SU1187135A1 - Device for automatic focusing of objective - Google Patents

Abstract

DEVICE FOR AUTOMATIC LENS FOCUS, containing an optical transmission system installed in front of the radiation source connected to the outputs of a pulse generator, an optical receiving system installed with the ability to act on one of the photodetector elements connected to the outputs of the logarithmic amplifiers of the shaping channels, each of which is also equipped with An element, and an actuating element mounted to stop movement of the lens, characterized in In order to increase the accuracy of the automatic focusing of the lens, a key connected by an output to the first inputs of the AND elements, an additional AND element whose output is connected to the actuator, and a synchronizing limit switch are inserted into the device, and each formation channel is equipped with a comparator with an adjustable threshold of operation, a delay element and a peak detector, the synchronization limit switch r connected to the input of the switch, and in each channel of the formation the peak detector is switched on ezhdu output of the logarithmic amplifier and the input of the comparator with an adjustable threshold, is connected to the second input of the output AND gate whose output is connected through a delay ele00 ment with one of the inputs additionally e: ementa I. (

Description

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This invention relates to photographs, namely, devices for automatically focusing a lens.

The purpose of the invention is to improve the accuracy of automatic focusing of the lens.

The drawing shows the proposed device for automatic focusing of the lens.

The device comprises an optical transmission system 1 installed in front of the radiation source 2 connected to the outputs of the pulse generator 3, an optical receiving system 4 and an actuating element 5, for example an electromagnet. Optical receiver system 4 is installed with the possibility of acting on one of the elements of the photodetector 6 connected by outputs to the inputs of logarithmic amplifiers of 7 formation channels. At the same time, the actuating element 5 is connected to the power bus 8 and is mounted with the possibility of stopping the movement of the lens 9, and each formation channel is also provided with an And 10 element.

The device also contains a key 11 connected by an output to the first inputs of the elements AND 10 formation channels, an additional element 12, the output of which is connected to the actuating element 5, and a synchronizing limit switch 13. In this case, the synchronizing limit switch 13 is connected to the input of the key 11, and each channel of formation is equipped with a comparator 14 with an adjustable threshold for operation, a delay element 15 and a peak detector 16. In each channel of formation a peak detector 16 is switched on by a log output of a logarithmic signal The unit 7 and the input of the comparator 14 with an adjustable response threshold, connected to the output 52

To the entrance of the element I 10, the output of which is connected through the element 15 of the support with one of the inputs of the additional element I 12.

Auto-focusing of the lens through the proposed device is as follows.

The result of the radiation of the radiation source 2 operating at a frequency due to the pulse generator 3 is focused by the transmitting optical system 1 and, after reflection from the subject, passes through the receiving optical system 4 to the photodetector 6. In this case, the image shift depends on the distance to the subject. The image, which falls on one of the elements of the photodetector 6, forms in it an electrical signal having a radiation frequency. This signal, after amplification by a logarithmic amplifier 7, is fed to a peak detector 16, which selects its maximum value. The peak detector signal 16 is fed to a comparator 14 with an adjustable response threshold. The latter generates a level of logical units, if the signal from peak detector 16 exceeds the threshold level. The level of the logical unit begins to pass on the corresponding delay element 15 through the corresponding element 10 from the moment the lens 9 begins to move, which is determined by the synchronization limit switch 13. After the delay interval defined by this delay element 15, the level of the logical unit affects the actuator 5, stopping lens movement 9.

The use of the invention significantly improves the accuracy of the automatic focusing of the lens.

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Claims (1)

DEVICE FOR AUTOMATIC FOCUSING OF A LENS, containing an optical transmitting system installed in front of a radiation source connected to the outputs of a pulse generator, an optical receiving system installed with the possibility of acting on one of the photodetector elements connected by outputs to the inputs of the logarithmic amplifiers of the formation channels, each of which is also equipped element And, and an actuator mounted with the possibility of stopping the movement of the lens, characterized in that, with In order to increase the accuracy of the automatic focusing of the lens, a key is inserted into the device, connected by the output to the first inputs of AND elements, an additional AND element, the output of which is connected to the actuating element, and a synchronizing limit switch, and each channel of formation is equipped with a comparator with an adjustable threshold, a delay element and peak detector, and the synchronizing limit switch is connected to the key input, and in each channel of the formation of the peak detector is connected between the output logar of the IF amplifier and the input of the comparator with an adjustable threshold, connected by the output to the second input of the And element, the output of which is connected through the delay element to one of the inputs of the additional element I. 1187