Hologram screen and a method of producing the same

• US 6,421,147 B2
• Filed: 07/06/1999
• Issued: 07/16/2002
• Est. Priority Date: 07/07/1998
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Takada, Kenichiro
• Primary Examiner(s): CHANG, AUDREY Y
• Application Number:
  US09/348,009
• Publication Number:
  US 20010046072A1
• Time in Patent Office: 1,106 Days
• Field of Search: 359/15, 359/16, 359/599, 359/1
• US Class Current: 359/15
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 27/0103 comprising holographic elements
• CPC Class Codes: G02B 5/32 Holograms used as optical elements

Abstract

In a hologram screen for reproducing an image based on an output light obtained by scattering and diffusing an image light from an image projector, when a white light (image light) is projected on the hologram screen; and when a distance between two points at optional two points A and B on a surface of the hologram screen is given by 20 cm or less, and a value of the CIE 1976 chromaticity coordinate (u′, v′) at the point A is given by (u′_A, v′_A) and the value of the CIE 1976 chromaticity coordinate (u′, v′) at the point B is given by (u′_B, V′_B); the output light perpendicularly from the surface of the hologram screen has a color distribution in which a color difference Δu′v′ between two points A and B is derived from the following formula (1) and given by 0.06 or less, where, the formula (1) is expressed by,

Δu′v′=[(u′_A−u′_B)²+(v′_A−v′_B)²]^½  (1)

Further, the output light, which is output to a viewpoint defined by the following formula (2) from the surface of the hologram screen, has the color distribution in which a color difference Δu′v′ between two points A and B is derived from the above formula (1) and given by 0.01 or less, where, the formula (2) is expressed by,

H/2L=0.1  (2)

in the formula (2), L is a distance between the viewpoint and a center of the hologram screen, and H is a length of the hologram screen in the direction of the height.

Claims

1. A hologram screen for reproducing an image based on an output light obtained by scattering and diffusing an image light from an image projector, wherein said hologram screen has a haze ratio of between 5 and 60%.