Display screens

DISPLAY SCREENSDISPLAY SCREENS

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INTRODUCTIONINTRODUCTION

The aim of this unit is to raise secondary school students’ awareness of the right usage of display screens, mainly computer screens and other computer devices.

Health problems related to computers.

Problems related to working posture

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•Most common health problems when using computers have to do with work-related Musculoskeletal disorders such as back, neck, head and shoulder pain. In addition to this, sedentary habits and long time exposure to computer cause problems, too.

•Using an improper chair and wrong position of hand and wrist cause health

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OCCUPATIONAL HEALTH PROBLEMS OCCUPATIONAL HEALTH PROBLEMS RELATED TO WORKING POSTURES.RELATED TO WORKING POSTURES.

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OCCUPATIONAL HEALTH OCCUPATIONAL HEALTH PROBLEMS RELATED TO PROBLEMS RELATED TO WORKING POSTURES.WORKING POSTURES.

Musculoskeletal disorders (MSDs)Musculoskeletal disorders (MSDs)

Tension neck syndromeTension neck syndrome: is caused due to the static and lateral movement and also stiffness of the neck The user must ensure proper height.

Shoulder and upper back pain:Shoulder and upper back pain: are caused when using a wrong chair such as armless chairs which do not allow arm resting or wrong size of the desk which leave small room to work with the mouse or the keyboard. The improper height of the desk also produces muscle pains.

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OCCUPATIONAL HEALTH PROBLEMS OCCUPATIONAL HEALTH PROBLEMS RELATED TO WORKING POSTURES.RELATED TO WORKING POSTURES.

• BackBack pain pain:: it is important to have workstations that are well designed and have back supported when sitting at the edge of the chair which also enables users back movements.

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• Hand and wrist pain.Hand and wrist pain. When wrists are held at their extremes, flexed or twisted for long period of fatigue put pressure on other muscles and lead to problems.

• Other parts of the body Other parts of the body affectedaffected: long hours sitting on improper chair can make the computer user suffer from lower limbs numbness.


Recommendations for workstations:Recommendations for workstations:

Gyratory base with five arms and Gyratory base with five arms and wheels chairwheels chair

Chair seat and back rest padded. Chair seat and back rest padded.

Seat height: Seat height:

Right chair sizeRight chair size

Chair armsChair arms

Backrest seatingBackrest seating

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Recommendations for desks:Recommendations for desks:

Ensure that the user has sufficient space to place Ensure that the user has sufficient space to place the frequently used items like keyboard, mouse, and the frequently used items like keyboard, mouse, and monitor directly in front of you to avoid awkward monitor directly in front of you to avoid awkward neck and back postures.neck and back postures.

The standard size for office desk is those designed The standard size for office desk is those designed with a width of 160 centimetres and a depth of 80 with a width of 160 centimetres and a depth of 80 centimetres. centimetres.

For workers spending long hours, big office desk For workers spending long hours, big office desk surfaces are recommended.surfaces are recommended.

Adjust monitor in front of your face. Adjust monitor in front of your face.

Use a document stand.Use a document stand.8

COMPUTER-RELATED HEALTH COMPUTER-RELATED HEALTH ISSUES.ISSUES.

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The monitor.The monitor.

The keyboard.The keyboard.

The mouse.The mouse.

CPU and peripheralsCPU and peripherals

Computer software.Computer software.

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The monitorThe monitor

General recommendations:General recommendations:

The monitor must be independent form the CPU and the keyboard.

Monitor position adjustment.

Proper size according to the task.

Adjustment of brightness and glare.

Proper colour combination to avoid discomfort.

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The keyboardThe keyboard


The keyboard must be separated from the screen keyboard must be separated from the screen and the CPU. and the CPU.

Keyboard slope adjustmentKeyboard slope adjustment

ArmrestArmrestFinish surfaces and separated alphabetic and Finish surfaces and separated alphabetic and numeric keypads.numeric keypads.

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The MouseThe Mouse


Being large enough to support the natural Being large enough to support the natural arch/curve of the hand. arch/curve of the hand.

the best mouse should have reasonably flat shape the best mouse should have reasonably flat shape to avoid excessive wrist extension and sufficient to avoid excessive wrist extension and sufficient size, shape and surface texture to prevent the hand size, shape and surface texture to prevent the hand slipping during use.slipping during use.

its shape must allow a full range of movement .its shape must allow a full range of movement .it is advisable to adjust speed and sensitivity in it is advisable to adjust speed and sensitivity in relation to the resulting cursor movement so they relation to the resulting cursor movement so they are synchronized. are synchronized. Encourage computer users to clean their pointing Encourage computer users to clean their pointing devices regularly.devices regularly.

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THE WORK ENVIROMENTTHE WORK ENVIROMENT

Luminance:Luminance:

Luminaries:Luminaries: providing individual task providing individual task lighting such as a desk lamp lighting such as a desk lamp combined with natural light to avoid combined with natural light to avoid reflections.reflections.

Lighting level:Lighting level: An acceptable lighting level may require a compromise between the amounts of light needed to enhance the computer screen visibility and reduce reflections and glare.

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THE WORK ENVIROMENTTHE WORK ENVIROMENT

Glare:Glare:

Direct glare:Direct glare: Glare can result directly from bright light sources that are in the computer user’s line of vision (looking through a window at a bright white wall opposite).

Indirect glare:Indirect glare: it can result from surface or screen reflections. a position in front of the window is inadvisable. The desk should be placed next to it, in a side position. In general, reflections from surfaces within the field of view should be minimized. Colour and finish are used to control the reflectance of a surface.

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THE WORK ENVIROMENTTHE WORK ENVIROMENTAtmospheric conditions:Atmospheric conditions:

Temperature:Temperature: it depends on the season:In summer: 23 to 26º C.

In winter : 20 to 24º C

Humidity: Humidity: perception of temperature also depends on the level of humidity. So if the level of humidity increases, the perception of temperature will be higher. Humans need a relative humidity between 45% and 65% to prevent the mucous membranes in the mouth, nose and eyes drying out.

Speed of air movement:Speed of air movement: it affects both the perception of temperature and the air flow. The uncomfortable perception of coldness from air conditioning system is often produced by a wrong speed air movement from the machine.

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Display screens

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