Small hole imaging, why through the triangular hole or round bright spots,

Small hole imaging knowledge points such as the air glider down:

1.The image formed in the image of the hole is the image of the light source, regardless of the shape of the hole.

2.The statues made of small holes are all upside down.

3.Whether the image of the hole is enlarged or reduced depends on the comparison of object distance with image distance.

1) When the image distance is equal to the object distance, it becomes an equal image;

2) When the image distance is greater than the object distance, it becomes an enlarged image;

3) When the image distance is less than the object distance, it becomes a reduced image.

An object can be seen as being made up of an infinite number of points, each of which is a point of light. Ideally, due to the linear propagation of light, the light emitted by each light emitting point passes through the small holes and forms a single light spot on the light screen.

According to geometry, the luminous point and the light point falling on the light screen are symmetrical with respect to the center of the small hole, so the light behind the small hole makes the cross-sectional pattern of the hole point and the object symmetrical as well. And because the light itself is emitted by the object point, it carries the characteristics of the object, such as shape, color, finish, etc., so the light point is also the image point, and the cross-sectional pattern of the light point is also the image of the object.

Using the diffuse reflection of the image on the light screen, we can see the image formed by the small hole, which is the mechanism of small hole imaging. In fact, because the small hole has a certain geometric size and is not a geometric point, the light emitted by the object point forms a diffused beam after passing through the small hole, and when it falls on the light screen, it becomes a light spot (image spot) instead of a light point.

When the light spots overlap with each other, the image is distorted. The larger the hole, the larger the light spot, the more obvious the overlap between the light spots, and the more serious the image distortion. Therefore, there is always distortion in the image formed by the small hole, and the authenticity of the lost potato mainly depends on the size of the relative aperture of the small hole.

Independent. Assuming that the hole is small enough to allow only one ray of light to pass through, a clear image of the object is received on the light screen. If the hole happens to allow two rays of light to pass through, then what is received on the light screen is a superposition of the two images.

As long as the hole is small enough, you can't detect the change. If the hole is large enough, it cannot be clearly imaged. You can't observe this phenomenon.

So the shape of the hole does not affect the shape of the image.

Aperture imaging is a physical phenomenon that occurs when light travels in a straight line. With this phenomenon, it can be proved that light travels in a straight line in the same homogeneous medium.

About 2,450 years ago, a Chinese scholar Mo Zhai (Mozi) and his students did the first experiment on the world to form an inverted image of a small hole, explaining the reason for the inverted image of the small hole and pointing out the nature of the straight line progression of light. This is the first scientific explanation of the linear propagation of light.

If a plate with a small hole is used to block between the wall and the object, the reflection of the object will be formed on the wall, and we call this phenomenon the image of the hole. When the middle plate is moved back and forth, the size of the image on the wall also changes, which illustrates the nature of light propagation in a straight line.

If the two holes are spaced horizontally, then the image should be blurred laterally. However, as long as the hole is close enough, it will be difficult for you to detect this change. If the hole is a little bigger, but not so big, and it's still round, and it passes through exactly 10 rays evenly, then the light screen should receive an image of an object that is blurred a little bit in all the squares.

But this change is still very small and difficult for you to observe. If the hole becomes a small square hole, then it is expected that the image on the light screen will be blurred in the diagonal direction.

In the aperture imaging experiment, if a spot is obtained on the light screen instead of a clear real image, the aperture is too large.

For example, in the above figure, take a ray of light as an example: after the light emitted from the tip of the candle flame A passes through the small hole, it can only propagate in a straight line to the corresponding point A' on the light screen, and then A' is the image formed by the point A. If the hole is too large, there will be many strips of light from A that pass through the hole and hit different points on the light screen to form a spot.

If the light emitted by all the points on the candle passes through a large hole in this way, there will not be a definite image point on the light screen, and what you will see on the light screen is a spot of light.

You can do experiments at home: candles, small holes (a small hole in a thick cardboard with a pin), light screens (with walls instead). Adjust the distance from the candle flame to the small hole, and observe the size of the image on the wall; Use chopsticks to prick a small hole and see if it can still be imaged?

After analysis, there may be reasonsThere are 3 types as follows:

1. [The distance between the object and the small hole is too far] 2. [The distance between the optical frequency and the small hole is too close] 3. [The aperture of the small hole is too large].

Use a plate with a small hole to block between the screen and the object, and the inverted image of the object will be formed on the screen, which we call this phenomenon small hole imaging.

Move the middle plate back and forth, and the size of the image will also change. This phenomenon reflects the nature of light propagating in a straight line.

The image of the small aperture is a real image, which has nothing to do with the shape of the void, it is the linear propagation of light, and the light can be transmitted.

The larger the hole, the less clear the image. As long as the hole is small enough, its shape, whether it is square, round, or oblate, has no effect on the clarity of the image and the shape of the image.

The aperture is imaged as a real image, so when you look at the sun with the aperture, you see an image of the sun, which is naturally a round bright spot.

a. The circular spot formed through the small hole is the image, and the spot formed through the large hole is formed because the paper (or other obstruction) around the hole blocks the propagation of light; therefore a is correct;

b. From the reason for the formation of the light spot, it can be seen that the light spot (image) formed by the small hole has nothing to do with the blind shape of the small hole, and the light spot formed by the large hole is related to the shape of the large hole; Therefore b is correct;

c. The size of the spot (image) formed by the small hole is related to the distance from the hole to the ground, the farther the distance, the larger the spot; The size of the spot formed by the large hole has nothing to do with the clear and pure distance from the hole to the ground; Therefore c is wrong;

d. The spot image formed by the small hole and the spot formed by the large hole are not the image, but they are formed by the straight propagation of light; Therefore d is correct

Therefore, c