[Home Theater Network HDAV.com.cn] When people choose a projector, regardless of the price, they will carefully compare the performance of different brands of projectors; but when choosing the screen, it is a matter of course. In fact, the quality of the screen determines the pros and cons of the picture.
The position of the projector, the environment, and the material of the screen all affect the effect of the picture. The excellent screen should have four characteristics: wide viewing angle, fine texture, uniform reflection and loyalty to the original color!
Basically, the screen can be divided into three types: diffused, reflective (glass pearlescent) and refractive (pearl):
Diffusion screen
This kind of screen has good diffusibility to the light source, the widest viewing angle and the best performance. Whether the projector is suspended from the ceiling, placed on the table or on the floor, it can display bright and vivid images to satisfy the visual enjoyment of the audience sitting in different positions. Because it has the property of diffusing light, it reduces the impact of external light on the picture. It features soft, comfortable images and rich layers.
Reflective (glass pearl curtain) screen
The characteristic of the reflective screen is to reflect the light source in the same direction. The vertical viewing angle is more restrictive and is more suitable for placing the projector on the floor or on a lower table. Because it reflects the light source more concentrated, so the horizontal viewing angle is also narrow, the audience has to sit in the middle of the screen to see the bright image; the advantage is that the brightness of the projector is not high, the disadvantage is that the viewing position is more limited . In addition, since it reflects the external light back in the same direction, the viewer has to sit on the other side of the light to avoid the influence of external light on the picture.
Refractive (pearl screen) screen
The refracting screen refracts the light source in the opposite direction, with a large vertical viewing angle but a wider horizontal viewing angle, making it suitable for projectors suspended from the ceiling. It will reduce the contrast of light, the image is smoother, and the dark part of the picture is more clearly coordinated. Since the refracting screen refracts the external light to the opposite direction, the viewer has to sit in the same direction of the external light source to avoid the influence of external light on the picture.
There are two factors that affect the visual effects of home theater, namely effective perspective and psychological factors. How to determine the projection screen ratio and the optimal projection distance?
1) Effective viewing angle
In terms of the human visual range, within 10°, the visual acuity area, that is, the central field of view, has the strongest ability to distinguish the color and detail of the image. Information such as graphics can be correctly recognized within 20°, which is called effective field of view. 20 ° ~ 30 °, although the ability to visual acuity and color discrimination began to decrease, but sensitive to activity information, visual acuity decreased at 30 °. However, people have found that if you look at a large picture and the angle of view is large enough, the viewer will feel the same space as the picture, giving people an artistic effect of an immersive presence. Although the image content is two-dimensional, when combined, the flat image can show a three-dimensional effect. This effect makes people feel natural and moving realistic when viewing large images.
2. Psychological factors
Psychological factors also involve the impact on the quality of home theater television images. This is evidenced by a large amount of experimental data, the impact of which is comprehensive. It is related to the number of scanning lines, viewing distance, image aspect ratio, screen size, and spatial field of view. Scanning systems and screen brightness are closely related. Taking definition as an example: when a certain viewing distance, if the viewer feels that the high definition television image in the home theater is much higher than the definition of the conventional television image, then the size of the displayed image becomes smaller. Or the distance between the two images will be far away, and the difference between the two TVs will no longer be easy to detect. So high-definition TV is closely related to the big screen. If its image is displayed on a small screen, its high-definition advantage loses its meaning.
3. Determine the distance between the seat and the screen
The screen is not as large as possible. First measure the distance from the pre-installed position of the screen of the audio-visual room to the seat, and then choose the screen of moderate size, so that the space and equipment can be fully utilized and a home theater can be established. Here is a simple trial algorithm for the distance between the seat and the screen. China Home Theater Network
It is known that the distance between the viewing seat and the screen is D, the unit is cm, and S is the screen size in inches. Screen size is
S=0.164D
This calculation method is based on the viewing angle of 19°. If calculated at a viewing angle of 22°, then
S=0 .2187D
For example, the distance between the seat and the screen is 3 m, the screen size is 0.164 × 300 = 49. 2 inches, and the viewing angle is 19 °. In other words, only a 50-inch rear projection TV is needed. If you want to improve the shock and presence of the picture, the angle of view is 22° (about 4:3 height of the screen × 3 = viewing distance), the size of the screen should be 0.2187 × 300 = 65.6, the need is one Zhang is nearly 70 inches in size.
If you are using a 100-inch screen, the 19° viewing angle should be approximately 610 cm for 100/0.164 and 100/0.2187 ≈ 457 cm for 22° viewing angle. In addition, the visual sense of presence is determined by the size of the perspective, which is certainly not possible with a large screen. If you use a large 120-inch screen and the seats are placed far away from the screen, the effect is better than sitting on a 60-inch screen. Don't think that there is no room for a home theater when the room is small. In fact, using a 50-inch, 60-inch screen in a small space can get enough viewing angles, giving a fairly good visual presence, and much cheaper than using 120-inch, 150-inch projection equipment in a large space. . In addition to having a larger viewing angle and a more realistic view of the screen, if the screen is played on the same type of projection TV, the 60-inch screen is definitely brighter, the picture quality is finer, and the color is more vivid.
Projection screen material
W (White Matte) new white screen
The new white curtain is woven with fine fiber material and has a fine texture. The surface coating balances reflection and absorption of light, with accurate color temperature, natural color and wide viewing angle. The curtains have rich details in the details of the dark lines, and have a good three-dimensional effect to easily cope with the resolution above 720P. In the case of good shading, it can be used well in environments such as walls, ceilings, floors, etc. It is also used in professional audio-visual environments with good light absorption.
WA (White Matte Advance) HD white screen
HD white can be seen as an upgraded version of the new white screen. In addition to all the advantages of the new white screen, it can easily cope with resolutions above 1080P. The WA high-definition white screen material is a screen material with a brightness peak gain of about 0.85 and a viewing angle of 85o (half-value viewing angle). Its base material is glass fiber, which can resist the deformation of the screen caused by the change of temperature and humidity of the environment, and adopts the method of plain woven glass fiber, and the woven texture of the base material is not seen at all on the surface of the curtain. Since the surface is treated with ultrafine particles (ultrafine particles refer to a fine concave and convex design with a diameter of about 30 μm on the surface of the cloth), the image light can be reflected and absorbed flatly, and the contrast and image depth of field are better than those of the conventional white plastic screen. Great improvement.
AM (Gray Matte Advance) light gray screen
The light gray curtain is based on the addition of WA to increase the coating against ambient light. It can absorb the ambient light and light, and has the characteristics of “deep black and film-like color†and diffuse scattering screen. Wide range of features, color temperature, accurate color, natural, rich details, good three-dimensional, easy to respond to 1080P resolution, suitable for use in a better shaded audio-visual environment.
PG (150PG Advance) glass bead curtain
On the basis of WA, an ultra-fine glass bead which can effectively control the reflection of light is added, which can better resist the disordered light of the environment, and make the picture bright and uniform, and the color is gorgeous. The bright picture of the Bead curtain not only makes the image look more vivid, but also helps the elderly who are losing their vision. It is suitable for use in a well-shielded professional audio-visual room or a living room with less light absorption.
AG (Theater Gray Advance)
A gray coating that effectively absorbs clutter is added to the PG. The gray coating is effective against clutter and enhances the depth and detail of the dark spot. The 1.6x gain of the ultra-beads gives the map sufficient brightness and white purity, making the effect black and white, moisturizing, contrast enhancement and enhancement. The sense of layering and three-dimensionality, the mapping is clearer and more meticulous, so that the projected image reaches a new level, creating a cinematic effect with a sense of film.
TB (Theater Sound Adance) through sound screen
The sound-transmitting screen adopts high-density mesh weaving technology, which can effectively eliminate interference fringes, has excellent sound transmission characteristics, can perfectly combine sound and picture, and faithfully reproduce perfect images. This kind of curtain can let the sound pass through without hindrance, so that the position of the theater audio is more reasonable. According to experts, this can change the current visit pattern of the home theater in one fell swoop, so as to create a better sound field and maximize the restoration. The real voice. More fresh and fun home theater information, please pay attention to home theater network (WeChat: cnhifi) http://, the country's most influential home theater audio player interactive media website.
This kind is Low Noise Vacuum Cleaner. This Vacuum Cleaner is airflow control on handle and speed control on unit. It has safety valve to protect motor and double parking positions. It also has automatic cord rewinder and HEPA filter. Its suction power is very high,so you can clean clearly. This one is household vacuum cleaner. Its high suction power can help people clean the house clearly,then the environment will be better. If the air at home becomes better and better,the children will grow up more healthier. I think that's the most important,because children is the future of country.
Low Noise Vacuum Cleaner
Low Noise Vacuum Cleaner, No Noise Vacuum Cleaner, Mini Vacuum Cleaner
Ningbo ChinaClean Household Appliances Manufacture Co., Ltd. , https://www.chinaclean-elec.com