one. The refracting and refractive index ray is in a uniform isotropic medium, and the two points propagate in a straight line. When passing through transparent objects of different density medium, the refraction phenomenon occurs, which is caused by the different propagation speeds of light in different media. of. When light that is not perpendicular to the transparent object is incident on a transparent object (such as glass) by air, the light changes direction at its interface and forms a refraction angle with the normal.
two. Lens Performance Lenses are the most basic optical components that make up a microscope's optical system. Components such as objective lenses, eyepieces, and condensers are composed of single and multiple lenses. Depending on its shape, it can be divided into convex lens (positive lens) and concave lens (negative lens). When a beam of light parallel to the optical axis passes through the convex lens and intersects at a point, this point is called the "focus", passing through the intersection and perpendicular to the plane of the optical axis, called the "focal plane". There are two focal points, the focus of the object space, called the "object focus", the focal plane of the object, called the "object focal plane"; conversely, the focus of the image space, called "image focus", the The focal plane at the point is called "like the focal plane". After the light passes through the concave lens, it becomes an erect virtual image, and the convex lens becomes an erect real image. The real image can appear on the screen, and the virtual image cannot.
three. The key factor affecting imaging - aberration
Due to objective conditions, any optical system cannot produce a theoretically ideal image, and the presence of various aberrations affects the image quality. The various aberrations are briefly described below.
1. Chromatic aberration is a serious defect in lens imaging. In the case where polychromatic light is a light source, monochromatic light does not produce chromatic aberration. The white light is composed of seven kinds of red orange, yellow, green, blue, and purple. The wavelengths of various light are different, so the refractive index is different when passing through the lens, so that one point on the object side may form a color spot on the image side. The main function of the optical system is achromatic.
The color difference generally has positional chromatic aberration and magnification chromatic aberration. The positional chromatic aberration causes the image to be spotted at any position with a stain or halo, making the image blurry. The magnification chromatic aberration causes the image to have colored edges.
2. The spherical aberration is the monochromatic phase difference of the point on the axis, which is caused by the spherical surface of the lens. The result of the spherical aberration is that after a point is imaged, it is not a bright spot, but a bright spot whose middle bright edge is gradually blurred, thereby affecting the image quality.
The correction of the spherical aberration is normally eliminated by the combination of the lenses. Since the spherical aberration of the convex and concave lenses is reversed, the convex and concave lenses which are optionally made of different materials are glued together to be eliminated. For the old model microscope, the spherical aberration of the objective lens is not completely corrected, and it should be matched with the corresponding compensation eyepiece to achieve the corrective effect. The spherical aberration of a typical new microscope is completely eliminated by the objective lens.
3. The coma is a monochromatic aberration of the off-axis point. When the off-axis object is imaged by a large aperture beam, the emitted beam passes through the lens and does not intersect at a point. The image of a spot will be comminuted, such as a comet, so it is called "comparison".
4. Astigmatic astigmatism is also an off-axis point monochromatic aberration that affects sharpness. When the field of view is large, the object point on the edge is far from the optical axis, and the beam is tilted greatly, causing astigmatism after passing through the lens. The astigmatism causes the original object to become two separate and perpendicular short lines after imaging, which are combined on the ideal image plane to form an elliptical spot. Astigmatism is eliminated by a complex combination of lenses.
5. The field music field is also called "image field bending". When the lens has field curvature, the intersection of the entire beam does not coincide with the ideal image point. Although a clear image point is obtained at each specific point, the entire image plane is a curved surface. This makes it impossible to see the entire image surface at the same time during the microscopic examination, which makes it difficult to observe and photograph. Therefore, the objective lens for studying microscopes is generally a flat field objective lens, which has corrected the curvature of field.
6. Distortion All kinds of aberrations mentioned above except the field curvature affect the sharpness of the image. Distortion is another kind of aberration, and the concentricity of the beam is not destroyed. Therefore, the sharpness of the image is not affected, but the image is distorted in shape as compared with the original object.
References: http://
surgical device vacuum forming white blister tray
Surgical Device Vacuum Forming White Blister Tray
surgical device vacuum forming white blister tray
taicang hexiang packaging material co.,ltd , https://www.medpackhexiang.com