When an LCD used in existing OEM equipment becomes unavailable, an off-the-shelf replacement is not always available.
The original display may have unique dimensions, electrical characteristics, pin assignments, connectors, viewing requirements, or other features that were designed specifically for the product.
In these situations, a custom LCD panel may provide a path for replacing the discontinued display while minimizing changes to the existing equipment.
Focus LCDs works with OEM engineering teams to evaluate obsolete displays and determine whether an existing standard display, modified-standard product, or custom replacement is the appropriate approach.
When Is a Custom LCD Panel Necessary?
The first option should generally be to determine whether an existing display can satisfy the requirements of the original module.
A standard display may be appropriate when it provides acceptable compatibility with characteristics such as:
- Mechanical dimensions
- Viewing area
- Resolution or display format
- Connector location
- Pinout
- Interface
- Controller
- Operating voltage
- Backlight
- Viewing characteristics
When no standard display adequately satisfies the critical requirements, customization may be necessary.
The objective is not to customize the LCD unnecessarily. It is to preserve the characteristics that matter to the existing OEM product.
Start With the Original LCD Requirements
The more information available about the discontinued display, the easier it is to evaluate potential replacement options.
Useful documentation can include:
- Original manufacturer and part number
- Datasheet
- Mechanical drawing
- Electrical specifications
- Pinout
- Controller or driver information
- Connector or FPC details
- Backlight information
- Photographs
- Operating-temperature requirements
- Product assembly drawings
Engineers should also identify which requirements absolutely cannot change.
For example, changing the connector location may be unacceptable if the customer’s PCB and enclosure are already fixed, while another characteristic may have more flexibility.
What if the Datasheet Is No Longer Available?
Documentation for older LCD modules is sometimes incomplete or unavailable.
When that happens, photographs and physical samples may provide additional information.
Focus LCDs may also evaluate whether the display is suitable for reverse engineering.
Depending on the project, this can involve reviewing characteristics such as:
- Mechanical dimensions
- Viewing and active areas
- Connector or FPC
- Pinout
- Interface
- Controller
- Backlight
- Optical configuration
- Mounting features
The exact reverse-engineering process depends on the display and the information available.
For more detail, see LCD Reverse Engineering Services for Obsolete and Discontinued Displays.
Custom Monochrome LCD Panels
Monochrome technology provides significant flexibility for replacement projects because the LCD glass itself can be customized.
Depending on the application, Focus LCDs can customize characteristics including:
- Glass dimensions
- Glass shape
- Segment layout
- Resolution
- Character or graphic configuration
- Viewing mode
- Backlight
- Connector or FPC configuration
- Other components in the display assembly
This can be useful when an existing OEM product was designed around a monochrome display that is no longer available.
The replacement does not necessarily need to reproduce every aspect of the original module, but it should preserve the characteristics required by the host equipment.
Segment LCD Replacement
Segment displays can be highly application-specific.
The original LCD may contain unique numbers, icons, annunciators, symbols, or graphical elements that do not exist in any standard display.
In these cases, development of new LCD glass may be the most appropriate replacement approach.
Useful information includes:
- Segment artwork or drawings
- Glass dimensions
- Viewing area
- Pin assignments
- Drive requirements
- Viewing mode
- Backlight requirements
- Connector configuration
If the original artwork is unavailable, additional evaluation of the existing display may be required.
For additional design information, see our Custom Segment LCD Design Guide.
Character LCD Replacement
Character LCD modules can present a different set of compatibility requirements.
In addition to mechanical dimensions, engineers should review:
- Character format
- Character size
- Controller or driver
- Interface
- Pinout
- Connector location
- Backlight
- Viewing direction
Controller compatibility can be especially important because the existing product firmware may depend on the command structure of the original display.
A mechanically similar character display should therefore not automatically be considered an equivalent replacement.
Graphic Monochrome LCD Replacement
Graphic LCDs may require evaluation of:
- Resolution
- Active area
- Mechanical dimensions
- Controller
- Interface
- Pinout
- FPC or connector
- Backlight
- Viewing characteristics
If the original controller is no longer available, the engineering team should determine whether another controller can be integrated without unacceptable firmware or hardware changes.
The replacement strategy should be based on the complete system rather than display dimensions alone.
What About a Discontinued TFT?
TFT replacement projects are handled differently from monochrome LCD projects.
Focus LCDs does not modify the TFT glass itself.
Instead, the first step is identifying an existing TFT panel that can satisfy the important requirements of the application.
Customization can then be applied to components surrounding the TFT, including:
- Custom FPC cables
- Backlights
- Resistive or capacitive touchscreens
- Cover glass
- Optical bonding
- Adhesives
- Custom PCB or PCBA when incorporated into the display assembly
For more information, see Custom TFT Displays: What Can Actually Be Customized?.
Is a Drop-In Replacement Always Possible?
No.
The phrase drop-in replacement should be used carefully because true compatibility depends on more than the physical dimensions of the LCD.
A replacement may also need to preserve:
- Pinout
- Electrical interface
- Controller behavior
- Voltage requirements
- Mechanical mounting
- Connector position
- Firmware compatibility
- Optical characteristics
Sometimes all of these requirements can be maintained.
In other cases, the most practical replacement may require a controlled change to the customer’s PCB, firmware, enclosure, or other part of the product.
The engineering objective is to identify the solution that minimizes disruption while meeting the requirements of the existing equipment.
Controller and Firmware Compatibility
Controller compatibility is one of the most important considerations in many obsolete-display projects.
When the original controller can still be identified, the replacement can be evaluated against the existing firmware requirements.
If a different controller is necessary, engineers should determine whether its command set and behavior are compatible with the host product.
Firmware changes may be required when controller compatibility cannot be maintained.
This should be identified as early as possible because software changes can affect the scope of the replacement project.
Backlight Requirements
The backlight is another area that deserves careful review.
Older displays may use a backlight configuration that differs from current designs.
Important characteristics can include:
- Backlight technology
- Electrical requirements
- Brightness
- Mechanical dimensions
- Power consumption
- Connection method
- Operating environment
Changing the backlight can affect more than appearance. It may also affect the customer’s power architecture, PCB, connector, mechanical design, or thermal characteristics.
Can the Replacement LCD Be Improved?
A replacement project may provide an opportunity to evaluate changes to the original display.
Possible areas could include:
- Backlight performance
- Viewing characteristics
- Connector configuration
- Power requirements
- Readability
- Environmental performance
However, newer is not automatically better.
Any change should be evaluated against the existing product requirements before being incorporated into the replacement design.
The primary objective is to maintain a reliable display solution for the OEM equipment.
Does a Custom Replacement Require Tooling?
A custom LCD project may require tooling or NRE depending on the technology and level of customization.
The exact scope is project-specific.
Tooling may relate to items such as:
- LCD glass development
- FPC design
- PCB development
- Mechanical components
- Touchscreen or cover-glass integration
- Prototype preparation
- Other engineering activities
Pricing, production quantities, prototype arrangements, documentation, ownership provisions, and project schedules should be confirmed for the individual program.
For additional information, see Custom LCD Tooling: What OEM Engineers Should Expect.
MOQ for Custom Replacement LCDs
Production requirements differ by technology and project.
Factors can include:
- Type of LCD
- Level of customization
- Custom components
- Manufacturing requirements
- Expected annual usage
- Remaining product lifecycle
There is therefore no single MOQ that accurately represents every custom replacement display.
Providing estimated annual usage helps determine whether a custom solution is appropriate for the program.
Prototype Evaluation
When a custom replacement is developed, prototype evaluation may be an important step before production approval.
Depending on the display, engineers may need to review:
- Mechanical fit
- Viewing area
- Pinout
- Electrical operation
- Interface
- Controller behavior
- Firmware compatibility
- Backlight
- Optical performance
- Connector or FPC
- Operating environment
Prototype quantities and project schedules depend on the specific design and should be confirmed as part of the project.
Think Beyond the Immediate Shortage
An obsolete display can create an urgent purchasing problem, but the replacement decision should also consider the remaining life of the OEM product.
Useful questions include:
- How long will the equipment remain in production?
- How long will field-service demand continue?
- What is the expected annual usage?
- Which display requirements cannot change?
- Are PCB changes acceptable?
- Are firmware changes acceptable?
- Would a display change require qualification or documentation updates?
- Is the replacement expected to support production, service, or both?
These questions help determine how much engineering effort is appropriate for the replacement.
For more information, see LCD lifecycle risk management for OEM programs.
Standard Display or Custom LCD Panel?
The simplest solution should be considered first.
If an existing standard Focus LCD meets the critical requirements, it may avoid unnecessary custom development.
Focus LCDs maintains broad inventory of standard display modules in Chandler, Arizona, and in-stock standard products can ship the same day when applicable. focus_lcds_marketing_knowledge_…
When an existing standard display cannot adequately replace the obsolete module, a modified-standard or custom solution can then be evaluated.
The goal is to solve the engineering problem with the appropriate level of customization.
What Information Should You Provide?
To evaluate a discontinued LCD for custom replacement, provide whatever information is available:
- Original manufacturer
- Original part number
- Datasheet
- Mechanical drawings
- Photographs
- Pinout
- Interface
- Controller or driver
- Connector or FPC
- Backlight information
- Operating environment
- Expected annual usage
- Remaining product lifecycle
- Requirements that cannot change
It is not necessary to have every item before making contact. The available information gives the engineering team a starting point for determining the next step.
Start a Custom LCD Replacement Project
Focus LCDs works with OEMs, design houses, and contract manufacturers on standard, modified-standard, and custom display solutions. focus_lcds_marketing_knowledge_…
When an obsolete display cannot be replaced adequately by a standard module, a custom LCD panel may allow the existing equipment to remain in production or service without a complete product redesign.
Contact Focus LCDs engineering support and provide the original part number, datasheet, drawings, photographs, or other available information.
