Head-up display, a combiner used for the head-up display and a method of designing the head-up display
First Claim
Patent Images
1. A head-up display which comprises:
- an information display source, comprising at least a light source for producing light and a display device for displaying information which is displayed by means of the light; and
a combiner arranged on a windshield glass of a vehicle to diffract the light to an observer in the vehicle;
said combiner including a hologram which has a diffraction spectrum with at least three diffraction peaks, each of said diffraction peaks having a central wavelength λ
, a half width Δ
λ and
a diffraction efficiency η
with respect to the light produced from the information display source and diffracted toward the observer inside the vehicle, said sets of central wavelength, half width and diffraction efficiency having values which cause a color difference between the color tone of the light from the light source and the average color tone of the light reflected from the combiner over the angles of observation to be minimized or which cause the sum of the square of a color difference between the color tone of the light from the light source and the color tone of the light reflected by the combiner to be minimized, wherein each of the three central wavelengths is within one of the ranges of 580-650 nm, 500-570 nm and 420-490 nm, where the color difference is defined to be a color difference Δ
E*ab according to the L*a*b* color system ruled in JIS-Z8730 and is expressed by Δ
E*ab ={(Δ
L*)2 +(Δ
a*)2 +(Δ
b*)2 }1/2 where Δ
L* is the difference of psychometric lightness and Δ
a* and Δ
b* are the differences of psychometric chroma coordinates which causes the color tone of the light from outside the vehicle through the combiner to the observer and the color tone of the light reflected by the combiner to the outside of the vehicles to be close to white.
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Accused Products
Abstract
As a combiner, a hologram prepared by exposure to light is used wherein a combination of the central wavelength λ, the halfwidth Δλ and the diffraction efficiency η of the diffraction spectrum of light minimizes the color difference between the color tone of light from a light source and the color tone in average of reflection light by the combiner, when observed by changing the angle, or the sum of the square of the color differences between the color tone of the light from the light source when observed by changing the angle and the color tone of the reflection light by the combiner. Then, the color tone of the light transmitting from the outside of a vehicle through the combiner, the light being observed by the driver of the vehicle, and the color tone of an outer light reflected by the combiner, the light being observed at the outside of the vehicle, approach a white color in comparison with use of a conventional combiner, whereby a transparent eyesight without any complementary color is given to the driver to thereby increase safety. Further, a head-up display which reduces a change of color even though an observer outside the vehicle looks at the combiner at any angular position and which gives a color tone near a white color, can be provided.
45 Citations
15 Claims
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1. A head-up display which comprises:
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an information display source, comprising at least a light source for producing light and a display device for displaying information which is displayed by means of the light; and a combiner arranged on a windshield glass of a vehicle to diffract the light to an observer in the vehicle; said combiner including a hologram which has a diffraction spectrum with at least three diffraction peaks, each of said diffraction peaks having a central wavelength λ
, a half width Δ
λ and
a diffraction efficiency η
with respect to the light produced from the information display source and diffracted toward the observer inside the vehicle, said sets of central wavelength, half width and diffraction efficiency having values which cause a color difference between the color tone of the light from the light source and the average color tone of the light reflected from the combiner over the angles of observation to be minimized or which cause the sum of the square of a color difference between the color tone of the light from the light source and the color tone of the light reflected by the combiner to be minimized, wherein each of the three central wavelengths is within one of the ranges of 580-650 nm, 500-570 nm and 420-490 nm, where the color difference is defined to be a color difference Δ
E*ab according to the L*a*b* color system ruled in JIS-Z8730 and is expressed by Δ
E*ab ={(Δ
L*)2 +(Δ
a*)2 +(Δ
b*)2 }1/2 where Δ
L* is the difference of psychometric lightness and Δ
a* and Δ
b* are the differences of psychometric chroma coordinates which causes the color tone of the light from outside the vehicle through the combiner to the observer and the color tone of the light reflected by the combiner to the outside of the vehicles to be close to white. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A combiner for a head-up display which is disposed on a windshield glass of a vehicle to diffract light carrying information from an information display source toward an observer in the vehicle, the combiner comprising:
-
a hologram which has a diffraction spectrum with at least three diffraction peaks, each of said diffraction peaks having a central wavelength λ
, a half width Δ
λ and
a diffraction efficiency η
with respect to the light produced from the information display source and diffracted toward the observer inside the vehicle,said sets of central wavelength, half width and diffraction efficiency having values which cause a color difference between the color tone of the light from the information display source and the average color tone of the light reflected from the combiner over the angles of observation to be minimized or which cause the sum of the square of a color difference between the color tone of the light from the information display source and the color tone of the light reflected by the combiner to be minimized, wherein each of the three central wavelengths is within one of the ranges of 580-650 nm, 500-570 nm and 420-490 nm, where the color difference is defined to be a color difference Δ
E*ab according to the L*a*b* color system ruled in JIS-Z8730 and is expressed by Δ
E*ab ={(Δ
L*)2 +(Δ
a*)2 +(Δ
b*)2 }1/2 where Δ
L* is the difference of psychometric lightness and Δ
a* and Δ
b* are the differences of psychometric chroma coordinates which causes the color tone of the light from outside the vehicle through the combiner to the observer and the color tone of the light reflected by the combiner to the outside of the vehicle to be close to white. - View Dependent Claims (8, 9, 10)
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11. A method of designing a head-up display comprising:
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an information display source, comprising at least a light source for producing light and a display device for displaying information which is displayed by means of the light; and a combiner arranged on a windshield glass of a vehicle to diffract the light to an observer in the vehicle; said combiner including a hologram which has a diffraction spectrum with at least three diffraction peaks each of said diffraction peaks having a central wavelength λ
, a half width Δ
λ and
a diffraction efficiency η
with respect to the light produced from the information display source and diffracted toward the observer inside the vehicle, said sets of central wavelengths, half width and diffraction efficiency having values which cause a color difference between the color tone of the light from the light source and the average color tone of the light reflected from the combiner over the angles of observation to be minimized or which cause the sum of the square of a color difference between the color tone of the light reflected by the combiner to be minimized, wherein each of the three central wavelengths is within one of the ranges of 580-650 nm, 500-570 nm and 420-490 nm, where the color difference is defined to be a color difference Δ
E*ab according to the L*a*b* color system ruled in JIS-Z8730 and is expressed by Δ
E*ab ={(Δ
L*)2 +(Δ
a*)2 +(Δ
b*)2 }1/2 where Δ
L* is the difference of psychometric lightness and Δ
a* and Δ
b* are the differences of psychometric chroma coordinates which causes the color tone of the light from outside the vehicle through the combiner to the observer and the color tone of the light reflected by the combiner to the outside of the vehicle to be close to white. - View Dependent Claims (12, 13, 14, 15)
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Specification
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Current AssigneeAsahi Glass Company, Limited (AGC, Inc.)
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Original AssigneeAsahi Glass Company, Limited (AGC, Inc.)
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InventorsHirano, Masahiro, Nakazawa, Norihito
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Primary Examiner(s)HENRY, JON W
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Application NumberUS08/780,218Time in Patent Office734 DaysField of Search359/13, 359/14, 359/22, 359/24US Class Current359/13CPC Class CodesB32B 17/10036 comprising two outer glass ...B32B 17/10761 containing vinyl acetalG02B 27/0103 comprising holographic elem...
