What is the aspect ratio of a 1.33 inch Sharp Memory TFT?
The aspect ratio of a 1.33 inch Sharp Memory TFT is exactly 1:1. This is a square display, with a resolution of 128x128 pixels, meaning the width and height are identical in both pixel count and physical dimensions. The active area measures 23.99mm x 23.99mm, giving you a perfect square shape. This is a critical detail for engineers and designers because a 1:1 aspect ratio is rare in modern displays, which are typically rectangular (like 16:9 or 4:3). The square format makes this display ideal for applications where symmetrical layouts or circular UI elements are needed, such as smartwatches, medical devices, or industrial control panels. You can find the exact specifications for this 1.33 inch sharp memory tft display on the product page.
The 1:1 aspect ratio is not just a mathematical curiosity; it directly impacts how you design your user interface and hardware enclosure. With a 128x128 pixel matrix, each pixel is square, measuring 0.1875mm x 0.1875mm. This gives you a pixel density of about 135 pixels per inch (PPI). For comparison, a typical smartphone display might have a 19.5:9 aspect ratio with a much higher PPI, but the 1:1 ratio here is deliberately chosen for applications where a circular or square bezel is required. The Sharp Memory TFT technology also means the display retains its image even when power is removed, which is a huge advantage for always-on interfaces. You don't need to refresh the screen constantly, saving battery life in portable devices.
Let's break down the physical dimensions. The display module itself, including the glass and the FPC (flexible printed circuit), measures 32.5mm x 36.5mm x 1.4mm. The active area is 23.99mm x 23.99mm, which is the part that actually lights up. The bezel around the active area is about 4.25mm on the left and right, and about 6.25mm on the top and bottom. This bezel is necessary for the driver IC and the bonding pads. The 1:1 aspect ratio means your UI elements must be designed for a square canvas. If you try to display a standard 16:9 video, you'll get black bars on the top and bottom, or you'll have to crop the image. For data visualization, like a circular gauge or a square meter, the 1:1 ratio is perfect. You can center a circular dial without any wasted space.
The Sharp Memory TFT technology is a specific type of LCD that uses a memory-in-pixel (MIP) architecture. This is different from standard TFT displays. In a standard TFT, each pixel is refreshed continuously, even if the image doesn't change. In a Sharp Memory TFT, each pixel has its own memory cell. Once you write the image data to the display, the pixels hold that state indefinitely without any further power draw. This is why the display is called "memory" TFT. The 1:1 aspect ratio is a direct result of the 128x128 resolution, which is a common resolution for MIP displays because it's a power of two (2^7). This makes addressing the pixels efficient for the controller. The display uses a 4-wire SPI interface, which is simple to implement with microcontrollers like Arduino or STM32.
From a practical standpoint, the 1:1 aspect ratio also affects the viewing angle. The Sharp Memory TFT has a viewing angle of 160 degrees in both horizontal and vertical directions. Because the display is square, the viewing cone is symmetric. This is important for devices that are viewed from multiple angles, like a wristwatch. If you rotate your wrist, the image doesn't distort as much as it would on a rectangular display with a non-uniform viewing angle. The contrast ratio is typically 10:1, which is lower than a high-end OLED, but it's more than sufficient for monochrome or low-color applications. The display supports 64 colors, which is enough for simple icons, text, and basic graphics. The 1:1 aspect ratio ensures that any circular or square elements you draw are perfectly aligned with the pixel grid.
Let's compare this with other common display sizes to highlight the uniqueness of the 1:1 ratio. A 1.44 inch TFT display often has a 128x128 resolution as well, but the physical size might be slightly different. A 1.44 inch display typically has a diagonal of 1.44 inches, but the aspect ratio can vary. Some 1.44 inch displays are 128x128 (1:1), while others are 128x160 (5:4). The 1.33 inch Sharp Memory TFT is specifically designed with a 1:1 ratio to fit into compact, square enclosures. The 1.33 inch diagonal measurement is the hypotenuse of the square active area. Since the active area is 23.99mm x 23.99mm, the diagonal is sqrt(23.99^2 + 23.99^2) = 33.93mm, which is about 1.336 inches. So the 1.33 inch specification is accurate.
Here is a detailed table of the key specifications:
| Parameter | Value | Unit |
|---|---|---|
| Diagonal Size | 1.33 | inches |
| Aspect Ratio | 1:1 | - |
| Resolution | 128 x 128 | pixels |
| Active Area (W x H) | 23.99 x 23.99 | mm |
| Pixel Pitch | 0.1875 x 0.1875 | mm |
| Pixel Density | 135 | PPI |
| Module Size (W x H x T) | 32.5 x 36.5 x 1.4 | mm |
| Interface | 4-wire SPI | - |
| Color Depth | 64 colors | - |
| Viewing Angle | 160 (H) x 160 (V) | degrees |
| Contrast Ratio | 10:1 | - |
| Power Consumption (standby) | 0.01 | mW |
| Power Consumption (active) | 0.5 | mW |
| Operating Temperature | -20 to +70 | °C |
The 1:1 aspect ratio also influences the mechanical design of the device. If you're designing a smartwatch, for example, the square display allows for a symmetrical bezel. You can center the display in a round or square case. The 1.33 inch size is small enough to fit into a compact housing, but large enough to display meaningful information. The 128x128 resolution gives you 16,384 pixels. For a monochrome interface, you can display about 8 lines of text with 16 characters per line, depending on the font size. For a color interface, you can show simple icons and gauges. The 1:1 ratio is particularly useful for displaying a circular clock face. You can draw a circle that exactly fits the square, and the bezel of the display becomes the frame of the clock. This is a common use case for this display.
The Sharp Memory TFT also has a unique characteristic: its refresh rate is not like a standard LCD. You don't need to refresh the display at 60Hz. Instead, you only update the pixels that change. This is because the memory-in-pixel technology stores the state of each pixel. The 1:1 aspect ratio doesn't affect the refresh behavior, but it does affect how you calculate the data for the update. For a 128x128 square, you need to send 128 rows of data, each row being 128 pixels. With 64 colors, each pixel requires 6 bits of color information. So each row is 128 pixels * 6 bits = 768 bits. You send this data via SPI, and the display updates the corresponding row. Because the display is square, the row and column drivers are symmetric, which simplifies the controller design.
From a software perspective, the 1:1 aspect ratio means your coordinate system is square. If you're using a graphics library like Adafruit GFX or u8g2, you set the display width and height both to 128. This is straightforward. You can draw a circle with a radius of 64 pixels, and it will be perfectly centered. You can draw a square with sides of 64 pixels, and it will be centered. The 1:1 ratio eliminates the need for aspect ratio correction in your drawing functions. This is a significant advantage for developers who are not experienced with display programming. You don't have to worry about scaling or cropping. You just treat the display as a square canvas.
The 1.33 inch Sharp Memory TFT is also known for its low power consumption. The standby power is 0.01 mW, and the active power is 0.5 mW. This is orders of magnitude lower than a standard TFT display, which might consume 50 mW or more. The 1:1 aspect ratio doesn't directly affect power consumption, but the small size and the memory-in-pixel technology do. For battery-powered devices, this display is a game-changer. You can leave the display showing static information, like a clock or a status indicator, without draining the battery. The 1:1 ratio is also ideal for segmented displays, where you might have a circular or square layout. The 128x128 resolution is high enough for smooth curves and fine details, but low enough that the controller doesn't need a lot of processing power.
Let's talk about the physical interface. The display has a 12-pin FPC connector. The pins include VCC, GND, SCL, SDA, CS, DC, RES, and backlight control. The SPI interface runs at up to 10 MHz. The 1:1 aspect ratio means that the data for each row is the same length. This makes the SPI communication predictable. You can use DMA (direct memory access) to send the data without CPU intervention. The display also has a built-in controller, the Sharp LS013B7DH03, which handles the memory-in-pixel operations. The controller is designed to work with the 128x128 resolution and the 1:1 aspect ratio. You don't need an external frame buffer. The controller stores the image data in the pixel memory.
Another important detail is the backlight. The display has a white LED backlight with a typical brightness of 350 cd/m². The backlight is separate from the LCD panel. The 1:1 aspect ratio of the active area means the backlight is also square. This is efficient because the light is evenly distributed across the square area. The backlight consumes about 20 mA at 3.3V, which is 66 mW. This is the main power draw when the backlight is on. However, because the Sharp Memory TFT retains the image, you can turn off the backlight and still see the display in ambient light. The reflective mode is actually quite readable. The 1:1 ratio is also good for reflective displays because the square shape matches the natural shape of many optical elements.
In terms of durability, the display is made of glass with a thickness of 0.7mm. The module thickness is 1.4mm, which includes the glass, the polarizer, and the FPC. The 1:1 aspect ratio means the glass is square, which is mechanically stable. Square glass panels are less prone to cracking than rectangular ones because the stress distribution is more uniform. The display also has a hard coating for scratch resistance. The operating temperature range is -20°C to +70°C, which is typical for industrial applications. The 1:1 aspect ratio doesn't affect the temperature range, but it does affect how you mount the display. You can use a square bezel or a square cutout in your enclosure. The mounting holes are typically on the FPC, not on the glass.
For developers, the 1:1 aspect ratio means you can use standard libraries without modification. The Adafruit Sharp Memory Display library, for example, works directly with this display. You just set the width and height to 128. The library handles the SPI communication and the memory-in-pixel protocol. The 1:1 ratio is also compatible with the Sharp Memory Display's "partial update" feature. You can update only a portion of the screen, which is useful for animations or changing data. The partial update is efficient because the display is square. You can update a 64x64 square in the center of the screen, and the rest of the screen remains unchanged. This is much faster than updating the entire 128x128 display.
From a cost perspective, the 1.33 inch Sharp Memory TFT is relatively affordable compared to other low-power displays. The 1:1 aspect ratio is a standard configuration for this type of display, so it's mass-produced. The cost is typically around $10 to $15 per unit, depending on the quantity. The 1:1 ratio also means that the display is compatible with standard square LCD modules. If you're designing a product that requires a square display, this is one of the most cost-effective options available. The 128x128 resolution is a sweet spot for many applications. It's high enough for detailed graphics, but low enough to keep the cost down.
One more thing: the 1:1 aspect ratio is also relevant for the display's gamma correction. The Sharp Memory TFT has a built-in gamma curve that is optimized for the 128x128 resolution. The 1:1 ratio means that the gamma correction is symmetric. This is important for color accuracy. The display supports 64 colors, which are generated by combining 6 bits of red, green, and blue. The 1:1 ratio doesn't affect the color representation, but it does affect how you map colors to the pixel grid. For a square display, you can use a square color palette. This is a minor detail, but it's important for professional applications where color accuracy is critical.
I should also mention the interface voltage. The display operates at 3.3V logic, but it can tolerate 5V on the control lines if you use a level shifter. The 1:1 aspect ratio doesn't affect the voltage requirements, but it does affect the current draw. The display draws about 0.5 mA in active mode, which is very low. The 1:1 ratio means that the display is efficient in terms of area. The active area is 5.76 square centimeters, and the power consumption is 0.5 mW. That's about 0.087 mW per square centimeter. This is extremely efficient. For comparison, a standard TFT display might consume 10 mW per square centimeter. The Sharp Memory TFT is about 100 times more efficient.
Let's talk about the viewing angle in more detail. The 1:1 aspect ratio means that the viewing angle is the same in all directions. The display has a 160-degree viewing angle in both horizontal and vertical directions. This is because the liquid crystal layer is aligned in a way that provides uniform contrast from all angles. The 1:1 ratio is particularly beneficial for applications where the display is viewed from different angles, like a wearable device. If you rotate your wrist, the image doesn't distort. The 160-degree viewing angle is sufficient for most applications. If you need a wider viewing angle, you might need an IPS display, but the Sharp Memory TFT is not an IPS panel. It's a TN (twisted nematic) panel with a special memory layer.
The 1:1 aspect ratio is also important for the display's refresh rate. The Sharp Memory TFT has a typical refresh rate of 60 Hz, but you don't need to refresh it continuously. The memory-in-pixel technology means that the display only needs to be updated when the image changes. The 1:1 ratio doesn't affect the refresh rate, but it does affect the data transfer rate. For a 128x128 display, you need to transfer 128 rows of data. Each row is 128 pixels. With a 10 MHz SPI clock, you can transfer a full frame in about 10 milliseconds. This is fast enough for most applications. The 1:1 ratio ensures that the data transfer is symmetric, which simplifies the timing.
From a mechanical perspective, the 1:1 aspect ratio also affects the FPC (flexible printed circuit) design. The FPC is 12.5mm wide and extends from the bottom of the display. The 1:1 ratio means that the FPC is centered on the bottom edge. This is a standard design for square displays. The FPC has a pitch of 0.5mm and is reinforced with a stiffener. The 1:1 ratio doesn't affect the FPC design, but it does affect how you route the FPC in your enclosure. You can bend the FPC to the back of the display, or you can route it to the side. The