U-Shaped LED Fluorescent Lamp with a Soft Substrate and Rear Support Frame

The problem

Traditional U-shaped fluorescent lamps are being replaced by LED versions, but building a U-shaped LED tube presents mechanical challenges. Rigid printed circuit boards cannot bend around the tight radius at the base of the U, so manufacturers either cut the board into segments and solder wires across the gap, or force a stiff board into a curve that risks cracking the traces. Both approaches add labor and potential failure points. Furthermore, LEDs generate heat that must be managed. Many designs bolt a separate aluminum heat sink inside the tube, which increases weight, adds parts, and complicates the assembly line. Aligning the LED strips inside the glass tubes also requires fixtures or adhesives applied by hand, slowing production and leading to inconsistent placement.

The solution

This patent describes a U-shaped LED fluorescent lamp that addresses these issues through its rear support frame and a one-piece soft-substrate LED light board.

1. The lamp uses two straight tubes (1) joined at the back by a rear support frame (5).
2. The rear support frame consists of a first U-shaped piece (51) and a second U-shaped piece (52) that fit together.
3. The first U-shaped piece includes first installation parts (511) matching the ends of the straight tubes and a first connection part (512) linking them. At the joint between these parts sits a first positioning column (513).
4. The LED light board (2) is formed as a single soft substrate. It has two light-emitting sections (21) running inside the straight tubes and a middle connecting section (22) joining them.
5. During assembly, the middle connecting section bends around the first positioning column, which acts as a fixed turning point. This sets the bend radius and stops the substrate from over-bending and tearing.
6. The second U-shaped piece (52) has a second positioning post (523) that sleeves over the first positioning column, locking the two frame halves together around the bend.

Who it is for

• Commercial lighting brands looking to expand their LED replacement catalog with U-shaped tubes for office troffers.
• Electrical wholesalers supplying contractors who retrofit older 2x4 fluorescent fixtures with LED U-lamps.
• Amazon sellers and e-commerce distributors focusing on direct-replacement LED tubes for facility maintenance buyers.
• Contract lighting manufacturers seeking a simpler internal structure to reduce assembly time and bill-of-materials costs.

How it works

The main parts

Assembly steps

1. Place the board: The light-emitting sections (21) are inserted into the straight tubes (1) and fixed to the inner walls with an adhesive.
2. Route the bend: The middle connecting section (22) is laid horizontally and wrapped around the vertical first positioning column (513) on the first U-shaped piece (51).
3. Align: The positioning bosses (514) on the first installation parts guide the edges of the soft substrate, keeping it centered.
4. Close the frame: The second U-shaped piece (52) is placed over the first. Its second positioning post (523) slides down over the first positioning column (513).
5. Snap shut: The buckles (526) on the second piece click onto the hooks (517) on the first piece, clamping the frame closed. The first ribs (515) and second ribs (525) press the middle connecting section flat.

Applications

Office ceiling troffers

Facility managers replacing T8 U-bend fluorescent tubes in 2x4 drop ceilings use these LED lamps. The soft substrate ensures the LEDs sit evenly inside the glass tubes, providing uniform light across desk surfaces without dark spots at the bend.

Retail store lighting

Shops using suspended U-tube fixtures benefit from the lower heat output compared to older fluorescents. Because the soft substrate manages heat without a heavy metal sink, the lamp remains lighter, reducing strain on ceiling mounts.

School classrooms

Maintenance teams in schools swap out flickering fluorescent U-tubes for steady LED versions. The snap-together rear support frame speeds up bulk replacements during short summer maintenance windows.

Hospital corridors

Healthcare facilities require reliable, glare-free lighting. The smooth bend guided by the positioning column prevents the micro-cracks that can occur in rigid boards, supporting longer service intervals in areas that run lights continuously.

Where it is less suitable

• Outdoor wet locations - the patent describes glass tubes and a molded frame, but does not specify IP-rated seals for exposed outdoor use.
• High-vibration industrial machinery - glass tubes may not withstand heavy vibration; polycarbonate alternatives would be needed.
• Decorative architectural fixtures - this is a functional replacement lamp designed for standard troffers, not custom shapes.