What does the projector do?
In terms of the composition of projector products, it includes the three main components of the core projection imaging component, optical engines, electrical control and interface. The core projection imaging components are at the core of projector products, accounting for a very important part of the cost composition of the projector product as a whole and have a status similar to that of a processor in a computer。
The development of projectors has so far been carried out in three main stages of development, each through three typical display techniques, namely, crt projection technology, lcd projection technology and the dlp projection technology developed in recent years。
Crt (cathode ray tube, cathode-ray tube) three-shot projector
As an imaging device, crt achieves the earliest and most widely applied display technology. Crt projector can be said to be the projector's nostrils。
The crt projector, also known as the three-gun projector, works in a way that is no different from the crt monitor, with both the light source and the image. The working characteristics of the crt projector differ substantially from those of the lcd, dlp and other projectors, which, through their own light, divides the input signal sources into the fluorescent screens of the r(r), g(green) and b(blue) crt tubes, where the fluorescent powder glows at high pressure, magnifies, gathers and displays colour images on the large screen。
Crt projector is high in resolution, contrast, colour saturated, compatible with signals, and technically mature. In terms of brightness, the crt projector is much lower, and so far its brightness has hovered. The crt projectors are complex and, in particular, complex and cumbersome, with large body sizes, suitable for installation in a relatively static location with a weaker light. Thus, although there was an early boom in the development of the projector market, the crt projector applications are currently very few and largely exited from the former projector market。
Lcd (liquid crystal display, lcd) projector
Lcd shows that technology is one of the dominant technologies in the current market for projectors, with active liquid crystals and inactive liquid crystals. Inactive liquid crystal reflectors, generally used on laptops, film projectors. And active liquid crystals are photogenic, made into lcd crystals, used on projectors。
Lcd projectors are divided into lcd and lcd valves, and most of our most common projectors are lcd projectors。
A. Lcd projector
The lcd projector produces beautiful images of different greyscale levels and of up to 16. 70 million colours, using the electron effect of lcd to control the penetration and reflection of lcd units by circuit. The lcd projector's light source is a dedicated high-power light bulb with much greater light energy than the fluorescent crt projector, so the lcd projector has a higher brightness and colour saturation than the crt projector。
The size of the lcd crystal plate determines the size of the projector's structure and overall size, and the small size of the lcd crystal board, the smaller the optical system of the projector, the smaller the projector will be。
At present, the market for the lcd projector panels is more than 1. 32 inches (1 inch = 2. 54 cm), 0. 9 inches and 0. 7 inches, supporting the physical resolution of svga and xga. New types of liquid crystal panels, such as 0. 79 inches and 0. 99 inches of high opening, have also begun to be available。
The suppliers of the high-temperature lcd projectile crystal panels are currently the only two japanese producers, epson and sony。
The advantage of the lcd projector is that colour is colourful and bright, and the disadvantage is that the method of projection has some impact on light efficiency, while pixelization is present in the projection image。
The lcd projector can be divided into single- and three-part, with the majority of modern lcd projectors using three-part lcd panels (figure 1). The three-piece lcd projector is a control layer using red, green, blue three lcds as red, green, blue three light, respectively。
The three-piece lcd projector has higher image quality and brightness than the single-form lcd projector. The lcd projector, which is small in size and light in weight, has a simpler manufacturing process, has a higher brightness and contrast and has a moderate resolution, and is currently the most occupied and most widely used projector in the market。
B. Lcd valve projector
The lcd projector uses crt tubes and lcd valves as imaging devices and is the product of a combination of crt projectors and lcd valves. It is the most bright, resolution-highest projector to date and can be as bright as 6,000 ansi currents, with a resolution of 2,500 x 2,000, and is suitable for environmental light and for larger audiences such as the super-large command centre, the conference centre and large entertainment sites, but it is expensive, large and hard to repair. The main brands are hughes-jvc and ambro。
3. Dlp (digital light processor digital light output) digital projector
Dlp technology is a patented technology for tti (texi corporation, united states). Projectors based on dlp display techniques were first found in 1996. The imaging device is dmd (digital micromiror device, digital microscope device). The dmd chip contains thousands of microscopes, each representing a pixel, and the state on or off represents the brightness and darkness of the pixel dot in the image. The beam is projected on the dmd through a high-speed rotation of the colour wheel (discoloration device) and on the large screen through optical lenses. Dlp technology is currently patented by tti, which is also the sole supplier of dmd chips。
A. Technical advantages of the dlp projector
The first is the digital advantage: the introduction of digital technology has made the image contrast, the grey scale (class 256-1024), the colour (2563-10243), the image signal noise ratio, and the image quality stable。
The second is the reflectivity advantage: due to the application of reflective dmd devices, there is a very small distance between microscopes that make up the dlp image pixels, resulting in a light efficiency of over 85 per cent for imaging devices. The images are very bright and very clear。
B. Dlp projectors can be divided into:
Single-piece projector: the advantage of a single-piece dlp projector is that it is light-efficient, contrasted, clearly imaged, especially in terms of black and white images and text, while the size of a single-piece dlp projector can be small and light, with the disadvantage that the colour expression is not real and natural。
Three machines: dlp projectors, made from three dmd chips, can achieve greater brightness and colour, and can be as bright as 10,000 ansi fluent, mostly for special situations such as digital cinemas。
The current lcd and dlp projectors are the two main public camps. The majority of japanese manufacturers use lcd technologies, and european and american producers can use both lcd and dlp technologies. The lcd and the dlp are in fierce competition, and there is no clear answer as to who is better in terms of product, technology, but it is certain that the image of the projector using the dlp is more contrasted, that the optical system is more compact, and thus superior in volume and weight; and that the lcd is strong in terms of brightness, colour and detail. The two technologies, which are unique and difficult to divide, will coexist for a considerable period of time to come, and unless one side makes a breakthrough in technology or market strategy, it is possible to break the balance and dominate。
