How to Review a TFT LCD Mechanical Drawing and FPC Pinout

The mechanical drawing is the common reference for the enclosure, PCB, display supplier and assembly team. Review it before enclosure tooling and PCB layout are frozen. A model number or diagonal size is not enough to establish interchangeability.

Module outline dimensions

Check overall width, height and maximum thickness, including components, stiffeners, adhesive and touch stack where applicable. Confirm which dimensions are nominal and which include tolerances. The enclosure must not apply unintended pressure to the active display area or flexible tail.

Active area and viewing area

The active area is the illuminated pixel region. The viewing area or bezel opening may be larger. Align the visible content, cover-lens window and enclosure opening to the correct reference, and verify centering tolerances. A small offset can become obvious when a printed cover window is narrow.

Reference datums and tolerances

Dimensions should be interpreted from defined datums rather than chained assumptions. Review tolerance accumulation across the LCD outline, cover glass, housing and PCB connector. Ask which features are controlled during production and which are only reference dimensions.

FPC exit direction and bend zone

Confirm the tail exit side, tail length, copper side, stiffener orientation and minimum bend strategy. Avoid placing a fold line across components or the stiffener transition. The FPC must reach the connector without tension after assembly tolerances are included.

If a standard panel is optically suitable but the tail does not fit, review the custom TFT LCD FPC and connector options.

Connector definition

Match pitch, contact count, mating direction, contact side and connector height. Connector families that look similar may not mate. Include the exact connector manufacturer and part number on the PCB bill of materials when possible.

Pin assignment and electrical checks

• Confirm signal names, sequence and whether numbering is viewed from the component or contact side.
• Check I/O voltage, analog supply, backlight anode/cathode and current requirements.
• Identify reset, chip select, synchronization, clock and data lines.
• Verify unused pins, test points and required pull-up or pull-down states.
• Compare interface timing and initialization code with the controller IC.
• Review power-on, reset and backlight sequencing.

Touch and cover-lens stack

For PCAP or RTP assemblies, confirm sensor outline, touch active area, tail location, controller location, cover-lens outline, printing, holes, corner radius and total stack thickness. Optical bonding and perimeter adhesive also need defined thickness and width.

Drawing release checklist

1. Overlay the display active area and outline on the enclosure CAD.
2. Confirm PCB connector position and assembly insertion route.
3. Review the FPC in both installed and service positions.
4. Check bezel pressure, gasket compression and adhesive clearances.
5. Verify every pin against the host schematic.
6. Record the approved drawing revision in purchasing and production documents.

Product drawing references

Use the published drawings for the DS-T020BQSA-01 2.0-inch portrait module, DS-T020BLIA-01 2.0-inch landscape module, DS-T021BCSA-02 2.1-inch round module, and DS-T023BCSA-01 2.3-inch MIPI module as practical starting references. Always request the controlled drawing before final release.