Before ordering an LCD to be integrated into a long-term project, there are several questions an engineer should ask. The most important question that needs to be asked is what the estimated long-term availability of the display is.
Long Term Availability
Will this display still be in production in two or four or six years?
This is a key question since you don't want a production line down when your guaranteed LCD is no longer available. You will be forced to locate another source, and chances are, the replacement display won't be a drop-in equivalent.
A different display means modifying some part of your design like your source code, mounting options, and the type of connection between your PCB and LCD. Finding replacement parts can easily eat up your time and resources.
The only display technologies with a very long production lifetime are character and custom segment displays. They have been around for many years and rarely change. Additionally, they are still popular on new designs.
But what about other display technologies?
Organic light emitting diodes can offer sharp contrast and use less power, but they are prone to obsolescence. Many OLED displays are be popular for a year or two before becoming obsolete. The reason for this is due to limited manufacturing capabilities. When usage of a specific display drops, the manufacturer will discontinue it in favor of a much more popular version.
Thin film transistors are similar to OLEDs in that they produce 64K unique colors, can display video and graphics, and are bright. TFTs tend to stay in production for years, so a four or five year lifetime is not that unheard of.
Character displays have been around for many years. The technology doesn't change, and they are still one of the most popular display options available. They are built in standard sizes and are available from several sources. Even if one supplier pulls the plug, others will offer a drop-in equivalent.
Most segment displays are custom to the customer. Tooling fees, or NRE, are low which is what makes segment displays so attractive to someone looking for a custom display. Once the tooling is completed, production is very simple and low cost. Segment display manufacturers rarely discontinue them since most segment displays have few components. A segment display has a basic build consisting of ITO glass, pins and a nematic fluid.
A Note About Discontinued Controllers:
Most LCD modules contain a controller that interfaces between the raw LCD and your processor. Hence, the word module means that it has some type of brain/controller attached to it. It is common for controllers to be phased out and replaced with an equivalent, but equivalent does not mean that your firmware will be 100% compatible. You may have to modify your code. Updating your code is not a big drain of time, but it makes it tricky to use new displays for warranty service on older products.
Not sure what is the best for your new OEM design? Contact Focus LCDs for support. We will help you answer key questions such as:
- What is the best display for low power?
- Will a multi-color display work?
- What type of touch screen is best?
- Will the display operate in the environment?
- Which is best for sunlight readability?
- Can this display video?
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