Also known as diffraction grating. It is an optical element that uses the principle of multi-slit diffraction to disperse light (decompose it into spectrum). It is a flat glass or metal plate engraved with a large number of parallel equal-width equidistant slits (scribed lines). The number of slits in the grating is very large, generally tens to thousands per millimeter. The diffraction of monochromatic parallel light through the slits of the grating and the interference between the slits form patterns of wide dark stripes and thin bright stripes, which are called spectral lines. The position of the spectral line varies with the wavelength. When polychromatic light passes through the grating, spectral lines with different wavelengths appear in different positions, forming spectra. The spectrum formed by light passing through grating is the same result of single-slit diffraction and multi-slit interference.

The position of spectral line produced by diffraction grating can be expressed by formula d? Sinq=kl。 Where d= slit width a+ slit spacing b, which is called grating constant; Q is the diffraction angle, L is the wavelength, k=0, 1, 2 ... is the spectral series. This formula can be used to calculate the wavelength of light waves. The fringe produced by grating has the characteristics of high intensity, narrow fringe and wide interval, and has excellent resolution. Because the wavelength can be accurately determined by grating diffraction. The resolution of diffraction grating is R=l/Dl=kN. Where n is the number of slits, the more slits, the brighter and thinner the bright stripes, and the higher the grating resolution. Increasing the number of slits n and improving the resolution is an important subject of grating technology.

The earliest grating was made by German scientist J. Fraunhofer in 182 1 year, with thin metal wires tightly wound on two parallel thin screws. Because it looks like a fence, it is named "iron fence". Modern gratings are engraved on glass or metal plates with precision scribing machines. Grating is the core component of grating spectrograph, and there are many kinds of grating spectrograph. According to whether the light used is transmitted or reflected, it is divided into transmission grating and reflection grating. Reflective gratings are widely used; According to its shape, it can be divided into plane grating and concave grating. In addition, there are holographic gratings, orthogonal gratings, phase gratings, show-off gratings and step gratings.

Question 2: What does a grating mean? An optical device consisting of a large number of parallel slits with equal width and equal spacing is called a grating.

Question 3: What is a grating? Using the principle of optical refraction, parallel lines are pressed out on the transparent film, which is called grating.

Several imaging methods of raster stereoscopic image (raster painting, precisely because stereoscopic painting is only one kind of raster painting effect, including animation, variation painting, stereoscopic painting and 2D+3D fusion effect) ―― the first one: single camera slide shooting synthesis technology; The second type: multi-lens stereo camera real-life shooting technology; The third type: Photoshop software raster image effect design imaging technician the fourth type: stereo software design imaging technology.

1, the relationship between grating spacing and viewing distance

Because of the different refraction and reflection distances of curved lens, it is necessary to watch stereoscopic pictures with different grating spacing (lenticular grating) at a certain distance to show the best effect. The specific parameters are as follows:

Optimum sight distance of grating density

15lpi-24lpi 200cm-300cm

30 lpi-50 lpi 100cm- 150cm

60 psi -80 psi 50 cm

More than 85 lbs. force and 30 cm.

2. Stereo grating alignment

First, cut the grid plate as required. Then, the grating imaging picture is designed and output, and the picture size is slightly larger than the grating plate (bleeding about 3mm on each side). Stick transparent double-sided adhesive tape on the surface of the picture (the release paper of double-sided adhesive tape should also be transparent). Cover the grating plate tightly on the picture (the grating pattern is upward) and align it. The operator places the observation point in the horizontal center of the picture, observes the picture content through the grating plate, and judges whether there is "shearing" phenomenon in the picture effect. If there is a shearing phenomenon, it means that the grating line direction is correct, but it does not match the picture content. At this time, the grating plate should be gently translated until there is no shear phenomenon. The operator translates the observation point from the center of the picture to the left end of the picture until the first cutting point at the left end, and remembers the approximate position. Then, the operator translates the observation point from the center of the picture to the right end of the picture until the first cutting point at the right end, and remembers the approximate position. Determine the distance between the left and right change points and the center of the picture. If the two distances are approximately equal, it means that the edge of each view of the picture is aligned with the edge of the grating line, and the grating plate is aligned with the picture accurately. If the distance between them is very different, it means that although the grating line direction is correct and the picture is consistent with the grating plate direction, it is still not completely consistent. At this time, the grating plate should be gently translated to achieve the above effect.

Key points: When the grid line direction is correct, the shear line of the picture should be parallel to the grid line (generally speaking, the shear line is vertical). After the grating plate is precisely aligned with the picture, the left and right shearing points are symmetrical with respect to the horizontal center of the picture. After the grid plate and the picture are aligned accurately, perform the following installation operations on the grid plate and the picture: press the grid plate and the picture tightly and do not move. Crop the picture according to the edge of the grid plate. Use transparent tape (or cold film) to tightly fix the grid plate with the three sides of the picture, leaving one side as the lead-out line (the lead-out line accounts for about one third of the picture). The grating plate is on the bottom and the picture is on the top. Send it to the cold mounter. The pressure roller of the cold mounting machine should be evenly pressed. Uncover the double-sided adhesive release paper on the opening picture, cut the release paper neatly and stick it on the opening at a uniform speed. Remove the transparent tape (or cold film) fixed on the other three sides, remove the release paper of double-sided adhesive tape, and put the picture on the whole. Pay attention to the handling of joints and don't leave traces. During the whole operation, there should be no dust pollution on the screen and grille surface. There should be no air bubbles after installation.

3. Stereo grating technology

Generally, it refers to grating image technology, which is simply a technology that uses an optical medium-grating material to achieve three-dimensional or animation effects. As a new image making technology, stereoscopic technology is almost a revolutionary breakthrough compared with the traditional plane image technology. Stereo technology is widely used, such as card manufacturing, advertising, film and television, sports, games, fashion, printing and so on. Stereo technology can be used in all fields that can involve image applications. A series of new stereoscopic products such as stereo photo, stereoscopic printing, stereoscopic advertising, stereoscopic packaging and various stereoscopic business cards were born. Under the background of modern fierce commercial competition, stereoscopic images with strong visual impact have become one of the most powerful tools for photography, advertising, printing and other industries to seek new economic growth points. It can be predicted that stereoscopic technology will usher in an unprecedented development situation. Through the processing of this technology, ordinary plane paintings can be transformed into three-dimensional pictures with overlapping, different scenery, distinct layers, vivid objects and vivid images, giving people an immersive feeling ...

Question 4: What does grating ossd mean? Pin wires connected to the module points.

Question 5: What is a reflection grating, also known as a short-period grating or a weak grating? This grating is characterized by the mutual coupling of light modes in different propagation directions.

Transmission grating (trans * * * transmission grating), also known as long-period grating or strong grating, is characterized by the mutual coupling of light modes in the same propagation direction.

Question 6: What does grating amplitude mean? Grating amplitude is also called grating thickness. For more details, please refer to the following materials.

Describing a grating is to express its characteristics with specific parameters. Grating parameters mainly include grating density, grating thickness, grating sight distance, grating transmittance, grating deviation value and printing point.

1. Grating density

Grating spacing is the width of grating lines. The density (lip) of grating refers to the number of lenticular lines with the same concave and convex in one inch, which is usually called grating lines. For example, 75-line grating means that 75 lenticular grating strips with the same concave and convex are arranged in parallel within 25.4 mm. The conversion relationship between the number of inch grating lines and the number of millimeter grating lines is:1lip = 25.4 mm. The number of grating lines marked in the market refers to the number of cylindrical mirrors in inches.

2. Grating thickness

Gratings are arranged in parallel on the transparent substrate with equal width and equal distance. Due to the focusing effect of cylindrical lens, the depth of field of the image is formed, and it is required that the grating material has a certain thickness to display the depth of field range. Usually, the focal length of grating with more than 75 lines is 2 ~ 3; The focal depth coefficient of 30~75 line grating is 2 ~ 4; The focal depth field coefficient of gratings below 30 lines is 3~5. The thickness of grating is usually expressed by the thickness of material.

3. Grating sight distance

Grating sight distance refers to the distance between people and grating when observing the best stereoscopic effect of grating picture.

4. Grating transmittance

The transmittance of grating refers to the degree to which the grating passes when visible light irradiates the grating. The higher the light transmittance, the better. When the light transmittance is low, it will cause light refraction, change the line-of-sight level of the raster image and affect the stereoscopic effect.

5. Grating deviation value

When the grating is processed in the factory, there is a certain deviation between the actual grating line number and the factory standard value due to the process of hot pressing and condensation. After the grating line detects the bars, it is necessary to correct the nominal value of the grating. The required error accuracy is 0.000 1.

6. Raster pixel print point (pixel)

The output accuracy of many types of printers or printing machines can not reach the ideal accuracy, which will inevitably lead to the inconsistency between the raster imaging output picture and the raster plate. Therefore, a specific grating is tested on a specific output device (especially a large format printer) and identified by the number of printing points pixels. The conversion relation is: lpixel= printer resolution (dpi)/lpi.

7. Performance indexes of common grating materials

Grating materials have different performance requirements according to different uses.

Question 7: What does a 500-line/mm grating mean? 500 lines /mm is the grating constant, that is, there are 500 light-transmitting slits in1mm.

Question 8: What is a raster image? Raster images are also called bitmaps, bitmaps and pixel images. Simply put, the smallest unit is a picture composed of pixels, with only point information. It will be distorted when scaling. Each pixel has its own color, similar to the picture in a computer. If you enlarge it, you will see that this point is divided into small color blocks. This format is suitable for storing irregular graphics with rich colors, such as photography and scanning. Files in BMP, GIF, JPG and other formats. When they are copied, the drawing software will draw them on the screen or print them out according to the dot matrix in the file.