Electric lamp and discharge devices – With temperature modifier – For lead-in-seal or stem protection
Patent
1986-07-28
1990-02-06
Sugarman, Scott J.
Electric lamp and discharge devices
With temperature modifier
For lead-in-seal or stem protection
313371, 313524, 350412, 350464, 350469, 358225, G02B 900, G02B 934, G02B 962, G02B 1316
Patent
active
048984574
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to television equipment and, in particular, is concerned with optical systems for television cameras.
DESCRIPTION OF THE PRIOR ART
Given the world-wide tendency to improve the television picture by attaining better resolution of the optical system of the television camera or of the television tube up to 2125 lines, development of television cameras is presently concentrated on refinement of their optical and electrical parameters.
Known in the art is an optical system of the Volna-801 television camera which is quite popular in the Soviet Union. This optical system comprises, arranged successively downstream of the luminous flux and on one optical axis, an objective lens having n elements, and a faceplate of the television tube, and a light-sensitive layer being located on the last surface of the faceplate relative to the direction of the luminous flux.
This optical system is a four-element objective with a focal length of 15 mm, and a relative aperture of 1:2.8. The TV tube is a half-inch separate-mesh vidicon, electrostatically focused and magnetically deflected. The faceplate of the television tube is a plane-parallel plate.
The disadvantages of this optical system are as follows. The image produced by the optical system of the television camera is of poor quality, and the resolution of the objective in the center of the frame is 400 lines. This optical system cannot, therefore, be used for monitoring precision manufacturing processes, disclosure of fine grain structures, or other tasks which require high resolution of the optical system.
Known in the art is an optical system of a television camera (cf., for example, The Journal of the Institute of Television Engineers of Japan, Vol. 35, No. 3, 1981, p. 3), which comprises, arranged successively downstream of the luminous flux and on one optical axis, an objective having n elements, and a faceplate of the television tube having a light-sensitive layer located on the last surface therof in relation to the direction of the luminous flux.
This optical system is a five-element objective with a focal length of 16 mm and an aperture ratio of 1:1.7. The faceplate is a plane-parallel plate. The television tube is a saticon-type tube with a resolution of 500 lines.
This optical system is deficient in that the television camera equipped with this system cannot produce a high-quality picture, and the optical system cannot, therefore, be used to deal with tasks involving high resolution of the image.
SUMMARY OF THE INVENTION
The invention is to provide a television camera optical system wherein the objective and faceplate of the television tube permit substantial improvement of the television picture produced on the screen.
There is provided a television camera optical system comprising, arranged successively in the direction of the light flux and on one optical axis, an objective having n elements, and a television tube faceplate, a light sensitive layer being located on the last surface thereof in relation to the direction of the light flux. According to the invention, the last, in relation to the direction of the luminous flux, element of the objective has an optical power other than zero and is the faceplate of the television tube.
If the optical system of the television camera is to have a wide field, the last element of the objective is advisable to be made as a concave-flat lens having the concavity thereof facing the object.
It is desirable that, when the field of long focal-length optical systems of television cameras is small and does not exceed 20.degree., the last element of the objective should be made as a positive convex-flat lens having the convexity thereof facing the object.
For long focal-length optical systems of mixed-field television tubes, whose resolution is close to the ultimate, it is advisable that the last element of the objective should be a biconcave lens.
For optical systems having medium fields and operating in television tubes whose resolution is close to the ultimate, it is reaso
REFERENCES:
patent: 2587589 (1952-03-01), Bordewieck
patent: 2917574 (1959-12-01), Toulon
patent: 3194117 (1965-07-01), VanGraafeiland
patent: 3429997 (1969-02-01), Rosner et al.
patent: 3565511 (1971-02-01), Dilworth
The Journal of the Institute of Television Engineers of Japan, 3, vol. 35, No. 3, 1981, p. 3.
Alexeev Viktor N.
Antiropova Irina L.
Lisenko Artemy L.
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