Application Watch: Displays with high pixel density fuel further miniaturization in SMD LEDs

SMD LED manufacturers are planning to introduce 1010, 0808, 0707 and 0606 types to meet the trend for advertising displays with small pixel pitches.

For more vivid colors and sharp images, LED displays used in advertising are moving toward a pixel pitch of less than 2.5mm, with those having 1.5mm comprising the trend in recent years. The latter type of panels requires SMD diodes in 1010 packages, which are much smaller than typical 2828 and 3535 ones available in mainland China. To keep up with the trend, more LED makers there are expected to follow through. A few, including HongKong Double Light Electronics Technology Co. Ltd, have released models in such size.

Manufacturers of the component are also looking to press on with miniaturization to introduce variants more compact than 1010. This is because, on the local front, many LED display companies are directing R&D toward P1.2 and P0.9 kinds or those respectively with 1.2 and 0.9mm pixel pitches. The former adopts 0808 diodes, while the second such as those launched by Unilumin and Voury use 0606 or 0707 variants. Kingbright Electronic Co. Ltd, a Taiwan supplier interviewed for this report, offers 0606 SMD LEDs.

Pending wider production of smaller SMD diodes, mainland makers will continue to turn out units in conventional sizes as well as DIP units. The latter is still broadly utilized in LED displays with 10 and 20mm pixel pitches, although such panels will have a gradually shrinking market in several years. Displays with 6 and 8mm pixel pitches or P6 and P8 types will replace them in the mainstream. These usually adopt SMD or COB LEDs. The second will dominate in panels with 4mm and lower pixel pitches in the years ahead so some local SMD LED suppliers are also planning to shift R&D direction to COB technology.

The global LED display industry is a dynamic market, with production value forecast to increase to $1.94 billion in 2021 from $1.63 billion in 2017 based on statistics from LEDinside. Types with small pixel pitches will be the main growth drivers, with expected CAGR of 12 percent from 2017 to 2021.

SMD LEDs for panels used in advertising stand to continue benefiting from this development. In the mainland, production value is forecast to maintain a 5 to 10 percent annual rise in the next five years. Domestic companies are just as optimistic about exports, counting on the same rate at least in one or two years. They ship between 30 and 80 percent of total output overseas.

There are more than 500 companies turning out SMD LEDs for advertising displays in the mainland. Up to two-thirds are locally owned operations and the rest have investment mainly from Hong Kong and Taiwan. The key players in the former group include Foshan NationStar, Shenzhen Refond and Guangzhou Hongli, and among the counterparts in the second are Everlight and Lite-On.

All manufacturers also develop and market other optoelectronic products such as DIP LEDs, and LED modules, displays and lights. Shenzhen Refond has SMD, IR and power LEDs, COB LED modules and LED lighting products, which are widely used in LED displays, home appliances and automotive applications.

Over 70 percent of the makers are in the provinces of Guangdong and Fujian, specifically in the cities of Shenzhen, Dongguan, Guangzhou and Foshan in the first and Xiamen in the latter. Many are also in Suzhou in the province of Jiangsu and Hangzhou in Zhejiang.

Typical selection

In mainstream supply are SMD LEDs for P3 to P12 advertising displays. The common sizes on offer are 2828 for P3, P4, P5, P6 and P8 applications, while 3535 types target P8, P10 and P12 units. The range also includes 3528, 3525 and 2121 diodes.

All releases come in non- and water-resistant variants.

Key component LED chips are sourced mostly from foreign companies such as Epistar and Cree, while the local alternatives are from San'an, HC SemiTek and Silan Azure. The other manufacturing inputs, including gold wires, brackets and adhesives, are usually obtained in the domestic market, although makers accommodate requests for imported versions.

Despite the slight increase in the cost of LED chips in the past year, the majority of suppliers maintained their prices to stay competitive. In coming months, a stable trend is forecast.

The products in this gallery have been handpicked by our mainland China-based market analyst for representing current trends in SMD LEDs from mainland China and Taiwan makers.

80mcd SMD LED in 1010 package

The model DL-TOP1010RGBC-A2 SMD RGB LED from HongKong Double Light Electronics Technology Co. Ltd uses a 1010 package. It has a 365nm peak emission wavelength and 80mcd luminous intensity, while the viewing angle is 120 degrees. The forward voltage is 3.2V.

The order quantity is negotiable and for delivery within 7 days.

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0606 SMD LED with clear lens

Kingbright Electronic Co. Ltd’s KPGF-0606GBRC-120 model is a 0606 SMD LED with 5mA rated current. It comes with a clear lens and has a viewing angle of 130, 140 or 145 degrees.

The order quantity for this RoHS-compliant unit is negotiable. The delivery lead time is 7 days.

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3528 SMD RGB LED

In 3528 size, this model 3528RGB SMD LED from Shenzhen Best LED Opto-electronic Co. Ltd has luminous intensity of 1,000 to 1,500mcd in red mode, 1,000 to 1,300mcd in blue and 3,000 to 4,000mcd in green.

The 0.6W unit has a negotiable order quantity. Delivery takes 14 days.

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1204 SMD LED has 150-degree viewing angle

Solidlite Corp. has the SP1204H-3C-020mA-4701 model, a 1204 SMD LED with 20 or 30mA DC forward current, 80 or 100mA pulse current and 5V reverse voltage. The power dissipation is 72mW.

The luminous intensity is 100 to 200mcd in red, 300 to 500mcd in green and 40 to 90mcd in blue. The unit has a 150-degree viewing angle. It operates in -40 to 85 C.

The order quantity is negotiable. Delivery lead time is 7 days.