| 摘要 |
PROBLEM TO BE SOLVED: To provide a light guide plate enhancing permeability at an incident angle θ less than a critical angle, and enhancing reflection at an incident angle θ equal to or more than the critical angle.SOLUTION: A light guide plate has a low-reflection film installed on the first surface of a glass plate, and optical means installed on the second surface of the glass plate and configured to suppress light propagating in the glass plate from being radiated from the second surface to the outside. For the light guide plate, when a maximum value of transmissivity of light having a wavelength of 550 nm made incident from the inside of the glass plate toward the first surface within a range of an incident surface θ of 0° to a critical angle is defined as T, and transmissivity of light having a wavelength of 550 nm made incident at the incident angle of 40° is defined as T, the ratio T/Tis 0.7 or more; and when each transmissivity of light having wavelengths of 450 nm, 550 nm, 650nm at the incident angle of 0° is defined as T, T, T, respectively, Tis 96% or more, and difference ΔT between the maximum value and the minimum value among the T, T, Tis 5% or less.SELECTED DRAWING: Figure 3 |
