CN115720727B - Control design for perceptually uniform color adjustment - Google Patents

Abstract

Various embodiments include apparatus and methods for controlling a device to color adjust an array of Light Emitting Diodes (LEDs). In one particular example, a control device for color adjustment of an array of Light Emitting Diodes (LEDs) is disclosed for perceptually uniform color adjustment. The apparatus includes a Correlated Color Temperature (CCT) control device that is adjustable by an end user to a desired color temperature of the LED array and generates an output signal corresponding to the desired color temperature. The storage device is electrically coupled to the CCT control device to correlate a mechanical range of movement of the CCT control device to provide a substantially uniform increase in perceived CCT value from the LED array based on the set of N predetermined values. Other apparatus and methods are described.

Description

Control design for perceptually uniform color adjustment

Priority claim

The present utility model claims the benefit of priority from european patent application No. 19207130.6, filed 11/5/2019, entitled "perceptually uniform color-regulated control design", which claims the benefit of priority from U.S. patent application No. 16/528108, filed 7/31/2019, each of which is incorporated herein by reference in its entirety.

Technical Field

The subject matter disclosed herein relates to color adjustment of one or more Light Emitting Diodes (LEDs) or LED arrays that include lamps that operate substantially in the visible portion of the electromagnetic spectrum. More particularly, the disclosed subject matter relates to a technique that enables, for example, user-controlled design methods and apparatus to create a perceptually uniform color-adjusting experience for one or more LEDs or LED arrays.

Background

Light Emitting Diodes (LEDs) are commonly used in various lighting operations. The color appearance of an object is determined in part by the Spectral Power Density (SPD) of the light illuminating the object. For a person viewing an object, an SPD is the relative intensity of various wavelengths within the visible spectrum. However, other factors may also affect the color appearance. Furthermore, both the Correlated Color Temperature (CCT) of the LEDs and the distance of the LEDs on the CCT from the black body line (BBL, also known as the black body locus or planckian locus) can affect the perception of an object by a person.

There are currently two main techniques for color adjustment (e.g., white adjustment) of LEDs. The first technology is based on white LEDs of two or more CCTs. The second technique is based on a combination of red/green/blue/amber. The first technique does not have at all the following D _uv The ability to adjust the LED in the direction. In the second technique, color adjustment capability is rarely provided as an available function.

The information described in this section is provided to provide the skilled artisan with a background for the subject matter disclosed below and should not be construed as an admission that it is prior art.

Drawings

FIG. 1 shows a portion of an International Commission on illumination (CIE) color chart, including the Black Body Line (BBL);

FIG. 2A shows a chromaticity diagram having approximate chromaticity coordinates for colors of typical red (R), green (G), and blue (B) LEDs, and including a BBL;

FIG. 2B shows a revised version of the chromaticity diagram of FIG. 2A with approximate chromaticity coordinates of the desaturated R, G and B LEDs near the BBL, the desaturated R, G and B LEDs having a Color Rendering Index (CRI) of about 90+ and within a defined range of color temperatures, in accordance with various embodiments of the disclosed subject matter;

FIG. 2C shows a revised version of the chromaticity diagram of FIG. 2A with approximate chromaticity coordinates of the desaturated R, G and B LEDs approaching the BBL, the desaturated R, G and B LEDs having a Color Rendering Index (CRI) of about 80+ and within a defined color temperature range that is wider than the desaturated R, G and B LEDs of FIG. 2B, in accordance with various embodiments of the disclosed subject matter;

FIG. 3 illustrates a prior art color adjustment device requiring a hardwired flux control device and a separate hardwired CCT control device;

FIG. 4 is an exemplary embodiment of a graph showing CCT values as a function of control input values and illustrating differences between two user control designs in accordance with various embodiments of the disclosed subject matter;

FIG. 5 illustrates an exemplary embodiment of a series of selected control points along the BBL in accordance with various embodiments of the disclosed subject matter;

FIG. 6 illustrates an exemplary method process flow diagram for determining control equipment points of a CCT adjustment curve; and

fig. 7 illustrates a simplified block diagram of a machine in the example form of a computing system within which a series of instructions for causing the machine to perform any one or more of the methods and operations discussed herein (e.g., CCT next determination) may be executed.

Detailed Description

The disclosed subject matter will now be described in detail with reference to a few general and specific embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the disclosed subject matter. It will be apparent, however, to one skilled in the art, that the disclosed subject matter may be practiced without some or all of these specific details. In other instances, well-known process steps or structures have not been described in detail in order to not obscure the disclosed subject matter.

Examples of different light illumination system and/or light emitting diode ("LED") embodiments and devices for controlling those embodiments are described more fully below with reference to the accompanying drawings. The examples are not mutually exclusive and features found in one example may be combined with features found in one or more other examples to implement further embodiments. Accordingly, it will be understood that the examples shown in the accompanying drawings are provided for illustrative purposes only and are not intended to limit the present disclosure in any way. Like numbers generally refer to like elements throughout.

Further, it will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms may be used to distinguish one element from another element. For example, a first element could be termed a second element, and a second element could be termed a first element, without departing from the scope of the disclosed subject matter. As used herein, the term "and/or" may include any and all combinations of one or more of the associated listed items.

It will also be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element and/or be connected or coupled to the other element via one or more intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present between the element and the other element. It will be understood that these terms are intended to encompass different orientations of the element in addition to any orientation depicted in the figures.

Relative terms such as "below," "above," "upper," "lower," "horizontal" or "vertical" may be used herein to describe one element, region or zone's relationship to another element, region or zone as illustrated in the figures. Those of ordinary skill in the art will understand that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. Further, whether the LEDs, LED arrays, electrical components, and/or electronic components are housed on one, two, or more electronic boards or in one or more physical locations may also depend on design constraints and/or specific applications.

Semiconductor-based light emitting devices or optical power emitting devices, such as devices that emit Ultraviolet (UV) or Infrared (IR) optical power, are among the most efficient light sources currently available. These devices may include light emitting diodes, resonant cavity light emitting diodes, vertical cavity laser diodes, or edge emitting lasers, etc. (herein simply referred to as "LEDs"). LEDs can be attractive candidates for many different applications due to their compact size and low power requirements. For example, they may be used as light sources (e.g., flash and camera flash) for handheld battery powered devices such as cameras and cell phones. For example, LEDs may also be used for automotive lighting, head-up display (HUD) lighting, gardening lighting, street lighting, video lighting (torch for video), general lighting (e.g., home, store, office, and studio lighting, theatre/stage lighting, and architectural lighting), augmented Reality (AR) lighting, virtual Reality (VR) lighting, backlighting as a display, and IR spectrometers. A single LED may provide light that is less bright than an incandescent light source, and thus, a multi-junction device or LED array (such as a monolithic LED array, micro LED array, etc.) may be used in applications where enhanced brightness is desired or required.

In various environments where LED-based lamps (or related lighting devices) are used to illuminate objects and for general lighting, it may be desirable to control aspects of the color temperature of a plurality of LED-based lamps (or a single LED-based lamp) in addition to the relative brightness (e.g., luminous flux) of the lamps. Such environments may include, for example, retail establishments and hotel venues, such as restaurants, etc. In addition to CCT, another lamp metric is the Color Rendering Index (CRI) of the lamp. CRI is defined by the international commission on illumination (CIE) and provides a quantitative measure of the ability of any light source, including LEDs, to accurately represent the color of various objects, as compared to an ideal or natural light source. The highest possible CRI value is 100. Another quantitative lamp metric is D _uv 。D _uv Is a measure, e.g. defined in CIE 1960, for representing the distance of the color point from the BBL. If the color point is above the BBL, it is positive; and if the color point is below the BBL it is negative. The color points above the BBL represent light green colors and the color points below the BBL represent light pink colors. The disclosed subject matter provides a control of color temperature (CCT and D) with a smooth and visually pleasing tuning experience _uv ) Is provided. Such asCCT and D in color temperature and color adjustment applications as described herein _uv Both of which are related.

As is known in the relevant art, the forward voltage of a direct color LED decreases with increasing dominant wavelength. For example, the LEDs may be driven with a multi-channel DC-to-DC converter. Advanced phosphor-converted color LEDs targeting high efficiency and CRI have been created, providing new possibilities for Correlated Color Temperature (CCT) tuning applications. Some advanced color LEDs have desaturated color points and can be mixed to achieve a white color with 90+ CRI over a wide CCT range. Other LEDs having an 80+cri implementation or even a 70+cri implementation (or even lower CRI values) may also be used with the disclosed subject matter. These possibilities use LED circuits that enable and increase or maximize this potential. At the same time, the control device described herein is compatible with single channel constant current drivers to facilitate market adoption.

An advantage of the disclosed subject matter over the prior art is that the desaturated red-green-blue (RGB) LED methods described in detail below can create dimmable over and under (on and off) the BBL, as well as over the BBL, e.g., over isothermal CCT lines (described below), while maintaining a high CRI. In contrast, various other prior art systems utilize a CCT method in which the tunable dots fall on a straight line between two primary colors of LEDs (e.g., R-G, R-B or G-B).

In general, color adjustment is an integral part of human-centered illumination. Advanced LED-based systems, such as the desaturated RGB LED approach and related control techniques, offer new possibilities for lighting control for lighting designators and end users. In addition to CCT adjustments over a wide range, users will also be able to change the hue of white light along the CCT line as desired by the end user. For example, lumileds proprietary Luxeon ^® Fusion system, which has a wide tuning range on a single platform, is an ideal candidate for various types of color tunable applications (Lumileds Luxeon ^® The Fusion system is manufactured by Lumileds LLC, address: sitrelin Boolean 370, san Jose, calif., post code: 95131). One aspect of the artificial centered illumination is the ability to vary both the associated color temperature and intensity of light. The disclosed subject matter relates to a user-controlled design paradigm that creates a perceptually uniform color-tuning experience.

Referring now to fig. 1, a portion of an international commission on illumination (CIE) color chart 100 is shown, including a Black Body Line (BBL) 101 (also referred to as the planckian locus), which forms the basis for understanding various embodiments of the subject matter disclosed herein. BBL 101 shows the chromaticity coordinates of a black body radiator of varying temperature. It is generally recognized that in most lighting situations, the light source should have chromaticity coordinates that are located on or near the BBL 101. Various mathematical procedures are known in the art for determining the "closest" blackbody radiator. As mentioned above, such common lamp specification parameters are known as Correlated Color Temperature (CCT). D (D) _uv The values provide a useful and complementary way to further describe chromaticity, D _uv The value is that the chromaticity coordinates of the lamp lie above the BBL 101 (positive D _uv Value) or at BBL 101 (negative D) _uv A value) of the degree below.

A portion of the color chart is shown as including a number of isotherms 117. Even if each of these lines is not on BBL 101, any color point on isotherm 117 has a constant CCT. For example, the first isotherm 117A has a CCT of 10000K, the second isotherm 117B has a CCT of 5000K, the third isotherm 117C has a CCT of 3000K, and the fourth isotherm 117D has a CCT of 2200K.

With continued reference to fig. 1, cie color chart 100 also shows a number of ellipses representing Macadam ellipses (MAEs) 103, centered on BBL 101, and extending from BBL 101 by a distance of one step 105, three steps 107, five steps 109, or seven steps 111. MAEs are based on psychometric studies and define a region on the CIE chromaticity diagram that contains all colors indistinguishable to a typical observer from the colors at the center of the ellipse. Thus, each of MAE steps 105-111 (one step through seven steps) is considered to be substantially the same color for a typical observer as the color at the center of the corresponding one of MAEs 103. A series of curves 115A, 115B, 115C and 115D represent distances B BL 101 is substantially equidistant from, and D of, for example, +0.006, +0.003, 0, -0.003, and-0.006, respectively _uv The values are correlated.

Referring now to fig. 2A, with continued reference to fig. 1, fig. 2A shows a chromaticity diagram 200 having approximate chromaticity coordinates for the colors of typical coordinate values of a red (R) LED at coordinate 205, a green (G) LED at coordinate 201, and a blue (B) LED at coordinate 203, as noted on the x-y scale of chromaticity diagram 200. Fig. 2A illustrates an example of a chromaticity diagram 200 for defining a wavelength spectrum of a visible light source, according to some embodiments. Chromaticity diagram 200 of fig. 2A is but one way of defining the wavelength spectrum of a visible light source; other suitable definitions are known in the art and may also be used with the various embodiments of the disclosed subject matter described herein.

A convenient way to specify a portion of chromaticity diagram 200 is by a set of equations in the x-y plane, where each equation has a trajectory defining a solution to a line on chromaticity diagram 200. These lines may intersect to designate a particular region, as described in more detail below with reference to fig. 2B. As an alternative definition, the white light source may emit light corresponding to light from a blackbody source operating at a given color temperature.

Chromaticity diagram 200 also shows BBL 101 as described above with reference to fig. 1. Each of the three LED coordinate locations 201, 203, 205 is the CCT coordinates of a "fully saturated" LED of the respective color (green, blue, and red). However, if "white light" is created by combining a proportion of R, G and B LEDs, the CRI of such a combination will be very low. Typically, a CRI of about 90 or higher is desirable in the above-described environments (such as retail or hotel settings).

Fig. 2B shows a revised version of the chromaticity diagram 200 of fig. 2A with approximate chromaticity coordinates of the desaturated R, G and B LEDs approaching the BBL, the desaturated R, G and B LEDs having a Color Rendering Index (CRI) of about 90+ and within a defined range of color temperatures, in accordance with various embodiments of the disclosed subject matter.

However, chromaticity diagram 250 of fig. 2B shows approximate chromaticity coordinates of desaturated (soft) R, G and B LEDs near BBL 101. The coordinate values (as noted on the x-y scale of chromaticity diagram 250) are shown as a desaturated red (R) LED at coordinate 255, a desaturated green (G) LED at coordinate 253, and a desaturated blue (B) LED at coordinate 251. In various embodiments, the range of color temperatures of the desaturated R, G and B LEDs can range from about 1800K to about 2500K. In other embodiments, the desaturated R, G and B LEDs can range in color temperature from, for example, about 2700K to about 6500K. In other embodiments, the desaturated R, G and B LEDs can range in color temperature from about 1800K to about 7500K. In other embodiments, the desaturated R, G and B LEDs can be selected to be within a wide range of color temperatures. As described above, the Color Rendering Index (CRI) of the light source does not indicate the apparent color of the light source; this information is given by Correlated Color Temperature (CCT). Thus, CRI is a quantitative measure of the ability of a light source to faithfully display various object colors as compared to an ideal light source or natural light source.

In a particular exemplary embodiment, a triangle 257 formed between the desaturated R, G and each coordinate value of the B-LED is also shown. Desaturated R, G and B LEDs are formed (e.g., LEDs are formed by mixtures of phosphors and/or mixtures of materials, as known in the art) to have coordinate values near BBL 101. Accordingly, the coordinate locations of the respective desaturated R, G and B LEDs, and as delineated by triangle 257, have a CRI of about 90 or greater, and an approximately tunable color temperature range of, for example, about 2700K to about 6500K. Thus, the selection of Correlated Color Temperature (CCT) may be selected in the color adjustment applications described herein such that all combinations of the selected CCTs result in a lamp having a CRI of 90 or greater. Each of the desaturated R, G and B LEDs can include a single LED or array of LEDs (or group of LEDs), wherein each LED within the array or group has the same or similar desaturation color as the other LEDs within the array or group. The combination of one or more desaturated R, G and B LEDs comprises a lamp.

Fig. 2C shows a revised version of the chromaticity diagram 200 of fig. 2A with approximate chromaticity coordinates of the desaturated R, G and B LEDs approaching the BBL, the desaturated R, G and B LEDs having a Color Rendering Index (CRI) of about 80+ and within a defined color temperature range that is wider than the desaturated R, G and B LEDs of fig. 2B, in accordance with various embodiments of the disclosed subject matter.

However, chromaticity diagram 270 of fig. 2C shows the approximate chromaticity coordinates of the desaturated R, G and B LEDs, with the desaturated R, G and B LEDs of fig. 2C disposed farther from BBL 101 than the desaturated R, G and B LEDs of fig. 2B. The coordinate values (as noted on the x-y scale of chromaticity diagram 270) are shown as a desaturated red (R) LED at coordinate 275, a desaturated green (G) LED at coordinate 273, and a desaturated blue (B) LED at coordinate 271. In various embodiments, the range of color temperatures of the desaturated R, G and B LEDs can range from about 1800K to about 2500K. In other embodiments, the desaturated R, G and B LEDs can range in color temperature from about 2700K to about 6500K. In other embodiments, the desaturated R, G and B LEDs can range in color temperature from about 1800K to about 7500K.

In a particular exemplary embodiment, a triangle 277 formed between each coordinate value of the desaturated R, G and B LED is also shown. Desaturated R, G and B LEDs are formed (e.g., LEDs are formed by mixtures of phosphors and/or mixtures of materials, as is known in the art) to have coordinate values near BBL 101. Accordingly, the coordinate locations of the respective desaturated R, G and B LEDs, and as delineated by triangle 277, have a CRI of about 80 or greater, and an approximately tunable color temperature range of, for example, about 1800K to about 7500K. Since the color temperature range is larger than that shown in fig. 2B, CRI is reduced to about 80 or more accordingly. However, one of ordinary skill in the art will recognize that the desaturated R, G and B LEDs can be manufactured to have separate color temperatures anywhere within the chromaticity diagram. Thus, the selection of Correlated Color Temperature (CCT) may be selected in the color adjustment applications described herein such that all combinations of the selected CCTs result in a lamp having a CRI of 80 or greater. Each of the desaturated R, G and B LEDs can include a single LED or array of LEDs (or group of LEDs), wherein each LED within the array or group has the same or similar desaturation color as the other LEDs within the array or group. The combination of one or more desaturated R, G and B LEDs comprises a lamp.

Fig. 3 shows a prior art color adjustment device 300 using a hardwired flux control device 301 and a separate hardwired CCT control device 303. The flux control device 301 is coupled to a single channel driver circuit 305 and the CCT control device is coupled to a combined LED driver circuit/LED array 320. The combined LED driver circuit/LED array 320 may be a current driver circuit, a PWM driver circuit, or a hybrid current driver/PWM driver circuit. Each of the flux control device 301, CCT control device 303, and single channel driver circuit 305 are located in a customer facility 310, and all devices must typically be installed with applicable national and local regulations governing high voltage circuits. The combined LED driver circuit/LED array 320 is typically located remotely (e.g., a few meters to tens of meters or more) from the customer premises 310. Thus, both the initial purchase price and the installation price may be high (sigificant).

Thus, in a conventional color tunable system operating on a single channel constant current driver, two control inputs are typically required, one for flux control (e.g., luminous flux or dimming) and the other for color tuning. The control input may be implemented by, for example, an electromechanical device such as a linear or rotary slider, DIP switch, or standard 0V to 10V dimmer.

FIG. 4 is an exemplary embodiment of a graph 400 showing CCT values as a function of control input values and illustrating differences between two user control designs in accordance with various embodiments of the disclosed subject matter. The results of two user control designs are shown as two graphical curves. The user control device for adjusting the CCT value may be the same as or similar to CCT control device 303 of fig. 3, with appropriate modifications to the second user control design as described below.

CCT is often used to represent chromaticity of white light sources, as known to those of ordinary skill in the art. However, as described above, chromaticity is a two-dimensional value, and the other dimension (distance from the BBL) is often missing. D (D) _uv Has been defined in the American National Standards Institute (ANSI) standard. Thus, chromaticity coordinates (x, y) or (u ', v')Not intuitively carrying color information. CCT and D _uv Carrying complete color information.

Furthermore, the unit step of CCT values does not lead to a uniform perception of color. This is demonstrated in Table I below, which is taken from ANSI C78.377 (2015). The tolerance in CCT increases gradually with increasing CCT value. Thus, if the user control representing the CCT value is mapped linearly to the CCT value, the most visible change occurs during the beginning of the CCT control device range (e.g., at the beginning of the slider range) and is therefore not as linear as expected.

Referring again to fig. 4, the non-uniform mapping curve 403 maps CCT values that are uniformly spaced based on a given user control input. The user control input is related to a desired CCT value. However, the two equal intervals on the user control are not equivalent to approximately equal differences in CCT space. That is, the non-uniform mapping curve 403 is based on equal step sizes between adjacent points on the CCT control device (e.g., from a first level of 16 units, to a second level of 32 units, to a third level of 48 units, to a fourth level of 64 units, etc., where the units are arbitrary but equally spaced). However, equal step sizes result in an uneven increase in perceived CCT values.

The uniform mapping curve 401 maps selected CCT values to equidistant intervals on the user control. That is, the uniform mapping curve 401 has unequal step sizes (e.g., from a first level of 3 units, to a second level of 6 units, to a third level of 10 units, to a fourth level of 13 units, etc., where the units are arbitrary but unequal intervals) between adjacent points on the CCT control device. However, unequal step sizes result in an approximately uniform increase in perceived CCT values.

Those of ordinary skill in the art will readily recognize in fig. 4 that most points of the uniform map curve 401 are centered within about the first quarter of the curve (e.g., control input values in units of about 0 to about 340 control input values). As the control input value increases, the distance between subsequent points on the uniform mapping curve 401 increases (the distance between subsequent points on the curve is greater). Thus, when an end user changes an input control device (e.g., the CCT control device of fig. 3), the color temperature of the LED or LED array coupled to the input control changes rapidly at the lower portion of the control device, and then the color temperature of the LED or LED array changes very slowly thereafter. This non-linear situation creates a nervous and restless experience for the end user, where higher color temperatures become more and more difficult to control precisely, among other things.

Using the non-uniform mapping curve 403 enables an end user to have a smooth and visually pleasing conditioning experience. For example, when the end user moves a small distance at the beginning of, for example, a linear motion of a slider, for example, comprising a modified variation of CCT control device 303, the color temperature of the LED increases by a given amount. When the end user moves approximately the same small distance towards the end of the linear motion of the slider, the perceived color difference in the color temperature of the LED increases by approximately the same given amount as the beginning of the slider range.

In order to achieve a smooth and visually pleasing conditioning experience, in accordance with the disclosed subject matter, the following describes a method of finding appropriate slider increments and modification variants for the CCT control device of fig. 3. Thus, consider that there are N points on the CCT adjustment curve between two given CCT values. As outlined below, the N points are calculated in such a way that the color perception difference between two adjacent points is substantially uniform.

Fig. 5 illustrates an exemplary embodiment of a series of selected control points 500 substantially along the BBL 501 in accordance with various embodiments of the disclosed subject matter. The selected control points on the BBL 501 represent the points of the CCT adjustment curve described above. For example, a portion 503 of the selected control points is shown in the range of about 6500K to about 3000K. However, the selected control point need not be located on the BBL 501. For example, in various embodiments, the selected control point may be located near the BBL, such as within a selected Macadam ellipse (see fig. 1) or within a selected range of Macadam ellipses.

The end user control interface, e.g., a control device comprising, for example, a slider or dial, then has a range of movement that is linearly mapped to the calculated N points. In one embodiment, the linearly mapped range of motion is then stored in a CCT control device (e.g., into a storage area such as memory and/or a storage area programmed in software, hardware, or firmware). In another embodiment, the range of movement of the linear map may alternatively be stored in, for example, a remote control box or within an LED array (e.g., into a storage area such as a memory and/or a storage area programmed in software, hardware, or firmware). In both embodiments, the storage device is electrically coupled to the CCT control device, either internally or externally, to correlate mechanical movement of the CCT control device to provide a substantially uniform increase in perceived CCT value from one or more LEDs or LED arrays. In either case, the calculated N CCT points may be generated, for example, in CIE 1976 space. The CIE 1976 color space is considered to be a perceptually uniform color space. The same Euclidean distance in this space is considered perceptually uniform.

Referring now to fig. 6, an exemplary method process flow diagram 600 for determining control equipment points of a CCT adjustment curve is shown. In an exemplary embodiment, the calculation begins at operation 601 by selecting a starting point of a CCT adjustment curve (e.g., color temperature on the BBL line). In operation 603, consider a subsequent point of the CCT adjustment curve that is approximately equal to the desired distance d in u 'v' space. At operation 605, the exemplary method moves to the last determined point and determines another subsequent point in u 'v' space that is also approximately equal to the desired distance d. At operation 607, the exemplary method is repeated until N points are obtained or the adjustment range is exhausted.

To find a point at a fixed distance (e.g., a desired or predetermined distance), a intercept point may be calculated analytically between the CCT adjustment curve in u 'v' color space and a circle of radius d (see, e.g., fig. 5). Alternatively, the CCT adjustment curve may be converted to u 'v' coordinates with a sufficiently high resolution and then traversing all points on the CCT adjustment curve.

All points (including the first point) that match or approximate the match criteria are then put into the list as output for use in user control (e.g., CCT control device). Thus, after obtaining N points, the movement range of the user control is linearly mapped to the N points in operation 609. For example, if the movement range of the user control is 256 discrete steps and the number of points N is 64, intervals each equal to 4 are allocated to the CCT value according to the determined values of the N points.

In an exemplary embodiment, the algorithm for converting the CCT to linear or substantially linear includes, for example, starting from an initial point, determining a next point at a specified distance. When the next point at the specified distance is found, the algorithm proceeds to the point just found and then determines the next point at the specified distance. All points (including the first point) that match the criteria are then put into a list as output.

Thus, as described above with reference to fig. 5 and 6, the algorithm generates points on the BBL. The same principle can be applied to other desired curve types as well. In one specific exemplary embodiment, the algorithm for linearizing the CCT transition may be expressed as follows:

those of ordinary skill in the art will recognize additional algorithms that may be used to give the same or similar results upon reading and understanding the disclosed subject matter. Additionally, those skilled in the art will recognize that similar types of algorithms may be encoded in software, firmware, or implemented in various types of hardware devices such as Application Specific Integrated Circuits (ASICs) or special purpose processors or control devices. The results from the algorithm (the list of outputs described above) may then be added to the control device (e.g., added to the CCT control device, saved as software within the control device to associate the movement of the device with the desired CCT value, hard coded into the control device to associate the movement of the device with the desired CCT value, implemented into an ASIC within the control device to associate the movement of the device with the desired CCT value, implemented into a processor or other type of hardware (e.g., field Programmable Gate Array (FPGA) within the control device) to associate the movement of the device with the desired CCT value, or by other means known in the art and described in more detail below with reference to fig. 7).

Machine with instructions to perform various operations

Fig. 7 is a block diagram illustrating components of a machine 700 capable of reading instructions from a machine-readable medium (e.g., a non-transitory machine-readable medium, a machine-readable storage medium, a computer-readable storage medium, or any suitable combination thereof) and performing any one or more of the methodologies discussed herein, according to some embodiments. In particular, FIG. 7 shows a diagrammatic representation of machine 700 in the example form of a computer system, and within this machine 700, instructions 724 (e.g., software, programs, applications, applets, apps, or other executable code) for causing the machine 700 to perform any one or more of the methodologies discussed herein (e.g., process recipes) may be executed.

In alternative embodiments, machine 700 operates as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the machine 700 may operate in the capacity of a server machine or a client machine in server-client network environments, or as a peer machine in point-to-point (or distributed) network environments. Machine 700 may be a server computer, a client computer, a Personal Computer (PC), a tablet computer, a laptop computer, a netbook, a set-top box (STB), a Personal Digital Assistant (PDA), a cellular telephone, a smart phone, a network appliance, a network router, a network switch, a bridge, or any machine capable of executing instructions 724 sequentially or otherwise, the instructions 724 specifying actions to be taken by the machine. Furthermore, while only a single machine is illustrated, the term "machine" shall also be taken to include a collection of machines that individually or jointly execute instructions 724 to perform any one or more of the methodologies discussed herein.

Machine 700 includes a processor 702 (e.g., a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Radio Frequency Integrated Circuit (RFIC), or any suitable combination thereof), a main memory 704, and a static memory 706, which communicate with each other via a bus 708. The processor 702 may contain microcircuits that are temporarily or permanently configurable by some or all of the instructions 724, such that the processor 702 may be configured to perform any one or more of the methods described herein, in whole or in part. For example, a set of one or more microcircuits of the processor 702 may be configurable to execute one or more modules (e.g., software modules) described herein.

The machine 700 may further include a graphics display 710 (e.g., a Plasma Display Panel (PDP), a Light Emitting Diode (LED) display, a Liquid Crystal Display (LCD), a projector, or a Cathode Ray Tube (CRT)). The machine 700 may also include an alpha-numeric input device 712 (e.g., a keyboard), a cursor control device 714 (e.g., a mouse, touchpad, trackball, joystick, motion sensor, or other pointing tool), a storage unit 716, a signal generation device 718 (e.g., a speaker), and a network interface device 720.

The storage unit 716 includes a machine-readable medium 722 (e.g., a tangible and/or non-transitory machine-readable storage medium) having stored thereon instructions 724 embodying any one or more of the methods or functions described herein. The instructions 724 may also reside, completely or at least partially, within the main memory 704, within the processor 702 (e.g., within the processor's cache memory), or both, during execution thereof by the machine 700. Accordingly, main memory 704 and processor 702 may be considered machine-readable media (e.g., tangible and/or non-transitory machine-readable media). The instructions 724 may be transmitted or received over a network 726 via the network interface device 720. For example, the network interface device 720 may communicate the instructions 724 using any one or more transport protocols (e.g., hypertext transfer protocol (HTTP)).

In some embodiments, machine 700 may be a portable computing device, such as a smartphone or tablet, and have one or more additional input components (e.g., sensors or gauges). Examples of such additional input components include an image input component (e.g., one or more cameras), an audio input component (e.g., a microphone), a direction input component (e.g., a compass), a position input component (e.g., a Global Positioning System (GPS) receiver), an orientation component (e.g., a gyroscope), a motion detection component (e.g., one or more accelerometers), a height detection component (e.g., an altimeter), and a gas detection component (e.g., a gas sensor). The inputs obtained by any one or more of these input components may be accessible and available for use by any of the modules described herein.

The term "memory" as used herein refers to a machine readable medium capable of temporarily or permanently storing data and is understood to include, but not be limited to, random Access Memory (RAM), read Only Memory (ROM), cache memory, flash memory, and cache memory. While the machine-readable medium 722 is shown in an embodiment to be a single medium, the term "machine-readable medium" should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, or associated caches and servers) that are capable of storing the instructions. The term "machine-readable medium" shall also be taken to include any medium, or combination of multiple media, that is capable of storing instructions for execution by a machine (e.g., machine 700), such that the instructions, when executed by one or more processors of the machine (e.g., processor 702), cause the machine to perform any one or more of the methodologies described herein. Thus, a "machine-readable medium" refers to a single storage device or apparatus, as well as a "cloud-based" storage system or storage network that includes multiple storage devices or apparatus. Thus, the term "machine-readable medium" shall be taken to include, but not be limited to, one or more tangible (e.g., non-transitory) data repositories in the form of solid-state memory, optical media, magnetic media, or any suitable combination thereof.

Further, the machine-readable medium is non-transitory in that it does not embody a propagated signal. However, marking a tangible machine-readable medium as "non-transitory" should not be construed to mean that the medium is not capable of moving: the medium should be considered transportable from one physical location to another. Additionally, because the machine-readable medium is tangible, the medium may be considered a machine-readable device.

The instructions 724 may further be transmitted or received over a network 726 (e.g., a communication network), the network 726 using a transmission medium via a network interface device 720 and utilizing any one of a number of well-known transmission protocols (e.g., HTTP). Examples of communication networks include a Local Area Network (LAN), a Wide Area Network (WAN), the internet, a mobile telephone network, a POTS network, and wireless data networks (e.g., wiFi and WiMAX networks). The term "transmission medium" shall be taken to include any intangible medium that is capable of storing, encoding or carrying instructions for execution by the machine, and includes digital or analog communications signals or other intangible medium to facilitate communication of such software.

In some example embodiments, the hardware modules may be implemented, for example, mechanically or electronically, or by any suitable combination thereof. For example, a hardware module may include specialized circuitry or logic permanently configured to perform certain operations. The hardware module may be or include a special purpose processor such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC). A hardware module may also include programmable logic or circuitry that is temporarily configured by software to perform certain operations. By way of example, the hardware modules may include software embodied within a Central Processing Unit (CPU) or other programmable processor. It will be appreciated that decisions of hardware modules may be driven by cost and time considerations, mechanically, electrically, in dedicated and permanently configured circuits, or in circuits that are temporarily configured (e.g., configured by software).

In various embodiments, many of the described components may include one or more modules for performing the functions disclosed herein. In some embodiments, the modules may constitute software modules (e.g., code stored on a machine-readable medium or on a transmission medium, or code otherwise embodied in a machine-readable medium or in a transmission medium), hardware modules, or any suitable combination thereof. A "hardware module" is a tangible (e.g., non-transitory) physical component (e.g., a set of one or more microprocessors or other hardware-based devices) capable of performing certain operations and interpreting certain signals. One or more modules may be configured or arranged in some physical manner. In various embodiments, one or more microprocessors or one or more hardware modules thereof may be configured by software (e.g., an application or a portion thereof) as a hardware module that operates to perform the operations described herein for the module.

In some example embodiments, the hardware modules may be implemented, for example, mechanically or electronically, or by any suitable combination thereof. For example, a hardware module may include specialized circuitry or logic permanently configured to perform certain operations. As described above, the hardware modules may include or contain a dedicated processor, such as an FPGA or ASIC. The hardware module may also include programmable logic or circuitry temporarily configured by software to perform certain operations, such as linearly mapping the calculated range of movement of the N points on the color adjustment device (see, e.g., fig. 5 and 6).

The above description includes illustrative examples, devices, systems, and methods embodying the disclosed subject matter. In the description, for purposes of explanation, numerous specific details are set forth in order to provide an understanding of various embodiments of the disclosed subject matter. It will be apparent, however, to one of ordinary skill in the art that the various embodiments of the present subject matter may be practiced without these specific details. In other instances, well-known structures, materials, and techniques have not been shown in detail in order not to obscure the various embodiments shown.

As used herein, the term "or" may be interpreted as an inclusive or exclusive meaning. Furthermore, other embodiments will be apparent to those of ordinary skill in the art upon reading and understanding the disclosure provided. Furthermore, those of ordinary skill in the art will readily appreciate, upon reading and understanding the disclosure provided herein, that various combinations of the techniques and examples provided herein may be applied in a variety of combinations.

While various embodiments are discussed separately, these separate embodiments are not intended to be considered stand-alone techniques or designs. As indicated above, each of the various sections may be interrelated and each may be used alone or in combination with other types of electrical control devices, such as dimmers and related devices. Thus, although various embodiments of the methods, operations, and processes have been described, the methods, operations, and processes may be used alone or in various combinations.

Accordingly, many modifications and variations will be apparent to those of ordinary skill in the art upon reading and understanding the disclosure provided herein. Functionally equivalent methods and apparatus within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing description. Portions and features of some embodiments may be included in, or substituted for, those of others. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is therefore to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

The Abstract of the disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. The commit proposal is based on the following understanding: it is not intended to interpret or limit the claims. In addition, in the foregoing detailed description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure should not be interpreted as limiting the claims. Thus the following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.

Claims (24)

1. A control device for color adjustment of an array of Light Emitting Diodes (LEDs) for perceptually uniform color adjustment, the device comprising:

a Correlated Color Temperature (CCT) control device configured to be adjusted by an end user to a desired color temperature of the LED array, the CCT control device further configured to generate an output signal corresponding to the desired color temperature; and

a storage device electrically coupled to the CCT control device and configured to store and control correlations between mechanical ranges of movement of the CCT control device to provide a substantially uniform increase in a plurality of perceived CCT values from the LED array based on a set of N predetermined values based on a number of discrete steps in the mechanical range of movement of the CCT control device and calculated such that a color perception difference between two adjacent ones of the N points will produce a color perception difference to a person that is substantially uniform and linear with respect to an increasing CCT increase, the storage device further configured to map selected CCT values to substantially equidistant intervals on the CCT control device to produce a substantially uniformly mapped curve having unequal step distances between adjacent ones of the N predetermined values.

2. The control apparatus of claim 1, wherein the set of N predetermined values is determined as points on a CCT adjustment curve between two given CCT values, the set of N predetermined values being calculated such that a color perception difference between two adjacent points is substantially uniform, wherein the unequal step distance is selected to reduce non-uniform variation of the perceived CCT values as a level of the CCT control device changes.

3. The control device of claim 1, wherein the set of N predetermined values is determined to be located substantially along a Black Body Line (BBL).

4. The control device of claim 1, wherein the set of N predetermined values is determined to be substantially located near a Black Body Line (BBL).

5. The control device of claim 4, wherein the set of N predetermined values is determined to lie substantially near a Black Body Line (BBL) and within a selected Macadam ellipse.

6. The control device of claim 4, wherein the set of N predetermined values is determined to lie substantially near a Black Body Line (BBL) and within a selected range of Macadam ellipses.

7. The control device of claim 1, wherein the LED array comprises at least one LED for each of three selected colors of light in the visible portion of the spectrum.

8. The control device of claim 1, wherein the LED array is a multicolor array comprising a plurality of LEDs of different colors.

9. The control device of claim 7, wherein the colors of the LEDs in the LED multicolor array include at least one red LED, at least one green LED, and at least one blue LED.

10. The control device of claim 7, wherein the LED multicolor array comprises at least one desaturated red LED, at least one desaturated green LED, and at least one desaturated blue LED.

11. The control apparatus of claim 1, wherein the CCT control device comprises a 0 volt to 10 volt dimmer device.

12. A controllable lighting device, comprising:

an LED array having at least one desaturated red LED, at least one desaturated green LED, and at least one desaturated blue LED; and

a control device comprising:

a Correlated Color Temperature (CCT) control device configured to be adjusted by an end user to a desired color temperature of the LED array, the CCT control device further configured to generate an output signal corresponding to the desired color temperature, and

a storage device electrically coupled to the CCT control device and configured to store and control a correlation between a range of mechanical movement of the CCT control device to provide a substantially uniform increase in perceived CCT values from the LED array based on a set of N predetermined values calculated such that a color perception difference between two adjacent ones of the N points will produce a color perception difference to a person that is substantially uniform and linear with respect to increasing CCT increases, the storage device further configured to map selected CCT values to substantially equidistant intervals on the CCT control device to produce a substantially uniformly mapped curve having unequal step distances between adjacent ones of the N predetermined values.

13. The controllable lighting arrangement according to claim 12, wherein a set of N predetermined values of the control arrangement is determined as points on a CCT adjustment curve between two given CCT values, the set of N predetermined values being calculated such that the color perceived difference between two adjacent points is substantially uniform, wherein the unequal step distance is selected to reduce non-uniform variations of the perceived CCT values as the level of the CCT control device changes.

14. The controllable lighting device of claim 12, wherein the LED array with the at least one desaturated red LED, the at least one desaturated green LED, and the at least one desaturated blue LED is configured to have a color temperature range of from about 2700K to about 6500K.

15. The controllable lighting device according to claim 12, wherein the set of N predetermined values of the control device is determined to be located substantially along the Black Body Line (BBL).

16. The controllable lighting device according to claim 12, wherein the set of N predetermined values of the control device is determined to lie substantially near the Black Body Line (BBL) and within a selected range of Macadam ellipses.

17. A method for determining a control device point of a Correlated Color Temperature (CCT) adjustment curve, the method comprising: selecting a starting point of the CCT adjustment curve;

Determining a subsequent point of the CCT adjustment curve in u 'v' space approximately equal to a predetermined distance d;

determining additional subsequent points of the CCT adjustment curve in the u 'v' space approximately equal to another predetermined distance d from the last determined points; and

determining a set of N predetermined values comprising the determined points, the N predetermined values being calculated such that a color perception difference between two adjacent ones of the N points produces a color perception difference to a person, the color perception difference increasing substantially uniformly and linearly with respect to an increasing CCT, the set of N predetermined values being further determined to map selected CCT values to substantially equidistant intervals on a CCT control device to produce a substantially uniformly mapped curve having unequal step distances between adjacent ones of the N predetermined values.

18. The method for determining a control device point of a CCT adjustment curve according to claim 17, wherein the starting point is selected to be on a Black Body Line (BBL).

19. The method for determining a control device point of a CCT adjustment curve according to claim 17, wherein the starting point is selected to be substantially near a Black Body Line (BBL) and within a selected Macadam ellipse.

20. The method for determining control equipment points of a CCT adjustment curve according to claim 17, further comprising repeating the determining step until a range of movement is obtained up to one or more stopping points, the stopping points comprising obtaining the set of N predetermined values and a run-out adjustment range.

21. The method for determining control device points of a CCT adjustment curve according to claim 17, wherein determining a point at a predetermined distance d comprises analytically calculating a intercept point between the CCT adjustment curve and a circle of radius d in the u 'v' color space.

22. The method for determining control device points of a CCT adjustment curve according to claim 17, wherein determining a point at a predetermined distance d further comprises:

converting the CCT adjustment curve into u 'v' coordinates; and

all points on the CCT adjustment curve are then traversed.

23. The method for determining control device points of a CCT adjustment curve according to claim 17, further comprising storing all determined points into a list as output to be used in the CCT control device, the all determined points including a first selected starting point.

24. The method for determining control device points of a CCT adjustment curve according to claim 23, further comprising linearly mapping a range of motion of the CCT control device to the all determined points.