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Pros and Cons of Capacitive Touchscreens
Capacitive Touch Screen (PCAP)
Projected capacitive touchscreen contains X and Y electrodes with insulation layer between them. The transparent electrodes are normally made into diamond pattern with ITO and with metal bridge.
Human body is conductive because it contains water. Projected capacitive technology makes use of conductivity of human body. When a bare finger touches the sensor with the pattern of X and Y electrodes, a capacitance coupling happens between the human finger and the electrodes which makes change of the electrostatic capacitance between the X and Y electrodes. The touchscreen controller detects the electrostatic field change and the location.
Pros of Capacitive Touchscreen (CTP)
- Looks sharper and brighter
Capacitive Touch Screen uses glass substrate which has high transparency compared with plastic film used by resistive touch panels. Plus, optical bonding and glass surface treatment which make CTP good picture quality and contrast. - Better Human Machine Experience
Because capacitive touchscreens register touch via the human body’s electrical current, they require less operating pressure than resistive touch panel glass. It supports touch gestures and multi-touch which makes it much better user experience of touch. - Incredible durability
Because the cover glass is used in front which can be extremely high hardness (>9H), it is extremely durable for touch which can exceed 10 million touches. It also prevents from scratches and easy to clean which makes it prevailing resistive touch panels. - Size and Appearance
Capacitive touchscreen can be made for very large size (100 inches) and the cover lens can be decorated with different colors, shapes, holes to provide users flexible designs.
Cons of Capacitive Touchscreen (CTP)
- Cost
Capacitive Touchscreen manufacturing process is relatively more expensive and the cost can be high. - Immunity to Objects/Contaminants on Screen
Capacitive Touchscreen needs special design and uses special controllers to make it used in special applications, such as using glove to touch, or with water, salt water environment. The cost can be even higher. - Damage
The cover lens can crack. In order to prevent glass debris to fly, a film or optical bonding is needed in the manufacturing process to make the price even higher. - Interferes
Capacitive Touchscreen is easily to be affected by ESD or EMI, special designs have to be considered in the design which can drive the price higher. Special calibration has to be carried out with the help of the controller manufacturer. - Power and wake up
The power used in capacitive Touchscreen can be higher than resistive touch panel. Sometimes, a hot button has to be designed to wake up the touch function.
If you have any questions about Orient Display capacitive touch panels. Please feel free to contact: Sales Inquiries, Customer Service or Technical Support.
How to fix LCD display problems?
LCD screen display problem why does it occur?
Liquid crystal displays (LCDs) are the most widely used display technology. Their applications cover TV, mobile phone, appliances, automotive, smart home, industrial meters, consumer electronics, POS, marine, aerospace, military etc. LCD screen display problem can occur for several reasons.
- Effect of environmental conditions on the LCD assembly. Environmental conditions include both the effects of temperature and humidity, and cyclic loading.
- Effects of handling conditions on the LCD. Handling can include bending, repetitive shock, and drop loading conditions.
- Effect of manufacturing process. With the development of LCD for more than 40 years and the modern manufacturing equipment, this kind if defects are getting rear.
Common failures seen in LCDs are a decrease in screen contrast, non-functioning pixels or the whole display, and broken glass. Different kinds of LCD display problem need to have different kinds of fix methods or make the decision not worthwhile to repair.
LCD display problem – How to fix it?
- Broken glassIf you accidently drop the LCD and you find it broken on the surface but the display still works. You might just break the touch panel; you can find a repair house or find a youtube video to replace the touch panel. If you find the display not showing, especially you find the fluid leaking out. You need to reply the whole display modules.
- Dim LCD displayLCD can’t emit light itself. It uses backlight. Normally, the backlight is not fully driven, you can increase the LED backlight to make a dim LCD display brighter. But if you LCD display has been used for a long time, it is possible that the LED backlight has to be the end of life (not brightness enough) if you turn on 100% backlight brightness. In that case to fix LCD screen, you have to find a way to change the backlight. For some display, it is an easy job but it can be difficult for other displays depending on the manufacturing process.
- Image sticking (Ghosting)Sometimes, you will find the previous image still appearing at the background even if you change to another image. It is also called burn in. This kind of failure doesn’t need to repair by professionals. You can simply shut off the display overnight, this kind of problem will go away. Please do remember that displaying a static image for a long time should be avoided.
Display including backlight completely deadLCD screen display problem – the most common cases
With the modern manufacturing process and design, this kind of failure rarely happens. Normally, it is caused by no power. Please check if the battery dead or adapter (power supply) failure or even check if you have plug in firmly or with the wrong power supply. 99% the display will be back on.
- LCD has white screen – If a LCD has a white screen which means the backlight is good. Simply check your signal input sources which are the most causes. It can also be caused by the display totally damaged by ESD or excess heat, shock which make the LCD controller broken or the connection failure which has to be repaired by professionals.
- Blur ImagesAs the LCD images are made of RGB pixels, the screen shouldn’t be blur like old CRT displays. If you do see blur images, they might be caused by two reasons. 1) LCD has certain response time, if you are playing games or watch fast action movies, some old LCD displays can have image delays. 2) The surface of the LCD is made of a layer of plastic film with maximum hardness of 3H. If you clean the surface often or use the wrong detergent or solvent which cause the surface damage. To fix damage on LED screen it’s need to be changed with professionals.
If you have any questions about Orient Display displays and touch panels. Please feel free to contact: Sales Inquiries, Customer Service or Technical Support.
Check Also: Bistable LCD
Introduction of Lichee Pi
Introduction of Lichee Pi
The LicheePi is a delicate, single-board computer, running on the low-cost Allwinner V3S platform which is popularity in recent years. It can be used for beginners to learn Linux or for product development. it offers a wealth of peripherals (LCD, ETH, UART, SPI, I2C, PWM, SDIO…) and powerful performance.
Lichee Zero Lichee Nano
Lichee Pi Zero Lichee Pi Nano
| Features |
LICHEE PI ZERO |
LICHEE PI NANO |
| SoC | Allwinner V3S | Allwinner F1C100S |
| CPU | ARM Cortex-A7 | ARM9 |
| Operating Freq. | 1.2GHz | 408MHz |
| RAM | 64MB DDR2 | 32MB DDR2 |
| Storage | SPI Flash/Micro-SD | SPI Flash/Micro-SD |
Display
|
* Universal 40P RGB LCD FPC:
* Supported resolutions: 272×480, 480×800,1024×600 * Onboard RTP chip, supports a touch screen |
* Universal 40P RGB LCD FPC:
* Supported resolutions: 272×480, 480×800,1024×600 * Onboard RTP chip, supports a touch screen |
Interface
|
* SDIO x2 * SPI x1 * I2C x2 * UARTx3 * 100M Ether x1（include EPHY） * OTG USB x1 * MIPI CSI x1 * PWM x2 * LRADC x1 * Speakerx2 + Mic x1 |
* SDIO x1 * SPI x2 * TWIX x3 * UART x3 * OTG USB x1 * TV out* PWM x2 * LRADC x1 * Speakerx2 + Mic x1 |
Electrical Information |
Micro USB 5V, 2.54mm pins 3.3V~5V power supply; 1.27mm stamp hole power supply.
1GHz linux IDLE run 90~100mA; cpu-burn run ~180mA Storage Temperature -40~125 Operating Temperature -20~70 |
Micro USB 5V, 2.54mm pins 3.3V~5V power supply; 1.27mm stamp hole power supply.
408MHz linux IDLE run 90~54mA; with screen operating current ~250mA Storage Temperature -40~125 Operating Temperature -20~70 |
The temperature when running the Linux stress test is only slightly higher than the body temperature.
Lichee Pi support many OS such as: Linux, RT-Tread, Xboot or no OS.
Like most MCU, the Lichee Pi can connect to several low-speed interfaces, such as GPIO, UART, PWM, ADC, I2C, SPI, and more. Moreover, it can run other high-speed peripherals such as RGB LCD, EPHY, MIPI CSI, OTG USB, and more. The Lichee Pi has an integrated codec that allows direct connection to a headphone or microphone.
Display Connector:
The universal 40P LCD comes with a led back light and four-wire lines, electrical resistance touch, which is very suitable for display and interaction. A13 also supports four-wire resistance touch function, can carry out two-point touch detection.
This interface is compatible with the interface of ORIENT DISPLAY products.
RGB to VGA:
RGB to HDMI:
RGB to GPIO:
RGB to DVP CSI:
Lichee Pi Link:
https://dl.sipeed.com/
Wiki：maixpy.sipeed.com
Blog：blog.sipeed.com
Telegram group: https://t.me/sipeed
How does a Graphic LCD work?
An Introduction to Graphic LCD Displays
Graphic LCD Displays normally refer to monochrome graphics LCD displays or dot matrix LCD displays. Although color TFT (Thin Film Transistor) and OLED (Organic Light Emitting Diodes) displays to meet all the definitions of graphic LCD displays and can also be categorized as graphic LCD displays, monochrome graphics LCD displays have been in the market much earlier than color TFT displays and they become the legacy type of display. That is the reason that Graphic LCD displays only refer to monochrome, not the full color.
What are Graphic LCD Displays?
Compared with Character LCD Displays which can only display digits or alphanumeric, graphic LCD displays can display digits, alphanumeric, and graphics. They played very important roles in the early stages of LCD display history.
Graphic LCD displays are identified by the number of pixels in vertical and horizontal directions. For example, 128 x 64 dot matrix graphic display has 128 dots/pixels along the X axis, or horizontal, and 64 dots/pixels along the Y-axis or Vertical. Each of these dots sometimes referred to as a pixel, can be turned ON and OFF independently of each other. The customer makes use of software to tell each dot when to turn ON and OFF. The early engineering work has to light/map pixel by pixel, which is very tedious work. Thanks to the LCD controller advancement, Some Orient Display graphic LCD products have many images in the memory already which greatly helps engineers to reduce the workload and make the products much faster to the market. Please check with our engineers for details.
Orient Display provides dot matrix formats of 122×32, 128×64, 128×128, 160×32, 160×64, 160×160, 192×48, 192×64,202×32, 240×64, 240×160, 240×128, 282×128, 320×240 etc.
Graphic LCD Interface
There are some popular graphic LCD interfaces, such as 8 bit or 16 bit 6800 and/or 8080 MCU interface, 3 or 4 wire SPI interface, I2C interface etc.
Fluid Options of a Graphic LCD Display
There are many options for graphic LCD displays, all of them derived from STN (Super-Twisted Nematic Display). TN (Twisted Nematic Display) or HTN (High-performance TN) displays are rarely used in graphic LCD displays because of their poor contrast and narrow viewing angles.
- Positive displays can include: yellow-green STN, gray STN, positive FSTN;
- Negative displays can include: blue STN, negative FSTN, FFSTN, ASTN;
Backlight Options of a Graphic LCD Display
LCD itself can’t emit light. In order to be observed under the dim light, the backlight has to be used. Back to 10 years ago, Backlight can be LED (Light Emitting Diode), CCFL (Cold Cathode Fluorescent Lamps) or EL (Electroluminescent) backlight. Thanks to the development of LED technology, especially the breakthrough of the blue and white LED technologies, LED backlight dominates the market. LED backlight can be made either bottom lit and side lit with various colors For more information, please refer to Orient Display Jazz Graphic LCD Display and Backlights.
Graphic LCD Display Controller and Drivers
The LCD controller is a small microprocessor that converts the customer’s software code (aka firmware) to information that the LCD can understand. LCD Drivers control the complex AC voltage requirements for the LCDs and they need a LCD controller to keep refreshing the individual pixel information to their drive circuitry. These ICs will typically be integrated into the LCD Modules either by COG (Chip on Glass) or COB (Chip on Board) technologies.
Sitronix is the world’s biggest graphic LCD controller manufacturers. The headache for most engineers is that LCD controllers can EOL (End of Life) a lot. Please make sure to discuss with Orient Display engineers for the most updated information to keep 5-10 years supply life.
How to use a graphic LCD Display?
An Introduction to Graphic LCD Displays
Graphic LCDs (liquid crystal displays) have a special position in the display industry. With the fast development of gadgets and digital devices, manufacturers need the latest technologies and techniques to provide high-quality products and services.
Graphic LCD Displays normally refer to monochrome graphics LCD displays or dot matrix LCD displays. Although color TFT (Thin Film Transistor) and OLED (Organic Light Emitting Diodes) displays to meet all the definitions of graphic LCD displays and can also be categorized as graphic LCD displays, monochrome graphics LCD displays have been in the market much earlier than color TFT displays and they become the legacy type of display. That is the reason that Graphic LCD displays only refer to monochrome, not the full color.
Graphic LCD Interface
There are some popular graphic LCD interfaces, such as 8 bit or 16 bit 6800 and/or 8080 MCU interface, 3 or 4 wire SPI interface, I2C interface etc.
Applications
LCD modules are used in various devices and applications. They make it possible for mobile phones, laptops, and televisions to produce clear images. They can also be seen in watches, calculators, and digital readers to help users read text easily. Moreover, the automotive industry is utilizing this technology as well. Car manufacturers integrate them into interior designs to provide a display of various information and allow access to services such as GPS navigation.
Benefits
Low cost, easy to manufacture, low power consumption are the main benefits for monochrome graphic displays.
Graphic LCD tutorial
In this tutorial, the working and pinout of 128×64 graphical LCD AMG12864AR-B-Y6WFDY-AT-NV-Y (2.9″ 128×64 Graphic LCD Module) will be described. It has 128 columns and 64 rows, 128×64 has 128×64=8192 dots.
Graphical LCD controller
Graphical LCD is controlled by two S6B0108 controllers. A single S6B0108 controller is capable of controlling 4096 dots. So, for controlling a graphical LCD we need two S6B0108 controllers.
Further graphical LCD half’s division
Each half is further divided into 8 pages of equal sizes. Each page size is 8 rows and 64 columns. Each page contains 8*64=512 dots.
Page distribution in Pixels
Each page contains 64 pixels (64 columns and 8 rows). output on these pixels. Each pixel lights up when it is 0 and becomes off when it is 1. Each pixel contains 8 dots.
Graphical Lcd (128×64) Pinout
Please refer to Page 8 of the AMC12864A specification.
Graphical LCD pins are the same as other character LCDs. Only two new pins are introduced with the graphical LCD. These are CS1 and CS2. CS1 is chip select 1 it selects the first half or first S6B0108 controller of LCD. CS2 is chip select 2 it selects the second half or second S6B0108 controller of LCD. Both CS1 and CS2 are active low. By active-low I mean for selecting a first or second half, make its associated pin (CS1, CS2) low 0. All the other pins E (enable) R/W (read/write) RS or D/I (register select) works in the same way as for normal LCDs.
Like other LCDs we also first have to initialize graphical LCD.
Introduction to Orient Display Embedded Project
Introduction to Orient Display Embedded Project
Orient Display is one of the world’s leading display LCD display manufacturers which was founded in 1996 by executives more than 25 years of R&D and production experience. Besides display, Orient Display also focused on embedded technologies which are including ARM architecture and has accumulated rich experience in embedded products.
Now Orient Display Technical Services include hardware, software and consulting.
Our Hardware team make prototypes in the shortest time according to your design ideas and requirements. We specialize in the design of cost-effective or a complex high-performance board to meet your requirement for high reliability in a short development cycle.
– Schematic Design
– PCB Layout
– Industry Product Customization
Our Software team specializes in Linux-based ARM® designs, PowerPC and x86 processor, to name a few. As a complete solution provider for Linux, Android and WinCE in embedded systems, we can solve the end-to-end system-related problems of your products.
– System migration, optimization and tailoring
– Drive development
– Kernel Tailoring
– Porting LINUX KERNEL to ARM, PPC or x86 Board
– APP development (application, Linux QT, Linux C/++）
Our FAE team also provide you with a full range of technologies for your products or semi-finished products.
– We provide consultation on software & hardware resources of our products;
– We solve problems encountered during the use of software & hardware manuals of our products;
– OEM and ODM after-sales technical support;
– Data maintenance and update;
– Orient Display products are backed by our Lowest Price Guarantee.
Development Sequence
1. System Requirements Analysis
* Design tasks, goals, specifications
– This provided by our customers
* Functional and non-functional requirement
– Include system performance, cost, power consumption, volume, weight and other factors
2. Architecture Design
A good architecture is the key to the success of the design. In this step, it is often necessary to do following things:
- Select the main chip:
— ARM Cortex A, R or M, or PowerPc or ColdFire
- Determine the RTOS:
— Linux, uClinux, Vxworks, freeRTOS, WinCE
- Select Display:
— TFT Panel, Sunlight Readable TFT, LCD Glass Panels, Graphic LCD, OLED Display, Touch Panels, Embedded LCD display or Custom made display by Orient Display
- Programming language:
— c/c++, python, Java
- Development tools:
u-boot, busybox, QT, Ubuntu, stm32CubeIde, visual studio, android studio, keil uVision, RT-Tread studio
3. Hardware and Software Co-design
In order to shorten the product development cycle:
Hardware: We usually begin project from evaluation board such as orient display AIY-A002M, AIY-A003M and AIY-A005M. later will Customized board to fit project, discard parts which don’t need.
Software Development Sequence:
- We usually choose u-boot as Bootloader, it 1)init cpu to known state 2)init memory 3)init interrupt 4)init clock 5)load kernel to running address
- Configure Kernel:
1) configure kernel system: *memory management, *file systems, *device driver, *network stack, *I/O Systems
2) write I/O device driver *char device driver, *block device driver, *net device driver
- Select Applications:
*Select a user library *Build user application *Configure Initialization process *Build root FS
4. System Integration
Integrate the system’s software, hardware and execution devices together, debug, find and improve the errors in the unit design process.
5. System Test
Test the designed system to see if it meets the functional requirements given in the specification. The biggest feature of the embedded system development model is the comprehensive development of software and hardware.
In Conclusion
Orient Display has an amazing team of talented experts with the experience and capabilities to create an embedded display module from concept through to production.
If you have any questions, please contact our engineers at: tech@orientdisplay.com.