|
|
此文章由 cxjzhj 原创或转贴，不代表本站立场和观点，版权归 oursteps.com.au 和作者 cxjzhj 所有！转贴必须注明作者、出处和本声明，并保持内容完整
本帖最后由 cxjzhj 于 2018-3-13 19:15 编辑
sssddt 发表于 2018-3-12 22:21 
为了克服传统灯泡机和LED投影机的缺陷，找到了激光，为什么激光投影机不能像灯泡机和LED投影机那样远距离 ...
建议你读一下这篇科技文章。如果你有什么证据能支持你的观点，欢迎交流。虽然你的初衷是好意，但是我作为一个老师的职业病，对一些没有证据支持的观点始终想挑战下。对于激光投影仪，最危险的是激光模块，不过那已经被包得里三层外三层为了防止光源泄露，有空搜下YOUTUBE，有人拆小米激光电视的，那激光模块一大坨被封死的，真正投出来的光线已经过DMD和镜头的散射，危害已经小很多。就像文章里所提，和LED与灯泡机并无大区别，三种机器都不建议直视光源镜头。激光优势之一就在于光源色彩纯正。
远投激光投影机有很多，SONY，松下。。。 还有墨尔本的IMAX就是激光投影影院，那效果不是盖的。倒是超短近投激光机我这几年才看到。
http://www.google.com.au/url?sa= ... cAaP7XK4qe8AUUV-STQ
最关键的一段我摘录下来：
4 Interpretations of the projection light from a projector
4.1 In the case of projection of diffused light from laser device as light source
In the case of the front projector which uses laser device as light source and diffuses the beam and forms it into rectangular beam with uniform intensity and illuminates light valve (liquid crystal panel, DMD) with it, and then projects the expanded image onto the screen through the projection lens, how to deal with its projection light is shown below.
4.1.1 Biomedical safety
In the case of general laser pointer, both of the temporal coherence and spatial coherence are kept; accordingly, when laser light (parallel light) emitted from there is collected with lens, as shown in Figure 4.1.1 (a), all emitted light energy is collected on to micro area of the wave length, and very high energy density is kept at the focal point. For this reason, when laser light (parallel light) goes into human eye, its retina may be damaged by the collected light.
On the other hand, in the case of the front projector that illuminates light valve with diffused laser light and projects it onto the screen, temporal coherence, in some cases, may be kept while spatial coherence is lost; accordingly, in the case where the projection light (diffused light) emitted from there is collected through the lens, as shown in the Figure 4.1.1 (b), only a part of emitted light energy is collected on to finite area of uniform illumination intensity, so that the energy density at the focal point is not so large. For this reason, even in the case where the projection light (diffused light) goes into the human eye, the risk to damage the retina by the collected light is considered to be low.
That is to say, light collection ability through the light projection lens of the projector with laser device as light source is almost same the light collection ability through the light projection lens of the projector with natural light (incoherent light) such as a lamp and LED. ※
※ In the case of the highly monochromatic light, that is, the light spectrum of very narrow band width (equal to temporal coherent light), there are opinion that the threshold level of damage is different from that of other natural light (incoherent light); however, at present, it is not clearly specified that what kind of impact it has on the human body when the light spectrum of very narrow band width becomes in specific.
Accordingly, in the case of the projection light of the front projector that illuminates light valve with diffused laser light and projects it onto the screen, it is not particularly hazardous because it uses laser device as light source; in terms of biomedical, it is considered that it can be handled like other light sources (lamp, LED).
However, regardless of types of light (sunlight, lamp light, LED light, laser light), when one continues to stare at strong light, it is likely to damage one’s eyes; so equally cautions are necessary.
|
本帖子中包含更多资源
您需要 登录 才可以下载或查看，没有帐号？注册
x
评分
-
查看全部评分
|
参加活动--- Scot 家的圣诞日餐(做法全部写完了） (2014-12-25) Scotland 
楼主:sssddt
发表于 2018-3-12 13:03
