Light guide plate and its manufacturing method

1 . A light guide plate having a transparent planar plate, an end face of said planar plate serving as a light incident surface, a principal face of said planar plate serving as a light emitting surface, a principal face opposite to said light emitting surface serving as a light distribution controlling surface, another end face opposite to said light incident surface serving as a counter light incident surface,

wherein a concave pseudo half-spindle type reflection dot is provided in said light distribution controlling surface,

said pseudo half-spindle type reflection dot comprising:

a first curved sloped surface provided on a side of said light incident surface; and

a second curved sloped surface provided on a side of said counter light incident surface against said first curved sloped surface and coupled to said first curved sloped surface,

said first curved sloped surface forming a first circular arc shape viewed from said light distribution controlling surface,

said second curved sloped surface forming a second circular arc shape viewed from said light distribution controlling surface,

said first curved sloped surface forming a third circular arc shape viewed from said light incident surface,

said second curved sloped surface forming said third circular arc shape viewed from said counter light incident surface,

said second curved sloped surface being smaller than said first curved sloped surface.

2 . A light guide plate having a transparent planar plate, an end face of said planar plate serving as a light incident surface, a principal face of said planar plate serving as a light emitting surface, a principal face opposite to said light emitting surface serving as a light distribution controlling surface, another end face opposite to said light incident surface serving as a counter light incident surface,

wherein a convex pseudo half-spindle type reflection dot is provided in said light distribution controlling surface,

said pseudo half-spindle type reflection dot comprising:

a first curved sloped surface provided on a side of said counter light incident surface; and

a second curved sloped surface provided on a side of said light incident surface against said first curved sloped surface and coupled to said first curved sloped surface,

said first curved sloped surface forming a first circular arc shape viewed from said light distribution controlling surface,

said second curved sloped surface forming a second circular arc shape viewed from said light distribution controlling surface,

said first curved sloped surface forming a third circular arc shape viewed from said counter light incident surface,

said second curved sloped surface forming said third circular arc shape viewed from said light incident surface,

said second curved sloped surface being smaller than said first curved sloped surface.

3 . The light guide plate as set forth in claim 1 , wherein a maximum camber of said first circular arc shape is larger than a maximum camber of said second circular arc shape.

4 . The light guide plate as set forth in claim 1 , wherein

θ1>θ2

where θ1 is an angle of said first curved sloped surface against a normal of said light distribution controlling surface; and

θ2 is an angle of said second curved sloped surface against the normal of said light distribution controlling surface.

5 . The light guide plate as set forth in claim 4 , wherein

θ1 is 30° ~89°; and

θ2 is 0° ~60° to less than 90°.

6 . The light guide plate as set forth in claim 1 , wherein a width of said pseudo half-spindle type reflection dot is 5 μm~75 μm.

7 . The light guide plate as set forth in claim 1 , wherein a depth of said pseudo half-spindle type reflection dot is 1 μm~10 μm.

8 . A manufacturing method of the light guide plate as set forth in claim 1 , comprising:

a concave dot metal mold mechanical processing step adapted to form multiple concave dots corresponding to multiple ones of said pseudo half-spindle type reflection dots in a metal mold, to mechanically process a concave dot metal mold.

9 . The manufacturing method as set forth in claim 8 , wherein said concave dot metal mold mechanical processing step uses a cutting tool and a piezoelectric element unit driving said cutting tool.

10 . The light guide plate as set forth in claim 2 , wherein a maximum camber of said first circular arc shape is larger than a maximum camber of said second circular arc shape.

11 . The light guide plate as set forth in claim 2 , wherein

θ1>θ2

where θ1 is an angle of said first curved sloped surface against a normal of said light distribution controlling surface; and

θ2 is an angle of said second curved sloped surface against the normal of said light distribution controlling surface.

12 . The light guide plate as set forth in claim 11 , wherein

θ1 is 30° ~89°; and

θ2 is 0° to less than 90°.

13 . The light guide plate as set forth in claim 2 , wherein a width of said pseudo half-spindle type reflection dot is 5 μm~75 μm.

14 . The light guide plate as set forth in claim 2 , wherein a height of said pseudo half-spindle type reflection dot is 1 μm~10 μm.

15 . A manufacturing method of the light guide plate as set forth in claim 2 , comprising:

a concave dot metal mold mechanical processing step adapted to form multiple concave dots corresponding to multiple ones of said pseudo half-spindle type reflection dots in a metal mold, to mechanically process a concave dot metal mold.

16 . The manufacturing method as set forth in claim 15 , wherein said concave dot metal mold mechanical processing step uses a cutting tool and a piezoelectric element unit driving said cutting tool.