THE DIFFERENCE BETWEEN SMD AND DIP LEDS Pros and Cons

THE DIFFERENCE BETWEEN SMD AND DIP LEDS

Two main kinds of LEDs are used to manufacture LED displays. The predominant DIP modules were the only available kind in the late 20th century, while the SMD module quickly became popular after the turn of the century.

In the signage industry, the two module types run a neck-and-neck race, but are quickly finding their place. Their distinctive pros and cons have placed DIP displays as the go-to outdoor LED, and SMD displays as a very popular indoor solution.

This article is going to take a look at what the two types of LEDs are, and address their strengths and weaknesses in the digital signage arena.

DIP

The Direct In-line Package (DIP) module is assembled from three separate colors of the more archetypal, bubble-shaped LED with two connector feet. The diodes are stamped into a pre-drilled Printed Circuit Board (PCB) using a process known as “through-hole” mounting. The legs are then soldered onto pads on the opposite side, which can be done by hand or with machines.  DIP modules are typically used for outdoor applications, because having separate, encapsulated diodes makes them better at dispersing heat and more weather resistant than SMD modules.

The technology for an affordable DIP diode has been around since about 1968 as a replacement for lamp displays, so plenty of machinery exists to create DIP modules to the necessary tolerance for an electronic message center. As a result, the DIP module is relatively inexpensive, and price obviously fluctuates according to pixel pitch. The closer the LEDs are mounted, the more expensive the module is.

Once assembled, all outdoor modules are front-coated in heat-dissipating silicone for weather-proofing. Most outdoor modules also have a conformal coated back, but a select few LED sign manufacturers choose to also “pot” (fully encapsulate) the back of the module for additional weather-proofing.

SMD

The Surface Mounted Diode (SMD) is an encapsulated LED that has all three colors of diode in a slim tube that is soldered directly onto a circuit board printed with solder pads instead of having mounting holes drilled into it. SMD diodes can be made smaller and placed closer together since they’re only mounted onto one surface of the board.

Surface mount diodes are typically used for smaller pixel pitches in indoor applications. The largest SMD module typically seen is a 6mm pixel pitch, and it can be made to sizes of 4mm and smaller.

As technology advances and the precision of machinery increases, these new modules are not only becoming more affordable, but are seeing a longer working life-span, and are becoming more reliable.

In a number of applications from mobile devices to indicator lights, SMD LEDs have clearly replaced DIP modules. They are, however, not poised to dominate the outdoor digital signage industry for a handful of reasons.

Pros and Cons

A 6mm DIP and 6mm SMD module comparison.

The SMD module is a promising up-and-comer in the LED Sign world, and has completely replaced DIP LEDs in many other applications. However, the requirement for newer, more precise machinery throughout the assembly process has created a considerable price gap between the two. Although DIP modules remain cheaper, the price gap continues to shrink as better technology becomes available.

SMD modules also need to be built to a tighter machine tolerance to demonstrate the same working life as DIP modules, and as of yet, their lifespan remains considerably shorter. They consume more power, and are dimmer, weighing in at 6500 NITs compared to the 12,000 NITs that a DIP module can produce. Some of this has to do with the fact that a DIP LED’s distinct, bulbous shape acts as a lens to better disperse light.

Also, when a surface mount module is turned off, the diodes appear white from the coating at the back of the chip. Black face SMD diodes have been developed as a solution for the loss of contrast that surface mount displays suffer, but the white in the back of the diodes still keep them from exhibiting the same contrast as their older counterpart.

SMD diodes have a home-field advantage for interior signage because they can be built to smaller pixel pitches and have an excellent display quality. With better machinery, SMD modules will soon be built to tighter and tighter pixel pitches, all while closing the price gap with DIP units.