CN107316597B

CN107316597B - Open circuit and short circuit detection system of liquid crystal display module

Info

Publication number: CN107316597B
Application number: CN201710687233.7A
Authority: CN
Inventors: 李继龙; 骆志锋
Original assignee: Shenzhen Tongxingda Technology Co Ltd
Current assignee: Shenzhen Tongxingda Technology Co Ltd
Priority date: 2017-08-11
Filing date: 2017-08-11
Publication date: 2020-11-13
Anticipated expiration: 2037-08-11
Also published as: CN107316597A

Abstract

The invention discloses a liquid crystal display module open circuit short circuit detection system, which comprises: MCU, with MCU electric connection's register, with MCU electric connection's current detection circuit, with current detection circuit electric connection's auxiliary circuit and with MCU electric connection's audible and visual alarm device, current detection circuit is used for detecting the size of the electric current that flows through auxiliary circuit, MCU is right the register sends sense signal and clock signal, handles and starts audible and visual alarm device to current detection circuit's data. The automatic detection liquid crystal display module replaces the original manual detection method, greatly improves the detection efficiency, has low detection misjudgment rate and is more reliable than manual detection, and reduces the reject ratio of products.

Description

Open circuit and short circuit detection system of liquid crystal display module

Technical Field

The invention relates to the field of liquid crystal display modules, in particular to a liquid crystal display module open-circuit short-circuit detection system.

Background

The liquid crystal display module is simply a screen and a backlight, and the principle of liquid crystal display is that a backlight component emits uniform surface light, the light is transmitted to eyes of people through a liquid crystal screen, and the screen is used for processing the light according to pixels so as to display images. The mobile phone has the characteristics of thin body, space saving, power saving, low radiation, soft picture, no harm to eyes and the like, and the liquid crystal display module plays an important role in each component of the mobile phone. The liquid crystal display module is provided with a plurality of pins, and whether the pins are open or short-circuited needs to be detected during production and processing, so that damage to a product caused by electrification under the condition of short circuit of the product is avoided, and meanwhile, defective products of the type can be intercepted. At present, the method for detecting the open circuit or the short circuit of the liquid crystal display module is to observe and detect by naked eyes or a magnifier, the method has low efficiency and high omission factor, and the eye fatigue of workers is easy to cause by using the naked eye for inspection, which is not beneficial to the health of eyes.

Accordingly, the prior art is deficient and needs improvement.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a liquid crystal display module open-circuit short-circuit detection system to improve the detection efficiency.

The technical scheme of the invention is as follows: an open circuit and short circuit detection system for a liquid crystal display module comprises: the device comprises an MCU, a register electrically connected with the MCU, a current detection circuit electrically connected with the MCU, an auxiliary circuit electrically connected with the current detection circuit and an audible and visual alarm device electrically connected with the MCU. The current detection circuit is used for detecting the current flowing through the auxiliary circuit, the MCU sends a detection signal and a clock signal to the register, processes data of the current detection circuit and starts the audible and visual alarm device, and when the detected module is in an open circuit, a short circuit or a normal state, current values generated by the auxiliary circuit are different.

The register is an 8-bit serial-in and parallel-out shift register and comprises 8 pins, and the register mainly converts serial data sent by the MCU into parallel data and sequentially outputs the parallel data through the 8 pins.

The auxiliary circuit is provided with a triode corresponding to each pin of the liquid crystal display module to be tested, if the tested pin of the liquid crystal display module is normal (i.e. no open circuit or short circuit exists), the triode corresponding to the pin is switched on, if the tested pin is open circuit, the triode corresponding to the pin is not switched on, and if the tested pin and the adjacent pin are short circuit, the triodes corresponding to the two pins are switched on at the same time.

Audible-visual alarm includes audible alarm and shows alarm, and when being surveyed liquid crystal display module normal time, this audible-visual alarm does not send out the police dispatch newspaper, when being surveyed liquid crystal display module appearance open circuit, audible alarm sounds and shows alarm and shows that alarm shows "open" typeface and the positional information who appears opening circuit, when being surveyed liquid crystal display module appearance short circuit, audible alarm sounds and shows alarm and show that alarm shows "short" typeface and the positional information who appears the short circuit.

By adopting the scheme, the invention is used for detecting whether the open circuit or short circuit phenomenon occurs to each pin of the liquid crystal display module, the liquid crystal display module to be detected is respectively and electrically connected with the register and the auxiliary circuit, the MCU sends a detection signal to the register, the register immediately sends a signal to the module to be detected, the current values generated by the auxiliary circuit under the three conditions of open circuit, short circuit or normal state of the module to be detected are different, the current detection circuit detects the current value generated by the auxiliary circuit, the MCU compares the current value with a standard current value, if the open circuit or short circuit occurs, the current value deviates from the standard current value, and then the MCU drives the audible and visual alarm device. The automatic detection liquid crystal display module replaces the original manual detection method, greatly improves the detection efficiency, has low detection misjudgment rate and is more reliable than manual detection, and reduces the reject ratio of products.

Drawings

FIG. 1 is a system framework diagram of the present invention.

Detailed Description

The invention is described in detail below with reference to the figures and the specific embodiments.

Referring to fig. 1, the present invention provides a system for detecting an open circuit and a short circuit of a liquid crystal display module, including: the device comprises an MCU, a register electrically connected with the MCU, a current detection circuit electrically connected with the MCU, an auxiliary circuit electrically connected with the current detection circuit and an audible and visual alarm device electrically connected with the MCU. The auxiliary circuit is provided with a triode corresponding to each pin of the liquid crystal display module to be detected, when the detected module is in an open circuit state, a short circuit state or a normal state, the current values generated by the auxiliary circuit are different, the current detection circuit is used for detecting the current flowing through the auxiliary circuit, and the MCU sends a detection signal and a clock signal to the register, processes the data of the current detection circuit and starts the audible and visual alarm device.

The register is an 8-bit serial-in parallel-out shift register, and comprises 8 pins from D0 bit to D7 bit, the register mainly converts serial data sent by the MCU into parallel data, and the parallel data are sequentially output through the 8 pins, so that IO port resources of the MCU can be saved by the register.

This system detects each pin of module under test one by one, and its theory of operation is as follows: after the system is powered on, the MCU sends a high-level detection signal to the register, then sends a clock signal to the register, at the rising edge of the clock signal, the register outputs the detection signal received from the MCU by a DO bit, and the DO bit outputs the high level because the detection signal is the high level.

When the pin of the tested module is normal (no open circuit or short circuit), the triode corresponding to the pin in the auxiliary circuit can be switched on by the high level signal, the current flowing through the resistor in the auxiliary circuit can be calculated by the supplied voltage and the resistance value of the resistor, the detected current value is sent to the MCU by the current detection circuit, the MCU compares the detected current value with the set standard value, and the MCU does not start the audible and visual alarm device if the current value is within the range of the standard value.

When the pin of the tested module is open, the high-level detection signal can not enable the triode corresponding to the pin in the auxiliary circuit to be switched on, the auxiliary circuit is in an open state, no current flows through the resistor of the auxiliary circuit (the current value is zero), and after the current value is compared with the standard value, the MCU drives the sound alarm device to give an alarm and drives the display alarm device to display open and open characters and open-circuit position information.

When the pin of the tested module is in short circuit with the adjacent pin, the triodes corresponding to the two pins in the auxiliary circuit can be simultaneously switched on, the resistance values of other elements in the auxiliary circuit can be reduced, the current flowing through the resistor can be increased, and after the MCU compares the current value with the standard value, the sound alarm device is driven to give an alarm and drive the display alarm device to display the short character and the position information of the short circuit.

When the test of the first pin of the tested module is finished, the MCU sends a low-level detection signal to the register, then sends a clock signal to the register, when the D1 bit of the register outputs the last clock signal, the D0 bit outputs the level (namely high level), the DO bit outputs the low-level detection signal newly received from the MCU, the D1 bit corresponds to the next pin of the tested module, the detection principle is the same as the previous pin, and so on, if the pins of the tested module are too many, the register and the auxiliary circuit can be added.

In summary, the invention is used for detecting whether each pin of the liquid crystal display module has an open circuit or a short circuit, the liquid crystal display module to be detected is respectively electrically connected with the register and the auxiliary circuit, the MCU sends a detection signal to the register, the register immediately sends a signal to the module to be detected, the current values generated by the auxiliary circuit in the three conditions of open circuit, short circuit or normal state of the module to be detected are different, the current detection circuit detects the current value generated by the auxiliary circuit, the MCU compares the current value with a standard current value, if an open circuit or short circuit occurs, the current value deviates from the standard current value, and then the MCU drives the audible and visual alarm device to alarm. The automatic detection liquid crystal display module replaces the original manual detection method, greatly improves the detection efficiency, has low detection misjudgment rate and is more reliable than manual detection, and reduces the reject ratio of products.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a liquid crystal display module assembly short circuit detection system that opens circuit which characterized in that includes: the device comprises an MCU, a register electrically connected with the MCU, a current detection circuit electrically connected with the MCU, an auxiliary circuit electrically connected with the current detection circuit and an audible and visual alarm device electrically connected with the MCU, a liquid crystal display module to be tested is respectively electrically connected with the register and the auxiliary circuit, the current detection circuit is used for detecting the magnitude of current flowing through the auxiliary circuit, the MCU sends a detection signal and a clock signal to the register, processes data of the current detection circuit and starts the audible and visual alarm device, the MCU sends the detection signal to the register, the register immediately sends a signal to the liquid crystal display module to be tested, the auxiliary circuit is provided with a triode corresponding to each pin of the liquid crystal display module to be tested, if the tested pin of the liquid crystal display module is normal, the triode corresponding to the pin is switched on, if the tested pin is open-circuited, the triode corresponding to the pin is not switched on, and if the tested pin and the adjacent pin are short-circuited, the triodes corresponding to the two pins are simultaneously switched on; when the liquid crystal display module is open-circuited, short-circuited or normal, the current values generated by the auxiliary circuits are different.

2. The system according to claim 1, wherein the register is an 8-bit serial-in parallel-out shift register, which includes 8 pins, and the register mainly converts serial data from the MCU into parallel data, and sequentially outputs the parallel data from the 8 pins.

3. The system for detecting the open circuit and the short circuit of the liquid crystal display module according to claim 1, wherein the audible and visual alarm device comprises an audible alarm device and a display alarm device.