US 12,493,173 B2
Fixed-focus projection lens module
Wei-Ting Wu, Hsin-Chu (TW); Cheng-Huan Lyu, Hsin-Chu (TW); Ching-Chuan Wei, Hsin-Chu (TW); and Fu-Ming Chuang, Hsin-Chu (TW)
Assigned to Coretronic Corporation, Hsin-Chu (TW)
Filed by Coretronic Corporation, Hsin-Chu (TW)
Filed on Nov. 1, 2022, as Appl. No. 17/978,953.
Claims priority of application No. 202111457913.2 (CN), filed on Dec. 2, 2021.
Prior Publication US 2023/0176342 A1, Jun. 8, 2023
Int. Cl. G02B 13/16 (2006.01); G02B 9/64 (2006.01); G02B 13/00 (2006.01); G02B 13/22 (2006.01)
CPC G02B 13/16 (2013.01) [G02B 9/64 (2013.01); G02B 13/0045 (2013.01); G02B 13/22 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A fixed-focus projection lens module, for projecting an image beam provided by a light valve onto a screen, wherein the fixed-focus projection lens module comprises a lens group and a light-transmitting element, wherein the lens group consists of seven lenses having refractive powers, and the seven lenses are a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the light-transmitting element are arranged in sequence from a screen side to a display side along an optical axis, wherein each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the light-transmitting element has a screen side surface facing the screen side and allowing the image beam to pass through, and a display side surface facing the display side and allowing the image beam to pass through, wherein:
the first lens, the second lens, the third lens, the fourth lens, and the seventh lens respectively have negative, positive, negative, positive, and positive refractive powers; and
the fixed-focus projection lens module satisfies:
1<|OAL/BFL|<2.1,
wherein OAL is a distance from the screen side surface of the first lens to the display side surface of the seventh lens on the optical axis, BFL is a distance from the screen side surface of the light-transmitting element to a display surface of the light valve on the optical axis, and the light-transmitting element is a first optical element with no refractive power located behind the seventh lens along the optical axis from the screen side to the display side.