American Health & Medical Supply International Corp. Co., Ltd. Through-Eyetube EPI Fluorescence Illuminators for Microscopes

经目镜半导体(LED)EPI荧光光源系统，是目前用于生命科学领域中体积最小, 功能性最强、价廉及性价比最高的透过显徽镜目镜的荧光光源。专利LED荧光光源波长能量集中, 均一性佳, 获得最好的激发效果, 光点小，散射角小，聚焦性佳，散热性好，寿命长(10,000小时).

该系统安装方便, 不需其它部件，可直接安装到任一双目镜的显微镜上, 荧光的强度随显徽镜的放大倍数的增加而增强。激发光源包括蓝色光（470nm）、绿色光（530nm）和红色光（625nm）等, 并可根椐使用者的要求而定制，包括以下波长: 395-410nm (UV), 455nm, 470nm, 505nm, 530nm, 590nm, 617nm, 625nm and 850nm。A Through-eyetube (TET) EPI illuminator sends light through one of the eyetubes of a typical binocular head. Light passes through microscope objective and illuminates the sample under observation, same as in a conventional EPI illumination setup. The TET-EPI illuminator fits into an eye tube just like a regular eyepiece. Image can be observed through the other eyepiece or the phototube. Alternatively, TE-EPI illuminator can be inserted into the phototube. In this configuration, images maybe observed through both eyepieces if the microscope is equipped with a beamsplitter between the phototube and the eyetubes.

OPERATION PRINCIPLE

The system diagram (Fig. 1) illustrates a typical microscope equipped with a TET epi-fluorescence illuminator. Light source is a high-power single-color LED. The condensing optics after the LED is arranged so that the LED emitting area is imaged to the exit pupil of the microscope objective, forming a uniform true Kohler illumination over the entire field of view. Light from the LED source is further filtered by an excitation filter which has a bandwidth of a few nm to a few tens of nm. Various visible wavelengths and filter choices are available.

Fluorescence emission from the sample passes through the objective and is then directed to the other eyetube by the beam splitter inside the binocular head. An emission filter in the imaging pass rejects any excitation light reflected by the sample or other internal surfaces of the microscope. It's important that the emission filter has an optical density of 6 or greater in the excitation wavelength range. A convenient arrangement is to mount the emission filter inside the eyepiece in the place designed for reticles. If a camera is used an emission filter should also present either in the camera or elsewhere in the imaging path.

A unique feature of LEDs is that they can be turned on and off almost instantly with a response time on the order of 10ns. The fast response speed makes LEDs potentially useful in time-resolved study of fluorescence. LED light source may also be operated in pulse mode in conjunction with a camera to record the fluorescence image. In the pulse mode the peak driving current of the LED can be several times higher than in CW mode, resulting in higher light power and therefore brighter images. In addition, LEDs are fully dimmable with little change in wavelength.

Other light sources such as arc lamp, lasers, and incandescent light can also be used through a fiber optical cable which connects the light source to the TET illuminator.

*Excitation filter center wavelength would be specially made for 395-410nm (UV), 455nm, 470nm, 505nm, 530nm, 590nm, 617nm, 625nm and 850nm. 激发光源包括蓝色光（470nm）、绿色光（530nm）和红色光（625nm）。