US 11,747,670 B2
Lighting device
Makoto Hasegawa, Tokyo (JP); Nobuyuki Suzuki, Tokyo (JP); and Masafumi Okada, Tokyo (JP)
Assigned to Japan Display Inc., Tokyo (JP)
Filed by Japan Display Inc., Tokyo (JP)
Filed on Nov. 29, 2022, as Appl. No. 18/70,820.
Application 18/070,820 is a continuation of application No. 17/683,619, filed on Mar. 1, 2022, granted, now 11,537,001.
Application 17/683,619 is a continuation of application No. 17/218,613, filed on Mar. 31, 2021, granted, now 11,294,223, issued on Apr. 5, 2022.
Claims priority of application No. 2020-070754 (JP), filed on Apr. 10, 2020.
Prior Publication US 2023/0087920 A1, Mar. 23, 2023
Int. Cl. G02F 1/1335 (2006.01); G02F 1/03 (2006.01); G02F 1/137 (2006.01)
CPC G02F 1/133526 (2013.01) [G02F 1/0316 (2013.01); G02F 1/137 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A lighting device comprising:
a light guide plate including a main surface and a rear surface,
a reflection sheet disposed at a rear surface side of the light guide, and
a prism sheet opposed to the main surface of the light guide plate,
wherein
the light guide plate is disk shaped, and includes a first hole at a center,
the reflection sheet is disk shaped, and includes a second hole at a center,
the prism sheet is disk shaped, and the prism sheet includes a first prism array opposing to the light guide,
further comprising a reflection mirror set in the first hole of the light guide, and
a light source set in the second hole of the reflection sheet and facing the reflection mirror,
wherein
the light guide plate includes a second prism array on the main surface, and a third prism array on the rear surface,
the first prism array is formed concentrically,
the second prism array is formed radially,
the third prism array is formed concentrically, and
a pitch of the first prism array is larger than a pitch of the third prism array.