DLP projector

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Quick Questions

Shade in the A or B circle for each question.

1. What does a DLP projector use to form the image?

A A chip covered in thousands of tiny mirrors

B A layer of liquid crystals that block light

2. In a DLP projector, how many mirrors on the chip are used for each pixel?

A One mirror for the whole screen

B One mirror per pixel

3. How does a mirror make a pixel look dark in a DLP projector?

A It tilts away from the lens

B It tilts towards the lens

4. What adds colour to the image in a single-chip DLP projector?

A A layer of colour filters on a touch screen

B A spinning colour wheel

5. Which statement about the DLP chip is correct?

A The mirrors tilt to reflect light towards or away from the lens

B The mirrors stay still while the lens moves to make the image

Match the Pairs

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

Left column		Right column
1DLP projector		AA projector with a chip of tiny mirrors that tilt towards or away from the lens to form the image
2Digital micromirror device (DMD)		BThis describes an LCD projector. A DLP projector uses tiny tilting mirrors on a DMD chip, not liquid crystals.
3A mirror tilted towards the lens makes its pixel bright, and a mirror tilted away makes it dark		CThe chip in a DLP projector that is covered in thousands of tiny mirrors, one for each pixel
4A spinning colour wheel adds colour to the light so the image is shown in full colour		Dlight -> colour wheel -> mirrors -> lens
5DLP projector: uses a layer of liquid crystals to block light for each pixel		Emirror = ON (towards lens) or OFF (away from lens)
6DLP projector: one mirror is shared between many pixels on the screen		FEach pixel has its own mirror. The DMD has one tiny mirror per pixel, not one mirror shared by many.

Definitions

DLP projector

Fill in the Blanks

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

chip ← ___

Number of mirrors per pixel: _

IF mirror is ON THEN light goes to the ____

IF mirror tilts ____, pixel is dark

colour ← light through spinning ____________

Spot the Error

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

Question 1

A chip ← "DMD"

B mirrorsPerPixel ← 100

C colourSource ← "colour wheel"

Question 2

A IF pixel is bright THEN

B mirror tilts away from lens

C ELSE

D mirror tilts away

Question 3

A light ← lamp

B wheel ← still colour wheel

C OUTPUT colour image

Question 4

A FOR each frame

B lamp shines on DMD

C mirrors tilt on or off

D LCD focuses light on screen

E NEXT frame

Question 5

A uses ← []

B APPEND uses, "cinema"

C APPEND uses, "presentation"

D OUTPUT use

Answer Key

DLP projector

Section A: Quick Questions

A — A chip covered in thousands of tiny mirrors

B — One mirror per pixel

A — It tilts away from the lens

B — A spinning colour wheel

A — The mirrors tilt to reflect light towards or away from the lens

Section B: Match the Pairs

DLP projector → A projector with a chip of tiny mirrors that tilt towards or away from the lens to form the image

Digital micromirror device (DMD) → The chip in a DLP projector that is covered in thousands of tiny mirrors, one for each pixel

A mirror tilted towards the lens makes its pixel bright, and a mirror tilted away makes it dark → mirror = ON (towards lens) or OFF (away from lens)

A spinning colour wheel adds colour to the light so the image is shown in full colour → light -> colour wheel -> mirrors -> lens

DLP projector: uses a layer of liquid crystals to block light for each pixel → This describes an LCD projector. A DLP projector uses tiny tilting mirrors on a DMD chip, not liquid crystals.

DLP projector: one mirror is shared between many pixels on the screen → Each pixel has its own mirror. The DMD has one tiny mirror per pixel, not one mirror shared by many.

Section C: Definitions

DLP projector — A projector with a chip of tiny mirrors (one per pixel) that tilt towards or away from the lens to make the image. A spinning colour wheel adds colour.

Section D: Fill in the Blanks

chip ← DMD

Number of mirrors per pixel: 1

IF mirror is ON THEN light goes to the lens

IF mirror tilts away, pixel is dark

colour ← light through spinning colour wheel

Section E: Spot the Error

B — A DLP chip has exactly one mirror for each pixel, so it should be mirrorsPerPixel ← 1.

B — A bright pixel needs its mirror tilted towards the lens so light reaches the screen. It should be 'mirror tilts to lens'.

B — The colour wheel must spin so that different colours pass in turn. It should be 'spinning colour wheel'.

D — The lens focuses the reflected light onto the screen. An LCD is a different type of display technology, so it should be 'lens'.

D — The list is called uses, so the variable name must match. It should be OUTPUT uses.