GB1199142A - Method of Determining the Focussing Error of Optical Instruments - Google Patents
Method of Determining the Focussing Error of Optical InstrumentsInfo
- 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
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.
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)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2222666A1 (en) * | 1973-03-19 | 1974-10-18 | Thomson Brandt |
-
1966
- 1966-05-26 GB GB2366266A patent/GB1199142A/en not_active Expired
Cited By (1)
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 |