Optical device, image display apparatus and head-mounted display unit

摘要

Disclosed herein is an image display apparatus, including: a light source; and a scanning section adapted to scan a light beam emitted from the light source; the scanning section including (a) a first mirror, (b) a first light deflection section, (c) a second mirror, and (d) a second light deflection section; the second light deflection section including an external light receiving face; the second light deflection section having a plurality of translucent films provided in the inside thereof; the translucent films having a light reflectivity R2 at a wavelength of the light beam which satisfies: R2≦k×{(P2/t2)×tan(ζ2)}1/2 where k is a constant higher 0 but lower than 1, P2 an array pitch of the translucent films, t2 a thickness of the second light deflection section, and ζ2 an angle formed between the light emitting face and the translucent films.

主权项

1. An image display apparatus, comprising:
a light source; and scanning means for scanning a light beam emitted from said light source; said scanning means including (a) a first mirror mounted for pivotal motion around a pivotal motion axis thereof provided by a first axis extending in a first direction and adapted to receive the light beam emitted from said light source and incident thereto, (b) first light deflection means having an axial line extending along a second direction different from the first direction for receiving the light beam emitted from said first mirror and incident thereto at a first incidence angle and emitting parallel light at a predetermined first emergence angle with respect to the second direction depending upon the first incidence angle of the light beam by the pivotal motion of said first mirror, (c) a second mirror mounted for pivotal motion around a pivotal motion axis thereof provided by a second axis extending in a third direction and adapted to receive the parallel light emitted from said first light deflection means and incident thereto, and (d) second light deflection means having an axial line extending along a fourth direction different from the third direction for receiving the parallel light emitted from said second mirror and incident thereto at a second incidence angle and emitting parallel light at a predetermined second emergence angle with respect to the fourth direction depending upon the second incidence angle of the parallel light by the pivotal motion of said second mirror; said second light deflection means including an external light receiving face provided in an opposed relationship to a light emitting face provided in parallel to the fourth direction for receiving external light incident thereto; said second light deflection means having a plurality of translucent films provided in the inside thereof; a light reflectivity of each of said translucent films in a wavelength band other than the wavelength of the light beam being lower than that at the wavelength of the light beam.