Cree has released its smallest lighting-class LEDs, aiming them at light bulb replacements with wide light dispersion.
There are two devices: XQ-D (700mA) and XQ-B (300mA), both with ceramic substrates and 1.6x1.6mm footprints.
According to Cree product marketing manager Paul Scheidt, making the devices small means, for a given amount of light, the LEDs can be mounted further down the neck of the bulb giving more space for light to be manipulated back towards the neck end of the bulb - better approximating the near-omni-directional output of a standard light bulb.
To help with distribution, the shape of the package puts more light sideways and down compared with other Cree lighting LEDs.
And more LEDs can be squeezed into a give space. "There are a lot of designs where you just don't have any more room," he told Electronics Weekly.
In 5,000K cool white, the XQ-B delivers up 160 lm/W at 0.18W and XQ-D delivers up to 130 lm/W at 1 W.
Inside, the XQ-B has multiple small die and the XQ-D has one larger die. thermal resistance is 17 and 7.5oC/W respectively.
Both LEDs are available in 2,700K to 6,500K color temperatures with some available with a minimum CRI of 80.
To go with the new devices, the firm has several reference and demonstration designs, including one that meets Energy Star requirements for a '60W-type' LED bulb using a translucent cone to disperse light (see diagram) and consuming 11.9W while emitting 822 lm at 69 lm/W from eight LEDs.
Temperature is 90°C. If this is too hot, "add an LED or two to get a little higher efficacy," said Scheidt, pointing out that none of the designs are just simulations: all have been built and tested in LM79 conditions.
