WO2020259863A1

WO2020259863A1 - Device for optimising the illumination variants of an illumination unit for appliances

Info

Publication number: WO2020259863A1
Application number: PCT/EP2019/086167
Authority: WO
Inventors: Jörg Reinhardt; Dietrich Martin
Original assignee: Carl Zeiss Meditec Ag
Priority date: 2018-12-20
Filing date: 2019-12-19
Publication date: 2020-12-30
Also published as: DE102019209320A1

Abstract

The invention relates to a device with which the different illumination variants of an illumination unit, in particular for ophthalmological appliances, can be optimised in terms of their light output power or another parameter. The proposed device consists of an illumination source, a filter-changing unit having different spectral filters and/or a screen-changing unit having screens of different apertures for generating different illumination variants with defined spectral and/or geometric illumination distributions. According to the invention, in addition to the spectral filters and/or screens present in the filter- and/or screen-changing unit, there is at least one additional filter for the targeted attenuation of the illumination distribution of an illumination variant. The proposed illumination unit is intended for ophthalmological appliances, in particular for examination and documentation, such as fundus cameras, surgical microscopes and slit lamps. However, the solution can also be applied wherever illumination variants with an approximately identical or application-specific light intensity are to be generated using an illumination source and different filters and/or screens.

Description

Device for optimizing the lighting variants of a lighting unit for devices

The present invention relates to a device with which the different lighting variants of a lighting unit for devices, in particular for ophthalmic devices, with regard to their light output power or other parameters such. B. a "same" brightness impression or the maximum allowable illuminance can be optimized.

The basic idea for the different applications is to optimize different lighting parameters of different lighting variants of a lighting unit by deliberately weakening “stronger” lighting variants. The parameters to be optimized in the spectrally selective case (different colors) can be, for example, an identical brightness impression or identical light output powers despite different colors. In the geometrically selective case (different apertures) this can be, for example, the time until reaching a e.g. normative limit value of a lighting dose. This is made possible by the introduction of new, significantly more efficient light sources and the associated lower thermal power loss that has to be managed.

Devices are sufficiently known from the prior art that have several color and / or geometric lighting variants. This also applies to ophthalmic devices, especially for examination and documentation on the eye, such as fundus cameras and slit lamps.

In addition to the classic white lighting, these devices usually also contain settings for other lighting, e.g. B. for a blue Be lighting for fluorescence excitation, and a red-free lighting for contrast enhancement in the representation of blood vessels. Sometimes gray or cold glass filters are also available to quickly and specifically target the Reduce brightness by a predetermined amount or suppress a portion of near-infrared light that is not required for diagnosis. Such devices rarely also include red lighting for the examination area.

In addition, it is often possible for the devices to provide different geometric apertures for shaping the illumination field. This can e.g. in the fundus cameras a setting for lighting with small pupils or with a slit lamp column differently fixed width or ring or rectangular diaphragms with ver different geometric dimensions.

It is possible for the user to have different, spectrally optimized lighting variants, e.g. the anterior segment of the eye (transparent media) and the posterior segment of the eye (through bleeding tissue).

The same (multi-spectral / broadband) lighting source is almost always used for the different colored lighting. The different colors are then selected by pivoting various filters into the illuminating beam path, which suppresses the undesired spectral light components. This inevitably means that the light distributions appear differently bright because one or more spectral areas are suppressed.

Incandescent and halogen lamps, for example, are used as the lighting source, which generate the light through the glow emission of an electrically heated filament (thermal radiators). However, the energy efficiency of these thermal emitters with a visible useful light component of only approx. 5% energy conversion is very low, so that only a light yield in the range of 10 to 30 Im / W can be achieved. The largest proportion of The energy used is emitted to the environment in the form of long-wave and therefore invisible thermal radiation.

For example, reference is made to DE 103 14 944 A1, which describes an arc lamp-based lighting and irradiation unit for ophthalmic devices. Optical filters, diaphragms and / o optoelectronic light modulators are used to generate special lighting patterns and / or profiles.

In addition to the poor energy efficiency mentioned, the use of such thermal emitters as a source of illumination has the disadvantage that the heat radiation from the device must be dissipated in a targeted manner to the environment without creating a burden / hazard for the operator or patient.

With such lighting sources, this fact leads to increased costs for installation space and heat protection measures in addition to a reduced, achievable maximum illuminance. Maximum permissible light intensities are dependent on the light distribution for the use of medical diagnostic devices on the eye z. B. in ISO 15004-2: 2007 (Ophthalmic instruments - Basic requirements and test methods - Part 2: Protection against exposure to light).

For ophthalmic devices with only one source of illumination, the "neutral", white illumination generates the highest radiation exposure of the eye. All other light distributions are usually based on this maximum possible light intensity and are therefore usually significantly reduced. This leads to the The maximum available intensity, e.g. for fluorescence excitation, is relatively low, since large spectral ranges of the spectrum emitted by the illumination source are suppressed by filters. Recently, however, other lighting sources, such as LEDs, have prevailed, which use quantum processes to generate light and achieve a significantly greater light output of 60 to 160 Im / W. In addition, the proportion of useful light is significantly increased by approx. 30%. In this way, the electrical power to be made available for the same luminous flux can be reduced by approx. 80-85%. Since a smaller part of the electrical power is converted into heat, the light sources do not reach temperatures that are nearly as high and the resulting waste heat is much easier to control.

For this purpose, reference is made to DE 10 2006 010 105 A1, which describes an ophthalmic device with homogeneous illumination. In this case, spectrally selectively emitting radiation sources on an organic or inorganic basis, such as, for example, LEDs, SLDs, lasers or OLEDs, are used as the illumination source. Different colors for the lighting can be generated here by targeted control of individual or several radiation sources, whereby these can emit broadband, narrowband or even monochromatic spectra. With this solution, too, it is necessary to keep the radiation exposure of the eye as low as possible and within the permissible limits. For this purpose, the optical power and / or the geometry of the light emitted by the individual radiation sources must be determined, monitored and, if necessary, corrected.

Ophthalmological devices are also known from the prior art, the lighting unit of which includes means for changing or adapting the amount of lighting light to different situations. This takes place in that the filter / diaphragm type selected from a plurality of filter types and / or diaphragm types with different optical properties and pivoted into the optical path of the lighting system is detected and the illumination light source is controlled in this way is that the amount of illuminating light is automatically adjustable to an amount that corresponds to the detected filter / diaphragm type. As a result, the different colored illuminations should have the "same" brightness impression or the normatively maximum permissible illuminance should be complied with.

It should be noted, however, that the constant change in the amount of illumination light can lead to a problem with necessary safety analyzes with regard to the maximum radiation exposure of the eye. Proof of a function that is error-free and therefore harmless under all circumstances is only possible with increased effort and possibly not at all.

The present invention is based on the object of developing a lighting unit for ophthalmic devices that eliminates the disadvantages of the known solutions, so that different lighting variants with regard to their light output power are at least approximately the same or optimized for their specific application. Furthermore, compliance with the provisions regarding the maximum permissible radiation exposure of the eye should be guaranteed under all conditions.

This object is achieved according to the invention with the device for optimizing the lighting variants of a lighting unit for devices, consisting of a lighting source and a filter exchange unit with different spectral filters and / or a diaphragm interchangeable unit with diaphragms of different aperture for generating different lighting variants with defined spectral and / or geometric lighting distributions, characterized in that in addition to the spectral filters and / or diaphragms present in the filter and / or diaphragm interchangeable unit, there is at least one additional filter for targeted attenuation of the lighting distribution of one of the lighting variants. According to the invention the object is achieved by the features of the independent claims. Preferred further developments and refinements are the subject of the dependent claims.

According to a first preferred embodiment, there is at least one additional filter for targeted attenuation of the most energetic lighting variant of an ophthalmic device.

According to a second preferred embodiment, there are several additional filters for attenuating the higher-energy lighting variants, which are designed as gray filters and have no or only a slight influence on the spectral (s) and / or geometric (s) property (s) of the respective gen spectral filter (s) / apertures. The (weakened) spectral characteristic is essential here. The filters for attenuation can be made of glass, plastic, gel or other materials.

Another advantageous embodiment relates to the arrangement of the additional filters for attenuation, these can for example:

• be integrated in another exchange unit,

• be assigned to the respective spectral filter and / or the respective diaphragm and integrated into the respective filter and / or diaphragm exchange unit or

• be applied in the form of a (thin) reflector or absorber layer to the respective spectral filter or the corresponding aperture.

According to the invention, the additionally present filters for attenuation are dimensioned in such a way that all lighting variants are approximately the same with regard to their light output power or another parameter, such as, for example, a “same” brightness impression. The proposed lighting unit is intended for ophthalmic devices, in particular for examination and documentation, such as fundus cameras, surgical microscopes and slit lamps. However, the solution can also be used wherever a lighting source and different filters and / or diaphragms are to be used to generate lighting variants with approximately the same or application-specific light intensity.

The invention is described in more detail below using exemplary embodiments. To show

Figure 1: the relative energy emitted by a lighting source for lighting variants generated by means of spectral filters,

Figure 2: the relative energy emitted by a lighting source for lighting variants produced by means of spectral filters and a filter for attenuation,

Figure 3: the relative energy emitted by a lighting source for lighting variants generated by means of spectral filters and filters for attenuation,

FIG. 4: the relative energy emitted by a lighting source for lighting variants generated by means of different apertures,

FIG. 5: the relative energy emitted by a lighting source for the energy distribution generated by means of two different diaphragms and a filter for attenuating the higher-energy lighting variant, and FIG FIG. 6: the relative energy emitted by an illumination source for illumination variants produced by means of various diaphragms and filters for attenuation and their exemplary dimensioning.

The proposed device for optimizing the lighting variants of a lighting unit for devices consists of a lighting source, a filter changing unit with different spectral filters and / or a diaphragm changing unit with diaphragms of different apertures for generating different lighting variants with defined spectral and / or geometric Lighting distributions.

According to the invention, in addition to the spectral filters and / or diaphragms present in the filter and / or diaphragm interchangeable unit, at least one additional filter for the targeted attenuation of the lighting distribution of a lighting variant is available.

A detailed description of the method according to the invention for optimizing lighting variants is given below by way of example. A comparable description of the use of diaphragms with different apertures is given below.

According to a first advantageous embodiment, there is at least one additional filter for the targeted attenuation of the most energetic lighting variant of an ophthalmic device.

In addition, FIG. 1 shows the relative energy emitted by an illumination source for illumination variants generated by means of spectral filters. While the lighting variant "White 1" corresponds to the spectrum of the lighting source, the lighting variants "White 2", "Green", "Red" and "Blue" result from the lighting source with the help of different spectral filters. Since the lighting variant "White 1" corresponds to the spectrum of the lighting source (without an additional filter), its energy content is clearly the highest. It should be noted that the energy content of the respective lighting variant turns out to be smaller, the narrower the corresponding spectral filter is. Due to the different filter characteristics and the spectrally dependent energy content, there are significantly different, but increasingly smaller, energy emissions in the individual lighting variants.

The invention is based on the idea of specifically weakening the high-energy spectral lighting variants, which thus also define the maximum radiation exposure for the eye.

Raising the radiation output of the lighting source while adhering to the limit value for the maximum radiation exposure after weakening the high-energy lighting variants then inevitably means that the output of the light source and thus all other lighting variants can be increased and thus optimized or increased for the respective application .

According to the invention, in addition to the existing spectral filters in the filter change unit, at least one additional attenuating element, for. B. a neutral filter to attenuate the most energetic lighting variant IN ANY.

For this purpose, FIG. 2 shows the relative energy emitted by an illumination source for illumination variants generated by means of spectral filters and a filter for attenuation.

In contrast to the illustration shown in Figure 1, the lighting variant "White 1" (spectrum of the lighting source) has an additional ches filter to weaken it. For example, the filter is dimensioned so that the energy content of the “White 1” lighting variant is identical to that of the “White 2” lighting variant. In this specific example, the optical density of the filter has a value of OD = 0.32. In addition to optimizing the energy content, it is also possible to adjust the visual brightness impression.

The attenuation of the most energetic lighting variant "White 1" is generally compensated by increasing the radiation power of the lighting source in the specific example by a factor of 2.1.

After this increase, the energy of the “White 1” lighting variant is identical to the entrance situation shown in Figure 1 (without filter, without increased radiation power). It can be seen, however, that the energies of all other lighting variants were also increased by a factor of 2.1.

However, there are preferably several additional filters for attenuating the high-energy lighting variants and particularly preferably for all except the low-energy lighting variant.

In accordance with the idea according to the invention, it is also possible to have all lighting variants shine with at least approximately the same energy. For this it is necessary to sensibly weaken all but the lowest-energy lighting variant with additional filters and to increase the radiation output of the lighting source used by a corresponding value, taking into account the limit value for the maximum radiation exposure to the eye.

In addition, FIG. 3 shows the relative energy emitted by an illumination source for the attenuation generated by means of spectral filters and filters. lighting variants, whereby only the least energy-efficient lighting variant has no attenuating filter. It should be noted that the lighting variant with the lowest energy consumption (in our example lighting variant "red") defines the overall brightness and all other lighting variants are to be supplemented with appropriately dimensioned filters and thus appropriately weakened. The absolute radiation output of the lighting source must then be increased accordingly.

Just for the sake of completeness, it is mentioned here that you can also add an additional filter to the weakest lighting variant, even if this does not necessarily make sense technically.

As a result, FIG. 3 shows that it is possible for all lighting variants to emit at least approximately the same energy. The lighting variant with the weakest energy is not further weakened according to the invention. All other lighting variants are correspondingly attenuated in accordance with their stronger transmission compared to the least energy-efficient lighting variant.

In contrast to FIGS. 1 and 2, FIG. 3 contains an additional scale on the right-hand side which describes the optical densities OD of the filters for attenuation. The corresponding values are shown in the diagram as bars. In order to achieve the original radiation energy (Figure 1) for the “White 1” lighting variant, the radiation output of the lighting source must be increased by a factor of 4.5 in this example. The correspondingly larger waste heat must be discharged in a controlled manner.

According to the invention, the additionally present filters for attenuation are designed in such a way that they do not influence the spectral properties of the respective spectral filters. Both different functionalities (spectral characteristics and transmission) can, however, also be integrated in one optical component. The additional filters for attenuation can be designed in different ways and integrated into the device for optimizing the lighting variants of a lighting unit for ophthalmological devices.

It is thus possible to assign the additional filters to another filter change unit or to the respective spectral filter and to integrate them into the filter change unit.

If the additional filters are integrated into a further filter change unit, this can for example be arranged in the optical beam path collinear with the filter change unit with the spectral filters.

According to an advantageous embodiment, the additional IN ANY those filters for attenuation in the form of z. B. thin reflector / absorber layers can be applied to the respective spectral filter.

For the dimensioning of the additional filters, it is crucial whether they are used only to allow all lighting variants to emit approximately the same energy, or whether the lighting variants can be optimized for their respective application with the aid of the filters. To do this, the input intensity of the lighting source and the dependency of the energy distributions of the individual lighting variants must be known.

According to the invention, the attenuating filters are designed as gray filters and consist of glass, plastic, gel or other materials.

Although only exemplary embodiments have been described for attenuating one or all but the lowest-energy lighting variant, it is of course possible to attenuate any number of lighting variants using filters. So it is not necessary to have all of the existing ones Manage lighting variants. Rather, only two or more can be optimized and the remaining ones used according to their existing luminosity.

The light distribution to be achieved can be optimized in particular according to the energy, the perception of brightness, the V () curve or some other useful variable.

According to a further advantageous embodiment, there is at least one additional filter for the targeted attenuation of the most energetic lighting variant with the largest lighting aperture or diaphragm of an ophthalmic device.

For this purpose, FIG. 4 shows the relative energy emitted by an ideally homogeneous lighting source for lighting variants generated by means of different diaphragms. As an example, diaphragms with circular apertures each with half the diameter are assumed. As the aperture decreases, the relative energy emitted also decreases.

Here, too, the invention is based on the idea of deliberately weakening the energy-rich lighting variants with larger apertures, which thus also define the maximum radiation load for the eye.

Raising the radiation output of the lighting source while maintaining the limit value for the maximum radiation exposure after weakening the high-energy lighting variants inevitably means that the output of the light source and thus all other lighting variants can be increased and thus optimized or increased for the respective application is. According to the invention, there is at least one additional attenuating element, for example a neutral density filter to attenuate the most energetic lighting variant (with the largest aperture).

For this purpose, FIG. 5 shows the relative energy emitted by an illumination source for the illumination variant generated by means of a diaphragm 1 and a filter for attenuation.

In contrast to the illustration shown in Figure 4, the lighting variant with aperture 1 (maximum circular aperture, e.g. d = 16 mm) has an additional filter to weaken it. The filter is dimensioned so that the energy content of the lighting variant with diaphragm 1 is identical to the lighting variant with diaphragm 2 (circular aperture, d = 8 mm).

In this specific example, the diameters of the apertures are halved. The optical density of the additional filter for the lighting variant with aperture 1 thus results in a value of OD = 0.6.

The attenuation of the most energetic lighting variant with aperture 1 is basically compensated for by increasing the radiation power of the lighting source in the specific example by a factor of 4.

After this increase, the time to reach e.g. normative limit value of the lighting variant with aperture 1 identical to the input situation shown in Figure 4 (without filter, without increased radiation power). It can also be seen that the times of all other lighting variants have also been increased by a factor of 4.

However, there are preferably several additional filters for attenuating the more energetic lighting variant, and particularly preferably for all but the least energy-efficient lighting variant. According to the inventive concept, it is also possible to weaken all lighting variants so that the time until a normative limit value is reached is almost identical. For this it is necessary to sensibly weaken all but the lowest energy lighting variant (smallest aperture) with additional filters and to increase the radiation power of the lighting source used by a corresponding value, taking into account the limit value.

For this purpose, FIG. 6 shows the relative energy emitted by a lighting source for lighting variants generated by means of various diaphragms and filters for attenuation, with only the lighting variant with the lowest energy having no attenuating filter. It should be noted that the lighting variant with the lowest energy consumption (in our example:

Aperture d = 1 mm) defines the overall brightness and all other lighting variants have to be supplemented with appropriately dimensioned filters and thus attenuated appropriately. The absolute radiation output of the lighting source must then be increased accordingly. For the sake of completeness, it is mentioned here that you can also provide the lowest-energy lighting variant with an additional filter, even if this does not necessarily appear to be technically sensible.

As a result, FIG. 6 shows that it is possible for all lighting variants with diaphragms to emit at least approximately the same dose. The lighting variant with the weakest energy is not further weakened according to the invention. All other lighting variants are attenuated in accordance with their stronger transmission compared to the least energy-efficient lighting variant.

In contrast to FIGS. 4 and 5, FIG. 6 contains an additional scale on the right-hand side which describes the optical densities OD of the filters for attenuation. The corresponding values are in the diagram as Bar shown. In order to achieve the original radiation energy (FIG. 4) for the lighting variant with aperture 1, the radiation power of the lighting source must be increased by a factor of 256 in this example. The correspondingly larger waste heat must be discharged in a controlled manner.

According to the invention, the additionally present filters for attenuation are designed in such a way that they do not influence the spectral properties of the respective lighting variants. Both different functionalities (spectral characteristics and transmission) can, however, also be integrated in one optical component.

The additional filters for attenuation can be designed in different ways and integrated into the device for optimizing the lighting variants of a lighting unit for ophthalmological devices.

The preferred embodiment of the invention is a direct (mechanical) assignment of the attenuating filter to the corresponding diaphragms of the lighting variants.

The options for filter positioning / assignment given above apply accordingly.

The o.a. Statements on how to optimize the application of the filters apply here accordingly.

Although only exemplary embodiments have been described for attenuating one or all but the lowest-energy lighting variant, it is of course possible to attenuate any number of lighting variants using filters. It is therefore not necessary to manage all existing lighting variants. Rather, only two or more can be optimized and the remaining ones used according to their existing luminosity. It should also be noted that the apertures do not necessarily have to be circular, but can also be rectangular or shaped differently. The area that is released for light to pass through is decisive. It is thus also possible to include ring-shaped apertures (circular aperture with an inner intranspa pension area) in this consideration.

Apertures with variable transmission (e.g. 100% in the middle and then with a distance from the middle, e.g. linear or bell-shaped decreasing transmission) can be included in this consideration.

Finally, reference is made to other possible variants in the selection, dimensioning and arrangement of the filters, which:

• are not necessarily neutral filters,

• are not necessarily volume absorbers,

• can be designed as a dielectric thin layer,

• can be designed as an absorber or reflector layer,

• are not necessarily used transmissively,

• can also have a reflective effect,

• also combinations of the above Can be variants

• can be provided with an anti-reflective layer and

• do not necessarily have to be applied to plane-parallel supports.

With the solution according to the invention, a lighting unit for ophthalmic devices is made available, with which existing lighting variants can be optimized with regard to their light output power or an "equal" brightness impression.

With the proposed solution it is also possible to adjust the light output power of the different lighting variants for their specific application optimize while ensuring compliance with the provisions regarding the maximum permissible radiation exposure of the eye under all conditions.

The invention represents an exclusively hardware-based solution for a lighting unit, which thus offers considerable cost and simplification advantages over known software or sensor-based solutions. This massively reduces the potential risk of failure / failure, which is also reflected in the manufacturing and development costs.

The higher thermal load resulting from the increase in the radiation output of the lighting source can be compensated for by choosing a suitable lighting source.

Compliance with the limit values for the maximum radiation exposure for the eye is determined when dimensioning the neutral density filter for attenuation and no longer needs to be measured or checked during operation.

This control of the lighting unit is thus much easier and cheaper to implement than with the known variants described above.

Claims

1. Device for optimizing the lighting variants of a lighting unit for devices, consisting of a lighting source and a filter exchange unit with different spectral filters and / or a diaphragm interchangeable unit with diaphragms of different apertures for generating different lighting variants with defined spectral and / or geometric lighting distributions, characterized in that, in addition to the spectral filters and / or diaphragms present in the filter and / or diaphragm interchangeable unit, at least one additional filter is provided for the targeted attenuation of the lighting distribution of a lighting variant.

2. Device according to claim 1, characterized in that the device for optimizing the lighting variants of a lighting unit is for ophthalmic devices.

3. Device according to claims 1 and 2, characterized in that several additional filters for attenuating the energetic Be lighting distributions of lighting variants are available.

4. Device according to claims 1 and 2, characterized in that additional filters are available for all but the lowest energy lighting distribution of a lighting variant.

5. Device according to claims 1 to 4, characterized in that the additional filter (s) for targeted attenuation does not affect the spectral (s) and / or geometric (s) property (s) of the respective spectral filter (s) (s) / have apertures.

6. Device according to claims 1 to 4, characterized in that the / the additional existing filter (s) are integrated in a further / additional exchange unit.

7. Device according to claims 1 to 4, characterized in that the filter (s) additionally present is / are assigned to the respective spectral filter and / o the respective aperture and is / are integrated into the respective filter and / or aperture exchange unit .

8. Device according to claims 1 to 4, characterized in that the additionally present filters are applied to the respective spectral filter in the form of a thin reflector / absorber layer.

9. Device according to claims 1 to 4, characterized in that the additionally present filters are dimensioned so that almost the same energy is emitted in all lighting variants.

10. Device according to claims 1 and 4, characterized in that the additional filters are dimensioned so that an energy optimized for their respective application is emitted in all lighting variants.

11. Device according to claims 1 to 4, characterized in that the additionally present filters are designed as gray filters.

12. Device according to claims 1 to 4, characterized in that the additional filters made of glass, plastic, gel or other materials are made.

13. Device according to claims 1 to 4, characterized in that the various spectral filters and / or diaphragms, as well as the additional Filters for attenuation are monolithically applied to a support made of glass, plastic, gel or other materials.