Anti-static interference liquid crystal circuit and liquid crystal module

Abstract

The utility model relates to the technical field of liquid crystal display, in particular to an anti-static interference liquid crystal circuit and a liquid crystal module, the liquid crystal circuit comprises a segment liquid crystal, the segment liquid crystal comprises a plurality of common electrodes and a plurality of segment electrodes, the plurality of common electrodes of the segment liquid crystal are connected with a reference voltage source, and the plurality of segment electrodes of the segment liquid crystal are connected with a control voltage source. A first capacitor and a second capacitor are respectively connected in series between the plurality of section electrodes and the control voltage source and between the plurality of common electrodes and the reference voltage source; a first pull-down resistor and a second pull-down resistor of which one end is grounded are respectively connected between the first capacitor and the section electrodes and between the second capacitor and the common electrodes; the module comprises the liquid crystal circuit, a reference voltage source, a control voltage source and a control unit, wherein the control unit controls the output voltage of the reference voltage source and the control voltage source; the liquid crystal circuit is integrated on the circuit board, the first pull-down resistor and the second pull-down resistor are connected with a grounding layer of the circuit board, and the surface, without pins, of the segment type liquid crystal is covered with a conductive film connected with the grounding layer.

Description

Technical Field

[0001] The embodiments of this specification relate to the field of liquid crystal display technology, and in particular to a liquid crystal circuit and a liquid crystal module that are anti-static interference. Background Art

[0002] Liquid crystal display (LCD) is a technology that uses the physical properties of liquid crystal molecules under the influence of an electric field to display images. It is widely used in electronic devices such as televisions, computer monitors, mobile phones, and tablets. LCD devices mainly include segmented LCDs, dot-matrix LCDs, and character LCDs. Segmented LCDs are primarily used to display numbers and some letters. Their structure is relatively simple and their resolution is relatively low. They are more susceptible to static interference caused by environmental factors and poor wiring, resulting in garbled characters and ghosting, which can affect normal display operation. Existing electrostatic shielding methods often use external shielding structures, such as directly or indirectly grounding an electrostatic shielding shell around the electronic device to conduct away static charges. However, electrostatic shielding shells occupy excess volume, hindering connection and integration with other circuits. Furthermore, they place high demands on the integrity and structure of the shells. If the shells are damaged or structurally altered, they cannot effectively protect the electronic devices within. Utility Model Content

[0003] The embodiments of this specification provide a liquid crystal circuit and a liquid crystal module with anti-static interference, aiming to solve one or more of the above-mentioned problems and other potential problems.

[0004] To achieve the above objectives, the following technical solutions are provided:

[0005] According to a first aspect of the present specification, there is provided a liquid crystal circuit for preventing electrostatic interference, comprising a segmented liquid crystal, wherein the segmented liquid crystal comprises a plurality of common electrodes and a plurality of segment electrodes, the plurality of common electrodes of the segmented liquid crystal being connected to a reference voltage source, the plurality of segment electrodes of the segmented liquid crystal being connected to a control voltage source, a first capacitor being connected in series between the plurality of segment electrodes and the control voltage source, a second capacitor being connected in series between the plurality of common electrodes and the reference voltage source, and a first pull-down resistor and a second pull-down resistor being provided, wherein one end of the first pull-down resistor is connected between the first capacitor and the segment electrode, and the other end is grounded; and one end of the second pull-down resistor is connected between the second capacitor and the common electrode, and the other end is grounded.

[0006] The anti-static interference liquid crystal circuit of the embodiment of this specification directly provides targeted protection for the connection ports of the segmented liquid crystal, reduces the volume occupied by the shielding device, and increases the flexibility of circuit expansion. Specifically, capacitors are set at each common pole and segment electrode of the segmented liquid crystal for electrostatic shielding, so as to avoid affecting the electrostatic shielding effect of all ports connected to it when the same capacitor is damaged, and has a high fault tolerance rate. At the same time, the capacitance requirement of a single capacitor is reduced, and the electrostatic charge absorbed by the capacitor is released in time through the pull-down resistor, further increasing the stability of the liquid crystal circuit.

[0007] In some embodiments, the reference voltage source is ground.

[0008] In some embodiments, a plurality of second capacitors are connected in parallel with the same second pull-down resistor.

[0009] In some embodiments, a magnetic bead is further connected in parallel to the second capacitor.

[0010] In some embodiments, a boost converter and a switching circuit are connected in sequence between the segment electrode and the control voltage source. The boost converter is used to convert the voltage output by the control voltage source. The output voltage of the boost converter is transmitted to the segment electrode through the switching circuit and the first capacitor in sequence.

[0011] In some embodiments, the output end of the boost converter is also connected to a comparison circuit, the output end of the comparison circuit is connected to the enable end of the switching circuit, and the comparison circuit compares the output voltage of the boost converter with the over-low voltage and the over-high voltage respectively. When the output voltage of the boost converter is less than the over-low voltage or greater than the over-high voltage, the comparison circuit sends a shutdown signal to the switching circuit.

[0012] In some embodiments, a feedback circuit is connected between the output terminal of the comparison circuit and the boost converter, and the feedback circuit is used to adjust the voltage division ratio of the boost converter voltage division circuit based on the output of the comparison circuit.

[0013] In some embodiments, the common electrode pin and the segment electrode pin are spaced apart.

[0014] According to the second aspect of the present specification, a liquid crystal module is provided, comprising the above-mentioned anti-static interference liquid crystal circuit, a reference voltage source, a control voltage source and a control unit, wherein the control unit is used to control the output voltage of the reference voltage source and the control voltage source to the segmented liquid crystal; the liquid crystal circuit is integrated on a circuit board, the first pull-down resistor and the second pull-down resistor are connected to the ground layer of the circuit board, and the surface of the segmented liquid crystal without pins is covered with a conductive film, and the edge of the conductive film is connected to the ground layer.

[0015] In some embodiments, an electrostatic shielding layer is provided on a side of the circuit board where the liquid crystal circuit is not provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the embodiments of the present specification will become readily understood by reading the following detailed description with reference to the accompanying drawings, in which several embodiments of the present specification are shown by way of example and not limitation.

[0017] Figure 1 A circuit diagram of a liquid crystal circuit for preventing electrostatic interference according to an embodiment of this specification is shown.

[0018] 1-segment liquid crystal, 21-first capacitor, 22-second capacitor, 31-first pull-down resistor, 32-second pull-down resistor.

[0019] In the various drawings, the same or corresponding reference numerals denote the same or corresponding parts. DETAILED DESCRIPTION

[0020] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to make the present invention more thorough and complete and to fully convey the scope of the present invention to those skilled in the art.

[0021] The term "including" and its variations used in this document indicate open inclusion, that is, "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one other embodiment". Terms such as "upper", "lower", "front", and "rear" indicating placement or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the principles of this specification, and do not indicate or imply that the referred elements must have a specific orientation, be constructed or operate in a specific orientation, and therefore should not be understood as limiting this specification.

[0022] Compared to dot-matrix and character-based LCDs, segmented LCDs offer lower resolution and are typically used in applications with lower display requirements. They primarily display images by controlling the alignment of liquid crystal molecules within the LCD screen through the electric field effect. Specifically, applying a suitable AC voltage to the common and segment electrodes of the segmented LCD creates a voltage difference between the common and segment electrodes, controlling the on / off states of the LCD pixels within the screen and displaying different graphics or characters. Static electricity is a static charge that can accumulate on the surface of electronic devices. When two charged objects come into contact or separate, the charge transfers and discharges, generating electromagnetic interference. Using LCDs in dry environments or in contact with other hardware can easily generate static interference in the LCD circuitry, causing garbled images and ghosting, impacting the display quality. Furthermore, the presence of high-current-carrying conductors around the LCD, generating constant and transient electric fields, can also cause static interference. Currently, anti-static interference in the LCD field is primarily achieved by directing the static charge to the ground, preventing its accumulation and discharge. Compared to other LCDs, segmented LCDs have a simpler internal circuit structure and are therefore more susceptible to static interference.

[0023] An anti-static liquid crystal circuit according to an embodiment of the present specification will be described in detail below with reference to the accompanying drawings. Figure 1A circuit diagram of an anti-static liquid crystal circuit according to an embodiment of the present invention is shown. The anti-static liquid crystal circuit includes a segmented liquid crystal 1, comprising a plurality of common electrodes and a plurality of segment electrodes. The common electrodes of the segmented liquid crystal 1 are connected to a reference voltage source, and the segment electrodes of the segmented liquid crystal 1 are connected to a control voltage source. A first capacitor 21 is connected in series between each of the segment electrodes and the control voltage source, and a second capacitor 22 is connected in series between each of the common electrodes and the reference voltage source. The circuit also includes a first pull-down resistor 31 and a second pull-down resistor 32. The first pull-down resistor 31 has one end connected between the first capacitor 21 and the segment electrodes and the other end connected to ground. The second pull-down resistor 32 has one end connected between the second capacitor 22 and the common electrode and the other end connected to ground. Compared to other liquid crystals, the segmented liquid crystal 1 has fewer pins, so a first capacitor 21 can be connected in series between each segment electrode and the control voltage source, and a second capacitor 22 can be connected in series between each common electrode and the reference voltage source. The first capacitor 21 and the second capacitor 22 can reduce the impact of electrostatic interference on the two pins of the segmented liquid crystal 1 based on their filtering characteristics, especially when the electrostatic interference appears in the form of high-frequency noise, the first capacitor 21 and the second capacitor 22 can effectively attenuate. The first pull-down resistor 31 releases the excess charge accumulated on the first capacitor 21, while limiting the current flow under overvoltage conditions to prevent further interference with the protection circuit. The second pull-down resistor 32 has the same function as the first pull-down resistor 31. All pins of the segmented liquid crystal 1 are respectively provided with capacitors, and the capacitor capacity requirement is low. When a single capacitor is damaged, it is not easy to affect the anti-static interference effect of other pins.

[0024] Specifically, the segmented liquid crystal 1 uses the voltage on the common electrode as a reference voltage. To ensure the stability of the voltage difference between the common electrode and the segment electrode and reduce the difficulty of display control of the segmented liquid crystal 1, the reference voltage is set to 0, that is, the reference voltage source is the ground line. The display of the segmented liquid crystal 1 is controlled by the voltage provided by the control voltage source. At this time, one end of the second capacitor 22 is grounded, and the electrostatic charge absorbed by the second capacitor 22 is directed to the ground line, thereby improving the anti-static interference effect. In addition, multiple second capacitors 22 are connected in parallel with the same second pull-down resistor 32. These multiple second capacitors 22 can discharge through the same resistor, reducing the volume occupied by the liquid crystal circuit on the circuit board. At the same time, the connection of multiple second capacitors 22 to the same pull-down resistor also means that multiple second capacitors 22 are connected in parallel. Even if one of the second capacitors 22 is damaged, the other second capacitors 22 can replace its anti-static interference function, resulting in a higher fault tolerance and stronger anti-interference ability.

[0025] The second capacitor 22 is also connected in parallel with a magnetic bead. A magnetic bead is an electronic component made of ferrite material with high-frequency loss characteristics. It is mainly used to suppress the interference of high-frequency signals. When a high-frequency signal passes through the magnetic bead, eddy current loss is generated inside it, thereby converting the energy of the high-frequency signal into heat energy and consuming it. After the magnetic bead is connected in parallel with the second capacitor 22, it can filter signals in a specific frequency band, that is, it can filter high-frequency electrostatic interference, and this implementation method using magnetic beads is usually more effective than using capacitors or resistors alone.

[0026] Because the reference voltage on the common electrode is 0, it provides better voltage stability relative to the segment electrodes. To further ensure the anti-interference performance of the segment electrode voltage, a boost converter and a switching circuit are sequentially connected between the segment electrodes and the control voltage source. The boost converter is used to convert the voltage output by the control voltage source. The output voltage of the boost converter is then transmitted to the segment electrodes via the switching circuit and the first capacitor 21. The switching circuit controls and selects the appropriate boost converter output voltage based on the voltage requirements of each segment electrode. The boost converter is an electronic device that converts the low voltage input from the control voltage source to the high voltage required by the liquid crystal display. It primarily includes a switching device, an inductor, a capacitor, and a diode. The switching device rapidly switches between on and off states. When the switch is on, the input voltage passes through the inductor, causing it to store energy. When the switch is off, the energy in the inductor is released to the output terminal via a diode or other rectifying element, thereby increasing the voltage. Capacitors and diodes are mainly used for voltage rectification and filtering. Therefore, the boost converter has the functions of filtering, boosting, and voltage stabilization. While providing different voltages for the segmented hydraulic system according to different needs, it also further ensures the anti-interference performance of the signal transmission at one end of the segment electrode.

[0027] In order to avoid damage and interference to the liquid crystal circuit caused by sudden changes in the input voltage of the segment electrode of the segment liquid crystal 1 or voltage mismatch, a comparison circuit is further connected to the output end of the boost converter, and the output end of the comparison circuit is connected to the switching circuit. The comparison circuit compares the output voltage of the boost converter with the over-low voltage and the over-high voltage respectively. When the output voltage of the boost converter is less than the over-low voltage or greater than the over-high voltage, the comparison circuit sends a shutdown signal to the switching circuit to stop supplying power to the segment electrode corresponding to the output voltage of the boost converter. Specifically, the switching circuit may be a switch chip or a MOS transistor. When the switching circuit is a MOS transistor, the source and drain of the MOS transistor are connected to the output of the boost converter and the segment electrode, respectively, and the gate of the MOS transistor is connected to the comparison circuit. The output of the comparison circuit controls the conduction state of the MOS transistor. When the switching circuit is a switch chip, the input of the switch chip is connected to the output of the boost converter, the output of the switch chip is connected to the segment electrode, and the enable terminal of the switch chip is connected to the output of the comparison circuit. When the enable terminal of the switch chip receives a shutdown signal from the comparison circuit, the switch chip stops operating and remains in the off state. The comparison voltage may be a plurality of comparators. The comparators use an undervoltage or overvoltage as a reference voltage to compare the output voltage of the boost converter with the undervoltage or overvoltage, respectively. When the output voltage of the boost converter is less than the undervoltage or greater than the overvoltage, the comparator sends a level signal to the enable terminal of the corresponding switch circuit to stop power supply. The overvoltage and undervoltage can be the maximum and minimum operating voltages of the segmented LCD. For example, the operating voltage range of the BL55070 driver IC for some segmented LCDs is 2.5V to 5.5V. Other voltages can also be specified. A feedback circuit is connected between the output of the comparison circuit and the boost converter. This feedback circuit is configured to adjust the voltage divider ratio of the boost converter's voltage divider circuit based on the output of the comparison circuit to maintain the output voltage of the segmented LCD 1 within a normal range. This not only automatically cuts off the input voltage when a voltage abnormality occurs, but also automatically regulates abnormal voltages to ensure normal operation of the LCD. Specifically, when the comparison circuit outputs an undervoltage signal, meaning that the output voltage of the boost converter is less than the undervoltage, the boost converter's voltage divider ratio is increased using a potentiometer, a resistor divider circuit, or the like.For example, the voltage divider ratio is adjusted using a digital potentiometer connected between the boost converter's input voltage and the switching device, serving as part of the boost converter's voltage divider circuit. When the comparison circuit outputs an overvoltage signal (i.e., when the boost converter's output voltage exceeds the overvoltage), the comparison circuit sends a control signal to the digital potentiometer, changing its resistance to reduce the boost converter's voltage divider ratio. The boost converter's voltage divider ratio is the ratio of the boost converter's output voltage to its input voltage. Furthermore, because the voltage difference between the common electrode pin and the segment electrode pin is significant, the common electrode pin and the segment electrode pin are spaced apart to prevent interference between the pins.

[0028] The present specification also discloses a liquid crystal module comprising the aforementioned anti-static liquid crystal circuit, a reference voltage source, a control voltage source, and a control unit. The control unit is configured to control the voltage output from the reference voltage source and the control voltage source to the segmented liquid crystal 1. The liquid crystal circuit is integrated on a circuit board, with a first pull-down resistor 31 and a second pull-down resistor 32 connected to a ground layer of the circuit board. The surface of the segmented liquid crystal 1 without pins is covered with a conductive film, the edges of which are connected to the ground layer. The conductive film provides a more precise fit with the segmented liquid crystal 1, eliminating the need for excessive circuit space. Furthermore, it can promptly direct static charges on the surface of the segmented liquid crystal 1 into the ground layer. Compared to other shielding devices, the conductive film has a larger contact area with the ground layer, making it less susceptible to individual poor contact areas and providing improved anti-static interference. The ground layer surrounds the circuit board, providing sufficient contact with the conductive film and facilitating connection to components such as the first pull-down resistor 31 and the second pull-down resistor 32 of the segmented liquid crystal 1, thereby reducing wiring complexity and minimizing interference between circuits. An electrostatic shielding layer is further provided on the side of the circuit board where the liquid crystal circuit is not provided, so as to further resist electrostatic interference from the bottom of the liquid crystal circuit.

[0029] Although several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of this specification. Certain features described in the context of separate embodiments may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented in multiple implementations individually or in any suitable subcombination.

[0030] Although the subject matter has been described in language specific to structural features and / or methodological logical acts, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are merely example forms of implementing the claims.

[0031] While the embodiments of the present disclosure have been described above, the above descriptions are illustrative, non-exhaustive, and not intended to be limiting of the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the disclosed embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A liquid crystal circuit for preventing electrostatic interference, comprising a segmented liquid crystal (1), wherein the segmented liquid crystal (1) comprises a plurality of common electrodes and a plurality of segment electrodes, wherein the plurality of common electrodes of the segmented liquid crystal (1) are connected to a reference voltage source, and the plurality of segment electrodes of the segmented liquid crystal (1) are connected to a control voltage source, characterized in that: A first capacitor (21) is connected in series between a plurality of the segment electrodes and the control voltage source, a second capacitor (22) is connected in series between a plurality of the common electrodes and the reference voltage source, and the invention further comprises a first pull-down resistor (31) and a second pull-down resistor (32), wherein one end of the first pull-down resistor (31) is connected between the first capacitor (21) and the segment electrode, and the other end is grounded; and one end of the second pull-down resistor (32) is connected between the second capacitor (22) and the common electrode, and the other end is grounded.

2. The circuit according to claim 1, wherein: The reference voltage source is a ground line.

3. The circuit according to claim 2, characterized in that A plurality of the second capacitors (22) and the same second pull-down resistor (32) are connected in parallel.

4. The circuit according to claim 2, characterized in that The second capacitor (22) is also connected in parallel with a magnetic bead.

5. The circuit according to claim 1, wherein: A boost converter and a switch circuit are connected in sequence between the segment electrode and the control voltage source. The boost converter is used to convert the voltage output by the control voltage source. The output voltage of the boost converter is sequentially transmitted to the segment electrode through the switch circuit and the first capacitor (21).

6. The circuit according to claim 5, characterized in that The output end of the boost converter is also connected to a comparison circuit, and the output end of the comparison circuit is connected to the enable end of the switching circuit. The comparison circuit compares the output voltage of the boost converter with the over-low voltage and the over-high voltage respectively. When the output voltage of the boost converter is less than the over-low voltage or greater than the over-high voltage, the comparison circuit sends a shutdown signal to the switching circuit.

7. The circuit according to claim 6, characterized in that A feedback circuit is connected between the output end of the comparison circuit and the boost converter, and the feedback circuit is used to adjust the voltage division ratio of the boost converter voltage division circuit based on the output of the comparison circuit.

8. The circuit according to claim 1, wherein: The common electrode pin and the segment electrode pin are arranged at intervals.

9. A liquid crystal module, characterized in that: The invention comprises an anti-static interference liquid crystal circuit according to claim 1, a reference voltage source, a control voltage source and a control unit, wherein the control unit is used to control the output voltage of the reference voltage source and the control voltage source to the segmented liquid crystal (1); the liquid crystal circuit is integrated on a circuit board, the first pull-down resistor (31) and the second pull-down resistor (32) are connected to the ground layer of the circuit board, and the surface of the segmented liquid crystal (1) without pins is covered with a conductive film, and the edge of the conductive film is connected to the ground layer.

10. The liquid crystal module according to claim 9, wherein: An electrostatic shielding layer is provided on a side of the circuit board where the liquid crystal circuit is not provided.

Images