Engineers selecting an LCD for a new product will encounter terminology that affects display selection, customization, production planning, and lifecycle management.
Understanding these terms early can make it easier to compare display options and communicate requirements with a supplier.
Here are nine LCD terms that OEM engineers should understand.
1. MOQ – Minimum Order Quantity
MOQ stands for Minimum Order Quantity. It is the minimum production quantity associated with a particular product or manufacturing configuration.
MOQ can vary significantly depending on whether the display is:
- A standard in-stock product
- A standard display requiring production
- A modified-standard display
- A custom monochrome LCD
- A customized TFT assembly
Focus LCDs has no minimum order quantity on in-stock standard displays.
Custom-build requirements are project-specific because the display may involve unique glass, FPCs, PCBs, backlights, touchscreens, cover glass, or other components.
For custom projects, expected annual usage is useful information to provide during the initial engineering discussion.
2. Lead Time
Lead time describes the time required to move from an order or project stage to the required delivery or completion point.
For LCD projects, there is not one universal lead time.
Timing can depend on factors such as:
- Current inventory
- Display technology
- Customization
- Engineering review
- Drawing approval
- Tooling
- Prototype evaluation
- Component availability
- Production requirements
An in-stock standard display may be available immediately, while a custom display program involves additional engineering and production steps.
For a more detailed explanation, see LCD Lead Times: What OEM Engineers Should Consider.
3. Contract Manufacturer
A contract manufacturer, commonly abbreviated as CM, manufactures or assembles products on behalf of another company.
In many OEM programs, the OEM is responsible for the product design and approved bill of materials, while the contract manufacturer purchases components and builds the finished equipment according to those requirements.
For an LCD supplier, this can mean working with both:
- The OEM engineering team responsible for selecting and approving the display
- The contract manufacturer responsible for purchasing or assembling it
It is important that part numbers, drawings, approved configurations, and change requirements remain clearly documented so everyone is working from the same display specification.
4. Tooling or NRE
Tooling and NRE, or Non-Recurring Engineering, refer to one-time work required to develop certain custom display solutions.
Depending on the project, this can involve:
- LCD glass development
- Mechanical drawings
- Electrical design
- FPC development
- PCB or PCBA work
- Backlight configuration
- Touchscreen integration
- Cover glass
- Prototype preparation
- Manufacturing processes or fixtures
Not every custom project includes the same tooling.
The scope, prototypes, documentation, production requirements, and other commercial terms should be confirmed for the individual project.
For more information, see Custom LCD Tooling: What OEM Engineers Should Expect.
5. RoHS
RoHS stands for Restriction of Hazardous Substances.
It refers to requirements that restrict certain hazardous substances in electrical and electronic equipment.
For an engineer selecting a display, RoHS status may be part of the product’s material-compliance requirements and should be verified as part of component selection and documentation.
Focus LCDs supports RoHS-compliant products.
Engineers working under specific regulatory or compliance requirements should confirm the applicable documentation for the selected part number.
6. Sunlight-Readable Display
A sunlight-readable display is designed to remain usable under high ambient-light conditions.
There is no single brightness number that automatically makes every LCD sunlight readable.
Readability depends on several characteristics, including:
- Display technology
- Backlight brightness
- Contrast
- Polarizers
- Optical stack
- Reflections
- Viewing angle
- Ambient lighting
- Cover glass
- Optical bonding
Monochrome reflective and transflective displays can use ambient light to improve readability in some applications.
TFT displays may use higher-brightness backlights, optical treatments, bonding, or other design approaches depending on the environment.
The correct solution should be evaluated under the lighting conditions in which the finished product will actually operate.
7. Nits
A nit is a unit used to describe luminance.
One nit is equivalent to one candela per square meter, or cd/m².
LCD backlight specifications commonly use nits to describe brightness.
Higher brightness can improve visibility in high ambient light, but it can also affect:
- Power consumption
- Thermal performance
- Backlight life
- Battery requirements
For this reason, engineers should not select a display based on brightness alone.
The appropriate luminance depends on the display technology, optical construction, environment, and power requirements of the finished product.
8. Backlight Life
Many LCD modules use LED backlights.
LED brightness gradually decreases during operation, so backlight specifications may describe the expected time required for brightness to decline to a defined percentage of its original level.
When comparing displays, engineers should review how the backlight-life specification is actually defined rather than assuming every supplier measures it the same way.
Factors affecting LED backlight life can include:
- Operating current
- Temperature
- Thermal management
- Duty cycle
- Backlight configuration
Driving an LED harder to achieve greater brightness can affect both power consumption and long-term performance.
For additional information, see The Half-Life of LED Backlights.
9. EOL — End of Life
EOL, or End of Life, indicates that a component or product is being discontinued.
For an OEM, an LCD reaching EOL can create a significant engineering problem because the display may be integrated into:
- The enclosure
- PCB
- Firmware
- Touchscreen
- User interface
- Qualification documentation
- Manufacturing procedures
Replacing it may therefore require considerably more work than replacing a simple commodity component.
Engineers should consider lifecycle risk when selecting an LCD, particularly for products expected to remain in production or service for many years.
Questions worth asking include:
- What is the expected product lifecycle?
- Is the display appropriate for a new design?
- Which components are likely to affect long-term availability?
- What happens if the display is discontinued?
- How difficult would replacement or requalification be?
For more information, see LCD lifecycle risk management for OEM programs.
Monochrome and TFT Customization Are Different
One related term that often causes confusion is custom LCD.
Customization does not mean the same thing for every display technology.
For monochrome LCDs, Focus LCDs can customize the LCD glass itself, including dimensions, shape, resolution, segment layout, and other characteristics.
For TFT displays, Focus LCDs does not modify the TFT glass itself.
Instead, customization can be applied around an established TFT panel through components such as:
- Backlights
- FPC cables
- Touchscreens
- Cover glass
- Optical bonding
- Adhesives
- Custom PCB or PCBA when incorporated into the LCD assembly
For more information, see Custom TFT Displays: What Can Actually Be Customized?.
Why These LCD Terms Matter
Understanding LCD terminology makes it easier to evaluate a display beyond basic size and resolution.
MOQ affects production planning. Lead time affects scheduling. Tooling determines what is involved in customization. Nits and backlight life affect optical and power decisions. EOL affects the long-term viability of the product.
For OEM engineers, the most useful question is not simply “Which display works today?”
It is also:
“Which display will work mechanically, electrically, optically, and operationally throughout the life of our product?”
Focus LCDs works with OEMs, design houses, and contract manufacturers to evaluate standard and custom display requirements from prototyping through production.
Contact Focus LCDs engineering support to discuss the display requirements for your project.
