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Character LCD
Character LCD Display Modules
Character LCD Displays (aka Alphanumeric) are one of the most common display technologies available and for that reason we hold inventory for samples and prototypes in our Chandler, Arizona location.
If you require assistance or need to order an LCD now, just call us (480-503-4295) or contact us.
These displays have been in use for many years, and in some ways the technology has become a commodity, but it is important to select the best options to fit your design. There are many details concerning this technology, including: fluid type, operating voltage, controller/drivers and other key details that can make your design excel or under-perform.
Our team of LCD specialists can assist you in selecting the best options so that your design is able to meet your needs and at a cost that is within your budget. Call today with any questions.
A character is any letter (capital or non-capital), any number or punctuation mark (including a period, comma, back slash, etc.).
These displays are used in applications such as change machines, measurement devices, and data loggers. The module has the ability to display letters, numbers and punctuation marks.
Character LCD Displays Make Use of a Character Table
One reason for the popularity of Character LCD displays is that they are equipped with a controller/driver chip containing a built in character (or font) table.
The table holds preloaded letters, numbers, and punctuation for each language. The font table allows the designer to request any character by addressing (selecting) the number of that character. In other words, the letter capital ‘T’ may be assigned the number 31 and the “&” symbol could be assigned number 141. This eliminates the work required to create each charter from scratch and reduces the amount of time necessary to program the LCD module.
Our standard character displays incorporate an English font, but other languages are available upon request.
Options Available for a Character LCD
Negative mode and Positive mode.
Monochrome displays can be built as Negative or Positive mode depending on the appearance you want to achieve.
The LCD you choose for your new design sets the perceived value of your product. Think about it: The first thing your customer looks at when they are deciding whether to purchase your product, is the LCD display. If it looks good, then your product looks good.
Here are a few details to consider when choosing the mode for your monochrome character LCD.
Negative mode Vs. Positive mode.
Negative mode displays are popular for new designs since they stand out. Negative mode means the background is a darker color, like black or blue and the characters/icons/segments are a lighter color such as: White, Red or Green.
The opposite of a negative mode is positive mode where the background is a lighter color such as yellow/green or grey and the characters/icons/segments are a darker color like black or dark blue.
Negative mode displays must have a backlight on all the time to be readable. The challenge is that the LED backlight will draw/drain 10 times more power than the LCD without a backlight. So, if this is a battery application, it is best to stick with a positive mode.
Positive mode displays are readable without a backlight if there is enough ambient light. The LCD without a backlight will draw around 1uA. LED backlights can draw as little as 15mA up to 75mA or more depending on the number and brightness of the LEDs.
The LED backlight on a positive mode display can be turned on for it to be readable in the dark.
Positive mode displays are excellent for sun light readable.
Cost difference?
A negative mode LCD is the same cost as a positive mode containing a built in LED backlight.
Lead time difference:
There is no difference in lead time between Positive or Negative. We carry both versions in stock and in many cases can ship the same day.
There are several options available when ordering your character LCD. Below is an overview of choices available that do not require a tooling fee.
Size of the LCD
The first question to answer is ‘what size of LCD?’ The larger the display the more information that can be displayed and the larger the characters can be. We recommend you choose one of the standard sizes on this page to reduce cost and lead time. Focus Display Solutions (aka FocusLCDs) carries many of the industry standard sizes in inventory and may be able to ship the same day.
If you do require a unique sized display, contact us concerning a custom LCD option.
Number of Characters
Character LCD Displays are built in standard configurations such as 8×1, 20×2 and 40×4. The two numbers identify the number of characters in each row and then the number of rows. An example of this is a 20×2 which means there are 20 characters in each row and there are two rows. This will provide you a total of 40 characters. The more characters there are on the display, the more drivers are required to drive the LCD. The controller and drivers are included with the LCD.
Note: It is possible to program the software to scroll your letters and numbers across the screen, allowing you to choose a smaller sized LCD and still display all your information.
The cost of character displays is driven more by the size of the glass, then by the number of characters. A larger 8×1 can be more expensive than a small 16×2.
Listed below are the most common standard character configurations.
- 8×1; 8×2
- 16×1; 16×2; 16×4
- 20×1; 20×2; 20×4
- 24×2
- 40×1; 40×2; 40×4
It is possible to custom build a unique combination such as a 12×2 or a 16×8. This would be considered a custom LCD and would require a one-time tooling cost and possibly a higher MOQ. Go to our Custom LCD page for information.
Character LCD Operating Temperature
Character LCD modules are available in two temperature ranges, Normal (for indoor use) and Extended (for outdoor use). The outdoor version will continue to operate down to -30C. The cost difference between normal and wide (extended) temperature range is 5% to 7% higher for the extended versions. In most cases, if cost is not critical, we recommend that you incorporate the wider temperature version.
If the display is required to operate at temperatures below that, we can add a heater that will allow operation down to -50C.
Note: the addition of a heater will require additional power and in some cases a one-time tooling fee.
LCD Backlight Options for a Character Display
There are three types of backlights available for a character LCD module: No backlight; LED; or EL backlight. Before introducing the various backlight options, it is helpful to cover two terms that are common for backlights: NITs and half-life.
Backlight Nits – A NIT is the measure of the backlights brightness. One NIT is roughly equivalent to the amount of light produced by one candle.
Backlight Half-life - The half-life of a backlight is the amount of time, in hours, that the backlight will burn before it is half as bright as when it was first turned on. So if its rated half-life is 50K hours, then the backlight will be half as bright at 50K hours as when it was first turned on. The same backlight will be 25% as bright at 100K hours as when it was first turned on.
Half-life may not be critical for your application if your backlight is on for limited amounts of time.
There are three types of backlights available for a character LCD module:
- No backlight
- LED backlight
- EL backlight
Character LCD with “No backlight”
Engineers designing a battery powered product may request a character module with no backlight since the backlight draws more than ten times (10x) the power required for the LCD alone. The goal with a battery powered product is to conserve power and extend the life-time of the battery.
If the product needs to be readable in the dark or low light conditions, then it will be necessary to attach a backlight of one type or another. The best way to conserve power is to keep the amount of time the backlight is on to a minimum. Turn off the backlight as soon as the user no longer needs it. This is a common practice in cell phones. The backlight turns off a few seconds after the number is dialed or the phone is answered. The person using the phone will continue to talk, but the display will be dark.
Character Modules with “LED backlight”
LED (Light Emitting diode) backlights are the most popular backlight option for displays that need to be readable at night. Reasons include:
Half-life of LEDs - The half-life of a LED backlight can range from 50K hours to 90K hours depending on the amount of driving current, compared to the half-life of an EL backlight which averages 3K hours.
DC Current – LEDs are driven by DC (Direct Current), which is the same type of power required for the character LCD logic voltage. Also, batteries supply DC which makes it easy to integrate the LED backlight with a battery. EL backlights require an AC (Alternating Current) to operate. The AC signal needs to be generated by an inverter. The added inverter increases the cost of the display and produces electrical noise that can interfere with neighboring circuits.
Dimmable – LED backlights are easily dimmable; the user can adjust the brightness by reducing the driving current supplied to the LED. The ability to dim the backlight allows the user of your product to select different brightness levels. An example would of this might be a higher brightness while plugged into an outlet, and a dimmer brightness if battery driven. This is a common practice for cell phones. The backlight will be at full brightness for the first few seconds and then dimmed for the next few seconds. Note: Cell phones use OLED or TFT displays and not character technology.
Character Display with “EL backlight”
Character LCDs that include an EL (ElectroLuminescent) backlight are not as common and their popularity is decreasing. EL backlights are AC driven which requires an inverter to be supplied by the customer or attached to the LCD. Their half-life is rated at 3K hours which makes this a poor choice for products where the backlight will be on all the time. Their MOQ (Minimum Order Quantities) have increased in the last few years. At this time there is a 500 piece MOQ.
There are some key advantages to EL backlights. They are very thin, around one to two millimeters in thickness. And they provide a very even flow of light. We carry inventory on a few EL character displays, but the majority of the character displays we sell are LED.
Focus Display Solutions sells standard and non-standard LCDs with an EL backlight. Call today to speak to one of our LCD specialist.
Backlight color
There are several possible combinations of background colors. The most common color options are yellow/green; green/grey; blue/white; black/white; and RGB (Red/Green/Blue).
16×2 Character LCD, Transflective (works with or without the backlight),
Yellow/Green LED Backlight, STN bottom view (6:00), positive mode
16×2 Character LCD, Transflective (works with or without the backlight),
Amber Side-lit Backlight, FSTN, wide temp, bottom view (6:00), Positive mode
16×2 Character LCD, Transflective (works with or without the backlight),
Pure Green Side-lit Backlight, STN gray, bottom view (6:00), Positive mode
16×2 Character LCD , Transflective (works with or without the backlight),
White LED Side-lit Backlight, FSTN, bottom view (6:00), Positive mode
16×2 Character LCD, Transflective (works with or without the backlight),
White LED Side-lit Backlight, STN gray, bottom view (6:00), Positive mode
16×2 Character LCD, STN Blue Side-lit Backlight, bottom view (6:00), Negative mode
16×2 Character LCD, FSTN White LED Side-lit Backlight, bottom view (6:00), Negative mode
16×2 Character LCD, reflective, no backlight, STN yellow green, bottom view (6:00), Positive mode
TN, STN, FSTN Fluid types
Character LCD Displays are available in multiple different nematic fluid types, but the three most common are: TN; STN; and FSTN.
A character LCD is constructed by placing the nematic fluid between two layers of ITO (Indium tin oxide) glass. The function of the fluid is to either block or allow light to pass through.
TN fluid in character LCDs
A TN (Twisted Nematic) monochrome LCDs is the lowest cost option. TN does not provide a very sharp contrast and has a smaller viewing angle then STN or FSTN. A smaller viewing angle means the display is readable if you look directly at it, but if you rotate it more than 40 degrees in either direction, the characters will be difficult to read.
An advantage of TN is faster response time than STN and FSTN and its ability to operate at lower temperatures. We recommend this fluid for applications that will operate at extremely low temperatures.
TN is the lowest cost option of the three and is used primarily on segment types of displays in applications such as gas pumps and pagers. Below is a photo of a 20×4 character LCD with TN fluid.
TN
STN (Super Twisted Nematic)
STN (Super Twisted Nematic) fluid is the most popular option. It provides a sharper contrast and a wider viewing angle than TN. Below is a photo of a STN 16 x2 character display.
STN
FSTN (Film Compensated Super Twisted Nematic)
FSTN monochrome character LCD displays are assembled by taking the STN fluid and adding a film or retardation coating to the glass. This produces a sharper contrast than STN. FSTN is more popular on higher end products such as medical applications. Below is a photo of a FSTN 16×2 monochrome LCD
FSTN
The cost difference between TN to STN ranges from 5% to 10%. The cost difference between STN to FSTN ranges from 7% to 12%.
If you are unsure which fluid is best for your product, contact one of our technical LCD specialists to request details for your application.
Polarizer
There are three types of polarizers: Reflective; Transflective; and Transmissive. The correct polarizer is determined by the various lighting conditions your character LCD display will operate in.
Why does a LCD Display require a polarizer?
The job of the polarizer is to allow some light to pass through and some of the light to be reflected. Depending on where your display will be operating, will decide which polarizer to choose. There is no cost difference between the three polarizers. Below is a quick summary:
Reflective polarizer
The reflective polarizer is basically a mirror. It will reflect 100% of the ambient light and is ideal for displays operating in direct sunlight or in situations with very bright indoor lights.
A reflective polarizer cannot be used with a LED backlight or EL backlight since it will not allow any of the light to pass through, but it is possible to use with a LED edge-lit or side-lit display. An advantage of an edge-lit display is that it is thinner than a LED backlight, but not as thin as a display equipped with an EL backlight.
Transflective Polarizer
A Transflective polarizer is the most popular of the three options and works best with a display that requires the backlight to be on some of the time and off some of the time. It does not perform as well in direct sunlight as a reflective polarizer, but is sufficient in most cases.
If you are not sure which environment your display will operate in, choose Transflective.
Transmissive Polarizer
The Transmissive polarizer is used when the backlight is on all the time. This is not the best option for battery powered products, but provides a brighter backlight. This polarizer must be used for displays that run in negative mode. Negative mode is when the characters are light colored and the background is a dark.
Transmissive will provided the brightest backlight possible. If the same backlight is used on both a Transflective and a Transmissive. The brightness of the backlight on the Transmissive will be noticeably brighter.
For more detailed information on polarizers, check out: LCD polarizers: reflective; transflective; transmissive or call us.
Two types of LCD voltages VLCD and VLED:
Monochrome (non-color) displays contain two separate voltages.
V Logic is the voltage used to drive an LCD and draws very little current, somewhere around 1mA or less. Character displays can be driven with a VL at 3.3V or 5V.
V LED is the voltage used to drive the LED backlight only. This can be 3.3V or 5V. LED backlights can draw up to ten times (10X) the amount of current of just the LCD alone (VLCD). If your product is a battery application, the backlight should be turned off when not in use. Or build in a sensor that only turns it on in the dark.
LED backlights are DC (Direct Current), which means they need to be connected correctly. Positive to positive etc.
Is it possible to drive the LCD and the LED backlight from the same connection, but not recommended since interference from the LED backlight could affect the performance of the LCD.
Two Voltage Options
There are two standard logic voltages for the display. 5V (most common currently) and 3.3V (on its way to becoming the most common.)
There is no difference in price or lead time between the two.
3.3V is popular for battery applications since it can be driven by two ‘AA’ batteries. The downside is their performance suffers in colder temperatures and may require a heater to continue operation.
Choose a 5V if your product will operate in colder temperatures and you have unlimited power. In other words, if your product is plugged into a wall or car battery and there is no concern for battery drain.
Low Power
A key advantage of character LCDs over multicolor technology such as TFT (Thin Film Transistor) and OLED (Organic Light Emitting Diodes) it their low thirst for current.
TFTS and OLEDs require power to generate light to be readable. In many cases, their backlight needs to be even brighter in direct sunlight. This could draw 50mA or more depending on the size and brightness of the display.
Character LCDs draw less than 1mA when the backlight is off. A great option for battery powered and handheld products.
LCD Heaters
When the ambient temperature of the display drops too low, the display’s performance suffers. The colder the fluid in the display, the slower the response. At some point, the display freezes up and the characters no longer change.
As long as the temperature doesn’t drop too low, there will be no damage to the display, and it will return to normal operation when the temperature rises.
To deal with performance issues at low temperatures, there are several sources of heat that can help to keep the display functioning:
Heater film:
This is a transparent film that lays across the top layer of the ITO glass. It provides an even flow of heat and is the most effective heating solution. However, it is also the most expensive heating solution.
Resistors:
This is a much more affordable solution. A small PCB (Printed Circuit Board) is attached to the back of the LCD. The board is populated with several quarter watt resistors in series that generate heat. This option draws a great deal of power. In fact, it draws more than most LED backlights.
Not recommended for battery applications.
LED backlight:
Believe it or not, LEDs do generate heat, but nothing close to resistors or heater film. In some cases, it is enough to give the display a little extra warmth to keep it operating when the temperature drops below its threshold.
Insulation:
Nothing saves heat and power like insulation. Putting your LCD into something that breaks the wind and holds in the heat, will save your batteries. Many times, a protected display will continue to operate even when the temperature drops far below the threshold. This should always be the first step taken when worrying about display functionality at low temperatures. Once your product is insulated, the heat producing options noted above can be implemented.
Cold Start vs. Cooling Down:
Displays that are operating as the temperature drops, will continue to operate below the threshold, although their performance will suffer.
Displays that are switched from off to on while below the temperature threshold may not operate until the fluid inside the display is warm enough.
Best Fluid for Cold Temperatures:
There are three fluid types used in character LCDs: TN, STN and FSTN. TN operates the best at colder temperatures and offers a faster response time. TN does not provide the wide viewing range found in STN and FSTN, but is sufficient for most industrial uses.
Low Probability of Discontinuance:
The five most common types of LCD technology are: Segment, Character, Graphic, TFT and OLED. Character and Segment are the least likely options to be discontinued. They have been around for many years and are still very popular.
Character LCDs have been standardized for years. One supplier’s display will swap out for another suppliers.
No MOQs:
Character LCDs are kept in stock, there are no MOQs (Minimum Order Quantities) as are usually found with OLEDs and custom displays.
Dot Matrix:
The displays are made up of small squares that contain a 5x8, 7x10 or 16x16 dot matrix configurations. That means there are 5 dots across and 8 dots up for a total of 40 dots. Each dot is individuality addressed on or off to produce any letter or number.
The 7x10 produces a larger character to be seen at a distance.
The 16x16 is mainly used for Chinese characters since there is more detail
Pinout of a Character LCD
|
Pin Number |
Pin Name |
Pin Description/Function |
|
1 |
VSS = Ground |
Connect this to your system ground or reference |
|
2 |
Vdd (Logic power or LCD power) |
Logic voltage is used to drive the LCD. This could be 5V or 3.3V. 5V is best for colder temperatures |
|
3 |
VE |
Contrast adjust. Used to lighten or darken the character with respect to the background color. This is done by adjusting the voltage (through a potentiometer or software) between max logic voltage and ground |
|
4 |
RS = Register Select |
Connect this to your microprocessor to shrift between the Command and the Data register |
|
5 |
RW = Read/Write |
Used to read or write the data being transferred between the LCD and the microprocessor. Tie this to ground if you only plan to write data for one-way communications. |
|
6 |
Enable |
Enable or disable. Sends a 0 or 1 to communicate with the microprocessor |
|
7 |
DB0 |
DB 0. Most character LCDs have eight (8) data bits for faster transfer. But can operate on just four (4) data bits if you are running low on I/O (In/Outs) pins. |
|
8 |
DB1 |
Data bit 1 |
|
9 |
DB2 |
Data bit 2 |
|
10 |
DB3 |
Data bit 3 |
|
11 |
DB4 |
Data bit 4 |
|
12 |
DB5 |
Data bit 5 |
|
13 |
DB6 |
Data bit 6 |
|
14 |
DB7 |
Data bit 7 |
|
15 |
LED + |
Positive connection of the LED backlight or side lit. The voltage could range from 5V or 3.3V. Not all character LCDs contain a LED backlight. In this case, the two pins are no connect. |
|
16 |
LED - |
Polarity is an issue with LED backlights, since they are DC (Direct Current). That means positive must connect to positive. Half of the character LCDs have pin 15 as positive and 16 as ground. The other half are reversed. If you need the polarity reversed, there is a jumper on the back of the PCB to switch polarity. |
Character LCD for a new project
Focus Display Solutions works with many OEMs and design houses to design in character LCDs for new projects.
Character display falls into three categories:
- Standard off- the-shelf display
- Special order (a display with a unique color combination and driving voltage etc.)
- Custom character LCDs.
1. Standard Off-the-shelf character LCD
Focus Display Solutions stocks sample and production inventory in our Chandler, AZ warehouse or through distribution.
This page contains a partial list of our standard displays. Simply choose the number of characters, the size of the display and the color combination that will meet your needs. If you need a size not listed on this page, please call us. We can still supply it to you.
Our lead time on standard Character LCD displays – that are not in stock – range from five to seven weeks. This rapid lead time is due to the fact that we do not ship LCD’s via boat, but FedEx Air. By shipping via FedEx Air, we receive the LCD glass within four to five days after it is completed, compared to shipping by boat which can add several additional weeks to your lead time.
Questions? Feel free to contact our US based technical support team about character, or any other LCD technology.
2. Special Order Character LCD Modules
Don’t see the exact display you want on this page? Focus Display Solutions can supply you a display to match the exact configuration you want, even if it is not in our current inventory.
Available options include: background color, backlight type, operating temperature range, driving voltage and other possible choices. These are modifications that do not require a tooling fee.
Call one of our technical LCD specialists to assist you in selecting the best configuration to meet your requirements
3. Custom Character LCD
Focus Display Solutions is able to design and supply a custom character LCD solution to meet your requirements.
The cost to design and tool up a custom replacement LCD is much less than the cost associated with retooling a case or having to redesign the customer’s PCB to accept a different LCD. The customer may also need the exact display to repair units that are in the field.
Here is a case study on a custom 40×2 display that was redesigned to match the customer’s current product. Case Study.
This custom character design allows the customer to avoid any redesign cost or delays in the manufacturing of their product and to offer replacement displays for products that had been in the field for over ten years.
Character LCD as a Replacement Part
We receive many requests for LCDs to replace those manufactured by other LCD suppliers.
Character LCD displays are built in standard sizes and configurations. This makes the process of locating an equivalent LCD a simple process, but it is critical to make sure that the replacement display is a drop -in equivalent to your current display. It may not be possible to build a 100% equivalent product without some modifications.
Some LCD suppliers such as Seiko, Standish and Ocular (who no longer supply LCDs) had developed character LCDs that were unique. That is,they were not a standard off-the-shelf displays.
We are able to match and replace these discontinued Liquid Crystal Displays. There may be a one-time NRE (Non-Recurring Engineering) fee required to modify the ITO glass, PCB (Printed Circuit Board) and bezel to match the dimensions and characteristics necessary for your production.
If your current LCD supplier has discontinued your display, Focus Display Solutions (aka Focus LCDs) has the ability to cross it over to an equivalent display and in many cases Fed Ex/UPS a sample to you the same day.
Call one of our US-based Technical Support people at 480-503-4295 or email us by using the Contact form. We respond to all business inquiries within one business day and in many cases can offer you a quote the same day.
To begin the process of replacing your discontinued LCD, we will need one of the following:
- Current LCD part # of the display you were purchasing
- Data sheet of the display you were purchasing (This is the preferred option)
- Photos of the display
Note: when you begin ordering LCD displays from Focus, we will supply you with the data sheet. If you purchase the display, you should own the data sheet.
1. Current LCD Part #
Providing us the full part number of the LCD allows us to determine not only the size of the display, but also the type of construction such as COB (Chip on Board) or COG (Chip on Glass), number of characters, backlight option, operating temperature range, background and backlight colors, viewing angle, backlight and LCD logic voltage, and in most cases the controller driver used.
With the part number, we will attempt to locate a full data sheet with enough details allowing us to quote a replacement for your discontinued display. If we cannot locate a data sheet, we will ask if your previous supplier had provided one to you.
2. LCD Data sheet
If we are unable to locate the data sheet of your current LCD, we will request a data sheet. If possible, please forward over the data sheet or a link to the data sheet. If your LCD supplier is no longer in business or they will not provide you the data sheet, the next option is a photo of the display.
3. Photos of character LCD
If you are unable to locate the data sheet and we cannot gather enough information from the LCD part number, we can estimate a cost from a photo.
We require two photos to estimate a quote.
- The LCD next to a ruler or tape measure.
- This allows us to determine the dimensions of the LCD.
- A photo of the LCD when it is on, this can be a photo from your web page.
- This photo is necessary to determine if there is a backlight and the background color.
Send the photos to our contact us page.
If you decided to move forward with us and order samples of your replacement display based on the estimated cost, we will require two of your discontinued samples. They do not need to be working displays, but need to be in good condition. Please note: We will not be able to return the two displays.
Note: when you begin ordering LCD displays from Focus, we will supply you with the data sheet. If you purchase the display, you should own the data sheet.
Do you have any questions? Call now for support and lead time on samples.