GB1199142A - Method of Determining the Focussing Error of Optical Instruments - Google Patents

Method of Determining the Focussing Error of Optical Instruments

Info

Publication number
GB1199142A
GB1199142A GB2366266A GB2366266A GB1199142A GB 1199142 A GB1199142 A GB 1199142A GB 2366266 A GB2366266 A GB 2366266A GB 2366266 A GB2366266 A GB 2366266A GB 1199142 A GB1199142 A GB 1199142A
Authority
GB
United Kingdom
Prior art keywords
photo
plane
illumination
focus
cell
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB2366266A
Inventor
Malcolm Atkinson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Steel Company of Wales Ltd
Original Assignee
Steel Company of Wales Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Steel Company of Wales Ltd filed Critical Steel Company of Wales Ltd
Priority to GB2366266A priority Critical patent/GB1199142A/en
Publication of GB1199142A publication Critical patent/GB1199142A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/40—Optical focusing aids

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Microscoopes, Condenser (AREA)
  • Automatic Focus Adjustment (AREA)

Abstract

1,199,142. Photo-electric automatic focusing. STEEL CO. OF WALES Ltd. Aug. 7, 1967 [May 26, 1966], No.23662/66. Heading G1A. In an optical instrument such as a microscope having an illuminating system, the focusing error, that is the displacement of an object from the object plane of the instrument, is determined by sensing the illumination in a plane in the illuminating system and conjugate to the object plane so that as the image of the object goes out of focus in this image plane due to displacement of the object, the level of illumination changes. Fig. 1 shows a compound microscope with a mirror 10 as an object and an illuminating system 13 with a field stop 16. A photo-cell, mounted in an eyepiece or upon a screen is positioned in the conjugate plane B with the field stop 16 either just within the aperture of the field stop or just without, so that as the size of the image of the object changes due to the object moving the illumination of the photo-cell changes. The field stop may be positioned before or after plane B so that the direction of the displacement of the object can be ascertained from whether the illumination of the photo-cell rises or falls. However with the field stop at B two photo-cells may be present so that as the focusing changes their illumination changes in opposite senses; this avoids the influence of light source variations. The two photo-cells may alternatively be placed behind a mask which has two additional apertures to correspond with two small apertures upon opposite sides of a diaphram in another conjugate plane. One aperture of the diaphram is infront of the conjugate plane and the other behind so that when the object is in focus neither aperture is in focus upon the respective of photo-cell, but as the object goes out of focus one or the other aperture comes into focus raising the illumination of the associated photo-cell.
GB2366266A 1966-05-26 1966-05-26 Method of Determining the Focussing Error of Optical Instruments Expired GB1199142A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2366266A GB1199142A (en) 1966-05-26 1966-05-26 Method of Determining the Focussing Error of Optical Instruments

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2366266A GB1199142A (en) 1966-05-26 1966-05-26 Method of Determining the Focussing Error of Optical Instruments

Publications (1)

Publication Number Publication Date
GB1199142A true GB1199142A (en) 1970-07-15

Family

ID=10199271

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2366266A Expired GB1199142A (en) 1966-05-26 1966-05-26 Method of Determining the Focussing Error of Optical Instruments

Country Status (1)

Country Link
GB (1) GB1199142A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2222666A1 (en) * 1973-03-19 1974-10-18 Thomson Brandt

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2222666A1 (en) * 1973-03-19 1974-10-18 Thomson Brandt

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Legal Events

Date Code Title Description
PS Patent sealed
PLNP Patent lapsed through nonpayment of renewal fees