DE1547350C - Comparative photometer - Google Patents

Description

The invention relates to a comparative photometer according to the first additional patent 1 273 854 to the patent 1 260 179, namely according to claim 4 of the first additional patent, d. H. a comparative photometer that matches the User a positive visual indication of both the presence of a predetermined ratio of the Brightness of the two light sources to be compared (comparison) as well as a positive visual display for every deviation from this specified value.

The subject of the patent 1 260 179 is the basic idea of the brightness of two light sources in to compare a common field of vision, the two fixed structure patterns in mutual Has interweaving, each of which is illuminated separately from the light of one of the two light sources and which together define a composite pattern, the configuration of which is in Depending on the brightness of the two light sources is variable, devices for Change in the relative brightnesses of the two light sources are provided and the two patterns one have such a structure that at a given ratio of the brightnesses of the two light sources (Adjustment) a clearly recognizable symbol superimposed on an evenly light background occurs, while deviating from the specified ratio as a result of a confusing Structure of the composite pattern the symbol is not recognizable. There comes the special one Embodiment of the patent L260 179 the formation of the overlay structure by means of two separate carriers in the two beam paths to be compared with physically provided structural patterns come about, for example in the form of blackening structures, polarization structures or Color structures can be executed and each with the light from the one or from the other of the two brightnesses to be compared with one another are illuminated and in a corresponding manner Alignment to each other are kept that the composite pattern is formed when superimposed.

The subject of the first additional patent 1 273 854 is a simplification of the photometer structure, in such a way that that only a physically predetermined structural pattern is required; for this purpose is in accordance with the first additional patent 1 273 854 provided the use of a photometer target, which a has a fixed, low-contrast index symbol on a translucent carrier, which with a pattern having a plurality of permeable spaces and a light reflecting one Material is wasted and from the side facing away from the viewing device with light from the a light source and illuminated by the observation scite is illuminated forth with light from the other light source. In the synchronization state in which the with the light from a light source irradiated through the spaces of the light-permeable carrier provided pattern made of the light-reflecting material as bright as that from the front irradiated with the light of the other light source and this reflecting parts of the reflective Pattern are, then the mentioned (primary) index symbol appears clearly perceptible on a uniformly light, unstructured background, while the (primary) index symbol indicating the adjustment status for all statuses deviating from the adjustment obscured and imperceptible by the pattern structure of the subsurface that then emerges is made.

According to an advantageous embodiment according to claim 4 of the first additional patent 1,273,854 provided that on the translucent support as part of the reflective from the light Material existing pattern a further or secondary symbol is located, which is with all of the given Ratio of the brightnesses (adjustment) deviating states together with that of the first or the primary display symbol imperceptible pattern is perceptible.

According to the exemplary embodiment of the first additional patent 1 273 854, the secondary index symbol is which indicates the unmatched states, in one of the ones by the primary symbol representing the Alignment status indicates superimposed area arranged different area of the reflective pattern. If the illumination of the reflective pattern and / or the Background area or if the reflective pattern in all of its parts this can have the consequence that parts of the underground pattern - and thus possibly also the secondary index symbol - remain faintly visible even in the synchronization state. There . on the other hand, the primary index symbol itself necessarily is carried out in a relatively low average density, can in this case difficulties for the user with regard to the decision about the exact adjustment status result.

The present invention thus relates to a comparative photometer according to claim 4 of the additional patent 1273 854, in which the brightness of two light sources can be compared in a common field of view that is displayed on a translucent carrier in Coverage with a fixed, predetermined, low-contrast primary index symbol ("YES") a multitude discontinuous one with permeable gaps, containing a secondary symbol (»NO«) Shows pattern of a light reflective material, with the support from that of the viewing device opposite side illuminated with light from one light source and from the viewing side with light from the other light source is illuminated and devices for changing the relative brightnesses of the. both Light sources are provided in such a way that at a predetermined ratio of the brightnesses of the two Light sources (alignment) in the field of view the primary symbol on an evenly bright background clearly emerges, while all of them deviate from the specified ratio of brightnesses States along with the pattern making the primary index symbol imperceptible the secondary index symbol is discernible. The present invention aims to achieve the above Problem avoided and generally a comparison photometer of the type mentioned are created at which the accuracy of the light balance achieved is improved by an arrangement which the Blurring and the effective disappearance of what is only clearly perceptible in the balanced state Primary display symbol accelerated even with small deviations from the comparison status.

3 4

For this purpose, according to the invention, FIG. 5 is a view similar to that in FIG

see that the primary index symbol and the second to illustrate the appearance of the target

the index symbol overlapping each other arranged in the photometric comparison between

and that the secondary index symbol overlooks the two light sources,

stored index symbol in a low, middle 5 Fig. 6 a similar representation as in Fig. 4 blackening is carried out. to illustrate the appearance of the target indicator according to the present invention, the screens when the light coming from the scene is separate, the balanced state and the less bright, respectively, than the reference light.
Unbalanced state indicating symbols In Fig. 1, a designated as a whole with 10 is shown overlapping one another in superimposition with a and io comparison photometer, in which the same area of the reflective pattern (of light comparison according to the invention, which the secondary display symbol also uses a target The photometer 10 is part of) are arranged, it is ensured that in connection with two independent light sources in each case in the state in which one of the display 11 and 12 is used, which is visible and clearly perceptible in the following as »scene symbols, es 15 light source "or" reference light source "denotes both perceptibility and recognizability. In detail, the device shown has the following parts: a field line 13, one indistinct and blurred. Even if a diffuser 16, a target 17 and an eyepiece 18 field the structuring of the reflective pattern 20 and a lamp 12. The field of view of the photometer even in the balanced state in some parts faint is determined by the lens 13; this can remain perceptible in form, is formed by the arrangement of a permeable carrier, on the voltage of the two display symbols overlapping one surface of which several lenticular lenses are provided, in any case a clearly exclusive perceptible. The light incident through the lens 13 of the two display symbols only in FIG. 25 falls on the diaphragm device 14; this can be guaranteed from the states represented by them. be conveniently trained; in the example shown

A particularly good result is achieved if it consists of two mutually displaceable plates according to the order in the other additional patent application, which are cut at their edges that lap each other over-P 12 99 904.1 under protection so that one is provided that define the primary index symbol from a photometer aperture 19.
A large number of areas which essentially absorb everything by means of a mechanical coupling 20 between incident light, as well as from a plurality of the two plates, the user can obtain a relative number of areas which essentially cause everything to be displaced between the plates and thus incident light let through, exists. As a result, the size of the diaphragm opening 19 and thus the speckled or speckled appearance of the primary 35 the index symbols incident on the lens 15 and the diffuser 16 in the balanced state is selectively controlled, by means of which the incoming light quantity is controlled. The diffuser 16 can also be designed as a permeable carrier, which could be reliably avoided in terms of positioning accuracy. one surface of which is treated in a special way

The invention also relates to a method for producing a photometer target according to a 40, for example by embossing lens grids, in such a way that incident light when passing through preferred embodiment of the invention; for this purpose the carrier is controlled so that an observer 21 can proceed in such a way that one would see the diffuser 16. if the target 17 were not present, a transparent carrier on one side as a first light source, soft with a thin one photographic layer draws essentially the same over a background area and is defined in this by photographic illumination, which in terms of function and development the primary index symbol is closely related to the average brightness of the scene light source generated with a low, average blackening tone. Details of the photometer, and that one on the developed photographic as well as the optics used, etc., are then not essential for the explanation layer, the secondary symbol containing sion of the present invention; discontinuous pattern of a reflective 50 it is only noted that the light source 11 prints material. a diffuse, essentially uniform background

An embodiment of the invention is illuminated in the base area, the brightness of which by means of the

Drawing shown; in this shows' adjustable diaphragm 14 is selectively controllable.

1 in a schematic perspective illustration between the viewer and the light source 11

Development a photometer according to the present invention 55 a target 17 is introduced; as shown in Fig. 1

dung, borrowed, it has a transparent main support 24

F i g. 2 in a greatly enlarged plan view of a small one on which a primary index symbol 22 is

NEN section from the photo shown in Fig. 1 is seen, superimposed over a reflecting

meter target to illustrate the discontinuous screen 23, which by

Features of the patterns and the 60 areas of opaque white material produced on them are defined

Display symbols, the light from the light source 12 into the

3 shows a section through the target screen reflected along the eye of the viewer 21. In this way

the line 3-3 in Fig. 2, it is ensured that the viewer through the intermediate

F i g. 4 a plan view of the photometer target spaces of the screen 23 through which essentially

screen, as it presents itself to the user, to give uniform light from the light source 11 and, in

Visualization of the appearance when the from the to the same field of view that from the light source 12

The light coming from the measuring scene is brighter than that from the screen 23 which is essentially uniformly illuminated

The light coming from the source is seen. When the background area is lighter than the

If the screen is 23, the screen appears to the viewer 21 dark against a light background; and accordingly the screen 23 appears to the viewer 21 bright against a dark background when the background area is less bright than the screen 23.

In other words, when going through the photometric balance state, there is a reversal the apparent screen brightness instead. In the mentioned adjustment state, which is achieved by selective adjustment the screen device 14 is brought about, the screen 23 and the spaces equally bright between the discrete areas of the screen, and the viewer sees a uniformly lit one Field of view in which the screen 23 is no longer perceived to be clearly distinguishable can be. This represents the ideal situation when each of the reflective areas of the screen is accurate has the same properties, reflects exactly the same amount of light and is uniformly diffuse. Actually it is actually difficult to bring about this condition without considerable care in the Production of the screen on the carrier would be expended. In the practical implementation it arises hence, areas in the viewer's field of view are present where the screen structure is weakly perceptible even in the photometric comparison remains.

For example, the index symbol “YES” serves as the primary display symbol 22 on the target 17, while the screen 23 shows a regular chessboard arrangement with certain areas which form a secondary display symbol “NO” in overlap with the primary index symbol. Of course, however, any other index symbols could be used and the screen could be formed with an irregular or random pattern. With regard to the design of the screen, it is only essential that the secondary display symbol obscures or obscures the primary index symbol 22 with the exception of the states explained below. For reasons to be explained below, a significant essential feature of the medium forming the primary display symbol 22 is that it differs from those of the screen 23 in its reflective and light-weakening properties when itcides are uniformly illuminated. This is best achieved by making the primary display symbol a lower average density that is darker than that of the background pattern. For example, a partially light-weakening symbol embodied in a continuous blackening tone, as described in more detail in the first additional patent 1,273,854, is suitable for this purpose. However, it is even more advantageous to produce the primary index symbol in the ^{manner described in the supplementary patent application P 12 (} ) 9 904.1: In this case, the index symbol 22 is not represented by continuous areas which partially absorb incident light, but rather by discontinuous areas which essentially contain all of the incident light absorb, defined such that light incident on the spaces between the regions is transmitted unattenuated.

Thus, in the areas that cover the spaces between the screen, the primary display symbol a given fraction of the background light is allowed to pass through to the viewer. In those areas of the symbol, which cover the screen itself, becomes the same fraction of light in the direction reflected on the viewer, with the result that all areas of the primary display symbol appear equally light or equally dark in the photometric balance state. An advantageous way to Production of such a photometer target consists in that the primary display symbol 22 through a suitably fine-patterned grid

ίο on one on one side of a translucent Carrier-attached coating of a photosensitive emulsion photographicrt. The subsequent Development results in a slide with a finely dabbed pattern on it that contains a multitude of essentially totally absorbent having separate areas which are the primary index symbol

22 define. It should be emphasized that a speckle pattern in which the speckles are inside the envelope of a primary index symbol, in each direction

ao looks equivalent to an arrangement in which the dots are outside the envelope of the index symbol lie.

After a slide has been produced in this way, the next step is preferably the reflective screen containing the secondary display symbol in an opaque white Ink or color applied directly to the emulsion side of the slide, in a conventional way Printing or screen printing processes. The target obtained in this way can have a configuration have, as shown, for example, in the enlarged elementary representations of FIGS. 2 and 3 is reproduced: the primary index symbol 22 is thereby represented by a fine pattern of opaque black polka dots 26 formed, which in diagonally are arranged at an angle of about 45 to the horizontal with rows in between transparent areas. These black spots are contained in the emulsion, which is

Ao is located directly on one surface of a permeable film carrier 24. The patterned white screen

23 with its related secondary index symbol 27 is applied directly to the emulsion on the side opposite the viewer.

I'm avoiding being totally absorbent Dots as a result of the illumination by the lamp 12, which is arranged obliquely with respect to the optical axis or line of sight, a shadow on the Throw white reflective patterns, the thickness of the layer should be kept as small as possible. Such a shadowing would change the appearance of the primary display synibole in that area where it lies in Cberdeckunc with the reflective screen, distort. Accordingly, the layer from the photosensitive emulsion must be as thin as possible: the thickness shown in Fig. 3 is for reasons in order to more clearly illustrate the invention.

The comparison target 17 thus has a primary display symbol 22 in the form of a weak central one Tint in direct coverage over a secondary index symbol 27. that forms an integral part of the discontinuous reflective screen 23. The primary and the secondary index symbols are in the embodiment shown by the words -YES 'and ΛΌ «reproduced: the designation should be independent »Index or display files \ mbol ·. · All possible

other complementary letters or groups of letters or any meaningful display symbols.

The following three photometric relationship states are possible between the light sources 11 and 12: the Screen 23 less bright than the background; the screen 23 has the same brightness as the background; the screen 23 lighter than the background. In the Fi g. 4, 5 or 6 the views are shown as they are to a viewer in each of the three states mentioned perform. It should be emphasized that the primary display symbol 22 is only shown in FIG. 5 is clearly perceptible, since the entire background against which the symbol is seen is uniformly bright, while in the F i g. 4 and 6 the primary index symbol is slightly visible, but due to the predominance of the secondary index symbol on the background in front of which the primary index symbol exists, obscured and unrecognizable in its meaning is made.

As shown in FIG. 4, the screen 23 appears dark against a light background when that light coming from the diffuser 16 and passing through the interstices of the screen is brighter than the light from the light source 12 reflected by the screen. In this case, appears for the The secondary display “NO” is visible to the observer, and the primary display symbol 22 is basically weakly visible, but its meaning cannot be perceived.

When the light coming from the scene light source 11 is weakened by the diaphragm device 14 so much that that from the diffuser 16 through The light passing through the spaces between the screen is less bright than the light from the comparison light source 12 reflected by the screen, the screen appears bright against a dark background. And again, as shown in FIG. 6th is shown, the indication "NO", and the primary display symbol is obscured. It should be emphasized, however, that the appearance of the individual areas that form the screen and its background, compared to FIG. 4 is reversed. Those areas that in Fig. 4 were bright are shown in FIG. 6 dark, and vice versa.

At a certain mean setting of the diaphragm 14, the brightness of the light passing through the spaces of the reflective screen becomes equal to the sacredness of the light reflected from the screen pattern; in this state, d. H. in the photometric balance state, the salient characteristics of the screen structure disappear the observation, since the entire field of view now appears uniformly and uniformly illuminated, with the exception of the primary display symbol »YES«, which can now be perceived alone and clearly, as in Fig. 5 shown. The primary index symbol appears less bright than the background, and as a result of the attenuation of the light coming from the background by the primary index symbol. Since the eye responds well to smaller changes in brightness between adjacent areas, even a slight photometric detuning will cause the patterned screen and the secondary display symbol on which the primary index symbol is superimposed become visible to the viewer. The designation »clearly evident perceptible «thus refers to a situation.

in which the primary display symbol is visible against a uniformly lit background, d. H. to a situation in which no overlapping pattern or secondary index symbol is perceivable. is cash.

That position of the diaphragm device 14 in which the opening 19 is just large enough that the The index symbol is clearly perceptible and has a functional relationship with the average borrowed or medium brightness of scene 11 if the brightness of the lamp 12 is kept constant. The position of the diaphragm device can thus be used Display of the average or mean scene brightness can be calibrated in such a way that the described Device according to the invention can serve as a light meter. Alternatively, the device can be built directly into a camera, when the position of the diaphragm to form the exposure value of the shutter device of the camera

ao is used.

Claims (5)

Patent claims: 1. Comparative photometer according to claim 4 of additional patent 1273 854 to patent 1260179, as in which the brightness of two light sources in can be compared to a common field of view that is displayed on a translucent support in Overlap with a predefined, low-contrast primary index symbol ("YES") discontinuous one having a plurality of permeable spaces, a secondary symbol ("NO") containing pattern made of a light-reflecting material, the carrier of facing away from the viewing device Side with light from one light source translucent and illuminated from the viewing side with light from the other light source and devices for changing the relative brightnesses of the two light sources are provided are in such a way that the primary symbol appears at a given ratio of the brightnesses of the two light sources (adjustment) in the field of view a uniformly bright background is clearly noticeable, while all of the given ratio of the brightness deviating states together with the das Primary index symbol imperceptible patterning the secondary index symbol is perceptible, characterized in that the primary index symbol ("YES", 22 in FIG. 1, 26 in FIGS. 2 and 3, 25 in FIG. 5) and the secondary index symbol ("NO", 27) are arranged overlapping each other and that the secondary index symbol (27) superimposed primary Index symbol (22, 26, 25) is carried out in a low mean blackening tone. 2. Comparison photometer according to claim 1, characterized in that the secondary Index symbol (27) of reflective pattern (23) superimposed primary index symbol (22, 26, 25) consists of a medium that has a reflectivity of the reflective pattern (23, 27) has different reflectivities. 3. comparative photometer according to claim 1 or 2, characterized in that the primary index symbol (22) consists of a plurality of areas (26 in Fig. 2 and 3), which absorb essentially all incident light, as well as from a CC? 632 8Ξ There is a multitude of areas which essentially transmit all of the incident light. 4. Comparative photometer according to one or more of the preceding claims, characterized characterized in that the translucent carrier (24 in Fig. 3) on its from the viewer (18, 21 in Fig. 1) facing away from a thin side containing the primary index symbol (26 in Fig. 3) Layer is provided on which the secondary index symbol (27 in FIG. 2, 3, 4 and 6) containing discontinuous patterns (23) is applied. 5. A method for producing the target for the photometer according to claim 4, characterized in that that you have a translucent carrier (24 in Fig. 3) on one side with coated with a thin photographic layer and in this by photographic exposure and development produces the primary index symbol in a low to medium density and then the developed photographic layer containing the secondary symbol is applied printed discontinuous pattern (23) made of a reflective material. 1 sheet of drawings