US-12625382-B2 - One-way homogeneous beam expanding screen and three-dimensional display device

US12625382B2US 12625382 B2US12625382 B2US 12625382B2US-12625382-B2

Abstract

An one-way homogeneous beam expanding screen ( 20 ) and a three-dimensional display device. The one-way homogeneous beam expanding screen ( 20 ) comprises a lenticular grating ( 22 ) and at least one linear Fresnel lens ( 21 ); the linear Fresnel lens ( 21 ) is located between a projection unit ( 10 ) and the lenticular grating ( 22 ); the linear Fresnel lens ( 21 ) comprises a plurality of tooth-shaped structures ( 211 ) extending in a second direction (x); the linear Fresnel lens ( 21 ) is used for deflecting a light beam emitted by the projection unit ( 10 ) and enabling the deflected light beam to be normally incident to the lenticular grating ( 22 ); a grating line ( 221 ) of the lenticular grating ( 22 ) extends along the second direction (x); the lenticular grating ( 22 ) is used for uniformly expanding a light beam emitted by the linear Fresnel lens ( 21 ) along a first direction (y), wherein the first direction (y) intersects with the second direction (x).

Inventors

Zengxiang Lu

Assignees

Faith Billion Technology Development Limited

Dates

Publication Date: 20260512
Application Date: 20210303
Priority Date: 20200807

Claims (20)

1 . A three-dimensional display device comprising: a rotary table rotating around a central axis of the rotary table, wherein the central axis extends in a first direction at least one light pole fixed on the rotary table, wherein the at least one light pole comprises a plurality of projection units, wherein each projection unit of the plurality of projection units is arranged to emit light in at least two directions in a plane perpendicular to the first direction to form at least two viewpoints: and a plurality of screens for unidirectional beam homogenizing and expanding, wherein the plurality of screens are arranged to expand, along the first direction, beams of light with different angles of emergence emitted by the plurality of projection units, with propagation direction along the second direction, wherein each screen of the plurality of screens comprises a lenticular grating and a plurality of linear Fresnel lenses, wherein each linear Fresnel lens of the plurality of linear Fresnel lenses is positioned between at least one projection unit of the plurality of the projection units and the lenticular grating, wherein at least one linear Fresnel lens of the plurality of linear Fresnel lenses comprises a plurality of tooth-shaped structures extending along the second direction, and the at least one linear Fresnel lens is arranged to deflect the beams of light emitted by the at least one projection unit to cause the deflected beams of light to enter into the lenticular grating, wherein one or more grid lines of the lenticular grating extend along the second direction, and the one or more grid lines of the lenticular grating is arranged to expand the beams of light from the at least one linear Fresnel lens along the first direction, wherein at least two linear Fresnel lenses of the plurality of linear Fresnel lenses are arranged along the first direction, wherein the plurality of screens for unidirectional beam homogenizing and expanding are positioned on emergent optical paths of the plurality of projection units, wherein the at least one projection unit comprises a first vector pixel, a second vector pixel and a third vector pixel arranged along the first direction; wherein the plurality of linear Fresnel lenses are in one-to-one correspondence with the plurality of projection units, and a center of the second vector pixel is positioned at the same height as a center of the at least one linear Fresnel lens corresponding to the at least one projection unit where the second vector pixel is positioned.
2 . The three-dimensional display device of claim 1 , wherein the projection unit is arranged at a focal point of the at least one linear Fresnel lens.
3 . The three-dimensional display device of claim 1 , wherein the projection unit is arranged on a focal plane of the at least one linear Fresnel lens, and a distance h between the projection unit and a focal point of the at least one linear Fresnel lens satisfies: h ≤ L · tan ⁢ φ - θ 2 ; wherein L represents a focal length of the at least one linear Fresnel lens, φ represents an actual beam expansion angle of the three-dimensional display device along the first direction, and θ represents a desired viewing angle along the first direction.
4 . The three-dimensional display device of claim 1 , further comprising a support lens positioned on one side of the lenticular grating facing away from the projection unit, wherein the support lens is arranged to support the at least one linear Fresnel lens and the lenticular grating.
5 . The three-dimensional display device of claim 4 , wherein one side of the support lens close to the projection unit is a first surface, the first surface is a curved surface, the lenticular grating is attached to the first surface of the support lens, and the at least one linear Fresnel lens is attached to one side of the lenticular grating facing away from the support lens.
6 . The three-dimensional display device of claim 4 , wherein the support lens is an iso-thickness lens or a cylindrical concave lens.
7 . The three-dimensional display device of claim 1 , wherein the at least one linear Fresnel lens and the lenticular grating are in a form of an integrated diaphragm, the tooth-shaped structures of the at least one linear Fresnel lens are positioned on a surface of one side of the integrated diaphragm close to the projection unit, and the lenticular grating is positioned on the surface of one side of the integrated diaphragm facing away from the projection unit.
8 . The three-dimensional display device of claim 1 , comprising a first medium layer, a second medium layer and a third medium layer sequentially stacked, wherein the first medium layer is positioned on one side of the second medium layer close to the projection unit, and the first medium layer and the third medium layer both have a greater index of refraction than the second medium layer; an interface between the first medium layer and the second medium layer is provided with the tooth-shaped structures of the at least one linear Fresnel lens, the interface between the second medium layer and the third medium layer is provided with the lenticular grating, and a surface of the third medium layer facing away from the second medium layer is a plane.
9 . The three-dimensional display device of claim 8 , wherein the first medium layer and the third medium layer have the same index of refraction.
10 . The three-dimensional display device of claim 1 , comprising a fourth medium layer and a fifth medium layer arranged in a stacked manner, wherein the fourth medium layer is positioned on one side of the fifth medium layer close to the projection unit, and the fifth medium layer has a greater index of refraction than the fourth medium layer; a surface of one side of the fourth medium layer close to the projection unit is provided with the tooth-shaped structures of the at least one linear Fresnel lens, an interface between the fourth medium layer and the fifth medium layer is provided with the lenticular grating, and a surface of the fifth medium layer facing away from the fourth medium layer is a plane.
11 . The three-dimensional display device of claim 1 , wherein one pixel in the projection unit has a spot width of d 1 along the first direction on the three-dimensional display device, the lenticular grating has a grating constant of d 2 , and d 1 ≥3d 2 .
12 . A three-dimensional display device comprising: a rotary table rotating around a central axis of the rotary table, wherein the central axis extends in a first direction; at least one light pole fixed on the rotary table, wherein the at least one light pole comprises a plurality of projection units, wherein each projection unit of the plurality of projection units is arranged to emit light in at least two directions in a plane perpendicular to the first direction to form at least two viewpoints; a plurality of screens for unidirectional beam homogenizing and expanding; and further comprising a curved mirror, wherein the curved mirror is positioned between the at least one light pole and the plurality of the screens for unidirectional beam homogenizing and expanding wherein the plurality of screens are arranged to expand, along the first direction, beams of light with different angles of emergence emitted by the plurality of projection units, with propagation direction along the second direction, wherein each screen of the plurality of screens comprises a lenticular grating and a plurality of linear Fresnel lenses, wherein each linear Fresnel lens of the plurality of linear Fresnel lenses is positioned between at least one projection unit of the plurality of the projection units and the lenticular grating, wherein at least one linear Fresnel lens of the plurality of linear Fresnel lenses comprises a plurality of tooth-shaped structures extending along the second direction, and the at least one linear Fresnel lens is arranged to deflect the beams of light emitted by the at least one projection unit to cause the deflected beams of light to enter into the lenticular grating, wherein one or more grid lines of the lenticular grating extend along the second direction, and the one or more grid lines of the lenticular grating is arranged to expand the beams of light from the at least one linear Fresnel lens along the first direction, wherein at least two linear Fresnel lenses of the plurality of linear Fresnel lenses are arranged along the first direction, and wherein the plurality of screens for unidirectional beam homogenizing and expanding are positioned on emergent optical paths of the plurality of projection units.
13 . The three-dimensional display device of claim 12 , wherein the at least one projection unit comprises a first vector pixel, a second vector pixel, a third vector pixel and a color-combining prism, wherein the color-combining prism is arranged to emit rays of light emitted by the first vector pixel, the second vector pixel and the third vector pixel from the same position; wherein the plurality of linear Fresnel lenses are in one-to-one correspondence with the plurality of projection units, and a center of the color-combining prism is positioned at the same height as a center of the at least one linear Fresnel lens corresponding to the at least one projection unit where the color-combining prism is positioned.
14 . The three-dimensional display device of claim 12 , wherein the at least one projection unit comprises one vector pixel; wherein the plurality of linear Fresnel lenses are in one-to-one correspondence with the projection units, and a center of the at least one projection unit is positioned at the same height as a center of the at least one linear Fresnel lens corresponding to the at least one projection unit.
15 . The three-dimensional display device of claim 12 , further comprising a support lens positioned on one side of the lenticular grating facing away from the projection unit, wherein the support lens is arranged to support the at least one linear Fresnel lens and the lenticular grating.
16 . The three-dimensional display device of claim 15 , wherein one side of the support lens close to the projection unit is a first surface, the first surface is a curved surface, the lenticular grating is attached to the first surface of the support lens, and the at least one linear Fresnel lens is attached to one side of the lenticular grating facing away from the support lens.
17 . A three-dimensional display device comprising: a rotary table rotating around a central axis of the rotary table, wherein the central axis extends in a first direction; at least one light pole fixed on the rotary table, wherein the at least one light pole comprises a plurality of projection units, wherein each projection unit of the plurality of projection units is arranged to emit light in at least two directions in a plane perpendicular to the first direction to form at least two viewpoints; and a plurality of screens for unidirectional beam homogenizing and expanding, wherein the plurality of screens are arranged to expand, along the first direction, beams of light with different angles of emergence emitted by the plurality of projection units, with propagation direction along the second direction, wherein each screen of the plurality of screens comprises a lenticular grating and a plurality of linear Fresnel lenses, wherein each linear Fresnel lens of the plurality of linear Fresnel lenses is positioned between at least one projection unit of the plurality of the projection units and the lenticular grating, wherein at least one linear Fresnel lens of the plurality of linear Fresnel lenses comprises a plurality of tooth-shaped structures extending along the second direction, and the at least one linear Fresnel lens is arranged to deflect the beams of light emitted by the at least one projection unit to cause the deflected beams of light to enter into the lenticular grating, wherein one or more grid lines of the lenticular grating extend along the second direction, and the one or more grid lines of the lenticular grating is arranged to expand the beams of light from the at least one linear Fresnel lens along the first direction, wherein at least two linear Fresnel lenses of the plurality of linear Fresnel lenses are arranged along the first direction, wherein the plurality of screens for unidirectional beam homogenizing and expanding are positioned on emergent optical paths of the plurality of projection units, wherein the at least one projection unit is arranged at a focal point of the at least one linear Fresnel lens of at least one screen of the plurality of screens.
18 . The three-dimensional display device of claim 17 , wherein the at least one projection unit is arranged on a focal plane of the at least one linear Fresnel lens, and a distance h between the at least one projection unit and a focal point of the at least one linear Fresnel lens satisfies: h ≤ L · tan ⁢ φ - θ 2 ; wherein L represents a focal length of the at least one linear Fresnel lens, φ represents an actual beam expansion angle of at least one screen of the plurality of screens for unidirectional beam homogenizing and expanding along the first direction, and θ represents a desired viewing angle along the first direction.
19 . The three-dimensional display device of claim 17 , wherein at least one screen of the plurality of screens further comprises a support lens positioned on one side of the lenticular grating facing away from the at least one projection unit, wherein the support lens is arranged to support the at least one linear Fresnel lens and the lenticular grating.
20 . The three-dimensional display device of claim 19 , wherein one side of the support lens close to the at least one projection unit is a curved surface, the lenticular grating is attached to the curved surface of the support lens, and the at least one linear Fresnel lens is attached to one side of the lenticular grating facing away from the support lens, or wherein the support lens is an iso-thickness lens or a cylindrical concave lens.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority to International Application No. PCT/CN2021/078851, filed on Mar. 3, 2021, which claims priority to Chinese Patent Application No. 202010789272.X filed with China National Intellectual Property Administration on Aug. 7, 2020, the contents of which are incorporated herein by reference in their entireties for all purposes. TECHNICAL FIELD The embodiments of the present application relate to the technology of three-dimensional displaying, for example, to a screen for unidirectional beam homogenizing and expanding and a three-dimensional display device. BACKGROUND In the related technology, naked eye three-dimensional displaying can be achieved based on principles such as holographic projection, lenticular gratings, volumetric 3D and integral imaging. In terms of implementation, a lenticular grating uses the refraction effect of the cylindrical lens to present different pictures at different angles, so a three-dimensional visual effect is produced based on the parallax caused by separate left eye's images and right eye's images. In three-dimensional display devices, vector pixels can be used as the image source. The number of vector pixels, thus the costs, can be reduced by using a lenticular grating for unidirectional beam expanding. When beam expanding is performed at a relatively small angle, the beam homogeneity is relatively good. When beam expanding is performed at a required large angle, the peripheral area is less bright than the central area, which leads to an abrupt change in brightness when the image is viewed from one position to another in the direction of beam expanding and thus to inhomogeneous displaying. SUMMARY The embodiments of the present application provide a screen for unidirectional beam homogenizing and expanding and a three-dimensional display device, wherein the screen for unidirectional beam homogenizing and expanding can expand, along the same direction (i.e., a first direction), beams of light emitted by a projection unit into light cones with uniform intensity and same distribution, with propagation direction and angle of divergence unchanged along a second direction, and make rays of light emitted by two projection units have the same brightness after unidirectional homogenizing and beam expanding, avoiding abrupt changes in brightness in spliced images; the screen can improve display brightness and homogeneity when applied to the three-dimensional display device. In a first aspect, an embodiment of the present application provides a screen for unidirectional beam homogenizing and expanding, which is arranged to expand, along a first direction, beams of light with different angles of emergence emitted by a projection unit into light cones with uniform intensity and same distribution, with propagation direction and angle of divergence unchanged along a second direction, wherein the screen for unidirectional beam homogenizing and expanding comprises a lenticular grating and at least one linear Fresnel lens; the linear Fresnel lens is positioned between the projection unit and the lenticular grating;the linear Fresnel lens comprises a plurality of tooth-shaped structures extending along the second direction, and the linear Fresnel lens is arranged to deflect the beams of light emitted by the projection unit to enable the deflected beams of light to be normally incident on the lenticular grating;grid lines of the lenticular grating extend along the second direction, and the lenticular grating is arranged to uniformly expand, along the first direction, the beams of light that exit the linear Fresnel lens;when the screen for unidirectional beam homogenizing and expanding comprises at least two linear Fresnel lenses, the linear Fresnel lenses are arranged along the first direction, and beams of light emitted by two adjacent projection units along the first direction and received at the seam position of two adjacent linear Fresnel lenses form the same distribution after passing through the screen for unidirectional beam homogenizing and expanding;wherein the projection units are in one-to-one correspondence with the linear Fresnel lenses, a perpendicular distance between the projection units and the one-to-one corresponding linear Fresnel lenses is equal to the focal length of the linear Fresnel lens, and the first direction intersects the second direction. In a second aspect, an embodiment of the present application also provides a three-dimensional display device, which comprises: a rotary table rotating around a central axis of the rotary table, wherein the central axis extends in a first direction;at least one light pole fixed on the rotary table, wherein the light pole comprises at least one projection unit, each of the projection units is arranged to emit light in at least two directions in a plane perpendicular to the first direction to form at least two viewpoints; andany one of the screens for unidir