Expert Testimony Sharpens Focus in the Signify Lepro Patent Trial

The third witness to testify in the Signify vs Lepro patent trial was Dr. David S. Rickett, who appeared on direct examination by Jeremy Oczek on behalf of the plaintiffs. Rickett holds a Ph.D. in power electronics from Harvard and has taught at MIT, Harvard, and NC State. Over the past decade, he has consulted extensively across the lighting and electronics industries.

The court accepted Rickett as an expert witness without objection, but I don’t think he expected that aluminum foil would be part of the discussion.

Rickett testified that Signify retained him to analyze six Lepro smart lighting products. His task was straightforward: determine whether those products infringed Signify’s patents. To do so, he conducted hands-on teardowns, performed direct testing, and reviewed evaluations completed by independent laboratories. Based on that work, Rickett concluded that all six products infringed the asserted patent claims.

Claim-by-Claim Breakdown of the ’320 Patent

To explain his conclusions, Rickett guided the jury through a structured, claim-by-claim analysis. He used a detailed chart to divide the patent language into individual elements, labeled a through e. Then, step by step, he mapped each element to physical features found in the accused products.

Physical Demonstrations Reinforce Infringement Claims

Rickett did not rely on charts alone. Instead, he brought several Lepro smart bulbs into the courtroom, including units that he had already disassembled. By pointing out the internal layout, he showed how the heat sink formed part of the outer enclosure and how the internal components aligned with the patent claims.

As a result, the jury could connect abstract patent language to real hardware. These demonstrations played a key role in grounding the Signify vs Lepro patent trial in tangible evidence rather than theory.

Signify vs Lepro Patent Trial: Why the ’577 Patent Matters Technically

After establishing infringement, Rickett turned to the technical importance of the ’577 Patent. He explained that LED lighting presents a persistent challenge: maintaining stable brightness through precise current control. Small voltage changes, he noted, can produce large swings in current.

Earlier driver circuits often struggled with inefficiency, excessive size, or thermal reliability problems. In contrast, Rickett testified that the patented design uses a resonant circuit and an output buffer. This combination delivers a substantially constant current. Consequently, the design reduces thermal stress while improving efficiency and compactness compared to prior approaches.

He walked the jury through all five of elements for all six of the products. He confirmed that all six are in violation of all five elements.

Cross-Examination Shifts to Heat Sink Analogies

During cross-examination in the Signify vs Lepro patent trial, Nicholas Brown questioned Rickett about his hourly rate. Rickett responded that he charges $695 per hour.

Brown then introduced a ceramic coffee mug and a Starbucks paper cup. He asked whether either object could qualify as a heat sink. The courtroom audio made Rickett’s response difficult to hear. Nevertheless, Brown pressed the issue for roughly ten minutes, returning repeatedly to whether everyday objects could function as heat sinks under the patent definition. Regardless of how Rickett answered, I failed to understand the point that was attempted.

Aluminum Foil Demonstration Draws Jury Attention

Next, Brown approached Rickett with an energized green Lepro LED bulb. Using an iPad, he turned the bulb off and introduced Exhibit 688 into evidence. Next he changed colors from green to blue to red and back to green. The jury looked impressed.

Brown then held up a box of aluminum foil. He cut off a large sheet and folded it four times. It was a rare time when every single person in the courtroom appeared to be engrossed in the trial.   Next he poked a hole in the folded foil and wrapped it around the bulb.  He aimed the energized bulb toward the jury and changed its color using the iPad.  Because of the hole in the foil, the jury was able to watch the color change from green to red to blue.  Clearly the jury was energized.

However, Brown did not stated the point of the exercise.  Yesterday we wrote about the importance of the antenna location.  Perhaps this was an implication that the antenna could still function when surrounded by metal. If so, maybe Brown was suggesting that  antenna placement inside the bulb was irrelevant.

But if your humble editor can’t figure out the point, can the jury?