modern chair design cho máy tính PC Windows

A chair is a piece of furniture with a raised surface supported by legs, commonly used to seat a single person. Chairs are supported most often by four legs and have a back but, a chair can have three legs or can have a different shape. Chairs are made of a wide variety of materials, ranging from wood to metal to synthetic material, and they may be padded or upholstered in various colors and fabrics, either just on the seat as with some dining room chairs or on the entire chair. Chairs are used in a number of rooms in homes e.g. in living rooms, dining rooms, and dens, in schools and offices, and in various other workplaces.

Chairs can be made from wood, metal, or other strong materials, like stone or acrylic. In some cases, multiple materials are used to construct a chair; for example, the legs and frames may be made from metal and the seat and back may be made from plastic. Chairs may have hard surfaces of wood, metal, plastic, or other materials, or some other of these hard surfaces may be covered with upholstery or padding. The design may be made of porous materials, or be drilled with holes for decoration; a low back or gaps can provide ventilation. The back may extend above the height of the occupant's head, which can be optionally contain a headrest. Chairs can also be made from more creative materials, such as cutlery and wooden play bricks, pencils, plumbing tubes, rope, corrugated cardboard, and PVC pipe.

Chair design considers intended usage, ergonomics how comfortable it is for the occupant as well as non-ergonomic functional requirements such as size, stacking ability, folding ability, weight, durability, stain resistance, and artistic design. Intended usage determines the desired seating position. , or any chair intended for people to work at a desk or table, including dining chairs, can only recline very slightly; otherwise the occupant is too far away from the desk or table. Dental chairs are necessarily reclined. Easy chairs for watching television or movies are somewhere in between depending on the height of the screen.

Ergonomic design distributes the weight of the occupant to various parts of the body. A seat that is higher results in dangling feet and increased pressure on the underside of the knees. It may also result in no weight on the feet which means more weight elsewhere. A lower seat may shift too much weight to the

A reclining seat and back will shift the weight to the occupant's back. This may be more comfortable for some in reducing weight on the seat area, but may be problematic for others who have bad backs. In general, if the occupant is supposed to sit for a long time, weight needs to be taken off the seat area and thus "easy" chairs intended for long periods of sitting are generally at least slightly reclined. However, reclining may not be suitable for chairs intended for work or eating at table.

The back of the chair will support some of the weight of the occupant, reducing the weight on other parts of the body. In general, backrests come in three heights Lower back backs support only the lumbar region. Shoulder height backrests support the entire back and shoulders. Headrests support the head as well as are important in vehicles for preventing neck injuries in rear end collisions where the head is jerked back suddenly. Reclining chairs typically have at least shoulder-height backrests to shift the weight of the shoulders instead of just the lower back.