5mm Flat Top Concave LED

5mm flat-top concave LEDs have a unique lens with a center depression that refracts light outward rather than forward, creating the widest light…

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5mm flat-top concave LEDs have a unique lens with a center depression that refracts light outward rather than forward, creating the widest light distribution of any 5mm LED package — approaching true omnidirectional emission. This makes them the standard replacement for incandescent bulbs in LED Christmas light strings and the ideal choice for any decorative application where the LED body itself is the visible light source, not a hidden element behind a panel. Also marketed as “wide-angle 5mm,” “5mm conical,” or “concave LED,” these are the same LEDs used in commercial wide-angle LED Christmas light sets sold by major brands.

Christmas and holiday lighting: The concave lens was specifically designed for LED string lights where each bulb is visible from every direction on a tree, wreath, roofline, or window frame. Traditional C6, C7, and C9 incandescent string lights radiate in all directions; a standard round-top or flat-top LED would create a bright spot in front and darkness at the sides. The concave refraction pattern solves this completely by pushing light out laterally past 160°. Warm white concave LEDs produce the soft, even glow that holiday lighting installers and DoItYourselfChristmas.com (DIYC) enthusiasts demand for residential and commercial string light builds. Cool white gives a crisp, modern look popular for commercial installations and synchronized light shows. Red, green, and blue concave LEDs are standard for multi-color strings. If you are building custom C7 or C9 retrofit LED bulbs to fit existing incandescent sockets, the 5mm concave LED is the standard emitter inside those retrofit housings.

Automotive gauge cluster backlighting: The concave lens also excels behind automotive instrument panels, spreading light more evenly than even a standard flat-top LED. For Silverado, Sierra, Tahoe, Suburban, Civic, Accord, Wrangler TJ/JK, and Mustang instrument cluster conversions, concave LEDs provide the most uniform gauge face illumination of any through-hole option. If you have been experiencing uneven bright spots or dark edges with flat-top LEDs, concave is the next step up in uniformity. The extreme lateral spread fills the cavity behind the gauge face from edge to edge. Automotive forums (GM Truck Club, Honda-Tech, JeepForum) document this approach for the most demanding cluster conversion builds.

Decorative, display, and prop applications: Department 56 and Lemax Christmas village building windows, edge-lit acrylic signs, small-format lightboxes, cosplay props behind translucent materials, and escape room decorative accent elements all benefit from the near-omnidirectional output. The concave LED eliminates the directional bias that every other lens shape introduces. For cosplay armor with translucent panels, a concave LED behind each panel provides the most even glow with the fewest dark spots. Escape room builders use concave LEDs inside decorative fixtures where the light must be visible from any angle in a 360° walk-around environment.

Colors, wavelengths, and lens characteristics: We stock 5mm flat-top concave LEDs in multiple colors including red, orange, amber, yellow, green, blue, cool white, warm white, UV, and pink. The concave lens depression is molded into the top of a standard 5mm LED body — same base diameter, same lead spacing, same package height as any other 5mm LED. The depression acts as a diverging lens, bending light outward past the normal forward hemisphere. Each product page lists the peak wavelength in nanometers and brightness in millicandela (mcd). Because the lens disperses light so broadly, mcd ratings will appear lower than a round-top or flat-top of the same color — but the visible illumination from the side and rear is dramatically better.

Electrical specs and resistor selection: Forward voltage: red/orange/yellow/amber ≈ 2.0–2.2V; blue/green/white/UV ≈ 3.0–3.2V. Maximum forward current: 20mA. Always use a series current-limiting resistor. Standard values: 12V → 510Ω for red, 470Ω for white/blue; 5V → 150Ω for red, 100Ω for white. Use our LED resistor calculator for any supply voltage. For AC-powered Christmas light builds using a 120V-to-12V transformer, add a bridge rectifier and smoothing capacitor to convert to DC before the LED string. See the AC/DCC wiring guide for a complete diagram. The same approach works for model railroad accessory AC transformers and DCC track power. New to LEDs? Pre-wired LEDs include the resistor on the wire for zero-math installation.

Mounting, physical dimensions, and related products: The 5mm concave LED fits a standard 5.2mm (13/64″) panel-mount hole and standard 5mm LED holders and bezels. Lead spacing is 2.54mm (0.1″) for breadboard and perfboard compatibility. The longer lead is the anode (+); the shorter lead with a flat on the base is the cathode (−). The only physical difference from a standard 5mm LED is the lens surface — a center depression instead of a dome or flat plane. For panel-mount gauge backlighting where you want flush mounting, concave LEDs work in the same holders and bezels as flat-top LEDs. For comparison: 5mm flat-top LEDs spread light 100–160° with a smooth level surface — better for indicators and bezel-mounted builds. 5mm straw hat LEDs spread 120–140° with a flattened dome for building interiors and streetlamps. 5mm round-top LEDs focus into a 15–30° beam for headlights and spotlights. For plug-and-play wiring, pre-wired LEDs come ready for 5V, 6V, 9V, or 12V. For automatic blinking or color-cycling, animated LEDs have a built-in controller IC.

Frequently Asked Questions

A flat-top LED has a level surface that spreads light 100–160° but still emits most light in the forward hemisphere. A concave LED has a center depression that acts as a diverging lens, refracting light outward past 160° and approaching omnidirectional output. The concave design is specifically optimized for applications where the LED is visible from all sides, such as Christmas string lights and decorative installations.
Yes. The 5mm concave LED is the standard form factor inside commercial “wide-angle” LED Christmas lights (sometimes marketed as “5mm conical,” “5mm wide-angle,” or “M5 LED”). The concave lens produces the omnidirectional glow needed for tree wrapping, roofline strings, and wreath lighting, where each bulb must be visible from every angle. Warm white is the most popular color for residential use; cool white and multi-color for commercial and synchronized displays.
Yes, and they often produce the most uniform backlighting of any through-hole LED. The extreme lateral emission fills the space behind the gauge face more evenly than a flat-top LED, which still has a slight forward bias. If you have tried flat-top LEDs in a cluster conversion and still see faint hot spots or dark edges, concave LEDs are the next step up in uniformity.
Yes. The package is a standard 5mm through-hole LED with standard 2.54mm lead spacing. Concave LEDs fit 5mm LED holders, 5.2mm panel holes, and breadboards. Only the lens surface is different — a center depression instead of a dome or flat surface. All wiring, resistor values, and mounting hardware are identical to any other 5mm LED.
The same resistor values as any standard 20mA 5mm LED. At 12V: red ≈ 510Ω, white/blue ≈ 470Ω. At 5V: red ≈ 150Ω, white/blue ≈ 100Ω. The concave lens changes only the light pattern, not the electrical specs. Use our LED resistor calculator for any supply voltage.
LEDs require DC power. If your Christmas light setup uses a 120V-to-12V AC transformer, add a bridge rectifier and smoothing capacitor to convert to clean DC before the LED string. Many DIY Christmas light builders use a 12V DC power supply directly to avoid the extra components. For model railroad AC transformers or DCC track power, the same bridge rectifier approach works. See our AC/DCC wiring guide for a complete wiring diagram.