Custom LCDs as a Drop-in Replacement
If the display on our computers and smartphones gets damaged or starts acting weird, it troubles us to some extent and hinders our daily activities. However, since these displays are commercially available, we can simply go to a servicing center and repair or replace them. But what if the model is discontinued? What if the LCD is on a manufacturing machine, an infusion pump, or radiation detection equipment? You may think you need to redesign the product to adapt to a different LCD and do a recertification for the updated product with FDA, UL, or any other certification body. However, depending on the situation, you may have another option.
Thanks to LCD technology’s flexibility and practicality, you may be able to order a custom LCD module as a drop-in replacement.
This article will explore how a custom LCD module can potentially replace your original display and mimic its original properties.
Understanding the Original LCD
Let’s start by understanding the original display on your hardware. You must dive into its technical properties to replicate it properly and create a custom one.
Module Size and Form Factor
The original LCD’s physical dimensions are referred to as the module size, which includes the thickness, width, and height of the native module. The drop-in LCD must fit within that spot since the LCDs are attached to a machine within specific borders. Some LCD technologies are easily customizable in terms of module size and can be made to match the original
Next, note the form factors of that LCD module. The display may have trimmed corners or a unique shape. The aim is to ensure the drop-in custom LCD precisely fits in the space designated for the original module. Any deviation could cause problems with installation or appearance.
Viewing Area (Active Display Area)
The viewing area is the area of the screen that displays content. This is where your characters, shapes, or pixels form visuals. On TVs and monitors, the viewing area is kept as wide as possible, sometimes eliminating border trims. It does not include bezels or non-display regions.
So, you need to calculate the original LCD’s active display area and note any borders or bezels surrounding it. To ensure consistency, the viewing area of the customized LCD should be equal to that of the original. However, you may need to make further adjustments depending on the design constraints.
Resolution or Character Count
This is the next vital step in your planning. Depending on the machine, you may have one of the following LCDs: a graphic or a character-based display.
Graphic Display Drop-Ins
Graphic displays are easily found on most gadgets today. Whether it’s a television, computer monitor, smartphone, smartwatch, or tablet, they all use pixel-based graphic displays. Their characteristics depend on how many pixels are in the horizontal and vertical directions.
For example, a 1080p display consists of 1920 columns and 1080 rows of pixels. Each pixel comprises three color subpixels (red, green, and blue). Therefore, in a 1080p display, there are 1920 x 3 = 5760 sub-pixels. Each subpixel comprises a liquid crystal, netting 5760 liquid crystals in a full HD display.
So, the more resolution you require, the higher the pixel density will be. But you will need more powerful drivers as well.
Character Based Drop-Ins
These LCDs have predetermined shapes, such as characters, numbers, punctuations, etc. They’re also known as alphanumeric screens that primarily focus on character count. So, rather than pixel density, integrating the required number of shapes gets priority.
Interface Type
All LCD modules function through the integrated circuit (IC) or driver. To clarify, an LCD IC is a microprocessor that bridges the device hardware and the display. It powers the display, takes information through firmware, and translates it so the display can portray the data. So, depending on the application and screen type, the IC can be very different.
Determine the controller of the current device (e.g., microcontroller, FPGA). Ensure the custom LCD’s interface type (parallel, SPI, or I2C) corresponds to the controller’s capabilities. Also, handle any software modifications required to interface with the new LCD.
Backlighting
The application, the frequency of use, and your budget will determine which backlighting technology you should use. LEDs are a popular option because of their longevity and energy efficiency. But you can also choose CCFLs as they’re brighter and affordable.
It’s also important to consider the uniformity of light dispersion, the required intensity for clear vision in different lighting circumstances, and the effect on the LCD’s power consumption. The mechanical and electrical design must also consider the selected backlighting approach (edge-lit or array) to achieve native-like illumination.
Dropping In the Custom LCD
Understanding and recording the finer technical details of your LCD may be complex on your own. Drivers, attached modules, and other hardware dependencies on the display can be problematic for an average user to understand. That’s why we offer professional assistance with designing and manufacturing customized LCD modules at Focus LCDs.
Once the technical details are confirmed, we quote your custom order. After payment, we’ll provide the drop-in LCD module spec sheet so you can check and approve the customized design. At this stage, you can cross-check your existing LCD module with our spec sheet to ensure everything is in place or make suggestions.
The next step is prototyping. We will prepare a prototype to test on your existing device. Carefully verify the prototype’s functionality. Check the display content, touch responsiveness, brightness of the pixels, location and changing of the alphanumeric characters, and other features from the previous display. We also suggest that you assess visibility under different lighting and working conditions. Make sure to check the power consumption and heat dissipation as well. Once the prototype is approved, we produce mass production quantities based on the approved prototype design. Overall, the replacement process can be daunting, however in most cases, the process is simpler than redesigning the product to adapt to another off-the-shelf LCD.