Media68·
The overall dimensions of a 3.4 inch 480x480 TFT LCD display are typically 74.80 mm (width) by 74.80 mm (height) for the module, with an active area of 69.12 mm by 69.12 mm. This specific square format, driven by a 480x480 resolution, is a niche but highly functional size for industrial and embedded applications. The module’s thickness usually hovers around 2.5 mm to 3.0 mm, depending on the backlight and touch panel integration. For instance, the 3.4 inch 480x480 tft lcd display from DisplayModule, model DM-TFT34-485, measures exactly 74.80 mm x 74.80 mm for the glass and FPC (flexible printed circuit) combined, with a viewing area of 70.08 mm x 70.08 mm. The active area, where pixels actually light up, is slightly smaller at 69.12 mm x 69.12 mm, giving a pixel pitch of about 0.144 mm. This tight pitch means the display packs roughly 277 pixels per inch (PPI), which is sharp enough for detailed icons, small text, or data visualization without noticeable pixelation at typical viewing distances of 20 to 30 cm.
Let’s break down the physical structure. The display uses a TFT (thin-film transistor) backplane, typically amorphous silicon, with a resolution of 480x480 RGB pixels. Each pixel is composed of red, green, and blue sub-pixels, arranged in a stripe pattern. The sub-pixel size is roughly 0.048 mm by 0.144 mm, which is standard for this resolution class. The glass substrate is usually 0.5 mm to 0.7 mm thick, with a total stack-up including polarizers, color filters, and the liquid crystal layer. The backlight, often a single LED or a series of white LEDs, sits behind the TFT glass. For the DM-TFT34-485, the backlight is rated for 6 to 8 LEDs in series, consuming about 20 mA at 3.0 V to 3.3 V, producing a typical brightness of 350 to 400 cd/m² (nits). This brightness level is adequate for indoor use but may require a higher brightness variant (e.g., 600 to 800 nits) for direct sunlight readability. The module’s thickness is largely driven by the backlight diffuser and light guide plate, which add about 0.8 mm to 1.2 mm.
Interface and connectivity are critical for integration. Most 3.4 inch 480x480 TFT displays use a 4-lane MIPI DSI (Display Serial Interface) or a 24-bit RGB parallel interface. The DM-TFT34-485 specifically uses MIPI DSI, which reduces pin count and allows higher data rates. The FPC (flexible printed circuit) is usually 0.2 mm thick, with a width of about 10 mm to 15 mm and a length of 20 mm to 30 mm, depending on the connector placement. The connector is typically a 0.5 mm pitch FPC connector, with 30 to 40 pins. For example, the DM-TFT34-485 uses a 30-pin connector with a 0.5 mm pitch, requiring a mating connector like the FH12-30S-0.5SH. The electrical specifications include a logic voltage of 1.8 V to 3.3 V, with a typical power consumption of 150 mW to 250 mW for the display alone, and 300 mW to 400 mW with the backlight at full brightness.
Viewing angles are another dimension to consider. These displays typically use IPS (in-plane switching) or TN (twisted nematic) technology. For the DM-TFT34-485, it uses IPS, offering 80 degrees in all directions (left, right, up, down), which is crucial for dashboards or control panels where the screen might be viewed from an angle. Contrast ratio is usually 800:1 to 1000:1, with a response time of 20 ms to 30 ms (typical for IPS). The color gamut is around 60% to 70% of the NTSC standard, which is fine for industrial applications but not for high-end color grading. The display supports 16.7 million colors (8-bit per channel) via the MIPI interface, but some controllers may limit to 262k colors (6-bit per channel) if using a lower-end driver IC like the ILI9488 or ST7789. However, the DM-TFT34-485 uses a custom driver IC (likely the RM67162 or similar) that supports 8-bit color depth and a 480x480 resolution natively.
Mechanical mounting is straightforward. The display has four mounting holes, typically 2.0 mm in diameter, located at the corners of the module. The hole spacing is about 68.0 mm from center to center horizontally and vertically. These holes are designed for M2 screws, with a recommended torque of 0.1 Nm to 0.2 Nm to avoid cracking the glass. The display also has a bezel width of about 2.5 mm to 3.0 mm around the active area, which is standard for this size. The total weight of the module is around 15 grams to 20 grams, including the FPC and backlight. For touch panel integration, a capacitive touch panel (CTP) is often added, which increases the thickness by 0.8 mm to 1.2 mm and adds about 5 grams to 10 grams. The CTP typically uses an ITO (indium tin oxide) layer with a multi-touch capability of up to 5 points, using a controller like the FT6336 or GT911. The CTP’s dimensions are usually the same as the display module, 74.80 mm x 74.80 mm, with a transparent area of 70.08 mm x 70.08 mm.
Optical performance data is worth detailing. The luminance uniformity across the active area is typically 80% to 85%, meaning the corners are slightly dimmer than the center. This is measured with a 9-point or 13-point test pattern. The chromaticity coordinates (CIE 1931) for the white point are usually around x=0.31, y=0.33, which is close to the D65 standard. The color temperature is around 6500 K to 7000 K. The gamma curve is set to 2.2, which is the standard for sRGB. The display’s refresh rate is 60 Hz, but some MIPI controllers can support 90 Hz or 120 Hz if the pixel clock is increased. For a 480x480 resolution at 60 Hz, the pixel clock is about 16.5 MHz (assuming a blanking overhead of 10% to 15%). The MIPI DSI data rate is typically 200 Mbps to 400 Mbps per lane, with four lanes giving a total of 800 Mbps to 1.6 Gbps, which is more than enough for 480x480 at 60 Hz.
Environmental specs are also important for industrial use. The operating temperature range is usually -20°C to +70°C, with a storage range of -30°C to +80°C. The display can handle humidity up to 90% RH at 60°C, non-condensing. The shock resistance is rated for 50 G for 11 ms, and vibration is 10 G from 10 Hz to 200 Hz. These specs make it suitable for handheld devices, medical equipment, or automotive dashboards (though not for direct sunlight exposure without a higher brightness backlight). The backlight LED lifetime is typically 20,000 to 30,000 hours, which is about 2.5 to 3.5 years of continuous use. However, if the display is used in a dimmer environment, the backlight can be driven at lower current, extending the lifetime to 50,000 hours.
For comparison, here’s a table of key dimensions for the DM-TFT34-485 and a generic 3.4 inch 480x480 display:
| Parameter | DM-TFT34-485 (Specific) | Generic 3.4 inch 480x480 |
|---|---|---|
| Module width (mm) | 74.80 | 74.80 ± 0.2 |
| Module height (mm) | 74.80 | 74.80 ± 0.2 |
| Active area width (mm) | 69.12 | 69.12 ± 0.1 |
| Active area height (mm) | 69.12 | 69.12 ± 0.1 |
| Viewing area width (mm) | 70.08 | 70.08 ± 0.1 |
| Viewing area height (mm) | 70.08 | 70.08 ± 0.1 |
| Module thickness (mm) | 2.5 (without touch) | 2.5 to 3.0 |
| Pixel pitch (mm) | 0.144 | 0.144 |
| PPI (pixels per inch) | 277 | 277 |
| Connector pins | 30 | 30 to 40 |
| Interface type | MIPI DSI (4-lane) | MIPI or RGB |
| Backlight LEDs | 6 to 8 in series | 6 to 8 |
| Brightness (cd/m²) | 350 to 400 | 300 to 500 |
| Weight (grams) | 18 | 15 to 20 |
Now, let’s talk about the controller and driver IC. The DM-TFT34-485 uses a specific driver IC that supports 480x480 resolution natively, which is less common than 480x272 or 480x800. The IC is usually a single-chip solution that includes the gate driver, source driver, and timing controller. The IC’s package is typically a COG (chip-on-glass) or COF (chip-on-flex) type, which reduces the module size. The IC’s operating voltage is 1.8 V for the logic and 2.8 V to 3.3 V for the analog. The IC also supports various display modes like full-on, full-off, and sleep mode, which can reduce power consumption to less than 1 mW. The IC’s memory is usually SRAM-based, with a frame buffer of 480x480x24 bits, which is about 691 KB. This is why the display can operate without constant data refreshes, but it still requires a continuous clock for the MIPI interface.
For integration with microcontrollers, the MIPI interface requires a host controller that supports MIPI DSI, like the STM32F769 or i.MX RT series. The display’s FPC has a pinout that includes power (VDD, VDDI), ground, MIPI data lanes (D0P, D0N, D1P, D1N, etc.), clock lane (CLKP, CLKN), and a reset pin. The reset pin is active low and must be held low for at least 10 ms after power-up to initialize the driver IC. The backlight is controlled separately via a PWM pin, typically 100 Hz to 1 kHz, with a duty cycle of 0% to 100%. The display also includes a TE (tearing effect) pin, which can be used to synchronize the frame rate with the host, preventing screen tearing. The TE pin outputs a pulse at the start of each frame, which is useful for video playback.
Mechanical tolerances are tight. The module’s overall dimensions have a tolerance of ±0.2 mm, which is standard for glass-based displays. The active area alignment is within ±0.1 mm of the center of the module. The FPC’s bend radius is usually 3 mm to 5 mm, so it can be folded behind the display if needed, but repeated bending can damage the copper traces. The display’s surface is covered with a polarizer that is anti-glare (matte) or glossy, depending on the application. The DM-TFT34-485 uses an anti-glare polarizer, which reduces reflections but slightly lowers contrast. The polarizer’s hardness is 3H to 4H, which is scratch-resistant but not bulletproof. For touch panels, the CTP’s surface is usually glass with a hardness of 6H to 7H, which is more durable.
Optical characteristics in different lighting conditions are worth noting. At 400 cd/m², the display is readable in indoor office lighting (500 lux) but becomes washed out in direct sunlight (100,000 lux). For outdoor use, a brightness of 800 cd/m² is recommended, which can be achieved by using a higher current backlight or a different LED configuration. The contrast ratio drops from 1000:1 in a dark room to about 200:1 under 10,000 lux ambient light, due to reflection. The display’s reflectivity is about 5% to 8% for the anti-glare version, which is typical for TFT LCDs. If you need outdoor readability, consider a bonded CTP with an optical clear adhesive (OCA) that reduces the air gap, lowering reflectivity to 2% to 3%.
Power consumption details are critical for battery-powered devices. At 60 Hz, with the backlight at 50% brightness (200 cd/m²), the display draws about 100 mA at 3.3 V, which is 330 mW. The driver IC draws about 20 mA, and the backlight draws about 80 mA. In sleep mode, the display draws less than 1 mA, but the backlight must be turned off separately. The display’s power-up sequence requires VDD to be applied first, then the MIPI clock, and then the reset pin must be released. This sequence takes about 50 ms to 100 ms. The display can also be turned off by pulling the reset pin low, which puts the IC into a low-power state.
For the 3.4 inch 480x480 tft lcd display from DisplayModule, the datasheet provides specific electrical characteristics. The input voltage for VDD is 2.5 V to 3.6 V, with a typical of 3.0 V. The VDDI (interface voltage) is 1.65 V to 3.6 V, with a typical of 1.8 V. The backlight forward voltage is 21 V to 24 V for 6 LEDs in series, with a current of 20 mA. The display’s MIPI DSI interface supports a maximum data rate of 500 Mbps per lane, which is more than enough for 480x480 at 60 Hz. The display also supports a command mode where the host can send commands to set parameters like gamma, brightness, and contrast. The IC’s register set includes over 100 registers for fine-tuning the display.
Finally, let’s address the cost and availability. The DM-TFT34-485 is priced around $15 to $25 per unit in small quantities, with discounts for bulk orders. It’s available from DisplayModule and distributors like Mouser or Digi-Key. The lead time is usually 4 to 6 weeks for custom orders, but standard versions are in stock. The display is RoHS compliant and has a CE marking. For prototyping, you can also get a breakout board with a 30-pin FPC connector and a voltage regulator, which simplifies wiring. The breakout board adds about $5 to $10 to the cost. The display’s lifespan is typically 5 to 7 years under normal use, but the backlight may need replacement after 20,000 hours. The display is also compatible with various operating systems like Linux, Android, and Windows via a MIPI to HDMI converter, but that adds latency and complexity.