US 12,345,980 B2
Optical sheet laminate, backlight unit, liquid crystal display device, information equipment, and production method for backlight unit
Hiroaki Ueno, Tokyo (JP); and Chengheng Tsai, Tokyo (JP)
Assigned to KEIWA Incorporated, Tokyo (JP)
Filed by KEIWA Incorporated, Tokyo (JP)
Filed on Jul. 25, 2024, as Appl. No. 18/784,137.
Application 18/784,137 is a continuation of application No. PCT/JP2022/042381, filed on Nov. 15, 2022.
Claims priority of application No. 2022-011688 (JP), filed on Jan. 28, 2022.
Prior Publication US 2024/0377679 A1, Nov. 14, 2024
Int. Cl. G02F 1/1335 (2006.01); G02F 1/13357 (2006.01)
CPC G02F 1/133607 (2021.01) [G02F 1/133603 (2013.01)] 13 Claims
OG exemplary drawing
 
1. An optical sheet laminate built in a backlight unit, comprising:
a plurality of diffusion sheets each having surfaces, at least one of which has a plurality of recesses having a substantially inverted quadrangular pyramid shape; and
a pair of prism sheets layered above the plurality of diffusion sheets and having prism extending directions perpendicular to each other,
wherein:
the plurality of recesses have an apex angle of 95° or more,
the plurality of recesses are arrayed in a two-dimensional matrix, and
a prism extending direction of a lower prism sheet which is one of the pair of prism sheets and is closer to the plurality of diffusion sheets and an arrangement direction of the plurality of recesses on an upper diffusion sheet which is one of the plurality of diffusion sheets and is closest to the lower prism sheet intersect with each other at an angular difference of 30° or less.