What is the pixel pitch of a 2.4 inch 240x320 TFT display?

The pixel pitch of a standard 2.4 inch 240x320 TFT display is approximately 0.1525 millimeters (152.5 micrometers) per pixel. This figure is derived from the physical dimensions of the active display area, which typically measures 36.72 millimeters in width and 48.96 millimeters in height for a 2.4-inch diagonal. Dividing the width by 240 horizontal pixels gives 36.72 / 240 = 0.153 mm per pixel, and the height divided by 320 pixels yields 48.96 / 320 = 0.153 mm as well. Some manufacturers might round this to 0.15 mm, but the precise value depends on the exact bezel and glass design. For a 2.4 inch 240x320 tft display, the pixel pitch directly impacts image sharpness, viewing distance, and overall visual clarity, making it a critical parameter for embedded systems, handheld devices, and industrial interfaces.

To understand pixel pitch, you need to grasp the relationship between resolution and physical size. The 240x320 resolution means 240 columns and 320 rows of pixels. The diagonal of 2.4 inches (about 61 mm) is the standard measurement for the glass size, but the active area is slightly smaller. In most datasheets for this form factor, the active area is 36.72 mm x 48.96 mm, giving a pixel pitch of 0.1525 mm. This is consistent across many suppliers like Winstar, Newhaven, and DisplayModule, though minor variations exist due to manufacturing tolerances. For example, some modules use a 0.15 mm pitch, which is within 2% of the calculated value. The pixel pitch determines the pixel density, which for this display is about 166 pixels per inch (PPI). That’s calculated by dividing 1 inch (25.4 mm) by 0.1525 mm, yielding roughly 166.6 PPI. This density is moderate, suitable for text and basic graphics but not for high-DPI applications like smartphone screens.

Let’s break down the math with a table for clarity. The pixel pitch is essentially the center-to-center distance between adjacent pixels. For a 2.4-inch 240x320 TFT, the active area dimensions are standardized. Here’s a comparison of common small TFT displays:

Display Size (Diagonal)	Resolution	Active Area (mm)	Pixel Pitch (mm)	PPI
2.4 inch	240x320	36.72 x 48.96	0.1525	166.6
2.8 inch	240x320	43.20 x 57.60	0.1800	141.1
3.2 inch	240x320	48.60 x 64.80	0.2025	125.5
1.8 inch	128x160	28.03 x 35.04	0.2190	116.0

This table shows that the 2.4-inch display has the smallest pixel pitch among these common sizes, meaning it packs more pixels per inch. The 0.1525 mm pitch is actually quite fine for a TFT of this class. Compare it to a 3.2-inch display with the same resolution, which has a larger pitch of 0.2025 mm and lower PPI. The smaller pitch on the 2.4-inch screen means individual pixels are less visible to the naked eye at typical viewing distances of 20-30 cm. However, it’s still not as sharp as a modern smartphone, which often exceeds 300 PPI. For industrial or embedded use, this pitch is acceptable for displaying sensor data, menus, or simple icons, but you might notice pixelation if you hold it close.

Now let’s talk about how pixel pitch affects real-world performance. The 0.1525 mm value directly influences the minimum feature size that can be rendered. For example, a single pixel line on this display is about 0.15 mm wide. If you draw a 1-pixel-wide vertical line, it will be barely visible, but a 2-pixel line (0.3 mm) is more distinct. This matters for applications like barcode readers or medical devices where precise alignment is needed. The contrast ratio and viewing angles also interact with pixel pitch. Typical TFTs in this size have a contrast ratio of 300:1 to 500:1 and viewing angles of 60 degrees left/right and 40 degrees top/bottom. With a 0.1525 mm pitch, the brightness uniformity across the panel is decent, but you might see slight color shifts at extreme angles due to the pixel structure. The aperture ratio—the percentage of each pixel that actually emits light—is usually around 60-70% for these displays, which affects overall brightness. A typical backlight brightness is 250-350 cd/m², so the perceived brightness per pixel is adequate for indoor use.

Another key factor is the interface type. The 2.4-inch 240x320 TFT often uses SPI, MCU 8-bit, or RGB parallel interfaces. The pixel pitch doesn’t change with the interface, but the driving method does. For SPI, the data is sent serially, which can limit refresh rates. With a 0.1525 mm pitch, the total number of pixels is 240 x 320 = 76,800. If you’re using SPI at 20 MHz, each pixel requires 16 bits of color data (RGB565), so the theoretical maximum frame rate is around 20 MHz / (76,800 x 16) ≈ 16.3 frames per second, but overhead reduces it to about 10-12 fps. This is fine for static images but not for video. MCU parallel interfaces can push 30-60 fps, which is better for animations. The pixel pitch itself doesn’t limit frame rate, but the physical size does affect how fast you can scan the rows. The row scanning time is proportional to the number of rows (320), and the pixel pitch determines the row height. A 0.1525 mm pitch means each row is 0.1525 mm tall, so the total active area height is 48.96 mm. The gate driver IC needs to charge each row’s pixels sequentially, and the RC time constant of the pixel capacitance (typically 0.1-0.5 pF per pixel) combined with the row resistance affects the charging speed. For a 2.4-inch display, the row resistance is low because the lines are short, so charging is fast. This is why these displays can achieve decent refresh rates even with simple controllers.

Let’s look at the manufacturing tolerances. The pixel pitch of 0.1525 mm is a nominal value, but actual production can vary by ±0.005 mm due to photolithography alignment and etching processes. This variation is usually negligible for visual applications, but for optical systems that require precise pixel alignment, like in a microscope eyepiece or a projection system, this tolerance matters. The glass substrate thickness is typically 0.55 mm or 0.7 mm, and the polarizer adds another 0.1-0.2 mm. The overall module thickness is about 2.0-2.5 mm including the backlight. The pixel pitch also affects the parallax effect when using a touch panel. If you add a resistive or capacitive touch overlay, the distance between the touch surface and the pixel plane can cause offset errors, especially at the edges. With a 0.1525 mm pitch, the parallax error is about 0.3-0.5 mm for a typical touch panel thickness of 1.0 mm, which is acceptable for finger touch but might be noticeable for stylus input.

Now, consider the color depth. Most 2.4-inch 240x320 TFTs support 16-bit color (RGB565), meaning 65,536 colors. The pixel pitch doesn’t affect color reproduction directly, but it does influence the subpixel arrangement. Standard TFTs use an RGB stripe pattern where each pixel consists of three subpixels: red, green, and blue. With a 0.1525 mm pitch, each subpixel is about 0.0508 mm wide (0.1525 / 3). This is the same as the pitch divided by three, assuming equal width. The subpixel height is the same as the pixel height, 0.1525 mm. So each subpixel is a rectangle roughly 0.05 mm x 0.15 mm. This aspect ratio affects how text is rendered. For example, anti-aliasing algorithms use subpixel rendering to improve perceived sharpness, but the elongated subpixels can cause color fringing if not handled properly. In practice, many embedded systems use simple bitmap fonts that don’t leverage subpixel rendering, so the pixel pitch is the main factor in legibility. A 0.1525 mm pitch means that a 10-point font (about 3.5 mm tall) will be about 23 pixels high, which is readable for most users. But a 6-point font (2.1 mm) would be only 14 pixels high, making it hard to read without magnification.

There’s also the question of viewing distance. The ideal viewing distance for a display is roughly 1.5 to 2 times the diagonal, so for a 2.4-inch screen, that’s about 3.6 to 4.8 inches (9-12 cm). At this distance, the human eye can resolve details down to about 0.1 mm at 20/20 vision. Since the pixel pitch is 0.1525 mm, you’ll see individual pixels if you look closely, but at normal arm’s length (30-40 cm), the pixels blend together. For applications like a smartwatch or a handheld meter, this is fine. But if you’re using it as a viewfinder for a camera, you might want a higher PPI. The 166 PPI is comparable to older smartphones like the iPhone 3GS (163 PPI) but far below modern Retina displays (326 PPI). So the pixel pitch is a trade-off between cost and clarity. Cheaper modules might use a slightly larger active area, pushing the pitch to 0.16 mm, while premium ones might have tighter tolerances. Always check the datasheet for the exact active area dimensions, as some manufacturers might use a 36.50 x 48.80 mm area, giving a pitch of 0.1521 mm.

Let’s get into the electrical side. The pixel pitch affects the capacitance of the pixel electrodes. Each pixel has a storage capacitor that holds the charge during the frame refresh. The capacitance is proportional to the pixel area, which is the pitch squared. For a 0.1525 mm pitch, the pixel area is about 0.0233 mm² (0.1525 x 0.1525). The typical capacitance per pixel is around 0.2-0.4 pF, depending on the liquid crystal material and cell gap. The total panel capacitance is 76,800 pixels times that, which is about 15-30 nF. This is important for the driver IC’s power consumption. The driver needs to charge and discharge these capacitors at the refresh rate, so a larger pitch would mean higher capacitance and more power draw. But since this pitch is small, the power consumption is moderate. The backlight is the main power hog, typically drawing 50-100 mA at 3.3V for standard LEDs. The pixel pitch also influences the liquid crystal response time. Typical response times for TN TFTs are 10-20 ms (rise) and 15-30 ms (fall), which is fine for static images but might cause ghosting for fast-moving objects. The pitch doesn’t directly affect response time, but the cell gap (usually 3-5 µm) combined with the pixel size does. A smaller pitch might require a thinner cell gap to maintain the same electric field, which can improve response time slightly. However, for most 2.4-inch displays, the response time is dominated by the liquid crystal material, not the pitch.

Another angle is the optical stack. The pixel pitch is determined by the TFT array mask, which is created using photolithography. The mask has a resolution of about 0.5-1 µm, so the 0.1525 mm pitch is easily achievable. The color filter substrate has a similar pitch, with RGB color resists aligned to the TFT pixels. The alignment tolerance is typically ±5 µm, which is much smaller than the pitch, so color bleeding is minimal. The black matrix (BM) between pixels is usually 5-10 µm wide, which reduces the aperture ratio. For a 0.1525 mm pitch, the BM width is about 5% of the pitch, so the effective light-emitting area is about 90% of the pixel area. This is standard for these displays. The viewing angle is affected by the pixel structure, not the pitch directly, but the pitch determines the angular resolution of the display. At a 60-degree viewing angle, the effective pixel size appears smaller due to foreshortening, which can reduce perceived sharpness. This is why some users report that text looks blurry at extreme angles, but it’s more about the LCD mode (TN, IPS, or VA) than the pitch. Most 2.4-inch TFTs use TN mode, which has poor viewing angles, so the pixel pitch is less of a factor than the panel technology.

Let’s look at some real-world numbers. The pixel pitch of 0.1525 mm corresponds to a dot pitch of 0.1525 mm, which is the same as the pixel pitch for monochrome displays but for color, it’s the same because we’re talking about full pixels. Some datasheets list the dot pitch as 0.153 mm, which is a rounded value. For example, the Winstar WF24HTIBCDNGA# has a dot pitch of 0.153 mm, and the active area is 36.72 x 48.96 mm. The Newhaven NHD-2.4-240320CF-CSXN#F also uses 0.153 mm. These are consistent. The pixel pitch is also used to calculate the resolution per inch, which is 166.6 PPI. This is a standard metric for comparing displays. For reference, a 2.4-inch 240x320 display has a PPI of 166.6, while a 2.8-inch with the same resolution has 141.1 PPI, and a 3.2-inch has 125.5 PPI. So the 2.4-inch is the sharpest among these. But if you compare it to a 1.5-inch 128x128 display, which has a pitch of 0.2 mm and 127 PPI, the 2.4-inch is clearly better. The pixel pitch is a direct indicator of how fine the details can be. For example, to display a 1 mm wide line, you need about 6.6 pixels (1 / 0.1525). So a 1 mm line will be rendered as 7 pixels, which is acceptable. But a 0.5 mm line would require 3.3 pixels, which might look jagged.

Now, let’s talk about the display’s application in embedded systems. The pixel pitch determines the size of the GUI elements. If you’re designing a UI for a 2.4-inch screen, you need to consider that a 10x10 pixel button is about 1.5 mm x 1.5 mm, which is too small for finger touch. A typical finger touch target is 8-10 mm, so you’d need about 52-65 pixels per side. That’s a large portion of the screen. So the pixel pitch forces you to use large icons and simple layouts. For a 2.4-inch display, the usable area is about 36.72 x 48.96 mm, which is roughly the size of a credit card. With a 0.1525 mm pitch, you can fit about 240 characters of text at 8x8 font size (each character is 8x8 pixels, so 1.22 mm tall). That’s 30 characters per row and 40 rows, which is a lot of text. But readability suffers at small font sizes. So the pixel pitch is a trade-off between information density and legibility. For industrial panels, this is often acceptable because the user is trained to read small text. But for consumer products, you’d want a larger display or higher resolution.

Another important aspect is the pixel pitch’s effect on the display’s fill factor. The fill factor is the ratio of the light-emitting area to the total pixel area. For a TFT, the pixel area includes the TFT switch, storage capacitor, and bus lines, which are opaque. The fill factor for a 2.4-inch 240x320 TFT is typically 60-70%. This means that about 30-40% of the pixel area is blocked by the circuitry. With a 0.1525 mm pitch, the opaque area is about 0.007-0.009 mm² per pixel, leaving 0.014-0.016 mm² for light transmission. This affects the brightness and contrast. A lower fill factor means you need a brighter backlight to achieve the same perceived brightness. For a 2.4-inch display, the backlight is usually 4-6 LEDs in series, providing 250-350 cd/m². The fill factor also influences the viewing angle because the opaque areas can cause shadowing at extreme angles. This is more pronounced in TN panels, where the liquid crystal molecules tilt in a specific direction, and the opaque areas can block light at certain angles. The pixel pitch doesn’t directly cause this