Find a TFT LCD by Size and Resolution

Quick answer

Choosing a TFT by size and resolution works when the two are derived from the job the display has to do, rather than picked from a list. Size comes from how much content must be legible at the operator's viewing distance; resolution comes from the smallest element that has to be readable. Set those two, then let the interface and the environment narrow the field. This page sets out that order.

Start from the content, not the catalogue

Before looking at panels, write down the busiest screen the operator will see — the one with the most values, alarms and controls — and the distance it is read from. That single description fixes the diagonal more reliably than any preference. A screen with four large values can be read from two metres on a 5 inch panel; the same content with a trend graph and an alarm banner needs 7 or 10 inches at that distance.

Diagonal	Comfortable viewing distance	Content it carries well	Typical placement
2.4 to 3.5 inch	30 to 50 cm	a few readings, status icons	handheld tools, compact instruments
4.3 to 5.0 inch	40 to 70 cm	one process view, soft keys	machine-mounted panels
7.0 inch	50 to 100 cm	full process view with trends	control cabinets, equipment fronts
10.1 inch	1 m and beyond	multi-zone overview, SCADA view	operator stations, line supervision
15.6 inch	1.5 m and beyond	dense supervisory content	control rooms, large HMIs

Resolution: readable, not maximum

More pixels on the same diagonal means finer detail and smaller on-screen elements. That is good for a dense supervisory screen read at a fixed position, and bad for a panel operated by a gloved hand, where touch targets need physical size. The test is the smallest text or control that must be usable: size it in millimetres at the viewing distance, then choose a resolution that renders it comfortably rather than the highest available.

Common size and resolution pairings

• 3.5 inch, 320x240 or 320x480: compact instruments and handheld tools, often on an MCU bus or SPI.
• 4.3 inch, 480x272: the long-standing machine-panel standard, usually RGB.
• 5.0 inch, 800x480: a full process view in a small footprint, RGB or LVDS.
• 7.0 inch, 800x480 or 1024x600: the most widely used industrial HMI size, RGB or LVDS.
• 10.1 inch, 1024x600 or 1280x800: operator stations and supervisory views, usually LVDS.

Then let the environment narrow it

Once size and resolution are fixed, three parameters usually decide between the remaining candidates. The interface should be one the host processor drives natively, to avoid a bridge. The brightness follows the ambient light at the operator position, from roughly 300 to 500 cd/m2 indoors to 1000 cd/m2 and above for sunlight-readable use. The temperature band is measured at the module in a prototype, not taken from climate data. Those three typically reduce a long list to one or two parts.

Confirming the choice

Before committing, check three practical things: that the smallest text is legible at the real viewing distance, that the touch targets suit the way the operator works, and that the module will still be obtainable for the life of the product. The first two are caught by drawing the busiest screen at true scale; the third by choosing a module stocked and supported for 5+ years of supply continuity.

Representative RONEN modules by size

• RG-T024BQSA-01 — 2.4" 240x320 IPS, 500 cd/m2, RGB/SPI/MCU
• RG-T035HLSWA-01 — 3.5" 320x240 IPS, 1200 cd/m2, RGB, rated -30 C
• RG-T043BPSA-02 — 4.3" 480x272 IPS, 1000 cd/m2, RGB
• RG-T050BWSA-02 — 5.0" 800x480 IPS, 1000 cd/m2, RGB
• RG-T070BAHA-02 — 7.0" 1024x600 IPS, 1000 cd/m2, LVDS
• RG-T101BFHA-01 — 10.1" 1920x1200 IPS, 1200 cd/m2, LVDS
• RG-T156BFHWA-02 — 15.6" 1920x1080 IPS, 1000 cd/m2, LVDS, rated -30 C

Frequently asked questions

How do I choose between 7 and 10 inch?

From the viewing distance and the content. If the operator stands a metre or more away, or the screen has to carry a multi-zone overview, 10 inch is usually right. At arm's length with a single process view, 7 inch is generally enough and easier to mount.

Is a higher resolution always better?

No. Higher resolution makes on-screen elements smaller, which is an advantage for dense content read at a fixed position and a disadvantage when operators need large touch targets or read the screen at a distance.

Which resolution suits a 7 inch industrial panel?

800x480 and 1024x600 are the common industrial formats. 800x480 suits simpler interfaces with larger elements; 1024x600 carries more content where the operator is closer and the GUI is denser.

What should I check before committing to a size?

Draw the busiest screen at true scale and read it from the real operating position. That test catches text that is too small and touch targets that are too tight, both of which are expensive to discover after tooling.

Quick Answer

When the original part number is unknown or unprintable, reverse lookup works: measure size and active area, read resolution from the test pattern or host config, identify the interface from the connector, then match against a catalog. Our catalog covers 190+ standard modules — 128 RGB, 27 LVDS, 20 MIPI and 5 SPI — across the sizes tabulated below. Send us the three parameters and we return matching part numbers with datasheets.

Two sizes now have dedicated main pages with the full model list and verified specifications: 8.0 inch TFT LCD modules (800x600, 1024x768 and 800x1280 portrait, 250–1200 cd/m²) and 15.0 inch TFT LCD modules (1024x768 IPS, LVDS, 450 cd/m²).

“Most “drop-in replacement” claims quietly break at the pin level. The fastest way to a real cross-reference is the old part number plus the failure you observed.”