What is the law of convex lens imaging?

Before introducing the law of convex lens imaging, the concept of the lower convex lens in optics is introduced. In optics, the actual light is concentrated, and the image that can be presented on the light screen is called a real image; the reverse extension line of light is converged. An image that cannot be rendered on a light screen is called a virtual image. When telling the difference between real and virtual images, one way of distinguishing is often mentioned: "The real images are inverted, and the virtual images are erect."

If it is a thick meniscus concave lens, the situation will be more complicated. When the thickness is large enough, it is equivalent to a Galilean telescope. When the thickness is larger, it is equivalent to a positive lens.

Convex lens imaging law

Rule 1: When the object distance is greater than 2 times the focal length, the image is between 1x focal length and 2x focal length, forming an inverted, reduced real image. At this time, the image distance is smaller than the object distance, the image is smaller than the object, and the object image is different. Application: camera, camera.

Rule 2: When the object distance is equal to 2 times the focal length, then the image distance is also 2 times the focal length, which is an inverted, equal large real image. At this time, the object distance is equal to the image distance, and the image is equal to the size of the object.

Rule 3: When the object distance is less than 2 times the focal length and more than 1 time the focal length, the image distance is greater than 2 times the focal length, and the inverted image is enlarged. At this time, the image distance is larger than the object distance, and the image is larger than the object, and the object image is different from the side. Applications: Projectors, slide projectors, film projectors.

Rule 4: When the object distance is equal to 1 time focal length, it is not imaged and is emitted as parallel light.

Rule 5: When the object distance is less than 1 time focal length, it is an erect, enlarged virtual image. At this time, the image distance is larger than the object distance, and the image is larger than the object and the object is on the same side.