| 摘要 |
<p>A light guiding element has a first principal surface, a second principal surface which opposes the first principal surface, a first lateral surface which intersects with the first principal surface and the second principal surface, and a second lateral surface which opposes the first lateral surface. The light guiding element allows light incoming from the first lateral surface to propagate between the first principal surface and the second principal surface. The light guiding element includes a portion in which a refractive index varies substantially continuously from the first principal surface toward the second principal surface.</p> |
