Case Study: LED Lighting Technology for a Medical Device

Posted by on Oct 26, 2023

How We Create Smooth, Uniform Light Guides Using LED Lighting Technology & Selective Illumination

In emergency situations, clear instruction and direction are essential to saving lives. This is especially true during a medical emergency when every second counts. Selective illumination with LED lighting technology helps provide guidance in these tense situations.

A medical device manufacturer needed to leverage the power of LED lighting technology to create a new life-saving defibrillator that anyone could use. Read on to learn how our team collaborated with this customer to overcome challenges and craft a custom solution that enhanced the overall design and function with selective illumination and smooth, uniform lighting.


The main goal of the device’s lighting was to illustrate the steps users needed to take during each stage of the defibrillation process. LED lighting technology would allow for simple icons to instruct users. To make each stage of care distinct, the customer requested colored LED lights in different zones that would be illuminated one at a time. This requires precise illumination without backlight bleed. Creating a smooth, uniform light guide within the constraints of the product design was a challenge our team was eager to solve.


Throughout the lifecycle of the product, complex engineering challenges were presented. The first was to create a uniform light appearance on the defibrillator instruction panel. One consequence of a non-uniform light guide is a dim display. This has aesthetic drawbacks, but more importantly, it wasn’t functional for every user. Without selective, uniform lighting, a user with eyesight issues might not interpret the defibrillator directions correctly.

In order to be effective, the solution required that each of the zones be very close together and illuminated by a different color of LED without backlight bleed or bright spots in front of the LEDs while ensuring the lighting is bright enough for ambient lighting conditions.


From the start, our team knew selective illumination would be the path forward to light the defibrillator instruction panel. Selective illumination incorporates light-blocking properties into the design, resulting in reduced light bleed. Additionally, it allows the features to operate independently of each other.

For this defibrillator, our engineers used dual shot injection molding, a type of selective illumination, to achieve smooth, uniform lighting. This is similar to overmolding but streamlines the process. Instead of two separate injection mold tools where one supplies the light guide material and the other supplies the white light-blocking material, dual shot accomplishes this in a single injection mold tool.

We paired dual shot injection molding with multiple LEDs to achieve maximum brightness. High brightness is often desirable, but with the light from multiple LEDs in a small area, a bright spot can form near the center of the light and look non-uniform.

To counteract this, our team applied an optical pattern that is less dense in areas of high brightness and higher density in areas further away from the LEDs. We also added a diffuser (or optical) film to further soften the light and increase uniformity by smoothing out the dim spots between LEDs. Our team used optical simulations to determine LED placement and shapes of the animation cutouts on the light guide.

Our prototype methodology was crucial to providing a solution to this customer. The customer was able to feel the product in their hands and review every detail in person. We created prototypes in-house for this application using our laser-etched and cut prototype process because the 2D geometry was simple to execute. Our prototype capability range allows us to offer customers prototypes hand-crafted in-house or the potential to create thousands in one of our ISO- and IATF-certified manufacturing facilities.


The light guide prototype phase of our proven process allowed our customer to review our design. Prototypes were delivered on schedule and quick corrections were made based on customer feedback, highlighting our ability to listen and deliver. Our team’s flexibility and focus on meeting our customer’s needs helped them achieve the results they set out to create.

Custom LED Lighting Technology: Your Solution to Complex, Unique Illumination Needs

Smooth, uniform lighting is desired for many lighting applications. When it’s a necessity for a medical device, it’s crucial to lean on a trusted light guide design manufacturer who has the expertise to deliver a specialized and custom solution.

From our refined, industry-leading optical pattern and LED lighting technology to our experienced engineering team, we’re proud to offer illumination solutions that exceed expectations. Connect with our team to begin your light guide design project with us.

We bet you have a bright idea.

Let’s see how GLT can help make it a reality.

For even more information about GLT, view our company presentation at the link below.