One of the main lacks of devices of display on the basis of JK-matric is change of a picture at a deviation of a direction of a sight from a perpendicular to the screen. This feature forces to choose very accurately JK-monitor for some kinds of works (for example, preparations of images for printing), and at worst can lead to undue fatiguability, bringing to nothing absence of blinking and harmful radiations. It is necessary to note, that resulted in characteristics of monitors and TVs corners of the review concern to falling contrast (the attitude of brightness of a white field to brightness black) up to a parity 10: or even 5:1, and speak nothing about behaviour of a matrix at small deviations and how vary intermediate (grey) a semitone and a colour rendition.
As an abstract example we shall consider two monitors: the movie summaries the notebook matrix of the first behaves very well at not so greater deviations (for example, down to degrees in one party), but at hardly a greater deviation contrast sharply goes down, whereas the image on the second monitor strongly walks (sharply contrast and a parity between semitones) varies at small deviations, but contrast does not fall below 10: down to direction almost parallel to the screen. From the formal point of view corners of the review of the second monitor will be very much greater, but any user who has worked behind both monitors, will prefer the first, let its passport corners of the review and will be it is less.
Thus, objective testing of devices with JK-matricami should include the characteristic of behaviour of the image at a deviation from a perpendicular to movie summaries the notebook the screen in working and reasonable limits. Contrast at a deviation of degrees (full 160) and more has no value. That at testing JK-matric to reduce a human factor, we have aimed to create the device measuring brightness of the screen under various corners.
Before to pass to the description of evolution of our devices, we shall afford two deviations. First, uprosch'enno it is possible to explain the reason of such behaviour JK-matric to that light from lamps of illumination, reaching eyes of the observer, passes (or nearly so does not pass) through three polarizing filters (top, bottom and, actually, a layer of liquid crystals), and these filters are the most effective work in a perpendicular direction. Whereas in E`LT-trubkah bombarded e`lektronami lyuminofor radiates light in all directions directly from a surface (let even return) the screen. Secondly, all not so is bad. The majority modern JK-monitorov and JK-televizorov are equipped by good matrixes (that does not prevent to be convinced once again of it) movie summaries the notebook and only portable devices, for example, noutbuki and DVD-pleery' with the screen, frequently have the matrixes, described very narrow range of corners.
In the centers of development and certification JK-matric for definition of corners of the review are used uzkonapravlenny'e (the angular size of a measured platform of degrees and less) yarkomery'-fotometry' type TOPCON BM-5A by cost a little kilobaksov.
To buy such device dearly, and to collect even more dearly. Besides the similar registrar would demand the stationary stand, and it would be desirable to use something mobile, compact and easy. Been going to go on compromises, we have decided to try to collect installation from accessible at the price of and simply accessible components. So, it was required to make, first, uzkonapravlenny'y the photogauge, and, secondly, the mobile stand for fixing the gauge in a working range of corners.
For restriction of a corner of sight of the gauge we planned to use the elementary odnolinzovy'y an objective with svetozasch'itnoy blendoy which movie summaries the notebook should focus light from a small platform of the screen on a photodetector. As the last we have taken little bit modified photodetector from the device developed by us for definition of time of the response. Photo diode BPW20RF have replaced with version BPW21R with the built in optical filter approaching spectral sensitivity of the photo diode to sight of the person. OU AD8 have replaced with microcircuit AD7 with a bipolar feed and hardly the best characteristics, and factor of strengthening have raised by means of T-obraznogo connections of resistors. The photogauge without the case and already in the case Despite of all shifts, sensitivity of a photodetector hardly sufficed for registration of light radiated by small site JK-matricy', showing a black field. To increase the light stream getting on the photo diode, keeping thus a narrow orientation of the gauge, in a tube movie summaries the notebook before a focusing lens we have densely inserted some thin tubules from zachernennoy papers. As a result we have received uzkonapravlenny'y (a corner of sight approximately degrees) the compact gauge measuring brightness of a surface in a range from tenth up to, approximately, 4 kd/m (without the additional filter, according to calibration by means of) thus for surfaces in width more than sm make a working corner of a deviation not less than degrees.
The photogauge in gathering with a tube Translation of an analog signal of the photogauge and data transmission into a computer for the subsequent processing is carried out by means of the external block, it is good itself recommended at work in structure of a complex for measurement of time of the response. The same block develops a bipolar feed (+/-15) for OU the photogauge.
The given photogauge is applied both to research of corners movie summaries the notebook of the review, and for definition of uniformity of white and black fields and the average contrast, and also for research of high-speed characteristics of a matrix according to the developed technique, which
The first version of the stand fixing the gauge under the necessary corner, represented the rectangular basis and sharnirno the framework fixed on it with the photogauge which fixed reyka with apertures.
Simplicity - the mortgage of reliability At measurement of corners of the review this support is put on the matrix located horizontally, and then the gauge is fixed under the certain corner and measurement of brightness of fields of various intensity is made. Further the gauge is fixed under a following corner, measurements repeat, etc. Fields on the screen are deduced by means of the special program, it registers the response and spends averaging indications. Testing is spent in the blacked out premise to eliminate influence of an extraneous flare. During measurements, except for black and white water, brightness of three grey fields 25, and % on a scale grey (not in %% from relative brightness is measured!), Where white there correspond 1 %, black %. Despite of the simplicity, movie summaries the notebook the given installation allows to receive dependences of brightness of fields and contrast from a corner of an inclination on which it is possible to define how brightness and contrast quickly falls at a deviation from a perpendicular, at what corners there is a merge of semitones, etc. During enough long time this installation was used basically for testing matrixes noutbukov.
However two circumstances did not give rest: first, during tests it was necessary to change times position of a framework with the gauge ( fixed corners and directions: to the right, to the left, upwards and downwards), and, secondly, the step on corners was enough greater, and to reduce it, means, to complicate work of the operator even more. The obvious decision of this problem – to raise a degree of automation.
It has most difficultly appeared to create compact, operated by the program on a computer, a drive turning a framework with the gauge. The first and unsuccessful attempt was a design from two polovinok the phonograph records, fixed on ramke-osnovanii, thus the framework with the gauge should move by means of two rubber rollers, sliding to that was movie summaries the notebook an edge of a product aprelevskogo a factory. Rollers rotated motorchikom with a reducer. Basically, all this even somehow rotated and moved, but after at attempt to drill an aperture for the gauge of a corner, the piece of a plate has broken away, vinylic semicircles have been replaced duralumin, to which rollers did not cling. It was necessary to think out other drive.
The first version of the mechanized installation finished to a working condition, moves a framework with the gauge by means of system of blocks and a thread which is reeled up a drum from the film cartridge.
Winds a thread, Sagging a thread drags out is eliminated by action of weight of a framework and the gauge, and in the top dead point an elastic band for denominations. In a drive it is used motorchik and the reducer movie summaries the notebook from a drive of a tray old CD-ROM-diskovoda. Motorchikom operates the driver from TOSHIBA (taken of the same disk drive), a feed and this microcircuit receives commands from module E-140. Extreme positions of the photogauge are defined by means of two trailer closing gauges (too from CD-privoda). Intermediate positions of a mobile framework are detected by the optical gauge (IK-diod - the phototransistor), worked once in NGMD 5-ti-dyuymovogo a format. At movement of a framework this gauge fixes passage of the apertures drilled with certain step on perimeter of one semicircles. Outputs of all gauges are connected to digital (TTL) to inputs of module E-1 which on interface USB is connected to a computer and serves as the intermediary between it and installation. The operating procedure with new installation has remained basically former, only now a cycle of measurements in one direction the program operates, and intervention of the operator at this stage is movie summaries the notebook not required. The operating program moves the gauge on an initial position (the bottom position, measurements are conducted at moving the gauge upwards, to a perpendicular to the screen), displays the next field, gives out a command on moving of the gauge upwards, registers the response of the gauge and passage of angular labels, makes interpolation of intermediate values of corners, etc., will not be settled yet the list of semitones.
The dialogue window of the operating program All is good, but pre-production operation (proceeding till now) has revealed a number of constructive lacks. First, the optical gauge of angular labels works astably – is eliminated by addition of the transistor or connection of an output of the gauge to an analog input of module E-140. Secondly, installation has turned out bulky, at measurement of matrixes of the small size it should be put on a framework of the screen, and to test matrixes noutbukov which do movie summaries the notebook not lean back on 1 degrees, it will not turn out – dimensions can be reduced, having transferred unit with motorchikom and a drum and having truncated ramku-osnovanie. Thirdly, the drive demands very accurate reference as it is necessary to touch casually a mobile framework as the thread flies from blocks then it is necessary to interrupt work and accurately to stack a thread on a place. Last lack can be eliminated, only essentially having changed a drive.
In the following version of installation, free from listed above lacks, the step-by-step engine (SHD) from 5-ti-dyuymovogo flopovoda with the screw fixed on an axis on which the nut moves, sharnirno fixed on a framework is used. So rigid fixing of position of a mobile framework with the photogauge concerning the basis is reached.
To operate work SHD it is more complex, than single-phase collector movie summaries the notebook motorchikom. The elementary scheme supervising SHD, consists of two blocks: the driver switching windings, and the controller generating operating impulses. The driver can be collected from discrete elements or, that is easier, to use specialized microcircuits. The same raspotroshenny'y 5-ti-dyuymovy'y the disk drive has given all in our order mikroshemu-drayver from Hitachi. Basically, as the controller block ATSP E-1 could serve. Unfortunately, this inexpensive device does not allow to load into it and to execute the user microprograms, therefore it should to generate operating sequence by means of the program started on a computer, and to transfer it on USB-interfeysu, and without that loaded by the dataflow from the photogauge. The external controller was required.
Stocks of microcircuits of 155-th series provoked to collect the controller from them. Basically all is simple: the clock generator, which frequency it is possible to set the movie summaries the notebook variable resistor, plus logic on pare-troyke microcircuits, on a command forming two sequences of impulses shifted on a phase and providing a reversive mode. However trial tests of the similar decision have revealed the big consumption (up to 1 mA), that for the device eating from USB, is not welcomed. Certainly, it was possible to get modern economic logic microcircuits for copecks but if all the same to go to shop, whether that to buy one mikroshemu-mikrokontroller is easier and to collect controller SHD on it? Not easier, but it is more interesting. Besides the device on the microcontroller gives in to improvement is easier and adaptations to new obvyazke – to change the microprogram enough and to connect alarm lines.
We have chosen PIC16F876A from. On the one hand, functionality of this microcontroller in some times surpasses necessary for management SHD. Basically, having added OU with variable factor of strengthening and, probably, the compiler of interface RS232, it is possible to collect all system of gathering and preliminary data processing without block ATSP E-1 (having movie summaries the notebook simplified it, but also it it is a little having lost thus in accuracy). On the other hand, has reserved a pocket does not pull, and the economy of several tens roubles by individual manufacture has no value.
The program for the microcontroller was written in MPLAB IDE environment, in the same place it was debugged with use of the built in emulator. We stitched PIC16F876A by means of simple low-voltage programmatora, collected on a model payment. On the same payment there were all other elements necessary for check of working capacity of the scheme.
Not aesthetically, but almost without soldering Programmator it is connected to COM-portu a computer. Three applied for a place programmy'-proshival'sch'ika:, and. Numerous attempts podrujit' PonyProg20 with ours programmatorom have not crowned success whereas FPP and IC-Prog have earned without special arrangements. movie summaries the notebook We have stopped on more advanced IC-Prog.
Preliminary tests have shown, that the framework with the gauge moves too slowly, and the rough increase in frequency of operating impulses leads to the miss of steps that is inadmissible. It was required is thin to pick up the maximal frequency at which the engine rotates quickly and in regular intervals. For this purpose two buttons have connected to the microcontroller and mikrodinamik, and in the program have brought respective alterations. During test movement of a framework by buttons it is possible to change frequency of rotation (change of a divider of frequency is accompanied by short squeak), and simultaneous pressing both buttons in a mode of a stop (long squeak) brings the found optimum value of a divider in long-term memory of the microcontroller...
The scheme tested on a model payment has been transferred on textolite and placed in the case.
The controller in gathering Total in controller SHD movie summaries the notebook details from Second-hand are used: CD-ROM-privoda (buttons), the modem (the quartz resonator on MHz, condensers to it and mikrodinamik), parent payments (sockets), kulerny'h and sound loops (sockets). The others or are bought or taken from old stocks.
The general view of installation As well as in the previous version of installation operates all the program started on a computer, it displays a pattern of the tested monitor, gives out commands on moving of the gauge, keeps indications of the gauge and a label of time and watches a condition of trailer switches. After end of a cycle of measurements and partially during pass of the gauge the program carries out preliminary data processing: recalculates indications of the gauge in vol'ty', averages indications of the gauge and translates labels of time in corners. Speed of rotation SHD does not depend on position of a framework and is defined by frequency of work of the microcontroller and a divider of frequency that allows, knowing the parties of the triangle movie summaries the notebook formed by the centers of hinges of a framework, a nut and SHD and time of movement from one extreme position in another to calculate a corner of a deviation of a framework on time which has been last from the beginning of movement. Measurements are conducted both at rise of the gauge, and at lowering.
As an example we shall result results of testing of matrixes of two devices: JK-televizora (the left column) and noutbuka (the right column). The first block of data is received on the first version of the mechanized stand, the second – on the second.
JK-televizor Noutbuk Dependence of brightness of semitones ( % of black, 1 % white) in the center of the screen from a deviation of an axis of the gauge (negative values to the left, positive values to the right) from a normal to the screen in a horizontal plane. Dependence of brightness of semitones movie summaries the notebook ( % of black, 1 % white) in the center of the screen from a deviation of an axis of the gauge (negative values downwards, positive values upwards) from a normal to the screen in a vertical plane. Dependence of contrast (the attitude of brightness of a white field to brightness black) in the center of the screen from a deviation of an axis of the gauge (negative values to the left or downwards, positive values to the right or upwards) from a normal to the screen in vertical and horizontal planes. A green line the attitude 10:1, purple 5:1.
If to bring to a focus only to how matrixes behave at a deviation of a sight from a perpendicular to the screen, it is possible to approve, that matrix JK-televizora good, and a matrix noutbuka bad. We shall discuss more in detail the received schedules.
On horizontal schedules of the TV of brightness of semitones smoothly decrease in a direction to greater corners and are not movie summaries the notebook crossed anywhere, in the center of the schedule for each semitone there is wide enough plateau within the limits of which brightness varies nesil'no. On schedules of a matrix noutbuka such plateaus narrow also are passed by them in abrupt slopes of falling of brightness. The some people of a semitone are crossed, thus dark grey is crossed with black already at and degrees.
Vertical schedules for the TV are little bit worse horizontal, in particular a plateau at tops, especially for a white field at, but all the same in all measured range of a semitone keep a distance and are not crossed. Corresponding schedules for a matrix noutbuka look awfully. The plateau as for light semitones is not present those basically, the maximum of brightness is defined not in a normal to the screen, and it is movie summaries the notebook a little above, besides, the more darkly the semitone, the is more shift upwards. For average semitones in a perpendicular direction the maximal speed of falling of brightness is observed almost. The first crossing of semitones occurs at (!) degrees of a deviation downwards (dark grey and black), the second at degrees of a deviation upwards and are crossed not any there dark grey, almost black, and light grey and white, that is the white background of page merges with light grey elements of management (the button, toddlers, etc.) . That would occur at about l'shih deviations, simply does not give in to the description. That is even at the smallest deviations from a perpendicular to the screen the picture will walk, and a semitone to be inverted. Besides, if to sit close enough to the screen noutbuka the image in the center of the screen and on periphery will strongly differ. Whether it is possible long movie summaries the notebook and to work comfortably behind such screen a question almost rhetorical, the payment for compactness, low e`nergopotreblenie and low cost is those.
Schedules of contrast once again confirm a conclusion concerning matrixes of these two devices. For the TV schedules smooth down to limits of measurements (+/- degrees), and contrast does not fall below 40:1. Contrast of a matrix noutbuka at a horizontal deviation still has a certain similarity of a plateau, but at vertical the top has outlines of sharp peak. Contrast falls up to 10: at and (a horizontal direction) and at and degrees (vertical).
The unique positive moment of bad matrixes – they allow to adjust more precisely the device and to be trained in definition of optimum conditions of measurement. The matrix noutbuka has allowed to reveal a small skew in positioning the photogauge on a mobile framework (approximately 1, degrees). This defect was showed in a small divergence of horizontal schedules on a vertical, in a failure on one branch of the schedule of contrast and in a divergence of corners of a threshold 10: movie summaries the notebook for contrast across (it is obvious, that across the matrix should be isotropic that is behave equally at deviations to the right and to the left). Fastening of the gauge allows to eliminate a skew easily. Besides on vertical schedules on curves black and dark grey it is possible to see horizontal plateaus at a deviation upwards. The reason that brightness of these colors grows so quickly that there was no range ACP. Specially for such matrixes we have prepared one more file of parameters of measurement to avoid similar overlays in the future.
Inexpensive and compact uzkonapravlennogo the photogauge the design is developed for measurement of brightness of radiating surfaces in a wide range on brightness. The gauge also is suitable and for measurements of high-speed characteristics JK-matric.
Two mechanized installations intended for positioning of the photogauge under movie summaries the notebook various corners to a surface are created, whose brightness is defined.
The corresponding software and management on use of all hardware-software complex intended for definition of behaviour JK-matric at a deviation of a sight from a normal to the screen, definitions of uniformity black is developed, white water also contrast and for research of high-speed characteristics JK-matric
It is shown, that characteristics of matrixes essentially differ, and the results received by means of the given complex, allow to raise a level of objectivity at comparison JK-matric.
See also reviews in section Alexey Kudryavtsev (kalexk@ .com) It is published — on March, 13th, 2006
