Сім режими спостереження мікроскоп
2. Dark field DF
The principle of dark field is based on the Tyndall phenomenon in optics. When the dust is directly passed by strong light, the human eye cannot observe it, which is caused by the diffraction of strong light. If the light is cast obliquely on it, due to the reflection of the light, the particle seems to increase in size and is visible to the human eye.
A special accessory required for darkfield observation is a darkfield condenser. Its characteristic is that it does not allow the light beam to pass through the object from bottom to top, but changes the path of the light so that it shoots obliquely towards the object, so that the illuminating light does not directly enter the objective lens, and uses the reflection or diffraction light form by the surface of the object Яскраве зображення. The resolution of dark field observation is much higher than that of bright field observation, up to {{0}}}}.02—0.004
3.Phase contrast PH
During the development of optical microscopes, the success invention of phase contrast microscopy is an important achievement in modern microscopy technology. We know that the the human eye can only distinct the wavelength (color) and amplitude (яскравість) of light waves. For colorless and transparent biological specimens, when the light passes through, the wavelength and amplitude change little, and it is hard to observe the the зразок в світлий поле спостереження. .
The фаза контраст мікроскоп uses the optical path difference of the object to be inspected, that is, ефективно uses the інтерференція явище of light to change the phase difference that cannot be resolved by the human eye into a resolvable amplitude difference, even for colorless and transparent substances. become clearly visible. This greatly falitates the observation of living cells, so phase contrast microscopy is widely Використані в перевернуті мікроскопи.
The basic principle of the phase contrast microscope is to change the optical path difference of the visible light passing through the specimen into an amplitude difference, тим самим покращення контраст між різноманітними структурами і створення різними структурами чітко видимим. світло is refracted after passing through the specimen, deviates from the original optical path, and is delayed by 1/4λ (довжина хвилі) at the same time. Якщо it is is збільшений or зменшений by 1/4λ, the optical path difference стає 1/2λ, and the two beams interfere after the optical axis Strengthen, Growth or Decrease the amplitude, improve the contrast. In terms of structure, phase contrast microscopes have two special features different from ordinary optical microscopes:
1. The annular diaphragm is location between the light source and the condenser, and its function is to make the light passing through the condenser form a hollow light cone and focus it on the specimen.
2. Кільцева фазнапластина A фаза пластина покрита з магнієм фторидом is додана до об'єктивна лінза, which can затримка фаза of пряме світло or diffracted light by 1/4λ. Divided into two type:
A phase plate: Delay the direct light by 1/4λ, add the light waves after the two groups of light waves combine, and increase the amplitude, the specimen structure is brighter than the surrounding medium, forming a bright contrast (or negative contrast).
Phase B plate: Delay the diffracted light by 1/4λ, the light waves of the two groups of light are subtracted after the axis is aligned, and the amplitude becomes smaller, forming a dark contrast (or positive contrast), and the structure is darker than the surrounding medium
Four. Диференціал інтерференція контраст DIC
Диференціал інтерференція мікроскопія з'явився в 1960-ті. Це може не тільки спостереження безбарвний і прозорий об'єкти, але також шоу a тривимірний відчуття of рельєф, and has some переваги that phase contrast microscopy cannot achieve. the спостереження ефект is even better. lifelike.
принцип;
Differential interference called microscopy is the use of a special Wollaston prism to split the light beam. The vibration directions of the split beams are perpendicular to each other and the intensity is equal, and the beams pass through the object at two points that are very close to each other, and there is a slight difference in phase. Since the split distance between the two light beams is extremely small, there is no double image phenomenon, so that the image presents a three-dimensional three-dimensional feeling.
