12 Nov
Displays

Pros and Cons of Resistive Touchscreens

A resistive touch screen is made of a glass substrate as the bottom layer and a film substrate (normally, clear poly-carbonate or PET) as the top layer, each coated with a transparent conductive layer (ITO: Indium Tin Oxide), separated by spacer dots to make a small air gap. The two conducting layers of material (ITO) face each other. When a user touches the part of the screen with finger or a stylus, the conductive ITO thin layers contacted. It changes the resistance. The RTP controller detects the change and calculate the touch position. The point of contact is detected by this change in voltage.

Pros of Resistive Touchscreen

One of the main reasons why resistive touch panels still exist is its simple manufacturing process and low production cost. The MOQ (Minimum Order Quantity) and NRE (Non-Recurring Expense) are low. The driving is simple and low cost. The power consumption is low too. Resistive touch panel also immune to EMI well. Although it can’t use cover lens at the surface, the overlay can make it flexible for designs.

Resistive touchscreens offer an unparalleled level of durability. Manufacturing companies, restaurants and retailers often prefer them over other types of touchscreens for this very reason. With their durable construction, resistive touchscreens can withstand moisture and stress without succumbing to damage.

You can control a resistive touchscreen using a stylus or while wearing gloves. Most capacitive touchscreens only register commands performed with a bare finger (or a special capacitive stylus). If you use a stylus or a gloved finger to tap the interface, the capacitive touchscreen won’t respond to your command. Resistive touchscreens register and respond to all forms of input, though. You can control them with a bare finger, a gloved finger, a stylus or pretty much any other object.

Cons of Resistive Touchscreen

The biggest advantages for resistive touch panel are its touch experience and clarity. It can only be used for single touch, no gestures or multi-touch. False touches can be generated if using two or more fingers to touch it.

Resistive touch panel’s transparency is relatively low. In order to prevent Newton rings or fingerprint mark, sometimes AG(anti-glare) film has to be used to make it look more smoky. Optical bonding can’t be used for RTP. The surface of resistive touch panel is soft and easily get scratched.

There are still a few potential cons associated with resistive touchscreens. When compared to capacitive touchscreens, resistive touchscreens aren’t as sensitive. They are still responsive, but you’ll have to tap or press the interface with greater force for a resistive touchscreen to recognize your input.

Resistive touchscreens usually offer lower display resolutions than capacitive touchscreens. Granted, not all applications require a high-resolution display. If a touchscreen is used as a point-of-sale (POS) system in a retail environment, for example, resolution shouldn’t be a concern.

If you have any questions about Orient Display capacitive touch panels. Please feel free to contact: Sales Inquiries, Customer Service or Technical Support.

10 Nov
Displays

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.

01 Nov
Displays

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 dead

    LCD 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

28 Sep
Displays

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.

18 Sep
Displays

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.

15 Sep
Displays

Types of TFT LCD Technology

TFT (Thin Film Transistor) LCD (Liquid Crystal Display) dominates the world flat panel display market now. Thanks for its low cost, sharp colors, acceptable view angles, low power consumption, manufacturing friendly design, slim physical structure etc., it has driven CRT(Cathode-Ray Tube) VFD ( Vacuum Fluorescent Display) out of market, squeezed LED (Light Emitting Diode) displays only to large size display area. TFT LCD displays find wide applications in TV, computer monitors, medical, appliance, automotive, kiosk, POS terminals, low end mobile phones, marine, aerospace, industrial meters, smart homes, handheld devices, video game systems, projectors, consumer electronic products, advertisement etc. For more information about TFT displays, please visit our knowledge base.

What we are talking about TFT LCD, it is a LCD that uses TFT technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven LCDs with a few segments without TFT in each pixel.

There are many types of TFT LCD Technology. Different TFT LCD technology has different characters and applications.

TN (Twisted Nematic) Type

The TN type TFT LCD display is one of the oldest and lowest cost type of LCD display technology. TN TFT LCD displays have the advantages of fast response times, but its main advantages are poor color reproduction and narrow viewing angles. Colors will shift with the viewing angle. To make things worse, it has a viewing angle with gray scale inversion issue. Scientist and engineers took great effort trying to resolve the main genetic issues. Now, TN displays can look significantly better than older TN displays from decades earlier, but overall TN TFT LCD display has inferior viewing angles and poor color in comparison to other TFT LCD technologies.

IPS (In-plane switching) Type

IPS TFT LCD display was developed by Hitachi Ltd. in 1996 to improve on the poor viewing angle and the poor color reproduction of TN panels. Its name comes from its in-cell twist/switch difference compared with TN LCD panels. The liquid crystal molecules move parallel to the panel plane instead of perpendicular to it. This change reduces the amount of light scattering in the matrix, which gives IPS its characteristic of much improved wide viewing angles and color reproduction. But IPS TFT display has the disadvantages of lower panel transmission rate and higher production cost compared with TN type TFT displays, but these flaws can’t prevent it to be used in high end display applications which need superior color, contrast, viewing angle and crispy images.

MVA (Multi-Domain Vertical Alignment) Type

Fujitsu invented Multi-domain Vertical Alignment (MVA) technology.

The mono-domain VA technology is widely used for monochrome LCD displays to provide pure black background and better contrast, its uniformly alignment of the liquid crystal molecules makes the brightness changing with the viewing angle.
MVA solves this problem by causing the liquid crystal molecules to have more than one direction on a single pixel. This is done by dividing the pixel into two or four regions – called domains – and by using protrusions on the glass surfaces to pretilt the liquid crystal molecules in the different directions. In this way, the brightness of the LCD display can be made to appear uniform over a wide range of viewing angles.

MVA is still used in some applications but it is gradually replaced by IPS TFT LCD Display.

AFFS (Advanced Fringe Field Switching) Type

This is an LCD technology derived from the IPS by Boe-Hydis of Korea. Known as fringe field switching (FFS) until 2003, advanced fringe field switching is a technology similar to IPS offering superior performance and color gamut with high luminosity. Color shift and deviation caused by light leakage is corrected by optimizing the white gamut, which also enhances white/grey reproduction. AFFS is developed by Hydis Technologies Co., Ltd, Korea (formally Hyundai Electronics, LCD Task Force).

In 2004, Hydis Technologies Co., Ltd licensed its AFFS patent to Japan’s Hitachi Displays. Hitachi is using AFFS to manufacture high end panels in their product line. In 2006, Hydis also licensed its AFFS to Sanyo Epson Imaging Devices Corporation. (Reference)

The AFFS is similar to the IPS in concept; both align the crystal molecules in a parallel-to-substrate manner, improving viewing angles. However, the AFFS is more advanced and can better optimize power consumption. Most notably, AFFS has high transmittance, meaning that less of the light energy is absorbed within the liquid crystal layer and more is transmitted towards the surface. IPS TFT LCDs typically have lower transmittances, hence the need for the brighter backlight. This transmittance difference is rooted in the AFFS’s compact, maximized active cell space beneath each pixel.

AFFS has been used in high end LCD applications, like high end cell.phone because of its superb contrast, brightness and color stability.

If you have any questions about Orient Display technologies and products, feel free to contact our engineers for details.

 

Reference:

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15 Sep
Displays

How to choose a TFT LCD Display Module?

TFT (Thin Film Transistor) LCD (Liquid Crystal Display) dominates the world flat panel display market now. Thanks for its low cost, sharp colors, acceptable view angles, low power consumption, manufacturing friendly design, slim physical structure etc., it has driven CRT(Cathode-Ray Tube) VFD ( Vacuum Fluorescent Display) out of market, squeezed LED (Light Emitting Diode) displays only to large size display area. TFT LCD displays find wide applications in TV, computer monitors, medical, appliance, automotive, kiosk, POS terminals, low end mobile phones, marine, aerospace, industrial meters, smart homes, handheld devices, video game systems, projectors, consumer electronic products, advertisement etc. For more information about TFT displays, please visit our knowledge base.

There a lot of considerations for how to choose a most suitable TFT LCD display module for your application. Please find the check list below to see if you can find a right fit.

Size

  • It is the start point for every project. There are two dimensions to consider: outside dimension (width, height, thickness) and AA (active area or pixel area). Orient Display’s standard product line ranges from 1.0” to 32”. Our OLED size can go down to 0.66” which fit for wearable devices.

Resolution

  • Resolution will decide the clearance. Nobody likes to see a display showing pixel clearly. That is the reason for better resolution, going from QVGA, VGA to HD, FHD, 4K, 8K. But higher resolution means higher cost, power consumption, memory size, data transfer speed etc. Orient Display offers low resolution of 128×128 to HD, FHD, we are working on providing 4K for our customers. For full list of resolution available, please see Introduction: LCD Resolution

Aspect Ratio or Orientation

  • Orientation of either landscape or portrait has to be taken into consideration. Beside Aspect Ratio is also very important. You might be satisfied with 4:3 in the past, now, you might be willing to trying wider screen like 16:9 or even 21:9.

Brightness

  • TFT screen brightness selection is very important. You don’t want to be frustrated by LCD image washout under bright light or you drain the battery too fast by selecting a super brightness LCD but will be used indoor only. There are general guidance listed in the table below.

Orient Display offers standard brightness, medium brightness , high brightness, and high end sunlight readable IPS TFT LCD display products for our customers to choose from.

Viewing Angle

  • If the budget is tight, TN type TFT LCD can be chosen but there is viewing angle selection of either 6 o’clock or 12 o’clock. Gray scale inversion needs to be taken of carefully. If a high-end product is designed, you can pay premium to select IPS TFT LCD which doesn’t have the viewing angle issue.

Contrast Ratio

  • It is similar to viewing angle selection, TN type TFT LCD has lower contrast but lower cost, while IPS TFT LCD has much high contrast but normally with higher cost. Orient Display provides both selections.

Temperature

  • Normal TFT LCD displays provide wide enough temperature range for most of the applications. -20 to 70oC. But there are some (always) outdoor applications like -30 to 80oC or even wider, special liquid crystal fluid has to be used. Heater is needed for operating temperature requirement of -40oC. Normally, storage temperature is not an issue, many of Orient Display standard TFT display can handle -40 to 85oC, if you have any questions, feel free to contact our engineers for details.

Power Consumption

  • Power consideration can be critical in some hand-held devices. For a TFT LCD display module, backlight normally consumes more power than other part of the display. Dimming or totally shutdown backlight technology has to be used when not in use. For some extreme power sensitive application, sleep mode or even using memory on controller consideration has to be in design. Feel free to contact our engineers for details.

Interface

Orient Display provides a wide variety of interfaces, HDMI, RGB, LVDS, MIPI, SPI, RS232 and Parallel MCU(6800,8080).

  • Genetic Interfaces: Those are the interfaces which display or touch controller manufacturers provide, including parallel, MCU, SPI(,Serial Peripheral Interface), I2C, RGB (Red Green Blue), MIPI (Mobile Industry Processor Interface), LVDS (Low-Voltage Differential Signaling), eDP ( Embedded DisplayPort) etc. Orient Display has technologies to make the above interface exchangeable.
  • High Level Interfaces: Orient Display has technologies to make more advanced interfaces which are more convenient to non-display engineers, such as RS232, RS485, USB, VGA, HDMI etc. more information can be found in our serious products. TFT modules, Arduino TFT display, Raspberry Pi TFT display, Control Board.

Touch Panel

Touch panels have been a much better human machine interface which become widely popular. Orient Display has been investing heavy for capacitive touch screen sensor manufacturing capacity. Now, Orient Display factory is No.1 in the world for automotive capacitive touch screen which took around 18% market share in the world automotive market.

Orient can provide the traditional GG (Glass Glass) touch screen, OGS (One Glass Solution) touch screen, and PG (Plastic Glass) touch screen.

Based on the above three types of touch panel technology, Orient Display can also add different kinds of features like different material glove touch, water environment touch, salt water environment touch, hover touch, 3D (force) touch, haptic touch etc. Orient Display can also provide from very low cost fixed area button touch, single (one) finger touch, double finger (one finger+ one gesture) touch, 5 finger touch, 10 points touch or even 16 points touch

Considering the different shapes of the touch surface requirements, Orient Display can produce different shapes of 2D touch panel (rectangle, round, octagon etc.), or 2.5D touch screen (round edge and flat surface) or 3D (totally curved surface) touch panel.

Considering different strength requirements, Orient Display can provide low cost chemical tampered soda-lime glass, Asahi (AGC) Dragontrail glass and Corning high end Gorilla glass. With different thickness requirement, Orient Display can provide the thinnest 0.5mm OGS touch panel, to thickness more than 10mm tempered glass to prevent vandalizing, or different kinds of plastic touch panel to provide glass piece free (fear) or flexible substrates need.

Of course, Orient Display can also offer traditional RTP (Resistive Touch Panel) of 4-wire, 5-wire, 8-wire through our partners, which Orient Display can do integration to resistive touch screen displays.

Fully, Partial or Semi-Custom Solution

If you can’t find a very suitable TFT LCD Display in our product line, don’t be discouraged. The products listed on our website is only small part of standard products. We have thousands of standard products in our database, feel free to contact our engineers for details.

If you like to have a special display, Orient Display is always flexible to do partial custom solution. For example, to modify the FPC to different length or shape, or use as fewer pinouts as possible, or design an ultra-bright LCD display, or a cover lens with your company logo on it, or design an extreme low power or low cost TFT display etc. our engineers will help you to achieve the goals. The NER cost can start from hundreds of dollars to Thousands. In rare case, it can be tens of thousands of dollars.

A fully custom TFT LCD panel can have very high NRE cost. Depending on the size of the display, quantity and which generation production line to be used. The tooling cost can start from $100,000 to over $1M.

If you have any questions about Orient Display technologies and products, feel free to contact our engineers for details.

 

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15 Sep
Displays

Pros and Cons of TFT Displays

TFT (Thin Film Transistor) LCD (Liquid Crystal Display) we are talking here is TN (Twisted Nematic) type TFT displays which is align with the term in the TV and computer market. Now, TFT displays have taken over the majority of low-end color display market. They have wide applications in TV, computer monitors, medical, appliance, automotive, kiosk, POS terminals, low end mobile phones, marine, aerospace, industrial meters, smart homes, consumer electronic products etc. For more information about TFT displays, please visit our knowledge base.

Talking about Pros and Cons of TFT displays, we need to clarify which display they are compared to. To some displays, TFT displays might have advantages, but compared with another display, the same character might become the disadvantages of TFT displays. We will try our best to make clear as below.

Pros of TFT Displays

  • Less Energy Consumption: Compared with CRT(Cathode-Ray Tube) VFD ( Vacuum Fluorescent Display) and LED (Light Emitting Diode) display, which made laptop possible.
  • Good visibility and color: Compared with old CSTN (Color Super Twisted Nematic) or passive LCDs
  • Good response time and viewing angle: Compared with old CSTN or passive LCDs
  • Good cost: Compared with high end IPS (In-Plane Switching) LCD displays, AMOLED (Active Matrix Organic LED) displays and recent micro-LED display.
  • Excellent physical design. TFT displays are very easy to design and integrated with other components, such as resistive and capacitive touch panels (RTP, CTP, PCAP) etc.
  • Minimum Eye Strain: Because TFT panel itself doesn’t emit light itself like CRT, LED, VFD. The light source is LED backlight which is filtered well with the TFT glass in front for the blue light.
  • Space efficient design (can be placed anywhere in your workspace on a rotational mount so you can turn it in all directions).

Cons of TFT Displays

  • More Energy Consumption: Compared with monochrome displays and OLED (PMOLED and AMOLED) display, which makes TFT displays less attractive in wearable device.
  • Poor color saturation: Compared with IPS LCD displays and AMOLED displays.
  • Poor response time and viewing angle: Compared with IPS LCD displays, AMOLED displays and recent micro-LED display. TFT displays still need to note viewing angle of 6 o’clock or 12 o’clock in the datasheet and still have the gray scale inversion issue.
  • High tooling cost: Depending on which generation production line to produce and also depending on its size. Building a TFT display fab normally need billions of dollars. For a big size display which needs high generation production line to produce. The NRE cost can be millions dollars.
  • Sunlight Readability: Because it is very expensive to produce transflective TFT LCD displays, in order to be readable under the sunlight, very bright LED backlight (> 1,000 nits) has to be used. The power needed is high and also need to deal with heat management. If used together with touch panel, expensive optical bonding (OCA or OCR) and surface treatment (AR, AF) technologies have to be used.

If you have any questions about Orient Display technologies and products, feel free to contact our engineers for details.

 

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08 Sep
Control Board, Displays

How to use Graphic LCD Displays with Raspberry Pi?

How to connect Graphic LCD to Raspberry PI?

The article shows how to hook up a 128×64 graphics LCD display to a Raspberry Pi.

LCD used is a 128×64 with LCD controller of ST7565. It can be powered directly from the Raspberry Pi 3.3V rail. It requires 5 GPIO pins for data.

The schematic is, CS (Chip Select), RST(Reset) and A0 (Register Select) can be connected to any 3 GPIO pins. In this example, 8,24 and 25 are default values. Different values can be specified as parameters when instantiating the ST7565 Python class. SCLK (Serial Clock) on the GLCD goes to GPIO 11 which is the Pi’s serial clock. SID (Serial Input Data) on the GLCD goes to GPIO 10 on the Pi which is MOSI. GPIO 10 and 11 must be used for SID and SCLK. Vdd is connected to a 3.3V pin on the PI and the grounds are also connected.

The LCD has a RGB backlight. The LED pins can go to GPIO’s 16,20 and 21. To control the color from the Pi, specifying RGB pins when instantiate the ST7565 class. The resistors must be placed in series to limit the current to prevent LED breakdown. The LED brightness can be changed by using different values of resistors. It will be best to adjust the current to be around 20mA, of course, different values will result in a different mix of colors. It is very difficult to mix a pure white color. Please calculate the resistor value carefully, at 40mA, the LED brightness will decrease sharply with time, with the current of close to 60mA, the LED might be breakdown and be permanently damaged.

How to program a Graphic LCD?

The display is 128 pixels horizontal by 64 pixels vertical. The LCD can be broken into 8 horizontal pages. They are numbered from 3 to 0 and 7 to 4 up to down. Each page includes 128 columns and 8 rows of pixels. To address the pixels, specifying the page and column number, and send a byte to fill 8 vertical pixels at once.

The display has SPI (Serial Peripheral Interface) to connect to Pi. SPI requires 3 lines MOSI, MISO and Clock. The Pi is the master and the GLCD is the slave. In this example, Only writing to GLCD and not ready, so the connection to MOSI and Clock lines are needed. MOSI is the output from the Pi to the GLCD and the Clock synchronizes the timing.

  1. Enable SPI on Raspberry Pi first
  2. From the raspi-config menu, select Advanced Options, then SPI. Then select Yes for “ Would like the SPI interface to be enabled”. Hit OK, Reboot. Select Yes for “ the SPI kernel module to be loaded by default”. Reboot the Pi after enabling SPI. Then test SPI using IsmodIt should return SPI_bcm2708 or spi_bcm2835 depending on the Pi version. The python SPI library requires python2.7 dev which can be installed with apt-get install:
  3. The Python SPI library is called py-spidev. It can be installed using git:GLCD Python library for the Pi can be downloaded from the GitHub site.
  4. The main ST7565 library (st7565.py) handles drawing, text & bitmaps, and a font module (xglcd_font.py) to load X-GLCD fonts. Here are the basic drawing commands which to create points, lines, rectangles, circles, ellipses, and regular polygons:For more details, please refer to the reference below or contact our engineers.
23 Jul
Displays

TFT LCD Panel (Glass) Manufacturers Introduction

TFT LCD Panel (Glass) Manufacturers Introduction

 

 

Starting from the 2nd quarter of 2021, the LCD panel prices have kept increasing. We expect that the high prices will keep for at least 6 months. There are a lot of manufacturers of making LCD modules but there are only a few LCD panel or LCD glass manufacturers in the world. The reasons are 1) In order to build a LCD panel fab, billions of dollars of the equipment investment is needed; 2) The technology threshold is high. There are a lot of patent traps on the way; 3) Once in production, the fab has to keep running otherwise it is easy to lose money because of the heavy investment and the high pay for the engineers; 4), The worst is that the manufacturers have keep on investment in order to keep the technology and price competitive.   Let’s take a look of these LCD panel manufacturers.

AUO (AU Optrinics Corporation，友达光电):

In Taiwan.  It was formed in 2001 by the merger of Acer Display Technology Inc and Unipac Optoelectronics Corporation. It has G3.5 to G8.5 production lines.

 

BOE (Beijing Oriental Electronics Group Co., Ltd，京东方):

In China. The biggest LCD panel manufacturer in the world now.  BOE has G4 (Chengdu), G5 (Beijing), G5.5 (Ordos), G6 (Hefei, Chengdu, Mianyang, Dalian), G8 (Beijing, Hefei, Chongqing), Fuqing, Dalian, Chongqing) and 10.5 (Hefei) production lines.

 

CSOT (China Star Optoelectronics Technology，华星光电):

In China. It was joint ventured by TCL and Shenzhen Government. It mainly focusses on TV and cell phone screens. It has G6 (Shenzhen), G8.5 (Shenzhen, Suzhou,Wuhan) and G11 (Shenzhen) production lines.

 

CSOT (China Star Optoelectronics Technology,华星光电):

In China. It was joint ventured by TCL and Shenzhen Government. It mainly focusses on TV and cell phone screens. It has G6 (Shenzhen), G8.5 (Shenzhen, Suzhou,Wuhan) and G11 (Shenzhen) production lines.

 

CTC (Century Technology Shenzhen Co Ltd, 深超光电):

In China. CTC is the joint ventured by Foxconn and Shenzhen Government.  CTC has a G5 production line.

 

Giantplus Technology (凌巨科技):

In China, In 2019, it was acquired by Toppan in Japan. Ortus Technology holds 53.1% Giantplus shares. Giantplus has a G3 and a G4 production lines.

 

Hannstar (HSD, HannStar Display Corporation, 瀚宇彩晶):

In Taiwan. Hannstar has a G5 IPS production line.

 

HKC (惠科股份):

In China. HKC mainly produces LCD panels for monitors. HKC has 4 G8.6 production lines in Chongqing, Chuzhou, Mianyang, Changsha.

 

Innolux Corp (INX, 群创光电):

In Taiwan. One of the daughter company of Foxconn/Hon Hai.  In 2010, it bought the then famous LCD manufacturer, ChiMei, then changed its name to Innolux. It has G7.5 production lines.

 

IVO (InfoVision Optoelectronics (Kunshan) Co.,LTd. 龙腾光电):

IVO mainly produces laptop LCD panels. IVO has G5 production line.

 

JDI (Japan Display Inc, 日本显示):

In Japan. Joint ventured by Sony, Hitachi and Toshiba in 2011. It mainly produces smaller size panels. JDI has G6 production line.

 

Laibo (Shenzhen Laibao Hi-Tech Co.,Ltd, 莱宝高科):

Laibo has a G8.5 (Wuhan) and a G2.5 (Shenzhen) production lines.

 

LG.Philips Displays (LGD乐金电子):

In Korea and China. It is used to be the 2nd biggest TFT LCD manufacturers. LG also planned to stop the production but delayed the plan after the price increased. LG has G7.5 and G8.5 (Guangzhou) production lines.

 

Mantix Display Technology Co.,Ltd (华彩佳):

In China. Original Matix is the partner of CPT (Chunghwa Picture Tubes 中华映管). After CPT filed bankruptcy in 2019, Mantix took over CPT G6 production line.

 

Panasonic (松下):

In Japan. Panasonic has a G8.5 production line.

 

Panda (Nanjing CEC Panda LCD Technology Co.，Ltd. ,中电熊猫):

In China.  It got the technology from Sharp. It mainly produces LCD panels for TV.

 

Samsung Display （SDC,三星显示):

In Korea. It used to be the biggest TFT LCD manufacturers before it was dethroned by BOE in 2019. Because of tough competition, Samsung planned to stop the production in 2021 but delayed because the price increase during the pandemic.  Samsung has G7 and G8.5 production lines.

 

Shanghai Hehui Photoelectric Co., Ltd (上海和辉光电):

Hehui also produces AMOLED only and It has a G4.5 LTPS AMOLED production line.

 

Sharp （夏普):

In Japan and China. The pioneer and queen of LCD industry. Because of high cost and tough competitor, Sharp was acquired by Foxconn/Hon Hai in 2016. Sharp has G8, G8.5(Suzhou), G10, G10.5 (Guangzhou) production lines.

 

Tianma Microelelctronics（TM,天马微电子):

In China and Japan. In 2011, Tianma acquired 70% share from NEC to rename as “NLT Technologies”. Tianma has G4.5 (Shanghai, Chengdu, Wuhan), G5 (acquired from SVA: SVA Information Industry Co.,Ltd.). G5.5 (Xianmen, Shanghai for AMOLED),  G6 (Xiamen, Wuhan for AMOLED).

 

Truly Opto-electronics (信利光电):

In China, Truly was mentioned to have a G4.5 for AMOLED and a G2.5 for TFT LCD production lines.

 

Visionox (维信诺):

Actually, Visionox doesn’t product LCD. It produces AMOLED and PMOLED only. It has a G5.5 AMOLED and a G6 flexible AMOLED production lines.

LCD Motherglass Generation Classifications
Generations Motherglass Size Notes
G1 320*400 \
G2 370*470 \
G3 550*650 15″/4pcs
G4 680*800 15″/6pcs
G4.5 730*920 15″/8pcs
G5 1100*1300 27″/6pcs
G5.5 1300*1500 27″/8pcs
G6 1500*1850 32″/8pcs, 37″/6pcs
G7 1950*2250 42″/8pcs, 46″/6pcs
G8 2160*2460 46″/9pcs, 52″/6pcs
G8.5 2200*2500 55″/6pcs
G10 2880*3100 65″/6pcs, 60″/8pcs
G10.5 2940*3370 65″/8pcs
G11 3000*3320 70″/8pcs

 

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