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标题: LED制造技术 [打印本页]
作者: benjamin.zhu 时间: 2008-12-2 16:01
标题: LED制造技术
StockerYale LED TechnologiesOverview of LED Array MethodsLED arrays can be built using several methods. Each method hinges on the manner in which the chips themselves are packaged by the LED semiconductor manufacturer. Examples of packaged, lensed LEDs are shown in Figures 1, 2 and 3.
 |  |
Figure 1: T-Pack LED (Click the image for
a larger version) | Figure 2: Surface mount colored LED
(Click the image for a larger version) |
 | |
Figure 3: Surface mount white-emitting
LED (Click the image for a larger version) | |
These packages can be affixed to a heat-sinking substrate using either "through hole" mounting or surface mounting. The through-hole mounted devices are often referred to as t-pack LEDs (with designations T1, T3, T5, etc.). Arrays built of t-packs are shown in Figures 4.
 |
| Figure 4: LED Array comprised of t-packs |
Importantly, it is also possible to procure wafers of bare, unpackaged chips, also called "dice". See Figures 5 and 6.
 |  |
| Figure 5: Semiconductor LED wafer | Figure 6: Chip-on-board array. In this
example, blue and red LEDs are interleaved
(Click the image for a larger version) |
Using automated pick-and-place equipment, StockerYale takes such individual chips and affixes them to printed circuit boards, creating so-called "chip-on-board" LED arrays. Close-up microscopic photographs of chip-on-board arrays are shown in Figures 7 and 8.
 |  |
Figure 7: Microscopic photograph of
chip-on-board LED array. Close-up. | Figure 8: Microscopic photograph of
chip-on-board LED array. Close-up. |
Figures 9 and 10 show larger regions of chip-on-board arrays.
 |  |
Figure 9: Chip-on-board LED array.
The LED chips are the dark dice in
the gold-colored horizontal stripe at
the top of the board. | Figure 10: Chip-on-board LED array |
An LED array is generally built up on a printed circuit board. The pins or pads or actual surfaces of the LED chips are attached to conductive tracks on the PCB. PCB materials may include fiberglass-filled epoxy, ceramics or metals, depending on thermal and mechanical requirements.
With the LED chips or LED packages attached directly to a printed circuit board, LED arrays are perfectly amenable to electronic control. Indeed, many of the LED arrays produced by StockerYale involve a good deal of electronics, beyond the LED chips themselves.
About Chip-on-BoardAssemblies built from t-pack LEDs are often unsatisfactory, in that they do not always provide sufficiently uniform lighting, and are not well heat-sinked, and they are bulky due to the size (several millimeters) of each t-pack device. Nonetheless, for some applications, t-packs do actually prove to be the most appropriate, cost-effective solution.
In cases in which t-packs cannot provide the required performance however, chip-on-board emerges as the answer. The obvious advantages of chip-on-board LED arrays are
- Compactness
- High intensity due to tight packing density
- High uniformity, even at close working distances
A further -- and very important -- advantage of chip-on-board LED arrays is that they are amenable to superior heat-sinking during continuous, moderate-power operation. The key to efficient design is to ensure that LED PN junction temperatures are as low as possible, which leads to long lifetime as well as wavelength and intensity stability. While the heat from a t-pack LED can only be directed away from the PN junction via the electrodes, the situation is much better when, as in the case of chip-on-board, the chips are placed in intimate contact with a properly designed, thermally efficient substrate structure. See Figure 11. The red arrows indicate the flow of heat.
 |
| Figure 11: Superior thermal performance of Chip-on-board. |
About COBRA™A core competency of StockerYale's LED division revolves around its state-of-the-art automated pick-and-place and wire-bonding equipment. These capabilities, combined with the company's close relationships with various PCB manufacturers and semiconductor houses, enable StockerYale to undertake a program of research on LED chip-on-board methods. StockerYale has recently developed a new proprietary LED array method, dubbed chip-on-board reflective array (COBRA™). This patent pending technology combines the thermal advantages of chip-on-board with the optical efficiency of a reflective cup. The advantages of COBRA are illustrated in Figure 12. In applications requiring particularly high brightness and directional illumination, StockerYale implements the COBRA approach for the construction of the LED array.
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| Figure 12: The optical efficiency of a reflective cup is combined with the superior thermals of C.O.B. in the new proprietary COBRA™ array method. |
作者: benjamin.zhu 时间: 2008-12-2 16:17
标题: 美国StockerYale公司-"SpecBright"高亮度LED机器视觉光源
本帖最后由 benjamin.zhu 于 2009-2-3 15:32 编辑
美国StockerYale公司成立于1946年，为国际领先的光电产品制造商。StockerYale在LED光源领域已经有超过20年的研发和生产历史，其"SpecBright"高亮度LED光源由于：亮度高、光强分布均匀、使用寿命长从而在国际上获得了广泛的应用：
特点：
1.亮度高
2.光强均匀
3.先进散热技术，保持LED工作温度低于45°C,大大延长了LED的使用寿命
——————————————————————————————————————————————————
美国StockerYale中国区总代理：北京路科锐威科技有限公司
地址：北京市海淀区上地东路1号盈创动力E座203A
电话：010-58858423-114（分机）
联系人：朱先生
E-mail:benjamin.zhu@tricombj.com
作者: wypctgu 时间: 2009-5-20 23:46
好东西，千万不要沉了
作者: chenchenchen 时间: 2009-6-18 16:21
不错,学习一下
作者: 再也不能这样 时间: 2009-6-18 17:07
thanks to benjamin.zhu..........
作者: wu4laohu 时间: 2011-5-15 11:39
顶一下，不错不错....
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