Embedded designers must usually work to a strict power budget, and if early calculations prove to be on the optimistic side there can be pressure to cut back on some features to ensure the total power remains within the specified maximum. Simply increasing the amount of power available is rarely an option!
A colour TFT display can be a power-hungry part of any design. The resolution can usually be anywhere from 320x240 to full HD, and simply reducing the number of pixels that must be driven can help to trim the power consumption. One way to do this is to modify an off-the-shelf display. Another approach, which Anders can help with, is to create a custom TFT with lower pixel resolution in the size you require.
If larger power savings are needed, a monochrome xSTN display provide an effective solution. The nature of monochrome inherently has one-third fewer pixels, and resolution is typically slightly lower than a comparable TFT. A 128x64 STN display can deliver a good user experience. The power dissipated by the backlight can also be reduced, as there is no need for the intense backlighting often used to ensure strong colour rendition from a TFT. In addition, the bill of materials can be reduced, as less RAM is required. Several types of monochrome STN displays are available, including FSTN, FFSTN, DSTN and ASTN .
If you choose the monochrome route, a full custom display can be cost-effective. This gives the opportunity to include icons or graphics unique to your product, achieve colour effects by altering the backlight or using filters, or specify a custom size, or special assembly techniques such as heat-sealing to withstand harsh environments.
We have helped many product developers to design and source custom displays for their projects, realising significant power savings while at the same time achieving striking visual effects through inventive use of the latest STN technologies and Vertical Alignment Displays.
The best advice we can give, if your design has exceeded its power budget, is to think carefully about the features and effects your user interface needs to deliver.
An example of our custom monochrome LCD solution designed for smart energy metering application.
We can then work with you to decide how best to achieve your goal within any other constraints that may be in place, such as size, colour, or electromagnetic compatibility. That way, with our help, you can be sure your user interface will meet all the needs of your application, within important limits such as size and power consumption.