What is the resolution of a 1.33 inch Sharp Memory TFT display?
The resolution of a 1.33 inch Sharp Memory TFT display is 128 x 128 pixels. This is a fixed, non-negotiable specification for this specific panel, often referred to as the 1.33 inch sharp memory tft display. It’s not a high-resolution display by modern smartphone standards, but that’s entirely by design. The 128x128 resolution, combined with the 1.33 inch diagonal, gives you a pixel density of roughly 135 pixels per inch (PPI). To put that in perspective, a standard 24-inch 1080p monitor sits around 92 PPI, so this little panel actually packs more detail per inch than a typical desktop screen. The trade-off is that it’s monochrome—specifically, it uses a 1-bit per pixel memory system, meaning each pixel is either on or off, with no grayscale. This is a critical detail for anyone evaluating this display for a project.
The 128x128 resolution is not arbitrary. It’s tied directly to the Sharp Memory LCD technology, which uses a static memory element at each pixel. Unlike traditional TFT-LCDs that need constant refreshing to maintain an image, this panel holds the pixel state in its internal SRAM. The 128x128 grid means there are 16,384 individual memory cells, each controlling one pixel. When you write data to the display, you’re essentially updating the entire frame buffer, and the panel retains that image without any power draw to the LCD itself. This is why the resolution is relatively low—it’s a deliberate trade-off to keep the memory footprint small and the power consumption absurdly low. Typical current draw for this display is under 50 microamps when idle, and it spikes to around 200 microamps during a full-screen update, which takes about 1.5 milliseconds per line at 3.3V.
Let’s break down the physical dimensions. The 1.33 inch diagonal is measured from corner to corner of the active area. The active area itself is 26.86 mm x 26.86 mm, which is a perfect square. That’s important because the 128x128 resolution is also square, so each pixel is a perfect square with a pitch of 0.21 mm. This is a key spec for optical alignment in applications like viewfinders or wearable displays. The overall module size, including the bezel and the flexible flat cable (FFC), is 30.9 mm x 33.6 mm x 1.3 mm. The thickness is just 1.3 mm, which makes it one of the thinnest TFT panels on the market. The FFC is 15-pin, with a 0.5 mm pitch, and it’s about 30 mm long. These dimensions are critical for mechanical integration—you’re not going to fit this into a standard 0.1-inch header breadboard without an adapter.
Now, let’s talk about the interface. The display uses a serial peripheral interface (SPI) with a dedicated command set. The resolution of 128x128 directly affects the data transfer requirements. Each pixel is 1 bit, so a full frame is 16,384 bits, or 2,048 bytes. At a typical SPI clock speed of 10 MHz, you can update the entire display in about 1.6 milliseconds, ignoring overhead. That’s fast enough for simple animations, but don’t expect video. The refresh rate is limited by the memory update time, not the pixel response time. The LCD response time itself is around 10 milliseconds, which is typical for a passive matrix. But because the memory holds the state, you don’t need to refresh the panel at 60 Hz. You can update it once and leave it for hours, and the image will stay perfectly stable with zero power consumption to the display driver.
One of the most misunderstood aspects of this display is the contrast ratio. Sharp markets this as having a “high contrast ratio” of 10:1. That’s not a typo—it’s 10:1, not 1000:1 like an OLED. But for a monochrome reflective display, that’s actually excellent. The reflective nature means it uses ambient light to illuminate the pixels, so in bright sunlight, the contrast can appear much higher because the black pixels absorb light and the white pixels reflect it. The typical reflectivity is around 20%, which is comparable to e-paper. The viewing angle is rated at 180 degrees, which is true for a reflective display because there’s no backlight to wash out. The color is black and white, with no intermediate shades. This is a hard limit of the 1-bit memory system.
Let’s compare this to other small displays in the same category. Here’s a quick table of common 1-inch class displays:
| Display Type | Diagonal (inches) | Resolution | Pixel Density (PPI) | Bit Depth | Power (idle) |
|---|---|---|---|---|---|
| Sharp Memory LCD | 1.33 | 128x128 | 135 | 1-bit | < 50 µA |
| OLED (e.g., SSD1306) | 1.3 | 128x64 | 110 | 1-bit (mono) | ~20 mA |
| TFT (e.g., ILI9341) | 1.8 | 128x160 | 114 | 16-bit color | ~30 mA |
| E-paper (e.g., Pervasive) | 1.54 | 200x200 | 184 | 1-bit | 0 µA (static) |
Notice that the Sharp Memory LCD has a lower pixel density than the e-paper display, but it’s much faster. The e-paper takes about 2 seconds to update a full frame, while the Sharp display updates in milliseconds. The OLED is brighter but uses 400 times more power when idle. The TFT color display uses even more power and requires constant refresh. This is where the Sharp Memory LCD’s resolution and power trade-off makes sense for battery-powered devices that need a persistent display without draining the battery. Think of a smart badge, a digital price tag, or a remote control screen that shows a static icon for days.
The driving electronics are also worth discussing. The display uses a Sharp proprietary driver IC, the LS013B7DH03, which is embedded on the glass. The IC supports a 128x128 resolution natively, and it has a built-in oscillator for generating the internal timing. The SPI interface is 3.3V logic, but it’s 5V tolerant on the input pins, which is a nice touch for hobbyists using Arduino or Raspberry Pi. The command set is minimal: you send a command to set the column and page addresses, then send the pixel data. The memory is organized as 128 columns by 128 rows, but the data is sent in 8-bit bytes, so each byte represents 8 pixels in a row. This means you need to send 16 bytes per row, and 128 rows, for a total of 2,048 bytes per frame. The driver supports partial updates, but the entire memory must be written sequentially—you can’t update individual pixels without rewriting the entire row.
One practical consideration is the pixel structure. The 128x128 resolution on a 1.33 inch diagonal gives a pixel pitch of 0.21 mm. That’s fine for text at a typical viewing distance of 30 cm, where a 6-point font would be readable. But if you’re trying to display complex graphics, the lack of grayscale means you’ll need to rely on dithering. Dithering patterns work well because the pixel density is high enough to fool the eye at a distance. For example, a 2x2 Bayer matrix can simulate 4 shades of gray, but it effectively reduces the resolution to 64x64 for that pattern. This is a common technique used in e-paper and monochrome OLEDs, and it works here too. The refresh rate for a dithered image is still the same, because the memory is still 1-bit per pixel—you’re just controlling the pattern of black and white pixels.
Temperature range is another factor. The Sharp Memory LCD operates from -20°C to +70°C, which is typical for consumer-grade LCDs. But the memory retention is affected by temperature. At -20°C, the pixel response time increases to about 30 milliseconds, and the contrast ratio drops slightly. At +70°C, the response time decreases to 5 milliseconds, but the contrast ratio remains stable. The memory itself is static, so it doesn’t lose data when the temperature changes, but the liquid crystal material does change viscosity. This is important for outdoor applications like ski goggles or car dashboards. The display is also sensitive to UV light, so direct sunlight exposure over years can degrade the polarizer. But for indoor use, it’s fine.
Let’s look at the optical characteristics in more detail. The reflectivity of 20% means that under typical office lighting of 500 lux, the white pixels will have a luminance of about 100 cd/m². That’s comparable to a newspaper, which has a reflectivity of around 60% but is not backlit. The black pixels have a reflectivity of about 2%, giving a contrast ratio of 10:1. In direct sunlight (100,000 lux), the white luminance jumps to 20,000 cd/m², which is actually brighter than a typical smartphone screen at maximum brightness (around 600 cd/m²). This is why reflective displays are preferred for outdoor readability. The trade-off is that in dim light, the display is hard to read without a front light. Some modules integrate a front light, but the standard Sharp Memory LCD does not.
The 128x128 resolution also has implications for the driver IC’s power consumption. The LS013B7DH03 has a typical operating current of 50 µA when the display is static, but that’s just the IC itself. The LCD panel draws no current when the image is static. When you update the display, the current spikes to 200 µA for the duration of the update. If you update the display once per second, the average current is about 50 µA + (200 µA * 1.6 ms / 1000 ms) = 50.32 µA. That’s negligible. If you update it 100 times per second, the average current is 50 µA + (200 µA * 1.6 ms / 10 ms) = 82 µA. Still low. This makes it ideal for wearable devices where a coin cell battery needs to last months. For comparison, a typical OLED with the same resolution would draw 20 mA continuously, which would drain a CR2032 battery in about 10 hours.
One more detail: the display supports a “VCOM” signal that is used to invert the pixel polarity to prevent image sticking. This is a common issue with static LCDs. The driver IC automatically handles the VCOM inversion at a frequency of about 60 Hz, but you can disable it if you’re updating the display frequently. The inversion is transparent to the user, but it does draw a small amount of current. The total power consumption with VCOM enabled is about 5 µA higher than without. This is a spec that’s often overlooked in datasheets, but it matters for ultra-low-power designs.
In terms of mechanical integration, the 1.33 inch diagonal and 128x128 resolution mean that the display is best suited for square or near-square applications. The active area is 26.86 mm on each side, so if you’re designing a bezel, you need to account for the 0.3 mm border around the active area. The module has four mounting holes, but they’re not threaded—they’re just alignment holes for a plastic frame. The FFC is fragile, so you’ll need a connector that locks. The recommended connector is a 15-pin 0.5 mm pitch FPC connector, like the Hirose FH12 series. The pinout is standard, with power, ground, SPI lines, and a few control signals. The display requires a 3.3V supply, but the logic level can be 1.8V to 3.6V, which is useful for low-voltage microcontrollers.
Finally, let’s address the elephant in the room: why not use a higher resolution? The 128x128 resolution is a sweet spot for this technology. Sharp makes Memory LCDs in other sizes, like 1.28 inch with 128x128, 1.35 inch with 128x128, and even a 2.7 inch with 400x240. But the 1.33 inch version is the most common because it balances pixel density, power, and cost. The 128x128 resolution on a 1.33 inch diagonal gives a pixel pitch that’s large enough to be easily manufactured with high yield, small enough to be readable, and square enough to be versatile. The driving electronics are simple, the memory footprint is small, and the power consumption is unmatched. If you need more resolution, you’re better off with a color TFT or an e-paper display, but you’ll pay for it in power or speed.