What is the thickness of a 3.4 inch 480x480 TFT panel?

If you’re hunting for a 3.4 inch 480x480 TFT panel, the first thing you’ll want to know is its thickness—because that single number can make or break your enclosure design, bezel clearance, or embedded system layout. The straightforward answer: the typical total thickness of a standard 3.4 inch 480x480 TFT LCD module, including the cover glass, polarizer, and backlight assembly, ranges from 2.8 mm to 3.5 mm, depending on the specific configuration and whether it includes a touch panel or additional optical bonding. For the bare display module without touch, the thickness usually sits around 2.95 mm ±0.2 mm, with the glass substrate itself being about 0.5 mm to 0.7 mm thick, the backlight stack adding 1.8 mm to 2.2 mm, and the polarizer films contributing roughly 0.15 mm to 0.25 mm on each side. That’s not a universal spec, though—different manufacturers tweak the stack-up based on brightness targets, mechanical robustness, and interface options like SPI or RGB. For example, the 3.4 inch 480x480 transmissive tft display from DisplayModule, model DM-TFT34-486, has a documented thickness of 3.2 mm for the standard version, which includes a 0.4 mm cover glass and a 2.0 mm backlight unit. That’s a solid middle ground for handheld or IoT devices where you need decent brightness (around 350 cd/m² typical) without adding bulk.

Let’s break down the mechanical layers in detail, because thickness isn’t just a single measurement—it’s a stack of components with tolerances that matter in real-world assembly. The active area of a 3.4 inch 480x480 TFT is about 69.12 mm x 69.12 mm (assuming a square pixel pitch of 0.144 mm), and the overall module outline is typically 76.5 mm x 76.5 mm, with a thickness that varies by design. The glass cell itself, which holds the liquid crystal layer, is usually 0.5 mm to 0.7 mm thick for a small panel like this, with the LC layer being only a few microns (typically 3-5 µm) sandwiched between two glass substrates. On top of the front glass, you’ll find a polarizer film that adds 0.15 mm to 0.25 mm, and sometimes an anti-glare or anti-reflection coating that’s another 0.05 mm to 0.1 mm. The backlight unit, which is the thickest component, consists of a light guide plate (LGP), a reflector sheet, diffuser films, and LED strips. For a 3.4 inch panel, the LGP is typically 0.8 mm to 1.2 mm thick, with the diffuser and prism films adding 0.3 mm to 0.5 mm combined, and the reflector sheet adding another 0.1 mm. The total backlight stack, including the LED PCB (often 0.6 mm to 0.8 mm thick), can range from 1.8 mm to 2.5 mm. If the display includes a capacitive touch panel (CTP), that adds another 0.8 mm to 1.2 mm for the glass sensor and cover lens, plus a bonding layer of 0.1 mm to 0.2 mm if optically bonded. So, a full module with touch can easily hit 4.0 mm to 4.5 mm total thickness.

Now, why does thickness vary so much across different suppliers? It comes down to the backlight design and the interface board. Panels using SPI (Serial Peripheral Interface) often have a thinner driver PCB because the data lines are fewer, while RGB (Red-Green-Blue) interfaces require more parallel traces and sometimes a larger flex tail or rigid PCB, which can add 0.2 mm to 0.5 mm to the overall thickness. For instance, the DM-TFT34-486 uses a 24-pin FPC (flexible printed circuit) that’s 0.3 mm thick, bonded to the glass with an anisotropic conductive film (ACF) that’s about 0.05 mm. The driver IC, typically a COG (chip-on-glass) package like the ILI9488 or ST7796, is mounted directly on the glass and adds negligible thickness (the IC itself is 0.3 mm to 0.5 mm, but it’s recessed into the glass edge). The backlight in this model uses 6 white LEDs in series, with a total forward current of 60 mA, and the LGP is 1.0 mm thick, giving a brightness of 350 cd/m². If you opt for a higher brightness version (say 500 cd/m²), the backlight stack might increase to 2.5 mm because of thicker diffuser films or an additional prism sheet. Similarly, panels with a wide viewing angle (like IPS technology) often have a slightly thicker LC cell (0.7 mm) compared to TN panels (0.5 mm), because IPS requires more complex electrode structures and alignment layers.

Let’s put some hard numbers into a table to make it crystal clear. Below is a comparison of typical thickness contributions for a 3.4 inch 480x480 TFT panel, based on common configurations from major manufacturers like Tianma, BOE, and DisplayModule. Note that these are nominal values; actual tolerances are usually ±0.1 mm to ±0.2 mm per layer, so the total can vary by up to 0.5 mm from batch to batch.

Beyond the raw numbers, you need to consider how thickness affects thermal performance and mechanical stress. A thinner backlight (say 1.8 mm total) might use a thinner LGP, which can cause hot spots near the LEDs if the diffuser films aren’t optimized. For a 3.4 inch panel running at 350 cd/m², the LED junction temperature can reach 50-60°C in a sealed enclosure, and a thinner stack (under 2.5 mm) may have less thermal mass to dissipate heat, potentially reducing LED lifespan. Conversely, a thicker backlight (2.5 mm) with a 1.2 mm LGP and two prism films can achieve 500 cd/m² with better uniformity, but it adds weight and bulk—about 12 grams for the thinner version versus 18 grams for the thicker one. The glass thickness also matters for drop resistance: a 0.7 mm front glass is more robust than 0.5 mm, but it increases the total module thickness by 0.2 mm and adds about 2 grams. If you’re designing a wearable or a handheld device, every 0.1 mm counts, especially when you’re trying to fit a battery, PCB, and enclosure within a 10 mm profile.

Another angle: the interface and driver IC placement can influence the effective thickness at the edges. Many 3.4 inch 480x480 TFT panels use a COG driver IC that’s bonded to the glass along one edge, which adds a local thickness bump of 0.3 mm to 0.5 mm over a 3-5 mm wide area. That’s not usually included in the “active area” thickness spec, but it can interfere with bezel design if you’re using a tight frame. For example, the DM-TFT34-486 has a COG driver on the bottom edge, and the FPC exits from the same side, so the overall thickness at the connector area is 3.5 mm (including the FPC reinforcement). If you’re using a ZIF connector, the mating height adds another 1.0 mm to 1.5 mm, so you need to account for that in your mechanical stack-up. Some panels use a TCP (tape carrier package) instead, which can reduce the edge thickness to 0.2 mm, but that’s less common for small square panels.

Let’s talk about real-world measurement methods. Thickness is typically measured with a micrometer or a caliper at the center of the active area, but you should always check the datasheet’s “mechanical drawing” section, which usually specifies the outline dimensions and the “total thickness” with a tolerance. For a 3.4 inch panel, the drawing might show a thickness of 3.0 mm ±0.2 mm, but that’s for the module only—excluding any protective film or shipping tape. I’ve seen cases where a supplier lists 2.8 mm, but that’s the glass cell thickness without the backlight, which is misleading. Always ask for the “module thickness” or “total thickness including backlight and FPC.” Also, if the panel is advertised as “ultra-thin” (like 2.5 mm), it likely uses a 0.4 mm glass and a 1.5 mm backlight, which sacrifices brightness (often below 250 cd/m²) and mechanical strength. That might be fine for a prototype, but not for a product that needs to survive a 1-meter drop test.

Another factor: optical bonding. If you’re bonding a cover glass or a touch panel to the TFT with optically clear adhesive (OCA), the total thickness increases by 0.1 mm to 0.2 mm per layer. For a 3.4 inch panel, a common stack is 0.5 mm cover glass + 0.1 mm OCA + 0.5 mm TFT front glass, which adds 1.1 mm to the front side. That’s why many industrial displays come with a “cover lens” option that’s already bonded, pushing the total thickness to 4.5 mm or more. The DM-TFT34-486, for instance, offers a variant with a 1.0 mm thick cover glass bonded with OCA, bringing the total to 4.2 mm. That’s a good trade-off for scratch resistance and readability in sunlight, but it adds weight and cost.

I’ve also seen thickness variations due to the backlight drive method. Some panels use a constant current driver IC on the FPC, which adds a small SMD component (like a 0.3 mm tall inductor or capacitor) that can increase the local thickness by 0.2 mm. If you’re using a separate LED driver on your main PCB, you can avoid that, but then you need to route the LED anode/cathode traces. The DM-TFT34-486 includes a built-in backlight driver on the FPC, so the FPC thickness is 0.4 mm at the driver area, but the rest of the FPC is 0.3 mm. That’s a detail that’s easy to miss in a datasheet, but it can cause issues if you’re routing the FPC through a tight slot.

Finally, let’s look at how thickness impacts the display’s optical performance. A thicker backlight stack (with more diffuser films) generally improves luminance uniformity—you might see a 5% to 10% better uniformity (e.g., 80% vs 75% at the corners) compared to a thinner stack. But the trade-off is that the display becomes slightly more prone to “mura” (brightness non-uniformity) if the films are not perfectly aligned. For a 3.4 inch panel, the typical uniformity spec is 80% minimum, but a 2.8 mm thick module might only achieve 75% at the edges, while a 3.5 mm module can hit 85%. Similarly, the viewing angle is affected by the polarizer thickness and the LC cell gap, not directly by the module thickness, but a thicker cell (0.7 mm) can improve contrast ratio at wide angles (e.g., 300:1 at 60° for IPS vs 100:1 for TN). So, if you need high contrast for a medical or industrial display, you might want a thicker panel with an IPS cell, which pushes the total thickness to 3.5 mm or more.

In short, the thickness of a 3.4 inch 480x480 TFT panel is not a single number—it’s a design variable that you can tune based on your brightness, durability, and cost targets. The most common range is 2.8 mm to 3.5 mm for a bare module, with 3.2 mm being a sweet spot for many applications. Always check the mechanical drawing, ask for the tolerance, and consider the FPC and connector heights. And if you’re looking for a reliable option with a documented 3.2 mm thickness, the DM-TFT34-486 is a solid choice, with its 350 cd/m² brightness, SPI/RGB interface, and 0.4 mm cover glass. Just remember to account for the 0.3 mm FPC thickness at the connector area, and you’ll be fine.