System and method for accurate color positioning of white and saturated colors

Abstract

A method of driving a plurality of LED-based light sources to provide an accurate white point and saturated color points. The method includes receiving or setting a selectable target chromaticity; determining that the selectable target chromaticity is between two vertices of a global common color gamut; defining an inner region within the global common color gamut; calculating a first directed distance between the selectable target chromaticity and a transition boundary of the inner region, and a second directed distance between the selectable target chromaticity and a straight side of the global common color gamut; and modifying the selectable target chromaticity to a modified target chromaticity within a fixture color gamut based at least in part on the calculated first and second directed distances, or generating activation signals for driving the plurality of light sources based on the selectable target chromaticity based at least in part on the calculated first and second directed distances.

Description

TECHNICAL FIELD

[0001] The present disclosure is generally directed to lighting systems and methods that use light emitting diodes (LEDs) for accurate white / soft color points and saturated colors without requiring a user to change settings or reconfigure the lighting fixture. BACKGROUND

[0002] LED lighting products can only produce colors within their own actual color gamut. Due to manufacturing variances inherent in LED technology, no two LEDs are exactly the same. Color variances can be significant, especially between different products and LED manufacturers. Thus, no two LED lights can produce exactly the same color gamut of colors. For example, two LED lights can produce a certain color point that represents white light, but they will produce the color point differently because they have different color gamuts.

[0003] Despite these variances, it is desirable to be able to specify the exact color of light, especially white light. One typical solution to this problem involves limiting all LED products to a small color gamut that is common to all LED products. This is beneficial because it standardizes the way color points are delivered to the products. Using a small common color gamut enables different LED fixtures to accurately locate colors within the small common color gamut. Unfortunately, as the number of LED products in a lighting system increases, the size of the color gamut that is common to all products decreases. The small size of the common color gamut means that the products can only produce white and soft colors, not saturated colors. Thus, while different LED fixtures are able to accurately locate colors within the small common color gamut, they lose the ability to produce saturated colors that are outside of their color gamut. Other solutions sacrifice consistency between LED fixtures for the widest possible color gamut (i.e., the most saturated colors). Switching between providing accurate white points and providing fully saturated colors requires changing settings or reconfiguring the LED lighting fixture.

[0004] Thus, there is a need in the art for LED lighting systems and methods that are configured to provide accurate white points and saturated colors without requiring changing settings or reconfiguring the lighting fixture. The systems and methods described herein also exhibit consistent behavior with respect to DMX values and temperature changes. SUMMARY

[0005] The present disclosure relates to an inventive system and method for controlling one or more LED lighting products to provide accurate white / soft color points and saturated color points without requiring changes to settings or reconfiguration of the lighting device. The system disclosed herein includes at least one lighting product comprising a plurality of light sources, preferably LED-based light sources. The system further includes a controller configured to designate a central portion of an operating gamut as an accurate region for accurate positioning of white / soft colors, and to designate an outer portion of the operating gamut as a saturated region for positioning of saturated colors. The controller is further configured to blend between the central portion and the outer portion based on a user requested color point.

[0006] Generally, in one aspect, a method of driving a plurality of LED-based light sources with a selectable target chromaticity in a color space is provided. The method includes receiving or setting a selectable target chromaticity within a global common gamut of the color space; determining that the selectable target chromaticity is between two adjacent vertices of a first plurality of vertices of the global common gamut; defining an inner region within the global common gamut with a transition boundary; and calculating a first directed distance between the selectable target chromaticity and the transition boundary of the inner region, and a second directed distance between the selectable target chromaticity and a straight edge of the global common gamut between the two adjacent vertices. The method further includes modifying the selectable target chromaticity to a modified target chromaticity within a fixture gamut based at least in part on the calculated first and second directed distances, or generating an activation signal for driving the plurality of LED-based light sources based on the selectable target chromaticity based at least in part on the calculated first and second directed distances.

[0007] In an example embodiment, the method further includes calculating the fixture gamut, wherein the fixture gamut at least partially encloses the global common gamut, and the step of calculating the fixture gamut includes determining or receiving chromaticity data indicative of chromaticity characteristics of light emitted by the plurality of LED-based light sources, wherein the chromaticity characteristics define the fixture gamut.

[0008] In an example embodiment, the fixture gamut completely encloses the global common gamut.

[0009] In an example embodiment, the step of defining the inner region includes defining a global gamut center by calculating an average of chromaticity values of color points at the first plurality of vertices of the global common gamut; extending a line between the global gamut center and each of the first plurality of vertices of the global common gamut; and positioning a second plurality of vertices such that each of the second plurality of vertices intersects one of the lines extending between the global gamut center and each of the first plurality of vertices, and the transition boundary connects the second plurality of vertices.

[0010] In an example embodiment, the step of defining the interior region includes defining a global color gamut center by calculating an average of chroma values of color points at a first plurality of vertices of the global common color gamut; positioning a second plurality of vertices such that each vertex of the second plurality of vertices is between the global color gamut center and respective vertices of the first plurality of vertices; and connecting transition boundaries between the second plurality of vertices; wherein the first and second plurality of vertices are not collinear with the global color gamut center.

[0011] In an example embodiment, the step of determining that the selectable target chroma is between two adjacent vertices of the first plurality of vertices of the global common color gamut includes defining a global color gamut center by calculating an average of chroma values of color points at the first plurality of vertices of the global common color gamut; extending a line between the global color gamut center and each of the first plurality of vertices of the global common color gamut; and determining that the selectable target chroma is between the global color gamut center and the first plurality of vertices of the global common color gamut by calculating third and fourth directed distances between the selectable target chroma and the line extending between the global color gamut center and the two adjacent vertices of the global common color gamut.

[0012] In an example embodiment, the step of calculating the first and second directed distances includes defining a global color gamut center by calculating an average of chroma values of color points at the first plurality of vertices of the global common color gamut; extending a line between the global color gamut center and the selectable target chroma; projecting the line onto the global common color gamut; and calculating the first directed distance between the selectable target chroma and a first point at which the line intersects a transition boundary of the interior region, and the second directed distance between the selectable target chroma and a second point at which the line intersects a straight edge of the global common color gamut between the two adjacent vertices.

[0013] In an example embodiment, the method further includes determining not to modify the selectable target chroma when the selectable target chroma is within the interior region.

[0014] In an example embodiment, the method further includes determining to modify the selectable target chroma when the selectable target chroma is outside the interior region.

[0015] In an example embodiment, the method further includes modifying the selectable target chroma to a modified target chroma that is within the luminaire color gamut and outside the global common color gamut based at least in part on a relationship between the calculated first and second directed distances.

[0016] In an example embodiment, the method further includes computing a luminaire color gamut, wherein the luminaire color gamut at least partially encloses the global common color gamut and the luminaire color gamut includes a third plurality of vertices; and modifying the first color space bin to a second color space bin, wherein the first color space bin is defined by a straight edge of the global common color gamut, a transition boundary of the interior region, and a line extending between an endpoint of the straight edge and the transition boundary, and the second color space bin is defined by the transition boundary of the interior region and two adjacent vertices of the third plurality of vertices of the luminaire color gamut.

[0017] Generally, in another aspect, a system is provided. The system includes a plurality of LED-based light sources configured to generate light defined by a luminaire color gamut within a color space; and a controller. The controller is configured to receive or set a selectable target chromaticity within a global common color gamut of the color space; determine that the selectable target chromaticity is between two adjacent vertices of a first plurality of vertices of the global common color gamut; define an interior region within the global common color gamut with a transition boundary; and compute a first directed distance between the selectable target chromaticity and the transition boundary of the interior region, and a second directed distance between the selectable target chromaticity and a straight edge of the global common color gamut between the two adjacent vertices. The controller is further configured to modify the selectable target chromaticity to a modified target chromaticity within the luminaire color gamut based at least in part on the computed first and second distances, or generate an activation signal for driving the plurality of LED-based light sources based on the selectable target chromaticity based at least in part on the computed first and second directed distances.

[0018] In an example embodiment, the controller is further configured to generate another activation signal for driving the plurality of LED-based light sources based on the modified target chromaticity.

[0019] In an example embodiment, the luminaire color gamut at least partially encloses the global common color gamut, and the luminaire color gamut is defined by chromaticity properties of light emitted by the plurality of LED-based light sources.

[0020] In an example embodiment, the modified target chromaticity is outside the global common color gamut.

[0021] It will be appreciated that all combinations of the foregoing concepts (and additional concepts discussed below) (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, various claims below are considered to be supported by alternative combinations and subcombinations of the disclosed features. Particular reference will now be made to the Summary at the end of this disclosure for a comprehensive description of the subject matter of the application. BRIEF DESCRIPTION OF DRAWINGS

[0022] In the drawings, like reference numerals are generally used to refer to like elements throughout the several views, although references numbers can differ between different views. Additionally, the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the disclosure.

[0023] Figure 1 FIG. illustrates a schematic block diagram depicting a color illumination system according to the present disclosure.

[0024] Figure 2 FIG. illustrates a CIE chromaticity diagram including a single unique luminaire color gamut according to the present disclosure.

[0025] Figure 3 FIG. illustrates Figure 2 a CIE chromaticity diagram including two unique luminaire color gamuts according to the present disclosure.

[0026] Figure 4 FIG. illustrates a CIE chromaticity diagram including a unique luminaire color gamut and a global common color gamut within the luminaire color gamut according to the present disclosure.

[0027] Figure 4A FIG. illustrates another CIE chromaticity diagram including another unique luminaire color gamut and another global common color gamut not entirely within the luminaire color gamut according to the present disclosure.

[0028] Figure 5 FIG. illustrates Figure 4 a CIE chromaticity diagram including an inner region for accurate positioning of white points according to the present disclosure.

[0029] Figure 5A FIG. illustrates another CIE chromaticity diagram including another inner region for accurate positioning of white points according to the present disclosure.

[0030] Figure 6 is a flowchart illustrating a method of controlling LED-based lighting products to produce accurate white and saturated colors according to the present disclosure.

[0031] Figure 7 FIG. illustrates an example CIE chromaticity diagram showing a target chromaticity point within an inner region according to the present disclosure.

[0032] Figure 8 FIG. illustrates an example CIE chromaticity diagram showing a target chromaticity point within a global common color gamut and outside an inner region according to the present disclosure.

[0033] Figure 8A FIG. illustrates a zoomed-in view taken generally around Figure 8 block 8A in FIG..

[0034] Figure 9 FIG. illustrates another example CIE chromaticity diagram showing additional target chromaticity points within a global common color gamut and outside an inner region according to the present disclosure.

[0035] Figure 9A FIG. illustrates a zoomed-in view taken generally around Figure 9 block 9A in FIG..

[0036] Figure 9B Another example method for stretching a target point according to this disclosure is illustrated.

[0037] Figure 10 An example CIE chromaticity diagram according to this disclosure is illustrated, which shows an exemplary lighting fixture color gamut, an exemplary global common color gamut, and an exemplary non-overlapping internal region.

[0038] Figure 11 The illustration shows the following according to the present disclosure. Figure 10 The example CIE chromaticity diagram shows the first color space block.

[0039] Figure 12 The illustration shows the following according to the present disclosure. Figure 10 The example CIE chromaticity diagram shows the second color space block.

[0040] Figure 13 The illustration shows the following according to the present disclosure. Figure 10 The example CIE chromaticity diagram shows the blocks of the third color space.

[0041] Figure 14 The illustration shows an example CIE chromaticity diagram according to this disclosure, which demonstrates a chromaticity diagram based on... Figure 11 The first modified color space block shown is the first color space block of the first color space block.

[0042] Figure 15 The illustration shows an example CIE chromaticity diagram according to this disclosure, which demonstrates a chromaticity diagram based on... Figure 12 The second modified color space block shown is the second color space block in the second color space block.

[0043] Figure 16 The illustration shows an example CIE chromaticity diagram according to this disclosure, which demonstrates a chromaticity diagram based on... Figure 13 The third modified color space block shown is the third color space block.

[0044] Figure 17 An example CIE chromaticity diagram according to this disclosure is illustrated, showing the central portion of the lighting fixture color gamut optimized for color accuracy and the outer portion of the lighting fixture color gamut optimized for saturation. Detailed Implementation

[0045] The present disclosure describes various embodiments of systems and methods for controlling one or more LED-based lighting products to provide accurate white / soft color points and saturated color points without requiring changes to settings or reconfiguration of the lighting device. Applicant has recognized and appreciated that it would be beneficial to provide accurate white and full saturated shades of color within the same system without requiring reconfiguration. It is a particular goal with certain embodiments of the present disclosure to define an inner region of the operating color gamut to accurately locate white / soft colors while maintaining access to the entire color gamut of the lighting fixture to also provide saturated colors.

[0046] Reference is made to Figure 1 FIG. 1 illustrates a schematic block diagram depicting a color lighting system 100 including light sources 102A-C in accordance with the present disclosure. The light sources 102A-C are three narrowband, substantially monochromatic light sources, such as red, green, and blue light sources. The color lighting system 100 further includes a light source interface 104, a controller 106 including a microprocessor 108, a memory 110, and an external interface 112. The color lighting system 100 can be powered via an external power connection 113 or can use an internal power source such as a battery. Figure 1 The light sources 102A-C shown in FIG. 1 can be mounted in a single lighting fixture. However, it should be appreciated that any number of light sources and corresponding fixtures can be included in the color lighting system 100. The microprocessor 108 of the controller 106 is configured to receive a request for a selectable target chromaticity via the external interface 112 and, after processing, output one or more control signals to drive the light sources 102A-C via the light source interface 104. The light sources 102A-C are intensity controllable (dimmable) and can be controlled to output their respective colors of light at a relative intensity from 0-100%.

[0047] Although Figure 1 Red, blue, and green light sources 102A-C are shown, it should be appreciated that any source colors can be used. Additionally, it should be appreciated that any suitable number of light sources can be used, for example, additional or fewer light sources can be used. To illustrate the color generation capabilities of a lighting fixture including the light sources 102A-C, Figure 2A CIE chromaticity diagram, or color space or color system, is shown, including a triangular lighting fixture color gamut 114. In alternative embodiments, the lighting fixture color gamut can have a different shape (e.g., a polygon). The lighting fixture including the light sources 102A-C is configured to generate and mix red, green, and blue light in various combinations and proportions to create different temperatures of light. Each light source emits light that exhibits unique chromaticity characteristics, and these chromaticity characteristics can be mapped to corresponding points 116, 118, and 120 on the CIE chromaticity diagram having x and y chromaticity coordinates. The x and y chromaticity coordinates 116, 118, and 120 of the light sources 102A-C define a unique color gamut for the lighting fixture. The x and y chromaticity coordinates depend only on hue and saturation, and are independent of the amount of luminous energy. While the x and y chromaticity coordinates near the boundary of the lighting fixture color gamut 114 are more saturated, as a person moves from the boundary toward the center point of the lighting fixture color gamut 114, the colors become less saturated.

[0048] As discussed above, no two LEDs are exactly the same due to manufacturing variances inherent in LED technology; thus, another lighting fixture including red, green, and blue light sources will have a different lighting fixture color gamut. Figure 3 A CIE chromaticity diagram is shown, including two unique lighting fixture color gamuts 114 and 122. Figure 2

[0049] Applicants have recognized and appreciated that multiple lighting units, each configured to produce variable color light or variable color temperature white light based on additive mixing of multiple light sources, can not be capable of producing light of substantially the same range of colors or color temperatures, even if the lighting units generally employ similar light sources. If two or more such lighting units receive instructions (e.g., lighting commands) intended to cause the light from the multiple units to generate the same color (or color temperature), each lighting unit can actually generate light of a perceptibly different color (or color temperature) based at least in part on their respective different color gamuts (e.g., as determined by their respective different chromaticity coordinates of the "same color" source). If two or more such lighting units are deployed together, e.g., as components of a lighting system (e.g., to provide general illumination or other types of serial lighting in a given environment), inconsistent, unpredictable, and generally undesirable artifacts can result in the generation of variable color light or variable color temperature white light.

[0050] To consistently and predictably generate variable color light or variable color temperature white light in multiple lighting units, reference can be made to Figure 4 , Figure 4A and Figure 5 ​The global common color gamut 124 and internal region 126 shown are used to control the light source of multiple lighting units. The global common color gamut 124 can include all color points shared by two or more lighting units in the color space. Figure 4 As shown, the global common color gamut 124 can be completely enclosed within the color gamut of each luminaire in the lighting system device. For example... Figure 4A As shown, the global common color gamut 124 may alternatively not be completely enclosed within the color gamut of each luminaire within the lighting system apparatus. Figure 4A In this context, while vertices 125A and 125B are inside color gamut 114, vertex 125C is outside color gamut 114. The global common color gamut 124 can be generated in any suitable manner. An example method for generating the global common color gamut 124 involves determining the color gamut falling within the color gamut of each luminaire within the lighting system installation, regardless of whether the color gamut is a triangular polygon, a quadrilateral polygon, or some other shape. For the purposes of explaining this disclosure, as... Figure 4 , Figure 4A and Figure 5 We use a triangular global common color gamut, but any shape can be used. The global common color gamut 124 is a polygon formed by multiple straight edges S1-S3 and multiple vertices 125A-C. Each vertex 125A-C of the global common color gamut 124 is located at the intersection of two adjacent straight edges.

[0051] like Figure 5 As shown, a smaller inner region 126 is generated within the global common color gamut 124 to accurately locate the white point. The inner region 126 is defined by the same number of vertices used to define the global common color gamut and the boundaries connecting these vertices. Figure 4 , Figure 4A and Figure 5 As shown, the global common color gamut 124 has three vertices 125A-C, and as... Figure 5 As shown, the inner region 126 also has three vertices 127A-C. However, it should be understood that both can have additional vertices. In the example embodiment, as... Figure 5 As shown, each vertex of the inner region 126 is collinear with the center of the global common color gamut 124 and the vertices of the global common color gamut 124. Figure 5 Line L1-L3 is shown figuratively emanating from the center, passing through vertices 127A-C of the inner region 126, and ending at vertices 125A-C of the global common color gamut 124 to illustrate this collinearity.

[0052] In other example embodiments, each vertex of the inner region 226 does not need to have a relationship with... Figure 5 The same collinearity shown and described above. For example, in Figure 5AAs shown, the inner region 226 is defined by vertices 227A-C and the boundary connecting vertices 227A-C. The inner region 226 has the same number of vertices as the region used to define the global common color gamut 224. However, the vertices of the global common color gamut 224 and the inner region 226 are not collinear with the center of the global common color gamut 224. Line L4 extends from vertex 225A of the global common color gamut 224 and through vertex 227A of the inner region 226 to the ends of lines L5 and L6. Figure 5A As shown, line L5 terminates at a point closer to vertices 227A and 225A than line L6 terminates at the point where line L4 terminates. However, in an alternative embodiment, line L5 may terminate at a point further away from vertices 227A and 225A than line L6 terminates at the point where line L4 terminates. Line L5 extends from vertex 225B of the global common color gamut 224 and passes through vertex 227B of the inner region 226 to a point along line L4. In an alternative embodiment, line L5 may terminate at an endpoint of line L4. Line L6 extends from vertex 225C of the global common color gamut 224 and through vertex 227C of the inner region 226 to an endpoint of line L4; however, in an alternative embodiment, line L6 may terminate at a point along line L4. Figure 5A In this context, none of lines L4-L6 extend through or reach the center of the global common color gamut 224. However, it should be understood that any other suitable configuration can be considered as long as vertices 225A and 227A are connected along line L4, vertices 225B and 227B are connected along line L5, and vertices 225C and 227C are connected along line L6. The portion of line L4-L6 between the global common color gamut 224 and the inner region 226 defines the color space blocks discussed below.

[0053] The inner region 126 must be completely surrounded by the global common color gamut 124, but it should also be large enough to encompass all white points that are desired to be accurately located. The center of the global common color gamut 124 is obtained by averaging the x and y chromaticity coordinates of the vertices 125A-C of the global common color gamut 124. Any optional target chromaticity within the inner region 126 received by the microprocessor 108 of the controller 106 is accurately located. In other words, any such optional target chromaticity within the inner region 126 is used as is, and the microprocessor 108 ceases further processing, as further described below. In the example embodiment, lighting commands received by multiple lighting units can be appropriately processed in each lighting unit based on a predetermined relationship between the lighting command and the inner region 126.

[0054] As further described below, to also generate saturated colors among the plurality of lighting units, the light sources 102A-C can be controlled with reference to the independent lamp color gamut(s) and the global common color gamut 124 and the inner region 126. As used herein, the term "saturated" refers to the amount of saturation of any color that is within the independent lamp color gamut(s) 114 and outside the inner region 126. These colors outside the inner region 126 are more saturated (i.e., have less white) than colors inside the inner region 126. The term "saturated" refers to all colors, including colors on the boundary of the independent lamp color gamut(s) and colors within the boundary but outside the boundary of the inner region 126. The term "fully saturated" is used to refer to those colors that lie on the boundary of the global common color gamut 124 or the lamp color gamut(s) 114 in the appropriate context. In other words, color points that are specified on the boundary of the global common color gamut 124 before the microprocessor 108 executes any modifications according to the present disclosure can be considered "fully saturated" points. After the microprocessor 108 executes modifications according to the present disclosure, color points that lie on the boundary of the lamp color gamut 114 can be considered "fully saturated" points.

[0055] As used herein for purposes of the present disclosure, the term "LED" should be understood to include any electroluminescent diode or other type of carrier injection / junction- based light source that is capable of generating radiation in response to an electric signal. Thus, the term LED includes, but is not limited to, various semiconductor-based structures that emit light in response to electric

[0056] It should also be understood that the term LED does not limit the physical and / or electrical package type of the LED. For example, as discussed above, an LED can refer to a single light emitting device with multiple dies that are configured to emit different spectra of radiation (e.g., that can or can not be individually controllable). Also, an LED can be associated with a phosphor that converts the spectrum of incident radiation to a different spectrum of radiation

[0057] The term "light source" should be understood to include any one or more of a variety of light sources, including without limitation, LED-based sources (including one or more LEDs as defined above), incandescent sources (e.g., filament lamps, halogen lamps), fluorescent, phosphorescent, high-intensity discharge, lasers, other types of electroluminescent sources, high-temperature resistive heating elements, flame-based sources, candle-based sources, gas-discharge sources, cathodically-pumped sources, electroluminescent sources, crystalline sources, kinescope sources, pyro-luminescent sources, photoluminescent sources, and luminescent polymers.

[0058] As used herein, the terms "lighting unit" and "light fixture" refer to an assembly that includes one or more light sources of same or different types. A given lighting fixture can have any suitable arrangement of mounting of the light source(s), enclosure / housing arrangement and shape, and / or electrical and mechanical connections. Additionally, a given lighting fixture can further include, be coupled to, and / or packaged with other components (e.g., control circuitry) relevant to the operation of the light source(s). An "LED-based lighting fixture" refers to a lighting fixture unit that includes one or more LED-based light sources as specified above, either alone or in combination with other non LED-based light sources.

[0059] As used herein, the term "controller" refers to various apparatuses that are relevant to the operation of one or more light sources. A controller can be implemented in dedicated hardware, using one or more microprocessors, which are programmed using software to perform the various functions discussed herein, or a combination of dedicated hardware and programmed microprocessors, along with associated circuitry, to perform some functions discussed herein. Examples of controller components that can be employed in various embodiments of the present application include, but are not limited to, microprocessors, application specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs).

[0060] In various embodiments, a controller can be associated with one or more storage media (generically referred to herein as "memory," e.g., volatile and non-volatile computer memory such as RAM, PROM, EPROM, and EEPROM, floppy disks, compact disks, optical disks, tape, etc.). In some implementations, the storage media can be encoded with one or more programs that, when executed on one or more processors and / or controllers, perform at least some of the functions discussed herein. Various storage media can be fixed within a processor or controller or can be transportable, such that the one or more programs stored thereon can be loaded into a processor or controller so as to implement various aspects of the present application discussed herein.

[0061] Reference will now be made to Figure 6The process of using the color illumination system 100 to target accurate white points and saturated colors is described. It should be understood that various embodiments can not include reference to the Figure 6 Each of the steps described, and the order of the steps, is not limited. That is, in other embodiments, the process can be performed in an order different than described without leaving the scope of the present disclosure.

[0062] The luminaire color gamut 114, the global common gamut 124, and the inner region 126 must be defined at step S602 before the controller 106 of the color illumination system 100 is able to determine whether to output one or more control signals via the light source interface 104 to drive the light sources 102A-C.

[0063] The at least one luminaire color gamut 114 can be pre-defined and pre-programmed by the manufacturer of the luminaire and stored in the memory 110. Alternatively, any suitable tool can be used to calculate the luminaire color gamut to measure the chromaticity of the light source of the luminaire and stored in the memory 110. For example, the spectral power distribution of the light source can be measured and mapped to a color space, such as a CIE chromaticity diagram. Such data can then be stored in the memory 110. In some embodiments, the luminaire color gamut is temperature dependent, so it can be calculated and recalculated as needed.

[0064] The global common gamut 124 of the luminaire or of a system comprising multiple luminaires can also be pre-defined and pre-programmed by the manufacturer and stored in the memory 110. Alternatively, a professional lighting installer or another user can define a gamut containing the same color points as all of the luminaires in the system and store it in the memory 110. In example embodiments, the global common gamut can contain the same majority but not all of the color points as all of the luminaires in the system. In the particular case where the global common gamut does not fully contain within the color gamut of the luminaire, any suitable region mapping can be used to modify the color points selected in the global common gamut and outside of the luminaire color gamut. In other embodiments, a computer program product can be configured to determine a gamut containing the same color points as all or a majority of the luminaires in the system and store it in the memory 110. The center of the global common gamut 124 can also be defined by the manufacturer or other ways described herein and stored in the memory 110.

[0065] The inner region 126 of the global common gamut 124 can be pre-defined and pre-programmed by the manufacturer and stored in the memory 110. Otherwise, a professional lighting installer or some other user can define the inner region 126 to customize all of the white points to be targeted accurately. In other embodiments, a computer program product can be configured to determine the inner region 126 based on the input(s) of all of the white points to be targeted accurately and stored in the memory 110.

[0066] Once the luminaire color gamut 114, the global common color gamut 124, and the inner region 126 are defined, a user-selectable target chromaticity can be received or set via the external interface 112 at step S604. For example, a user can input a target chromaticity via the external interface in the form of red, green, and blue values as numbers varying from 0 to 255, which can be processed according to the DMX-512 protocol (wherein eight bits are used to specify the relative intensity of each light source; i.e., 24-bit color control). It should be appreciated, however, that virtually any scale can be employed in any of a variety of lighting command formats to specify the relative amounts of individual sources in a given lighting unit to generate a resulting color or color temperature of light. In example embodiments, the DMX values can be weighted values and can employ a dimming curve.

[0067] After the microprocessor 108 receives the user-selectable target chromaticity, it is determined at step S606 whether the target chromaticity is between two adjacent vertices of the global common color gamut 124. For example, with reference to Figure 5 and Figure 7 the microprocessor 108 can divide the global common color gamut 124 into three regions based on the number of vertices of the global common color gamut and determine which region the target chromaticity is in. Since the global common color gamut 124 has red, green, and blue points, the global common color gamut 124 can be divided into regions RG, GB, and BR as shown in FIG. 1 using the lines L1-L3 discussed above. The user-selectable target chromaticity can be in any one of the three regions. To determine which region the target chromaticity is in, the equation of each line L1-L3 can be derived and the directed distance between the target chromaticity and each line can be calculated to determine whether the target chromaticity is above or below each line (or outward or inward of each line with respect to the center point). Since these lines do not change, they can be calculated at the time the global common color gamut 124 is defined and stored in the memory 110. The following equations can be used to define each line: Figure 5

[0068]

[0069] where a represents the slope, and b represents the y-intercept. With reference to Figure 5 Equation (1) above defines line L2, Equation (2) above defines line L1, and Equation (3) above defines line L3.

[0070] Once the microprocessor 108 determines which region the target chromaticity is in, the microprocessor 108 can ignore the other regions at step S608. With reference to Figure 7 ​In example embodiments, the target chromaticity point P1 is in the GB region, between the center-green line (e.g., line L1) and the center-blue line (e.g., line L3), and the microprocessor 108 focuses on this region. The microprocessor 108 can then use the equations y = ax + b to define the transition boundary 130 of the inner region 126 between vertices 127A and 127C and the boundary 132 of the global common color gamut 124 between vertices 125A and 125C.

[0071] The microprocessor 108 can then calculate the directed distances between the target chromaticity point P1 and each of the boundaries 130 and 132 at step S610. For example, the microprocessor 108 can calculate d P-b1 , which represents the distance between the target chromaticity point P1 and the boundary 130 (or b1), and d P-b2 , which represents the distance between the target chromaticity point P1 and the boundary 132 (or b2). These distances can be defined as the shortest distance between the target chromaticity point and the respective boundary. Although the boundaries 130 and 132 are not necessarily parallel, in all practical applications they will be nearly parallel. Using the shortest distance is a way of treating them as equally valid slopes that can or can not be parallel. These boundaries 130 and 132 will not be perpendicular in practical implementations. The directed distances discussed above can be calculated using the following equations:

[0072]

[0073] Since K is a function (e.g., a cosine function) of a , it should be understood that K has six possible values, that is, two for the boundaries 130 and 132 discussed herein, another two for the boundaries of the global common color gamut and the inner region between vertices 125A and 127A and vertices 125B and 127B (e.g., within region RG), and another two for the boundaries of the global common color gamut and the inner region between vertices 125B and 127B and vertices 125C and 127C (e.g., within region BR). Thus, the calculations of d P-b1 and d P-b2 use two different K values, that is, one for b1 and another for b2. Since K is a pre-known scaling factor and can be pre-calculated as a factory setting, it can be stored in the memory 110. It should also be appreciated that the equations for d K"±" as used herein indicates that the sign representing the desired direction should be chosen so that the positive distance is oriented away from / more distant from the center 128 and the negative distance is oriented toward / more toward the center 128. For example, for blue-green or yellow, the positive distance points outward from the center, but for purple, the positive distance points inward toward the center. The correct sign should be used so that the positive distance is oriented away from / more distant from the center 128.

[0074] It should be appreciated that the directed distance can also be determined in other ways. For example, a line can be drawn that connects the center of the global common color gamut discussed herein to the target chromaticity point P1. The line from the center to the point P1 can be projected onto the global common color gamut. The distance d P-b1 and d P-b2 A single projection line calculation can be used. This is particularly applicable in the case where the global common color gamut and the inner region are parallel or substantially parallel.

[0075] At step S612, based on the directed distance, the microprocessor 108 can determine whether the target chromaticity point P1 is within the transition boundary 130 of the inner region 126 or between the transition boundary 130 of the inner region 126 and the boundary 132 of the global common color gamut 124. If the target chromaticity point P1 is within the transition boundary 130 of the inner region 126 (as shown in FIG. 6B), then the user has selected a white point that can be accurately located. In that case, the directed distance d Figure 7 and d P-b1 and d P-b2 will both be negative because the target chromaticity point P1 is inside of b1 and b2 relative to the center. In other words, when the directed distances d P-b1 and d P-b2 are both negative, both boundaries b1 and b2 are outside of the target chromaticity point P1 relative to the center of the global common color gamut. When the directed distances are both negative, the microprocessor 108 uses the input values as-is for outputting control signals to the light sources 102A-C at step S614A. In other words, the final target chromaticity is the requested target chromaticity. No further processing is needed when the target chromaticity point is within the transition boundary 130 of the inner region 126. As shown in FIG. 6C, the input DMX values for R, G, and B of the global common color gamut 124 represent a point P1 that is within both the global common color gamut 124 and the inner region 126. Thus, the accuracy of the color lighting system 100 is optimized using the control parameters of the inner region 124. Figure 7

[0076] On the other hand, as described further below, if the target chromaticity point is between the transition boundary 130 of the inner region 126 and the boundary 132 of the global common color gamut 124, then the microprocessor 108 can output modified control signals to the light sources 102A-C. As shown in FIG. 6D, the input DMX values for R, G, and B of the global common color gamut 124 represent a point P1 that is between the transition boundary 130 of the inner region 126 and the boundary 132 of the global common color gamut 124. Thus, the accuracy of the color lighting system 100 is optimized using the control parameters of the inner region 124. Figure 8 and Figure 8A ​As shown in FIG. 12B, the input DMX values of R, G, and B using the global common color gamut 124 can represent a point P2 that lies between the transition boundary 130 of the inner region 126 and the boundary 132 of the global common color gamut 124. Since the point P2 is outside the inner region 126, the user is expressing an intent for a more saturated color and the microprocessor 108 can stretch the point to a modified target chromaticity. Based on the values of the point P2 represented in Figure 8 and Figure 8A the directed distance d P-b1 will be positive and the directed distance d P-b2 will be negative. This is because the point P2 is outside (or above) the transition boundary 130 and inside (or below) the boundary 132 with respect to the center point 128. In other words, the target point P2 is above the transition boundary 130 and below the boundary 132. When at least one of the directed distances is positive, the microprocessor 108 determines at step S614B that the input values must be modified in an outward direction toward the boundary 132 of the global common color gamut 124 and the luminaire color gamut 114. The input values modified in the outward direction specify a more saturated color than originally requested.

[0077] To determine how far to stretch the target chromaticity point in the outward direction, the microprocessor 108 can calculate at step S616 the fractional distance of the point between the boundaries 130 and 132, represented by the ratio R and 1-R. The ratio R can be expressed using the absolute values of the directed distances as follows:

[0078]

[0079] When added together, the ratio R and 1-R equal 1 or 100%. The ratio R indicates whether the target chromaticity point is closer to the transition boundary 130 of the inner region 126 or the boundary 132 of the global common color gamut 124. When the point is closer to the transition boundary 130, the ratio R is greater because the distance between the point and the boundary 132 is greater than the distance between the point and the transition boundary 130. When the point is closer to the boundary 132, the ratio R is smaller because the distance between the point and the boundary 132 is less than the distance between the point and the transition boundary 130. When the point is closer to the transition boundary 130 of the inner region 126, the weighted average will favor the chromaticity to approach the user target color point. Conversely, when the point is closer to the boundary 132 of the global common color gamut 124, the weighted average will disfavor the chromaticity to approach the user target color point. As shown in Figure 8 and Figure 8A based on the location of the point P2, the microprocessor 108 stretches the point to a modified target chromaticity MP2. In Figure 8 and Figure 8A the modified target chromaticity MP2 is adjacent to the target chromaticity point P2 and slightly outward. In Figure 8 and Figure 8AThe modified target chromaticity MP2 is still within the global common color gamut 124.

[0080] As shown in Figure 9 and Figure 9A based on the location of point P3, the microprocessor 108 stretches the point to a modified target chromaticity MP3. Figure 9 The modified target chromaticity MP3 is no longer within the global common color gamut 124. Instead, the modified target chromaticity MP3 is stretched outward beyond the global common color gamut 124 and into the portion of the luminaire color gamut 114 that does not overlap the global common color gamut 124. As shown in Figure 9 and Figure 9A based on the location of point P4, the microprocessor 108 stretches the point P4 to a modified target chromaticity MP4 that is also outside the global common color gamut 124 and in the luminaire color gamut 114. Figure 9 and Figure 9A shows how a small difference in saturation in the user-selected target points (P3 vs. P4) results in a large difference in saturation in the modified chromaticity points (MP3 vs. MP4). In other words, because P4 is slightly more saturated than P3, the modified point MP4 is more saturated than the modified point MP3 due to the stretching performed by the microprocessor 108 as discussed herein. In example embodiments, the modified target chromaticity can be determined from the input dimming ratio as the modified target chromaticity is applied to the color gamut of the luminaire.

[0081] If the input values of R, G, and B include one or more values equal to 0, this will result in the above ratio R being zero, and the microprocessor 108 positions a fully saturated color limited only by the optical capabilities of the LEDs of the lighting unit or fixture. On the other hand, if the input values represent a color of low saturation, the ratio R is larger, and the microprocessor blends between the requested color and the most saturated possible color.

[0082] In example embodiments, as the user changes the DMX input values, the fixture gradually responds to these changes by blending between the accurate white / soft colors and the saturated colors.

[0083] In example embodiments, the microprocessor 108 can alternatively determine how far to stretch the target chromaticity point in the outward direction. Instead of using the fractional distance of the point between the boundaries 130 and 132 discussed above, as shown in Figure 9B a line L6 connecting the center 128 of the global common color gamut to the target point P5 can be drawn, and the line can be projected onto the global common color gamut 124. As shown in Figure 9B the target point P5 can represent a distance A and B as well as a distance d P-b1 and d P-b2A and line L6 intersects the transition boundary 130 of the inner region 126. The microprocessor 108 can calculate the stretched target chroma (e.g., MP5) as the same ratio A and B, but applied to the transition boundary 130 and the equipment gamut line 114A. In other words, the target point P5 is a weighted average of the end point of the transition boundary 130 and the end point of the boundary 132. The stretched target uses the same weighted average, but applied to the transition boundary 130 and the boundary 114A of the equipment gamut.

[0084] In example embodiments, the process of stretching a target chroma point in the outward direction involves stretching the color space patch 134 in the global common gamut 126. For example, Figure 10 The inner region 126 and the patch 134 between the inner region 126 and the outer portion of the global common gamut 124 are shown. As discussed above, since the inner region 126 remains constant, all equipment can accurately locate a requested point in the patch 126. A requested point between the inner region 126 and the outer portion of the global common gamut 124 can be stretched as described above to produce a saturated color. In example embodiments, the color space patch 134 or portions thereof can also be stretched.

[0085] As shown in Figures 11-13 , the patch 134 can be divided into sub-patches 136, 138, and 140. In example embodiments, the microprocessor 108 can divide the patch 134 into three sub-patches based on the number of vertices of the global common gamut 124 and the inner region 126. In examples, this sub-division can be performed after or concurrently with the determination by the microprocessor 108 of which region a target chroma is located in as described above. For example, the sub-patch 136 is the portion of the global common gamut 124 that does not overlap with the inner region 126 and is located between lines LI and L3 in Figure 11 . Similarly, the sub-patch 138 is the portion of the global common gamut 124 that does not overlap with the inner region 126 and is located between lines LI and L2 in Figure 12 . The sub-patch 140 is also the portion of the global common gamut 124 that does not overlap with the inner region 126 and is located between lines L2 and L3 in Figure 13 .

[0086] Referring to Figures 14-16 , the sub-patches 136, 138, and 140 can be modified to sub-patches 142, 144, and 146, respectively. For example, in Figure 14The sub-blocks 136 (otherwise referred to in this disclosure as color space blocks) in FIG. 1 can be modified such that the outer boundaries of the sub-blocks 136 are limited only by the optical capabilities of the LEDs of the lighting unit or fixture. When a target chromaticity point is determined to be within a color space block 136, the sub-block 136 can be modified to a sub-block or color space block 142. Referring back to FIG. 1, Figure 11 The color space block 136 is defined by the transition boundary 130 of the inner region 126, the boundary 132 of the global common color gamut 126, and portions of the lines LI and L3 extending between the center 128 and the vertices 125A and 125C of the global common color gamut 126. Figure 14 The color space block 142 in FIG. 1 is defined by the transition boundary 130 of the inner region 126 and two adjacent vertices 150 and 152 of the plurality of vertices 150, 152, 154 of the lighting fixture color gamut 114.

[0087] Similarly, the color space blocks 138 and 140 can be modified such that their outer boundaries are limited only by the optical capabilities of the LEDs of the lighting unit or fixture as appropriate. For example, when a target chromaticity point is determined to be within the color space block 138, Figure 12 The color space block 138 in FIG. 1 can become Figure 15 The color space block 144 in FIG. 1, and when a target chromaticity point is determined to be within the color space block 140, Figure 13 The color space block 146 in FIG. 1 can become Figure 16 The color space block 146 in FIG. 1. Figure 17 The modified color space blocks 142, 144, and 146 are shown in combination relative to the inner region 126.

[0088] Advantageously, the systems and methods described herein enable a user to easily select accurate white / soft color points and saturated colors in the content of an LED-based lighting system without changing settings or reconfiguring the lighting device.

[0089] While several inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which a inventive embodiment is used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that inventive embodiments can be practiced within the scope of the following claims and any equivalents thereto. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

Claims

1. A method for driving multiple LED-based light sources with selectable target chromaticity in a color space, the method comprising: Receive or set (S604) the optional target chromaticity within the global common color gamut (124) of the color space, wherein the global common color gamut (124) includes one or more color points shared by two or more of the plurality of LED-based light sources in the color space; Determine (S606) the optional target chromaticity between two adjacent vertices in the first plurality of vertices of the global common color gamut (124); The internal region (126) within the global common color gamut (124) is defined by the transition boundary (S602); Calculate (S610) the first directed distance (d) between the optional target chromaticity and the transition boundary of the inner region. P-b1 The second directed distance (d) between the optional target chromaticity and the straight edge of the global common color gamut between the two adjacent vertices. P-b2 );as well as The optional target chromaticity is modified to a modified target chromaticity within the luminaire color gamut (114) based at least in part on calculated first and second directional distances, the modification being made in a direction outward toward the boundary of the global common color gamut and the luminaire color gamut (114) including color points generated by at least one of the plurality of LED-based light sources, or based on the optional target chromaticity to generate an activation signal for driving the plurality of LED-based light sources within the inner region.

2. The method according to claim 1, further comprising: Calculating the luminaire color gamut, wherein the luminaire color gamut at least partially surrounds the global common color gamut, wherein the step of calculating the luminaire color gamut includes determining or receiving chromaticity data indicating the chromaticity characteristics of light emitted by the plurality of LED-based light sources, wherein the chromaticity characteristics define the luminaire color gamut.

3. The method according to claim 2, wherein the luminaire color gamut completely surrounds the global common color gamut.

4. The method of claim 1, wherein the step of defining the internal region comprises: The global color gamut center is defined by calculating the average of the chromaticity values ​​of the color points at the first plurality of vertices of the global common color gamut (128); Extend a line between the center of the global color gamut and each of the first plurality of vertices of the global common color gamut; as well as Locate a second plurality of vertices such that each of the second plurality of vertices intersects one of the lines extending between the global color gamut center and each of the first plurality of vertices, and the transition boundary connects the second plurality of vertices.

5. The method of claim 1, wherein the step of defining the internal region comprises: The global color gamut center is defined by calculating the average of the chromaticity values ​​of the color points at the first plurality of vertices of the global common color gamut (128); Locate a second plurality of vertices such that each vertex in the second plurality of vertices is between the global color gamut center and the vertices of the first plurality of vertices; as well as The transition boundary connecting the second plurality of vertices; The first plurality of vertices and the second plurality of vertices are not collinear with the center of the global color gamut.

6. The method of claim 1, wherein the step of determining the optional target chromaticity between two adjacent vertices of the first plurality of vertices in the global common color gamut comprises: The global color gamut center is defined by calculating the average of the chromaticity values ​​of the color points at the first plurality of vertices of the global common color gamut (128); Extend a line between the center of the global color gamut and each of the first plurality of vertices of the global common color gamut; as well as The optional target chromaticity is determined between two adjacent lines extending between the global gamut center and two adjacent vertices of the global common gamut by calculating the third and fourth directed distances between the optional target chromaticity and the lines extending between the global gamut center and two adjacent vertices of the global common gamut.

7. The method according to claim 1, wherein the step of calculating the first directed distance and the second directed distance comprises: The global color gamut center is defined by calculating the average of the chromaticity values ​​of the color points at the first plurality of vertices of the global common color gamut (128); Extend a line between the center of the global color gamut and the optional target chromaticity; Project the line onto the global common color gamut; as well as Calculate a first directed distance between the optional target chromaticity and a first point where the line intersects the transition boundary of the internal region, and a second directed distance between the optional target chromaticity and a second point where the line intersects the straight edge of the global common color gamut between the two adjacent vertices.

8. The method of claim 1, further comprising determining to modify the optional target chromaticity when the optional target chromaticity is outside the inner region.

9. The method of claim 1, further comprising modifying the optional target chromaticity to a modified target chromaticity within the luminaire color gamut and outside the global common color gamut, at least in part based on the calculated relationship between the first directed distance and the second directed distance.

10. The method according to claim 1, further comprising: Calculate the luminaire color gamut, wherein the luminaire color gamut at least partially surrounds the global common color gamut and the luminaire color gamut includes a third plurality of vertices; as well as The first color space block is modified into a second color space block, wherein the first color space block is defined by the straight edge of the global common color gamut, the transition boundary of the internal region, and the line extending between the endpoint of the straight edge and the transition boundary, and the second color space block is defined by the transition boundary of the internal region and two adjacent vertices among the third plurality of vertices of the luminaire color gamut.

11. A system for driving multiple LED-based light sources with selectable target chromaticity in a color space, comprising: Multiple LED-based light sources are configured to produce light defined by the luminaire color gamut (114) within a color space; and The controller (108) is configured as follows: Receive or set optional target chromaticity within the global common color gamut (124) of the color space, wherein the global common color gamut (124) includes one or more color points shared by two or more of the plurality of LED-based light sources in the color space; The optional target chromaticity is determined between two adjacent vertices in the first plurality of vertices of the global common color gamut; The internal region within the global common color gamut is defined by the transition boundary (126); Calculate the first directed distance (d) between the optional target chromaticity and the transition boundary of the interior region. P-b1 The second directed distance (d) between the optional target chromaticity and the straight edge of the global common color gamut between the two adjacent vertices. P-b2 ); as well as The optional target chromaticity is modified to a modified target chromaticity within the luminaire color gamut, at least in part based on calculated first and second distances, the modification being made in a direction outward toward the boundary of the global common color gamut and the luminaire color gamut (114), which includes color points generated by at least one of the plurality of LED-based light sources, or based on the optional target chromaticity to generate an activation signal for driving the plurality of LED-based light sources.

12. The system according to claim 11, wherein, The controller is also configured to generate activation signals for driving the plurality of LED-based light sources based on the modified target chromaticity.

13. The system according to claim 11, wherein, The luminaire color gamut at least partially surrounds the global common color gamut, and the luminaire color gamut is defined by the chromaticity characteristics of the light emitted by the plurality of LED-based light sources.

14. The system according to claim 11, wherein, The modified target chromaticity is outside the global common color gamut.

Images