Light-emitting diode array having adjustable color temperature and simultaneously constant color reproduction
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- OPTICAL DESIGN UNIT GMBH
- Filing Date
- 2024-07-11
- Publication Date
- 2026-05-20
AI Technical Summary
Existing lighting devices for surgical operations face challenges in maintaining constant color rendering quality across various color temperatures, particularly with lower R9 and R13 values, when using combinations of warm white, cool white, and colored LEDs, which complicates color temperature adjustment and increases costs due to the need for high-quality LEDs.
A lighting device comprising a warm white light source, a cold white light source, and a light source unit, controlled by a unit that adjusts light intensities to produce a mixed light with almost constant color rendering quality indices (Ra, R9, and R13) across a range of color temperatures, using lower-quality LEDs to reduce costs and simplify the structure.
The solution achieves consistent color rendering quality across multiple color temperatures with reduced costs by using lower-quality LEDs, ensuring reliable tissue perception in surgical environments without the need for special high-quality LED selection.
Smart Images
Figure EP2024069640_23012025_PF_FP_ABST
Abstract
Description
[0001] LED arrangement with adjustable color temperature and constant color rendering
[0002] Herein, a device and a method for illuminating a surface, in particular a surgical field, are presented.
[0003] The color rendering of a lighting device is particularly important for performing an operation. The operating field in which a surgical procedure takes place should ideally be illuminated in such a way that a doctor, for example a surgeon, can clearly see the tissue and move safely within the operating field with the surgical instruments. For certain surgical situations, the color temperature must be adjusted. When adjusting the color temperature (Correlated Color Temperature, CCT for short), it is advantageous if parts of a color rendering index, for example the Ra value, R9 value and the R13 value of the Color Rendering Index (RCI), are constant across all set color temperatures, as these parts of the color rendering index of the lighting device determine how the doctor, for example the surgeon, perceives the skin and tissue when the operating field is illuminated with the appropriate lighting.To achieve such a property, arrangements consisting of two light sources, in particular light-emitting diodes (LEDs), which are arranged in a lighting device are known from the prior art. One of the two LEDs emits a warm white light and the other LED a cool white light. The LEDs used for this purpose are designed as so-called medical LEDs and are correspondingly expensive. Although in this case both LEDs have high Ra, R9 and R13 values, lower values, in particular lower R9 values, are achieved in the resulting mixed light. Another possibility known in the prior art is the arrangement of several LEDs, e.g. one warm white, one cool white and one or more colored LEDs. In this case, setting the color temperature is complex and the resulting values are not constant across the said color temperatures to be set.
[0004] There is a need for a lighting device that is as simple as possible and whose color rendering quality is as uniform as possible, in particular at least almost constant, across all adjustable color temperatures.
[0005] For this purpose, a device according to claim 1 and a method according to claim 15 are proposed. According to a first aspect, a device for illuminating a surface, in particular a surgical field, is proposed. The device has a first warm white light source. The warm white light source is designed to emit a first warm white light. The device further has a first cold white light source. The cold white light source is designed to emit a first cold white light. The device for illumination further has a first light source unit. The first light source unit is designed to emit a second light. The device for illumination further has a lighting body. The lighting body is designed to accommodate the light sources (ie, the warm white light source and the cold white light source) and the light source unit and to supply them with energy.The first warm white light source, the first cold white light source, and the first light source unit are each configured to receive control commands from a control unit. The control unit is configured to control at least one light intensity of the first warm white light, the first cold white light, and / or the second light. The first warm white light, the first cold white light, and the second light result in a mixed light at a distance from the device. In other words, the first warm white light, the first cold white light, and the second light form or shape a mixed light at a distance from the device. The mixed light has a mixed color temperature. The mixed light has at least one value for at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value, which is / are at least virtually constant across a plurality of mixed color temperatures.
[0006] The mixed light can have (at least) one value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value, which is / are at least virtually the same across a plurality of mixed color temperatures. The mixed light can have (at least) one value of at least part of the color rendering quality, in particular an R9 and / or R13 value, which is / are at least virtually the same across a plurality of mixed color temperatures. Across a plurality of mixed color temperatures, at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value, can correspond to an average value of 90, 95, 97, 98, 99, or 100. Across a plurality of mixed color temperatures, at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value, can correspond to a mean value of 90, 95, 97, 98, or 99 and can be scattered around this mean value, in particular by ±0.5, ±1, ±2, ±3, ±5, ±10.The mixed light may have (at least) one value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value, which is greater than (equal to) 90, 95, 97, 98 or 99 over a plurality of mixed color temperatures.
[0007] Color rendering quality can be understood as any color rendering index, e.g., CRI (Color Rendering Index) or CFI (Color Fidelity Index or Rf). The value of color rendering quality can be understood as a key figure of the corresponding color rendering index, e.g., CRI 95 in the case of CRI as color rendering quality. Components used to calculate the color rendering index can be understood as components, e.g., R9 value or R15 value in the case of CRI; or RfCES49 in the case of CFI; or corresponding other components of indices known to those skilled in the art of CRI or CFI.
[0008] The second light is referred to as such to distinguish it from the first warm white light and the first cool white light. Likewise, the second light may be referred to as the first light or simply as light, without altering the content and / or teaching described herein. Likewise, the mixed light may be referred to herein as mixed light or blended light.
[0009] The first warm white light and the first cold white light can each have a color rendering quality value, in particular CRI / CFI 90, 95, or 100. The values of the first warm white light and the first cold warm light can, in particular, be approximately the same. The second light can have a color rendering quality value that differs from the values of the first warm white light and the first cold white light. The color rendering quality value of the second light can be reduced / decreased compared to the color rendering quality of the first warm white light and / or the first cold white light, for example, by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50, in particular can be deliberately selected to be reduced / decreased (by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50). The color rendering quality value of the second light can be less than (equal to) 85, 80, 75, or 70.
[0010] This has the advantage of a simple structure and, consequently, reduced costs, since the device can also use light sources that have (or may have) lower quality, i.e., lower CRI values, than complex and / or expensive LEDs (e.g., medical LEDs). As a result, the color rendering quality (CRI values and / or individual indices) of the mixed light is not limited or impaired. In addition, constant R9 or R13 values are achieved, even though additional LEDs are used that themselves have a lower R9 or R13 value compared to, for example, medical LEDs. The cost savings arise, among other things, from the fact that special selection of high-quality LEDs is no longer necessary, since low-quality LEDs can be used that do not require prior special selection.
[0011] The device may comprise an optical system. The optical system may be configured to receive the warm white light, the cool white light, and the second light, mix them, and emit them as a mixed light. The optical system may be configured as a first, second, and / or third optical system, one of which is assigned to each of the warm white light source, the cool white light source, and / or the light source unit.
[0012] The light source unit can be configured as a second warm white light source or as a second cool white light source, or can have a second warm white light source or a second cool white light source. The light source unit can be configured as a first neutral white light source or can have a first neutral white light source. The second warm white light source can be configured to emit a second warm white light. The second cool white light source can be configured to emit a second cool white light. The first neutral white light source can be configured to emit a first neutral white light.
[0013] The second light may have a value of at least a part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), which differs from values of the part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the first warm white light and / or the first cold white light.
[0014] The second light can have a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), which can be reduced / reduced from the values of the part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the first warm white light and / or the first cold white light, in particular by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50, in particular can be deliberately selected to be reduced / reduced (by a value of 5, 10, or 15, 20, 25, 30, 35, 40, 45 or 50).
[0015] The second warm white light, the second cold white light and / or the first neutral white light can have a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), which differs from values of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the first warm white light and / or the first cold white light.
[0016] The second warm white light, the second cold white light and / or the first neutral white light can have a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), which can be reduced / reduced from / compared to values of the at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the first warm white light and / or the first cold white light, in particular by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50, in particular can be deliberately selected to be reduced / reduced (by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50). The value of a part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the second warm white light, the second cold white light, and / or the first neutral white light, can be less than (equal to) 85, 80, 75, or 70.
[0017] The light source unit can be configured as a second warm white light source and as a second cool white light source. The second warm white light source can be configured to emit a second warm white light. The second cool white light source can be configured to emit a second cool white light.
[0018] The second warm white light can have a color rendering quality value, in particular CRI / CFI 90, 95, or 100, that is at least nearly identical to a color rendering quality value, in particular CRI / CFI 90, 95, or 100, of the second cold white light. A color rendering quality value, in particular CRI / CFI 90, 95, or 100, of the second warm white / cold white light can differ from a color rendering quality value, in particular CRI / CFI 90, 95, or 100, of the first warm white / cold white light. A value of the color rendering quality, in particular CRI / CFI 90, 95 or 100, of the second warm white / cold white light can be reduced / reduced compared to a value of the color rendering quality, in particular CRI / CFI 90, 95 or 100, of the first warm white / cold white light, in particular by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50, in particular deliberately selected (by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50).The color rendering quality value of the second warm white / cool white light can be less than (equal to) 85, 80, 75, or 70.
[0019] The first warm white light can have a color rendering quality value, in particular CRI / CFI 90, 95 or 100, which at least approximately corresponds to / equals a color rendering quality value, in particular CRI / CFI 90, 95 or 100, of the first cold white light. The second warm white light can have a color rendering quality value, in particular CRI / CFI 90, 95 or 100, which at least approximately corresponds to / equals a color rendering quality value, in particular CRI / CFI 90, 95 or 100, of the second cold white light. The second warm white / cold white light can have a color rendering quality value, in particular CRI / CFI 90, 95 or 100, which differs from the color rendering quality value, in particular CRI / CFI 90, 95 or 100, of the first warm white light.The second warm white / cold white light can have a color rendering quality value, in particular CRI / CFI 90, 95, or 100, which can be reduced / reduced compared to the color rendering quality value, in particular CRI / CFI 90, 95, or 100, of the first warm white light, in particular by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50, in particular can be deliberately selected to be reduced / reduced (by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50). The color rendering quality value of the second warm white / cold white light can be less than (equal to) 85, 80, 75, or 70.
[0020] The first warm white light, the first cold white light, and the second cold white light can have at least nearly identical color rendering quality values, in particular CRI / CFI 90, 95, or 100. The second warm white light can have a color rendering quality value, in particular CRI / CFI 90, 95, or 100, that differs from the at least nearly identical values. The second warm white light can have a color rendering quality value, in particular CRI / CFI 90, 95 or 100, which can be reduced / reduced compared to the at least almost identical values, in particular by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50, in particular can be deliberately selected to be reduced / reduced (by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50).
[0021] The first warm white light, the first cold white light, and the second cold white light can have at least virtually identical color rendering quality values, in particular CRI / CFI 90, 95, or 100. The second cold white light can have a color rendering quality value, in particular CRI / CFI 90, 95, or 100, that differs from the at least virtually identical color rendering quality values. The second cold white light can have a color rendering quality value, in particular CRI / CFI 90, 95 or 100, which can be reduced / reduced compared to the at least almost identical color rendering quality values, in particular by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50, in particular can be deliberately selected to be reduced / reduced (by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50).
[0022] The second warm white light can have a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), which at least approximately corresponds to / equals a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the second cold white light. The second warm white / cold white light can have a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), which differs from a value of the part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the first warm white light or the first cold white light.The second warm white / cold white light can have a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), which can be reduced / reduced compared to a value of at least part of the color rendering quality of the first warm white light or the first cold white light, in particular by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50, in particular can be deliberately selected to be reduced / reduced (by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50).
[0023] The first warm white light, the first cool white light, and the second cool white light can have at least nearly identical values for at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s). The second warm white light can have a value for at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), that differs from the at least nearly identical values (of the first warm white light, the first cool white light, and the second cool white light).The second warm white light can have a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), which can be reduced / reduced compared to the at least almost identical values (of the first warm white light, the first cold white light and the second cold white light), in particular by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50, in particular can be deliberately selected to be reduced / reduced (by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50). The value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the second warm white / cold white light can be less than (equal to) 85, 80, 75, or 70.The second warm white light can have a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), that at least nearly corresponds to a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the second cold white light. A value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the second warm white / cold white light can differ from a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the first warm white light or the first cold white light.A value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the second warm white / cold white light can be reduced / reduced compared to a value of at least part of the color rendering quality, in particular an Ra, R9, and / or R13 value(s), of the first warm white light or the first cold white light, in particular by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50, in particular deliberately selected to be reduced / reduced (by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50).
[0024] The control unit can be designed to control (at least) a light intensity of the first warm white light, the first cold white light and / or the second light, in particular the second warm white light, the second cold white light or the first neutral white light, depending on one another and / or in compliance with at least one boundary condition.
[0025] The control unit can be designed to control (at least) a light intensity of the first and / or the second warm white light and / or cold white light depending on one another and / or in compliance with at least one boundary condition.
[0026] According to a second aspect, a method for illuminating a surface, in particular a surgical field, is proposed. The method comprises providing a first warm white light source configured to emit a first warm white light. The method comprises providing a first cold white light source configured to emit a first cold white light. The method comprises providing a first light source unit configured to emit a second light. The first warm white light source, the first cold white light source, and the first light source unit are each configured to receive control commands from a control unit. The method comprises providing the control unit configured to control light intensities of the first warm white light, the first cold white light, and / or the second light.The method comprises mixing the first warm white light, the first cool white light, and the second light to form a mixed light having a mixed color temperature. The method comprises controlling at least one of the light intensities of the first cool white light, the first warm white light, and / or the second light such that the mixed light has at least one value over at least part of the color rendering quality that is at least nearly constant across a plurality of mixed color temperatures.
[0027] The first warm white light and the first cool white light can have at least almost identical values of a color rendering quality, in particular CRI / CFI 90, 95 or 100. The second light can have a value of the color rendering quality, in particular CRI / CFI 90, 95 or 100, which differs from the at least almost identical values. The second light can have a value of the color rendering quality, in particular CRI / CFI 90, 95 or 100, which differs from / compared to the at least almost identical values, in particular by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50, in particular can be deliberately selected to be reduced / reduced (by a value of 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50). The color rendering quality value of the second light can be less than (equal to) 85, 80, 75, or 70.
[0028] The control of the light intensity of the first cold white light, the first warm white light and / or the second light can be carried out depending on one another and / or in compliance with at least one boundary condition.
[0029] Further features, characteristics, advantages and possible modifications will become clear to a person skilled in the art from the following descriptions, which refer to the accompanying drawings.
[0030] Fig.l shows an example of a lighting device for illuminating a surface.
[0031] Fig.2 shows an example of a lighting device in which the light source unit is designed as a neutral white light source.
[0032] Fig.3 shows an example of a lighting device in which the light source unit is designed as a second warm white light source and as a second cold white light source.
[0033] Fig.4 shows a method for lighting with controllable color temperature.
[0034] Fig. 5 shows examples of spectra from different LEDs at different CRIs. Fig. 6 shows the color rendering indexes for a mixture of four LEDs.
[0035] Fig.7 shows the color rendering quality indicators for the mixture of 3 LEDs.
[0036] Fig.8 shows an example of an arrangement variant of 4 LEDs.
[0037] Fig.9 shows an example of an arrangement variant of 4 LEDs.
[0038] Fig.10 shows an example of an arrangement variant of 4 LEDs.
[0039] Figure 1 shows an example of a lighting device 1 for illuminating a surface, in particular a surgical field. It shows the view of the warm white light source 10, the cool white light source 20, and the light source unit 30, which are mounted on a lighting fixture 50 and supplied with power via the latter.
[0040] The warm white light source 10 emits a warm white light, the cold white light source 20 emits a cold white light and the light source unit 30 emits a second light.
[0041] In addition to the light sources 10, 20 and the light source unit 30, a control unit 40 is located on the lighting fixture 50. Alternatively, the control unit can be positioned decentrally, for example, separately or outside the lighting fixture 5. The control unit 40 is connected to the light sources 10, 20 and the light source unit 30 via a line, along which control commands SB are transmitted. The light intensity of each light source 10, 20 and the light source unit 40 is controllable. The control unit 40 controls the light intensities of the light sources 10, 20 and the light source unit 40.
[0042] At a distance from the device 1, a mixed light results from the warm white light of the warm white light source 10, the cold white light of the cold white light source 20 and the second light of the light source unit 30. The mixed light can be adjusted in its color temperature by the control unit 40 controlling the light intensity of at least one warm white light source 10, cold white light source 20 and / or the light source unit 30.
[0043] How the control unit 40 controls the light sources 10, 20 or the light source unit 30 using control commands SB depends on a previously determined optimization function, which is calculated by a person skilled in the art in compliance with at least one boundary condition. For example, the optimization function can be calculated such that a constant value of a portion of the color rendering quality is to be present for a desired color temperature of the mixed light, e.g., a specific R9 value for the desired color temperature of the mixed light for given color quality values (e.g., CRI 90) of the light sources 10, 20 or the light source unit 30 used. The optimization function then contains the corresponding (one or more) parameters to be set in order to obtain a mixed light with the previously calculated / specified color quality values. These parameters can be mixing ratios or light intensity values of the light sources 10, 20 and the light source unit 40.To ensure that a component of a color rendering quality has the same value for a further desired color temperature of the mixed light, an optimization function is recalculated. The recalculated optimization function was calculated under the constraint that a component of a color rendering quality of the mixed light of the further desired color temperature is equal to the component of the color rendering quality of the mixed light of the desired color temperature, for example, the same R9 values for different color temperatures.
[0044] Figure 2 shows an example of a lighting device 1 for illuminating a surface, in particular a surgical field. It shows a view of a warm white light source 10, a cool white light source 20, and a neutral white light source 32, which are mounted on a lighting fixture 50 and supplied with power via the latter.
[0045] The warm white light source 10 emits a warm white light, the cool white light source 20 emits a cool white light and the neutral white light source 32 emits a neutral white light.
[0046] In addition to the light sources 10, 20, 32, a control unit 40 is located on the lighting fixture 50. The control unit 40 is connected to the light sources 10, 20, 32 via one or more lines and transmits control commands. The light intensity(ies) of each light source 10, 20, 32 is / are controllable. The control unit 40 controls the light intensity of the light sources 10, 20, 32.
[0047] At a distance from the device, a mixed light results from the warm white light of the warm white light source 10, the cool white light of the cool white light source 20, and the neutral white light of the neutral white light source 32. The color temperature of the mixed light can be adjusted by the control unit 40 controlling / changing the light intensities of at least one light source 10, 20, 32. How the control unit 40 controls the light sources 10, 20, 32 using control commands SB depends on a previously determined optimization function, which is calculated by a person skilled in the art subject to at least one boundary condition. For example, the optimization function can be calculated such that a constant value of a part of the color rendering quality should be present for a desired color temperature of the mixed light, e.g., a constant R9 value for the desired color temperature of the mixed light for given values of a color quality of the light sources 10, 20, 32 used (e.g.CRI 90, CRI 90, and CRI 85). The optimization function then contains the corresponding parameters to be set in order to obtain a mixed light with the previously specified values of a color quality for the desired mixed light color temperatures. These parameters can be mixing ratios or light intensity values of the light sources 10, 20, and light source unit 40. To ensure that an identical value of a part of a color rendering quality is available for a further desired color temperature of the mixed light, an optimization function is calculated again. The recalculated optimization function was calculated under the boundary condition that a value of a part of a color rendering quality of the mixed light of the further desired color temperature is equal to the value of a part of the color rendering quality of the mixed light of the desired color temperature, for example, the same R9 values for different color temperatures.
[0048] In the example shown, the warm white light and the cool white light both have the same color rendering quality values. In the example shown, the warm white light and the cool white light therefore both have a CRI of 95. In the example shown, the neutral white light has a color rendering quality value that is lower than the color rendering quality value of the warm white\cool white light. The neutral white light has a CRI of 90. The given CRI values and the boundary conditions are made available to the optimization function to be calculated, and the optimization function is then calculated. This specifies which light intensity of the cool, warm, and / or neutral white light must be controlled and how to result in a mixed light color temperature that complies with the specified boundary conditions, e.g., a constant R9 and R13 value for one or more color temperatures of the mixed light.
[0049] Figure 3 shows an example of a lighting device 1 for illuminating a surface, in particular a surgical field. It shows a view of a first warm white light source 10, a first cool white light source 20, a second warm white light source 36, and a second cool white light source 34, which are mounted on a lighting fixture 50 and supplied with power via the latter.
[0050] The first warm white light source 10 emits a first warm white light, the first cold white light source 20 emits a first cold white light, the second warm white light source 36 emits a second warm white light and the second cold white light source 34 emits a second cold white light.
[0051] In addition to the light sources 10, 20, 34, 36, a control unit 40 is located on the lighting fixture 50. The control unit 40 is connected to the light sources 10, 20, 34, 36 via one or more lines and transmits the control commands SB. The light intensity(ies) of each light source 10, 20, 34, 36 is / are controllable. The control unit 40 controls the light intensities of the light sources 10, 20, 34, 36.
[0052] At a distance from the device 1, a mixed light is produced from the first and second warm white lights and the first and second cold white lights. The color temperature of the mixed light can be adjusted by the control unit 40 controlling the light intensity of at least one light source 10, 20, 34, 36.
[0053] How the control unit 40 controls the light sources 10, 20, 34, 36 using control commands SB depends on a previously determined optimization function, which is calculated by a person skilled in the art in compliance with at least one boundary condition. For example, the optimization function can be calculated such that a specific value of a portion of the color rendering quality should be present for a desired color temperature of the mixed light, e.g., a specific R13 value for the desired color temperature(s) of the mixed light for given color quality values of the light sources 10, 20, 34, 36 used (e.g., 10, CIR 95; 20, CRI 95; 34, CRI 90; 36, CRI 90). The optimization function then contains the corresponding parameters to be set in order to obtain a mixed light with the previously specified color quality values.
[0054] In the example shown, the first warm white light and the first cool white light both have the same color rendering quality values. In the example shown, the first warm white light and the first cool white light both have a CRI of 95. In the example shown, the second warm white light and the second cool white light have a color rendering quality value that is reduced compared to the color rendering quality value of the first warm white / cool white light. The color rendering quality values of the second warm white light and the second cool white light are the same. In the example shown, the second cool white light and the second warm white light have a CRI of 90. In other words, two additional light sources with intentionally reduced CRI values are mounted in addition to the light sources with a high CRI value.
[0055] The given CRI values, spectra of the light sources and / or the boundary conditions are made available to the optimization function to be calculated, and the optimization function is then calculated, which specifies which light intensity of the first cold, warm white light and / or the second cold, warm white light must be controlled and how, so that a mixed light color temperature is obtained that complies with the specified boundary conditions.
[0056] Figure 4 illustrates the illumination method. In a first step S101, a first warm white light source 10 is provided, which is configured to emit a first warm white light. In a second step S102, a first cold white light source 20 is provided, which is configured to emit a first cold white light. In a third step S103, a first light source unit 30 is provided, which is configured to emit a second light. The first warm white light source 10, the first cold white light source 20, and the first light source unit 30 are each configured to receive control commands SB from a control unit 40. In a fourth step S104, the control unit 40 is provided, which is configured to control the at least one light intensity of the first warm white light, the first cold white light, and / or the second light.In a fifth step S105, the first warm white light, the first cool white light, and the second light are mixed to form a mixed light having a mixed color temperature. In a sixth step S106, at least one of the light intensities of the first cool white light, the first warm white light, or the second light is controlled so that the mixed light has at least one value over at least part of a color rendering quality that is (approximately) constant across a plurality of mixed color temperatures.
[0057] Figure 5 shows the spectral density plots of four light source units. Two diagrams are shown in the upper part of Figure 5. The left of the two diagrams shows the SPD plot for a first and a second warm white light. The first warm white light has a CRI of 95 at a color temperature of 2735K, an Ra value of 96, an R9 value of 97, and an R13 value of 98. The second warm white light, on the other hand, has a CRI of 90 at a color temperature of 2699K, an Ra value of 94, an R9 value of 64, and an R13 value of 94. The second warm white light therefore has a color quality value that differs from the color quality value of the first warm white light.
[0058] The two images below the left diagram each show a spectral density plot of the first and second warm white light.
[0059] The left diagram shows the SPD plot for a first cool white light and a second cool white light. The first cool white light has a CRI of 95 at a color temperature of 5611K, an Ra value of 96, an R9 value of 97, and an R13 value of 98. The second cool white light has a CRI of 90 at a color temperature of 5696K, an Ra value of 92, an R9 value of 78, and an R13 value of 93. The second cool white light has a color rendering quality value that differs from the color quality values of the first cool white light and the first warm white light.
[0060] The two lower images below the right diagram each show a spectral density plot of the first and second cold white light.
[0061] Figure 6 shows the values of parts of the color quality of the mixed light when the light from four light sources is mixed into a mixed light. A first cool white light and a first warm white light were used for this purpose; both have the same color quality value. In other words, both have a CRI of 95. A second warm white light and a second cold white light were mixed with these first two warm white / cool white lights. The second cool white light and the second warm white light have the same color quality value. In other words, the second cool white light and the second warm white light have a CRI of 90. The color quality value of the first warm white / cool white light differs from the color quality value of the second warm white / cool white light. Appropriate control using a control unit results in a nearly constant value for part of the color rendering quality.For example, the R9 value is almost constant across all adjustable color temperatures of the mixed light.
[0062] Figure 7 shows values of parts of the color quality of the mixed light when light from three light sources is mixed to create a mixed light. A first cool white light and a first warm white light were used for this purpose; both have the same color quality value. In other words, both have a CRI of 95. A second warm white light was mixed with these first two warm white / cool white lights. The color quality value of the second warm white light differs from the color quality values of the first cool white light and the first warm white light. In other words, the second warm white light has a CRI of 90. The color quality value of the first warm white / cool white light differs from the color quality value of the second warm white light. By appropriately controlling the light using a control unit, a nearly constant value of a part of the color rendering quality is achieved across all adjustable color temperatures of the mixed light.For example, the R9 value is almost constant across all adjustable color temperatures of the mixed light.
[0063] Figure 8 shows a variant arrangement in which a first warm white light source 10, a first cool white light source 20, a second warm white light source 36, and a second cool white light source 34 are arranged on a lighting fixture 50. Each light source 10, 20, 34, 36 is assigned an optic 60, in particular arranged above the corresponding light source, which receives the light from the respective light source 10, 20, 36, 34 and projects / emits it onto a surface, e.g., a surgical field.
[0064] Figure 9 shows a variant arrangement in which a first warm white light source 10, a first cool white light source 20, a second warm white light source 36, and a second cool white light source 34 are arranged on a lighting fixture 50. A first optical system is assigned to the first warm white light source and the first cool white light source, in particular arranged above the first warm white light source and the first cool white light source. A second optical system 60 is assigned to the second warm white light source and the second cool white light source, in particular arranged above the second warm white light source and the second cool white light source. Each optical system receives the light from the corresponding light sources and emits it onto a surface, e.g., a surgical field.In the variant shown, the light from the first warm white light source and the first cool white light source are mixed in the first optics, and the light from the second warm white light source and the second cool white light source are mixed in the second optics. The mixed light is then produced at a distance from device 1 from the mixed light from the first optics and the mixed light from the second optics.
[0065] Figure 10 shows a variant arrangement in which a first warm white light source 10, a first cool white light source 20, a second warm white light source 36, and a second cool white light source 34 are arranged on a lighting fixture 50. All light sources 10, 20, 36, 34 are assigned an optical system 60, which mixes the light from the light sources 10, 20, 36, 34 and projects it onto a surface, e.g., onto a surgical field. This arrangement enables simple mixing in the optical system, since the light sources are arranged on two intersecting axes, at the same distance from the intersection point.
Claims
Claims 1. A device (1) for illuminating a surface, in particular an operating field, comprising: - a first warm white light source (10) which is designed to emit a first warm white light, - a first cold white light source (20) which is designed to emit a first cold white light, - a first light source unit (30) designed to emit a second light, - a lighting fixture (50) configured to accommodate and supply energy to the first warm white light source (10), the first cold white light source (20), and the first light source unit (30), wherein the first warm white light source (10), the first cold white light source (20), and the first light source unit (30) are each configured to receive control commands (SB) from a control unit (40), wherein the control unit (40) is configured to control a light intensity of the first warm white light (10), the first cold white light (20), and / or the second light (30), wherein the first warm white light, the first cold white light, and the second light mix at a distance from the device (1) to form a mixed light having a mixed color temperature, wherein the mixed light has at least one value of at least part of a color rendering quality that is at least virtually constant across a plurality of mixed color temperatures.
2. The device (1) according to claim 1, wherein the first warm white light and the first cold white light have at least almost equal values of a color rendering quality and the second light has a value of the color rendering quality that differs from the at least almost equal values, in particular is reduced compared to these.
3. The device according to claim 1 or 2, comprising an optic configured to receive the warm white light, the cool white light and the second light, to mix them and to emit them as a mixed light.
4. The device (1) according to one of claims 1 to 3, wherein the light source unit (30) is designed as a second warm white light, second cold white light or first neutral white light source (32), wherein the second warm white light source is designed to emit a second warm white light, the second cold white light source is designed to emit a second cold white light or the first neutral white light source (32) is designed to emit a first neutral white light.
5. The device (1) according to one of claims 1 to 4, wherein the second light or the second warm white light, the second cold white light or the first neutral white light has a value of at least a part of the color rendering quality that differs from values of the at least a part of the color rendering quality of the first warm white light and / or the first cold white light, in particular is reduced compared to these.
6. The device (1) according to one of claims 1 to 3, wherein the light source unit is designed as a second warm white light source (36) and as a second cold white light source (34), wherein the second warm white light source (36) is designed to emit a second warm white light and the second cold white light source (34) is designed to emit a second cold white light.
7. The device (1) according to claim 6, wherein the second warm white light has a color rendering quality value that is at least nearly equal to a color rendering quality value of the second cold white light and differs from, and is in particular reduced compared to, a color rendering quality value of the first warm white light and / or the first cold white light.
8. The device (1) according to claim 6 or 7, wherein the first warm white light, the first cold white light and the second cold white light have at least almost equal values of a color rendering quality and the second warm white light has a value of the color rendering quality which differs from the at least differs from almost identical values, in particular is reduced compared to these.
9. The device (1) according to one of claims 6 to 8, wherein the first warm white light, the first cold white light and the second cold white light have at least almost identical values of a color rendering quality and the second cold white light has a value of the color rendering quality that differs from the at least almost identical values of the color rendering quality, in particular is reduced compared to these.
10. The device (1) according to one of claims 6 to 9, wherein the second warm white light has a value of a part of the color rendering quality that is at least almost equal to a value of the one part of the color rendering quality of the second cold white light and differs from a value of the at least one part of the color rendering quality of the first warm white light and / or the first cold white light, in particular is reduced compared to these.
11. The device (1) according to one of claims 6 to 10, wherein the first warm white light, the first cold white light and the second cold white light have at least almost equal values of a part of the color rendering quality and the second warm white light has a value of the part of the color rendering quality that differs from the at least almost equal values, in particular is reduced compared to these.
12. The device (1) according to one of claims 6 to 11, wherein the second warm white light has a value of a part of the color rendering quality that is at least almost equal to a value of the part of the color rendering quality of the second cold white light and differs from a value of the at least part of the color rendering quality of the first warm white light or the first cold white light, in particular is reduced compared to these.
13. The device (1) according to one of claims 1 to 5, wherein the control unit (40) is further designed to control at least one light intensity of the first warm white light, the first cold white light and / or the second light, in particular the second warm white light, the second cold white light or the first neutral white light, dependent on one another and / or in compliance with at least one boundary condition.
14. The device (1) according to one of claims 6 to 12, wherein the control unit (40) is further designed to control at least one light intensity of the first and / or the second warm white light and / or cold white light dependent on one another and / or in compliance with at least one boundary condition.
15. A method for illuminating a surface, in particular an operating field, comprising the steps: - providing a first warm white light source (10) configured to emit a first warm white light (S101); - providing a first cold white light source (20) configured to emit a first cold white light (S102); - Providing a first light source unit (30) which is designed to emit a second light (S103), wherein the first warm white light source (10), the first cold white light source (20) and the first light source unit (30) are each designed to receive control commands (SB) from a control unit (40); - providing the control unit (40) which is designed to control light intensities of the first warm white light, the first cold white light and / or the second light (S104); - Mixing the first warm white light, the first cold white light and the second light to form a mixed light having a mixed color temperature (S105); - Controlling at least one light intensity of the light intensities of the first cold white light, the first warm white light or the second light, so that the mixed light has at least one value over at least part of a color rendering quality that is at least almost constant over a plurality of mixed color temperatures (S106).
16. The method according to claim 15, wherein the first warm white light and the first cold white light have at least nearly equal values of a color rendering quality and the second light has a value of the color rendering quality which differs from the at least almost identical values, in particular is reduced compared to these.
17. A method for illumination according to claim 15 or 16, wherein the control of the light intensities of the first cold white light, the first warm white light and / or the second light takes place in dependence on one another and / or in compliance with at least one boundary condition.
18. A method for illumination according to any one of claims 15 to 17, wherein the second light comprises a second warm white light and a second cold white light, wherein the control of the light intensities of the first and / or the second warm white light and / or cold white light takes place in dependence on one another and / or in compliance with at least one boundary condition.