The LED Light bulb "8.7W ordinary bulb type" released by Toshiba Lighting on September 30, 2009 is equivalent to a 60W incandescent bulb. The total luminous flux of the daylight color product is 810lm and the luminous efficiency reaches 93lm/W. To this end, the product uses a COB (Chip On Board) large package with more than 100 small LEDs of several tens of mW grades side by side. The goal of the development of the LED Bulb is to "make the total luminous flux equal to that of the incandescent bulb" (Sano, head of product planning, LED Planning Department, Toshiba Lighting Department). Previous LED bulbs, even those claimed by companies to be equivalent to 60W incandescent bulbs, only meant that "the brightness under the bulb is the same as that of a 60W incandescent bulb" and the total luminous flux emitted by the bulb is low. This time, in order to make the total luminous flux equivalent to the white light bulb, the total luminous flux needs to be increased to 810 lm, which is 1.4 to 1.5 times that of the company's previous products.
In order to achieve this total luminous flux, Toshiba Lighting has adopted a new COB structure. The company's past LED bulbs were packaged with multiple large LED chips of 1W rating and then embedded in LED bulbs. If this structure is used to achieve the total luminous flux to achieve this goal, the number of equipment needs to be greatly increased, and the required installation area may "fill the entire Led Bulb." And heat dissipation is more difficult. Therefore, this product uses a COB structure that is advantageous in terms of mounting area and heat dissipation.
The structure firstly lays more than 100 LED chips on the package bottom plate, that is, the 15 mm square substrate. At this time, the number of filial piety and the arrangement interval of the LED chip need to be optimized by thermal simulation, and on this basis, the shape of the configuration is as close as possible to the square as a whole. Then, the laid chips are wire-bonded and packaged after coating the phosphor. Thereby achieving a COB structure.
Whether large-scale flat-panel packaging can become mainstream In addition to this Toshiba lighting, a large-scale, flat-type white LED package in LED bulbs was also adopted in the product released by Matsushita on September 10, 2009. Most of the previous LED bulbs require 4 to 6 white LED packages with a power of 1W and a power input of 1W. In the future, a large LED is expected to become the mainstream.
The advantage of a large white LED package is the ability to expand the heat sink area of ​​the package. The heat of the white LED package is easily conducted to the outer casing, and the temperature rise of the blue LED chip in the package during lighting is suppressed as much as possible, so that the luminous efficiency is maintained at a high level. In contrast, in the aspect of LED lighting, the installation of a plurality of 1W-class white LED packages has been favored by lighting manufacturers due to high design freedom. Because of the design of LED lighting of various shapes, the design of small LED packages is less restrictive.
An LED industry insider said that the design freedom advantages of using multiple 1W packages are not suitable for LED bulbs. The metal port on which the LED bulb is mounted has been determined to be the same as the existing light source, and even if the shape of the LED bulb is changed, it is still "close to the incandescent bulb". In other words, the design freedom of LED lighting fixtures is not high.
After losing design freedom, large white LED packages offer an advantage in terms of energy efficiency for LED lighting. In addition to the aforementioned heat dissipation advantages, it is believed that LED bulbs are more suitable for large white LED packages because of the small optical loss. Because large white LED packages are close to the surface light source, LED lighting has less "glare". In general, LED lighting requires the installation of a diffused light enclosure to suppress glare. However, the suppression of glare causes light loss. According to LED industry insiders, large white LED packages have less glare, so it is possible to use a housing with a high light transmittance, which can increase the luminous flux emitted by the LED itself to the outside of the bulb, thereby improving the overall luminous efficiency of the bulb.
Figure 1: This LED bulb
Figure 2: Manufacturing steps for COB structure package (when wire bonding is implemented)
In order to achieve this total luminous flux, Toshiba Lighting has adopted a new COB structure. The company's past LED bulbs were packaged with multiple large LED chips of 1W rating and then embedded in LED bulbs. If this structure is used to achieve the total luminous flux to achieve this goal, the number of equipment needs to be greatly increased, and the required installation area may "fill the entire Led Bulb." And heat dissipation is more difficult. Therefore, this product uses a COB structure that is advantageous in terms of mounting area and heat dissipation.
The structure firstly lays more than 100 LED chips on the package bottom plate, that is, the 15 mm square substrate. At this time, the number of filial piety and the arrangement interval of the LED chip need to be optimized by thermal simulation, and on this basis, the shape of the configuration is as close as possible to the square as a whole. Then, the laid chips are wire-bonded and packaged after coating the phosphor. Thereby achieving a COB structure.
Whether large-scale flat-panel packaging can become mainstream In addition to this Toshiba lighting, a large-scale, flat-type white LED package in LED bulbs was also adopted in the product released by Matsushita on September 10, 2009. Most of the previous LED bulbs require 4 to 6 white LED packages with a power of 1W and a power input of 1W. In the future, a large LED is expected to become the mainstream.
The advantage of a large white LED package is the ability to expand the heat sink area of ​​the package. The heat of the white LED package is easily conducted to the outer casing, and the temperature rise of the blue LED chip in the package during lighting is suppressed as much as possible, so that the luminous efficiency is maintained at a high level. In contrast, in the aspect of LED lighting, the installation of a plurality of 1W-class white LED packages has been favored by lighting manufacturers due to high design freedom. Because of the design of LED lighting of various shapes, the design of small LED packages is less restrictive.
An LED industry insider said that the design freedom advantages of using multiple 1W packages are not suitable for LED bulbs. The metal port on which the LED bulb is mounted has been determined to be the same as the existing light source, and even if the shape of the LED bulb is changed, it is still "close to the incandescent bulb". In other words, the design freedom of LED lighting fixtures is not high.
After losing design freedom, large white LED packages offer an advantage in terms of energy efficiency for LED lighting. In addition to the aforementioned heat dissipation advantages, it is believed that LED bulbs are more suitable for large white LED packages because of the small optical loss. Because large white LED packages are close to the surface light source, LED lighting has less "glare". In general, LED lighting requires the installation of a diffused light enclosure to suppress glare. However, the suppression of glare causes light loss. According to LED industry insiders, large white LED packages have less glare, so it is possible to use a housing with a high light transmittance, which can increase the luminous flux emitted by the LED itself to the outside of the bulb, thereby improving the overall luminous efficiency of the bulb.
Figure 1: This LED bulb
Figure 2: Manufacturing steps for COB structure package (when wire bonding is implemented)
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