Illumination device and illumination method with limited maximum irradiance

Abstract

The present invention relates to a lighting device (100) and a lighting method for illuminating a surface (Ob) with a maximum overall irradiance. At least two lighting units (1, 2, 3) of the lighting device (100) each illuminate the surface (Ob) with a maximum irradiance. A control device (10) drives and controls each lighting unit (1, 2, 3) independently of the other lighting units, thereby changing the maximum irradiance of the lighting units (1, 2, 3). The lighting device (100) detects a user setting (9) related to the maximum overall irradiance. In response to the detection of the user setting, the control device (10) predicts what maximum overall irradiance the implementation of the user setting (9) will result in. If the predicted maximum overall irradiance is greater than a predetermined upper limit, the control device drives and controls at least one lighting unit (1, 2, 3) depending on the user setting. This driving control ensures that the upper limit is respected.

Description

[Technical Field]

[0001] The present invention relates to a lighting device and a lighting method. [Background technology]

[0002] Such an illumination device and such an illumination method are used, for example, to illuminate an operating table on which a patient undergoing medical treatment is placed, the illumination enabling the treating physician to perform the medical treatment and, in so doing, to have a good view of the area of ​​the patient's body to be treated.

[0003] Illumination necessarily provides radiant energy to the patient's body, which heats the patient's body, and if the illumination is too intense, it can dry out the patient's tissue and / or put the patient at risk of burns.

[0004] For lighting devices capable of illuminating operating tables, the standard IEC 60601-2-41 (currently in its 3rd edition) is valid. This standard specifies that the maximum irradiance of a lighting unit in a medical lighting device is currently 1000 W / m 2 700W / m in the future 2 This requirement applies to any distance between the lighting device and the operating table at any time, measured along the central axis of the lighting device. Summary of the Invention [Problem to be solved by the invention]

[0005] The problem on which the invention is based is to provide an illumination device and an illumination method which, with a relatively high degree of certainty, reduces the risk that an object, for example a patient, is endangered by the illumination. [Means for solving the problem]

[0006] The above-mentioned problem is solved by a lighting device having the features of claim 1 and a lighting method having the features of claim 12. Advantageous configurations of the lighting device according to the invention are also advantageous configurations of the lighting method according to the invention, insofar as they are useful, and vice versa.

[0007] We will now first define some concepts for medical lighting units that will be used hereinafter.

[0008] The lighting unit comprises at least one light source, preferably a plurality of light sources, which are mounted on a support and preferably configured as LEDs. In one implementation, during use, the position and orientation of a light source cannot be changed relative to the position and orientation of a particular other light source or each other light source of the same lighting unit. A controllable actuation drive may be associated with at least one light source, in particular a group having a plurality of light sources, which actuates the light source or group relative to the support and thus relative to the at least one light source or at least one other light source.

[0009] The or each light source typically emits a light beam having the shape of a cone. In one implementation, the tip of this cone is ideally located within the light source. It is also possible for the optical system to influence the design of the light beam. In special cases, the light beam is cylindrical. The light beams reaching the light sources of the lighting unit typically overlap. The lighting unit often has a central optical axis that coincides with the central geometric axis of the support.

[0010] A lighting unit has a spectral composition of emitted light, which results from the spectral composition of the light of the individual light sources and is hereinafter referred to as the "light spectrum" of the lighting unit, to which a color temperature is correlated.

[0011] "Illuminance" (Ev) is the luminous flux per unit area incident on a surface. The SI unit is Lux = Lumen / m 2 In a plane perpendicular to the optical axis of the lighting unit, the illuminance of the lighting unit typically reaches a maximum value at the intersection of the optical axis with this plane. Usually, this maximum illuminance value varies along the optical axis, and more specifically, as follows: starting from the lighting unit, this maximum value increases until it reaches a local maximum value, and then decreases again. The value at this local maximum value is called the "maximum illuminance in space" of the lighting unit. Usually, the maximum illuminance in space occurs on the optical axis. The region where the illuminance reaches a maximum value may be located on the illuminated surface or between the illuminated surface and the lighting unit. If the surface is transparent, this region may also be located behind the illuminated surface in the radial direction if the distance is short enough.

[0012] Typically, the maximum illuminance in a space that a lighting unit can achieve is known based on the design of the lighting unit or based on measurements performed before first use, in particular based on the illuminance of the light source and the relative positioning of the generated light beams with respect to each other. Depending on the design of the lighting unit or the measurements performed, it is further known how the maximum value of illuminance on the central optical axis depends on this distance. This functional dependence of illuminance on the distance may depend on other configurable or design-induced parameters of the lighting unit.

[0013] In many cases, a user, through user input, or automatically through a control device, can cause the actual maximum illuminance in a space to be less than the maximum achievable illuminance in the space. Hereinafter, we refer to "maximum achievable" illuminance and "maximum currently achieved" illuminance in a space. The maximum currently achieved illuminance in a space is less than the maximum achievable illuminance. While the maximum illuminance actually achieved on a surface typically depends on the position and orientation of the lighting unit relative to the surface, the maximum achievable illuminance in a space does not depend on this position or orientation.

[0014] In many cases, the user can set the maximum illuminance of the lighting unit, which can be changed during operation. In one implementation, the user can set the maximum illuminance in a space. In another implementation, the user can set the maximum illuminance at a predetermined reference distance from the lighting unit. In the case of surgical lighting, this reference distance is often 1 m. The maximum illuminance at the reference distance is less than or equal to the maximum achievable illuminance at the reference distance. In many cases, the maximum illuminance in a space for a medical lighting unit is achieved at a distance that differs from the reference distance by up to 10 cm.

[0015] When a lighting unit illuminates the surface of an object, such as an operating table or a patient on the operating table, the illuminance varies across the illuminated surface. Ideally, the illuminance achieved by the lighting unit on the illuminated surface reaches a maximum value at one point. This maximum value is referred to as the maximum illuminance that the lighting unit actually achieves on the illuminated surface. This maximum value is less than or equal to the maximum illuminance of the lighting unit in space. Typically, the maximum value occurs at the intersection of the lighting unit's central optical axis and the illuminated surface, even if the illuminated surface is curved and / or positioned at an angle to the central axis, which is the case for an illuminated patient.

[0016] In the following, reference is made to the "spacing" between the lighting unit and the illuminated surface. Unless explicitly stated otherwise, this means the distance along the central optical axis between the lighting unit and the illuminated surface, even if the smallest distance between the lighting unit and the illuminated surface occurs outside the central optical axis.

[0017] Illuminance is the most important factor affecting the brightness of an illuminated surface.

[0018] In the case of medical lighting units, "illuminance" often refers to the illuminance at a reference distance of, for example, 1 m between the lighting unit and the illuminated surface, the illuminated surface being perpendicular to the central optical axis of the lighting unit. In many cases, lighting units are ideally configured so that the maximum illuminance in space occurs on the central optical axis and at a reference distance from the lighting unit. In practice, this goal usually cannot be achieved exactly.

[0019] The brightness of a luminous and / or reflective surface that appears to an observer is measured in units of Cd / m 2 and is represented by luminance. In the case where a surface does not emit light, luminance depends on the illumination intensity on the surface and the reflective / absorptive properties of the surface.

[0020] "Irradiance" (Ee) is the output per unit area of ​​optical radiation incident on a surface. Its SI unit is W / m 2 Irradiance is also called "radiant intensity" or "radiant flux density," formerly known as "radiant flux density." The irradiance of a lighting unit at a point is proportional to the illuminance at this point, and the proportionality coefficient depends on the light spectrum of the lighting unit. Therefore, if the proportionality coefficient does not change, the maximum irradiance and maximum illuminance in space will occur within the same area.

[0021] Corresponding to illuminance, we also speak of the "maximum irradiance" that a lighting unit generates on the illuminated surface. This maximum irradiance also typically reaches its maximum value at the intersection of the lighting unit's central optical axis with the illuminated surface. The maximum value is also referred to as "peak irradiance."

[0022] Light field diameter d xis understood to be the diameter of a circle centered on the area of ​​maximum illuminance, the circle being defined so that the average illuminance at various points on the circle is equal to x% of the maximum illuminance on the surface of the circle. These points are, for example, evenly distributed over the circle. The surface of the circle is located perpendicular to the central optical axis of the lighting unit. Typical values ​​of x in the medical field are 10% to 50%. For surgical lighting, d 10 The diameter of the light field, d, is usually 13cm to 35cm. x usually depends on the spacing between the lighting unit and the surface of this circle, so the diameter of the light field d x is related to a reference distance, which is often 1 m for medical applications. In many cases, the user will need to specify the diameter d of the light field by user input. x Note: Since irradiance is proportional to illumination, the diameter d of the light field x is related to irradiance instead of illuminance, the same light field diameter d x occurs.

[0023] In the medical field, lighting units often require 2*d 50 >d 10 It is desired, and even required, by standards, for example the standard for surgical lighting IEC 60601-2-41, that this should hold. This requirement results in boundary conditions for how the light rays of the light sources of these lighting units are positioned relative to one another.

[0024] A "light field" is understood to be the area on the surface of an object illuminated by a lighting unit. Two properties of a light field are the illuminance profile and the irradiance profile. These two profiles assign an illuminance or irradiance, respectively, to each point on the illuminated surface. These two profiles differ only by a proportionality factor, which depends on the light spectrum of the lighting unit.

[0025] Typically, when the illuminated surface is a single plane, the curve on the illuminated surface where the illuminance and irradiance are x% of the maximum illuminance or maximum irradiance has the shape of an ellipse, especially a circle, centered at the point of maximum illuminance or maximum irradiance. In a three-dimensional view where the illuminated surface extends in the xy plane and each illuminance or irradiance is plotted at a point (x,y) on the z axis, the light field often has the shape of an approximately bell curve that is rotationally symmetric about the z axis.

[0026] The illuminance, irradiance, light field and light field diameter of a lighting unit may of course change over time and based on user behavior, especially if the user moves the lighting unit. Unless otherwise stated, current values ​​are intended.

[0027] When light is incident on a body, the body absorbs some of the light and reflects the rest. "Thermal energy," also called temperature energy, has units of joules. The thermal energy input to an illuminated body is the integral of the absorbed irradiance across the illuminated surface and over time, i.e., over the time the object is illuminated. An illuminated body, such as a patient on an illuminated operating table, receives thermal energy input from a lighting device illuminating the operating table, and optionally from other energy sources, such as heaters for the operating table, thermal radiators, and the ambient temperature. The body releases thermal energy to the surroundings, depending, inter alia, on its own body temperature and the ambient temperature. After a transient response period, thermal equilibrium occurs, where the thermal energy input equals the thermal energy output. The patient's body temperature often rises slightly, and this increase causes this thermal equilibrium.

[0028] On the one hand, it is desirable to provide good illumination of the area of ​​the patient's body where the medical procedure will be performed. This is achieved by high light intensity and / or irradiance. However, high irradiance also leads to high maximum irradiance. Therefore, on the other hand, in order to avoid endangering the patient, it is desirable that the maximum overall irradiance not be too large. Excessively high overall irradiance on the illuminated surface of the patient can result in burns and / or dryness.

[0029] Typically, medical surgical lighting generates a maximum input of 50 W of thermal energy. However, the concept of "thermal energy" refers to the load on the patient's body due to the illumination, averaged over space and time. However, particularly in medical applications, certain areas of the body are often strongly illuminated to ensure that the physician can perform the medical procedure. This can cause a high local load on the body due to the supplied radiant power. Therefore, the aforementioned thermal balance occurs in this area much later than the thermal balance averaged over the entire body. Furthermore, especially when the surgical light is turned on, the irradiance can change rapidly. The result: in this area or in a smaller subregion of the body, the temperature becomes significantly higher than in the rest of the body. This temperature difference often cannot be effectively and quickly compensated for by the flow of heat through the patient's own body and by the release of heat to the surroundings. This can lead to partial drying of the wound, localized increases in the temperature of certain areas of the body, and, in extreme cases, even mild burning. Therefore, according to the present invention, the thermal energy defined in the previous paragraph is not limited, or at least not only the thermal energy.

[0030] The present invention reduces the risk of patient injury from excessively high maximum total irradiance of a lighting device. Maximum total irradiance is a measure of the current radiant power that the lighting device is currently applying locally to the patient's body. This distinguishes maximum total irradiance from thermal energy, which is somewhat averaged over the patient's body and integrated over time.

[0031] The lighting device according to the present invention includes at least two lighting units, each capable of illuminating the same surface. Therefore, in many cases, the illuminated surface, and thus the object on the illuminated surface, is illuminated from multiple sides, which is often not possible with a single lighting unit. This feature reduces the shadowing effect caused by the object when it enters the area between the lighting device and the illuminated surface. Such an object could be, for example, a medical instrument or a body part of a doctor performing a treatment.

[0032] Preferably, the respective position and orientation of each lighting unit relative to the surface to be illuminated can be varied, and can be varied independently of the respective positions and orientations of any particular other lighting unit or of each other lighting unit of the lighting device. Limitations: Of course, two lighting units cannot penetrate each other, nor can one lighting unit penetrate another object.

[0033] That is, the lighting device according to the invention comprises at least two lighting units, each of which emits light and generates a light field and thus an irradiance at an illuminated surface, for example at an illuminated surface of a patient or an operating table. Of course, at a certain time, at least one lighting unit may be switched off.

[0034] The light fields of the lighting units are additively superimposed. The "total irradiance" of a lighting device should be understood to mean the irradiance that the lighting device currently achieves on the entire illuminated surface with its lighting units. The total irradiance also has a local maximum on the illuminated surface, which is called the maximum total irradiance, and can vary over time. The maximum total irradiance depends on the maximum irradiance that the lighting units of the lighting device achieve on the illuminated surface, as well as typically on the position of the light fields relative to one another on the illuminated surface, and to a lesser extent on the diameter and / or correlated color temperature of the light fields.

[0035] The lighting device according to the invention further comprises a control unit for signal processing. The control unit is able to drive and control each lighting unit, and can do so independently of a specific other lighting unit or each other lighting unit of the lighting device. The purpose and therefore effect of the control is to change, in particular to reduce, the maximum irradiance of the lighting unit being driven. Optionally, the control unit can change the diameter of the light field of the lighting unit and / or the correlated color temperature by this control.

[0036] Typically, each lighting unit includes a plurality of individual light sources, in particular LEDs. Preferably, each lighting unit includes at least two light source groups, each including at least one light source. Preferably, the control device can drive each light source group independently of a specific other light source group or groups of the lighting unit, and this driving control changes the maximum irradiance of this light source group. Alternatively, the light sources of a lighting unit may be driven only so that all light sources of a lighting unit belong to the same light source group.

[0037] Each individual light source and therefore each light source group generates a respective maximum irradiance on the surface. To change the maximum irradiance of the controlled lighting unit, the control device causes the respective maximum irradiance of at least one light source group to be changed.

[0038] To change the maximum irradiance of the light source group, the control device causes the light intensity parameter of the light source group to be assigned a different value. In one implementation, the control device causes the driving control to change the maximum irradiance that the light source group can generate in the space. In another implementation, the control device causes the driving control of the light source group to change the diameter of the light field of the light source group or the light spectrum of the light source group correlated to the color temperature. These implementations can be combined with each other.

[0039] Preferably, the lighting unit comprises at least two different light source groups that are driven independently of one another. In one configuration, the control device assigns different values ​​to the light intensity parameters of at least one light source group, while at least one further light source group remains unchanged. In another configuration, the values ​​of the light intensity parameters are similarly changed, for example by the same factor or the same absolute value.

[0040] The lighting device according to the invention is capable of detecting a user setting. This user setting is related to the maximum overall irradiance of the lighting device or the maximum irradiance of at least one lighting unit. "Related" means: caused by the user setting or at least suitable for changing the maximum overall irradiance or the maximum irradiance. The user setting may in particular be related to the irradiance to be maximally achieved in a space and, optionally, to the diameter of the light field of the lighting device or lighting unit or the correlated color temperature. The user setting can set the value of this parameter or can also include a setting for changing the current value, for example by means of a slide controller or by means of the plus and minus keys.

[0041] The control device is configured to automatically respond to detection of a user setting as follows: The control device at least approximately predicts what maximum overall irradiance the lighting device will achieve on the surface when the lighting device is operated in accordance with the user settings. Preferably, the control device makes this prediction assuming that the lighting device is operated as modified in accordance with the user settings but otherwise remains unchanged, in particular the respective spacings between each lighting unit and the illuminated surface, and that the respective maximum irradiances remain unchanged except for the user settings. Typically, the maximum overall irradiance predicted by the control device is an estimate for the maximum irradiance on the surface that would actually result from the realization of the user settings.

[0042] An upper limit for the maximum overall irradiance that the lighting device actually achieves or is allowed to achieve on a surface is set. This upper limit may be set, in particular, by a user or by a higher-level control. If this upper limit is exceeded, there is a risk that the illuminated person will be injured or otherwise harmed. In one configuration, this upper limit is set permanently and cannot be changed. In another configuration, the highest possible upper limit is set permanently, for example, based on legal settings or based on a determination by the manufacturer or user of the lighting device. By corresponding user input, the user or a higher-level control can also cause a lower upper limit to be used in practice. The control device detects the upper limit that is set permanently or by the user or higher-level control.

[0043] The control device compares the predicted maximum overall irradiance with this predetermined upper limit. If the predicted maximum overall irradiance is greater than the upper limit, the control device drives at least one lighting unit of the lighting device. This driving depends on the detected user settings. Preferably, the aim of the driving is that the user settings are realized as desired, or at least as far as possible. During the driving, the control device causes the following boundary condition to be observed: the actually achieved maximum overall irradiance of the lighting device, which is actually achieved after the driving, is less than or equal to the predetermined upper limit. Usually, the driving depends on the user settings and the predicted maximum overall irradiance. In special cases, the control device leaves the lighting device unchanged, since only partial realization of the user settings would exceed the upper limit.

[0044] That is, the control device, through the drive control, ideally causes the user setting to be realized as the user desires, so that the predetermined upper limit is not exceeded. "Ideally" means that the prediction is an estimate that may deviate from reality, and the control device preferably uses signals from sensors that may contain errors for the prediction. Ideally, the upper limit is respected, thereby reducing the risk that the illuminated patient will be injured by an excessively high maximum irradiance, or that nearby people will be overstrained, or that the object will be damaged.

[0045] The present invention eliminates the need for users to be careful not to exceed the upper limit when setting user settings, which is particularly useful for user settings that do not directly set the value or magnification of the maximum overall irradiance, but instead directly set another parameter that affects the maximum overall irradiance, such as the maximum irradiance of a lighting unit or the diameter of a light field.

[0046] The lighting device may include an input unit by means of which the user can change the maximum overall irradiance. The input unit may be configured in such a way that the user cannot increase the maximum overall irradiance beyond the upper limit. The present invention can be combined with such an arrangement. However, according to the present invention, the user can also change other parameters of the lighting device, such as the maximum irradiance of the lighting unit or the diameter of the light field or the correlated color temperature. According to the present invention, the control device also prevents the upper limit of the maximum overall irradiance from being exceeded in this case, without the need to configure the input unit accordingly and without the user having to take care to observe the upper limit.

[0047] In one configuration, the control device then calculates the maximum overall irradiance that the entire lighting device will actually achieve at the surface. This configuration will be explained in more detail below. According to the present invention, the control device additionally or alternatively predicts the maximum overall irradiance that would result from the user settings if the user settings were implemented as desired. In this way, in cases where the upper limit would be exceeded, the control device prevents the upper limit from actually being exceeded by driving at least one lighting unit accordingly. In special cases, the control device leaves the lighting device unchanged, i.e., the user settings are not implemented, because the upper limit would otherwise be exceeded. Thus, the present invention first prevents the undesired event of exceeding the upper limit. Such an event is subsequently confirmed, and then the maximum overall irradiance is reduced again. Such effects may particularly endanger patients and / or strain or tire the eyes of people around the illuminated surface.

[0048] The present invention is implemented in combination with a configuration in which the control device continuously determines the currently achieved maximum overall irradiance, for example at a fixed sampling frequency. How quickly an upper limit is exceeded depends in this configuration on the respective sampling frequencies of the control device and optional sensors, and also on the computational capacity of the control device. However, thanks to the present invention, this continuous scanning is no longer necessary. Instead, the maximum overall irradiance is predicted as needed, i.e., after detecting the user setting. In many cases, this feature saves the computational capacity and / or computation time of the control device.

[0049] The following configuration is possible: if the predicted maximum overall irradiance is greater than the upper limit, the control device may prompt an appropriate message, in particular an alarm, to be output, at least in a form that is perceptible to humans. However, according to the present invention, the control device automatically activates at least one lighting unit when the upper limit is exceeded, so there is no need to output such a message. This is particularly advantageous, since in everyday clinical situations, people are often overwhelmed by numerous messages. This reduces the risk that a user will not perceive or respond correctly to the appropriate message, resulting in a significant or prolonged exceedance of the maximum overall irradiance. The control device may activate at least one lighting unit and may additionally prompt an output of a message.

[0050] According to the invention, the control device predicts what maximum overall irradiance the lighting device will achieve on the illuminated surface if the user settings are realized as desired. According to the invention, the control device uses the detected user settings in relation to the maximum overall irradiance or maximum irradiance of at least one lighting unit. Different configurations are possible in which the control device uses additional information to predict the maximum overall irradiance. The invention can also be realized without using this additional information.

[0051] Preferably, the control device determines and uses the respective maximum irradiance of each lighting unit, which lighting unit actually achieves this maximum irradiance on the illuminated surface. Typically, the control device uses an approximation of the actual maximum irradiance.

[0052] In one implementation, a maximum achievable irradiance in the space is set for each lighting unit. Based on its structure and manufacturing, the lighting unit can achieve this irradiance at most, and this maximum value does not necessarily occur on the illuminated surface, but occurs at a reference distance of, for example, 1 m. The maximum irradiance that the lighting unit actually achieves in the space is less than the maximum achievable irradiance in the space and depends on the driving control of the lighting unit. Similarly, the maximum irradiance achieved on the surface can be less than the irradiance that can be achieved in the space at most, or at most equal to the irradiance that can be achieved in the space at most.

[0053] In one configuration, the control device uses the maximum irradiance of the lighting units actually achieved in the space as the irradiance to be maximally achieved on the surface, and determines the maximum irradiance to be achieved in the space depending on the maximally achievable irradiance and the drive control of the lighting units. This approximate maximum irradiance may be greater than the maximum illumination actually achieved on the surface, but will usually not be less.

[0054] Another configuration considers that the maximum irradiance achieved by a lighting unit on an illuminated surface depends on the spacing between the lighting unit and the surface and may therefore be smaller than the maximum irradiance achieved by the lighting unit in space. According to this configuration, the lighting device includes at least one spacing sensor. In one implementation, one spacing sensor is connected to each lighting unit, and the position and orientation of the connected spacing sensor relative to the lighting unit are immutable. The or each spacing sensor measures a measure of the spacing between itself and the illuminated surface. In many cases, this measured spacing can be used as the spacing between the lighting unit and the illuminated surface. Optionally, a lateral offset between the spacing sensor and the lighting unit's central optical axis is additionally used, and this lateral offset is set by construction and remains unchanged during operation. The control device uses the maximum irradiance achieved in space and the measured spacing to determine the maximum irradiance achieved on the surface.

[0055] Different implementations of this distance sensor are possible. In one implementation, the distance sensor emits electromagnetic radiation or sound waves onto a surface, which reflects at least a portion of the electromagnetic radiation or sound waves, some of which are incident again on the distance sensor, and the propagation time of the electromagnetic radiation or sound waves is measured. The propagation time is a measure for the distance being sought. It is also possible to measure attenuation, which in this case is a measure for the distance.

[0056] In another implementation, the lighting unit is connected to a camera pointed at the surface and including an autofocus function. The autofocus function automatically focuses the camera on the illuminated surface. A distance sensor detects at what distance the autofocus function focuses the camera. This autofocus distance is an estimate of the distance being sought. This configuration eliminates the need for a separate distance sensor. In many cases, such a camera is already provided, which allows, for example, the illuminated surface to be visually displayed on a spatially separated output unit.

[0057] In one implementation, the camera is positioned and configured so that at least one image of the camera shows all or at least some of the light fields that the lighting units generate on the surface. The control device evaluates the image and determines the size of each light field in the image. Furthermore, the control device determines, for each lighting unit, how the lighting unit generates a light field diameter d at a predetermined reference interval. x The diameter d of the light field at the reference interval is detected, for example, through a read access to the data memory. x is a parameter due to the structure, and the user can change this parameter due to the structure, but it is independent of the interval being searched. The control device compares the size of the light field in the image with the diameter of the light field at a reference interval and derives each interval from the result of the comparison. The reference interval is, of course, set for the control device.

[0058] If multiple lighting units are switched on, the image alone will show multiple light fields on the surface. In one configuration, the control device automatically determines which light field originates from which lighting unit. In many cases, the camera is fixedly connected to the lighting units. The control device detects the constant position and orientation of the camera relative to the central optical axis of the lighting unit. In one configuration, at least one lighting unit is fixedly connected to a distance sensor. The measured distance between this lighting unit and the surface, the diameter d of the light field of this lighting unit, x and the diameter of the light field in the image, in many cases, allows the control device to identify the light field originating from a lighting unit with a distance sensor.

[0059] What is possible here is that, without using a distance sensor, at least one lighting unit control device detects the diameter of the set light field at a reference distance and, by automatic validation, checks which light fields in the image can originate from this lighting unit and which light fields cannot originate from this lighting unit.

[0060] In a preferred configuration, the distance sensor scans the illuminated surface in a contactless manner and is thereby able to generate a 3D topographical profile of the illuminated surface. Such distance sensors are known under the name "time-of-flight sensors" and are described, for example, in DE 102013012231 A1 and DE 102012014716 A1. The control device uses this topographical profile to determine the maximum irradiance of the connected lighting units, the maximum overall irradiance and / or the distance between the lighting unit and the surface.

[0061] In one configuration, the control device uses the topographical profile to determine a minimum distance between the topographical profile of the illuminated surface and the lighting unit. This minimum distance may be less than the spacing along the central optical axis. The control device uses the minimum distance and the maximum irradiance in the space of the lighting unit to determine the maximum irradiance on the surface of the lighting unit. It is also possible for the control device to derive and use an average spacing from the topographical profile.

[0062] According to the configuration just described, the control device determines the maximum irradiance that the lighting unit achieves on the surface. the irradiance achieved by the lighting unit in the space, and The measured distance between the lighting unit and the illuminated surface Depends on and seeks.

[0063] Preferably, the control device uses a characteristic curve that indicates a coefficient as a function of the distance, which coefficient indicates the percentage of the maximally achievable irradiance in the space that the lighting unit can actually maximally achieve at this distance. This characteristic curve is known depending on the design of the lighting unit or is empirically determined in advance. The characteristic curve is preferably stored in a data memory to which the control device has at least temporary read access.

[0064] In one configuration, the control device predicts the maximum overall irradiance as follows: as the sum of the maximum irradiances of the lighting units, and if a user setting relates to the lighting units, the maximum irradiance to be achieved according to this user setting is used. The maximum irradiance results from the maximally achievable irradiance and the driving control of the lighting units. Preferably, lighting units that are switched off or faulty are not taken into account when summing. This configuration does not require sensor signals, and in particular does not require measured intervals, but does not lead to predictions of an excessively high maximum overall irradiance or an excessively low overall irradiance.

[0065] Each lighting unit achieves a light field on the illuminated surface. The concept of "light field" has already been defined above. In the case where the illuminated surface is perpendicular to the central optical axis of the lighting unit, an irradiance exceeding x% of the maximum irradiance occurs inside a circle, where x is for example 10%, and the center point of this circle is the intersection of the central optical axis with the surface. The diameter of this circle is the diameter d of the light field. x These circles of lighting units may be arranged concentrically, in which case the maximum overall irradiance is ideally equal to the sum of the maximum irradiances of the lighting units, whereas in the case where the centre points of the circles do not coincide, this sum is usually greater than the maximum overall irradiance.

[0066] In one configuration, the control device can determine, at least approximately, how these light fields are positioned relative to one another. The lighting units generate these light fields on the illuminated surface. The control device uses user settings, the maximum irradiance of the lighting units, and additionally the determined positioning of the light fields relative to one another to predict the maximum overall irradiance.

[0067] Various configurations are possible for the control device to determine how the light fields of the lighting units are positioned relative to one another. In this configuration, the control device preferably determines, in particular, how far apart the two intersection points of the two central optical axes of the two lighting units with the illuminated surface are from one another. In the case of two lighting units, there is one such distance, in the case of three lighting units, there are three such distances, and in the case of four lighting units, there are already six such distances, assuming that all lighting units are switched on simultaneously and are taken into account in the prediction and, optionally, in the determination of the maximum overall irradiance. The distance between the two intersection points can naturally be zero.

[0068] Each lighting unit can be connected to a spacing sensor and an orientation sensor. The spacing sensor measures the distance between the lighting unit and the illuminated surface. The orientation sensor measures how the lighting unit's central optical axis is positioned in space. The control device uses the signals from these two sensors to determine how the light fields are positioned relative to each other.

[0069] In one configuration, two or at least two lighting units are each connected to a distance sensor. The position and orientation of the distance sensor relative to the connected lighting unit are immutable. Each of the at least two distance sensors can scan the illuminated surface without contact. The distance sensors provide at least two topographic 3D profiles of the illuminated surface, often from different viewing directions. The control device compares these topographic profiles and uses the results of this comparison to determine how the light fields of the lighting units are positioned relative to each other on the surface. Preferably, the control device additionally uses the structurally-induced positions and orientations of the distance sensors in the lighting units relative to the central optical axis of the lighting unit to derive the position and orientation of the central optical axis relative to the topographic profile. Preferably, the control device derives the distances at which the intersections of the central optical axis and the surface are separated from each other from the comparison of the two topographic profiles. In many cases, the control device can also determine the position of a third light field relative to the two first light fields, even if this third light field originates from a lighting unit that is not connected to such a distance sensor.

[0070] According to the present invention, the control device can drive and control each lighting unit of the lighting device independently of the specific other lighting unit or units. According to one implementation, the control device can drive and control the lighting units within a measurement period as follows: in a first alternative, at each time point during the measurement period, exactly one lighting unit is switched on and the specific other lighting unit or units are switched off. In a second alternative, at each time point during the measurement period, exactly one lighting unit is switched off and the specific other lighting unit or units are switched on. This measurement period is used to determine how these light fields of the lighting units are positioned relative to each other. Preferably, the frequency of switching the lighting units on and off is large enough that humans perceive continuous illumination of the surface without perceiving flicker.

[0071] According to this alternative embodiment, the lighting device includes an imaging system. The imaging system includes at least one camera. In one embodiment, one camera is arranged for each lighting unit. The imaging system is capable of generating a sequence of images of the illuminated surface. Each light field of each lighting unit is located within the field of view of at least one camera of the imaging system. The sequence is generated as follows: for each lighting unit, the sequence includes at least one image of the illuminated surface, which image was generated while the lighting unit was switched on in the first alternative and while it was switched off in the second alternative. In other words, in the first alternative, the image shows only the light field of the lighting unit, and in the second alternative, the image shows only the light fields of a specific other lighting unit or lighting units. The sequence includes at least as many images as the lighting device includes. Each image of the sequence is marked with a timestamp (time of image generation).

[0072] The control device evaluates the sequence of images. Preferably, the control device superimposes these images of the sequence on one another by calculation. The control device uses the images with their timestamps and the times at which the lighting units are respectively switched on or off to determine which light fields originate from which lighting units on which surfaces. The control device also uses this information to determine how these light fields are positioned relative to one another.

[0073] This configuration allows determining the positioning of the light field even when all lighting units emit light with the same light spectrum, and furthermore, it makes it unnecessary to measure each position and orientation of each lighting unit in space.

[0074] In one application, this configuration can additionally be used to determine the spacing between a lighting unit and the illuminated surface: the magnitude of the light field in the image and the diameter of the light field at a reference spacing of the lighting units provide an estimate of the spacing between the lighting unit and the surface.

[0075] As already mentioned, the irradiance of a lighting unit is proportional to the illuminance, with the proportionality coefficient depending on the light spectrum of the lighting unit. In one configuration, the control device determines a respective light spectrum of each lighting unit. The light spectrum of a lighting unit depends on the light spectrum resulting from the structure of the above-mentioned light source groups of this lighting unit, as well as the respective maximum irradiance of this light source group. The control device uses the determined light spectra to predict the maximum overall irradiance, and optionally determines the maximum overall irradiance actually achieved.

[0076] The maximum irradiance of a lighting unit may additionally depend on the angle at which the central optical axis of the lighting unit intersects the illuminated surface. In one configuration, the control device determines each angle for each lighting unit and uses the determined angles to predict the maximum overall irradiance, and optionally to determine the maximum overall irradiance actually achieved.

[0077] According to the invention, the control device predicts the maximum overall irradiance, and does so in response to detecting a user setting, and in case the predicted maximum overall irradiance is greater than a predetermined upper limit, the control device activates and controls at least one lighting unit, thereby preventing the upper limit from being exceeded, or at least not significantly.

[0078] Various configurations are possible in which the control device causes the upper limit not to be exceeded by the drive control.

[0079] In one configuration, the user setting relates to the maximum overall irradiance. For example, the user sets that the maximum overall irradiance to be achieved should be increased. In response to detecting this user setting, the control device preferably controls each lighting unit, optionally excluding switched-off or defective lighting units. By this control, the control device changes the respective maximum irradiance of each lighting unit according to the user setting, but so as not to exceed the upper limit. As a result of this setting, it is possible that the user setting is not realized exactly as desired, i.e., it is kept smaller than desired by the user. This configuration is particularly advantageous when the maximum overall irradiance has already reached or nearly reached the upper limit and the user sets an increase in the maximum overall irradiance. Instead, it is possible to keep the lighting device unchanged.

[0080] In one implementation of this configuration, the control device causes the drive control to change each maximum irradiance of each lighting unit by the same factor, while in another implementation, the control device causes the maximum irradiance of the lighting unit that currently achieves the highest or lowest maximum irradiance of all lighting units of the lighting device to be changed.

[0081] In another configuration, the user setting relates to a particular first lighting unit selected by the user. For example, the user wants a particular area on the illuminated surface to be illuminated more intensely, for example because a medical procedure on a patient is to be performed in this area. The user therefore sets that the maximum irradiance and / or the diameter of the light field and / or the color temperature of the first lighting unit directed towards this area should be changed, in particular increased.

[0082] Preferably, in this alternative configuration, the control device drives a first lighting unit to which a user setting relates, thereby causing the maximum irradiance of the first lighting unit to be changed, ideally in accordance with the user setting. In the case where the driving control increases the maximum irradiance of the first lighting unit in accordance with the user setting, while everything else remains unchanged, the resulting maximum overall irradiance may exceed a predetermined upper limit. According to the invention, also in this alternative configuration, the control device predicts the maximum overall irradiance that can be achieved from the realization of this user setting, i.e., in the case where the maximum irradiance of the first lighting unit is changed as set by the user.

[0083] Preferably, the control device causes the first lighting unit to be changed according to the user setting. In case this change would cause the upper limit to be exceeded, the control device selects another lighting unit and drives this other lighting unit, thereby causing the maximum irradiance of this other lighting unit to be reduced, with the aim of the maximum overall irradiance being at most equal to the upper limit. In case the lighting device includes at least three lighting units, the control device can select multiple other lighting units and reduce the respective maximum irradiance of these selected other lighting units.

[0084] This configuration allows, in many cases, as desired by the user, for a specific area on the illuminated surface to be illuminated differently, in particular more strongly, than previously, i.e., by the first lighting unit, without nevertheless exceeding the upper limit. Preferably, the control device selects at least one further lighting unit, the light field of which does not overlap, or overlaps relatively little, with the light field of the first lighting unit. It is also possible for the control device to select as the further lighting unit the lighting unit that currently achieves the maximum irradiance among all other lighting units.

[0085] At least one first lighting unit of the lighting device may be directed toward a first region of the illuminated surface, in particular toward a first region of a patient on an operating table. The first region may be particularly sensitive to thermal energy input, for example, the patient's chest or face. At least one other lighting unit may be directed toward another region less sensitive to thermal energy. Preferably, the light fields of the or each first lighting unit do not overlap, or at least do not substantially overlap, with the light fields of the or each further lighting unit. In many cases, the upper limit only needs to be observed for this first region.

[0086] In this application, it is important that the maximum overall irradiance achieved by the first lighting unit as a whole is less than or equal to the upper limit. The maximum irradiance of the second lighting unit is preferably not taken into account. This configuration allows the first area to be illuminated as brightly as possible or as desired without exceeding the upper limit.

[0087] Thus, in one configuration, the control device determines a lighting unit subset, i.e., a first lighting unit of the application just described. The lighting unit subset includes at least one lighting unit of the lighting device. At least one further lighting unit of the lighting device belongs to the remaining set, i.e., not to the lighting unit subset. The control device can determine a respective maximum irradiance of each lighting unit of the lighting unit subset. To predict the maximum overall irradiance of the lighting device, the control device uses user settings, the determined maximum irradiance of the (first) lighting units of the lighting unit subset, and optionally information on how the light fields of these first lighting units are positioned relative to each other. Preferably, the control device does not use the irradiance of the remaining lighting units.

[0088] Different implementations are possible in which the control device determines the lighting unit subset.

[0089] In one implementation, the lighting device detects a corresponding user setting. In one implementation, the user setting identifies a particular lighting unit or each lighting unit of the lighting unit subset, or in another implementation, identifies a particular lighting unit or each lighting unit of the lighting device that does not belong to the lighting unit subset. In many cases, the user can reliably set which lighting units are directed toward the heat-sensitive area.

[0090] Another implementation can be combined with the above-described configuration, in which the control device determines how the light fields of the lighting units are positioned relative to one another. According to this combination, the control device determines overlapping light fields. The lighting units that generate these overlapping light fields belong to the lighting unit subset. Each further lighting unit does not belong to the lighting unit subset, i.e. the light field of the or each further lighting unit does not overlap with the light fields of the lighting units of the lighting unit subset.

[0091] According to the present invention, the control device predicts the maximum overall irradiance and predicts the maximum overall irradiance in response to the event that a user setting is detected. This user setting relates to the maximum overall irradiance or maximum irradiance of the lighting unit. The control device designs this user setting so that the maximum overall irradiance does not exceed an upper limit. In one configuration, the control device additionally subsequently determines the maximum overall irradiance that is actually achieved and can reduce it if necessary. The process by which the control device determines the maximum overall irradiance to be achieved is triggered by the control device detecting an irradiance-related event. This irradiance-related event changes the maximum overall irradiance, or at least is suitable for changing the maximum overall irradiance. While this event has already been initiated and can only be checked later, in the present invention the user setting is checked first and then executed as described above. Typically, an irradiance-related event is caused by user intervention or user action.

[0092] According to this configuration, the control device at least approximately determines the maximum overall irradiance that the lighting device achieves on the surface in response to an irradiance-related event. If this determined maximum overall irradiance is greater than the upper limit, the control device activates and controls at least one lighting unit. The control device thereby causes the maximum overall irradiance to be (further) reduced. This configuration reduces the risk that the maximum overall irradiance will be greater than the upper limit for a relatively long period of time. Nevertheless, thanks to this configuration, it is not necessary to continuously determine the current actual maximum overall irradiance at a high scanning frequency. Rather, the maximum overall irradiance is determined anew at least as needed, i.e., when an irradiance-related event is detected, i.e., when an indication of a possible change in the actual maximum overall irradiance is detected.

[0093] In one implementation, the control device drives and controls all lighting units of the lighting device, causing each maximum irradiance of each lighting unit to be reduced, for example by the same percentage or by the same absolute value. It is also possible for the control device to only reduce the maximum irradiance of lighting units that do not belong to the above-mentioned lighting unit subset.

[0094] There are various possible configurations for which irradiance-related events the control device can detect.

[0095] In one configuration, the lighting device includes at least one spacing sensor, preferably one for each lighting unit. The or each spacing sensor can measure a measure of the spacing between itself and the illuminated surface. As an irradiance-related event, the control device detects an event in which at least one measured spacing is changed, particularly reduced, by more than a predetermined lower limit. Since the maximum irradiance of a lighting unit depends on the spacing between the lighting unit and the surface, changing the spacing of the lighting units can result in a change in the maximum overall irradiance.

[0096] In another configuration, the lighting device includes at least one contact sensor, preferably one for each lighting unit. The or each contact sensor can detect when a user touches the contact sensor and thus the connected lighting unit. For example, the contact sensor may be attached to the grip of the lighting unit. A user typically touches the lighting unit, particularly the grip of the lighting unit, to change the distance between the lighting unit and the illuminated surface and / or the orientation of the lighting unit.

[0097] According to the invention, the control device can drive and control each lighting unit independently of a particular other lighting unit or each other lighting unit, with the purpose of changing or can change the maximum irradiance of this lighting unit. By this drive control, the control device at least partially implements user settings or responds to user intervention. Furthermore, the control device at least subsequently prevents or causes the maximum overall irradiance to be less than or at most equal to a predetermined upper limit. In one configuration, the lighting device is configured such that the control device strives to prevent the maximum overall irradiance from being greater than the upper limit during the entire operation of the lighting device.

[0098] In another configuration, the lighting device is operated in two different modes: an activated limit mode and a deactivated limit mode. When the limit mode is activated, the control device operates as described immediately above, i.e., predicts a maximum overall irradiance in response to a user setting and causes the actually achieved maximum overall irradiance to be less than or equal to the upper limit. Optionally, the control device responds to the detection of an irradiance-related event when the limit mode is activated as described immediately above. When the limit mode is deactivated, the control device allows the maximum overall irradiance to be greater than the upper limit. In one configuration, the control device predicts a maximum overall irradiance even when the limit mode is deactivated, but does not drive the lighting units to prevent the upper limit from being exceeded. In the case where the maximum overall irradiance is greater than the upper limit and the limit mode is deactivated, the control device preferably outputs an appropriate message in a form that is perceptible by humans.

[0099] The lighting device is preferably capable of detecting a user input that determines whether the lighting device should be operated in an activated or deactivated restricted mode. The user may activate the restricted mode in response to a message that the upper limit has been exceeded. In response, the control device drives at least one lighting unit with the aim of reducing the maximum irradiance of the lighting unit.

[0100] In one application, the lighting device according to the invention is used to illuminate a medical operating table on which a patient to be treated is placed, in particular inside a building or vehicle.

[0101] Hereinafter, the present invention will be described with reference to examples. [Brief explanation of the drawings]

[0102] [Figure 1] 1 is a schematic cross-sectional view of a lighting device having three lighting units and one camera. [Figure 2] FIG. 2 shows an example for the three light fields achieved by the three lighting units of FIG. 1, where two light fields are superimposed. [Figure 3] FIG. 1 is a schematic diagram of a first example for a light field of two lighting units and the resulting overall light field. [Figure 4] FIG. 10 is a schematic diagram of a second example of the light fields of two lighting units and the resulting overall light field. [Figure 5] 1 is a schematic cross-sectional view of an illumination device having three illumination units and two cameras for illuminating a non-planar surface. [Figure 6] FIG. 6 is a schematic diagram of the lighting unit and illuminated surface of the arrangement of FIG. 5; [Figure 7] 7 is a schematic diagram of three images generated by one camera each in the arrangement of FIG. 6. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0103] In an embodiment, the invention is used to illuminate an object Obj in the form of an operating table, on which a patient (not shown) is placed to be treated. An illumination device 100 according to the invention illuminates a surface Ob of the operating table Obj or a surface Ob of the patient on the operating table Obj, which is facing the illumination device 100. The illumination device 100 generates a light field on the illuminated surface Ob. In the following figures, a flat surface Ob is shown in a simplified form. Naturally, the illuminated surface of a patient on the operating table Obj is not flat. Note: these figures are not necessarily drawn to scale.

[0104] The example lighting device 100 includes three lighting units 1, 2, and 3, which illuminate the operating table Obj from up to three different directions, either vertically from above or obliquely. Figures 1 and 5 show two different embodiments of the lighting device 100. Unless otherwise specified, the following description relates to the two embodiments.

[0105] Preferably, the lighting units 1, 2, and 3 are movably mounted to the ceiling and can move independently of one another. The position and orientation of each lighting unit 1, 2, and 3 in space can be changed, and preferably can be changed independently of the position and orientation of a particular other lighting unit or each other lighting unit. In one configuration, the joints of each lighting unit 1, 2, and 3 are configured so that the lighting units 1, 2, and 3 do not change their position and orientation relative to the illuminated surface Ob independently, but only in response to user intervention. In another configuration, each lighting unit 1, 2, and 3 can be locked in a desired position and orientation and unlocked again.

[0106] Each of the lighting units 1, 2, and 3 has an optical central axis. In this embodiment, the optical central axis of lighting unit 1 is the same as the geometric central axis MA.1, and the optical central axis of lighting unit 2 is the same as the geometric central axis MA.2. In this embodiment, the first lighting unit 1 is rotationally symmetrical about the central axis MA.1, and the second lighting unit 2 is rotationally symmetrical about the central axis MA.2. The third lighting unit 3 is shown only diagrammatically. Naturally, other configurations, particularly other numbers of lighting units, are possible. The lighting units 1, 2, and 3 are not necessarily rotationally symmetrical. In the orientation in which the two lighting units 1 and 2 are shown in FIGS. 1 and 5, the two central axes MA.1 and MA.2 form an angle therebetween, preferably between 25° and 70°. The two central axes MA.1 and MA.2 are located obliquely on the illuminated surface Ob and lie in the drawing plane of FIGS. 1 and 5. In the situation shown, the central axis MA.3 of the lighting unit 3 lies perpendicular to the illuminated surface Ob.

[0107] Along the central optical axes MA.1, MA.2, the illuminance and irradiance of the lighting units 1, 2 are at a maximum. More precisely, in a plane perpendicular to the central optical axes MA.1, MA.2, the illuminance and irradiance have their maximum values ​​at the intersection of the plane with the central optical axes MA.1, MA.2. The same applies to the third lighting unit 3. The maximum illuminance and maximum irradiance in the space of the lighting units 1, 2, 3 are likewise located on the central optical axes MA.1, MA.2. The intersections S.1 and S.2 of the two central optical axes MA.1, MA.2 with the illuminated surface Ob are shown in FIGS. 1 and 5.

[0108] FIG. 2 shows three light fields Lf1, Lf2, and Lf3, which lighting units 1, 2, and 3 generate on the illuminated surface Ob in various possible situations. The illuminated surface Ob is located in the drawing plane of FIG. 2, and two central axes MA.1 and MA.2 are positioned obliquely relative to the drawing plane. Two ellipses are shown whose illuminance and thus irradiance are 10% of the respective maximum illuminance and irradiance on the surface Ob. Inside these ellipses, the illuminance and irradiance are greater than 10% of their respective maxima, while outside they are less than 10%. The interiors of these two ellipses are marked with different dots for illustrative purposes. The central axis MA.3 of the third lighting unit 3 is positioned perpendicular to the illuminated surface Ob in the illustrated situation, so the area where the irradiance is 10% of the maximum irradiance is a circle. In the illustrated situation, this circle does not overlap with the two ellipses of the two lighting units 1 and 2. For example, the two lighting units 1 and 2 illuminate the chest region of the patient, and lighting unit 3 illuminates the legs. In other possible situations, not shown, the two light fields overlap approximately concentrically.

[0109] Due to the orientation of the three lighting units 1, 2, 3 relative to the illuminated surface Ob, the illuminated surface Ob, and thus the patient on the operating table Obj, is illuminated from three different directions. Thus, the patient is usually still illuminated even if an object, e.g., a body part of the doctor or an object, enters the area between the lighting device 100 and the illuminated surface Ob.

[0110] The first lighting unit 1 comprises a support 5.1 and a plurality of individual light sources 1.1, 1.2, ..., which are mounted on the support 5.1 and preferably arranged rotationally symmetrically around a central axis MA.1 (see Figures 1 and 5). The second lighting unit 2 comprises a support 5.2 and a plurality of individual light sources 2.1, 2.2, ..., which are mounted on the support 5.2 and preferably arranged rotationally symmetrically around a central axis MA.2. Figures 1 and 5 show the light beams Lb of the light sources 1.1, 1.2, ... 1.1 ,Lb 1.2 and the light rays Lb of light sources 2.1, 2.2, ... 2.1 ,Lf 2.2 , ..., and are shown schematically. For illustrative purposes, the light rays are marked with different dots. The light sources can emit light of the same color temperature or at least two different color temperatures.

[0111] Each ray Lb 1.1 ,Lb 1.2 ,…,Lb 2.1 ,Lf 2.2 , ... generate individual light fields on the illuminated surface Ob. The individual light fields of the light sources of lighting units 1, 2, 3 are superimposed on the illuminated surface Ob to form one light field Lf1, Lf2, Lf3 respectively. The individual irradiances for one point on the illuminated surface Ob are thus summed. The lighting device 100 generates an overall light field Lf ges is achieved on the surface Ob.

[0112] Based on the two examples in Figs. 3 and 4, the generated overall light field Lf ges3A and 4B. The lighting units 1 and 2 are switched on, and the lighting unit 3 is switched off. The illuminated surface Ob is perpendicular to the drawing planes of FIGS. 3A, 3B and the lower drawing plane of FIG. 4B, and the central optical axes MA.1 and MA.2 lie in these drawing planes. Conversely, the illuminated surface lies in the drawing plane of FIG. 4A. In FIG. 3A, the two lighting units 1 and 2 and the two central axes MA.1 and MA.2 are shown schematically. In FIGS. 3A and 4B, the respective irradiance Ee is plotted on the surface Ob on the y-axis. The cross-section through the two light fields Lf1 and Lf2 of the two lighting units 1 and 2 and the overall light field Lf ges A cross section through and is shown. For simplicity, the two light fields Lf1 and Lf2 are shown rotationally symmetric with respect to the respective central axes MA.1 and MA.2, and the influence of the obliquely positioned central axes MA.1 and MA.2 is ignored. Figure 4 shows another example in which the two light fields Lf1 and Lf2 only slightly overlap.

[0113] The lighting device 100 further comprises an operating unit 9, which is shown only diagrammatically, and a signal processing control unit 10, which is also shown only diagrammatically. The operating unit 9 can receive user input and forward it to the control unit 10, which in turn detects this user input. Preferably, the operating unit 9 allows a user to set settings for different parameters of the lighting units 1, 2, 3 or of the lighting device 100 as a whole.

[0114] In particular, the user can set the desired maximum illuminance in the space for each lighting unit 1, 2, 3, respectively, for example, on a continuous scale or on a graduated scale from 0 to 10, with the value 10 corresponding to the maximum achievable illuminance in the space. With a value of 5, the actual maximum achievable illuminance in the space is equal to half of the maximum achievable illuminance. Alternatively, the user can set the increase or decrease to be made. By way of example, minus and plus keys are shown. Furthermore, the user can set the desired light field diameter d for each lighting unit 1, 2, 3, respectively. x and optionally settings that also define the average light spectrum of lighting units 1, 2, and 3. The desired light field diameter d x relates to a reference spacing of e.g. 1 m. In one configuration, the user can further set whether these lighting units 1, 2, 3 should be included in the automatically performed limitation of the overall irradiance. Furthermore, the user can select or deselect lighting units 1, 2, 3 using the operating unit 9, as will be explained further below.

[0115] The user can further define the following parameters for the lighting device 100: An upper limit on the maximum overall irradiance that the lighting device 100 achieves on the illuminated surface Ob and · Whether restricted mode should be activated or deactivated

[0116] The meaning will be explained further below.

[0117] The control device 10 receives user settings and drives and controls the light sources of the lighting units 1, 2, and 3 according to these settings. For example, the control device 10 sets the intensity of the current flowing through the light sources 1.1, 1.2, ..., 2.1, 2.2, ... or the voltage applied to the light sources 1.1, 1.2, ..., 2.1, 2.2, ... to appropriate values. Preferably, the light sources 1.1, 1.2, ..., 2.1, 2.2, ... are operated in a pulsed manner, with a high pulse frequency so that a viewer perceives constant illumination. The control device 10 can also change the illuminance of the light sources 1.1, 1.2, ..., 2.1, 2.2, ... by modulating the pulse width. In pulse width modulation, the control device changes the ratio between the duration of a pulse through which current is supplied to the light source and the duration of the period between two consecutive pulses. In one configuration, the control device 10 can change the illuminance of each light source independently of the illuminance of the other light sources.

[0118] In this embodiment, the control device 10 has read access to a computer-evaluable table that stores the maximum achievable illuminance in the space resulting from each of the lighting units 1, 2, and 3 for a number of possible user-configurable settings. For example, a setting of 10 on a scale of 1 to 10 may result in a desired maximum illuminance in the space of 160 kLux, which is equal to the maximum achievable illuminance, while a setting of 5 may result in half the maximum achievable illuminance, i.e., 80 kLux. This table is created and stored during a previous calibration of the lighting units 1, 2, and 3. This table is preferably valid for each similar lighting unit 1, 2, and 3 and is stored in the data memory of the lighting units 1, 2, and 3. In cases where the lighting device 100 includes lighting units 1, 2, and 3 configured differently, different tables are preferably also stored. Preferably, the tables for the lighting units 1, 2, 3 also store which settings for the light sources of the lighting units 1, 2, 3 result in the desired maximum illuminance in the space. These tables are created and stored in advance. The control device 10 has read access to these tables.

[0119] The control device 10 "knows" and uses, for each lighting unit 1, 2, 3, a respective value for each of the following parameters, which value is independent of the position and orientation of the lighting unit 1, 2, 3 relative to the surface Ob: · Maximum achievable illumination and / or irradiance in the space Functional dependence of the maximum illuminance and / or irradiance on the surface Ob on its spacing along the optical axis Optionally, the light spectrum Diameter d of the light field at the reference interval x and Whether lighting units 1, 2, and 3 should be included in the overall irradiance limit

[0120] The maximum irradiance achieved in the space of lighting units 1, 2, and 3 is Ee max,1,sp ,Ee max,2,sp ,Ee max,3,sp is shown by

[0121] In one configuration, the user can determine the maximum irradiance Ee of each lighting unit 1, 2, 3 in the space. max,1,sp ,Ee max,2,sp ,Ee max,3,sp The control device 10 can drive and control each lighting unit 1, 2, 3 accordingly. For example, a setting of 10 provides the maximum achievable illuminance in the space, and a setting of 5 provides half of that. In one configuration, a proportionality coefficient between the maximum irradiance and the maximum illuminance, e.g., 4 W / m 2 / kLux is stored. Then, the setting value 10 is, for example, 640 W / m 2In one development, a table is stored which provides the resulting proportionality coefficients between the maximum irradiance and the maximum illuminance in the space for a number of possible light spectra of the lighting units 1, 2, 3. The control device 10 also provides for each lighting unit 1, 2, 3 the maximally achieved or maximally expected irradiance in the space of the lighting unit 1, 2, 3 from the respective setting value, the maximally achievable illuminance in the space and the proportionality coefficient.

[0122] Hereinafter, for short, the "maximum overall irradiance" Ee is used to refer to the maximum irradiance caused or expected by the lighting device 100 on the illuminated surface Ob. max,ges The name is used.

[0123] The control device 10 may, in one application, determine what maximum overall irradiance Ee the lighting device 100 will provide at the illuminated surface Ob. max,ges More precisely, the control device 10 automatically determines whether the maximum irradiance Ee max,ges Estimated value Ee for max,ges,est The control device 10 calculates the estimated value Ee using a constant sampling frequency. max,ges,est In a preferred implementation, the control device 10 determines the maximum overall irradiance Ee each time an irradiance-related event is detected. max,ges The irradiance-related events are the maximum overall irradiance Ee max,ges or change the maximum overall irradiance Ee max,ges Examples of irradiance-related events are: The distance between the lighting units 1, 2, 3 and the surface is changed, in particular reduced. A user touches the support of the lighting unit 1, 2, 3: this touch is usually performed with the purpose of changing the position and / or orientation of this lighting unit 1, 2, 3 relative to the surface.

[0124] Preferably, the lighting device 100 includes a sensor capable of detecting irradiance-related events. The signal of such a sensor is transmitted to the control device 10. In another application, the control device 10 may be configured to determine what the maximum overall irradiance Ee of the lighting device 100 is. max,ges is expected in response to the user settings, or more precisely: what maximum overall irradiance Ee of the lighting device 100 is achieved or would be achieved in the case where the user settings are not changed? max,ges automatically predicts what will or will not occur in response to user settings.

[0125] The maximum total irradiance Ee currently achieved by the lighting device 100 on the illuminated surface Ob is max,ges In this embodiment, the control device 10 uses the current drive control of the lighting units 1, 2, 3 and further sensor values ​​to at least approximately determine the maximum overall irradiance Ee that the lighting device 100 would achieve if the user settings were implemented unchanged. max,ges The control device 10 uses this user setting, and otherwise the actual driving control of the lighting units 1, 2, 3, to at least approximately predict the maximum irradiance Ee max,1,sp should be increased to a maximum value, the control device 10, for this prediction, max,1,sp Use this maximum value for the actual current light field diameter and current correlated color temperature of lighting unit 1, as well as the currently achieved respective maximum irradiance, maximum light field diameter and correlated color temperature of the other two lighting units 2 and 3. Note: User settings that change the light field diameter or correlated color temperature of lighting units 1, 2, and 3 also affect the maximum overall irradiance Ee max,ges This results in an increase in

[0126] The data memory of the lighting device 100 stores the maximum overall irradiance Ee max,ges The maximum allowable upper limit for the2 or 1000W / m 2 These values ​​are derived from the above-mentioned standards for individual medical lighting units. Note: The above-mentioned standards specify upper limits for individual lighting units, but not for lighting systems with multiple lighting units.

[0127] The user can set a lower value for this limit, but cannot set a higher value for this limit. The limit used, i.e., from the factory or set by the user, is the Ee max,req The control device 10 determines the determined or predicted maximum overall irradiance Ee max,ges The upper limit is Ee max,req Compare with.

[0128] In all possible applications, the lighting device 100 is always operated in limited mode. The control device 10 determines the maximum overall irradiance Ee that can actually be achieved. max,ges is always the upper bound Ee max,req It automatically ensures that the user setting is below the upper limit Ee max,req In cases where this would result in the upper limit Ee being exceeded, the control device 10 will max,req This is explained below using an example where the user has the following settings: the maximum irradiance Ee in the space of the lighting unit 1 max,1,sp should be increased, for example, to a maximum value. In the case where this user setting is implemented and all the remaining settings of lighting units 1, 2, 3 remain unchanged, the upper limit Ee max,req In one implementation, the control device 10 responds to this prediction by adjusting the maximum irradiance Ee of the lighting unit 1. max,1,sp In another preferred embodiment, the control device 1 increases the maximum irradiance Ee in the space of the lighting unit 1 as little as desired by the user, and in extreme cases does not increase it at all. max,1,sp as specified by the user settings, but with the maximum irradiance Ee of another lighting unit 2 or 3.max,2,sp ,Ee max,3,sp is reduced, which results in an upper limit Ee max,req This ensures that no excess occurs.

[0129] In another possible application, this limiting mode is selectively activated or deactivated, for example by the user using the operating unit 9 or automatically by the control device 10. If the limiting mode is deactivated, the control device 10 limits the maximum overall irradiance Ee max,ges is the upper limit Ee max,req Preferably, the control device 10 does not prevent the predicted or determined maximum overall irradiance Ee max,ges is the upper limit Ee max,req If the threshold voltage is greater than 100 V, an alarm is generated. This alarm is output in a form that can be perceived by a human.

[0130] As already mentioned, the user can select at least one lighting unit 1, 2, 3 of the lighting device 100. In Figures 1 and 5 three keys labeled 1, 2, 3 on the operating unit 9 are shown diagrammatically. The control device 10 controls the maximum overall irradiance Ee of the lighting device 100. max,ges Alternatively, the control device 10 only considers the selected plurality of lighting units 1, 2, 3 or each selected lighting unit 1, 2, 3 when determining or predicting the lighting unit number 1, 2, 3.

[0131] By way of example, an application will be described for the case where the user selects lighting unit 3. Lighting units 1 and 2 are directed, for example, towards the patient's chest or face, and light fields Lf1 and Lf2 overlap there. Lighting unit 3 illuminates the patient's legs, and the light field Lf3 of lighting unit 3 does not overlap with light fields Lf1 and Lf2. In this application, the maximum irradiance that lighting units 1 and 2 together produce on the patient's chest or face is limited to an upper limit Ee max,reqThe lighting unit 3 does not illuminate the chest or face, but illuminates less sensitive areas of the patient and is not included in the maximum overall irradiance limit.

[0132] In the configuration described below, all three lighting units 1, 2, 3 are included in the overall irradiance prediction, i.e. the user has not selected or deselected any lighting units.

[0133] Maximum overall irradiance Ee max,ges depends in particular on the following parameters: The respective maximum illuminances achieved by lighting units 1, 2, and 3 on surface Ob, and How the light fields Lf1, Lf2, Lf3 that lighting units 1, 2, 3 achieve on surface Ob are positioned relative to each other

[0134] The maximum irradiance achieved on the surface Ob is Ee max,1 ,Ee max,2 ,Ee max,3 and is equal to or less than the maximum irradiance achieved in the space by the lighting units 1, 2, and 3. In this example, the maximum irradiance Ee max,1 ,Ee max,2 ,Ee max,3 occurs on each of the optical central axes MA.1, MA.2, MA.3.

[0135] 2, 3 and 4 show several examples of how the two light fields Lf1 and Lf2 of the two lighting units 1 and 2 are positioned relative to each other. max,1 and Ee max,2 , the resulting overall light field Lf ges and maximum overall irradiance Ee max,ges , i.e., this total light field Lf on the illuminated surface Ob ges The maximum irradiance is shown.

[0136] The control device 10 determines the maximum overall irradiance Ee currently achieved or expected. max,ges This estimate is Ee max,ges,est To determine the estimate, the control device 10 uses the respective values ​​of at least one of the above-mentioned parameters, optionally each of the above-mentioned parameters, which are independent of the position and orientation of the lighting units 1, 2, 3 relative to the illuminated surface Ob, in particular due to the structure and therefore independent of the predetermined parameters and the drive control of the lighting units 1, 2, 3. The control device 10 calculates this estimate Ee max,ges,est The upper limit is Ee max,req Compare with.

[0137] In various configurations of the invention, the control device 10 may further determine values ​​for none of the following parameters, or for one or more of the following parameters, which depend on the current position and orientation of the lighting units 1, 2, 3 relative to the illuminated surface Ob, and may calculate the estimated value Ee max,ges,est Using a particular, or at least one, preferably each determined parameter value, to determine: the respective distances between each of the illuminating devices 1, 2, 3 and the surface Ob measured along each of the optical central axes MA.1, MA.2, MA.3; The distance between the two intersections of the two optical central axes MA.x, MA.y (y#x) with the surface Ob The diameter d of each light field achieved by each lighting unit 1, 2, 3 on the illuminated surface Ob x Other characteristics of each light field Lf1, Lf2, Lf3 of each lighting unit 1, 2, 3 whether at least two light fields on the illuminated surface Ob overlap, and The angle between the central optical axis of the lighting units 1, 2, 3 and the plane in which the surface Ob extends.

[0138] In the following, we will first describe an arrangement in which the control device 10 does not determine or use values ​​for any of the above parameters that are dependent on position and / or orientation. Instead, two simplifying assumptions are made. These two simplifying assumptions allow the determined estimate Ee max,ges,est is always the actual maximum overall irradiance Ee max,ges is equal to or greater than the actual maximum overall irradiance Ee max,ges Not smaller. "That is, be on the safe side."

[0139] This simplification is that the respective maximum illuminance and therefore irradiance in space of each lighting unit 1, 2, 3 occurs on the illuminated surface Ob. Another simplification is that all central optical axes MA.1, MA.2, MA.3 intersect the surface Ob at the same point. Result: the three generated light fields Lf1, Lf2, Lf3 are positioned concentrically with each other. On the flat surface Ob, the three generated light fields Lf1, Lf2, Lf3 are concentric ellipses, in particular circles.

[0140] These two simplifications, in particular, eliminate the need to measure or otherwise determine the spacing between the lighting units 1, 2, 3 and the surface Ob and the relative positioning of the light fields Lf1, Lf2, Lf3 with respect to one another, and allow the control device 10 to calculate the estimated value Ee max,ges,est is calculated as the sum of the maximum irradiance in the space, i.e. (1) Ee max,ges,est =Ee max,1,sp +Ee max,2,sp +Ee max,3,sp This becomes possible.

[0141] The configurations according to Figures 3 and 4 are two examples, where the above assumptions lead to the control device 10 setting an excessively low illuminance and therefore irradiance in at least one lighting unit 1, 2, 3, i.e. the illuminance of the lighting unit 1, 2, 3 and the resulting maximum overall irradiance Ee max,ges and the upper limit is Ee max,reqTherefore, the illuminance / irradiance of at least one lighting unit 1, 2, 3 may be less than desired by the user. In the following, several configurations are described that avoid the need for the simplification just described.

[0142] In one configuration, the user additionally configures which lighting units 1, 2, 3 generate or possibly generate overlapping light fields. The simplifications just described are preferably used for lighting units that generate overlapping light fields according to the configuration. The maximum irradiance generated by these lighting units with overlapping light fields is generated according to the simplifications just described. Depending on which value is larger, the maximum overall irradiance Ee max,ges,est This maximum irradiance in the space or the maximum irradiance of other lighting units in the space is used as .

[0143] An example is valid for the situation shown in Figures 2 and 3. According to this example, the light fields Lf1, Lf2 of the two lighting units 1 and 2 overlap, and the light field Lf3 of the lighting unit 3 does not overlap. Then, the maximum overall irradiance Ee max,ges,est An estimate for is found or predicted as follows: (2) Ee max,ges,est =max[Ee max,1,sp +Ee max,2,sp ,Ee max,3,sp ]

[0144] This estimate "still puts us on the safe side."

[0145] The configuration described below eliminates the need for the user to configure which light fields are overlapping or can be overlapped. This preferred configuration is described below. The configuration described below can also use the assumptions just described, i.e., for example, the maximum overall irradiance Ee max,ges,est is found or predicted according to equation (2).

[0146] A first camera 4.1 is mounted on a support 5.1 (see FIGS. 1 and 5). The area of ​​the illuminated surface Ob, illuminated by at least one lighting unit 1, 2, is located in the field of view Bf.1 of the first camera 4.1. In the configuration according to FIG. 5, a second camera 4.2 is additionally mounted on a support 5.2. This illuminated area is additionally located in the field of view Bf.2 of the second camera 4.2. It is also possible for one camera to be mounted on a separate support.

[0147] A first camera 4.1 and an optional second camera 4.2 each generate an image of the illuminated surface Ob, which may look similar to those shown in Figures 2 and 4, for example.

[0148] The light fields Lf1, Lf2, and Lf3 are also shown in the images from camera 4.1 or the two cameras 4.1 and 4.2. However, it is still not clear from the images from cameras 4.1 and 4.2 which light fields come from which lighting units.

[0149] The control device 10 can determine which light field originates from which lighting unit from the image of the camera 4.1, optionally from the images of the two cameras 4.1, 4.2, and from the signals of these three sensors. Preferably, the control device 10 further determines the diameter d of each light field set in the lighting units 1, 2, 3. x Use.

[0150] In the following, it will be explained for a first implementation how the control device 10 detects permanently or at least at regular intervals which light fields Lf1, Lf2, Lf3 originate from which lighting units 1, 2, 3. During the measurement period in which this detection is carried out, the three lighting units 1, 2, 3 (more generally: the currently used lighting units) are operated in a pulsed manner and as follows: In a first alternative of the first realisation mode, exactly one lighting unit 1, 2, 3 is switched on at each time, while all other lighting units are switched off. During this period, each lighting unit 1, 2, 3 is switched on at least once, preferably multiple times. In a second alternative, at each time exactly one lighting unit 1, 2, 3 is switched off and all other lighting units are switched on. During this period, each lighting unit 1, 2, 3 is switched off at least once, preferably multiple times. The second realization will in many cases result in a higher irradiance than the first realization.

[0151] Preferably, the measurement period is short enough that the position and orientation of each lighting unit does not change substantially relative to the surface during the measurement period. In two alternatives, the pulse frequency is preferably high enough that an observer perceives the three lighting units 1, 2, 3 as permanently switched on and illuminating, i.e., no flickering is perceived.

[0152] The first camera 4.1, and in one configuration also the optional second camera 4.2, each capture a sequence of images, where the following boundary conditions are observed: at least one image of the sequence shows only the first light field Lf1, at least one image shows only the second light field Lf2, and at least one image shows only the third light field Lf3. The control device 10 evaluates these images, which the control device 10 preferably superimposes by computation. The control device 10 derives at least one of the following information from the evaluation: The diameter d of each light field actually achieved on the surface Ob for each lighting unit 1, 2, 3 x (This is the diameter d of the light field at the reference interval x (It may deviate from Whether light fields Lf1, Lf2, and Lf3 overlap, and if so, how strongly they overlap The mutual spacing of the points of maximum illumination and / or the centers of the light fields Lf1, Lf2, Lf3 on the surface Ob How the maximum irradiance areas of lighting units 1, 2, and 3 are positioned relative to each other on surface Ob

[0153] To determine which light fields Lf1, Lf2, Lf3 originate from which lighting units 1, 2, 3, the control device 10 determines, in a first alternative, which light fields would be shown in the image if lighting unit x (x=1, 2, 3) were switched on and each other lighting unit y (y#x) were switched off. Correspondingly, in a second alternative, the control device 10 determines which light fields would not be shown. By image processing, the control device 10 determines which lighting units 1, 2, 3 generate the currently superimposed light fields.

[0154] In a second implementation, at least one lighting unit 1, 2, 3, preferably each lighting unit 1, 2, 3, includes a sensor that measures the current position and orientation of the lighting unit 1, 2, 3 in space. The control device 10 uses the signals of these sensors to determine which light field originates from which lighting unit 1, 2, 3.

[0155] The two implementations can be combined with each other. The first implementation with two alternatives has the advantage that no sensors are needed to measure the position or orientation of the lighting units 1, 2, 3 in space.

[0156] In the configuration just described, the maximum irradiance Ee of each of the lighting units 1, 2, and 3 in the space is max,1,sp ,Ee max,2,sp ,Ee max,3,spis the maximum irradiance Ee of this lighting unit 1, 2, 3 on the surface Ob max,1 ,Ee max,2 ,Ee max,3 This configuration often results in an upper limit of Ee max,req The maximum overall irradiance Ee is significantly lower than max,ges Therefore, preferably, the respective distances dist1, dist2, dist3 between the lighting units 1, 2, 3 and the illuminated surface Ob are measured and used.

[0157] In a preferred configuration, the lighting units 1, 2, 3 achieve a maximum irradiance Ee on the illuminated surface Ob. max,1 ,Ee max,2 ,Ee max,3 It is valid to assume that the maximum irradiance Ee occurs at each intersection between the central optical axes MA.1, MA.2, MA.3 of the lighting units 1, 2, 3 and the surface Ob, regardless of the angle formed between the central optical axes MA.1, MA.2, MA.3 and the operating table Obj, and thus between the central optical axes MA.1, MA.2, MA.3 and the surface Ob. In the example shown in Figures 2 to 4, this is max,1 ,Ee max,2 occurs at the intersection S.1 or S.2. This assumption is especially important when 50 >d 10 This is effective when

[0158] Under this assumption, only the distances dist1, dist2 along the optical central axis between the lighting units 1, 2, 3 and the illuminated surface Ob need to be measured. The control device 10 has read access to a respective computer-evaluable table for each lighting unit 1, 2, 3. This table contains the maximum irradiance Ee in space for various distances. max,1,sp ,Ee max,2,sp ,Ee max,3,sp and the maximum irradiance Ee on the surface Ob max,1 ,Ee max,2 ,Ee max,3and are stored. Preferably, the proportionality coefficients are valid for each of the lighting units 1, 2, and 3. Of course, one proportionality coefficient may be stored for each of the lighting units 1, 2, and 3 for various intervals.

[0159] In one configuration, the control device 10 determines and uses the respective spacings dist1, dist2, dist3 between the lighting units 1, 2, 3, but using the simplifying assumption that the light fields Lf1, Lf2, Lf3 are arranged concentrically with one another. The control device 10 determines the respective maximum irradiance on the surface Ob, and calculates the maximum overall irradiance Ee according to, for example, the following calculation rules: max,ges Estimated value Ee max,ges,est Derive: (3) Ee max,ges,est =Ee max,1 +Ee max,2 +Ee max,3

[0160] In the case where it is set or required that the light field Lf3 of the lighting unit 3 does not overlap with the other two light fields Lf1, Lf2, the following calculation rule is also possible: (4) Ee max,ges,est =max[Ee max,1 +Ee max,2 ,Ee max,3 ]

[0161] An object, for example, an instrument or a body part of a treating physician, may reach the area between the lighting units 1, 2, 3 and the illuminated surface Ob. If the central optical axes MA.1, MA.2, MA.3 extend through this object, the control device 10 automatically detects this event, since the distance measured along the central axes MA.1, MA.2, MA.3 decreases suddenly. The control device 10 preferably uses the value measured before this decrease as the distance between the lighting units 1, 2, 3 and the surface Ob.

[0162] In the following, various configurations will be described for measuring the distances MA.1, MA.2, MA.3 along the central optical axis.

[0163] In one configuration, at least one distance sensor is attached to each of the supports 5.1, 5.2, and 5.3. This distance sensor measures the distance between itself and the reflective, illuminated surface Ob. In the example of FIG. 1, such a distance sensor 6.2 is shown attached to the support 5.2 of the second lighting unit 2 and measuring the distance dist2 between itself and the illuminated surface Ob along the central axis MA.2. Preferably, each of the supports 5.1, 5.2, and 5.3 is attached to at least one distance sensor. A lateral distance may occur between the distance sensor and the central axis MA.1, MA.2, or MA.3. This distance, as well as the angle between the central axis MA.1, MA.2, or MA.3 and the axis along which the distance sensor measures the distance, are known from the configuration of the lighting units 1, 2, and 3. Preferably, the control device 10 can correct the distance sensor measurement using this distance and angle to determine the distance along the central axis.

[0164] In one implementation, the first camera 4.1 and / or the optional second camera 4.2 each have an autofocus function that focuses the cameras 4.1, 4.2 on the illuminated surface Ob. In one implementation, the control device 10 uses this autofocus setting to determine each interval. The control device 10 can receive multiple measurements of the intervals from multiple sensors and aggregate these measurements into an interval.

[0165] As already explained, the control device 10 determines the diameter d of each light field of each lighting unit 1, 2, 3. x , e.g., d 10 The diameter of this light field d x is related to a predetermined reference distance, for example 1 m. Preferably, the control device 10 "knows" the respective imaging scale of the particular camera used or of each camera 4.1, 4.2 used. The diameter d of the light field xand the imaging scale defines how large the images of the light fields Lf1, Lf2, Lf3 of the lighting units 1, 2, 3 are when the planes of the light fields Lf1, Lf2, Lf3 are positioned perpendicular to the central optical axes MA.1, MA.2, MA.3 and at a reference distance from the lighting units 1, 2, 3. In one configuration, the control device 10 derives estimates of the distances dist1, dist2, dist3 between the lighting units 1, 2, 3 and the surface Ob measured along the central axes MA.1, MA.2, MA.3 from this size and the actual size in the images of the cameras 4.1, 4.2. It is also possible for the control device 10 to measure the size of the images of the light fields in the images of the cameras 4.1, 4.2. The size of the images and the diameter d of the light fields at the reference distance are used to calculate the distances dist1, dist2, dist3 between the lighting units 1, 2, 3 and the surface Ob measured along the central axes MA.1, MA.2, MA.3. x From this, the control device 10 derives the distances to be searched between the cameras 4.1, 4.2, and thus the lighting units 1, 2, and the light fields Lf1, Lf2, Lf3, and thus the illuminated surface Ob. Optionally, the control device 10 uses an imaging scale of the cameras 4.1, 4.2 that can be changed in the implementation of the cameras 4.1, 4.2.

[0166] It is possible for at least one lighting unit 1, 2, 3 to include a dedicated camera and / or other dedicated distance sensor, and for at least one other lighting unit not to include a dedicated camera or other dedicated distance sensor. Nevertheless, in many cases, the distances are measured at least approximately. This implementation will be described below with reference to the exemplary situation shown in Figure 1. In this situation, only the second lighting unit 2 has a distance sensor 6.2, and therefore only the distance dist2 between the second lighting unit 2 and the illuminated surface Ob can be measured directly.

[0167] 1, the control device 10, in one implementation, uses the image of the camera 4.1 with the field of view Bf.1 to determine the size and position of each of the light fields Lf1, Lf2, Lf3 on the illuminated surface Ob. The control device 10 further determines the geometric shape of each of the lighting units 1, 2, 3 and the diameter d of each light field. x Furthermore, the control device 10 "knows" the diameter of the circular area that the light sources 1.1, 1.2, ..., 2.1, 2.2, ... occupy as a whole on the supports 5.1, 5.2, 5.3, i.e., the diameter of each light ray generated on the supports 5.1, 5.2, 5.3. For each lighting unit 1, 2, 3, the control device 10 determines the respective ratio between the diameter of the light field at the lighting unit 1, 2, 3 and the diameter of the light fields Lf1, Lf2, Lf3 that the lighting unit 1, 2, 3 generates on the illuminated surface Ob. From these ratios and the measured distance dist2, the control device 10 approximately determines the remaining distance.

[0168] In the case of lighting units 1, 2, 3 that do not have a distance sensor, the following simplifying assumption is also possible: the actual distances dist1, dist2, dist3 between the lighting units 1, 2, 3 are equal to the reference distances mentioned above, which are for example 1 m.

[0169] As already explained, the control device 10 determines the maximum irradiance Ee of each of the lighting units 1, 2, 3 on the surface Ob. max,1 ,Ee max,2 ,Ee max,3 To determine the distances between the lighting units 1, 2, 3 and the illuminated surface Ob, the distances are used, for example measured along the central axes MA.1, MA.2, MA.3.

[0170] In one configuration, the maximum illuminance Ee generated by the lighting units 1, 2, and 3 on the surface Ob is max,1 ,E emax,2 ,Ee max,3occurs at the intersection S.1, S.2, S.3 between the central optical axes MA.1, MA.2, MA.3 of the lighting units 1, 2, 3 and the illuminated surface Ob, regardless of the angle between the central axes MA.1, MA.2, MA.3 and the surface Ob. The following construction avoids the need to assume this simplifying assumption and takes into account the possibility that the central axes MA.1, MA.2, MA.3 are not perpendicular to this surface but lie obliquely, and therefore the maximum irradiance, even for bell-shaped light fields Lf1, Lf2, Lf3, occurs outside the intersection of the central axes with the surface. It can be assumed that the illuminated surface Ob extends within a single plane.

[0171] An arrangement has been described above in which one sensor each measures the current orientation of the lighting units 1, 2, 3 in space. In one arrangement, the control device 10 derives the angle between the central axes MA.1, MA.2, MA.3 and the surface Ob from the signals of the sensors. An alternative arrangement eliminates the need for such sensors. This alternative arrangement is described below with reference to Figures 5 to 7.

[0172] In this configuration, at least one camera 4.1, preferably two cameras 4.1, 4.2, are configured as so-called 3D cameras. The cameras 4.1, 4.2 have a field of view Bf.1 or Bf.2 and not only provide a brightness value as a grayscale or color value for each image point, but also measure, for each image point, or at least for a sufficient number of image points, the distance between the image point and the illuminated surface Ob in the direction of a central optical axis MA.1, MA.2 of the cameras 4.1, 4.2. In the illustrated example, this central optical axis coincides with the central axis MA.1, MA.2 of the lighting units 1, 2.

[0173] The illuminated surface Ob typically does not have a flat contour. By way of example, five protuberances 7.1, ..., 7.5 are shown in Figures 5 to 7. The cameras 4.1, 4.2 scan the illuminated surface Ob without contact, thereby achieving a topographic profile of the surface Ob in the viewing directions MA.1, MA.2. Such cameras are known under the name "time-of-flight sensors." Such methods are described, for example, in German Patent Applications DE 102013012231 A1 and DE 102012014716 A1. Other configurations for the sensors generating the topographic profile are also possible, such as suitable laser scanners, radar scanners, or lidar scanners. The sensors generating the topographic profile can also be spatially separated from the cameras 4.1, 4.2.

[0174] FIG. 5 shows how two 3D cameras 4.1 and 4.2 generate topographical profiles of the illuminated surface Ob, each including these five ridges 7.1, ..., 7.5, from two different viewing directions. FIG. 6 shows how the second lighting unit 2 is positioned relative to the illuminated surface Ob. FIG. 7A shows how the five ridges 7.1, ..., 7.5 appear in the topographical profile when the optical axis of the camera is perpendicular to the illuminated surface Ob, which is not the case for the two cameras 4.1 and 4.2. FIG. 7B shows how the five ridges 7.1, ..., 7.5 appear in the topographical profile of camera 4.2 at the support 3.2 of the second lighting unit 2. FIG. 7C shows how the five ridges 7.1, ..., 7.5 appear in the topographical profile of camera 4.1. Here, it is known that the closer the ridges 7.1, . . . , 7.5 are to the respective cameras 4.1, 4.2, the larger the ridges 7.1, . . . , 7.5 will appear.

[0175] The topographical profiles of the two cameras 4.1 and 4.2 show the same illuminated surface Ob from two different observation directions. Optionally, there is additionally a topographical profile of a 3D camera (not shown) whose optical axis is positioned perpendicular to the illuminated surface Ob.

[0176] The control device 10 "knows" the positions of the 3D cameras 4.1, 4.2 relative to the central optical axes MA.1, MA.2. From this data, the control device 10 automatically derives the positions of the central axes MA.1, MA.2 relative to each topography profile provided by the cameras 4.1, 4.2. By evaluating the topography profiles and the positions of the central axes MA.1, MA.2, the control device 10 derives the spacing between the lighting units 1, 2 and the illuminated surface Ob, measured along the central axes MA.1, MA.2. By a computational comparison between these topography profiles, the control device 10 determines the spacing between the two central axes MA.1, MA.2 and the two intersection points S.1 and S.2 of the illuminated surface Ob. From this, and at the reference spacing, the diameter d of each light field of the lighting units 1, 2 is calculated. x From this, the control device 10 derives how strongly the two light fields Lf1 and Lf2 overlap (see FIGS. 2 to 4).

[0177] In one configuration, the control device 10 further determines the respective angles between the central axes MA.1, MA.2 and the plane in which the illuminated surface Ob extends. For example, the control device 10 performs a coordinate transformation by calculation to superimpose two topographic profiles on each other. These two profiles represent the same surface Ob. From the comparison, for example from the coordinate transformation, the control device 10 derives the angle between the two central optical axes MA.1, MA.2 of the lighting units 1, 2.

[0178] When another object enters the field of view Bf.1, Bf.2 of the cameras 4.1, 4.2, the particular topographic profile or at least one of the topographic profiles measured by the 3D cameras 4.1, 4.2 changes suddenly. The control device 10 automatically detects this event. To detect this event, the control device 10 preferably uses a current topographic profile, which preferably comprises the topographic profile last measured before the detection of this event. In most cases, this topographic profile of the illuminated surface Ob does not change unless an object is present in the field of view Bf.1, Bf.2 and another object enters the field of view Bf.1, Bf.2. Preferably, the detection of the event that another object enters the field of view Bf.1, Bf.2 does not trigger a step of changing the maximum irradiance.

[0179] As already explained, the control device 10, when operating in the limited mode, determines the maximum overall irradiance Ee max,ges is the predetermined limit Ee max,req As already explained, in this embodiment, the user or a higher-level control device (not shown) also sets a setting value for each of the lighting units 1, 2, and 3. From this setting value, the control device 10 determines the maximum irradiance Ee that the lighting units 1, 2, and 3 should achieve in the space. max,1,sp ,Ee max,2,sp The control device 10 calculates the maximum irradiance Ee in the space of the lighting units 1, 2, and 3. max,1,sp ,Ee max,2,sp From this, the maximum irradiance Ee of this lighting unit 1, 2, 3 on the surface Ob max,1 ,Ee max,2 and what maximum overall irradiance Ee the lighting device 100 will achieve on the illuminated surface Ob as a result of this setting. max,ges How can we achieve this?

[0180] Expected maximum irradiance Ee max,ges The estimated Ee for max,ges,est is a given upper limit Ee max,reqIn this case, the control device 10 automatically reduces the illuminance and thus the irradiance of at least one lighting unit 1, 2, 3, and after this reduction, the illuminance and thus the irradiance do not exceed a predetermined upper limit Ee max,req In one implementation, the control device 10 reduces the maximum illuminance to be achieved of all lighting units 1, 2, 3 by the same factor, for example the factor Ee max,ges,est / Ee max,req If the illuminance resulting from the set value or the automatic reduction is greater than the upper limit Ee max,req In the case where compliance with the above requirement is achieved, the control device 10 drives and controls the light sources of the lighting units 1, 2, 3 so that the lighting units 1, 2, 3 that are driven and controlled achieve the desired maximum illuminance.

[0181] During operation of the lighting device 100, the user may increase the setting value x (x=1, 2, 3) for a lighting unit. The control device 10 determines whether the increased setting value is still within the predetermined upper limit Ee max,req Maximum overall irradiance Ee max,ges The increased setting value of lighting unit x is automatically checked to see if it exceeds a predetermined limit Ee max,req The estimated maximum irradiance Ee max,ges,est In the case where the lighting unit y (y#x) is in a state where the lighting unit y ... max,req will continue to be observed. [Explanation of symbols]

[0182] 1. A first lighting unit for generating a light field Lf1, including a support 5.1, light sources 1.1, 1.2, ..., and a camera 4.1. 1.1, 1.2, ... light sources of the first lighting unit 1 mounted on the support 5.1 2. A second lighting unit for generating a light field Lf2, which includes a support 5.2, light sources 2.1, 2.2, and a distance sensor 6.2 or a camera 4.2. 2.1, 2.2, ... light sources of the second lighting unit 2 mounted on the support 5.2 3. A third lighting unit that generates the light field Lf3 4.1 a first camera having a field of view Bf.1 mounted on the support 5.1 of the first lighting unit 1 4.2 A second camera having a field of view Bf.2, mounted on the support 5.2 of the second lighting unit 2 5.1 Support of the first lighting unit 1 supporting the light sources 1.1, 1.2, ... 5.2 Support of the second lighting unit 2 supporting the light sources 2.1, 2.2, ... 6.2 Distance sensor of the second lighting unit 2, attached to the support 5.2 7.1,…,7.5 Ridges on the illuminated surface Ob 8.1, 8.2 Contact sensors mounted on supports 5.1, 5.2 9 Operation Unit 10: A control device that receives signals from the cameras 4.1 and 4.2 and the distance sensor 6.2, calculates the maximum irradiance of the lighting device 100, and performs signal processing to drive and control the light sources 1.1, 1.2, ..., 2.1, 2.2, ... 100 Lighting device comprising two lighting units 1 and 2 and optionally a third lighting unit 3 Bf.1 Camera 4.1 Field of View Bf.2 Camera 4.2 Field of View Dist1 is the distance between the first lighting unit 1 and the illuminated surface Ob measured by the camera 4.1 dist2: the distance between the second lighting unit 2 and the illuminated surface Ob, measured by the distance sensor 6.2 or the camera 4.2 Ee Maximum irradiance ("irradiance") Ee max,1 Maximum irradiance of lighting unit 1 on surface Ob Ee max,1,spMaximum irradiance in the space of lighting unit 1 Ee max,2 Maximum irradiance of lighting unit 2 on surface Ob Ee max,2,sp Maximum irradiance in the space of lighting unit 2 Ee max,ges the maximum overall irradiance of the lighting device 100 on the surface Ob resulting from the superposition of the light fields Lf1, Lf2, Lf3 of the three lighting units 1, 2, 3 on the surface Ob Ee max,ges,est Maximum overall irradiance Ee max,ges Estimated value of Ee max,req Maximum overall irradiance Ee max,ges A predetermined upper limit of Lb 1.1 ,Lb 1.2 ,… Light rays emitted by light sources 1.1, 1.2,… Lb 2.1 ,Lb 2.2 ,… Light rays emitted by light sources 2.1, 2.2,… Lf1: the elliptical light field generated by the first lighting unit 1 on the surface Ob Lf 1.1 ,Lf 1.2 ,… Light field generated by light sources 1.1, 1.2,… on surface Ob Lf2: the elliptical light field generated by the second lighting unit 2 on the surface Ob Lf 2.1 ,Lf 2.2 ,… Light field generated by light sources 1.1, 1.2,… on surface Ob Lf3: a circular light field generated by the third lighting unit 3 on the surface Ob MA.1 Optical central axis and geometrical symmetry axis of the first lighting unit 1 MA.2 Optical center axis and geometrical symmetry axis of the second lighting unit 2 Ob: the surface of the object (operating table) Obj facing the illumination device 100 and thus illuminated Obj the illuminated object (operating table) having an illuminated surface Ob S.1 Intersection of the central axis MA.1 and the illuminated surface Ob S.2 Intersection of the central axis MA.2 and the illuminated surface Ob Ueb: The overlap area between two light fields Lf1 and Lf2 on the illuminated surface Ob.

Claims

1. An illumination device (100) for illuminating a surface (Ob) of an object (Obj), the illumination device (100) comprising: at least two lighting units (1, 2, 3); A control device (10) for performing signal processing; Including, Each lighting unit (1, 2, 3) has a maximum irradiance (Ee ｍａｘ，１ , Ee ｍａｘ，２ ) configured to illuminate said surface (Ob), The lighting device (100) illuminates the surface (Ob) with a maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) and is configured to illuminate The maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is the maximum irradiance (Ee ｍａｘ，１ , Ee ｍａｘ，２ ) and The control device (10) - driving and controlling each lighting unit (1, 2, 3) independently of any other lighting unit or each other lighting unit; This allows the maximum irradiance (Ee ｍａｘ，１ , Ee ｍａｘ，２ ), and is configured to change The lighting device (100) is configured to: ｍａｘ，ｇｅｓ ) or the maximum irradiance (Ee ｍａｘ，１ , Ee ｍａｘ，２ ) and configured to detect user preferences related to The control device (10) further automatically, in response to the detection of the user setting: The maximum overall irradiance (Ee) that the lighting device (100) achieves on the surface (Ob) when the lighting device (100) operates according to the user settings. ｍａｘ，ｇｅｓ ) at least approximately, The predicted maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) to a predetermined upper limit (Ee) of the maximum irradiance on the surface (Ob). ｍａｘ，ｒｅｑ ) compared to The predicted maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is the upper limit (Ee ｍａｘ，ｒｅｑ ), Depending on the detected user settings, at least one lighting unit (1, 2, 3) is driven and controlled as follows: After the driving control, the actual achieved maximum total irradiance (Ee ｍａｘ，ｇｅｓ ) is the upper limit (Ee ｍａｘ，ｒｅｑ ) drive control is performed so that the following occurs: A lighting device (100).

2. Each lighting unit (1, 2, 3) of the lighting device (100) generates a light field (Lf １ , Lf ２ , Lf ３ ), The control device (10) The maximum irradiance (Ee) that the lighting units (1, 2, 3) actually achieve on the surface (Ob) ｍａｘ，１ , Ee ｍａｘ，２ ) is calculated for each lighting unit (1, 2, 3) of the lighting device (100), the light field (Lf) generated by the lighting units (1, 2, 3) on the illuminated surface (Ob); １ , Lf ２ , Lf ３ ) are positioned relative to each other, The maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is calculated by comparing the detected user setting with the determined maximum irradiance (Ee ｍａｘ，１ , Ee ｍａｘ，２ ) and the generated light field (Lf １ , Lf ２ , Lf ３ and the determined positioning of The lighting device (100) of claim 1.

3. The lighting device (100) comprises an imaging system with at least one camera (4.1, 4.2), The control device (10) controls the lighting units (1, 2, 3) during the measurement period. At each time point during the measurement period, In a first alternative, exactly one lighting unit (1, 2, 3) is switched on and the or each other lighting unit is switched off, In a second alternative, exactly one lighting unit (1, 2, 3) is switched off and a specific other lighting unit or each other lighting unit is switched on; The drive control is configured as follows: The imaging system (4.1, 4.2) captures a sequence of images of the illuminated surface (Ob) for each light field (Lf) of each lighting unit (1, 2, 3). １ , Lf ２ , Lf ３ ) is the field of view (Bf) of each at least one camera (4.1, 4.2) of said imaging system. １ , Bf ２ ) and the sequence comprises at least one image of the surface (Ob) for each lighting unit (1, 2, 3), the images being generated while the lighting units (1, 2, 3) are switched on in the first alternative and switched off in the second alternative, The control device (10) By evaluating the sequence of images, it is possible to determine which light field (Lf １ , Lf ２ , Lf ３ ) originates from which lighting unit (1, 2, 3), Using this information, the light field (Lf １ , Lf ２ , Lf ３ ) are positioned relative to each other; The lighting device (100) of claim 2.

4. The lighting device (100) is configured to set the maximum irradiance (Ee ｍａｘ，１ ) and configured to detect user preferences related to The control device (10) is configured to drive and control the first lighting unit (1) in such a way that, in response to the drive control, the first lighting unit (1) provides a maximum irradiance (Ee) on the surface (Ob) according to the user setting. ｍａｘ，１ ) and The control device (10) further comprises: The maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) and The predicted maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is the upper limit (Ee ｍａｘ，ｒｅｑ ), A specific second lighting unit (2, 3) or at least one second lighting unit (2, 3) of the lighting device (100), which is different from the first lighting unit (1), is driven and controlled as follows: A specific or each driven second lighting unit (2, 3) produces a maximum irradiance (Ee) on the surface (Ob) that is lower than before the driving control. ｍａｘ，２ ) and configured to control the drive to achieve This allows the maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is the upper limit (Ee ｍａｘ，ｒｅｑ ) becomes: The lighting device (100) according to any one of claims 1 to 3.

5. the control device (10) is configured to determine a lighting unit subset; the lighting unit subset comprises at least one lighting unit (1, 2) of the lighting device (100), and at least one further lighting unit (3) of the lighting device (100) does not belong to the lighting unit subset, The control device (10) further comprises: - each of the maximum irradiances (Ee ｍａｘ，１ , Ee ｍａｘ，２ ) and Specific required maximum irradiance (Ee ｍａｘ，１ , Ee ｍａｘ，２ ) or each determined maximum irradiance (Ee ｍａｘ，１ , Ee ｍａｘ，２ ) to the maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) in the prediction, The lighting device (100) according to any one of claims 1 to 4.

6. The lighting device (100) is configured to detect user settings; The detected user settings include: the lighting unit subset, or a particular lighting unit (3) or each lighting unit (3) of the lighting device (100) that does not belong to the lighting unit subset; Identify the the control device (10) is configured to determine the lighting unit subset using the detected user settings. The lighting device (100) of claim 5.

7. Each lighting unit generates a light field (Lf １ , Lf ２ , Lf ３ ) on the surface, The control device (10) the light field (Lf) achieved by the lighting units (1, 2, 3) on the illuminated surface (Ob); １ , Lf ２ , Lf ３ ) are positioned relative to each other, The lighting unit subset is the light fields of the lighting units (1, 2) of the lighting unit subset overlap; the light field of a particular lighting unit (3) of the lighting device (100) that does not belong to the lighting unit subset or of each lighting unit (3) that does not belong to the lighting unit subset does not overlap with the light field of a lighting unit (1, 2) of the lighting unit subset; It is asked to be, is configured to be, 7. The lighting device (100) of claim 5 or claim 6.

8. The control device (10) is configured to detect an event that changes irradiance; The event that changes the irradiance is the maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ), or at least cause a change in the maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is suitable for changing The control device (10) further comprises: In response to said detection of said event that changes irradiance, The maximum overall irradiance (Ee) that the lighting device (100) actually achieves on the surface (Ob) ｍａｘ，ｇｅｓ ) and The determined actual achieved total irradiance (Ee ｍａｘ，ｇｅｓ ) is the upper limit (Ee ｍａｘ，ｒｅｑ ), At least one lighting unit (1, 2, 3) is driven and controlled as follows: After the driving control, the maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is the upper limit (Ee ｍａｘ，ｒｅｑ ) drive control is performed so that the following occurs: The lighting device (100) according to any one of claims 1 to 7.

9. at least one lighting unit (1, 2) is connected to said distance sensor (4.1, 4.2, 6.2) such that the position and orientation of said distance sensor (4.1, 4.2, 6.2) cannot be changed relative to said lighting unit (1, 2); The distance sensors (4.1, 4.2, 6.2) measure the distance (dist) between the connected lighting units (1, 2) and the illuminated surface (Ob) in a contactless manner. １ , dist ２ ) is configured to measure a measure of The control device (10) may determine the measured distance (dist) as a specific event that changes irradiance or a non-specific event that changes irradiance. １ , dist ２ ) change in the The lighting device (100) of claim 8.

10. the lighting units include contact sensors (8.1, 8.2), the contact sensors (8.1, 8.2) being configured to detect contact with the lighting units (1, 2, 3); the control device (10) is configured to use a touch of the lighting unit (1, 2, 3) detected by the contact sensor (8.1, 8.2) as a specific event for changing irradiance or a non-specific event for changing irradiance.

10. The lighting device (100) of claim 8 or claim 9.

11. The lighting device (100) is configured to be able to activate and deactivate a restricted mode; The control device (10) When the limit mode is activated, the lighting device (100) ｍａｘ，ｇｅｓ ) and If the maximum overall irradiance is greater than the upper limit, the actual achieved maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is the upper limit (Ee ｍａｘ，ｒｅｑ ) becomes: When the limit mode is deactivated, the upper limit (Ee ｍａｘ，ｒｅｑ ) is configured to allow for an excess of The lighting device (100) according to any one of claims 1 to 10.

12. 1. A lighting method for illuminating a surface (Ob) of an object (Obj) using a lighting device (100) comprising at least two lighting units (1, 2, 3) for illuminating said surface (Ob), said method comprising the steps of: Each lighting unit (1, 2, 3) has a maximum irradiance (Ee ｍａｘ，１ , Ee ｍａｘ，２ illuminating said surface (Ob) with The maximum irradiance (Ee ｍａｘ，１ , Ee ｍａｘ，２ ) is the maximum irradiance (Ee) of a particular separate lighting unit (2, 3, 1) or of each separate lighting unit (2, 3, 1). ｍａｘ，２ , Ee ｍａｘ，１ ) and can be changed independently of The lighting device (100) illuminates the surface (Ob) with a maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) illuminating the object with The maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is the maximum irradiance (Ee ｍａｘ，１ , Ee ｍａｘ，２ ) and At least once, the maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) or a user setting associated with each of the maximum irradiances (Ee ｍａｘ，１ , Ee ｍａｘ，２ ) detecting Said detection of said user settings triggers the following steps, which are performed automatically: The maximum overall irradiance (Ee) that the lighting device (100) achieves on the surface (Ob) when the lighting device (100) operates according to the user settings. ｍａｘ，ｇｅｓ ) at least approximately predicting The predicted maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) to a predetermined upper limit (Ee) of the maximum irradiance on the surface (Ob). ｍａｘ，ｒｅｑ ) and comparing it with The predicted maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is the upper limit (Ee ｍａｘ，ｒｅｑ ), and controlling at least one lighting unit (1, 2, 3) depending on the detected user settings as follows: After the driving control, the maximum overall irradiance (Ee) of the lighting device (100) actually achieved on the surface (Ob) ｍａｘ，ｇｅｓ ) is the upper limit (Ee ｍａｘ，ｒｅｑ ) a step of controlling the drive so that: triggering, lighting method.

13. At least once, the maximum irradiance (Ee ｍａｘ，１ ) and find user settings related to The maximum overall irradiance (Ee ｍａｘ，ｇｅｓ The step of predicting the maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) predicting the The step of driving and controlling at least one lighting unit (1, 2, 3) comprises: - driving and controlling the first lighting unit (1) as follows, wherein in response to the driving control, the first lighting unit (1) provides a maximum irradiance (Ee) on the surface (Ob) according to the user setting. ｍａｘ，１ and controlling the driving of the drive shaft to achieve the The predicted maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is the upper limit (Ee ｍａｘ，ｒｅｑ ), A step of driving and controlling a specific second lighting unit (2, 3) or at least one second lighting unit (2, 3) of the lighting device (100) different from the first lighting unit (1), controlling the second lighting unit (2, 3) to be driven so that the or each second lighting unit (2, 3) achieves a lower maximum irradiance on said surface (Ob) than before said controlling. Including, This allows the actually achieved maximum overall irradiance (Ee ｍａｘ，ｇｅｓ ) is the upper limit (Ee ｍａｘ，ｒｅｑ ) becomes:

13. The illumination method according to claim 12.

Images