UV LED紫外线杀菌效果该怎么评估？How to evaluate the sterilization effect of UV LED?

根据2020年1月28日，国家卫健委和国家中医药管理局公布的《新型冠状病毒感染的肺炎诊疗方案（试行）第四版》描述：病毒对紫外线和热敏感。也就是说：紫外线能杀死新型冠状病毒（2019-nCoV）。随着紫外线LED的功率提升与技术精进，在市场上已经借由安全、环保、小巧等性能以及无化学残留等优势逐步取代了较低功率的紫外线水银灯管。在本文中，我们列举三个实验说明其中几个因素的重要性，并建议客户根据产品性能和应用领域的不同科学的设计实验条件，评估UV-LED紫外灯的杀菌效果。The novel coronavirus pneumonia diagnosis and treatment plan (Trial) Fourth Edition, published by the National Health Protection Commission and the State Administration of traditional Chinese medicine in January 28, 2020, is described as follows: the virus is sensitive to ultraviolet and heat. Novel coronavirus (2019nCoV) can be killed by ultraviolet rays. With the improvement of UV LED power and technology, it has gradually replaced the lower power UV mercury lamp by the advantages of safety, environmental protection, small size and no chemical residue in the market. In this paper, we list three experiments to illustrate the importance of several factors, and suggest that customers evaluate the germicidal efficacy of UVLED lamps according to different scientific experimental conditions in product performance and application field.

同一产品对不同菌种的杀菌效果对比 Comparison of germicidal efficacy of the same product to different strains

　　某客户委托金鉴实验室对UV LED灯具进行杀菌测试。金鉴工程师测试此款灯具中心波长为275nm，在照射距离1m时其辐射强度为98μW/cm 2，垂直照射15min后对比空白组评价对白色念珠菌、金黄色葡萄球菌及大肠杆菌的杀菌效果。本次试验中试验结果显示同种UV LED虽然辐射强度相同，但对不同菌种的杀菌效果不同。

A client entrusts Jinjian laboratory to carry out sterilization test on UV LED lamps. The center wavelength of the lamp was 275 nm, and the radiation intensity was 98 μ w / cm 2 at the irradiation distance of 1 m. The sterilization effect of the lamp on Candida albicans, Staphylococcus aureus and Escherichia coli was evaluated after 15 minutes of vertical irradiation. The test results showed that although the same UV LED radiation intensity, but the sterilization effect of different strains is different.

二、同一产品不同照射时间的效果对比Comparison of the effects of different exposure time on the same product

　　某客户委托金鉴实验室对UV LED灯珠进行不同条件的杀菌对比测试。金鉴工程师测试送样款UV LED灯珠中心波长为280nm，距离培养基上方垂直照射30s、40s、50s后评价其对大肠杆菌的杀菌效果。本次试验显示在相同照射距离下，UV LED随照射时间的增加，杀菌效果明显增强，本款UV LED紫外线灯对大肠杆菌照射50s后有较好的杀菌效果。测试效果如下所示：

A client entrusts Jinjian laboratory to carry out sterilization contrast test on UV LED lamp beads under different conditions. The center wavelength of the sample UV LED lamp beads was 280nm, which was vertically irradiated for 30s, 40s and 50s from the top of the culture medium to evaluate its bactericidal effect on Escherichia coli. This test shows that under the same irradiation distance, the sterilization effect of UV LED is obviously enhanced with the increase of irradiation time. This UV LED UV lamp has good germicidal effect on Escherichia coli after irradiation for 50s. The test results are as follows:

三、同一产品不同照射距离的效果对比 Comparison of the effects of different irradiation distances of the same product

　　某客户委托金鉴实验室对UV LED灯珠进行杀菌测试，金鉴工程师测试此款UV LED灯珠中心波长为 275nm。距离培养基上方垂直5cm、7cm、10cm照射60S后评价其对金黄色葡萄球菌的杀菌效果。本次试验中UV LED紫外线灯在相同的照射时间下，随着距离的增加，杀菌效果明显降低；在距离5cm时对金黄色葡萄球菌有较好的杀菌效果。测试效果如下所示：

A client entrusted Jinjian laboratory to carry out sterilization test on UV LED lamp beads, and the central wavelength of UV LED lamp beads was 275 nm. The germicidal efficacy of Staphylococcus aureus was evaluated after irradiation for 60s at 5cm, 7cm and 10cm above the medium. In this experiment, UV LED UV lamp in the same irradiation time, with the increase of distance, the bactericidal effect decreased significantly; when the distance was 5cm, it had good bactericidal effect on Staphylococcus aureus. The test results are as follows:

相对于传统紫外线灯，金鉴实验室认为设计UV LED杀菌实验需考虑以下差异：Compared with the traditional UV lamp, Jinjian laboratory thinks that the following differences should be considered in the design of UV LED sterilization experiment:

1. 波段：不同波段紫外线对于细菌，病毒的杀灭效果不同。传统用的紫外汞灯以放电产生以波长为253.7nm为主的紫外辐射，但根据目前最新的研究结果，在264纳米附近，紫外线的杀菌效果可能会更高。在深紫外UVC LED杀菌消毒方面，标准化面临着一系列的挑战，如紫外汞灯杀菌主要在253.7nm，而UVC LED波长主要分布在200-280nm，这为后续应用解决方案带来了一系列差异。Band: the killing effect of ultraviolet rays on bacteria and viruses is different in different wavebands. The traditional ultraviolet mercury lamp produces ultraviolet radiation with the wavelength of 253.7nm by discharge. However, according to the latest research results, the sterilization effect of ultraviolet ray may be higher near 264 nm. In terms of sterilization and disinfection of deep UV UVC led, standardization faces a series of challenges. For example, the sterilization of UV mercury lamp is mainly at 253.7nm, while UVC led wavelength is mainly distributed in 200-280nm, which brings a series of differences for the follow-up application solutions.

2. 紫外线剂量：杀菌需要足够的照射强度、足够的时间及合适的波段。紫外辐射强度取决于紫外光源中有效光谱的发光强度、灯具的光输出角度（光束集中度）、灯具与被辐射物体之间的距离等因素。一般来说，辐射强度越高效果越好；光束越集中于被辐射物体表面杀菌效果越好；距离被辐射物体越近效果越好；累积辐射时间即被照物体在紫外线灯具下的总辐射时间越长效果越好。

Ultraviolet dose: sterilization requires sufficient irradiation intensity, enough time and appropriate wave band. The intensity of ultraviolet radiation depends on the luminous intensity of the effective spectrum in the ultraviolet light source, the light output angle of the lamp (beam concentration), and the distance between the lamp and the object being radiated. Generally speaking, the higher the radiation intensity, the better the effect; the more focused the beam on the surface of the radiated object, the better the sterilization effect; the closer the beam is to the radiated object, the better the effect; the cumulative radiation time, that is, the longer the total radiation time of the irradiated object under the ultraviolet lamp, the better the effect.

3. 发光效率：目前紫外LED在发光效率等方面还无法完全取代汞灯。UVA   LED技术已比较成熟，EQE可达到50-60%，针对UVA的产品未来更多的工作会聚焦于应用系统层面的开发。UVB和UVC波段深紫外LED的外量子效率还比较低，EQE普遍在10%以下，商业化产品基本在1%~3%。

Luminous efficiency: at present, ultraviolet LED can not completely replace mercury lamp in terms of luminous efficiency. UVA LED technology has been relatively mature, EQE can reach 50-60%. For UVA products, more work will focus on the development of application system level in the future. The external quantum efficiency of UVB and UVC band deep ultraviolet LED is still relatively low, EQE is generally below 10%, and commercial products are basically 1% ~ 3%.

4. 应用领域：紫外LED还具有小巧便携、环保安全、易于设计等优点，可以催生出一些不同于传统汞灯的应用需求。比如目前已经出现的便携式的电子消毒产品、电梯扶手杀菌机、扫地机器人等。这是传统紫外光源很难应用的地方。

Application: UV LED also has the advantages of small and portable, environmental protection and safety, easy to design and so on, which can give birth to some application requirements different from the traditional mercury lamp. For example, portable electronic disinfection products, elevator handrail sterilizer, sweeping robot and so on have appeared. This is where traditional UV light sources are difficult to use.

5. 紫外线穿透性：UV LED对直接照射的物体表面具有良好的灭活效果，但穿透性不强，对光线穿透不了的物体内部和被覆盖的部分，没有明显的效果，而传统紫外线灯可利用产生的臭氧的弥散性弥补由于紫外线只沿直线传播、消毒有死角的缺点。Ultraviolet penetration: UV LED has good inactivation effect on the surface of objects directly irradiated, but its penetration is not strong. It has no obvious effect on the interior and covered parts of objects that cannot be penetrated by light. However, the dispersion of ozone produced by traditional ultraviolet lamp can make up for the defect that ultraviolet ray only propagates along a straight line and disinfection has dead angle.

本文节选自This article is excerpted from：http://www.duvtek.com/article/183/