Backlight unit, liquid crystal display module and electronic device

1 . A backlight unit, comprising:

a light guide plate (LGP) having a first edge, a second edge, and a corner incident surface extending from the first edge to the second edge, in which the corner incident surface and extensions of the first edge and second edge define a space; and

at least one light source having a diverging light output at a divergence angle incident at the corner incident surface, wherein the light source is positioned with respect to the corner incident surface such that the light source substantially resides within the space and the diverging light output covers an edge portion of the LGP.

2 . The backlight unit as in claim 1 , wherein the light source is positioned with respect to the corner incident surface such that an edge of the diverging light output is at least parallel to the incident surface or intercepting the incident surface.

3 . The backlight unit as in claim 1 , wherein the light source is positioned with respect to the corner incident surface such that an edge of the diverging light output is at least at an angle intersecting the first edge, defining a dark region in the LGP that is outside the divergence angle.

4 . The backlight unit as in claim 1 , wherein the divergence angle is defined as the angle of spread of light from the light source, within which intensity at a point at any angle and at a distance from the light source is at least 70% compared to the intensity at the same distance along an axis of output symmetry of the light source.

5 . The backlight unit as in claim 1 , wherein the light source comprises a light emitting diode (LED).

6 . The backlight unit according to claim 1 , wherein the LGP comprises a pair of corner incident surfaces along the first edge.

7 . The backlight unit according to claim 6 , wherein the LGP further comprises an incident surface along the first edge, to which another light source is incident.

8 . The backlight unit according to claim 3 , wherein the light source has a light-emitting axis perpendicular to the corner incident surface.

9 . A backlight unit according to claim 8 , wherein the corner incident surface and the first edge has an acute included angle about α 1 degree, and 0<α 1 <30.

10 . The backlight unit according to claim 9 , wherein the light source has a divergence angle of about α 2 degree, and 110<α 2 <120.

11 . The backlight unit according to claim 10 , wherein the dark region has an area about ½*(l/2−l 1 cos α 1 ) 2 {cos[α 1 −(π−α 2 )/2]*sin[α 1 −(π−α 2 )/2]+sin 2 α 1 −(π−α 2 )/2tan[(π−α 2 )/2]}.

12 . A liquid crystal display module, comprising:

a backlight unit as in claim 1; and

a liquid crystal display panel positioned relative to the backlight unit.

13 . An electronic device, comprising:

a liquid crystal display panel as in claim 12; and

a control circuitry operatively coupled to the liquid crystal display module to control display of an image in accordance with image data.