor layer.

[0008] Furthermore, the insulating coating includes one or more combinations of polyimide, polytetrafluoroethylene, epoxy resin, silicon oxide, and aluminum oxide.

[0009] Furthermore, the conductive layer includes a plurality of conductive particles, which are uniformly distributed in the adhesive layer. The conductive particles are metal spheres or plastic spheres coated with metal, and the surfaces of the conductive particles are covered with an insulating film.

[0010] Furthermore, the surfaces of the conductive particles are coated with an insulating film by chemical plating or physical vapor deposition (PVD) to improve the distribution stability of the particles in the adhesive layer and reduce the risk of leakage before pressurization.

[0011] Furthermore, the conductive adhesive film is attached between the circuit layer of the flexible circuit board and the backlight module and then pressurized and heated by a hot pressing device to break the insulating film of the conductive particles. The spherical conductive particles are transformed into round cakes after hot pressing to increase the contact area between the flexible circuit board, the backlight module and the conductive particles.

[0012] Furthermore, the particle size of the conductive particles is 2-5 μm, and the metal is one or more combinations of nickel, gold, silver, tin, and copper.

[0013] Furthermore, the conductive particles contain graphene or carbon nanotube materials, which are used to further reduce the vertical resistance and enhance the flexibility of the conductive adhesive film.

[0014] Furthermore, the adhesive layer includes thermosetting resin, thermoplastic resin or UV curing resin.

[0015] Furthermore, the adhesive layer of the conductive adhesive film contains a shape memory polymer, which is used to improve the assembly convenience and fatigue resistance of the conductive adhesive film.

[0016] Furthermore, a short-circuit monitoring module and a circuit protection module are provided between the LCD screen and the flexible circuit board. The short-circuit monitoring module is used to monitor the short-circuit signal between the LCD screen, the flexible circuit board and the backlight module in real time and transmit the signal to the circuit protection module. The circuit protection module is used to disconnect the electrical connection between the LCD screen and the flexible circuit board according to the short-circuit signal.

[0017] Furthermore, the backlight module adopts an insulating material frame, and an electrostatic shielding layer is provided inside the frame. The electrostatic shielding layer is used to reduce the interference of external static electricity on the backlight module.

[0018] Furthermore, the flexible circuit board has a three-layer structure, and the circuit layer is covered by two layers of upper and lower insulating materials.

[0019] The utility model relates to a short-circuit-proof mobile phone liquid crystal display screen, which is intended to solve the display failure and circuit damage caused by unstable current flow or short circuit in traditional liquid crystal display screens. Its main structure includes a liquid crystal screen, a backlight module and a flexible circuit board, and the flexible circuit board is connected to the backlight module through a conductive adhesive film. The adhesive layer of the conductive adhesive film contains a conductive layer, which is used to guide the current to flow in a direction perpendicular to the plane of the liquid crystal screen, thereby avoiding the current directly connecting the circuits in the plane and causing a short circuit. The conductive particles are evenly distributed in the film and coated with an insulating film. The hot pressing treatment can ensure that the contact area of ​​the conductive particles is increased, thereby effectively improving the current conduction performance and reducing leakage.

[0020] The beneficial effects of this utility model are as follows: The short-circuit-proof LCD screen proposed in this utility model effectively prevents short circuits between signal transmission contacts or other circuits by placing a conductive adhesive film between the flexible circuit board and the backlight module, and guiding the current through its conductive layer. This design not only improves the stability of the current, but also increases the contact area between the conductive particles and the circuit through hot pressing technology, further reducing the risk of leakage and short circuits. This greatly enhances the reliability and safety of the LCD screen and solves the short circuit risk problem in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the planar structure of the liquid crystal screen, backlight module, and flexible circuit board of the present invention;

[0022] Figure 2 This is a schematic diagram of the planar structure of the flexible circuit board of the present invention when attached to the backlight module;

[0023] Figure 3 This is a partial cross-sectional structural diagram of the liquid crystal screen and backlight module of the present invention;

[0024] Figure 4 This is a schematic cross-sectional view of the flexible circuit board of the present invention when attached to a backlight module;

[0025] Figure 5 This is a schematic cross-sectional view of the glass substrate of the present invention;

[0026] Figure 6 This is a schematic cross-sectional view of the conductive adhesive film of the present invention;

[0027] Figure 7 This is a schematic cross-sectional structural diagram of the conductive particles of the present invention.

[0028] Reference numerals include:

[0029] 1. LCD screen; 2. Backlight module; 3. Flexible circuit board; 4. Conductive adhesive film; 11. Glass substrate; 12. Capacitor layer; 121. Signal contact area; 122. Insulation coating; 21. LED lamp beads; 31. Terminal part; 32. Circuit layer; 40. Release paper; 41. Adhesive layer; 42. Conductive particles; 421. Insulation film. DETAILED DESCRIPTION

[0030] In order to facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and drawings. The contents mentioned in the embodiments are not intended to limit the present invention.

[0031] See also Figures 1 to 7 As shown, the present invention achieves short-circuit protection by placing a conductive adhesive film 4 between the flexible circuit board 3 and the backlight module 2 of the liquid crystal display. The conductive adhesive film 4 consists of an adhesive layer 41 and a conductive layer embedded therein. The thickness of the conductive adhesive film 4 is controlled to be between 15 and 45 μm, ensuring excellent conductivity and adaptability. The circuit layer 32 of the flexible circuit board 3 is fixed to the backlight module 2 via the adhesive layer 41. At the same time, the conductive particles 42 within the conductive layer guide the flow of current in the vertical direction, thereby preventing short circuits between the horizontal circuits of the flexible circuit board 3 and the backlight module 2.

[0032] Specifically, to prevent the adhesive layer 41 of the conductive film 4 from losing its adhesion during installation, this design incorporates a removable release paper 40 on the film's surface. The terminal portion 31 of the flexible circuit board 3 connects to the phone's motherboard for touchscreen signal transmission, while the circuit layer 32 is secured to the backlight module 2 via the adhesive layer 41. During installation, after the release paper 40 is removed, the adhesive layer 41 adheres tightly to the backlight module 2, ensuring the integrity and adhesion of the film.

[0033] Specifically, the LCD screen 1 is covered by a glass substrate 11, within which a capacitor layer 12 and a signal contact area 121 are located. To prevent short circuits between signal contacts and between a contact and the capacitor layer 12, the signal contact area 121 is coated with an insulating material such as polyimide, polytetrafluoroethylene, or epoxy resin. This insulating coating 122 not only prevents short circuits but also enhances the device's antistatic capabilities, thereby ensuring the display's reliability in complex electromagnetic environments.

[0034] Specifically, LED lamp beads 21 are provided on the top of the backlight module 2 , and the LED lamp beads 21 are evenly distributed throughout the entire liquid crystal screen 1 via the light guide plate of the backlight module 2 .

[0035] Specifically, the conductive layer includes a plurality of conductive particles 42, which are evenly distributed within the adhesive layer 41. The conductive particles 42 are metal spheres or plastic spheres coated with metal, and the surface of the conductive particles 42 is coated with an insulating film 421. The conductive particles 42 are evenly distributed within the adhesive layer 41 of the conductive adhesive film 4, with a particle size of 2-5 μm. The outer layer is coated with an insulating film 421 to prevent the risk of leakage before pressure is applied. During installation, the adhesive film is heated and pressurized by a hot pressing device, destroying the insulating film 421 of the conductive particles 42, causing them to transform from a spherical shape to a disc shape, increasing the contact area with the flexible circuit board 3 and the backlight module 2, thereby significantly improving the conductive efficiency and connection reliability.

[0036] Specifically, the surface of the conductive particles 42 is coated with an insulating film 421 by a physical vapor deposition (PVD) method to improve the distribution stability of the particles in the adhesive layer 41 and reduce the leakage risk P before pressurization. The VD process can generate an ultra-thin and dense insulating film 421 with high purity and strong adhesion, while avoiding the residual contamination problem that may be caused by chemical plating. It is suitable for scenarios with high requirements on coating performance. After coating the insulating film 421, the particles will only be conductive after the insulating film 421 is destroyed by external force (such as hot pressing), thereby ensuring that there is no leakage risk caused by accidental contact of particles during assembly and transportation.

[0037] Specifically, the conductive adhesive film 4 is applied between the circuit layer 32 of the flexible circuit board 3 and the backlight module 2, and then pressurized and heated by a heat press. This ruptures the insulating film 421 of the conductive particles 42. The spherical conductive particles 42 transform into discs after heat pressing, increasing the contact area between the flexible circuit board 3, the backlight module 2, and the conductive particles 42. The thickness of the insulating film 421 is controlled within the range of 10-50 nm, ensuring that it is thin enough to rupture under heat or pressure, restoring conductivity. It also possesses high dielectric strength and stable chemical properties.

[0038] Specifically, the particle size of the conductive particles 42 is 2-5 μm, and the metal is one or more combinations of nickel, gold, silver, tin, and copper. While ensuring the conductive performance of the particles, the 2-5 μm particle size can achieve a high filling rate in the adhesive layer 41, thereby improving the conductivity of the contact area of ​​the circuit board after hot pressing. The smaller particle size can also improve the process adaptability of the conductive adhesive, especially in high-precision assembly scenarios such as mobile phone LCD screens, which can meet the needs of fine-pitch connections. In this embodiment, the conductive particles 42 are gold-plated on the outer layer of the nickel core, which not only reduces costs but also enhances corrosion resistance, providing a more stable solution for flexible screens or folding screens.

[0039] Specifically, the conductive particles 42 contain graphene or carbon nanotubes, which further reduce vertical resistance and enhance the flexibility of the conductive adhesive film 4. Carbon nanotubes are nanoscale tubular materials composed of carbon atoms, exhibiting high longitudinal conductivity and mechanical strength, making them suitable for reinforcing the conductive particles 42. Their unique size and shape enable them to establish low-impedance vertical conductive pathways within and outside the particles. Through composite processing techniques, graphene or carbon nanotubes are coated on the surface of the conductive metal particles, forming a composite particle structure of "metal core + carbon-based conductive layer," ensuring both the high conductivity of metal and the flexibility of carbon-based materials.

[0040] Specifically, the adhesive layer 41 includes a thermosetting resin or a thermoplastic resin or a UV curing resin or a nitrile rubber. The adhesive layer 41 of the conductive adhesive film 4 contains a shape memory polymer, which is used to improve the assembly convenience and fatigue resistance of the conductive adhesive film 4. For thermosetting resins, hot pressing is used to solidify them at a specific temperature and pressure, while enhancing the bonding strength between the particles and the matrix. Thermoplastic resins are formed into thin films by melt extrusion or spraying, and then cooled and formed, which is suitable for large-scale flexible screen production. UV curing resins achieve instant curing through ultraviolet exposure, greatly improving production efficiency, and are suitable for the preparation of precision electronic screens. The combination of these processes and materials enables the adhesive layer 41 to be tightly bonded to the conductive particles 42 and the electrode surface, enhancing mechanical stability while maintaining efficient conductivity.

[0041] Specifically, a short-circuit monitoring module and a circuit protection module are provided between the LCD screen 1 and the flexible circuit board 3. The short-circuit monitoring module is used to monitor the short-circuit signal between the LCD screen 1, the flexible circuit board 3 and the backlight module 2 in real time and transmit the signal to the circuit protection module. The circuit protection module is used to disconnect the electrical connection between the LCD screen 1 and the flexible circuit board 3 according to the short-circuit signal.

[0042] The short-circuit monitoring module includes a current detection unit, a voltage detection unit, and a microprocessor module: The current detection unit consists of a shunt and an amplifier circuit, and is used to detect current changes between the LCD screen 1 and the flexible circuit board 3 in real time. Abnormal current (such as too large or too small) may indicate a short circuit. The voltage detection unit monitors the voltage fluctuations of the LCD screen 1 and the backlight module 2 through a voltage divider circuit and an analog-to-digital converter to determine whether an abnormal short circuit has occurred. The microprocessor module is used to analyze the signals from the current and voltage detection units, determine whether a short circuit has occurred based on a preset threshold, and send the judgment result to the circuit protection module.

[0043] The circuit protection module consists of a relay, a power control switch, and a safety fuse. The relay receives signals from the short-circuit monitoring module and quickly disconnects the LCD 1 from the flexible circuit board 3. The power control switch ensures that the power to the LCD 1 and backlight module 2 is quickly shut off in the event of a short circuit, preventing further expansion of the short-circuit current. The safety fuse provides physical overcurrent protection to prevent further damage if the monitoring or protection system fails.

[0044] Specifically, the backlight module 2 utilizes an insulating material frame with an electrostatic shielding layer disposed within the frame. This shielding layer is used to reduce external static interference with the backlight module 2. The insulating material frame of the backlight module 2 is made of epoxy resin, which has high dielectric strength and impact resistance. An electrostatic shielding layer is embedded within the frame and is composed of metal foil (e.g., aluminum foil or copper foil) or a conductive coating.

[0045] Specifically, the flexible circuit board 3 has a three-layer structure, with the circuit layer 32 encased in two layers of insulating material. Made of highly conductive copper foil, it is responsible for transmitting signals and power between the LCD and the backlight module 2. The upper and lower layers of insulating material are made of highly heat-resistant and bend-resistant materials such as polyimide (PI) or polyester (PET), and serve to encapsulate and isolate the circuit layer 32. At the same time, the insulating layer can effectively reduce signal interference and leakage between the circuit layers 32. This improves the mechanical strength and bending resistance of the flexible circuit board 3, meeting the requirements for thinner and more flexible LCDs.

[0046] Specifically, the outer surface of the flexible circuit board 3 is coated with a black electromagnetic film. This film has strong electromagnetic shielding capabilities, effectively blocking or attenuating the leakage of electromagnetic waves generated by the flexible circuit board 3 during operation, while also preventing external electromagnetic signals from interfering with normal circuit operation. This function is particularly important because mobile phones contain densely packed circuits and high-frequency signals, making them susceptible to electromagnetic interference that can affect performance. Furthermore, the black electromagnetic film prevents transient voltage breakdown in the flexible circuit board 3 when subjected to electrostatic discharge, protecting its internal components and signal transmission security. Part of the black electromagnetic film also has certain thermal conductivity properties, which evenly distributes heat during operation, preventing localized overheating that could lead to performance degradation or component damage.

[0047] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, according to the concept of the present invention, there may be changes in the specific implementation methods and application scope. The content of this specification should not be understood as limiting the present invention.

Claims

1. A short-circuit-proof mobile phone LCD display, characterized by: The invention comprises a liquid crystal screen (1), a backlight module (2) arranged on the liquid crystal screen (1), and a flexible circuit board (3); and further comprises a conductive adhesive film (4), wherein the conductive adhesive film (4) has an adhesive layer (41) and a conductive layer arranged in the adhesive layer (41); the flexible circuit board (3) has a terminal portion (31) and a circuit layer (32); the terminal portion (31) is used to connect to a mobile phone mainboard; the circuit layer (32) of the flexible circuit board (3) is attached to the backlight module (2) via the adhesive layer (41) of the conductive adhesive film (4); and the conductive layer of the conductive adhesive film (4) is used to guide the flow of current between the flexible circuit board (3) and the backlight module (2) in a direction perpendicular to the plane of the liquid crystal screen (1).

2. The short-circuit-proof mobile phone LCD display according to claim 1, characterized in that: The thickness of the conductive adhesive film (4) is 15-45 μm.

3. The short-circuit-proof mobile phone LCD display according to claim 1, characterized in that: A tearable release paper (40) is provided on the adhesive layer (41) of the conductive adhesive film (4), and the release paper (40) is used to prevent the adhesive layer (41) from losing its adhesive force before the circuit layer (32) of the flexible circuit board (3) is attached to the backlight module (2).

4. The short-circuit-proof mobile phone LCD display according to claim 1, characterized in that: The outer cover of the liquid crystal screen (1) is provided with a glass substrate (11), the glass substrate (11) is provided with a capacitor layer (12) and a signal contact area (121) arranged on the capacitor layer (12), the surface of the signal contact area (121) is coated with an insulating coating (122), and the insulating coating (122) is used to prevent short circuits between contacts of the signal contact area (121) and between the contacts and the capacitor layer (12).

5. The short-circuit-proof mobile phone LCD display according to claim 4, characterized in that: The insulating coating (122) comprises one of polyimide, polytetrafluoroethylene, epoxy resin, silicon oxide, and aluminum oxide.

6. The short-circuit-proof mobile phone LCD display according to claim 1, characterized in that: The conductive layer comprises a plurality of conductive particles (42), the plurality of conductive particles (42) being uniformly distributed in the adhesive layer (41), the conductive particles (42) being metal spheres or plastic spheres with metal coated on their surfaces, and the surfaces of the conductive particles (42) being coated with an insulating film (421).

7. The short-circuit-proof mobile phone LCD display according to claim 6, characterized in that: The conductive adhesive film (4) is attached between the circuit layer (32) of the flexible circuit board (3) and the backlight module (2), and then pressurized and heated by a hot pressing device, so that the insulating film (421) of the conductive particles (42) is broken. The spherical conductive particles (42) are transformed into round cakes after hot pressing, thereby increasing the contact area between the flexible circuit board (3), the backlight module (2), and the conductive particles (42).

8. The short-circuit-proof mobile phone LCD display according to claim 6, characterized in that: The particle size of the conductive particles (42) is 2-5 μm, and the metal is one of nickel, gold, silver, tin, and copper.

9. The short-circuit-proof mobile phone LCD display according to claim 1, characterized in that: The adhesive layer (41) includes a thermosetting resin, a thermoplastic resin, or a UV curing resin.

10. The short-circuit proof mobile phone LCD display according to claim 1, characterized in that: A short-circuit monitoring module and a circuit protection module are provided between the liquid crystal screen (1) and the flexible circuit board (3). The short-circuit monitoring module is used to monitor the short-circuit signal between the liquid crystal screen (1), the flexible circuit board (3) and the backlight module (2) in real time and transmit the signal to the circuit protection module. The circuit protection module is used to disconnect the electrical connection between the liquid crystal screen (1) and the flexible circuit board (3) according to the short-circuit signal.

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