A single pulse erasable liquid crystal handwriting tablet with adjustable voltage and adjustable pulse width

Abstract

The present invention discloses a single-pulse erasable liquid crystal handwriting tablet with adjustable voltage and adjustable pulse width, which is composed of the following technologies: integrated positive and negative single pulse alternating output technology and pulse width adjustable technology, wherein the integrated positive and negative single pulse alternating output technology comprises: U1 is an integrated circuit with built-in boosting and key recognition, powered by a 3V button battery, and a peripheral inductor L1 and a diode D1 form a boosting circuit; when keys are operated, positive and negative single pulse signals alternately appear at the output end according to the order in which the keys are operated; the present invention aims at the requirement that the erasing voltage value and pulse width need to be adjusted when liquid crystal diaphragms from different manufacturers are used in liquid crystal handwriting tablets, realizes a convenient and fast adaptation method, shortens the R&D development time and the production introduction time, optimizes the supply chain control, and saves the enterprise management cost.

Description

Technical Field

[0001] The invention belongs to the technical field related to electronic information and terminal technology, and in particular relates to a single-pulse erasing liquid crystal handwriting board with adjustable voltage and adjustable pulse width. Background Art

[0002] LCD tablets are widely used in teaching and office fields. They are environmentally friendly and eye-protecting, and are very popular among users. Existing LCD tablets use the reflection of light at the indentation to achieve what you write (draw) and what you see, and can be erased with one click.

[0003] One-touch erasing is achieved by applying a pulse voltage of a certain voltage value and pulse width at the two poles of the liquid crystal diaphragm, which is relatively easy to implement and mass produce. At present, most liquid crystal handwriting tablets use two pulses of sufficient pulse width and voltage to achieve erasing. To ensure the consistency of the cleanliness of batch operations, the pulse width and voltage of general handwriting tablet products are set much higher than the actual film erasing requirements, which will cause flickering during film erasing and the erasing time to be too long. After erasing, writing cannot be done within 2 to 3 seconds, and the user experience is poor. Long-term ultra-high pressure on the liquid crystal diaphragm will also cause local breakdown of the diaphragm to form bad pixels.

[0004] When multiple suppliers of liquid crystal films are supplying at the same time, the driver board design often needs to be changed according to the different parameters of the liquid crystal films of different manufacturers, which causes great trouble to the entire production management. Summary of the invention

[0005] The purpose of the present invention is to provide a single-pulse erasable liquid crystal writing board with adjustable voltage and adjustable pulse width, so as to solve the problem mentioned in the above background technology that when multiple liquid crystal film suppliers supply at the same time, it is often necessary to change the design of the driving board according to the different parameters of the liquid crystal films of different manufacturers, which causes great trouble to the entire production management.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A single pulse erasable liquid crystal handwriting board with adjustable voltage and adjustable pulse width, which is composed of the following technologies: integrated positive and negative single pulse alternating output technology and pulse width adjustable technology,

[0008] The integrated positive and negative single pulse alternating output technology includes: U1 is an integrated circuit with built-in boost and key recognition, powered by a 3V button battery, and the peripheral inductor L1 and the diode D1 form a boost circuit; when the key is operated, the output end will alternately display positive and negative single pulse signals according to the order of the key operation;

[0009] The pulse width adjustable technology includes: R1 of the VSET pin is used to set the amplitude V of the pulse voltage, and the calculation formula is as follows: V = (R1 + 40K) / 10K, 40K and 10K are fixed values, and the fixed value values ​​are based on the voltage offset and amplification factor inside the chip. The required voltage amplitude V can be obtained by adjusting the value of R1. The adjustable resistor can be used to debug the optimal value in the research and development test stage;

[0010] The pulse width adjustable technology includes: R2 of the TSET pin is used to set the pulse width T, and the calculation formula is as follows: T = R2 / 10K + 22ms, 10K and 22ms are fixed values, and the fixed value values ​​are determined by the setting amplification loop parameters and pulse trigger bias time parameters inside the chip. The required pulse width T can be obtained by adjusting the value of R2. The adjustable resistor can be used to debug the optimal value in the research and development test stage;

[0011] The combination of the integrated positive and negative single pulse alternating output technology and the pulse width adjustable technology is a single pulse erasing liquid crystal handwriting board with adjustable voltage and adjustable pulse width.

[0012] Compared with the prior art, the present invention provides a single pulse erasing liquid crystal handwriting tablet with adjustable voltage and adjustable pulse width, which has the following beneficial effects:

[0013] The present invention aims at the requirement that the erasing voltage value and the pulse width need to be adjusted when using liquid crystal films from different manufacturers on liquid crystal writing tablets, thereby realizing a convenient and fast adaptation method, shortening the R&D development time and the production introduction time, optimizing the supply chain control, and saving the enterprise management costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0015] Figure 1 This is the integrated positive and negative single pulse alternating output technology circuit diagram proposed by the present invention;

[0016] Figure 2 This is a circuit diagram of the pulse voltage amplitude adjustable technology proposed by the present invention;

[0017] Figure 3 The circuit diagram of the pulse width adjustable technology proposed by the present invention; DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The present invention provides a technical solution:

[0020] A single pulse erasable liquid crystal handwriting board with adjustable voltage and adjustable pulse width, which is composed of the following technologies: integrated positive and negative single pulse alternating output technology and pulse width adjustable technology,

[0021] The integrated positive and negative single pulse alternating output technology includes: U1 is an integrated circuit with built-in boost and key recognition, powered by a 3V button battery, and the external inductor L1 and diode D1 form a boost circuit; when the key is operated, the output end will alternately display positive and negative single pulse signals according to the order of the key operation, such as Figure 1 As shown: the first key press triggers a positive pulse, and the second key press triggers a negative pulse. The single pulse clearing LCD tablet technology can be more efficient than the double pulse execution and has a shorter clearing time. In addition, the positive and negative pulse outputs are used alternately, which will not cause the liquid crystal to flip in the same direction all the time, and will not cause continuous pressure in the same direction to damage the liquid crystal molecules.

[0022] Pulse voltage amplitude adjustable technology includes: Figure 2 R1 connected to the VSET pin is used to set the amplitude V of the pulse voltage. The calculation formula is as follows: V = (R1 + 40K) / 10K. 40K and 10K are fixed values. The fixed values ​​are based on the voltage offset and amplification factor inside the chip. By adjusting the value of R1, the required voltage amplitude V can be obtained. In the R&D and testing phase, the adjustable resistor can be used to debug the optimal value.

[0023] Pulse width adjustable technology includes: Figure 3 R2 connected to the TSET pin is used to set the pulse width T. The calculation formula is as follows: T = R2 / 10K + 22ms. 10K and 22ms are fixed values. The fixed values ​​are determined by the chip's internal amplifier circuit parameters and pulse trigger bias time parameters. By adjusting the value of R2, the required pulse width T can be obtained. The adjustable resistor can be used to debug the optimal value during the R&D and testing phase.

[0024] The integrated positive and negative single pulse alternating output technology and the pulse width adjustable technology are combined to form a single pulse erasing liquid crystal handwriting board with adjustable voltage and adjustable pulse width.

[0025] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A single pulse erasable liquid crystal handwriting tablet with adjustable voltage and adjustable pulse width, which is composed of the following technologies: integrated positive and negative single pulse alternating output technology and pulse width adjustable technology, characterized in that: The integrated positive and negative single pulse alternating output technology includes: U1 is an integrated circuit with built-in boost and key recognition, powered by a 3V button battery, and the peripheral inductor L1 and the diode D1 form a boost circuit; when the key is operated, the output end will alternately display positive and negative single pulse signals according to the order of the key operation; The integrated positive and negative single pulse alternating output technology includes: R1 of the VSET pin is used to set the amplitude V of the pulse voltage, and the calculation formula is as follows: V = (R1 + 40K) / 10K, 40K and 10K are fixed values, and the fixed value values ​​are based on the voltage offset and amplification factor inside the chip. The required voltage amplitude V can be obtained by adjusting the value of R1. The optimal value is debugged using an adjustable resistor during the R&D test phase; The pulse width adjustable technology includes: R2 of the TSET pin is used to set the pulse width T, and the calculation formula is as follows: T=R2 / 10K+22ms, 10K and 22ms are fixed values, and the fixed values ​​are determined according to the setting amplification loop parameters and pulse trigger bias time parameters inside the chip. The required pulse width T can be obtained by adjusting the value of R2. The adjustable resistor is used to debug the optimal value during the research and development test stage.

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