monitors

Question 1

what are the original radiology display monitors called

Answer 1

originally cathode ray tube (CRT)

Question 2

what are the radiology display monitors we use now called

Answer 2

liquid crystal display monitors (LCD)

Question 3

how many liquid crystal pixels/cells sandwhiched between 2 pieces of polarized glass

Answer 3

1000s

Question 4

what is the backlight source of LCDs

Answer 4

light emitting diodes LEDs

Question 5

traits of LCDs

Answer 5

• thin and light
• draw much less power than CRTs

Question 6

what are single LC pixel - parallel polarisers

Answer 6

• orderly arranged crystals
• placed between two plates of polarized glass
• coated with transparent electrodes

Question 7

how does light pass in an LC

Answer 7

light passes through from left
- interlayer film polarises light

Question 8

why is there varying voltage in an LC

Answer 8

• alter amount of light allowed through to give a certain grey level for that cell/pixel

Question 9

LCD

Answer 9

liquid crystal display

Question 10

how are LCDs arranged

Answer 10

arranged in a matrix on a glass substrate

Question 11

what does each LC represent

Answer 11

one pixel

Question 12

how many levels of brightness per pixel

Answer 12

256

Question 13

how long is the capacitor in the LCD able to hold the charge for

Answer 13

until next refresh cycle

Question 14

pixel colour filters

Answer 14

• red
• green
• blue

Question 15

how many colours can be made up

Answer 15

16.8 million

Question 16

what lights up LCD

Answer 16

LEDs

Question 17

luminous efficacy for LEDS

Answer 17

HIGH

Question 18

lifetime of LED

Answer 18

50,000+

Question 19

what is resolution

Answer 19

number of pixels demonstrated

Question 20

what is a dot pitch/ pixel pitch

Answer 20

distance between centres of two same colour phosphor dots (0.2 to 0.4 mm)

Question 21

when would you use a larger monitor

Answer 21

for higher resolution

Question 22

what is luminance

Answer 22

brightness of screen or photon energy that reaches the eye

Question 23

what rate does luminance describe

Answer 23

the rate at which light is emitted from surface

Question 24

what is luminance given in

Answer 24

candelas per square metre

Question 25

what does luminance ratio equal to

Answer 25

the maximum luminance to minimum luminance (Lmax/Lmin)

Question 26

grey scale range consumer displays

Answer 26

256 (8 bit)

Question 27

grey scale range medical displays

Answer 27

4096 (12-bit)

Question 28

what has a poor greyscale response

Answer 28

colour displays

Question 29

SMPTE

Answer 29

society of motion picture and television engineers

Question 30

what is the SMPTE test pattern used for

Answer 30

a test pattern that we use in imaging to evaluate our quality of our monitors - required to check SMPTE pattern on a CT on monthly basis

Question 31

SMPTE pattern checks

Answer 31

- the 5% patch within the 0% patch is visible - the 95% patch within the 100% patch is visible

Question 32

why is it important to ensure the patches are visible in SMPTE

Answer 32

you can distinguish between very small changes in grey levels

Question 33

what is luminance uniformity

Answer 33

brightness being completely uniform in all forms of display - ensure no dark spots/ ineligibility of information on screen

Question 34

display screen equipment (DSE) user regulations

Answer 34

- regular breaks - essential use only - specific requirement - no more than 2 hours at a time

Question 35

DSE equipment

Answer 35

- safe, efficient, comfortable - minimal heat + noise - minimal glare - promote good posture - large display

Question 36

DSE workstation

Answer 36

- adjustable screen - keyboard at normal height - keyboard independent of screen - allow comfortable head position - adjustable chair - assess environment if changed - not in contact with uncovered window

Question 37

what considerations do you need to take

Answer 37

- image quality - resolution, luminance and LR, bit depth - physical size/ orientation - viewing distance should be 60cm - hi resolution = larger sizes - aspect ratio - portrait vs landscape - room to work? - how many monitors - cost? - standardise monitors in dept (dont have too many different types) - use - can performance be affected by environment and room lighting? - protective cover or not - QA

Question 38

what does pixel size depend on

Answer 38

primary application

Question 39

primary class

Answer 39

diagnostic (reporting)

Question 40

secondary class

Answer 40

review (workstation)