TN, IPS, VA and STN: Which Glass Mode Should You Specify?

Glass mode decides how the display looks from where the operator actually stands. IPS holds colour and contrast off-axis and is the safe default for a panel people approach from any direction. TN is cheaper and faster but wants to be looked at straight on. VA and VATN give a near-black background and the most premium front panel. STN and FSTN are the monochrome workhorses where power and cost matter more than colour.

Written by the Junxian applications engineering team. Figures quoted for “our models” are calculated from the 103 models on this site that carry a full parameter set, so they change when the catalogue changes.

What is the difference between TN, IPS and VA?

All three are liquid crystal modes - different ways the crystals are arranged and switched - and the arrangement decides the viewing cone, the contrast and the response time. TN twists the crystal 90 degrees and switches fastest; it is the cheapest to make and its weakness is that contrast and colour shift as you move off axis, particularly from below. IPS switches the crystals in the plane of the glass, so what you see barely changes across a wide cone - that is why it dominates modern panels. VA aligns them vertically, blocking light more completely in the off state, which gives the deepest black and the highest contrast ratio, at the price of slower response.

TFT vs IPS: why that is not really a choice

The two words describe different layers of the same panel. TFT - thin-film transistor - is the active-matrix backplane: one transistor per sub-pixel, holding its charge between refreshes, and almost every colour LCD module is built on one. IPS, TN and VA describe the liquid crystal on top of that backplane. So an IPS panel is a TFT panel, and the comparison that matters when you specify is IPS against TN or VA. A listing that says only 'TFT' is often a TN panel - check the glass-mode line of the specification. On our product pages the display type is its own row for exactly this reason, and our IPS guide goes through what IPS changes in numbers you can put in a specification.

Which one should I actually specify?

Ask where the operator's eyes are. A machine panel read from below while someone stands beside it, a handheld tilted in the hand, a display in a lid that opens to different angles - all IPS. A fixed console the user sits in front of, where cost matters more than the last few degrees of viewing angle - TN is honest engineering, not a downgrade. A front panel that should look black and premium when switched off, with bright characters when on - VA or VATN segment glass. A meter that has to run for years on a battery - monochrome STN or FSTN, and skip the backlight where daylight will do.

What our published models actually use

Generic comparisons stop being useful when it is time to order, so here is the mix across our own catalogue - what exists, in which sizes.

Read from the display type field of each published model. Some models are listed as a combination (IPS/TN, STN/FSTN) because the same glass is offered both ways - those are counted under each mode they support.

Viewing direction: the parameter people forget

Monochrome STN and segment glass has a preferred viewing direction, usually written as 6 o'clock or 12 o'clock. It is a physical property of the glass, decided when the part is made, and it cannot be changed in firmware. A panel-mounted meter read from above and a handheld read from below need opposite builds. If your product is sometimes wall-mounted and sometimes desk-mounted, say so - a wide-view or all-o'clock build exists and should be chosen deliberately rather than discovered at the sample stage.

Contrast ratio is measured in the dark - your product is not used there

Datasheet contrast is measured in a dark room. In a lit room, ambient light reflecting off the surface raises the black level and the effective contrast collapses long before the datasheet number becomes relevant. That is why an anti-glare surface or optical bonding often does more for perceived quality than choosing the glass mode with the biggest contrast figure - and why we ask where the display sits before recommending a mode.

Response time: when it matters and when it does not

TN is fastest, VA slowest, IPS in between. For an HMI showing values, a menu or a gauge, none of them is too slow. It becomes real in two cases: sub-zero operation, where liquid crystal response slows dramatically and a VA panel can visibly smear at -20 °C; and any moving content such as a camera preview. If your product does either, raise it early - it changes the recommendation more than the room-temperature datasheet line suggests.

What this costs

Roughly, and in the order you will feel it: monochrome STN and FSTN are the cheapest, TN colour next, IPS a step up, and custom VATN segment glass carries tooling (1,000 pcs) but a very low unit cost at volume. The mode is rarely the biggest line in a display quotation - size, touch and brightness usually are - so choosing TN to save money on a panel that needs IPS is a poor trade. Choose the mode for the viewing geometry, then control cost with size, brightness and touch.