FAQ | Knowledge Base

• Technical

  • Backlight

    • EL (Electroluminescence) backlighting is also called an ELP (Electroluminescence Panel). This type of backlighting is a technology that uses colored phosphors, not heat, to generate light. EL backlights are very thin(slightly thicker then a credit card) and lightweight. They provide an even light across the entire display. A variety of colors is available with white being the most popular. EL backlights require voltages of 100VAC @ 400Hz which is supplied by an inverter that converts 5, 12 or 24 VDC input to the AC output. The half-life of EL backlights is much shorter than other backlighting technologies at 3k to 5k hours. Half-life is when the backlight is ½ as bright as when it was first turned on. Sometimes EL backlights emit a humming that is caused from the inverters used on the board. A film capacitor can be used to prevent this noise. One major disadvantage to an EL backlight is that it produces EM noise. The customer may need to shield their product to eliminate this interference.
    • The short answer: 50,000 to 70,000 hours for most colors except blue and white (5.7 to 8 years of continuous running). Blue and white are rated at 30K hours (3.4 years of continuous running). The long answer: There are two definitions in the industry for “lifetime” · Half-life: this is when the LED will be half as bright as when the LED was first turned on. · MTBF (Mean-time between failures). This is when there is a 50% chance that the LED will fail. There are many studies on the subject of ‘lifetime”. Each study claims a different number of hours. One thing to take into account is that as technology improves, the lifetime of the LED’s will become longer.
    • CCFL (Cold Cathode Fluorescent Lamp) backlights are a backlight with low power consumption and a very bright light. CCFL’s are most commonly produced as an edge lit backlight. This backlight uses a diffuser(similar to a lamp shade) to distribute the light evenly across the viewing area. CCFL’s do require an inverter to convert DC to AC. This is to supply the 270 to 300 VAC @ 35KHz that is used by the CCFL tube. CCFL backlights are used primarily in graphic displays. They have a (half-life)lifespan of 10K to 20K hours which is longer than an EL but shorter than an LED backlight.The biggest hang up with CCFL backlights is that the light output can be lowered by as much as 60% in cold weather. They require inverters to generate the 350VAC and inverters do not work well in cold temperatures. Another issue is the display is either ON or OFF, the brightness cannot be varied. CCFL’s also handle vibration poorly, vibrations can reduce the life expectance of the backlight by up to 50%.
    • The most likely cause is that the polarity is reversed. A LED backlight operates on DC (Direct Current). The backlight must be connected correctly. The positive side of the backlight must be connected to the positive side of the power supply.The positive side is called “A”. The other connection is called “K”, this is normally ground. If the polarity is reversed then the backlight will not work. The solution is to reverse the polarity. How? LCD’s that come with the LED backlight integrated into the display normally have pin 15 set as positive and pin 16 as ground. Please see diagram below. Your product may require pin 15 to be ground and pin 16 to be positive. If this is the case there are two jumper settings on the back of the LCD that allow the user to reverse the polarity. Please contact us for information on which jumper settings to reverse the polarity.
    An LCD backlight is a solution to make an LCD readable when there is not enough outside light. The LED backlight is the most common type of backlight used in character, static and mono graphic displays. The LED Backlight illuminates the LCD from the side or back of the display, hence the term Back-Light. Backlights are used in displays to increase visibility in low light conditions. Most LCD’s that are equipped with a backlight employ a diffuser(similar to a lamp shade) to provide a more even light from the LED’s.Advantages to LED backlights are: • Solid state, there are no moving parts to break • DC, there is no need for an inverter • No noise from the AC inverter, hence, no need for shielding • The customer can adjust the contrast through the use of a current limiting resistor.
    EL backlights have a half life of 5,000 hours (7 months of continuous running) Half Life is when the brightness of the backlight is ½ of what is was when it was first turned on.
    We find that the most popular backlighting for small LCD modules is LED. The definition of small LCD display is a character display ranging from an 8×1 LCD display up to a 40×4 LCD module. The popularity of LED side lit or LED back lit (Array lit LED) is due to the following advantages: • No noise that is found with AC applications such as EL backlight or CCFL backlight • Longer life • Variable brightness • Does not require an AC inverter. To increase the brightness of the LED backlight, change the value of the current limiting resistor. NOTE: The brighter the LED backlight, the shorter the lifetime of the backlight.
  The LED or EL backlight on Character LCD modules, Graphic LCD modules and Segment LCD modules have different levels of brightness depending on the type of polarizer that is installed. Here you can find additional information on LCD display polarizer’s .When ordering an FSTN display, STN display or TN display with a backlight you have the option of two polarizers: Transflective and Transmissive. The advantage of the transmissive polarizer on a monochrome LCD display equipped with an LED or EL backlight is that the backlight will be brighter. The disadvantage of the transmissive polarizer is that you can only read the LCD module when the backlight is “ON”. The advantage of the Transflective polarizer on a LCD display module is that you will be able to read the LCD module with the backlight “OFF”, but the backlight will not be as bright. The photos below are of a custom LCD module with these characteristics: TN, positive mode with a white LED backlight. The display on the Left is transmissive. The display on the right is Transflective.    Transmissive                   Transflective

• Chip On

  • The controller driver chip is mounted to the back of the LCD’s PCB.The controller/driver allows the LCD to convert the customer’s firmware/software into characters/graphics.
  • The mounting hole is where the customer uses a screw, or some type of mounting hardware, to connect the LCD to their product.

    The mounting hole has copper around the outside of the hole. Most of the time this copper is connected to the LCD ground. If you need to mount the display to your product without connecting to the ground, you have two options.

    1. Use a non-conductive mounting hardware. (such as plastic or equivalent)

    2. Have us modify the PCB to remove the copper from around the mounting holes.

    ØPlease, do not drill out the mounting holes, this will damage the PCB and cut the traces.

    
  • COG stands for Chip on Glass. There are many different types of displays. COB (Chip on Board), COF (Chip on Flex), TAB (Tape automated bonding) and COG. This is an LCD technology where the controller chip used to drive the LCD is mounted directly onto the LCD glass. Mounting the controller directly onto the LCD glass allows the module to be built without the need for a PCB. The three main components of a chip on glass is the glass, the controller driver chip, and the cable. As a general rule the cost of a COG is less than that of a COB. Without being mounted to a circuit board, COG displays do not come equipped with mounting holes. Instead the COG display is mounted to the chassis if the manufacturer’s product uses double-sided tape.

• Connection Type

  • Elastomeric connectors are rubberized layers of conductive and insulating materials. They are used to connect liquid crystal displays to circuit boards. Elastomeric connectors have benefits over your typical pin type connectors in that they are easier to install than the pin connectors and can protect the LCD against damage from shock and vibration in many products. Plus they can create a gasket-like seal for harsh environments.You can order them with insulators on both sides or with no side insulators. There are many different styles to choose from and some units can be made thinner than others. It’s best to check with the connector manufacturer as they will be able to direct you to the proper connector for your application.
  • We have found that when customers are using a display from another manufacture that has 14 pins and we send them a sample of an exact cross, they find that our displays have 16 pins. There is no difference between the two displays other than the 2 additional pins. Most displays come with three backlight options. Option 1: LED Option 2: EL Option 3: No backlightOn the PCB, pins 15 and 16 are used to power up the LED or EL backlight. I do not have a backlight: If you do not use a backlight, there is no need for pins 15 and 16. Some manufactures use a PCB with 14 pins on the displays that have no backlight and 16 pins on displays that have a backlight. This means they carry two different types of PCBs in stock. We find that it lowers the manufacturing cost to manufacture one PCB that has 16 pins. If you do not have a backlight, then pins 15 and 16 are not connected. They are just two holes that were drilled out of the PCB.I have an LED backlight: If you have an LED backlight, then you need to draw your power from some other location than pins 15 and 16. You have two options. Option 1: You can draw this power from pins 1 and 2. Note, this is only possible if your LCD voltage is the same as your LED backlight voltage. Some customers may have a 3.3V LCD and a 5V LED. If this is the case, do not draw the LED power from pins 1 and 2. Option 2: You can draw the power from pins A and K on the side of the PCB. I have an EL backlight: If you have an EL backlight, then you will have to draw the power from the A and K on the side of the PCB.
  • A trace, sometimes referred to as a track, is a strip of copper that runs from one connection on the PCB to another connection. The trace is used to carry the voltage/current from one area of the PCB to another. Many PCB’s have more than one layer. This is referred to as a multilayer board. If the PCB has more than two layers, some of these layers will be placed between the top and bottom layer. Making it difficult or impossible to see the trace. Note, cutting a trace is equivalent to cutting a wire. This will disrupt the flow of voltage/current from one area of the PCB to another.

• Controller

  • NO. Not all LCD controller/drivers are created equal. Focus Character LCD displays and Graphic LCD modules include built in controller drivers. The function of the controller driver is to convert the customers’ firmware/software to characters and graphics. Every few years the IC manufacturers discontinue their version of the driver and this forces the customer to switch controllers or rewrite their firmware. Many LCD display data sheets call out a specific controller/driver and then add the words ‘or equivalent’. Equivalent does not always mean 100% equivalent. There are small differences between each manufacturer of controller/drivers. We find that 95% of customers can switch from one controller to another with no hiccups, but there is 5% that do have issues. When we work with a customer on a new LCD project, regardless if this is a standard display or a customized LCD display, we suggest the following:

    • Ask if the current controller is being discontinued.
    • Test a sample of the controller/driver before ordering production quantities.
    • Think about whether you need additional displays for your repairs. You may want a last time buy of your current controller.

    Focus Displays designs and supplies custom LCD displays and can help you with your replacement LCD display needs.
  • This is code located inside the controller driver chip. This allows the customer to display which characters they want to display on the LCD module by selecting a memory location. This saves the end user much time by not having to program each segment (dot). Below is an example of a character generator for the English language. Note: There are character maps for many languages.
  • Character and Graphic LCD’s are supplied with an on-board Controller Driver (C/D). This is sometimes referred to as an IC (Integrated Circuit). There are different manufactures of controller drivers such as Sitronix, Epson and Sunplus. The Controller/Driver has the following functions: RAM This is the memory that is built into the controller driver that drives the LCD Module. Also called on-board memory Character Generator This is a library that converts the customer’s data to letter, numbers and punctuation marks. This is built into the C/D. The character generator is different for each language. Segment Driver The same chip that contains the controller can also drive the segments located on the LCD. If you need to drive additional segments beyond the capability of the Controller/Driver chip, you can add an additional driver chip. Each LCD requires only one Controller/Driver chip. Depending on the number of segments that need to be driven (aka displays) additional driver chips may be required. The black circular area on the back of the displays and pictured below, is the area where the controller is housed on the display.
  • The Serial Peripheral Interface or SPI-bus is a simple 4-wire serial communications interface used by many microprocessor/microcontroller peripheral chips that enables the controllers and peripheral devices(Such as an LCD Display) to communicate too each other. Even though it is developed primarily for the communication between host processor and peripherals, a connection of two processors via SPI is also possible. The SPI bus, which operates at full duplex (means, signals carrying data can go in both directions simultaneously), is a synchronous(occurring at the same time; simultaneous.) type data link setup with a Master(processor/Pic) / Slave(LCD controller) interface. The SPI Bus is usually used only on the PCB.The SPI Bus was designed to transfer data between various IC chips on the same PCB at very high speeds. Due to this high-speed aspect, the bus lines(The wires/traces or connections) cannot be too long, because the signal becomes unstable at longer distances . However, it’s possible to use the SPI Bus outside the PCB at low speeds, but this is not practical. An SPI protocol specifies 4 signal wires: 1. Master Out Slave In (MOSI) — This is the signal that is created by the master (aka processor) and is sent to the peripheral(s). 2. Master In Slave Out (MISO) — Slave (peripheral such as a LCD controller) generates MISO signals and sends them back to the Master (Processor) 3. Serial Clock (SCLK or SCK) – SCLK signal is generated by the Master to synchronize data transfers between the master and the slave. The goal is to have both processor and display set at the same time. 4. Slave Select (SS) from Master to Chip Select (CS) of slave – SS signal is generated by Master. This selects which peripheral is receiving the signal from the processor. There can be multiple peripherals connected to one processor. There may be other naming conventions such as Serial Data In [SDI] in place of MOSI and Serial Data Out [SDO] for MISO.
  • Your processor will not support an 8 bit or 4 bit parallel interface for your alphanumeric display. You are left with the option of a serial interface or SPI interface. In the past, serial was not a desirable option. Why?

    • The serial interface LCD module required additional electronics that increased the cost of a 16×2 LCD display or 20×2 LCD Display by as much as $10 per LCD.
    • The lead time of the Character display was longer.
    • The MOQ on the Character LCD module was high.

    This changes everything: Times have changed. Monochrome LCD displays are now available with the Sitronix ST7070. The cost difference: Much less cost than the $10 per LCD display in the past. The cost increase is about the same as upgrading your LCD module from a TN to a FSTN. Is there a tooling (NRE) fee? Smaller Character displays such as an 8 line by 2 rows, or an 8 line by 1 row may require a modified PCB to accept the new controller IC. The tooling cost is less than a custom LCD module that requires a bezel to be modified. Focus Display Solutions offers the character module with the serial interface. Whether you need a 16×2, 16×1, 8×2 or 8×1 LCD module, we offer our LCD modules with the Sitronix IC.

• Custom

  • The standard current draw of a static LCD module at normal operating temperature is between 1.2uA/square cm to 1.5uA per square cm. The required current is higher for a wide temperature LCD module. This does not include the power required for a LED backlight or EL backlight. In most cases, when a customer is looking for a ultra low power LCD display, they use a segmented module only. This glass only solution includes a static display or a multiplex custom LCD design. Focus display LCD’s have the following options:

    • 3V LCD driving voltage of 5V LCD driving voltage.
    • Normal temperature or wide operating temperature
    • TN, STN or FSTN
    • Parallel interface and SPI interface
  • EBT is the acronym for “Excellent Black Technology” LCD module. Sometimes this is referred to as a Jet Black Display. EBT displays provide a very dark black background. The contrast of this display is much sharper than that of a FSTN monochrome module. At this time all EBT LCD modules are custom and require a low Tooling fee and low MOQ compared to that of a TFT color module. Although the EBT display does not provide the multiple colors of a TFT or Field Sequential Color LCD Display, it does provide a sharp contrast ratio to exceed 200:1. The EBT Display can also provide a variety of character and icon colors at little to no extra development cost. Contact Focus Displays at 800-995-1825 for design assistance on your custom LCD requirements.
  • Focus Display’s Process for Custom LCDs
  • When a customer invests in tooling with the payment of an NRE (non-recurring expense), they are not just paying for the option to buy a customized LCD display, they are investing in a LCD design of their own. A customized display that matches the customer’s requirements exactly – everything from form fit and functions down to the module colors, unique voltages, addition of headers and any other desired components (resistors, potentiometers, etc.) to make this a modified LCD module. One of the most important, yet overlooked, values that come with a custom LCD screen is longevity. Investing in a custom LCD module can provide peace of mind. There are no more worries of having an LCD discontinued in the middle of the products lifespan, leaving a customer empty-handed with immediate requirements. Custom display orders do tend to have a slightly higher MOQ than standard LCD’s modules. This is because the product is only being sold to one customer so each batch will need to be consumed entirely by this customer. A common solution to the MOQ’s of a custom LCD is the placement of a blanket order with kan ban releases. Aside from the tooling fee and MOQ there are virtually no differences between orders of custom displays and standard displays. Lead times have no increases and the unit cost is no higher than its relevance to other similar products. Focus Displays is a custom LCD display Solution Provider. We specialize in Character LCD modules, Static LCD displays, mono dot matrix Graphic LCD modules and Custom Color LCD displays.
  • Focus Display Solutions specializes in LCD Modules and Glass Products including TN, STN, and FSTN display modes. In the last 12 years we have received many questions concerning the design and manufacturing of LCD modules, alphanumeric and graphic LCD displays. Below is a list of five common questions. Q1: What is the MOQ (minimum order quantity) of a custom LCD module? A1: There are three types of displays when you are engineering a Custom LCD. Character/ Alphanumeric LCD Displays: 1. These displays come as 16×2 LCD display, 16×1 LCD display, 20×2 LCD display and other options. The MOQ can be as low as 200 LCD modules. Graphic LCD modules: 2. These displays come as 128×64, 122×32, 320 x 240 and other options. The MOQ on these displays can be as low as 1,000 modules per shipment. There are exceptions to this if the only modification is a bezel or PCB. Static/Segment/Glass display: 3. These displays come as 7 segments and 14 segments with custom icons. The MOQ on these display modules is 1,000 LCD’s per shipment. Q2: Who owns the design and the custom tooling? A2: The customer invests the funds for tooling and engineering support. Therefore the design belongs to the customer. We will not sell a custom LCD solution to any customer except the customer that paid for the NRE. Q3: What is the current lead time? A3: The standard lead time for sample LCD displays is 5 to 7 weeks. The standard lead time for production quantities of your custom LCD module is 6 to 8 weeks. It may be possible to rush an order. We ship all our displays via air and not boat. Q4: How many samples of the LCD glass module will be supplied at no cost? A4: We supply five Custom LCD samples at no cost; the customer is able to purchase additional custom display samples at minimal cost. Q5: Does the tooling fee include the cost to ship the samples? A5: Yes, we pay the freight cost to expedite your samples. We then ship on your UPS/FED account from our location in Arizona to you. If you have a need for a unique display tailored to your application please contact us.

• Modifications

  • IDC stands for Insulation Displacement Connector. Below is a photo of a 2×7 pin header. This is called a 2×7 because there are 2 rows of 7 pins. Headers can come in many other combinations such as 1×3, 2×10 etc. The job of the pin header is to connect the LCD module to the customer’s PCB (Printed Circuit Board). This can be done in one of two ways. 1. Solder the header directly to the customer’s PCB 2. Connect the LCD module to the customers PCB with an IDC cable. Below is a photo of the IDC connector. Spacing: The standard spacing on a header is .1 inch or 2.54mm. This is called pitch. Pitch is the distance between each pin.
  • The jumpers on the back of a COB character LCD displays and COB dot matrix LCD modules have two primary functions. 1. Adjust the brightness of the LED backlight. 2. Adjust the LCD module contrast Many times the PCB contains jumper settings that allow this adjustment. If this is the case, then there is no tooling required and this is not considered to be a customized display, just a modified LCD. When the COB display does not contain a jumper, then the PCB needs to be redesigned. This will require a new LCD design. We would consider this to be a semi-custom or customized LCD to redesign the PCB , this would require tooling fees. Contact Focus Displays with any questions you may have. We can support your engineering requirements needs from initial prototype through final production.
  • The notes below are recommended for monochrome LCDs: Contrast is the ratio of the LCD segments that are “ON” and the LCD segments that are “OFF”. The goal is to have the greatest visible difference between the “ON” LCD module segments and the “OFF” LCD module segments. This can all be referred to as the ‘sharpness’ of the Liquid Crystal display. The same LCD will not behave the same on two different products. One customer may install a standard LCD module and have a sharp image. Another customer may install the same LCD and find the display is not clear. One solution is to modify the resistor value that controls the contrast of the monochrome LCD. By increasing or decreasing the resistance value of the resistor. If you find that the contrast is not as sharp as you like, please contact us to identify which resistor on your LCD display module will modify the contrast. When you locate the correct resistor, remove the resistor and replace it with a potentiometer (we recommend a 10K ohm value). Adjust the potentiometer until you arrive at the sharpness you desire. Notify Focus Displays of the correct contrast resistor value and we will modify the resistor on all future displays. Contrast can be affected by other variables such as TN display, STN display, FSTN display, normal temperature range or wide temperature range. Contrast is not affected by LED backlight, EL backlight of the type of polarizer such as Reflective polarizer, Transflective polarizer and Transmissive polarizer. The three types of displays and how to adjust the contrast is listed below: Alphanumeric LCD display / character LCD module / numeric LCD displays: The majority of our LCD display modules contain a resistor that allows the contrast to be adjusted. There are a few monochrome LCD’s that may need to have the Printed circuit board modified to accept the contrast resistor. Customers may also have the ability to adjust the contrast through their software or firmware. This includes the following models: 8 x 1 LCD Display module, 8 x 2 LCD module, 16 x 1 LCD Display, 16 x 2 LCD Display, 16 x 4 LCD Display, 20 x 2 LCD Display, 20 x 4 LCD Display, 24 x 2 LCD Display, 40 x 1 LCD Display, 40 x 2 LCD Display, 40 x 4 LCD Display Static LCD Segment Displays – 7(seven) segment, 14(fourteen) segment, 16(sixteen) segment displays: This type of display does not contain any resistors or a printed circuit board. The contrast adjust must be done on the customers board. Monochrome Graphic LCD Displays Many of these displays also contain a resistor to adjust the contrast. Customers may also have the ability to adjust the contrast through their software or firmware. This includes the following models: 122 x 32 graphic LCD display, 128 x 128 graphic LCD display, 128 x 64 graphic LCD display, 240 x 64 graphic LCD display. Many custom LCD displays may have the contrast resistor added at no additional cost.

• Polarizers

  • Let’s take a look at the technology behind LCD displays, and the basics of how they work. LCD – or Liquid Crystal Display is the technology that uses the special properties of liquid crystals to create products including televisions, monitors, clocks, and control panels. It’s often used as a broad umbrella category to cover other image technologies including cathode ray tube (CRT), Plasma and Light Emitting Diode (LED), which can be used in similar applications. However, those technologies operate differently, and for this article we’ll focus only on the function of LCDs. This includes a look at the basics of how LCDs work, specifically monochrome LCDs, as well as a more in-depth review of the two modes of LCD function: positive mode and negative mode. How LCD Displays Work: A High-Tech Venetian Blind An LCD works as a valve, either allowing light to pass through, or blocking it. Unlike some other image technologies, it does not generate the light itself. To help explain this, let’s compare the LCD to a venetian blind. As you know, you can adjust the blinds to alter the amount of light desired. When fully closed, the blinds block light completely; when open, all light passes through; and when angled, partial light comes in. An LCD works similarly to this, with one significant enhancement: an LCD has the ability to block light in some areas and allow light to pass in other locations of the glass. One significant advantage of LCDs over other technologies such as LEDs and OLEDs (organic light emitting diodes) is their power-efficiency. Because LCDs are not an emissive display technology – they control the light passing through them rather than producing the light themselves – they require less power to operate. Ultimately, that results in lower cost. LCDs can be designed in two ways, multiplexed or static. In a multiplexed approach, components of the display – segments or dots — are ON between 20% and 80% of the time, in an alternating system. In a static display, all segments are on 100% of the time. The result of a static display is a darker, more defined look. However, the tradeoff is cost. A static display is more expensive to run since resources are committed to each segment 100% of the time. How LDC Displays Work: Positive Mode – Letting the Light Shine Positive mode is the more commonly used of the two ways in which LCD displays work. In positive mode, dark letters, numbers, and symbols appear on a light background. Positive mode LCDs are popular because they don’t require a backlight to function, and therefore use less power. Typical applications of positive mode LCDs include wrist watches, hand-held calculators and battery-operated temperature gauges. How LCD Displays Work: Negative Mode LCDs – The Blackout Negative mode LCDs work in reverse of positive mode LCDs. In negative mode the characters are brighter than the background. Many users prefer to read from a negative mode LCD because the information stands out better from the background than in positive mode. However, though they are attractive and usable, negative mode LCDs have two drawbacks to consider: • The backlight must be on all the time to read the display. This increases power demand. • Hot spots are common in some negative mode displays. A hot spot is where there is a bright area close to the LED backlight and dark area, or cold spot, further away from the backlight. Products that typically use negative mode LCDs include cell phones, GPS, credit card readers, and appliances such as microwaves and coffee makers. How LCD Displays Work: Bringing it all Together LCD technology works in several modes to be both cost and design-effective in a range of applications. By either creating letters by blocking the light emission, or using a backlight to let bright letters shine through a dark display, LCD technology is implemented in both everyday consumer products and high tech applications.
  • 
  • Reflective-This is the standard polarize when there is no backlight. This is basically a mirror. The light comes in from the front and bounces off the mirror in the back. There is no backlight from behind, but edge lighting can be used. A backlight mounted behind the polarizer, will not work on this type of application. It will work just like a flashlight behind a mirror. The light will be blocked and not shine through. This is used where there is high ambient light and no need for a backlight, such as outdoors with strong sunlight or in a well lit factory. Tranflective- This is kind of a two-way mirror. The light comes in from the front and a backlight placed behind it will shine through. This is used in all types of lighting conditions. This makes it possible to read the LCD with the backlight on and with the backlight off. This is the most common polarizer for any backlight. If the customer is not sure what they want, and they have a backlight choose a transflective. Transmissive- This is where there will not be enough ambient light to see the display and needs a backlight on all the time. The transmissive polarizer makes the backlight brighter when the backlight is on. The LCD is difficult to read when the backlight is off. But it is still possible to read the characters.
  • A polarizer allows some light to pass through the liquid crystal display and some light to be reflected back towards the user of the display. There are three types of polarizer’s used in LCD display modules. These include character LCD module (or alphanumeric LCD display), Segment Display (or static display) and graphic LCD displays. Reflective mode LCD In the reflective mode, ambient light (the light that is available from the sun, office lights, etc) is used to illuminate the display. A reflective LCD module works the same as a mirror. It will reflect all the light it cast on it, but it will block any light that is placed behind it. It is possible to use a reflective polarizer with a side lit display. Advantages: The contrast is sharper then transflective LCD displays and transmissive LCD modules. Disadvantages: It is not possible to use a backlight behind the display. This type of display is best used where light will always be available. Transflective mode LCD A Transflective polarizer is a combination of both a reflective polarizer (no light may pass through) and a Transmissive polarizer (all the light can pass through). The Transflective mode LCD allows the user to read the display when the backlight is off. When necessary a backlight placed behind the polarizer can be turned on. This allows the user to read the display when in a dark location or ambient light is very dim. Advantages: The LCD can be used with or without the backlight being on. Disadvantages: The contrast is not as sharp as a reflective display. Transmissive mode LCD A Transmissive polarizer allows all light to pass through the display. The backlight must be on for the user to read the display. Advantages: The backlight will be brighter in a Transmissive LCD display than in a Transflective LCD module. Disadvantages: The display is very difficult to read when the backlight is not on. Summary: There is no difference in cost or lead time between Reflective, Transflective and Transmissive. It is possible to build any of the three polarizer’s as a TN display, STN display or FSTN display. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Segment Display module (aka: static LCD displays, seven segment display, glass only LCD display) The majority of segment displays listed below are TN, but they can be ordered in STN 7(seven) segment LCD display, 14(fourteen) segment LCD display, 16(sixteen) segment LCD displays, multiplex, mux, common mode LCD. Character LCD module (aka: alphanumeric LCD display, character LCD, numeric LCD displays) The majority of character LCD modules listed below are STN 8 x 1 LCD Display, 8 x 2 LCD Display, 16 x 1 LCD Display, 16 x 2 LCD Display, 16 x 4 LCD Display, 20 x 2 LCD Display, 20 x 4 LCD Display, 24 x 2 LCD Display, 40 x 1 LCD Display, 40 x 2 LCD Display, 40 x 4 LCD Display. Graphic LCD displays (aka Monochrome Graphic LCD Displays, dot matrix LCD module) The majority of Graphic Displays listed below are FSTN, but can be order in STN 122 x 32 graphic LCD display, 128 x 128 graphic LCD display, 128 x 64 graphic LCD display, 240 x 64 graphic LCD display Custom LCD displays can be ordered as TN, STN and FSTN. Also, LED backlight, EL backlight, but no longer available in CCFL backlight.

• Segments

  • This is a condition where OFF pixels, dots or segments are partially activated, producing faint images. The segments or letters that should not be “on” are a light gray. See the example below: ON OFF (ghosting)

• Temperature Range

  • When an LCD gets too cold the segments of the LCD become less visible and the response time of the display slows. Though short periods of exposure to temperatures below an LCD’s threshold only have minor effects on the LCD, prolonged exposure to the low temperatures will cause the liquid crystals to assume a solid state or crystallize(freeze). This is referred to as the Theoretical Crystalline-To-Nematic Transition Temperature. However, the low temperature effects are reversible. Even Liquid Crystal Displays that have been immersed in liquid nitrogen have been known to return to their normal operation after warming up. See graph below to see how rate of change of the LCD slows down as the temperature decreases.
  • Liquid crystal displays are just like their name… they contain a liquid between two layers of glass. Liquids begin to freeze as the temperature drops. As the display freezes their response time slows down. In other words, it takes longer for the numbers and letters on the display to change (Turn ON or Turn OFF). Above is a graph showing the response time of a display at -30°C (-22°F). The best way I can think to explain this is a ceiling fan. When you turn off the ceiling fan the blades continue to turn for a few minutes, even though the power if OFF. When you turn ON a ceiling fan the blades will be at full speed in a shorter period of time. At most the blades will be at their max speed within 30 seconds. When talking about an LCD, we talk about when the display is ON (the characters can be seen) or OFF (the characters cannot be seen). On the graph above there are two measurements. The left side is how dark the letters are; the larger the number the darker the letter. Along the bottom of the graph is the amount of time it takes to go from ON to OFF, or to go from OFF to ON. (Note: 1000mS is the same as 1 second). Line ‘A’ displays the amount of time it takes for a character or segment on the display to turn OFF. That is, once you turn OFF the segment, how long does it take before it disappears? The graph above shows that the character actually ‘disappears’ 3500 milliseconds (3.5 seconds) after the display is turned OFF. Line ‘B’ displays the amount of time it takes for the character or segment to turn ON. In the above graph the segment is only 55% ‘ON’ at 8000 milliseconds (8 seconds). That means the character is only ½ (half) ON. It will look grey and not very dark. It requires more time for the display to turn ON than to turn OFF… just the opposite of a ceiling fan. We do not recommend operating our wide temperature (extended temperature) displays below -20°C (-4°F). This is true for all segment displays (static displays or glass displays), 7 (seven) segment, 14 (fourteen) segment and 16 (sixteen) segment LCD’s. Alphanumeric LCD displays such as: 8×1 LCD Display, 8×2 LCD Display, 16×1 LCD Display, 16×2 LCD Display, 16×4 LCD Display, 20×2 LCD Display, 20×4 LCD Display, 24×2 LCD Display, 40×1 LCD Display, 40×2 LCD Display, 40×4 LCD Display will react the same way.

• Fluid Types of LCDs

  • FSTN is considered a better fluid technology than TN or STN. FSTN allows for a better viewing angle and better contrast. There is a higher cost for FSTN. TN was one of the first fluid technologies incorporated in LCD technology. The viewing angle is not as wide as STN or FSTN. Examples of TN LCD’s can be seen in pagers and gas pumps.
  • QVGA basically means a screen displays 320 x 240 pixels (or 240 x 320 if the display is taller than it is wide).This is one quarter of a VGA display (Video Graphics Display).
  • With LCD’s there are many different fluid types. The most common being TN, STN and FSTN. The LCD fluid twists the orientation of light passing through the glass causing the active pixels to darken. Each fluid results in different color, viewing angle, clarity and/or temperature range. TN (twisted nematic)is the most common fluid used in static and multiplexed displays. The TN technology comes in one coloration – black characters on a gray background. It is the least expensive and has the lowest visual quality, primarily in viewing angle. TN also has the best response time of the fluid types. HTN (high twisted nematic)has a contrast and viewing angle close to that of an STN display. The HTN fluid can be used with very low operating voltages and is only slightly more expensive than the TN fluid type. This makes it a popular technology in handheld applications. STN (super twisted nematic)is the most common fluid among monochrome LCD’s. STN comes in two colorations – dark blue characters on a gray background and dark gray/black characters on a yellow/green background. This is a middle priced fluid type with very good visual quality and contrast similar to the TN. The response time of an STN display is moderate. FSTN (film compensated super twisted nematic) is the most recent advance to be introduced. FSTN uses STN fluid with the addition of a compensating film which attains a higher contrast and larger viewing angle. The higher contrast supplied by an FSTN allows for a black and white display effect which also makes it the most expensive fluid type.
  • FSTN (Film compensated Super Twisted Nematic) FSTN monochrome LCD displays contains a retardation film applied to the STN display to produce a black and white display. This produces a higher contrast and wider viewing angle than STN or TN. Note: • Basic color options are black/white and blue/white • FSTN is the most expensive of the three options STN (Super Twisted Nematic) STN monochrome LCDs require less power and are less expensive to manufacture than TFT’s. They produce a sharper contrast then TN but less sharp then FSTN. Basic color options are Gray, Blue and Yellow/Green (most common). Other colors are available through the use of filters. Note: • Basic color options are Gray, Blue and Yellow/Green • STN are the most popular option today. TN (Twisted Nematic) TN monochrome LCDs are the lowest cost of the three options. The contrast is not as sharp as STN and FSTN. Primary color options are black letters on a gray background. Other colors are available through the use of filters. Note: • Basic color options are black letters on a grey background • TN has a faster response time than STN. Character LCD module (aka alphanumeric LCD display, character LCD, numeric LCD displays) The majority of character LCD modules listed below are STN 8×1 LCD Display, 8×2 LCD Display, 16×1 LCD Display, 16×2 LCD Display, 16×4 LCD Display, 20×2 LCD Display, 20×4 LCD Display, 24×2 LCD Display, 40×1 LCD Display, 40×2 LCD Display, 40×4 LCD Display. Segment Display (aka static LCD displays, seven segment display, glass only LCD display) The majority of segment displays listed below are TN, but can be ordered in STN 7(seven) segment LCD display, 14(fourteen) segment LCD display, 16(sixteen) segment LCD displays, multiplex, mux, common mode LCD. Graphic Displays (aka Monochrome Graphic LCD Displays, dot matrix LCD module) The majority of graphic displays listed below are FSTN, but can be order in STN 122×32 graphic LCD display, 128×128 graphic LCD display, 128×64 graphic LCD display, 240×64 graphic LCD display Custom displays Custom displays can be ordered as TN, STN and FSTN.

• Viewing Angle

  • You will see viewing angles for LCD’s described by 2 angles 6 o’clock(aka bottom view) and 12 o’clock (aka top view). This has nothing to do with time itself, but with what position you are in relation to the monitor (LCD)… the position being the center of the clock and viewer position represented by the corresponding clock face numeral position.You can get other angles such as 3 o’clock and 9 o’clock but these are special order!The majority of displays we sell are 6:00 view. These displays are best viewed when sitting or when standing with the LCD positioned even or above your head. (see photo below). There is no cost difference between bottom view and top view. Below is image showing the best viewing angle for a 6:00 display. The green area is the sharpest, Yellow next sharpest. The image below shows the viewing angle for a 12:00 (top view). The green area is the sharpest, Yellow next sharpest.

• Custom Color LCD Display

  • EBT LCD

    • Yes, it is possible to combine the two technologies. This is an option if you require the sharp contrast of an EBT LCD display with the color options of an FSC LCD module. It is important to note that EBT LCD displays has also been called Jet Black LCD displays. This display would be built to meet your dimensions and characteristics. Focus Display LCD’s could provide you with a data sheet and technical information before you order your samples. Lead time for tooling of this custom color LCD is currently set at 6 to 7 weeks. This would include prototype LCD samples for your product. Production quantities of your customized color LCD is currently at 6 to 7 weeks.
    • COB (chip on Board) is the current bonding technology at this time.
    • Yes. Many colors can be selected through the use of a RGB backlight.
    • >300:1
    • -30C to +90C
    • 80°/80° Left and right (X direction) 30°/80° Up and Down (Y direction)
    • EBT is the acronym for “Excellent Black Technology” LCD module. Sometimes this is referred to as a Jet Black Display. Example of an EBT LCD. EBT displays provide a very dark black background. The contrast of this display is much sharper than that of a FSTN monochrome module. At this time all EBT LCD modules are custom and require a low Tooling fee and a low MOQ compared to that of a TFT color module. Although the EBT display does not provide the multiple colors of a TFT or Field Sequential Color LCD Display, it does provide a sharp contrast ratio to exceed 200:1. The EBT Display can also provide a variety of character and icon colors at little to no extra development cost. Contact Focus Displays at 800-995-1825 for design assistance on your custom LCD requirements.

  • FSC LCD

    • The FSC LCD is a new custom color lcd display module technology that allows the customer to design a color display to fit their exact size. FSC-LCD’s, aka Field Sequential Color LCD produce a sharp contrast and ultra-fast response time at a fraction of the tooling cost for a TFT. One downside to this technology is the need for a built in booster circuit. The purpose of this additional circuit is to provide the necessary voltage to drive this display. OEM’s in certain industries cannot have this circuit for safety reasons. Contact Focus LCD Displays for any questions on a custom FSC LCD display at 800-955-1824.
    • Field sequential color displays provide all seven colors in each display. You do not need to pre-order the color you need. The color of the display is changed through the customer’s software. That is one of the great advantages of an FS color LCD. Another advantage of the display is the increased contrast ratio. The contrast ratio of this customized LCD display is 2x that of a TFT. The FSC display is custom built according to the customer’s drawings. There is no need to design your product around an off the shelf display. You design the custom color module around your product. We do offer demo boards of the FSC display.
    • FSC is the acronym for “Field Sequential Color” LCD.
    • 60 to 100 MCD
    • Contrast ratios of the following technologies are listed below. • FSC LCD = 100:1 • CSTN = 55:1 • STN = 5:1
    • The display will be black and dark.
    • 500,000 hours
    • No, FSC LCD’s can operate between 2.7V to 6V.
    • Yes, the viewing angle can be adjusted by varying the LCD driving voltage V0.
    • 3 to 4 seconds.
    • 8 colors: Red, Green, Blue, Yellow, Cyan, Purple, Black and White.
    • The FSC LCD uses RGB backlights instead of a color filter.
    • Yes, the FSC LCD requires an estimated 25% to 50% of what is required for a LED display.
    • Yes, the estimated tooling cost for a FSC LCD is 5% to 10% that of a TFT.
    • The unit cost of a TFT is an estimated 3x that of a FSC LCD
    • Drive types are:• FSC LCD = Static • TFT = Active Matrix • STN = High duty cycle
    • Response time is listed below:• FSC LCD = 4ms • TFT = 40 ms • STN = 150 ms
    • The answer is YES- Download Here FSC Display stands for Field Sequential Color LCD Display. This new technology is a low cost alternate to TFT displays. It is important to note that each FSC display is unique to the customer. There is no ‘standard’ or off-the-shelf FSC LCD module. Each custom color display is built to the customer’s engineering design. If you are looking for a color display that is bright and at a lower cost than TFT technologies, then the Focus LCD display FSC module is for you. Advantages of the FSC module:

      • Lower tooling cost then a TFT
      • Black background or white background with 7 additional colors
      • Low MOQ’s
      • Higher contrast ratio then a STN or TFT

      For additional information about this new technology, please contact Focus Display LCD’s at 1-800-995-1824.
    • Field Sequential Color LCD’s, also called FSC is a newer technology that allows the customer to design a custom static display with 8 colors.Advantages of FSC color over 7 segments. • Lower power consumption then a LED segmented display. • FSC display can be customized to meet the customer’s data sheet. • Low MOQ of 1K to 2K customized LCD modules. • Sharper contrast than the CSTN color module. • Customer can change the color of the LCD segment through the use of firmware. • Ultra fast response time. For questions, please contact a Technical Design Specialists at Focus Displays.
    • Focus LCD now offers a low cost alternative to custom color LCD modules. In the past the cost to modify a CSTN or TFT was very high and required a very high MOQ. Now with the availability of FSC LCD the cost and lead time has dropped.FSC LCD aka as Field Sequential Color LCD: allows a user to customize a color segmented LCD module. The LCD module can display segments in any of 8 colors. These colors are White, Red, Green, Blue, Yellow, Cyan, Magenta, and Black. Advantages of this technology include. • The FSC LCD uses less power then a LED segment display. • Ultra-high contrast ratio (>300:1) • Produces colors with the use of a RGB LED backlight • Interface includes both SPI and Parallel. • MOQ’s can be as low as 2,000 displays. An overview of the tooling process can be found here. Contact us for quotes, prototype samples and tooling support.
    • Yes, in the past OEM customers were limited to CSTN, OLED and TFT color LCD modules. If the design engineer needed a customized color LCD display, they were required to pay a very high tooling fee.Focus Displays now offers a low cost Color LCD Display Module. We are a Custom LCD display solution provider for small color LCD displays up to a 7-inch color segment glass. Below are photos showing possible customized LCD displays. We offer cost effective value added solutions for your color display design requirements. Some advantage of this new technology includes: • A faster response time then TFT and STN displays. • A sharper contrast ratio then TFT and STN We are the design engineers’ source for LCD specs, samples, prototype & support! Call us at 800-995-1824.

  • Business

    • Our goal is to reduce our customer’s lead time! This has become more important now as lead times with factories are increasing. We find that one of the greatest timing savings is to ship all LCD modules via UPS Air.The advantages of shipping display via AIR are: • We can ship one box alone and not wait until an entire pallet is ready to ship. • We can track the package and know where it is at any time. • The lead time from factory to Focus Displays is from 5 to 7 days.We believe we are the only LCD supplier in the USA that ships all our displays via air express.Below are estimated lead times for standard and customized LCD modules: • Custom LCD samples = 4 weeks • Standard LCD modules = 3 week • Production of customized LCD modules = 6 to 8 weeks • Production of standard LCD displays = 6 to 8 weeks Please add on one week of delivery time from factory to our LCD warehouse in Arizona.
    • FOB is short for Free On Board or Freight On Board. In other words, who pays the freight from the factory to you? We offer three options:1. F.O.B. Origin: This term mean that the customer is responsible for the international and domestic shipping on the product from the origin location (China, Taiwan, or some other origination point) to their dock. 2. F.O.B Ship point: This means that the customer is responsible for the shipping from our (Focus) warehouse in Mesa, AZ to their dock. 3. F.O.B Destination: This means that Focus is responsible for all shipping costs from the manufacturer to the end customer’s dock.So what is the best option? At Focus Display Solutions we recommend option 2, FOB ship point. This allows the customer to ship from AZ to their location on either their UPS, FedEx account or on the Focus UPS account.
    • There seems to be a push on for smaller character LCD modules that operate at lower voltages such as 3.3V. The smallest character LCD module we carry is an 8 character x 2 line in a parallel interface display. This is our FDS8x2(36×30)XBC. Customers need to display dot matrix characters and not 7 segment numbers that are found on static displays. The challenge with the character display is that you need a controller and sometimes a controller driver plus an additional driver chip to drive all the characters. Sometimes the customer needs this as a SPI/serial interface LCD display. This may require a standard off-the-shelf display to be a semi-custom modified LCD module.Focus Displays is able to modify the LCD glass size of a display, the downside is that there will need to be a modified bezel. This could increase the tooling cost.Contact us for tooling cost and lead time on prototype samples of customized monochrome LCD’s.
    • Focus Display Solutions is a supplier of alphanumeric LCD modules to OEMs.The most popular character LCD display we offer is the 16×2, LED backlight, STN, wide temperature with yellow/green background. 5 Volt LCD logic and 5 Volt LED backlight. We are seeing the 3 volt LCD Logic and 3 volt LED backlight becoming more common. Our goal is to keep inventory/stock of these displays for samples to engineers. One of the main reasons this is so common is that the 16×2 alphanumeric display comes in 10 different sizes of COB. If you need to modify the mounting holes of your character display, this would become a semi-custom LCD module. Call us for same day support and quote on tooling. If you need a modified font on your LCD module, this would require a custom display. With a customized LCD modules, you would receive samples and support for the prototype.
    • We find that the 128×64 FSTN with LED backlight seems to be in the highest demand. We currently carry 8 different configurations of the 128 x64 pixels.All displays are available with both Transflective and transmissive polarizer options. The Mono Graphic LCD Module we carry in stock at all times is the FDS128x64(70×44). This has a Resolution of 128×64 Dots. The features of this Liquid Crystal Display are: • FSTN is the most common option for non-color monochrome displays • Positive mode • COG, the advantage of COG over COB is the lower unit cost • This display operates as both a parallel and serial (SPI) interfacePlease call us today for your new engineer design.
    • At Focus Display Solutions, we ship all our LCD display modules from the factory by UPS air. There are several reasons why we do this.

      • The LCD modules arrive from the factory in less than 7 days.
      • We can ship as few as one box if necessary. Many times when you ship by boat, you need to have a minimum number of boxes or weight before they will ship. This means that your liquid crystal display may be waiting for some time before it ships.
      • We are able to track and estimate within a day or two when your display modules will arrive.

      Of course, this brings up the question of cost. Do we charge more to ship by air instead of boat? The answer is yes. We could save you a few pennies per LCD display to ship by boat. However, the downside is that your lead-time would stretch from 8 weeks to 16 weeks or more. We find that most customers prefer not to have to order their LCD’s 3 to 4 months in advance. Current Lead times Each monochrome display has many options. The options below do not affect the lead-time of any Alphanumeric or Numeric LCD Display. • TN display, STN display or FSTN display • LED backlight or EL backlight • Normal temperature or wide temperature • Reflective, transflective or transmissive At the time of this writing the standard lead time for Focus Displays is listed below by type. Alphanumeric LCD display / character LCD module / numeric LCD displays are at 8 weeks. This includes the following models: 8×1 LCD display, 8×2 LCD display, 16×1 LCD display, 16×2 LCD display, 16×4 LCD display, 20×2 LCD display, 20×4 LCD display, 24×2 LCD display, 40×1 LCD display, 40×2 LCD display, 40×4 LCD display. Static LCD Segment Displays – 7(seven) segment, 14(fourteen) segment, 16(sixteen) segment displays are at 7 weeks. Monochrome Graphic LCD Displays are at 8 weeks. This includes the following models: 122×32 graphic LCD display, 128×128 graphic LCD display, 128×64 graphic LCD display, 240×64 graphic LCD display Replacement Monochrome LCD Modules / Custom LCD Display Design and Engineering may take up to 4 weeks additional lead-time.
    • The answer is YES- Warrany Policy