CN115720727A - Control design for perceptually uniform color adjustment - Google Patents

Abstract

Various embodiments include apparatus and methods for controlling an apparatus to color adjust a Light Emitting Diode (LED) array. In one particular example, a control apparatus for color adjustment of a Light Emitting Diode (LED) array for perceptually uniform color adjustment is disclosed. The apparatus includes a Correlated Color Temperature (CCT) control device that is adjustable by an end user to a desired color temperature of an array of LEDs and produces 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 a 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 requirement

This application claims the benefit of priority of european patent application No. 19207130.6, entitled "perceptually uniform color-tuned control design", filed on 5.11.2019, and the benefit of priority of U.S. utility patent application No. 16/528108, filed on 31.7.2019, and entitled "perceptually uniform color-tuned control design", each of which is incorporated herein by reference in its entirety.

Technical Field

The subject matter disclosed herein relates to color tuning of one or more Light Emitting Diodes (LEDs) or LED arrays including 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 control design methods and apparatus to create a perceptually uniform color adjustment experience for one or more LEDs or LED arrays.

Background

Light Emitting Diodes (LEDs) are commonly used in a variety of 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, the 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 an LED and the distance of the temperature of the LED on the CCT from the black body line (BBL, also known as the black body locus or planckian locus) can affect human perception of an object.

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

The information described in this section is provided to provide the skilled person with background to the following disclosed subject matter and should not be taken as an admission of prior art.

Drawings

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

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

FIG. 2B illustrates a revised variation of the chromaticity diagram of FIG. 2A, with approximate chromaticity coordinates of desaturated R, G and B LEDs near the BBL, with 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 variation of the chromaticity diagram of fig. 2A, with approximate chromaticity coordinates of desaturated R, G and B LEDs close to the BBL, desaturated R, G and B LEDs having a Color Rendering Index (CRI) of about 80+ and within a wider defined range of color temperatures than 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 adjusting device requiring a hardwired flux control device and a separate hardwired CCT control device;

FIG. 4 is an exemplary embodiment of a chart showing CCT values as a function of control input values and illustrating the differences between two user control designs according to 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 for 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 methodologies and operations discussed herein (e.g., CCT next step 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 as illustrated in the various drawings in the attached 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 means of controlling those embodiments will be described more fully hereinafter with reference to the accompanying drawings. These examples are not mutually exclusive and features found in one example may be combined with features found in one or more other examples to achieve further embodiments. Accordingly, it will be understood that the examples shown in the accompanying drawings are provided for illustrative purposes only, and they 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. 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" can 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 intermediate 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 area's relationship to another element, region, or area as illustrated in the various figures. Those of ordinary skill in the art will understand that such 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 the particular application.

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 (referred to herein simply as "LEDs") and the like. Due to their compact size and low power requirements, LEDs may be attractive candidates for many different applications. 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, horticulture lighting, street lighting, video lights (torch for video), general lighting (e.g., home, shop, office and studio lighting, theater/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 less bright light than an incandescent light source, and thus, a multi-junction device or an array of LEDs (such as a monolithic array of LEDs, a micro-LED array, etc.) may be used in applications where enhanced brightness is desired or required.

Various types of lighting in LED-based lamps (or related lighting devices) for illuminating objects and for general lightingIn the environment, it may be desirable to control aspects of the color temperature of multiple LED-based lamps (or a single LED-based lamp) in addition to the relative brightness (e.g., luminous flux) of the lamp. Such environments may include, for example, retail locations as well as hotel locations, such as restaurants and the like. In addition to CCT, another lamp metric is the Color Rendering Index (CRI) of the lamp. The CRI is defined by the commission internationale de l' eclairage (CIE), and provides a quantitative measure of the ability of any light source, including LEDs, to accurately represent the colors of various objects, as compared to an ideal or natural light source. The highest possible CRI value is 100. Another quantitative light metric is D _uv 。D _uv Is a metric, for example defined in CIE 1960, for representing the distance of a color point to 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 dots above the BBL appear light green in color and the color dots below the BBL appear light pink in color. The disclosed subject matter provides a method for controlling color temperature (CCT and D) with a smooth and visually pleasing tuning experience _uv ) The apparatus of (1). CCT and D in color temperature and color adjustment applications, as described herein _uv Both are related.

As is known in the related art, the forward voltage of a direct color LED decreases as the dominant wavelength increases. For example, a multi-channel DC-to-DC converter may be used to drive the LEDs. 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) can 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 apparatus described herein is compatible with single channel constant current drivers to facilitate market adoption.

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

In general, color adjustment is an integral part of human-centered lighting. Advanced LED-based systems, such as desaturated RGB LED methods and related control techniques, offer new possibilities for lighting control for lighting designators and end-users. In addition to CCT adjustment over a wide range, users will also be able to vary the hue of white light along the equal CCT line according to end user preferences. For example, lumileds! proprietary Luxeon ^® The Fusion System, which has a wide range of modulation on a single platform, is an ideal candidate for various types of color tunable applications (Lumileds Luxeon ™) ^® Fusion system manufactured by Lumileds LLC, address: west telnbull, san jose, ca, usa, zip code: 95131). One aspect of human-centered illumination is the ability to simultaneously vary the relative color temperature and light intensity. The disclosed subject matter relates to a user-controlled design paradigm that creates a perceptually uniform color adjustment experience.

Referring now to fig. 1, a portion of a commission international illumination (CIE) color chart 100 is shown, including a Black Body Line (BBL) 101 (also known 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 at varying temperatures. It is generally recognized that in most lighting situations, the light source should have chromaticity coordinates located on or near the BBL 101. Various mathematical procedures are known in the art for determining the "closest" black body radiator. As mentioned above, this common lamp specification parameter is referred to as Correlated Color Temperature (CCT). D _uv The value provides a useful and complementary way of further describing the chromaticity, D _uv The value is that the chromaticity coordinate of the lamp is above the BBL 101 (positive D) _uv Value) or at BBL 101 (negative D) _uv Value) below.

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

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

Referring now to fig. 2A, and with continued reference to fig. 1, fig. 2A shows a chromaticity diagram 200 having approximate chromaticity coordinates for the colors of the typical coordinate values (as noted on the x-y scale of chromaticity diagram 200) for red (R) LEDs at coordinates 205, green (G) LEDs at coordinates 201, and blue (B) LEDs at coordinates 203. Fig. 2A illustrates an example of a chromaticity diagram 200 for defining a wavelength spectrum of a visible light source, according to some embodiments. The 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 various embodiments of the disclosed subject matter described herein.

A convenient way to specify a portion of the chromaticity diagram 200 is through a set of equations in the x-y plane, where each equation has a trajectory that defines a solution to a line on the chromaticity diagram 200. These lines may intersect to designate a particular region, as described in more detail below with reference to FIG. 2B. Alternatively defined, a white light source may emit light corresponding to light from a black body source operating at a given color temperature.

The chromaticity diagram 200 also shows the BBL 101 as described above with reference to fig. 1. Each of the three LED coordinate positions 201, 203, 205 is the CCT coordinate 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, in the environments described above (such as retail or hotel settings), a CRI of about 90 or higher is desirable.

Fig. 2B illustrates a revised variation of the chromaticity diagram 200 of fig. 2A, with approximately chromaticity coordinates of desaturated R, G and B LEDs close to the BBL, with 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, the chromaticity diagram 250 of fig. 2B shows the approximate chromaticity coordinates of desaturated (softened) R, G and B LEDs that are close to BBL 101. The coordinate values (as noted on the x-y scale of chromaticity diagram 250) are shown as desaturated red (R) LEDs at coordinates 255, desaturated green (G) LEDs at coordinates 253, and desaturated blue (B) LEDs at coordinates 251. In various embodiments, the color temperature range of desaturated R, G and B LEDs may range from about 1800K to about 2500K. In other embodiments, the desaturated R, G and B LEDs may be in a color temperature range of, for example, about 2700K to about 6500K. In other embodiments, the desaturated R, G and B LEDs may be in the color temperature range of about 1800K to about 7500K. In other embodiments, the desaturated R, G and B LEDs may be selected to be within a wide range of color temperatures. As described above, the Color Rendering Index (CRI) of a light source is not indicative of the apparent color of the light source; this information is given by the Correlated Color Temperature (CCT). Thus, the CRI is a quantitative measure of the ability of a light source to faithfully represent the color of various objects compared to an ideal or natural light source.

In a particular exemplary embodiment, a triangle 257 is also shown formed between the desaturated R, G and each coordinate value of the B LED. The desaturated R, G and B LEDs are formed (e.g., LEDs are formed by a mixture of phosphors and/or a mixture of materials as known in the art) to have coordinate values close to the BBL 101. Thus, 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 approximate tunable color temperature range of, for example, about 2700K to about 6500K. Thus, selection of a Correlated Color Temperature (CCT) may be selected in the color tuning applications described herein such that all combinations of selected CCTs result in a lamp having a CRI of 90 or greater. Each of the desaturated R, G and B LEDs may comprise a single LED or an array (or group) of LEDs, where 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 variation of the chromaticity diagram 200 of fig. 2A, with approximate chromaticity coordinates of desaturated R, G and B LEDs close to the BBL, desaturated R, G and B LEDs having a Color Rendering Index (CRI) of about 80+ and within a wider defined range of color temperatures than desaturated R, G and B LEDs of fig. 2B, in accordance with various embodiments of the disclosed subject matter.

However, the chromaticity diagram 270 of fig. 2C shows the approximate chromaticity coordinates of desaturated R, G and B LEDs, with the desaturated R, G and B LEDs of fig. 2C disposed further away from the 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 color temperature range of desaturated R, G and B LEDs may range from about 1800K to about 2500K. In other embodiments, the desaturated R, G and B LEDs may be in a color temperature range of about 2700K to about 6500K. In other embodiments, the desaturated R, G and B LEDs may be in the color temperature range of about 1800K to about 7500K.

In a specific exemplary embodiment, a triangle 277 formed between the desaturated R, G and each coordinate value of the B LED is also shown. The desaturated R, G and B LEDs are formed (e.g., LEDs are formed by a mixture of phosphors and/or a mixture of materials as known in the art) to have coordinate values close to the BBL 101. Thus, 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 approximate tunable color temperature range of, for example, about 1800K to about 7500K. Since the range of color temperatures is greater than that shown in fig. 2B, the CRI is accordingly reduced to about 80 or more. However, one of ordinary skill in the art will recognize that the desaturated R, G and B LEDs can be fabricated to have separate color temperatures anywhere within the chromaticity diagram. Thus, selection of a Correlated Color Temperature (CCT) may be selected in the color tuning applications described herein such that all combinations of selected CCTs result in a lamp having a CRI of 80 or greater. Each of the desaturated R, G and B LEDs may comprise a single LED or an array (or group) of LEDs, where 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 adjusting 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 drive 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 away (e.g., a few meters to tens of meters or more) from the customer facility 310. Therefore, both the initial purchase price and the installation price may be high (significant).

Thus, in conventional color tunable systems operating on single channel constant current drivers, 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 slider or a rotary slider, a DIP switch, or a 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 the differences between two user control designs according to various embodiments of the disclosed subject matter. The results of the two user-controlled designs are shown as two graphical curves. The user control device used to adjust the CCT value may be the same as or similar to the CCT control device 303 of fig. 3, with appropriate modifications to the second user control design as described below.

As known to those of ordinary skill in the art, CCT is often used to represent the chromaticity of a white light source. However, as described above, chroma is a two-dimensional value, and the other dimension (distance from the BBL) is often missing. D _uv Has been defined in American National Standards Institute (ANSI) standards. Therefore, these two numbers of chromaticity coordinates (x, y) or (u ', v') do not intuitively carry color information. CCT and D _uv Carrying complete color information.

Furthermore, unit steps of CCT values do not result in a uniform perception of color. This is demonstrated in table I, taken from ANSI C78.377 (2015). The tolerance in CCT increases gradually as the CCT value increases. Thus, if the user controls representing CCT values are linearly mapped to CCT values, the most visible changes occur during the beginning of the CCT control device range (e.g., at the beginning of the slider range) and are therefore not as linear as expected.

Referring again to fig. 4, 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, two equal intervals on the user control are not equivalent to an approximately equal difference in CCT space. That is, the non-uniform mapping curve 403 is based on equal steps 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 arbitrarily but equally spaced). However, equal step sizes result in an uneven increase in perceived CCT value.

The uniform mapping curve 401 maps the 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 at 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.

One of ordinary skill in the art will readily recognize in fig. 4 that most of the points of the uniform mapping 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 a 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 stressful experience for the end user, where higher color temperatures, in particular, become more and more difficult to control accurately.

Utilizing non-uniform mapping curve 403 enables the end user to have a smooth and visually pleasing adjustment 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, including a modified variant of the 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 toward the end of the linear motion of the slider, the perceived color difference in LED color temperature increases by approximately the same given amount as the beginning of the slider range.

To achieve a smooth and visually pleasing adjustment experience, a method of finding the appropriate slider increments and modification variants of the CCT control device of fig. 3 is described below, in accordance with the disclosed subject matter. 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 according to various embodiments of the disclosed subject matter. The selected control points on the BBL 501 represent 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 the Macadam ellipse.

The end user control interface, e.g., including a control device such as 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 the CCT control device (e.g., into a storage area such as memory and/or programmed in software, hardware, or firmware). In another embodiment, the linear mapped range of movement may instead be stored, for example, in a remote control box or within an LED array (e.g., into a storage area such as memory and/or programmed in software, hardware, or firmware). In both embodiments, the storage device is electrically coupled to the CCT control device internally or externally to correlate mechanical movement of the CCT control device to provide a substantially uniform increase in the 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 is considered perceptually uniform in this space.

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

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

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

In an exemplary embodiment, the algorithm for transitioning 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 that match the criteria (including the first point) are then put into a list as output.

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

one of ordinary skill in the art will recognize, upon reading and understanding the disclosed subject matter, additional algorithms that may be used to give the same or similar results. 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 output list described above) may then be added to the control device (e.g., added to a CCT control device, saved as software within the control device to associate the movement of the device with a desired CCT value, hard coded into the control device to associate the movement of the device with a desired CCT value, implemented into an ASIC within the control device to associate the movement of the device with a desired CCT value, implemented into a processor or other type of hardware (e.g., a Field Programmable Gate Array (FPGA) within the control device) to associate the movement of the device with a 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, in accordance with some embodiments. In particular, fig. 7 shows a diagrammatic representation of a machine 700 in the example form of a computer system and within which instructions 724 (e.g., software, a program, an application, an applet, an app, or other executable code) may be executed for causing the machine 700 to perform any one or more of the methodologies discussed herein (e.g., a process recipe).

In alternative embodiments, the 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 environment, or as a peer machine in a point-to-point (or distributed) network environment. The 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 web appliance, a network router, a network switch, a network bridge, or any machine capable of executing instructions 724 that specify actions to be taken by that machine. Further, 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 the instructions 724 to perform any one or more of the methodologies discussed herein.

The 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 include microcircuits that are configurable, either temporarily or permanently, by some or all of the instructions 724 such that the processor 702 may be configured to perform, in whole or in part, any one or more of the methods described herein. 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) on which are stored instructions 724 embodying any one or more of the methodologies 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, the main memory 704 and the 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 transfer protocols (e.g., hypertext transfer protocol (HTTP)).

In some embodiments, the 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 meters). 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 directional input component (e.g., a compass), a location 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), an altitude detection component (e.g., an altimeter), and a gas detection component (e.g., a gas sensor). The input 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 storing data either temporarily or permanently, and can be understood to include, but is not 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 the 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, "machine-readable medium" refers to a single storage apparatus or device, as well as a "cloud-based" storage system or storage network that includes multiple storage apparatuses or devices. The term "machine-readable medium" shall accordingly be taken to include, but not be limited to, one or more tangible (e.g., non-transitory) data repositories in the form of a solid-state memory, an optical medium, a magnetic medium, or any suitable combination thereof.

Further, a machine-readable medium is non-transitory in that it does not embody a propagated signal. However, labeling 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 a 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 communications network) using a transmission medium via the network interface device 720 and utilizing any of a number of well-known transfer protocols (e.g., HTTP). Examples of communication networks include a Local Area Network (LAN), a Wide Area Network (WAN), the internet, a mobile phone network, a POTS network, and a wireless data network (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 comprise dedicated circuitry or logic that is 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 comprise programmable logic or circuitry that is temporarily configured by software to perform certain operations. As an example, a hardware module may include software that is encompassed within a Central Processing Unit (CPU) or other programmable processor. It will be appreciated that the decision to implement a hardware module mechanically, electrically, in a dedicated and permanently configured circuit, or in a temporarily configured (e.g., configured by software) circuit may be driven by cost and time considerations.

In various embodiments, many of the described components may include one or more modules for implementing the functionality disclosed herein. In some embodiments, the modules may constitute software modules (e.g., code stored on or otherwise embodied in a machine-readable medium or transmission medium), hardware modules, or any suitable combination thereof. A "hardware module" is a tangible (e.g., non-transitory) physical component (e.g., a collection of one or more microprocessors or other hardware-based devices) that is 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 program or portion thereof) as a hardware module that operates to perform the operations described herein for that 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 comprise dedicated circuitry or logic that is permanently configured to perform certain operations. As mentioned above, the hardware module may comprise or contain a dedicated processor, such as an FPGA or an ASIC. The hardware module may also include programmable logic or circuitry that is temporarily configured by software to perform certain operations, such as linearly mapping to a calculated range of movement of 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 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 illustrated embodiments.

As used herein, the term "or" may be interpreted in an inclusive or exclusive sense. Moreover, other embodiments will be understood by those of ordinary skill in the art upon reading and understanding the provided disclosure. Further, upon reading and understanding the disclosure provided herein, one of ordinary skill in the art will readily appreciate that various combinations of the techniques and examples provided herein may be applied in various combinations.

While various embodiments are discussed separately, these separate embodiments are not intended to be considered independent techniques or designs. As indicated above, each of the various portions 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, while various embodiments of methods, operations, and processes have been described, these methods, operations, and processes may be used alone or in various combinations.

Thus, many modifications and variations will be apparent to practitioners skilled in the art upon reading and understanding the disclosure provided herein. Functionally equivalent methods and apparatuses 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. Accordingly, the disclosure is 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 digest is submitted 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 may be grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to 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 a Light Emitting Diode (LED) array for perceptually uniform color adjustment, the device comprising:

a Correlated Color Temperature (CCT) control device configured to be adjusted to a desired color temperature of an LED array by an end user, the CCT control device further configured to produce 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 a plurality of 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 human that is substantially uniform and linear with respect to an increasing CCT increase.

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.

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 near a Black Body Line (BBL).

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

7. The control device of claim 1, wherein the array of LEDs 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 multi-color array comprising a plurality of differently colored LEDs.

9. The control device of claim 7, wherein the colors of the LEDs in the multicolored array of LEDs 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 multicolored array of LEDs 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 0-10 volt dimmer device.

12. A controllable lighting device, comprising:

an array of LEDs 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 to a desired color temperature of an LED array by an end user, the CCT control device further configured to produce an output signal corresponding to the desired color temperature; and

a storage device 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 a plurality of 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 human, the color perception difference being substantially uniform and linear with respect to an increasing CCT increase.

13. The controllable lighting device of claim 12, 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.

14. The controllable lighting device of claim 15, 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 from about 2700K to about 6500K.

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

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

17. A method for determining a control device point for a Correlated Color Temperature (CCT) tuning curve, the method comprising:

selecting a starting point of a CCT (continuous casting temperature) adjusting curve;

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

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

determining a set of N predetermined values comprising the determined points, the N predetermined values calculated such that a color perception difference between two adjacent ones of the N points produces a color perception difference to the person that is substantially uniform and linear with respect to an increasing CCT.

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

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

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

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

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

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

all points on the CCT adjustment curve are then traversed.

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

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

Images