Title:
SURFACE LIGHT SOURCE DEVICE AND PRISM SHEET
Document Type and Number:
Japanese Patent JP2017027814
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a surface light source device in which light distribution of planar illumination light can be switched into two stages, and which suppresses occurrence of a perceptible light-dark difference in the planar illumination light even in the case of light distribution of a wide emission angle.SOLUTION: A surface light source device 100 includes: light sources 10, 20; a light guide plate 30; and a prism sheet 40 having an incident surface and an emission surface 45 on the light guide plate 30 side, and having a plurality of projected lines 41 extending on the incident surface. The projected line 41 has an inclined surface 41c comprising a first inclined surface 41a and a second inclined surface 41b for forming a bottom part 43 of a groove between itself and the projected line 41 by extending on the adjacent projected line 41 side from an apex 42 of each projected line 41. An inclination angle A1 of the first inclined surface 41a with respect to a normal line 45a of the emission surface 45 is within a range of 35.5°≤A1≤39°, and an inclination angle A2 of the second inclined surface 41b with respect to the normal line 45a is within a range of 23°≤A2≤30°.SELECTED DRAWING: Figure 3
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Inventors:
OKI YOJI
CHIJINAMI KAZUMI
CHIJINAMI KAZUMI
Application Number:
JP2015145843A
Publication Date:
February 02, 2017
Filing Date:
July 23, 2015
Export Citation:
Assignee:
STANLEY ELECTRIC CO LTD
International Classes:
F21S2/00; G02F1/13357
Domestic Patent References:
| JP2005049857A | 2005-02-24 | |||
| JP2006106074A | 2006-04-20 | |||
| JP2013190778A | 2013-09-26 | |||
| JP2013190779A | 2013-09-26 |
Attorney, Agent or Firm:
Creation International Patent Office