This article addresses monochrome displays, and in particular: selecting the best monochrome LCD screen display for your product (i.e. those with a single color). Monochrome displays are limited to one color for the characters and a different color background. They are unlike color displays—such as TFT (Thin Film Transistor), OLED (Organic Light-Emitting Display) and Field Sequential Color Displays (FSC LCD) where both the characters and the background of a color display can change color; monochrome displays cannot change color.
This is part 3 in a series of LCD basics to provide information on the best LCD display option for your product from Focus Display Solutions in Chandler AZ. The previous articles have discussed color LCD technology.
See Part 2 in this series.
There are four main monochrome technologies. They are:
- Static or segment displays
- Character or alpanumeric dislays
- Graphic or dot matrix displays
- EBT or excellent black technology displays
This article covers the first technology—Segment LCD displays.
Segment LCD displays have several names within the industry; you may also know them as static displays, direct drive LCD screen displays or multiplex LCD glass. This technology has been in use for several years and due to its popularity it won’t fall out of favor anytime soon.
Primarily, you will see static LCD screen displays used in applications that are lower cost and are required to display numbers and a few simple icons, like a battery indicator. Common applications consumers encounter with this technology include gas pumps, power meters, and thermometers. Statics LCD screen displays contain both seven segment numbers and icons.
What is a seven segment?
Likely you’ve been looking at seven segment numbers for years on various products and didn’t realize their universal and simplistic use. A seven segment number’s versatility is illustrated in the ease of turning ON or OFF the individual segments of the character in order to create any number from 0 to 9 and several letters such as C, A, b E, L, and F. Below is a seven segment LCD module.
What is an icon?
Icons are all of the simple symbols that quickly communicate through images or outlines by representing a set of words. Examples of icons include low battery, AM/PM and C/F(Celsius/Fahrenheit). Icon images are supplied by the product designer to the display manufacturer and are limited in their diversity only by the imagination of the designer. Manufacturers work with designers to facilitate any customization needs for their application and usually only require a one-time tooling fee to add the icons to the customer‘s display. Below are examples of icons that are used on the static LCD screen display of a camera.
Static LCD screen displays require low power
One of the main reasons for the popularity of static LCD screen display is their low consumption of power. Products that are powered by battery have a low power budget and value power conservation as the most important quality in this display. In most applications, the display is the one electronic component with the largest power consumption. As a general rule, a static display with no backlight can operate on as little as 2uA (micro-amps) per cm^2 .
Watches, thermometers, and portable test equipment are products that require low power consumption.
Static LCD screen displays are low cost
Although low power consumption is important, so is low cost for many products. Low cost means that it is more reasonable to use this technology even in products that are disposable. One example of this is a glucose meter (or glucometer). These products are manufactured in high volume and in many cases are disposable. The cost of a static meter is determined by the size of the glass. The larger the glass, the higher the cost. Direct drive LCD screen displays with no backlight can cost as little as .40 cents/each in large quantities and with prices like that there is no reason not to use the technology.
The main reason for the lower cost of a static LCD screen is that they do not contain a controller/driver (C/D) chip. The lack of the C/D chip means two key things:
- The engineer or designer will need to invest more time into programing the software, aka firmware, to operate the display.
- Each segment will be connected to each pin connection if this is a direct drive, or each pin will connect to three or four segments if this is a multiplex drive.
Custom Static LCD screen display requires minimal investment
Henry Ford once said, “you can have your car in any color, as long as it is black.“ Times have changed. Consumers want the product to fit their life style, not the other way around. Static displays offer a fantastically diverse and useful technology at a low cost.
The designer can have the display built to the size requested and with customized icons for a tooling fee as low as $900. This fee is dependent on many variables including the type of glass but becomes negligible when you think of what a value-add the customization is to your products‘ identity.
Advantages of a static LCD screen display:
- Lowest cost of any LCD technology
- The display can be customized with a low tooling cost
- Lowest power consuption of any of the four technologies—static, character, graphic, or EBT display units.
Disadvantages of static LCD displays:
- Can only display a few letters or icons
- Does not contain a controller/driver chip
- MOQ's (minimum order quantities) of 1,000 or more for customized displays
- Generally do not contain a backlight
If cost is a concern and your product will be powered by a battery, have a low power budget, and you value power conservation as the most important quality then the Segment LCD display may the best monochrome LCD screen display for your product. The simplistic use and ease of turning ON or OFF the individual segments of this display make this a very useful and diverse technology.