The Christmas bubble light: a federal court ruled its own inventor didn't invent it

By Matthew Partsch · Owl and Twig Vintage · September 20, 2026

For seventy years, the story of the Christmas bubble light has started and ended with one name: Carl Otis, the man who supposedly invented it. In 1950, a federal appeals court looked directly at his own patent and ruled that he hadn't — and that ruling is the reason a box of vintage bubble lights pulled from an attic can carry almost any name on the base.

What a bubble light actually does

A bubble light is a small glass tube, usually shaped like a candle, clipped to a Christmas tree branch with a C-6 or C-7 bulb burning underneath it. The tube holds a liquid with a boiling point low enough that the bulb's heat sets it boiling in minutes, and a column of glowing bubbles climbs to the top, disappears, and starts again. Most vintage tubes ran on methylene chloride, chosen for a boiling point of about 104 degrees Fahrenheit — low enough for a nightlight-strength bulb to drive it, high enough that the tube didn't boil dry sitting in a warm room with the lights off.

The plastic base is where a maker's name usually shows up, if it shows up at all, and the tube itself is where the color and the bubble action live. Neither one is where the real story of the object sits. That's in a set of four patents and a federal lawsuit that most sellers, and most collectors, have never read.

The 1935 patent that wasn't a Christmas light

Carl Otis filed his first bubbling-liquid patent on November 27, 1935. It was granted September 26, 1939, as US Patent 2,174,446, and it describes an illuminated advertising sign: glass tubes bent into letters and numbers, filled with a low-boiling liquid such as alcohol or ether, with a wooden plug wedged into the bottom of each tube. Heat from an electric wire wrapped around the tube drove liquid into the plug's pores, where it flashed to vapor fast enough to throw off a steady column of bubbles up through the letter shape. It was a display sign, built for a storefront, not a tree.

Otis didn't file anything aimed at a Christmas tree until six years later. The wooden-plug idea he'd already patented for signage is the same mechanism, at bottom, that would eventually end up under a plastic candle base on millions of American trees.

The inventor a federal court said got there first

Two years after Otis filed his sign patent, a different inventor filed one that solved the identical problem a different way. Philip Rosenblatt, assigned to a company called Biolite Inc., filed on February 8, 1937, for a "display device" — also an illuminated sign, also glass tubes, also a low-boiling liquid. Where Otis used a solid wooden plug, Rosenblatt packed the tube with a tuft of glass wool. Vapor gets trapped in the wool's small interstices and released as a stream of even bubbles, without what Rosenblatt's own filing calls the "violent expulsion" that a bare heated liquid produces on its own. The patent was granted March 31, 1942, as US 2,278,383.

How NOMA turned a borrowed idea into 25 million lights

Otis filed two more patents once he turned his attention to Christmas trees specifically. The first, filed November 6, 1941 and granted July 4, 1944 as US 2,353,063, used a movable "pellucid member" inside the tube to control when vapor was released. The second, filed January 28, 1942 and granted September 4, 1945 as US 2,383,941, replaced that moving part with a solid "fissured mass" — a cracked, porous block sitting at the bottom of the tube, doing the same nucleating job Rosenblatt's glass wool already did for advertising signs five years earlier.

NOMA Electric Corporation, already the country's dominant Christmas lighting company by the 1940s, bought exclusive rights to Otis's patents and put him on staff as a developer. NOMA introduced the Bubble Lite commercially around 1945 to 1946, and it was an immediate hit: more than 25 million units sold in the first two years alone, with Otis collecting a royalty of about three cents per light. For a company that already claimed roughly a third of the American holiday lighting market by 1950, the Bubble Lite became its signature product.

The lawsuit that ended the monopoly

NOMA's exclusive hold on the bubble light lasted about four years. Raylite Electric Corporation, selling a competing bubbling ornament under the Paramount and Kristal Snow names starting in 1947, ended up in court against NOMA, with Otis intervening personally to defend his own patents. The case reached the Second Circuit Court of Appeals twice — once in 1948, and again on February 2, 1950, in Raylite Electric Corp. v. Noma Electric Corp. (Otis, Intervener), 180 F.2d 291.

Judges Augustus N. Hand, Chase, and Frank ruled that Otis's controlling 1945 patent was invalid, and the reasoning went straight back to Rosenblatt. The court found that Rosenblatt's 1942 patent had already disclosed exactly the problem Otis's "fissured mass" claimed to solve: separating a heated liquid into small pockets in close contact with a porous material, so it vaporizes quickly and evenly instead of surging. Substituting one porous material for another, the court held, wasn't invention. Writing for the panel, Judge Chase put it plainly: someone who already knew Rosenblatt's tube worked "did not reach the status of an inventor in substituting" Otis's fissured mass for Rosenblatt's glass wool. Several of the patent's claims were struck down again for being too vague to enforce even apart from the anticipation problem.

Why a box of bubble lights can carry almost any name

The 1950 ruling didn't just settle one lawsuit. It removed the legal barrier that had kept every company but NOMA out of the bubble light business, and manufacturers moved fast. Raylite continued under its Paramount and Sterling lines through the early 1970s. Royal Electric Company of Pawtucket, Rhode Island sold "Sparkling Bubble Lights" from the late 1940s into the mid-1950s. Peerless, marketed as Good-Lite, sold a variant called Shooting Star. Smaller companies with names collectors still sort through today — Reliance, USA Lite, Alps, Holly, World Wide, Glass, Renown — all made their own versions, each with small differences in fluid color, tube shape, and base design.

That is the reason a box pulled from a closet can carry a name that means nothing to most buyers. It isn't a sign of an obscure reproduction or a knockoff. It's a company that had every legal right, after February 1950, to make the exact same product NOMA had spent four years selling as if no one else could.

How to tell a real vintage bubble light

The base shape is the fastest way to place a light in its decade. NOMA's earliest bubble lights, sold before 1948, used a rounded, two-piece "biscuit" base held together with small metal clips at the ventilation holes. NOMA moved to a flatter, one-piece "flying saucer" base by 1948 to 1949, and that shape is what most surviving lights use, across every brand, for the rest of the run. A biscuit-base light with its original clips intact is the rarer of the two by a wide margin, according to collectors who specialize in the category, though no auction record consulted for this guide priced that difference directly.

• Check the base shape first. Rounded two-piece "biscuit" bases predate 1948 and are the scarcer form. Flat one-piece "saucer" bases followed and are what most surviving lights, of any brand, actually have.
• Look at the bulb's own base marking. Collector references point to "Matchless" stamped on the bulb itself as a marker of an early NOMA-era bulb supplier. This is a bulb maker's mark, not the light maker's mark, and the two can separate over decades of replacement bulbs.
• Shake it gently, unplugged and cool. An internal glass slug rattles audibly against the tube. A chemical or wax-based nucleator, more common on later production, stays fixed in place when new but can come loose and rattle after decades of age. A rattle confirms an internal solid is present without confirming which kind.
• Rare tube colors bring real attention. Purple, dark blue, and deep red tubes turn up far less often than the common yellow, green, and clear versions, by the account of longtime collectors. This guide found no dealer or auction price specifically isolating color as the only variable, so treat it as a scarcity signal rather than a fixed premium.
• An intact original box changes the price more than the light inside it does. See what they sell for below — the gap between a loose set and a sealed, boxed one is the widest gap in this category.

The look-alikes: today's reissues

A bubble light sold new today almost never contains any liquid at all. The common modern version is a solid acrylic or plastic tube with the bubble shapes already molded in, lit from below by an LED that never gets hot enough to need one. It looks like the vintage object from across a room and works on an entirely different principle up close: nothing inside it moves, boils, or needs replacing.

The NOMA name itself has changed hands since the original company's 1965 bankruptcy, and that has produced its own case of a familiar name on an unfamiliar product. Canadian Tire currently holds the NOMA trademark in the United States and Canada. When the American licensee Inliten tried to keep selling a liquid-filled Bubble Lite reissue under the NOMA name, it could not reach a licensing agreement with Canadian Tire, and the product now ships under the Sylvania name instead, in a plain generic box and in only two colors, red and orange, down from the range of colors vintage sets offered.

The liquid inside is still a real hazard

What they sell for

Two real auction results anchor this section, both from Jeffrey S. Evans and Associates in September 2024, both lots of mixed, untested, mid-century bubble lights sold by weight of pieces rather than by brand. A lot of 35 NOMA and Royal lights in common colors brought $137.50 with premium, or about $3.93 a light. A lot of 41 Paramount and USALITE lights, described as including rarer colors, brought $500 with premium, about $12.20 a light — roughly three times as much per piece for scarcer color runs in the same rough condition and era.

Current asking listings bracket those two realized results on both sides. A used, untested set of 12 with mixed brands and one rare bakelite-based light asks $30, about $2.50 a light. A used set of 7 with its original box asks $24.99, about $3.57 a light. At the top end, a sealed, unopened 1960s NOMA set of 7 in nice original packaging asks $99.99, about $14.28 a light — more than five times the price of the loose common lot, for lights that have never been plugged in. WorthPoint and LiveAuctioneers both hold additional sold records for individual figural bubble-light pieces, such as a Royal Crown plastic snowman, but both databases lock the actual sale price behind a paid account, so this guide can confirm the item and the venue without confirming the number.

Condition and completeness of the box move the price more than any single design variant does, with one exception: the spread between the two realized auction lots above shows a rare tube color moving the price nearly as much as an unopened box does.

The same pattern of a lapsed monopoly opening a market to a dozen half-remembered names shows up elsewhere on the tree. Our guide to the aluminum Christmas tree traces a different mid-century decoration whose signature brand name never held a live federal trademark at all. And if a cap or a base is the only clue a piece has left, the same problem runs through our guide to Shiny Brite ornaments, where wartime shortages, not a lawsuit, are what dates a box.

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