Comparing LCD and LED screens

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Date:

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Quick Questions

Shade in the A or B circle for each question.

1. Which backlight does an older LCD screen use?

A An LED backlight

B A fluorescent (CCFL) backlight

2. Which screen is usually thinner?

A LED screen

B LCD screen with a CCFL backlight

3. Which screen normally uses less power?

A LCD screen with a CCFL backlight

B LED screen

4. Which screen usually gives a brighter picture?

A LED screen

B LCD screen with a CCFL backlight

5. Which screen usually has better contrast, such as deeper blacks?

A LED screen

B LCD screen with a CCFL backlight

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1LCD backlight = CCFL		Ascreen = LED
2LED backlight = LEDs		BAn LED screen is lit by LEDs, so it is brighter and has better contrast.
3A thin, light, battery-friendly laptop needs a screen that is slim and uses less power.		Cscreen = LCD
4An older, thicker monitor that uses more power is likely to have a CCFL backlight.		DAn LCD screen is lit from behind by a fluorescent (CCFL) tube backlight.
5LED screen: backlight = CCFL		ELED screens use LED backlights, not CCFL tubes. CCFL is the backlight used in LCD screens.
6LED power use > LCD power use		FLED screens use less power than LCD screens, so the comparison is the wrong way round.

Definitions

LCD vs LED

Fill in the Blanks

Complete each line of code by filling in the missing parts.

lcdBacklight ← ____ ledBacklight ← LED

brightness(LED) _ brightness(LCD)

_____(LED) < power(LCD)

IF portable = TRUE THEN screen ← ___ ENDIF

thickness(___) < thickness(LCD)

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A lcd_backlight = "CCFL"

B led_backlight = "LED"

C led_power = "high"

D lcd_power = "higher"

Question 2

A screen = "LED"

B backlight = "CCFL tubes"

C thin = True

Question 3

A if screen == "LED":

B thickness = "thicker"

C else:

D thickness = "thicker"

Question 4

A screen = "LCD"

B backlight = "CCFL"

C brightness = "lower"

D contrast = "better"

Question 5

A lcd_backlight = "LED"

B led_backlight = "LED"

C print(lcd_backlight)

Answer Key

Comparing LCD and LED screens

Section A: Quick Questions

B — A fluorescent (CCFL) backlight

A — LED screen

B — LED screen

A — LED screen

Section B: Match the Pairs

LCD backlight = CCFL → An LCD screen is lit from behind by a fluorescent (CCFL) tube backlight.

LED backlight = LEDs → An LED screen is lit by LEDs, so it is brighter and has better contrast.

A thin, light, battery-friendly laptop needs a screen that is slim and uses less power. → screen = LED

An older, thicker monitor that uses more power is likely to have a CCFL backlight. → screen = LCD

LED screen: backlight = CCFL → LED screens use LED backlights, not CCFL tubes. CCFL is the backlight used in LCD screens.

LED power use > LCD power use → LED screens use less power than LCD screens, so the comparison is the wrong way round.

Section C: Definitions

LCD vs LED — LCD screens use a fluorescent (CCFL) backlight; LED screens use LED backlights, so they are brighter, thinner, have better contrast and use less power.

Section D: Fill in the Blanks

lcdBacklight ← CCFL
ledBacklight ← LED

brightness(LED) > brightness(LCD)

power(LED) < power(LCD)

IF portable = TRUE THEN
    screen ← LED
ENDIF

thickness(LED) < thickness(LCD)

Section E: Spot the Error

C — LED screens use less power than LCD screens because of their LED backlight. The line should be led_power = "low".

B — An LED screen is backlit by LEDs. CCFL fluorescent tubes are the backlight in an LCD screen. The line should be backlight = "LED lights".

B — LED backlights are small, so LED screens can be thinner than LCD screens. This line should set thickness = "thinner".

D — An LCD screen with a CCFL backlight has lower contrast than an LED screen. The line should be contrast = "lower".

A — An LCD screen uses a fluorescent (CCFL) backlight, not an LED one. The line should be lcd_backlight = "CCFL".