diopter

/dai'ɔptə/ Cách viết khác : (dioptre) /dai'ɔptə/

Thân thiện

An optometrist uses a diopter to measure a patient's eyeglass prescription.

Definition

1. Noun:
   • A unit of measurement for the refractive power of a lens: A diopter is a unit that quantifies the optical power of a lens or curved mirror. It is defined as the reciprocal of the focal length measured in meters. For example, a lens with a focal length of 1 meter has a power of 1 diopter. A lens with a focal length of 0.5 meters has a power of 2 diopters.

Usage Examples

• Noun:
  • My new eyeglasses have a prescription of -3.5 diopters for nearsightedness.
  • The optometrist explained that a higher diopter number indicates stronger corrective power.
  • A simple magnifying glass might have a power of around 10 diopters.

Advanced Usage

• "Diopter adjustment": A feature on optical devices, like camera viewfinders or microscopes, that allows users to adjust the focus to compensate for their individual eyesight.
  • Before using the microscope, make sure to set the diopter adjustment for your eyes.

Variants and Related Words

• Dioptre (noun): The British English spelling of "diopter".
  • The prescription was written in dioptres.
• Dioptric (adjective): Relating to diopters or refraction by lenses.
  • The dioptric system of the eye focuses light onto the retina.

Synonyms

• Lens power unit: A descriptive synonym for the measurement.
• Refractive power unit: A technical term describing its function.

Related Phrases

• Diopter scale: The marked scale on an optical instrument used for diopter adjustment.
  • Turn the ring until the indicator aligns with your value on the diopter scale.

Học thuật

Noun

1. a unit of measurement of the refractive power of a lens which is equal to the reciprocal of the focal length measured in meters; used by oculists

Từ đồng nghĩa

• dioptre