Straight up: a 240x320 resolution on a 2.4 inch screen gives you a pixel density of roughly 166 pixels per inch (PPI). That’s calculated by taking the diagonal resolution in pixels (sqrt(240² + 320²) = 400 pixels) and dividing by the diagonal size in inches (2.4). So you get 400 / 2.4 = 166.67 PPI. This is a common spec for small embedded displays, like those found in IoT devices, handheld gaming consoles, or old-school feature phones. At this size, individual pixels are visible if you hold it close—around 0.15 mm per pixel—but for most practical uses, it’s sharp enough for text, icons, and basic graphics. The aspect ratio is 3:4 (portrait) or 4:3 (landscape), which is a bit squarer than modern smartphones. If you’re looking for a specific module, the 2.4 inch 240x320 ips display is a solid choice for projects needing color accuracy and wide viewing angles.
Let’s break down what that resolution actually means in real-world terms. A 240x320 display has 76,800 total pixels. Compare that to a 1080p screen (2,073,600 pixels) and it’s about 27 times less detail. But on a 2.4 inch panel, those pixels are packed tightly enough that you can read 8-point font without squinting, as long as the contrast is decent. The pixel pitch—the distance between the center of two adjacent pixels—is about 0.152 mm. That’s roughly the thickness of two sheets of paper. For reference, a 24-inch 1080p monitor has a pixel pitch of 0.274 mm, so the 2.4 inch screen actually has smaller pixels, which means sharper images at the cost of overall size. The trade-off is that you’re not going to watch movies on it; it’s built for data display, UI controls, or simple animations.
Now, let’s talk about the screen technology. The 240x320 resolution is often paired with IPS (In-Plane Switching) or TFT (Thin-Film Transistor) LCD panels. IPS gives you 178-degree viewing angles, meaning you can look at it from the side without color shifting. TFT is cheaper but has narrower angles—usually around 120 degrees horizontal. On a 2.4 inch screen, the difference is noticeable if you’re mounting it in a dashboard or a wearable. The color depth is typically 16-bit (65,536 colors) or 18-bit (262,144 colors) for these small displays. That’s enough for gradient backgrounds and simple icons, but not for photo-realistic images. The brightness ranges from 250 to 400 nits, with 300 nits being common. At 400 nits, it’s readable outdoors in shade, but direct sunlight will wash it out without a polarizer.
Let’s get into the numbers behind the interface. Most 240x320 2.4 inch screens use a parallel interface (like 8-bit or 16-bit MCU) or SPI (Serial Peripheral Interface). SPI is slower—typically 10-20 MHz—but uses fewer pins (4-6). For a 240x320 display, SPI can push a full frame refresh at about 15-30 frames per second (fps) depending on the controller. Parallel interfaces can hit 60 fps easily, but they need 8 to 16 data lines plus control pins. The controller chip is usually an ILI9341 or ST7789, which are well-documented and have built-in RAM for framebuffer. The ILI9341 has 172,800 bytes of RAM for the 240x320 resolution (using 18-bit color), so it can store a full frame without external memory. That’s important for microcontrollers like an ESP32 or STM32, which might have limited RAM themselves.
Power consumption is another practical angle. A 2.4 inch 240x320 IPS display with backlight on draws about 50-80 mA at 3.3V. That’s 165-264 mW. If you’re running on a 2000 mAh battery, you’d get about 25-40 hours of continuous use. Turning off the backlight drops it to 5-10 mA. For battery-powered devices, you can use PWM to dim the backlight and extend runtime. The display itself (without backlight) only consumes 1-2 mA for the LCD driver. So the backlight is the main power hog. If you’re building a sensor reader that updates every 10 seconds, you can put the display to sleep and wake it up, cutting average power to under 10 mW.
Let’s compare this resolution to other common small screen sizes. Here’s a table showing pixel density and total pixels for different diagonal sizes at 240x320:
| Screen Diagonal (inches) | Resolution (pixels) | PPI | Total Pixels | Pixel Pitch (mm) |
|---|---|---|---|---|
| 1.8 | 240x320 | 222 | 76,800 | 0.114 |
| 2.0 | 240x320 | 200 | 76,800 | 0.127 |
| 2.4 | 240x320 | 166 | 76,800 | 0.152 |
| 2.8 | 240x320 | 143 | 76,800 | 0.178 |
| 3.2 | 240x320 | 125 | 76,800 | 0.203 |
As you can see, as the screen gets bigger, the pixel density drops. At 2.4 inches, 166 PPI is a sweet spot—it’s high enough to avoid obvious pixelation but low enough to keep the cost down. For comparison, a 2.8 inch screen at the same resolution looks noticeably grainier, with a pixel pitch of 0.178 mm. That’s why many industrial devices stick to 2.4 inches for this resolution. The 3.2 inch version is often used for low-cost MP3 players, but you can see individual pixels from a foot away.
Let’s talk about the physical dimensions. A 2.4 inch screen with 240x320 resolution typically has an active area of about 36.72 mm x 48.96 mm. That’s 1.45 x 1.93 inches. The module itself (including the PCB and connector) is usually around 42 mm x 60 mm. The thickness is about 2.5 mm for the glass, plus another 1-2 mm for the backlight and PCB. So the total module is around 4-5 mm thick. That’s thin enough to fit into a credit card-sized enclosure. The viewing area is slightly larger than the active area because of the bezel—usually 2-3 mm on each side. So if you’re designing a case, you need to account for that.
Now, let’s get into the color and contrast specifics. These displays typically have a contrast ratio of 500:1 to 1000:1 for IPS, and 300:1 to 500:1 for standard TFT. At 500:1, black levels are around 0.6 cd/m² if the brightness is 300 cd/m². That means dark scenes in a UI will look grayish in a dark room, but fine in normal lighting. The response time is usually 10-20 ms for IPS, which is fine for static menus but can cause ghosting for fast animations. For a 2.4 inch screen, that’s rarely an issue because you’re not playing action games on it. The color gamut is typically 60-70% of NTSC, which means colors are somewhat muted compared to a smartphone screen. Reds and greens are decent, but blues might look a bit washed out.
Let’s look at the interface timing. If you’re using SPI at 20 MHz, transferring a full 240x320 frame with 16-bit color (2 bytes per pixel) takes 240 * 320 * 2 = 153,600 bytes. At 20 MHz, that’s 153,600 / (20,000,000 / 8) = 0.06144 seconds, or about 61 ms. But you also need to send commands and wait for the display to process, so real-world frame rate is around 15-20 fps. With parallel interface at 8-bit, you can transfer 1 byte per clock cycle at 10 MHz, so 153,600 / (10,000,000 / 8) = 0.12288 seconds, or 122 ms—slower. But 16-bit parallel at 10 MHz gives 153,600 / (10,000,000 / 16) = 0.24576 seconds, or 245 ms. Wait, that math is wrong. Let me correct: 16-bit parallel sends 2 bytes per clock, so at 10 MHz, you send 20 MB/s. 153,600 bytes / 20,000,000 bytes/s = 0.00768 seconds, or 7.68 ms. That’s 130 fps theoretical. In practice, you get about 60 fps due to overhead. So parallel is faster but uses more pins.
For developers, the 240x320 resolution on a 2.4 inch screen is a common target for GUIs like LVGL, uGFX, or emWin. The framebuffer size is 153,600 bytes for 16-bit color, which fits in the RAM of most microcontrollers (STM32F4 has 192 KB, ESP32 has 520 KB). You can also use partial updates to reduce memory usage. For example, if you’re only updating a 100x100 area, you only need 20,000 bytes. That’s useful for battery-powered devices where you want to minimize power and memory. The display controller supports windowing, so you can define a rectangle and only send data for that area. That’s how you can do smooth animations without a massive framebuffer.
Let’s talk about the touch interface. Many 2.4 inch 240x320 displays come with a resistive touch panel. Resistive touch has a resolution of about 4096x4096 points, but it’s analog, so the actual accuracy depends on the ADC. Typically, you get about 1% accuracy, which means you can distinguish about 240 touch points across the screen. That’s fine for button presses, but not for handwriting. Capacitive touch is rare at this size because it’s more expensive and the small screen doesn’t justify it. The touch controller is usually an XPT2046, which communicates over SPI. It adds about 2-3 ms to the response time. If you’re using a GUI, you need to calibrate the touch coordinates to the display coordinates, which involves a linear mapping. The typical calibration error is about 2-3 pixels, which is acceptable for UI elements that are at least 20 pixels wide.
Now, let’s look at the environmental specs. These displays are usually rated for 0-50°C operating temperature, which covers most indoor and outdoor use. Storage temperature is -20 to 70°C. The glass is typically 0.5 mm thick, and the polarizer is on top. If you’re using it in a humid environment, you need to seal the edges because moisture can get between the glass and the backlight, causing fogging. The backlight is usually 4 white LEDs in series, with a forward voltage of about 3.2V each. So the total backlight voltage is around 12.8V, but it’s driven by a boost converter from 3.3V. The LED lifetime is typically 20,000 hours, which is about 2.3 years of continuous use. After that, the brightness drops to 50%.
Let’s compare this to a 2.4 inch 320x480 display (HVGA). That would have a PPI of 231, which is noticeably sharper. But the cost is higher—about 30-50% more—and the interface speed needs to be faster because you’re pushing 153,600 bytes per frame (same as 240x320 at 16-bit) but with more pixels. Wait, 320x480 at 16-bit is 307,200 bytes, twice the data. So the frame rate drops. That’s why many designers stick with 240x320 for this size—it’s a balanced trade-off between clarity and performance. The 240x320 resolution is also a standard QVGA (Quarter VGA), which means software libraries have built-in support for it. You can find drivers for almost any microcontroller.
Let’s talk about the actual pixel layout. In a 240x320 display, the pixels are arranged in a stripe pattern: red, green, blue subpixels in a row. Each subpixel is about 0.05 mm wide. The fill factor (the percentage of the area covered by the subpixels) is about 70-80%, meaning there’s a small gap between them. That’s why you can see a grid if you look closely with a magnifier. The color filter is made of dye, not pigment, so it can fade over time if exposed to UV. The response time of the liquid crystals is about 10 ms for rising and 15 ms for falling, so the total transition time is 25 ms. That’s fast enough for 40 fps without ghosting. But if you’re driving it at 60 fps, you might see a slight blur on moving objects.
For a practical application, let’s say you’re building a smart thermostat. The 2.4 inch 240x320 display can show a temperature graph, setpoint, and fan status. The text size for a 12-point font is about 16 pixels tall, so you can fit 20 lines of text. That’s enough for a settings menu. The touch interface lets you tap buttons that are 30x30 pixels, which is about 4.5 mm square—easy to hit with a finger. The power consumption at 50% brightness is about 40 mA, so a 2000 mAh battery lasts 50 hours. If you’re using a Wi-Fi module, the display is the second biggest power draw after the radio. So you can optimize by turning off the display when not in use.
Let’s get into the connector details. The 2.4 inch 240x320 display usually has a 24-pin or 34-pin FPC (Flexible Printed Circuit) connector. The pitch is 0.5 mm, which is tiny. You need a matching connector on your PCB, like a FH12-24S-0.5SH. The pinout is standard: power (3.3V), ground, backlight (LED+ and LED-), SPI lines (SCLK, MOSI, MISO, CS, DC, RST), and touch lines (if present). The MISO line is optional because you don’t usually read data from the display. The CS and DC pins are critical for SPI communication. The backlight is usually controlled by a separate MOSFET or a PWM pin from the microcontroller. The current for the backlight is about 20 mA per LED, so 80 mA total for 4 LEDs. That’s why you need a driver circuit, not just a GPIO pin.
Let’s talk about the manufacturing process. These displays are made using a-Si (amorphous silicon) TFT technology, which is cheap but has lower electron mobility than LTPS (Low-Temperature Poly-Silicon). That’s why the response time is slower. The glass substrate is 0.5 mm thick, and the backlight is a light guide plate with a diffuser film. The total thickness of the module is about 3 mm, including the backlight. The bezel is made of metal or plastic, and it’s glued to the glass with double-sided tape. The FPC is attached using anisotropic conductive film (ACF), which is a type of glue that conducts electricity in one direction. That’s why you can’t repair a broken FPC—you have to replace the whole module.
Now, let’s look at the cost. A 2.4 inch 240x320 IPS display module costs between $5 and $15 in single quantities, depending on the brand and features. For example, a module with a touch panel and a breakout board costs about $12. In bulk (1000 units), the price drops to $3-5. The display panel itself is about 60% of the cost, the backlight is 20%, and the FPC is 10%. The touch panel adds another 10-20%. For a project, you can buy a bare panel and design your own PCB, but the breakout board is easier for prototyping. The ILI9341 controller is the most common, and it’s supported by Arduino, Raspberry Pi, and ESP32 libraries. So you can get a prototype running in a few hours.
Let’s talk about the optical performance. The viewing angle of an IPS panel is 178 degrees in all directions, which means you can see the image from the side without color shift. The contrast ratio is 800:1 typical. The brightness is 300 cd/m², which is about 100 nits less than a typical smartphone. The color gamut is 60% NTSC, so colors are not as vivid. The gamma curve is usually 2.2, which matches most video standards. The response time is 10 ms (gray to gray), which is fine for static images. The refresh rate is 60 Hz, but the SPI interface limits the actual frame rate to 20-30 fps. If you’re using a parallel interface, you can get 60 fps. The display supports 8-bit, 16-bit, and 18-bit color modes. The 18-bit mode