What is the size of a 1.3 inch 240x240 IPS panel?

The physical size of a 1.3 inch 240x240 IPS panel is defined by its diagonal measurement of 1.3 inches, which translates to approximately 33.02 millimeters. However, the actual viewable area, module dimensions, and pixel density vary significantly based on the specific manufacturer and design. For a standard 1.3 inch 240x240 ips display, the active area typically measures 23.4mm by 23.4mm, resulting in a square aspect ratio of 1:1. This square format is unusual for small displays, which are often rectangular, but it’s chosen for applications like smartwatches, digital gauges, or circular UI emulation where a square grid simplifies graphics rendering. The total module size, including the driver IC, flex cable, and bezel, usually ranges from 27.5mm to 28.5mm in width and height, with a thickness of about 1.2mm to 1.5mm, depending on whether it includes a backlight or touch overlay.

Pixel density is a critical metric here. With 240 pixels across a 23.4mm width, the pixel pitch calculates to 0.0975mm per pixel, yielding a PPI (pixels per inch) of roughly 260. That’s significantly higher than a typical 2.8-inch TFT display at 240x320 resolution, which might have a PPI around 143. For comparison, a 1.3 inch 240x240 IPS panel achieves a pixel density similar to early smartphone Retina displays—like the iPhone 4 at 326 PPI—but on a much smaller scale. This high density means individual pixels are nearly invisible at normal viewing distances of 20-30cm, making it suitable for displaying crisp text, icons, or even small fonts at 8-12pt size without anti-aliasing artifacts. The IPS technology itself ensures wide viewing angles, typically 80 degrees in all directions, with contrast ratios around 800:1 to 1000:1, and brightness levels between 250 and 400 nits, depending on the backlight LED configuration.

Let’s break down the dimensions in a table for clarity, based on common specifications from manufacturers like BOE, ILITEK, or Shenzhen-based suppliers. These numbers are averaged from datasheets for 1.3-inch 240x240 IPS modules with SPI interface, which is the most common interface for this size due to its low pin count (typically 4-wire or 6-wire SPI).

Now, the 1.3-inch size is not arbitrary. It’s a sweet spot for wearable devices because it fits within the typical watch face diameter of 38-42mm, leaving room for bezels and housing. For example, a smartwatch with a 1.3-inch display would have a screen-to-body ratio of about 60-70%, depending on the case design. The 240x240 resolution at this size means each pixel is 97.5 microns—smaller than a human hair (which averages 70-100 microns). This fine pitch allows for anti-aliased graphics, but the driver IC must handle a 240x240 frame buffer, which is 57,600 pixels. With 16-bit color (RGB565), each frame requires 115,200 bytes of RAM. Most SPI-based controllers like the ST7789 or ILI9341 (though ILI9341 is more common for larger sizes) have built-in GRAM of 240x240x18-bit, which is 129,600 bytes, so they can handle 262K colors. But the actual color depth supported depends on the driver; for a 1.3 inch 240x240 IPS panel, the ST7789V is frequently used, which supports 12-bit, 16-bit, and 18-bit color modes via SPI, with a maximum clock speed of 10-20MHz for 4-wire SPI.

From a mechanical perspective, the mounting holes or alignment tabs are rarely present on these small modules. Instead, they rely on the flex cable’s stiffener (usually a 0.2mm thick polyimide or PET layer) for soldering to a PCB. The flex cable length is typically 15-25mm, with a 0.5mm pitch connector, often a 6-pin or 8-pin FPC. The backlight is a single white LED, driven at 20-25mA, with a forward voltage of 3.0-3.2V. The total power consumption for the display plus backlight is around 40-60mW at full brightness, which is critical for battery-powered devices. If you’re integrating this into a product, you need to account for the active area’s offset from the module edge. Many datasheets show the active area centered, but some have a 1mm offset to one side to accommodate the driver IC’s bond pad. For instance, the driver IC is often placed on the glass itself using COG (Chip-on-Glass) technology, which adds about 2-3mm to the module’s footprint on one side. So the actual module dimensions might be 27.7mm x 30.2mm if the driver is on a short side.

Let’s compare this with other common small display sizes to give context. A 1.54-inch 240x240 IPS panel, for example, has a diagonal of 39.1mm and an active area of 27.6mm x 27.6mm, giving a PPI of 220. That’s lower density, but the larger size is better for touch interfaces. A 1.28-inch 240x240 round display (often used in circular smartwatches) has a diagonal of 32.5mm but a circular active area, which reduces the usable pixel count. The 1.3-inch square format is actually more efficient for rectangular UIs, as you don’t waste pixels on corners. In terms of weight, a bare 1.3 inch 240x240 IPS panel without backlight weighs about 3-4 grams, and with the backlight and flex cable, it’s around 5-6 grams. This is light enough for drone telemetry displays or handheld gaming microconsoles.

Data from real-world testing shows that the response time of these IPS panels is typically 25-30ms (gray-to-gray), which is acceptable for static images or slow updates, but not for video at 60fps. The refresh rate via SPI is limited by the bus speed. At 10MHz SPI clock, transferring a 240x240 16-bit frame takes about 9.2ms (240*240*16 bits / 10,000,000 bits per second = 0.09216 seconds, actually 92ms—correction: 240*240 = 57,600 pixels, 16 bits each = 921,600 bits, at 10MHz = 0.09216 seconds, or 92ms. So the maximum frame rate is about 10.8 fps. For 60fps, you’d need a 60MHz SPI clock, which is possible with some MCUs like ESP32 or STM32H7, but the panel’s internal timing might limit it to 30fps due to the display controller’s row scan rate. The ST7789V, for instance, has a typical row scan time of 1.5 microseconds, so 240 rows take 360 microseconds, plus blanking, resulting in a maximum refresh of about 2.5kHz theoretically, but the SPI input is the bottleneck.

Thermal characteristics are also important. The operating temperature range for a 1.3 inch 240x240 IPS panel is usually -20°C to +70°C, with storage from -30°C to +80°C. The IPS liquid crystal material has a clearing point above 100°C, but the polarizers degrade above 70°C. In cold environments, the response time can increase to 50-80ms at -10°C, causing ghosting. The backlight LED has a lifespan of 20,000-30,000 hours at 20mA, but if you drive it at 25mA, it drops to 15,000 hours. For industrial applications, you might want to derate the current to 18mA for longevity.

When it comes to optical performance, the 1.3 inch 240x240 IPS panel typically has a transmissive mode, meaning it relies entirely on the backlight. The contrast ratio is measured with the backlight on, and it’s usually 800:1 in a dark room. Under sunlight, the reflectivity of the polarizer causes glare, so an anti-glare coating or a higher brightness (400 nits) is needed for outdoor readability. Some variants include a circular polarizer to reduce reflections, but that adds cost. The color gamut is typically 50-60% NTSC, which is fine for icons and text but not for photo-realistic images. The viewing angle is where IPS shines: at 80 degrees from normal, the contrast ratio drops to 100:1, but the color shift is minimal—less than 30% change in chromaticity coordinates. In contrast, a TN panel at the same angle would show a 80% color shift and negative contrast.

From a connectivity standpoint, the SPI interface uses four signals: CS (chip select), DC (data/command), SCLK (serial clock), and MOSI (master out slave in). Some modules also have a RESET pin and a backlight enable pin. The supply voltage is 2.8V to 3.3V for the logic, and the backlight requires 3.0-3.3V. The current draw for the logic is about 1-2mA, and for the backlight, 20mA, so total 22mA at 3.3V equals 72.6mW. If you use a boost converter from a 3.7V lithium battery, the efficiency loss adds about 10-15%.

Another dimension to consider is the pixel arrangement. The 240x240 resolution means each row has 240 pixels, and the driver IC scans rows sequentially. The ST7789V uses a 240x240x18-bit GRAM, but the data is written in 16-bit chunks via SPI. The memory is organized as 240 columns and 240 rows, but the driver can be configured for landscape or portrait orientation by swapping the row and column start addresses. The physical orientation of the display is usually defined by the location of the flex cable. Most modules have the flex exiting from the bottom edge, but some have it on the left or right for specific layouts. The active area is centered on the glass, but the glass itself is larger—typically 30mm x 30mm for a 1.3-inch module, with a 1mm border on each side. The glass thickness is 0.5mm to 0.7mm, and the polarizer adds another 0.1mm.

For mounting, you can use double-sided adhesive tape (like 3M 467MP) on the back of the module, but make sure the tape doesn’t cover the driver IC or the flex cable bond area. The module’s back is usually a metal shield or a plastic frame, but some are just the bare glass with a stiffener. If you’re using a touch overlay, the total thickness increases to 2.5-3mm, and the touch controller (like FT6206) adds another I2C interface. The touch panel is typically capacitive with a 2mm air gap or optical bonding. Optical bonding reduces reflections but adds cost and is harder to repair.

The 1.3 inch 240x240 IPS panel is also used in digital microscopes, where the high PPI allows for fine detail. For example, at 200x magnification, a 1.3-inch display shows a 1.2mm x 1.2mm area of the sample, with each pixel representing 5 microns. That’s useful for PCB inspection or biological slides. In medical devices, the small size fits into handheld pulse oximeters or glucose meters, where the square format matches the UI layout for numeric readouts. The SPI interface is compatible with low-power MCUs like the STM32L0 series, which can run at 32MHz and drive the display at 10fps while consuming 10mA total.

Finally, let’s discuss the cost and availability. A 1.3 inch 240x240 IPS panel in quantities of 100-500 units costs around $3-5 per piece, depending on the backlight type (white or RGB) and whether it includes a touch panel. The SPI interface is the cheapest option, as it uses fewer pins than parallel RGB or MIPI. For prototyping, you can find breakout boards with a 1.3-inch display and an ST7789 driver for about $8-10 on distributor sites. The module is RoHS compliant and lead-free, with a storage life of 6 months in a dry environment. The glass is made from soda-lime or borosilicate, with a hardness of 6-7 on the Mohs scale, so it’s scratch-resistant but not shatterproof. For rugged applications, you can add a 0.5mm thick cover glass with an adhesive layer.