Convex lens imaging law and principle, the lens is divided into convex lens and concave lens. Lenses are widely used in products and life after they are found to be useful. The magnifying glass is the most familiar convex lens. The imaging rule of convex lens is: the object is placed out of focus, and the real image is inverted on the other side of the convex lens. The real image has There are three types of reduction, equal size, and enlargement. The smaller the object distance, the larger the image distance, and the larger the real image. The object is placed in the focal point, and an upright magnified virtual image is formed on the same side of the convex lens. The larger the object distance, the larger the image distance and the larger the virtual image. The difference from the concave lens is that one enlarges and the other shrinks. The concave lens has a divergent effect on the optics, so its imaging law is much more complicated than that of the convex lens. Let's take a look at the imaging law of the lens together.

Lens real image virtual image

In optics, the image formed by the convergence of actual light is called the real image and can be taken over by the light screen; otherwise, it is called the virtual image, which can only be felt by the eyes. I remember that the physics teacher mentioned the distinction between the real image and the virtual image: "The real image is upside down, while the virtual image is upright." The so-called "upright" and "upside down", of course, are relative to In terms of the original object.

The three kinds of virtual images formed by flat mirrors, convex mirrors, and concave lenses are all upright; while the real images formed by concave mirrors and convex lenses, as well as the real images formed by small aperture imaging, are all inverted. Of course, the concave mirror and the convex lens can also be virtual images, and the two virtual images formed by them are also in an upright state.

Convex lens imaging law

One
1. In addition to the double focal length, inverted to reduce the real image;

2. One-time focal length to two-time focal length, magnify the real image upside down;

3. Within one focal length, upright magnify the virtual image;

4. The real image and the image are on the opposite side of the convex lens, and the virtual image is on the same side of the convex lens.

Second

1. One-fold focal length is divided into virtual and real (and upside down);

2. Two times the focal length and the size;

3. The near image and the far image become larger;

4. The far and near images of the object become smaller;

5. But within one focal length, the far image of the object becomes larger.

Third

Convex lens imaging satisfies 1/v+1/u=1/f, using the special light of the lens as the lens imaging optical path:

1. The object is out of the 2x focal length;

2. The object is between 2x focal length and 1x focal length;

3. The object is in focus;

4. Concave lens imaging light path

Experimental research on the imaging law of the convex lens is: when the object distance is within one focal length, the upright and enlarged virtual image is obtained; when the focal length is between one and two times the focal length, the inverted and enlarged real image is obtained; when the object distance is outside the two times focal length , Get an inverted, reduced real image.

　　For the real image：

　　For the virtual image：(It can be memorized like the real image, but the distance between the virtual image is negative)

　　Magnification：(The virtual image also has a corresponding magnification. If it is a negative value, it means it is a virtual image)

　　Convex lens imaging principle application

The lens is a convex lens, the scene to be photographed is the object, and the film is the screen. The light irradiated on the object is diffusely reflected through the convex lens to form the image of the object on the final film. The film is coated with a light-sensitive material. After exposure to a chemical change, the image of the object is recorded on the film.


　　 1. As for the relationship between object distance and image distance, it is exactly the same as the imaging law of convex lens;


　　 2. When the object approaches, the image gets farther and bigger, and finally becomes a virtual image on the same side;


　　 3. The near image of the object becomes smaller in the far image; the far image of the object becomes larger in the near image.

　　In the learning of lens knowledge, the imaging law of convex lens and its application is an important content. Although we study the imaging situation of convex lens through experiments, in actual practice, the law will still be forgotten, which makes it difficult to do problems. Now introduce a memory technique. From the list and image memory method, the following simple formulas can be summarized: 1x focal length is divided into virtual and real, 2x focal length is divided into size; the real image and the object are inverted, and the near image of the object becomes smaller; the virtual image It's on the same side as the thing, and memorize the formula well. This is the end of the learning content shared today. To learn more about lens, follow us!