tft lcd failures quotation
One of the most common questions we get asked regarding TFT performance is related to pixel faults and ‘What makes a good or faulty panel?‘ If you inspect any TFT very closely you will find faults, but this does not mean you have a faulty panel. You will need to consider, firstly, the type of fault that might be exhibited:
As a guideline for you, here is the Samsung position as stated on their Cosmetic Outgoing Inspection Specification (TFT LCD : A Grade) where the number = the total number of pixel faults on the panel:
Please also remember that TFT panel quality and grade are often directly related to the number of pixel failures that may be allowable by the producer. If you are concerned about the number of pixel failures that are visible to the naked eye, then it may be time to upgrade your panel specification…
I am blocked because I have the same TFT as on the photo. I have to connect it to a pcb that use the same SPI for the display and for the touchscreen. I am using a ESP32 but I am not sure it is meaningful.
When the TFT_RST pin is defined as output and set to HIGH, the XPT2046 returns only a value equal to zero when I read it. Otherwise, it replies with values that seems OK (they change when I touch the screen).
Note: I have a friend that has the same TFT. He did not remove the diode (was not aware off this) and his TFT works just fine using exactly the same firmware and the same board.
In this Arduino touch screen tutorial we will learn how to use TFT LCD Touch Screen with Arduino. You can watch the following video or read the written tutorial below.
As an example I am using a 3.2” TFT Touch Screen in a combination with a TFT LCD Arduino Mega Shield. We need a shield because the TFT Touch screen works at 3.3V and the Arduino Mega outputs are 5 V. For the first example I have the HC-SR04 ultrasonic sensor, then for the second example an RGB LED with three resistors and a push button for the game example. Also I had to make a custom made pin header like this, by soldering pin headers and bend on of them so I could insert them in between the Arduino Board and the TFT Shield.
Here’s the circuit schematic. We will use the GND pin, the digital pins from 8 to 13, as well as the pin number 14. As the 5V pins are already used by the TFT Screen I will use the pin number 13 as VCC, by setting it right away high in the setup section of code.
I will use the UTFT and URTouch libraries made by Henning Karlsen. Here I would like to say thanks to him for the incredible work he has done. The libraries enable really easy use of the TFT Screens, and they work with many different TFT screens sizes, shields and controllers. You can download these libraries from his website, RinkyDinkElectronics.com and also find a lot of demo examples and detailed documentation of how to use them.
After we include the libraries we need to create UTFT and URTouch objects. The parameters of these objects depends on the model of the TFT Screen and Shield and these details can be also found in the documentation of the libraries.
So now I will explain how we can make the home screen of the program. With the setBackColor() function we need to set the background color of the text, black one in our case. Then we need to set the color to white, set the big font and using the print() function, we will print the string “Arduino TFT Tutorial” at the center of the screen and 10 pixels down the Y – Axis of the screen. Next we will set the color to red and draw the red line below the text. After that we need to set the color back to white, and print the two other strings, “by HowToMechatronics.com” using the small font and “Select Example” using the big font.
In recent years, TFT-LCD industry has developed rapidly. TFT- LCD is one of the essentials in daily life, which can be used in TV, laptop and cell phones in the market. TFT-LCD is currently manufacturing process in the event of failure, if it cannot be realtime identified and treatment, will cause the company"s production capacity can be reduced. Purchase of alarm management system and can real-time notify the manufacturing process failure to personnel to quickly solve the problem, so that the normal operation of manufacturing systems to play the company"s largest production efficiency. This study used the cause-effect grey relational analysis (CEGRA) to analyze the reasons for alarm message, find out its relevance and correct analysis classified. Finally, through CEGRA can help companies master the problem and deal with real-time.
On Apr 18, 2020, at 6:10 PM, Ira Lipton
That"s right Andy. I"m 99% certain that the external monitor had no display when the TFT failed. I"ll plug it in and recheck it over the next few days to be sure. If it was working I could use the radio.
On Apr 18, 2020, at 9:13 PM, Ira Lipton
If there is no display on the monitor then the DMU computer is likely the failure. The DMU PC module has an interface between it and the radio’s TFT. But the PC module has a direct VGA output. That is what is connected to the monitor port.
On Apr 18, 2020, at 9:13 PM, Ira Lipton
If there is no display on the monitor then the DMU computer is likely the failure. The DMU PC module has an interface between it and the radio’s TFT. But the PC module has a direct VGA output. That is what is connected to the monitor port.
That"s right Andy. I"m 99% certain that the external monitor had no display when the TFT failed. I"ll plug it in and recheck it over the next few days to be sure. If it was working I could use the radio.
If there is no display on the monitor then the DMU computer is likely the failure. The DMU PC module has an interface between it and the radio’s TFT. But the PC module has a direct VGA output. That is what is connected to the monitor port.
That"s right Andy. I"m 99% certain that the external monitor had no display when the TFT failed. I"ll plug it in and recheck it over the next few days to be sure. If it was working I could use the radio.
TFT LCD monitors are susceptible to glare and reflection from direct sunlight or high-bright applications. In almost all TFT LCDs there is an air gap between the TFT panel and the cover lens. Having an air gap causes repeat refraction between each component level of the display when in high-brightness installations. Reducing the reflection inside these components with optical bonding gives greater contrast and makes the screen more viewable in outdoor or high bright conditions without the need to increase the brightness of the screen itself.
Optical bonding is a process where a layer of resin is applied between the glass or touchscreen and TFT LCD TFT panel of a monitor, bonding them to make a solid laminate with no gaps or pockets of air. When choosing a screen for any project, you should evaluate the environment and operating conditions the screen will have to endure. Industrial grade screens and panel PCs are made rugged with all types of features available to withstand any type of application. One such feature available to consider is optical bonding.
When LCD displays are manufactured, including touchscreens, the front glass of the screen is layered onto the LCD module. This doesn’t present a problem in standard viewing environments, however in certain conditions, like with outdoor placement, the tiny gap between the 2 layers can impair viewing performance.
The display from an non-optically bonded monitor is created by the light of the LCD reflecting through the gap and then the outer glass of the screen. The light is interrupted and bends when it passes through the gap and glass of the screen and some of the light is actually reflected back to the LCD module, this is called refraction. This refraction through the layers impairs the intensity and clarity of the end image and thus lowers brightness and readability. By bonding the LCD module and glass together you remove the interruptions and chances for the light to be reflected back. More light gets through to the surface of the screen and therefore the image is brighter.
The same principle is applied when an external source of light hits the screen. With an non-bonded screen, the gap between the glass and LCD module creates opportunities for refraction which bounces external light back off the screen to the viewer as glare. When bonded together the light passes through the bonded layers and is absorbed somewhat into the screen. Optical bonding is therefore important in making screens sunlight readable.
The most obvious benefit to adding a resin bonding layer between the glass and LCD module is that it physically prevents dust and liquid ingress from getting between the two. The quality of manufacturing means that dust and water isn’t a big problem for screens in standard environments. What can be a problem however is condensation getting between the glass and LCD panel in environments with wide temperature ranges or fluctuating humidity. Condensation can cause screens to become foggy from moisture that penetrates the air gap. Again, the physical filling of the gap prevents this problem from arising. Optical bonding should therefore be considered for any outdoor application as well as indoor applications where consistent temperatures aren’t maintained.
When the voltage is applied to the electrode of the LCD, the light (brightness) passing through the LCD will change. The reaction time from its change to the stable time is called the light’s reaction time（response time), which divided into Tr and TF.
Tr refers to the reaction time of LCD when the voltage rises to a stable state (the time required for the light penetration rate to change from 10% to 90% after pressure). Tf refers to the reaction time of LCD when the voltage drops to a stable state(the time required for the light penetration rate to change from 90% to 10% after pressure).
Ms.Josey 
Ms.Josey