| 摘要 |
<p>PURPOSE: To improve the discriminability of the turning-on/turning-out of a lamp by reflecting the direct light from a bulb by a hologram of reflection type and volumetric phase type without passing the light through a colored filter to increase the diffraction of the prescribed light in the direction of a vehicle behind. CONSTITUTION: A hologram 7b selectively diffracts the red light among the emitted diffused light to achieve the diffracting reflection in the direction of the front surface of an indicating lamp. Because the emitted light is the white light 11, it is necessary to arrange a bulb so as to obtain the angle of incidence where the surface reflected light 15 from the hologram does not reach the indicating surface directly. The bulb is arranged so that the angle of elevationθA,θB of the light source from the points A, B relative to the plane H may satisfy the inequalities 20 deg.<=θA<=tan<-1> (CD/AD) and 20 deg.<=θB<=90 deg. where A is one end of the line segment on the closer side to the light source where the plane S containing the optical axis of the light source and orthogonally intersecting the plane H containing the hologram intersects the hologram, B is the other end on the farther side, C is one end of the line segment on the closer side to the light source where the plane S intersects the light transmitting plate, and D is the intersection of the perpendicular line from C to the plane H with the plane H.</p> |
