Optical: systems and elements – Single channel simultaneously to or from plural channels – By partial reflection at beam splitting or combining surface
Patent
1997-05-29
1999-01-26
Epps, Georgia
Optical: systems and elements
Single channel simultaneously to or from plural channels
By partial reflection at beam splitting or combining surface
359630, 345 7, G02B 2714, G09B 500
Patent
active
058644326
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
a) Field of the Invention
The invention is directed to a device for showing a first image in a second image which is visible through a transparent pane or sheet at which light proceeding from the first image is reflected and which is so arranged that the first image and the second image are detectable by the observer at the same viewing angle.
b) Description of the Prior Art
Devices of this kind can be used in aircraft and automobiles, for example. For this purpose, the second image represents, for example, the surroundings that are visible through the windshield. The first image, e.g., for flight operation, can be symbols which are displayed in the visual range or viewing area of the pilot via the windshield as virtual images serving as orientation aids for take-off and landing. The use of such devices also provides substantial advantages for other vehicles such as automobiles. For instance, by means of the first image, a symbol can be made visible representing the safe distance by which the driver of the vehicle can gage whether he is too close to a vehicle traveling in front of him. In so doing, it is possible to couple the apparent distance of this symbol with speed so that the vehicle operator can monitor whether or not an adequate safety distance is being maintained between him and the vehicle traveling in front of him.
Further, essential information from the display instruments can also be faded into the viewing area of the driver so that the driver has substantially better control over the vehicle than if he had to constantly glance back and forth between the environment and the dashboard, so that operating safety and driving safety are substantially improved.
There are a great many suggested systems for such devices which are also known as "Head-Up Displays" (HUD). From these suggested systems there arises the important fact that, in order to reduce fatigue, the information of the first image, as virtual image, is formed so that no accommodation of the eye is required while the eye is adjusted to distant vision. In order to form an image as a virtual image at a great distance, the object representing the first image, e.g., a liquid crystal display (LCD), is brought between the focal point and the first lens vertex of an imaging system.
Over the past twenty years, a large number of protective rights have been claimed worldwide for HUDs for motor vehicles. In Europe, however, these systems are still in the developmental and testing stage. In this connection, a distinction is drawn between systems with holographic optics and those without holographic optics. An overview of the former systems can be found, e.g., in the article "Holographic Applications in Avionic HUDs", Woodcock and Kirkham, Military Technology Miltech (1985), page 6.
In systems without holographic presentation such as those known from EP-A-0 202 460 or U.S. Pat. No. 4,740,780, imaging optics are either dispensed with entirely or conventional glass optics, e.g., according to GB 2 203 855 A, are used to generate a virtual image by means of an image generator. In the most elementary systems, the information which is displayed as a first image on a hidden LCD is simply projected on the windshield of a vehicle. An advantage in these HUDs consists in that the driver need not change his viewing direction to detect the displayed information; however, in order to read, the driver must adjust his eyes to the short distance to the windshield. The changing accommodation of the eye to distance vision for viewing the surroundings and to the windshield leads to fatigue and accordingly to lowered response time especially in older drivers.
In systems with virtual image display several meters in front of the windshield, the relaxed eye can read the information at any time; unnecessary fatigue is thus avoided. However, due to the reflection of light on the aspherically curved windshield, especially with virtual image display, imaging aberrations occur which must be corrected by specially computed optics. As can be gathered
REFERENCES:
patent: 3533104 (1970-10-01), Habegger et al.
patent: 4740780 (1988-04-01), Brown et al.
patent: 4973132 (1990-11-01), McDonald et al.
patent: 5066102 (1991-11-01), Hirano
patent: 5157549 (1992-10-01), Suzuki et al.
patent: 5162928 (1992-11-01), Tamoguchi et al.
patent: 5194989 (1993-03-01), Ferrante et al.
patent: 5200844 (1993-04-01), Suvada
patent: 5486840 (1996-01-01), Borrego et al.
patent: 5502456 (1996-03-01), Korenaga et al.
patent: 5566025 (1996-10-01), Knoll et al.
patent: 5576886 (1996-11-01), Ferrante
Optoelectronics Devices and Technologies, Jun. 1991, Tokyo, Japan--Article "Miniature Virtual Disply Implement" B. Wells (pp. 155-162).
Epps Georgia
LDT GmbH Co. Laser-Dispaly-Technologie KG
Mack Ricky
LandOfFree
Device for showing a first image in a second image which is visi does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for showing a first image in a second image which is visi, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for showing a first image in a second image which is visi will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1454320