公开(公告)号：US5153751A

公开(公告)日：1992-10-06

申请号：US692379

申请日：1991-04-26

申请人： Tomohisa Ishikawa ,  Yoshinori Akamatsu ,  Tsuyoshi Todoriki

发明人： Tomohisa Ishikawa ,  Yoshinori Akamatsu ,  Tsuyoshi Todoriki

IPC分类号： G02B27/00 ,  G02B27/01

CPC分类号： G02B27/0103 ,  G02B2027/0109 ,  G02B2027/0116 ,  G02B2027/0118 ,  G02B2027/012

摘要： The invention relates to a holographic display element which includes a reflection hologram and is attached to, for example, an automobile windshield so as to project light rays carrying images of display information onto the display element from a luminous source in the car. When external light such as sunlight coming is diffracted by the reflection hologram there is a possibility that visible light ranging from 570 nm (greenish yellow) to 780 nm (red) is diffracted into a certain range of angles in a horizontal plane and makes a strange impression on persons viewing the windshield from the outside. According to the invention another reflection hologram having different diffraction characteristics is superposed on the first hologram on the outer side in order that diffraction of visible light into the aforementioned range of angles may become inconspicuous. In one embodiment the second hologram diffracts light of 570-780 nm at angles outside the aforementioned range of angles thereby to prevent undesirable diffraction by the first hologram. In another embodiment the second hologram diffracts different wavelengths into the range of angles so that additive color mixing with visible light diffracted from the first hologram results in whitening of diffracted light or reduction in the excitation purity of diffracted light as viewed outside the vehicle.

摘要翻译： 本发明涉及一种全息显示元件，其包括反射全息图，并且附接到例如汽车挡风玻璃，以便将来自汽车中的发光源的显示信息的图像的光线投射到显示元件上。 当诸如阳光的外部光被反射全息图衍射时，存在从570nm（绿黄色）到780nm（红色）的可见光在水平面中衍射到一定角度范围并产生奇怪的可能性 从外面观看挡风玻璃的人的印象。 根据本发明，具有不同衍射特性的另一反射全息图在外侧叠加在第一全息图上，以便将可见光衍射到上述角度范围内可能变得不显眼。 在一个实施例中，第二全息图以上述角度范围外的角度衍射570-780nm的光，从而防止第一全息图的不期望的衍射。 在另一个实施例中，第二全息图将不同的波长衍射成角度范围，使得从第一全息图衍射的可见光的附加色混合导致衍射光的白化或降低衍射光的激发纯度，如在车辆外部观察的。