Citizen Electronics Co., Ltd. (Head Office: Fujiyoshida City, Yamanashi Prefecture. President: Yoshihiro Gohta) has developed LED packages for lighting (207 models in total), ‘COB ^*1 Series, Version 4,’ that provide the world’s highest level of luminous efficacy.  The products will be exhibited during the ‘LIGHTFAIR INTERNATIONAL 2015’ in New York, U.S. from May 5, 2015.

(All images courtesy of Citizen)

Background and advantages of development

Citizen Electronics developed LED packages for lighting, ‘COB Series, Version 1,’ in 2011 and has introduced upgraded products into the market as the COB Series thereafter.  We are releasing ‘COB Series, Version 4’ in which performances such as luminous efficacy and luminous flux have been increased by up to 15 % through reselection and improvement of materials such as dies.

As LED lighting has penetrated the market, there is a wide variety of customer demand for not only brightness and luminous efficacy, but ‘quality of light,’ in order to enable an illuminated object to look more beautiful.  The developed products, Version 4, meet these diversified demands through significant expansion of the lineup including 13 types and 207 models.

◆Main features

1. Luminous efficacy and luminous flux have been improved by a maximum of 15 % over that of the current model and the world’s highest level of luminous efficacy has been achieved

Luminous efficacy and luminous flux have been improved by a maximum of 15 % over those of the current model through enhancement of light extraction efficiency and heat dissipation with reselection and improvement of materials such as dies.  The developed products have achieved the world’s highest level of luminous efficacy in COB-type high-wattage LEDs and contribute to energy conservation for luminaires.

* Comparison of the two models below made when they light up under the same conditions

(3,000K, Ra 80 min., Tj=85ºC)

      Luminous flux        Luminous efficacy  Product code

New product: 2,182 lm 140 lm/W CLU036-1205C1 Current model: 1,896 lm 122 lm/W CLU034-1205B8

      [about 15 % increase]     [about 15 % increase]    

2. Lineup of 207 models in total

As not only has brightness been focused on but the need for quality of light such as improved color rendering ^*2 has increased in recent years, Citizen Electronics has expanded the lineup of the ultrahigh color rendering type (Ra 97 typ.) and the preferable color type (below B.B.L.) ^*3.  Moreover, a color variation of 6,500K has been added to the standard type (Ra 80 min.) and 207 models in total are being released at the same time.  These models meet the diversified demand of customers.

3. Brightness has increased by up to 50 % through expansion of the driving power range Larger current can be applied to one LED package than that of the current model due to enhancement of heat dissipation with improvement of the package.  Expansion of the range of driving power has expanded the range of luminous flux and increased brightness by up to 50 %.

      Range of driving power  Luminous flux        Product code

New product:         0.8 W to 45.3 W 144 lm to 5,518 lm     CLU036-1205C1

Current model:      0.8 W to 33.1 W 111 lm to 3,637 lm     CLU034-1205B8

      [12 W expansion]   [about 50 % increase]    

4. High-heat dissipation structure and uniform-light-emitting area

・Citizen Electronics has adopted the Chip on Aluminum technique (patented by Citizen Electronics), which is a high-heat dissipation technique where LED dies are directly mounted on an aluminum board.

・LED dies are placed to generate uniform light in the light emitting area considering optimization of

the light distribution design of luminaires                  

・As the new products are compliant with the chromaticity control standard “3-Step MacAdam ellipses” which is about a ninth of the chromaticity range of ANSI C78.377 ^*4, chromaticity variations in LEDs are rarely noticed (excluding the Ra 70 min. type).

Chromaticity range of ANSI C78.377 Chromaticity range of 3-Step MacAdam ellipse

5. Selection of LEDs is simplified through use of a selector tool

In order to support luminaire makers to select the desired LED, Citizen Electronics provides a product selector tool (software tool) on its website.  By entering desired conditions such as the amount of luminous flux, it is possible to narrow down the selection of appropriate types of LEDs.

◆Main specifications

 (5,000K, Ra 80 min., Tc=25ºC)

Applications

*1 COB: stands for Chip on Board and is a structure where LED dies are directly mounted on a board.

*2 Color rendering: If quality of a light source changes, an object may appear to be a different color.  Thus, ‘color rendering’ is the effect of quality of a light source on the color appearance of objects.  Color rendering is generally indicated in a general color rendering index (Ra) and it is said that the nearer to 100 Ra is, the closer to natural light the color of light looks and the better it is.

*3 Preferable color type (below B.B.L.): Generally LEDs for lighting have the white chromaticity range centering on the curve (B.B.L.) located in the center of the chromaticity diagram below.  However, as there are different color shades above B.B.L. and below B.B.L., we have set chromaticity ranges only below B.B.L. and ”CITILED The Light Engine” is a brand name of LEDs for lighting manufactured by CITIZEN ELECTRONICS CO., Japan. CITILED is a registered trademark of CITIZEN ELECTRONICS CO., Japan.

Information provided on this press release was accurate at the time of announcement.