Color compensation filter

Details Color compensation filter Color compensation filter

1994-05-13

1997-04-29

Callahan, Timothy P.

Optical: systems and elements

Light interference

Produced by coating or lamina

359588, 359589, 362293, G02B 528

Patent

active

056254920

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The invention pertains to a color compensation filter for optical devices comprising observation and photo ray paths, in particular for microscopes. Complex optical devices that, apart from the usual photo ray path, are equipped with an observation ray path may require the correction of color distortions that are caused by the effects of the optical components on the spectrum in connection with the weighting of the color sensitivity of the film material. This can result in color distortions in that part of the ray path directed at the observer (observer ray path) that are different from those of the part of the ray path being used for recording purposes (photo ray path). Such a case involves the correction, or rather compensation, of a combination of color distortions.


BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph of the light tranmission characteristics of a filter according to the present invention;
FIG. 2 is a diagram of light paths in a microscope; and
FIG. 3 shows a section through a color compensating filter according to the present invention.
It is the task of the invention discussed here to insert a compensation filter in the optical ray path of complex devices of this type, which, in turn, allows for selective color compensation in various wave-length areas.
The problem is solved through the use of a color compensation filter which consists of a layered interference filter.


DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates the effect on the spectrum of the layered interference filter system of this invention. A wide, basin-shaped saddle between 470 nm and 580 nm can be seen in the green area. This area of a selected transmission reduction of the color green is responsible for the correction of the color distortion of the color green.
The sharp upswing in FIG. 1 at between 390 and 430 nm--the 50% factor of the transmission is 423.+-.5--is responsible for the reduction of the shorter wave lengths, so that the additional color distortion of the color blue is corrected.
The structure of the component layers as shown in FIG. 3 is outlined in the following chart:


______________________________________ Layer Refractive Index Optical, Thickness t (.lambda. = 500 ______________________________________ nm) 1 n.sub.H = 2.05 0.6630 * .lambda./4 2 n.sub.L = 1.38 0.4700 * .lambda./4 3 n.sub.H = 2.05 2.0773 * .lambda./4 4 n.sub.L = 1.38 0.9616 * .lambda./4 5 n.sub.H = 2.05 0.9722 * .lambda./4 6 n.sub.L = 1.38 0.4910 * .lambda./4 7 n.sub.H = 2.05 0.9722 * .lambda./4 8 n.sub.L = 1.38 0.4910 * .lambda./4 9 n.sub.H = 2.05 0.9722 * .lambda./4 10 n.sub.L = 1.38 0.4910 * .lambda./4 11 n.sub.H = 2.05 0.9722 * .lambda./4 12 n.sub.L = 1.38 0.4910 * .lambda./4 13 n.sub.H = 2.05 0.9722 * .lambda./4 14 n.sub.L = 1.38 0.4910 * .lambda./4 15 n.sub.H = 2.05 0.7495 * .lambda./4 16 n.sub.L = 1.38 0.6179 * .lambda./4 17 n.sub.H = 2.05 0.3019 * .lambda./4 ______________________________________
Layer 1 borders on the medium air (refractive index n=1); layer 17 is on the glass substrate, which has a refractive index n.sub.G between 1.57 and 1.9. The angle of incidence can be between 0.degree. and .+-.10.degree.. H refers to a high refractive substance with a refractive index n.sub.H =2.05, that can vary by a factor of .+-.0.05. The material referred to here belongs to the group zirconium dioxide (ZrO.sub.2), tantalum pentoxide (Ta.sub.2 O.sub.5), hafnium (IV) oxide (HfO.sub.2), or a mixture of metal oxides and rare earth oxides. The material with the refractive index n.sub.L =1.38 is magnesium fluoride (MgF.sub.2).
As is indicated in the chart, the component layers 7/8, 9/10, 11/12 and 13/14 represent identical layers of layers 5/6.
The interference filter discussed here selectively alters the light intensity of the various wave-length areas, so that, for instance, the photomicrographs provide a color-neutral reproduction of the microscopic object. As shown in FIG. 2, the visual observation of an object thro

REFERENCES:
patent: 4145113 (1979-03-01), Ranninger et al.
patent: 4896928 (1990-01-01), Perilloux et al.
patent: 5099359 (1992-03-01), Hrycin et al.

Affiliated with

Also associated with

Rating

Color compensation filter does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Color compensation filter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Color compensation filter will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-710554