DE202006020998U1 - Test light source - Google Patents

Abstract

Test light source for emitting light with a certain intensity with a light source (7), with a light transmitter (3) assigned to the light source (7), into which the light source (7) radiates light, and with at least one window (15) which part of the light radiated into the light transmitter (3) emerges again, characterized in that the light transmitter (3) consists of a material that diffuses the incident light, the light transmitter (3) is rod-shaped. the light source (7) is arranged at the rear end of the rod-shaped light transmitter (3) and that the window (15) is provided at the opposite, front end of the rod-shaped light transmitter (3), the light exit surface in the window (15) of the light transmitter (3) is spherical is formed, the light transmitter (3) has a cylindrical outer surface, a rod-shaped housing (1) is provided which has a front area in which the light transmitter (3) and the light source (7) are inserted, and a rear area in which an electrical circuit (9) for ...

Description

The invention is based on a device having the features specified in the preamble of claim 1. Such a device is from the US 6,335,997 known. It has an electronically stabilized light source and a number of optical fibers or fiber optic bundles which are spaced apart. The optical fibers are irradiated with light from the stabilized light source via their lateral surfaces. Part of the light is emitted by the optical fibers or optical fiber bundles again via their lateral surface. The end portions of the optical fibers or fiber optic bundles stuck covered in tunnels. From one end, a tubular casing, which consists of opaque material, is pushed onto the optical fibers or onto the optical fiber bundle. The different optical fibers or fiber optic bundles wear hose sleeves of different lengths. The optical fibers or fiber optic bundles absorb different amounts of light, and indeed the less, the shorter their length is from the tubular casing. Above the end portion, which is not covered by a tubular casing, the tunnels each have a window through which light which exits through the lateral surface of the optical fiber passes through and can be observed.

By adjusting the length of the tube sections, it is possible to form surface light sources with different intensities.

Such light sources are needed to verify the temporal stability of photometers, especially those used to determine the intensity of the light emitting samples in which chemical or biological luminescence reactions or fluorescence reactions occur. Such light sources can have extremely low light intensities. In some cases, individual photons are measured with the help of photomultipliers.

In order to be able to check the stability of light measuring devices (luminometers), test light sources are required which, on the one hand, can generate correspondingly low light intensities and, on the other hand, are stable with regard to their intensity and their spectrum over a longer period of time, if possible over several years.

The reproducibility and reliability of photometers for bioanalytics are set high standards not least due to legal regulations. The test light sources must meet the same high standards. Since the light sources in bioanalytics are usually liquid samples in cuvettes, which radiate the light isotropically over a mostly circular limited surface, it is desirable to have test light sources, the same extent as possible and as consistent as possible isotropic radiation behavior as the Show light-emitting samples.

The from the US 6,335,997 B1 known device does not meet these requirements to the desired extent and is also relatively expensive to manufacture.

Known and in the US 6,335,997 also mentioned are radioactively driven light sources. However, even if they are very weak, these are extremely expensive to handle due to legal regulations for transport as well as for import and export. Samples of a microplate format, as desired for bioanalytics, are difficult to seal in accordance with regulatory requirements because of their size and geometrical conditions.

Furthermore, test light sources are known which have a plurality of individually controlled light-emitting diodes (LEDs), which are arranged in bores of a plate and radiate directly vertically upwards. These test light sources do not radiate isotropically. In addition, it is extremely difficult to stabilize the light intensity of LEDs at the desired low intensities. Furthermore, LEDs have the disadvantage that their optical geometry and their radiation behavior is very different from that of a liquid sample of bioanalytics.

The present invention has for its object to provide a device which is suitable as a test light source for light measuring devices, which are to be used to determine the light intensity of samples in which run chemical or biological luminescence and fluorescence reactions. The device should not have the aforementioned disadvantages and in particular show a radiation behavior that comes as close as possible to the radiation behavior of liquid luminescent or fluorescent samples. In addition, the device should be inexpensive to manufacture and easy to handle.

This object is achieved by a device having the features specified in claim 1. Advantageous developments of the invention are the subject of the dependent claims.

The device according to the invention has a stabilized light source, a light transmitter associated with the light source, in which the stabilized light source emits light and at least one window through which a part of the incident light exits again. The light transmitter is formed from a material which scatters the incident light. Materials that scatter irradiated light are used in the Contrary to opaque material and in contrast to transparent material called translucent or opaque.

• • Das durch das Fenster hindurchtretende Licht vermittelt das Bild einer diffusen, flächigen Lichtquelle, vergleichbar der Oberfläche einer flüssigen Probe, welche fluoresziert oder luminesziert.
• • Gestalt und Größe des Fensters können der Gestalt und Größe typischer fluoreszierender oder lumineszierender Proben angepasst sein.
• • Das aus dem Fenster austretende Licht ist infolge der Streuung in dem Lichtübertrager weitgehend isotrop. Auch diese Eigenschaft entspricht dem Verhalten einer lumineszierenden oder fluoreszierenden Probe.
• • Der Lichtübertrager hat eine gewisse Dicke oder Tiefe. Die Streuung des eingestrahlten Lichtes findet überall in dem opaken Material statt. Jeder Punkt des Materials, an welchen ein Photon gestreut wird, ist scheinbar eine Quelle des Photons. Die aus dem Fenster austretenden Photonen kommen aus unterschiedlichen Tiefen des Lichtübertragers. Auch in soweit entspricht das Verhalten des opaken Lichtübertragers dem Verhalten einer Probe einer lumineszierenden oder phosphoreszierenden Flüssigkeit.
• • Der Lichtübertrager kann ein einfacher Festkörper sein, z. B. ein Milchglas oder ein milchiges Acrylglas. Die streuende Eigenschaft kann man durch Beimischung eines trübenden Stoffes erreichen, bei Milchglas z. B. durch Beimischen von phosphorsaurem Kalk, von Fluoriden, von Zinnoxid, Titandioxid oder von Kryolith, Titandioxid ist auch Im Falle von Acrylglas eine geeignete trübende Beimischung. Ihrer Natur nach sind Milchglas und opakes Acrylglas hinreichend beständig und in ihren Eigenschaften langzeitstabil, preiswert und pflegeleicht. Acrylglas ist darüber hinaus besonders leicht mechanisch zu bearbeiten und für Zwecke der Erfindung besonders gut geeignet.
• • Die Intensität der Lichtquelle kann auf unterschiedliche Weise eingestellt werden: Einerseits durch elektronische Steuerung der stabilisierten Lichtquelle und andererseits durch Blenden und durch die Entfernung des wenigstens einen Fensters von der stabilisierten Lichtquelle. Je größer die Entfernung des Fensters von der stabilisierten Lichtquelle ist, umso größer sind die Verluste durch Streuung und Absorption des Lichtes, bevor es das Fenster erreicht.

The invention has significant advantages:

• The light passing through the window conveys the image of a diffuse, flat light source, comparable to the surface of a liquid sample which fluoresces or luminesces.
• • Shape and size of the window can be adapted to the shape and size of typical fluorescent or luminescent samples.
• • The light emerging from the window is largely isotropic due to the scattering in the light transmitter. This property also corresponds to the behavior of a luminescent or fluorescent sample.
• • The light transmitter has a certain thickness or depth. The scattering of the incident light takes place everywhere in the opaque material. Every point of the material on which a photon is scattered is apparently a source of the photon. The photons leaving the window come from different depths of the light transmitter. Also in this respect, the behavior of the opaque light transmitter corresponds to the behavior of a sample of a luminescent or phosphorescent liquid.
• • The light transmitter can be a simple solid, z. As a frosted glass or a milky acrylic glass. The scattering property can be achieved by admixing a turbid substance, in frosted glass z. For example, by admixing phosphoric lime, fluorides, tin oxide, titanium dioxide or cryolite, titanium dioxide is also a suitable cloudy admixture in the case of acrylic glass. By their nature, frosted glass and opaque acrylic glass are sufficiently resistant and have long-term stability, low cost and easy care. Acrylic glass is also particularly easy to machine mechanically and particularly well suited for the purposes of the invention.
• • The intensity of the light source can be adjusted in different ways: on the one hand by electronic control of the stabilized light source and on the other hand by aperture and by removing the at least one window from the stabilized light source. The greater the distance of the window from the stabilized light source, the greater are the losses due to scattering and absorption of the light before it reaches the window.

In the simplest case, the device has only a single window. In this case, the light transmitter is preferably rod-shaped. At the rear end of the rod-shaped light transmitter, it is possible to arrange the stabilized light source and to use the light exit surface lying at the opposite front end of the rod-shaped light transmitter as a window. The light exit surface at the front end of the light transmitter can be a flat surface, but can advantageously also be a spherical surface, which promotes an isotropic intensity distribution of the exiting light and simulates the geometry of the usual sample vessels.

By choosing the length of the rod-shaped light transmitter and the density of the scattering pigments, the intensity of the exiting light can be adjusted.

Preferably, the rod-shaped light transmitter has a cylindrical outer surface. The lateral surface is preferably covered by a light-impermeable jacket, in particular by a gray or black jacket. On the one hand, it can weaken the light as desired and, on the other hand, form a sharper border for the light exit surface. In an advantageous embodiment of the invention, the jacket is part of a rod-shaped housing, which on the one hand receives the stabilized light source and the light transmitter and on the other hand - in the rear portion of the housing - receives an electronic stabilization circuit for the light source. The stabilization circuit preferably contains as a power source a battery which, when it is running low, can be easily replaced. At the rear end of the housing, a power button can be arranged with which the light source can be easily switched on and off.

As a light source is particularly suitable a light emitting diode whose color can be selected according to the purpose. Preference is given to light-emitting diodes which emit green or blue light.

In an advantageous embodiment of the invention is located between the stabilized light source and the light transmitter nor a diaphragm and / or a screen, with which not only the intensity of the light entering the light transmitter, are selectively weakened, but also can be prevented that light comes straight from the light source to the window; rather, an aperture ensures that only stray light reaches the window.

In a particularly preferred embodiment of the invention, the light transmitter is a plate which has two facing in opposite directions surfaces and an edge surface connecting them. Preferably, it is a flat, rectangular plate. At least one window is arranged on at least one of the two large areas of the panel, and the light source is associated with the panel such that the light from the light source does not render the at least one window rectilinear It can only reach paths after it has been scattered, so that diffused light leaks out of the window. The particular advantage of the plate is that several windows can be arranged on it and that they can be arranged and configured in such a way that conditions as present in bioanalytics when examining luminescent or fluorescent samples can be simulated particularly well. In bioanalytics, the samples are usually in cylindrical or conical recesses of a rectangular sample carrier plate. A typical sample carrier plate is made of plastic and contains a rectangular field of 8 × 12 wells with a diameter of about 7 mm, a so-called 96-well microplate. Also known are sample carrier plates, which have an approximately equal area as in the 96-well microplate an array of 16 × 24 wells, which only have a diameter of about 4 mm. There are also sample carrier plates with even higher or lower density of the wells. On a plate-shaped light transmitter according to the invention can now provide windows in the same size and in the same relative arrangement, as they have the wells on known sample carrier plates. In this case, unlike a sample support plate, it is even possible to provide the windows on both sides of the plate-shaped light transmitter, eg. B. 6 mm diameter windows on one side and 4 mm diameter windows on the other side. But you can also provide different sized windows on the same side of the plate-shaped light transmitter and z. B: form a field of 6 mm diameter windows and form another field of 4 mm diameter windows, with the windows in each field preferably arranged regularly, just as the wells are arranged on a sample support plate.

The windows can be advantageously formed by applying a mask to the plate-shaped light transmitter, z. B. imprinted or glued as a film in which the windows are formed by holes in the mask, while the mask itself is opaque. The mask is preferably as colored as sample support plates are usually also. Sample carrier plates usually have a white or black surface.

In bioanalytics, in addition to a sample with low light intensity or next to a blank, there is a sample with high light intensity. Intensity differences of 6 to 8 decades or even more occur in practice. There is a risk that scattered light from a strong sample will distort the result of the intensity measurement of a neighboring weak sample. This influence of a strong sample on the measurement result of a weak sample is called "crosstalk". Even such radiation conditions can be simulated with a test light source according to the invention. Different light intensities can be generated not only by different distances from the light source to different windows and by providing apertures and other obstacles, but also by providing a variable intensity light source or - preferably - several light sources are provided, the different light intensities are fixed.

For simulating the radiation conditions of fluorescent or luminescent samples, it is also advantageous to provide depressions in the light transmitter at least under some windows. The depressions may be bores. Through different deep holes different filling heights can be simulated.

It is not only possible to provide several light sources in order to achieve different intensities, but also to be able to test with different colors.

The light sources are expediently associated with the edge surface of the plate-shaped light transmitter. Preferably, they are arranged in one or more recesses of the plate. The arrangement is preferably made so that they radiate their light mainly parallel to the two large areas of the plate in this. This alone prevents the light from the light sources from reaching a window in a straight line; rather, it can only reach the window by scattering.

An electrical circuit operating and stabilizing the light sources is preferably likewise arranged in a recess of the plate. Preferably, a battery is provided for the power supply. Also, it is preferably provided in a recess of the plate, expediently together with the electrical circuit. The device then has the overall shape of a plate, which has the advantage that it can be used as conventional sample carrier plates for testing light measuring devices.

The invention is suitable for generating light intensities over a wide range of intensities, starting with very low intensities of the order of magnitude of 100 photons per second up to intensities which are 6 to 7 orders of magnitude greater. Such intensity ranges can be generated with light-emitting diodes, if they are operated not only in the steeper area of their current-intensity characteristic in which they are usually operated for lighting purposes or signaling purposes, but if they are also in the lower flat part of their characteristic curve, in which they deliver only a low intensity. In the steeper region of the characteristic, the light intensity is preferably kept constant by current stabilization by keeping the power consumption RI ² constant. In the flat part of the characteristic, in the range of low intensity, preferably the voltage applied to the LED is stabilized instead.

Particularly low intensities can be realized on individual windows by providing a groove in the plate between the windows and the light source (s) which provides greater attenuation of the light level.

To investigate the spectral sensitivity of a light meter, not only light sources with different emission spectrum can be used, but also color filters are used.

Embodiments of the invention are illustrated in the accompanying drawings in which like or corresponding parts are designated by like reference numerals.

1 shows schematically a rod-shaped test light source in longitudinal section,

2 shows a plate-shaped test light source in an oblique view and

3 shows the section AA through the in 2 illustrated test light source.

1 shows a test light source with a rod-shaped housing 1 which passes through a transverse wall 2 is divided into two compartments. In a front compartment is a rod-shaped light transmitter 3 with a crowned point 4 which over the housing 1 protrudes. At the rear end of the rod-shaped light transmitter 3 is a hole 5 provided, which extends from the rear end of the Lichtübertragers 3 towards the top 4 extends and an opaque aperture 6 and behind it a light source 7 receives, which is preferably a LED whose unillustrated leads through a hole 8th in the transverse wall 2 in the rear compartment of the housing 1 be guided, in which - only symbolically represented - the elements of an electrical circuit 9 are housed, including a battery 10 through which the circuit 9 and the light emitting diode 7 be powered. The battery 10 can be arranged interchangeable. Otherwise, the circuit may be potted. At the rear end of the case 1 , also indicated only schematically, is a push-button switch 11 provided by the operation of the light source can be turned on and off.

The light transmitter 3 is preferably made of milky acrylic glass. The front edge of the case 1 defines a window through which the light enters the top 4 and from this finally diffuse.

The 2 and 3 show a device according to the invention with a plate-shaped light transmitter 3 which has two large faces pointing in opposite directions 12 and 13 and an edge surface connecting them 14 Has. The upper surface 12 is through a mask 19 covered in which 3 is shown exaggeratedly thick. The mask 19 has windows formed as holes 15 , There are windows of different sizes. window 15 one and the same size are combined into fields in which the windows 15 in regular arrangement. Under the windows 15 can the plate 3 wells 16 to have. Such wells 16 do not have to be under all windows 15 be provided. As far as pits 16 are provided, they can be formed differently deep.

Near one of the edges of the plate 3 are in holes, which in the plate 3 are provided, a plurality of juxtaposed light sources 7 , in particular LEDs, provided by an electrical circuit 9 which is a battery 10 includes, and in a recess 17 the plate 3 is housed, operated. The light sources 7 Their light is mainly emitted parallel to the two surfaces 12 and 13 the plate 3 in this one. Therefore, the light can not go straight from the light sources 7 to one of the windows 15 pass and exit through this, but only after scattering of scattering pigments in the plate 3 are provided, for. B. titanium dioxide pigments in acrylic glass.

The window 15 farthest from the light sources 7 are removed, receive the least amount of light. This can additionally by a in the plate 3 Milled in slot 18 be reduced.

LIST OF REFERENCE NUMBERS

1

casing

2

partition

3

Optical transmitters

4

top

5

drilling

6

cover

7

light source

8th

drilling

9

circuit

10

battery

11

Push switch

12

area

13

area

14

edge surface

15

window

16

deepening

17

recess

18

slot

19

mask

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 6335997 [0001, 0007]
• US 6335997 B1 [0006]

Claims (7)

Test light source for emitting light of specific intensity with a light source ( 7 ), with one of the light source ( 7 ) associated light transmitter ( 3 ), in which the light source ( 7 ) Illuminates light, and with at least one window ( 15 ), through which a part of the in the light transmitter ( 3 ) radiated light again, characterized in that the light transmitter ( 3 ) consists of a light scattering the incident light material, the light transmitter ( 3 ) is rod-shaped. the light source ( 7 ) at the rear end of the rod-shaped light transmitter ( 3 ) and that the window ( 15 ) at the opposite, front end of the rod-shaped light transmitter ( 3 ), the light exit surface in the window ( 15 ) of the light transmitter ( 3 ) is formed spherical, the light transmitter ( 3 ) has a cylindrical outer surface, a rod-shaped housing ( 1 ) is provided, which has a front region in which the light transmitter ( 3 ) and the light source ( 7 ), and has a rear area in which an electrical circuit ( 9 ) for operating and stabilizing the light source ( 7 ) is provided to power the light source ( 7 ) and the circuit ( 9 ) a battery ( 10 is provided, the light source ( 7 ) is electronically stabilized, and the light source ( 7 ) is a light emitting diode. Test light source according to claim 1, characterized in that the lateral surface of the light transmitter ( 3 ) whose light exit surface is limited. Test light source according to one of the preceding claims, characterized in that the lateral surface of the light transmitter ( 3 ) of an opaque sheath ( 1 ) is covered. Test light source according to claim 3, characterized in that the jacket ( 1 ) is gray or black. Test light source according to one of the preceding claims, characterized in that directly at the rear end or laterally at the rear end of the housing ( 1 ) a switch ( 11 ) to turn on the light source ( 7 ) is provided, in particular a key switch. Test light source according to one of the preceding claims, characterized in that between the light source ( 7 ) and the window ( 15 ) an aperture ( 6 ) is provided. Test light source according to one of the preceding claims, characterized in that the light transmitter ( 3 ) is color neutral.

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