Citizen Electronics has a new answer to one of the oldest complaints about COB spotlights: the yellow ring at the edge of the beam. Its CITILED COB Series Type-F, announced in October with volume production scheduled to start this January, reworks the light source itself so the spot comes out even, without a special lens to hide the problem.

What Type-F changes

Most of the effort in LED sources over the last decade went into brightness and efficacy. Citizen's own reasoning for Type-F is that hotels, restaurants and museums now care just as much about the quality of what lands on the wall: a clean, uniform pool of light with no colour fringe. A standard phosphor COB behind a reflector or lens tends to throw a warmer, yellowish ring around a cooler centre, and the luminaire maker usually fixes it with a custom optic.

Type-F tackles it at the source. Citizen reviewed the materials and structure of the emitter to cut the yellow ring and colour shift while keeping the loss of luminous flux to a minimum. The luminance across the emitting surface is also more uniform, which Citizen expects to help with glare in outdoor fittings.

Two spots of light on a dark surface side by side: an even white circle from a Type-F COB on the left and a spot with a warm outer ring from a standard COB on the right
Beam on a surface: Type-F (left) and a standard COB (right). Image: Citizen Electronics.
Two wall-grazing beams side by side: an even white beam from Type-F on the left and a beam with yellow banding from a standard COB on the right
Wall grazing: Type-F (left) against a standard COB (right). Image: Citizen Electronics.

The first parts in the range

The launch covers the High Intensity series Version 4: two package types and 14 models in total. Citizen names spotlights, downlights and landscape lighting such as wall washers as the target applications. High Intensity parts put a lot of light through a small emitting surface, which is exactly where the colour ring is most visible once a narrow optic is added.

Citizen CITILED High Intensity Version 4 Type-F COB on a white ceramic substrate with a round emitting surface
High Intensity Version 4 Type-F. Image: Citizen Electronics.
Larger Citizen CITILED High Intensity Type-F COB package with a round yellow phosphor surface
A larger Type-F package. Image: Citizen Electronics.

Why it matters for luminaire makers here

We supply COBs to fixture makers across the region, and the yellow ring is a familiar argument on site. A client sees the warm halo on a gallery wall or a hotel corridor, and the fixture gets the blame. The usual fixes, a specially designed lens or a diffuser, cost development time and some light. Citizen's point is that Type-F removes most of that work: the same housing and optic give a cleaner beam, and a narrow beam stays clean.

For specifiers the practical change is simple. If a spot or downlight is going into a hospitality or display project where the beam will land on a pale wall, it is worth asking whether the COB inside is a Type-F part.

Getting samples

We have supplied Citizen COBs to the Middle East since our CKD kit days, alongside the heatsinks, holders and reflectors that go with them. Citizen's Type-F product page has the datasheets. If you build fixtures and want to test Type-F against the COB you use today, tell us the package and current and we will arrange samples, or see our OEM and component services.