Choosing a Color LCD for Mining Safety Equipment
Safety first. How many times have you seen this sign when passing construction sites. Mining safety is critical, which makes safety equipment big business worldwide. The mining industry, among others, tracks several variables such as dangerous gases and air quality through the use of portable handheld test equipment.
Many of these handheld monitors contain an LCD of some type. In the last few years, many devices have looked to upgrade from a monochrome LCD (single color) to a TFT LCD for various reasons:
- TFTs can display between 64,000 to 64,000,000 unique colors with each pixel.
- TFTs have much higher resolutions than most monochrome displays.
- They give the product the “smartphone” feel that everyone has familiarity with.
TFTs do draw more power than a monochrome display but their range of colors and brightness offer advantages in the mining field.
Below are a few considerations when selecting the best TFT for your air monitoring device.
PROTECTIVE COVER AND HARDENED GLASS
With handheld products, there is a good possibility of them being dropped. TFTs are manufactured with ITO glass, which easily scratches or breaks. We can supply chemically strengthened glass, similar to Gorilla Glass ® and other brand names. This material added on top of the TFT greatly reduces damage.
For extra protection, your LCD supplier can add a protective cover over the TFT glass. Not only does the overlay provide additional protection, but it is also easier to replace than the TFT if damaged.
Protective covers can include stenciling (Black and white or color) of the company’s name or model number.
COLDER TEMPERATURE OPERATION:
Most TFTs operate down to -20C, but many mining operations require their equipment to function in colder temperatures. When the display becomes too cold, it stops working until the temperature rising above the -20C.
To allow operation in cold temperatures, Focus LCDs offers TFTs in multiple sizes with an extended temperature range allowing operation from -30C to 80C.
Some requirements, however, call for a -40C operating temperature. For these requirements, there are various types of heaters that may be used. The most common option is a heat film applied to the top layer of glass.
Insulating your TFT will go a long way. This saves power since the heaters will only be powered “on” a fraction of the time.
WHAT SIZE OF TFT?
Choose the best size for your product. TFTs are available through Focus LCDs ranging from 1.3” to 10.4”. Most handheld products stay between 1.4” to 4”.
DAYTIME/NIGHTTIME OPERATION:
Products containing TFTs must be readable indoors (underground or darker environments) and outdoors to compete with bright lights such as sunlight.
Most TFTs contain a transmissive polarizer which provides a brighter backlight but is difficult to read in direct sunlight. The brightness of a TFT with a transmissive polarizer is recommended to exceed 700 nits for readability in sunlight.
When designing your TFT, it is important to consider an adjustable brightness feature. Adjusting brightness in different environments will save power and won’t blind the user.
Note: A Nit is a measure of a display’s brightness. Here are some more details.
The other option is a TFT with a transflective polarizer. TFTs with transflective polarizers are readable in bright ambient light without the backlight on (the backlight uses more power than the LCD itself), and they can be read in the dark with the backlight on.
RESOLUTION:
Resolution is also known as called pixel count. This is the number of pixels on the display. With a high pixel count, the LCD has more detail but more processing power will be needed to drive all of those pixels.
TOUCH PANEL:
To be or not to be. Touch panels (TP) have changed our lives with phones, tablets, and medical equipment, eliminating external controls such as dials and buttons.
There are two main TP options: capacitive and resistive.
Capacitive allows for zoom, pinch, and multi-touch, but most will not work when the user is wearing gloves. Resistive is better for harsh environments, but still may have issues in very adverse conditions. For more details, read our article on the differences between a resistive touch panel (RTP) and a capacitive touch panel (CTP).
In many cases, no touch panel may be the best option for an industrial application where people wear gloves or where dust, and grime will damage the touch panel. It may be best to add external control to your measurement device.
INTRINSIC DISPLAYS:
With many different intrinsic safety ratings worldwide, we will build the display to meet your requirements
Intrinsic designs are products that have a very low probability to ignite when in explosive situations such as mines or gas pumps. Here is an article with more details.
Most products used in mining environments must meet some type of testing to make sure they are safe. While it is the customer’s responsibility to confirm the display specifications meet the intrinsic safety standards for which they are applying, we are able to produce custom options to adjust some of the necessary specs as needed and we will be available to handle requests from the intrinsic safety certification body for any specific information throughout the process.