LED has ideal properties of a point light source, capable of generating high luminance with a small area. With LED brightness being boosted higher than 1,000 lumens, LED light sources can now be applied in not only consumer and home projectors but also office and commercial models. Epistar, seeing LED's great potential in replacing traditional lamp as projector light sources, started deployment in the projector LED light source market three years ago. Thanks to the introduction of Epistar's unique Co-activation Service model, it has made significant achievements in the projector LED light source market, and its speedy service is an especially contributing factor to Epistar's accomplishments.
Optical engine is the heart of a projector. The optical design focuses on both lumens and etendue. That is, the area and angle of the light beam. Based on target lumens, selection of panels, and the final product dimensions will all affect the design of the emitting area size. Therefore, compared to other LED applications, the design of LED used as projector light sources will need to take both lumens and etendue into consideration, with stringent requirements on the LED driver circuit, emitting area, and control of view angles. Take the 40mil 2-in-1 chip package for example. Even minor changes to gaps between the edge of the emitting area can result in an influence to optical engine efficiency as high as 20%.
Introducing Co-activation Service model to satisfy demands by diverse designs with small quantities
The designs of projector LED light sources are diverse and the productions are usually in small quantities. In the past, optical engine makers generally approached LED package houses for supply of LED chips, and LED package houses could only provide them products that were closest to the specification they needed, without being able to customize LED chips for them.Therefore, optical engine makers often had to evaluate different LED chips several times before finding the most suitable products, or sometimes they simply were unable to find them.
The back-and-forth process between optical engine makers and LED package houses takes a long time, seriously affecting time-to-market. "To solve this problem, optical engine makers have been collaborating with LED chip makers directly from the beginning. This is the best solution," said Scott Chen, Director, Marketing Center Segment Group, Epistar.
Epistar started to promote Co-activation Service model three years ago, which focuses on a core concept of "virtual vertical integration." In the projector industry, Epistar, being an upstream LED light source design partner working with optical engine makers, takes charges in fulfilling design requirements, solving technical problems, and searching for appropriate package house partners. "We are capable of delivering services to customize emitting areas according to customer requirements," emphasized Scott Chen. "We also do this very quickly. We once completed a task a customer asked of us in as short as two weeks." In comparison to other international leaders that generally spend several months on development, Epistar impresses projector makers with its flexible services and speedy delivery.
Optimizing etendue and emitting area to suit various optical designs
Epistar offers LED chips covering full spectrum (wavelengths ranging from ultraviolet to infrared) to meet the needs of a variety of projector opticaldesings, one of the key factors enabling it to provide such flexible and prompt services. "The projector light source produces a white light with a mixture of RGB generally in the ratio of 3:6:1. However, this ratio will slightly vary based on different customers' optical designs, which Epistar is able to tailor in accordance with customers' requirements," stated Penny Chang, Project Deputy Manager, Marketing Center Segment Group, Epistar. It should be noted that Epistar uses phosphor-converted green LED to replace direct green LED so as to overcome the so-called "green gap," a problem of green light wavelength range having inferior efficiency.
Epistar customizes chip emitting areas with professional technology to get better etendue. For highbrightness, Epistar uses a high current density design so that products generate higher lumens when operating at high current. Epistar currently offers 1.1 x 1.63 mm single-chip package with lumens reaching 300 lm and 2.3 x 1.63 mm 2-in-1 chip package with lumens reaching 600 lm. Product size with 1,000 lm are under development.
Light-weight and miniature projection technology driving innovative applications
As traditional lamps get replaced by LED light sources, projector dimensions can be further reduced, allowing projectors to be more portable. In addition, LED has a longer life, therefore saving users from the costs and hassle of having to change lamps about every six months. With all these advantages, the LED projector market is promising. "The LED projector market is on the rise with a CAGR of 30% to 40%. Eight million units projectors were sold in 2014. Small-sized LED projectors have a market scale of 800,000 to one million units. We expect the market share of LED projectors to ramp up year by year with the increase in LED lumens," said Penny Chang.
In addition to projectors, projection technology can also be applied in smart glasses, such as Google Glass, and head-up displays, which are all target markets Epistar is actively expanding into. In general, the introduction of LED light sources enables miniaturization of projection technology, opening up possibilities of more innovative applications. "Of the various applications, the combination of projection technology with smartphones is the most highly anticipated. We continue to watch the trend and devote resources into development of related technologies in order to capture massive market opportunities in the future," indicated Scott Chen.
EPISTAR-Chip for projector applications
EPISTAR-Chip for projector features
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