Image sensors and optical devices

Which is a characteristic of an OLED (organic EL) display?

  1. AIt displays images by blocking backlight with liquid crystals
  2. BEach pixel emits its own light, so no backlight is needed
  3. CIt displays images only by reflecting ambient light
Show answer and explanation

Answer: B. Each pixel emits its own light, so no backlight is needed

An OLED display passes current through layers of organic material to make each pixel emit light. Without a backlight, it can be thin, and black is shown by turning pixels completely off, giving high contrast. The transistor circuits that drive each pixel are built on a glass or similar substrate.

Practice this topic Back to topic

More Image sensors and optical devices questions

  1. In the typical four-transistor pixel of a CMOS image sensor, which transistor moves the charge from the photodiode to the floating diffusion?
  2. What is the noise called that appears the same way at the same positions every time because of pixel-to-pixel variation in characteristics?
  3. How does the size of shot noise, caused by statistical fluctuation in the number of photons, relate to the number of signal electrons N?
  4. What is the main purpose of deep trench isolation (DTI), in which deep trenches filled with insulators are formed between fine pixels?
  5. Which material is suitable for photodiodes that receive light in the 1.55 µm band used in optical fiber communication?