US 11,740,502 B2
External light use type display body
Baku Katagiri, Tokyo (JP); Kentaro Kusama, Tokyo (JP); and Tatsuki Kuramoto, Tokyo (JP)
Assigned to LINTEC CORPORATION, Tokyo (JP)
Filed by LINTEC CORPORATION, Tokyo (JP)
Filed on Mar. 30, 2022, as Appl. No. 17/708,133.
Claims priority of application No. 2021-059398 (JP), filed on Mar. 31, 2021.
Prior Publication US 2022/0317507 A1, Oct. 6, 2022
Int. Cl. G02F 1/1335 (2006.01); G02B 5/02 (2006.01)
CPC G02F 1/133504 (2013.01) [G02B 5/0215 (2013.01); G02F 1/133553 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An external light use type display body comprising:
a light diffusion control layer;
a display layer; and
a reflective layer, wherein
the light diffusion control layer, the display layer, and the reflective layer is laminated in this order or the display layer, the light diffusion control layer, and the reflective layer is laminated in this order,
the light diffusion control layer has a regular internal structure that comprises a plurality of regions having a higher refractive index within a region having a comparatively lower refractive index,
the reflective layer comprises a patterned indented structure when at least one cross section cut in a thickness direction is viewed, the patterned indented structure having a surface that constitutes a reflective surface,
provided that a surface of the external light use type display body on a side distal to the reflective layer is defined as an entrance plane and a plane including a normal line of the entrance plane and a diffusion central axis of the light diffusion control layer is defined as a light ray traveling plane, an angle formed between a light ray traveling on the light ray traveling plane and the normal line of the entrance plane is assigned with a negative sign when the light ray is incident from a main inclination direction side of the patterned indented structure or exits toward the main inclination direction side with reference to the normal line of the entrance plane, while in an opposite case, the angle is assigned with a positive sign,
provided that when a position on the patterned indented structure in the thickness direction of the reflective layer is differentiated, to obtain a differential value, at a position in an in-plane direction of the reflective layer with respect to a cross section of the patterned indented structure obtained by cutting on the light ray traveling plane and an inclination direction of a fine surface in the patterned indented structure is classified in accordance with whether the differential value is a positive value or a negative value, the main inclination direction of the patterned indented structure means a more frequent inclination direction, and
the light diffusion control layer, the display layer, and the reflective layer are configured such that when the entrance plane is irradiated with light rays that travel on the light ray traveling plane with a predetermined incident angle while being scanned along an intersection line of the light ray traveling plane and the entrance plane, 50% or more of the light rays must satisfy at least one of Formula (1) or Formula (2):
θiddd−≤θod≤θdd+  (1)
θdd−≤θid≤θdd+od  (2)
where the θid means an angle of the light ray directed from the entrance plane toward the reflective layer with reference to the normal line of the entrance plane immediately after being incident on the light diffusion control layer and is −35° or −25°,
the θod means an angle of the light ray reflected from the reflective layer and directed toward the entrance plane with reference to the normal line of the entrance plane immediately after being incident on the light diffusion control layer, and
the θdd− and θdd+ are defined as angles of a lower limit and an upper limit of a diffusion angle range of the light diffusion control layer, respectively,
where the θdd− is −38° or more and less than 0°, and the θdd− is equal to or between −13° and 25°.