JP2022510040A - Hybrid drive scheme for RGB color tuning - Google Patents

Abstract

The apparatus includes an analog current dividing circuit configured to divide the input current into a first current and a second current, and a multiplexer array containing a plurality of switches, said during the first part of the cycle. The first current is simultaneously delivered to the first of the three colors of the LED and the second current to the second of the three colors of the LED during the second part of the cycle. The first current is simultaneously provided to the second color of the three colors of the LED and the second current to the third color of the three colors of the LED, and the third part of the cycle. During the same time, the first current is supplied to the first color of the three colors of the LED array, and the second current is supplied to the third color of the three colors of the LED at the same time.

Description

This application claims priority benefit to US Patent Application No. 16 / 258,193 filed on January 25, 2019. US Patent Application No. 16 filed on August 16, 2019. It claims the benefit of priority over / 543,230 and the benefit of European Patent Application No. 191655277.3 filed on March 27, 2019, each of which in its entirety. Use here.

A light emitting diode (LED) is a semiconductor light source that emits light when an electric current flows through it. When an appropriate current is applied to the LED, electrons can recombine with electron holes within the LED, releasing energy in the form of photons. This effect is called electroluminescence. The color of the emitted light corresponds to the energy of the photons and is determined by the energy bandgap of the semiconductor. White light can be obtained by using a plurality of semiconductors or by using a layer of wavelength conversion material on the semiconductor device.

An LED circuit, also referred to as an LED driver, is an electrical circuit used to power an LED by providing an appropriate current. This circuit must provide sufficient current to light the LED with the required brightness, but must limit the current to prevent damaging the LED. There needs to be a balance between sufficient current to power the LED and limiting the current to prevent damage. This is because the voltage drop across the LED is substantially constant over a wide range of operating currents. This causes a small increase in the applied voltage to significantly increase the current.

Multiple LED combinations are often used in red-green-blue (RGB) color tuning schemes. The further increase in LEDs and the requirement to power each LED in RGB color tuning add further complexity to the RGB LED drive scheme.

The apparatus includes an analog current dividing circuit configured to divide the input current into a first current and a second current, and a multiplexer array containing a plurality of switches, said during the first part of the cycle. The first current is simultaneously delivered to the first color of the three colors of the LED and the second current to the second color of the three colors of the LED during the second part of the cycle. The first current is simultaneously provided to the second color of the three colors of the LED and the second current to the third color of the three colors of the LED, and the third part of the cycle. During the same time, the first current is supplied to the first color of the three colors of the LED array, and the second current is supplied to the third color of the three colors of the LED at the same time.

A more detailed understanding can be obtained from the following explanation given as an example together with the attached drawings.
A CIE chromaticity diagram showing a color space is shown. Figures are shown illustrating their relationship to various CCTs and BBLs. An example of a hybrid drive circuit for RGB tuning is shown. It shows a microcontroller for computing devices that handles complex signal processing with less PCB resources than analog circuits. Shown is a color chart of the circuit of FIG. 1C in which a red LED (or an array of red LEDs) is centrally located. Shown is a color chart of the circuit of FIG. 1C in which a green LED (or an array of green LEDs) is centrally located. Shown is a color chart of the circuit of FIG. 1C in which a blue LED (or an array of blue LEDs) is located in the center position. Other hybrid drive circuits are shown. Shown is a color chart of the circuit of FIG. 1H in which red and blue LEDs (or an array of red LEDs and an array of blue LEDs) are driven by analog current. Shown is a color chart of the circuit of FIG. 1H in which red and green LEDs (or an array of red LEDs and an array of green LEDs) are driven by analog current. Shown is a color chart of the circuit of FIG. 1H in which blue and green LEDs (or an array of blue LEDs and an array of green LEDs) are driven by analog current. Other hybrid drive circuits are shown. A color chart of the circuit of FIG. 1L that provides coverage over the entire area is shown. A hybrid drive method for RGB color tuning drive is shown. It is a top view of the electronics substrate for the integrated LED lighting system according to one Embodiment. It is a top view of the electronics board which attached the LED array to the board in the LED device mounting area in one Embodiment. It is a figure which shows one Embodiment of the 2-channel integrated LED lighting system which electronic components were attached to the two surfaces of a circuit board. It is a figure which shows one Embodiment of the LED lighting system which has an LED array on an electronic board which is separate from a driver and a control circuit. FIG. 6 is a block diagram of an LED lighting system having an LED array with a portion of an electronic circuit on an electronics substrate separate from the driver circuit. It is a figure of the LED lighting system example which shows the multi-channel LED driver circuit. An example of an application system is shown. It is a figure which shows the LED device. It is a figure which shows a plurality of LED devices.

Hereinafter, examples of different light lighting systems and / or light emitting diode (“LED”) implementations will be further described with reference to the accompanying drawings. These examples are not mutually exclusive and the features found in one example can be combined with the features found in one or more other examples to achieve further implementation. It is therefore understood that the examples shown in the accompanying drawings are provided solely for illustrative purposes and are by no means intended to limit this disclosure. Throughout, similar elements are referenced with similar codes.

It is understood that terms such as first, second, third, etc. may be used here to describe various elements, but these elements should be limited by these terms. Not. These terms can be used to distinguish one element from another. For example, the first element may be referred to as a second element and the second element may be referred to as a first element without departing from the scope of the present invention. As used herein, the term "and / or" may include any and all combinations of one or more of the items listed in association.

It is understood that when an element, such as a layer, region, or substrate, is referred to as being "on" or "up" on another element, it is directly of the other element. It may be on or extend directly above it, or there may be intervening elements. In contrast, when one element is referred to as being "directly above" or "directly above" extending from another element, there may be no intervening element. It is also understood that when an element is referred to as being "connected" or "bonded" to another element, it may be directly connected or connected to another element. And / or may be connected or coupled to other elements via one or more intervening elements. In contrast, when an element is referred to as "directly connected" or "directly coupled" to another element, there is no intervening element between that element and the other element. To be understood, these terms are intended to include elements in different orientations in addition to the orientations depicted in the figure.

Here, for example, "downward", "upper", "upper", "lower" to describe the relationship between one element, layer or region and another element, layer or region as shown in the figure. Relative terms such as "," horizontal "or" vertical "may be used. It is understood that these terms are intended to include devices in different orientations in addition to the orientations depicted in the figure.

Also, whether LEDs, LED arrays, electrical components, and / or electronic components are placed on one, two, or more electronic substrates may also depend on design constraints and / or applications.

Light output emitting devices, such as semiconductor light emitting devices (LEDs), or devices that emit light output of, for example, ultraviolet (UV) or infrared (IR), are among the most efficient light sources currently available. These devices may include light emitting diodes, resonator type light emitting diodes, vertical resonator laser diodes, end face light emitting lasers, or the like. LEDs, for example, due to their small size and lower power requirements, can be attractive candidates for a number of different applications. For example, they can be used as light sources for handheld battery-powered devices such as cameras and mobile phones (eg, flash light and camera flash). They also include, for example, automotive lighting, head-up display (HUD) lighting, garden lighting, street lighting, torch for video, general lighting (eg, home, store, office and studio lighting, theater / stage lighting, and It is used for architectural lighting), augmented reality (AR) lighting, virtual reality (VR) lighting, used as a backlight for displays, and can also be used for IR spectroscopy. A single LED will provide less bright light than an incandescent light source, and therefore in applications where brighter is desired or required, a multi-junction device or array of LEDs (eg, monolithic LED array, micro). LED arrays, etc.) can be used.

This description is a hybrid drive for driving an unsaturated RGB color LED that produces white with a high color rendering index (CRI) and high efficiency, especially dealing with color mixing using phosphor-converted color LEDs. Directed to the scheme. The forward voltage of the direct color LED decreases as the main wavelength becomes longer. These LEDs are best driven using a multi-channel DC / DC converter. New fluorescent conversion color LEDs aimed at high efficacy and CRI will be created, opening up new possibilities for correlated color temperature (CCT) tuning applications. These new color LEDs have unsaturated (pale shade) color points and can be mixed to achieve white with a 90+ CRI over a wide CCT range. Other LEDs may implement 80 CRIs, and 70 CRI implementations may also be used. These possibilities require LED circuits that realize and maximize this potential. At the same time, the control circuit may be compatible with a single channel constant current driver to facilitate market adoption.

Generally, the LED drive circuit is formed using an analog approach or a pulse width modulation (PWM) approach. With an analog driver, all colors are driven at the same time. By providing different currents to each LED, each LED is driven independently. The analog driver causes a certain color shift, and there is currently no way to shift the current in three ways. Analog drive often results in LEDs of a particular color being driven to a low current mode and, at times, to a very high current mode. Such wide dynamic range poses challenges to sensing and control hardware.

In PWM, each color is switched on in order at high speed. Each color is driven by the same current. The mixed color is controlled by changing the duty cycle of each color. That is, one color can be driven twice as long as another to add to the mixed color. Light appears to have a single color because human vision cannot perceive colors that change very quickly.

For example, the first LED is driven with a certain current over a specific amount of time, then the second LED is driven with the same current over a specific time, and the third LED is driven with a specific amount of time. Driven by that current over. The mixed color is controlled by changing the duty cycle of each color. For example, if you have an RGB LED and want a particular output, based on the perception of the human eye, red is driven in one part of the cycle, green is driven in another part of the cycle, and then the cycle. Blue can be driven in yet another part of. Instead of driving the red LED with a lower current, it drives with the same current for a shorter period of time. This example illustrates the downside of PWM that LEDs are not fully utilized and result in inefficiencies.

A comparison of these two drive schemes is summarized in Table 1 below. Table 1 exemplifies the advantages and disadvantages of each drive technology. As shown, analog drive provides good LED utilization, peak current sharing by all colors, and generally good LED effectiveness and overall effectiveness. PWM provides good color point predictability as all LEDs are driven at peak currents by a relatively simple and efficient controller.

The drive scheme includes a hybrid scheme that achieves the combined benefits of the analog and PWM approaches described above. The hybrid system divides the input current between the two colors each time, treating the two color sets as virtual LEDs so that they overlap the PWM time slicing. This drive scheme uses the same number of LEDs to achieve the same level of overall effectiveness as analog drive, while maintaining good color predictability. Compared to hybrid drive schemes, PWM drive schemes may require as much as 50% more LEDs to achieve the same effectiveness. The advantages of this hybrid drive scheme are added to Table 1 and presented in Table 2 below. Hybrid drive captures the advantages of analog drive in LED utilization, current rating, LED effectiveness and overall effectiveness, as well as the use of the included PWM drive color point predictability and controller complexity advantages.

FIG. 1A shows CIE chromaticity FIG. 1 representing a color space. The color space is a three-dimensional space, that is, the color is defined by a set of three numbers that define the color and brightness of a particular uniform visual stimulus. These three numbers can be International Commission on Illumination (CIE) coordinates X, Y, and Z, or other values such as hue, saturation, and brightness. Based on the fact that the human eye has three different types of color-sensitive cones, the eye response is best explained in terms of these three "tristimulatory values".

Chromaticity FIG. 1 is a color space projected onto a two-dimensional space ignoring luminance. For example, the standard CIE XYZ color space corresponds to the chromaticity space defined by the two chromaticity coordinates x, y. Saturation objectively defines the quality of a color regardless of its brightness. Saturation consists of two independent parameters, often defined as hue and saturation. Saturation may be referred to instead as saturation, chroma, intensity, or stimulus purity. Saturation Figure 1 contains colors that are perceptible to the human eye. Saturation Figure 1 uses parameters that are based on the spectral power distribution (SPD) of light emitted from a colored object and that are coefficiented by a sensitivity curve measured for the human eye. Both colors can be accurately represented in terms of the two color coordinates x and y. The colors that can be matched by combining a given set of three primary colors, ie blue, green, and red, are the coordinates of these three colors, ie, red coordinates 3, green coordinates 4, and blue coordinates. It is represented on the chromaticity diagram by the triangle 2 connecting 5. The triangle 2 represents the color gamut.

Chromaticity FIG. 1 includes a plank locus or blackbody locus (BBL) 6. BBL6 is a path or locus that the color of an incandescent blackbody follows within a particular chromaticity space as the temperature of the blackbody changes. It passes through deep red to orange, yellowish white, and white at low temperatures, and finally becomes bluish white at very high temperatures. Generally speaking, the human eye prefers white color points that are not too far from BBL6. Color points above BBL6 will appear excessively green, and color points below it will appear excessively pink.

FIG. 1B shows FIG. 10 illustrating their relationship to various CCTs and BBL6. Using the three primary colors (R, G, B) and driving two colors at the same time creates three virtual color points (RG, RB, GB) that produce the color gamut 2.1 of this drive scheme. Is done. This new color gamut 2.1 is smaller than the old color gamut 2. Between 2700K and 4000K, the color line runs under BBL6 within 3 STEPs. This deviation is within the range of human preference slightly below BBL6 for warm CCT. As will be appreciated by those skilled in the art, the primary color points may be adjusted so that the color gamut 2.1 completely surrounds the tunable band of interest. Efficiency and availability are improved by forcing the current to be split between the two colors.

FIG. 1C shows a circuit example 20 of a hybrid drive circuit for RGB tuning. The circuit 20 includes an LED driver 25 that is electrically connected to a voltage regulator 24 and together generate a stabilized current lo, an analog current shunt circuit 21, a multiplexer array 22, and an LED array 23.

The LED array 23 has one or more first color (color 1) LEDs 26 and one or more second color (color 2) LEDs designed to be tuned using a hybrid drive circuit. And one or more third color (color 3) LEDs 28. In one embodiment of circuit 20, color 1 is green, color 2 is red, color 3 is blue, but any set of colors may be used for color 1, color 1, and color 3. .. As will be appreciated, assigning a color to a particular channel is merely a design choice and other designs may be intended, but this description provides a complete understanding of the hybrid drive circuits described herein. To describe an embodiment in which color 1 LED26, color 2 LED27, and color 3 LED28 are used, color 1 is described as green, color 2 is described as red, and color 3 is described as blue. Can be.

The circuit 20 includes an analog current shunt circuit 21 that divides the input current I ₀ into two currents I ₁ and I ₂ . Such an analog current shunt circuit 21 is described in US Patent Application No. 16 / 145,053 entitled AN ARBITRARY-RATIO ANALOG CURRENT DIVISION CIRCUIT, which is described as if it were in its entirety. Use here as if it were done. The analog current shunt circuit 21 may take the form of a drive circuit that provides equal current for each of the two colors. The analog current shunt circuit 21 can address forward voltage discrepancies between LEDs of different colors while allowing precise control of the drive current for each color. Alternatively, the analog current shunt circuit 21 may allow unequal shunting of current, which cannot be achieved by simply switching both strings on. As will be appreciated, other analog current divider circuits may also be utilized without departing from the spirit of the invention. The analog current shunt circuit 21 is provided as an exemplary shunt for a complete understanding of the hybrid drive circuit described herein.

The analog current shunt circuit 21 may be mounted on a printed circuit board (PCB) to work with the LED driver 25 and the LED array 23. The LED driver 25 may be a conventional LED driver known in the art. The analog current shunt circuit 21 may allow the LED driver 25 to be used in applications that utilize two or more LED arrays 23.

Each current channel of the analog current shunt circuit 21 may include a sense resistor. For example, in one embodiment having two current channels, the analog current shunt circuit 21 has a first sense resistor (Rs1) 29 in Vsense1 that detects the first voltage of the first current channel 31 and a second in Vsense2. It includes a second sense resistor (Rs2) 30 that detects the second voltage of the current channel 32. The voltage in Vsense1 represents the current flowing through the first sense resistor (Rs1) 29, and the voltage in Vsense2 represents the current flowing through the second sense resistor (Rs2) 30.

The analog current shunt circuit 21 includes a computing device 37. The calculation device 37 is configured to compare the first detection voltage Vsense1 and the second detection voltage Vsense2 to determine the set voltage Vset. When the first detection voltage Vsense1 is lower than the second detection voltage Vsense2, the calculation device 37 is configured to increase the Vset. When the first detection voltage Vsense1 is higher than the second detection voltage Vsense2, the calculation device 37 is configured to lower the set voltage Vset.

Specifically, the computational device 37 may include an operational amplifier (op amp) 38, a capacitor 39 between the position of the set voltage Vset and ground, and a resistance 41 in parallel with the capacitor 39. The first detection voltage Vsense1 and the second detection voltage Vsense2 are sent to the operational amplifier 38. The computing device 37 may be configured to compare the first detection voltage Vsense1 with the second detection voltage Vsense2 by subtracting the first detection voltage Vsense1 from the second detection voltage Vsense2. When the first detection voltage Vsense1 is lower than the second detection voltage Vsense2 when the operational amplifier 38 is adjusted, the calculation device 37 uses the difference between the first detection voltage Vsense1 and the second detection voltage Vsense2 as the charging current. It may be configured to convert and charge the capacitor 39 to increase the set voltage Vset. When the first detection voltage Vsense1 is higher than the second detection voltage Vsense2, the calculation device 37 is configured to convert the difference between the first detection voltage Vsense1 and the second detection voltage Vsense2 into a discharge current and lower the set voltage Vset. Can be done.

Therefore, when the first detection voltage Vsense1 is higher than the second detection voltage Vsense2, the computing device 37 can lower the set voltage Vset, which in turn supplies power to the first current channel 31. Reduces Voltage1. In other words, when the operational amplifier 38 is tuned, the first detection voltage Vsense1 is substantially equal to the second detection voltage Vsense2. Therefore, during the steady state, the ratio of the current of the first current channel 31 to the current of the second current channel 32 is equal to the value of the second sense resistor Rs2 to the value of the first sense resistor Rs1, and the following equation is satisfied:
I_Rs1 = V_set / R_s1 Equation 1
I_Rs2 = V_set / R_s2 Equation 2

Therefore, when the value of the first sense resistor Rs1 is equal to the value of the second sense resistor Rs2, the current I_Rs1 flowing through the first resistor is equal to the current I_Rs2 flowing through the second resistor, and the current dividing circuit 21 generates, for example, a power supply voltage. Assuming that the current drawn by the auxiliary circuit such as is negligible, the current is divided into two equal parts. As will be appreciated by those skilled in the art, the computational device 37 shown in FIG. 1C is one of many possible implementations.

The set voltage Vset can be sent to a voltage controlled current source that can be implemented in the first operational amplifier 33. The first operational amplifier 33 may provide a first gate voltage Voltage 1. The first gate voltage Voltage 1 may be input to the first transistor 34 used to provide the drive current I ₁ . The first transistor 34 may be a conventional metal oxide film semiconductor field effect transistor (PWM). The first transistor 34 may be an n-channel MOSFET.

The second transistor 35 may provide the drive current I ₂ . The second transistor 35 may be a conventional MOSFET. The second transistor 35 may be an n-channel MOSFET. The second transistor can only be switched on when the first current channel 31 is tuned. The second gate voltage Voltage 2 may be applied to the second transistor 35.

The second gate voltage Voltage 2 may be supplied to the REF input of the shunt regulator 36. In one embodiment, the shunt regulator 36 has an internal reference voltage of 2.5V. When the voltage applied to the REF node is higher than 2.5V, the shunt regulator 36 can sink a large current. When the voltage applied to the REF node is lower than 2.5V, the shunt regulator 36 can only sink a very small quiescent current.

A large sink current can reduce the gate voltage of the second transistor 35 to a level below its threshold, which can switch the second transistor 35 off. It can be said that the shunt regulator 36 cannot pull the cathode more than the forward voltage (Vf) of the diode under the REF node. Therefore, the second transistor 35 may have a threshold voltage higher than 2.5V. Alternatively, a shunt regulator with a lower internal reference voltage, such as 1.24V, may be used.

The circuit 20 includes a multiplexer array 22 that electrically connects two of the three LEDs 26, 27, 28 to the two current sources I ₁ and I ₂ produced by the analog current shunt circuit 21. The multiplexer array 22 may include four MOSFETs S1 (11), S2 (12), S3 (13), S4 (14) also referred to as switches, as shown in circuit 20. The multiplexer array 22 leads I ₁ and I ₂ to two of the plurality of colors of the LED array 23 each time. As shown in the table below, the control of MOSFET S1 11 and MOSFET S414 is such that MOSFET S2 12 and MOSFET S3 13 have inverted values of MOSFET S1 11 and MOSFET S4 14 (that is, S2 = inverted S1 and S3 = It needs to be inverted S4). The following equation is specified:
R _s1 * I ₁ = R _s2 * I ₂ formula 3
I ₀ = 1 ₁ + I ₂ formula 4

For operation, this hybrid drive scheme utilizes an analog current shunt circuit 21 to drive two colors of the LED array 23 simultaneously and apply PWM time slicing with a third color of the LED array 23. Table 3 shows the use of LEDs in the array 23 for embodiments where color 1 is green, color 2 is red, and color 3 is blue.

When driving two colors at the same time, a virtual color point is created. The ratio between the currents I1 and I2 can be predetermined (ie, it can be 1: 1 or slightly different to maximize efficiency, but any ratio can be used). Using the three colors of the LED array 23, three virtual color points (RG, RB, GB) are combined with a primary color R / G / B (fourth color point for mixing). In addition, it can be created. The triangle formed by these three virtual color points (RG, RB, GB) defines the color gamut of this new drive scheme.

Table 4 summarizes the timing sequence of operation of the hybrid drive scheme for 3-channel LED drive. As will be appreciated by those skilled in the art, the specific order of colors is not always important. In implementing a hybrid drive scheme, multiple color duplets can be configured or reconfigured to minimize the complexity of PWM logic implementation. Table 4 is shown below to provide a timing sequence for the samples. A red-green color pair may be powered during the sub-interval T1. A green-blue color pair may be powered during the sub-interval T2. A red-blue color pair may be powered during the sub-interval T3. The sum of the sub-intervals T1, T2 and T3 is combined to substantially cover the switching period T.

FIG. 1D shows a microcontroller 40 that can be used in a computing device 37 to handle complex signal processing with less PCB resources than the analog circuits described above. The microcontroller 40 handles the input signal and the operations of S1 and S4. The microcontroller 40 can monitor the absolute value of the input current by detecting VSENSE1 at the input 15, and can monitor the substrate temperature with the NTC17. These two readings of VSENSE1 and NTC17 at input 15 can be used to compensate for color shifts due to drive current and temperature. 0-10V represents the control input 16. The microcontroller 40 may be mapped to the CCT tuning curve. The microcontroller 40 converts the input instructions into the operation of the multiplexer array 22. Specifically, the microcontroller 40 may provide a first output signal 11 for controlling the switch S1 and a second output signal 14 for controlling the switch S4.

FIG. 1E shows a color chart 42 of a circuit 20 in which a red LED (or an array of red LEDs) is located at the center. The color chart 42 is superimposed on the color chart of FIG. 1B. The color chart 42 shows a reachable color gamut 43 from the use of RB-RG-BG in circuit 20 from 2700K to 6000K (corresponding to color gamut 2.1 from FIG. 1B) and RG in circuit 20 below 2500K. -The color gamut 44 from the use of RB-R is drawn. The color gamut 43 can be provided with high efficiency. The color gamut 44 may be provided with reduced efficiency. The combination of the color gamut 43 and the color gamut 44 from the circuit 20 is close to the color gamut 2 described above with respect to FIG. 1A. The combination of the color gamut 43 and the color gamut 44 does not completely cover all of the color gamut 2, but the combination of the color gamut 43 and the color gamut 44 can be sufficient for many applications, and the hybrid circuit 20 It can be considered a reasonable trade-off for the efficiency gains achieved by.

FIG. 1F shows a color chart 45 of a circuit 20 in which a green LED (or an array of green LEDs) is arranged at a central position. The color chart 45 is superimposed on the color chart of FIG. 1B. The color chart 45 shows the reachable color gamut 43 from the use of RB-RG-BG in circuit 20 from 2700K to 6000K (corresponding to color gamut 2.1 from FIG. 1B) and circuit 20 above BBL. The color gamut 46 from the use of RG-GB-G in. The color gamut 43 can be provided with high efficiency. The color gamut 46 may be provided with reduced efficiency. The combination of the color gamut 43 and the color gamut 46 from the circuit 20 is close to the color gamut 2 described above with respect to FIG. 1A. The combination of the color gamut 43 and the color gamut 46 does not completely cover all of the color gamut 2, but the combination of the color gamut 43 and the color gamut 46 can be sufficient for many applications, and the hybrid circuit 20 It can be considered a reasonable trade-off for the efficiency gains achieved by.

FIG. 1G shows a color chart 47 of a circuit 20 in which a blue LED (or an array of blue LEDs) is located at the center. The color chart 47 is superimposed on the color chart of FIG. 1B. The color chart 47 shows the reachable color gamut 43 from the use of RB-RG-BG in circuit 20 from 2700K to 6000K (corresponding to color gamut 2.1 from FIG. 1B) and GB in circuit 20 above 6500K. -The color gamut 48 from the use of RB-B is drawn. The color gamut 43 can be provided with high efficiency. The color gamut 48 may be provided with reduced efficiency. The combination of the color gamut 43 and the color gamut 48 from the circuit 20 is close to the color gamut 2 described above with respect to FIG. 1A. The combination of the color gamut 43 and the color gamut 48 does not completely cover all of the color gamut 2, but the combination of the color gamut 43 and the color gamut 48 can be sufficient for many applications, and the hybrid circuit 20 It can be considered a reasonable trade-off for the efficiency gains achieved by.

Obviously from FIGS. 1E, 1F and 1G, all parts of the color gamut 2 can be reached by simply changing the LED located in the center of the circuit 20. In each configuration of the LED, the color gamut 2.1 is covered by adding an additional portion of the color gamut 2. Such coverage can be sufficient for many applications and can be considered a trade-off for efficiency gains.

FIG. 1H shows another hybrid drive circuit 50. Circuit 50 may provide an increased color gamut from circuit 20. The circuit 50 includes an analog current shunt circuit 21, an LED array 23, a voltage regulator 24, and an LED driver 25, as described herein with respect to FIG. 1C. As in FIG. 1C, the LED array 23 has one or more color 1 LEDs 26 and one or more color 2 LEDs 27 and 1 designed to be tuned using a hybrid drive circuit. It may include one or more color 3 LEDs 28. Circuit 50 uses a multiplexer array 52. In one embodiment of circuit 50, color 1 is green, color 2 is red, color 3 is blue, but any set of colors may be used for color 1, color 1, and color 3. .. As will be appreciated, assigning a color to a particular channel is merely a design choice and other designs may be intended, but this description provides a complete understanding of the hybrid drive circuits described herein. To describe an embodiment in which color 1 LED26, color 2 LED27, and color 3 LED28 are used, color 1 is described as green, color 2 is described as red, and color 3 is described as blue. Can be.

である。 The multiplexer array 52 electrically connects two of the three LEDs 26, 27, 28 to the two current sources I ₁ and I ₂ created by the analog current shunt circuit 21. As shown in the circuit 50, the multiplexer array 52 may include five MOSFETs S1 (51), S2 (53), S3 (54), S4 (56), S5 (57) also referred to as switches. The multiplexer array 52 leads I ₁ and I ₂ to two of the plurality of colors of the LED array 23 each time. For the control of MOSFET S151, MOSFET S456, and X, MOSFET S2 53 and MOSFET S3 54 are inverted values of MOSFET S151 and MOSFET S456, and MOSFET S5 57 is a combination of MOSFET S1 51 and MOSFET S2 53. Should be made to be an inversion of. In particular,

Is.

Table 5 shows the possible combinations provided by circuit 50. Table 5 shows the use of LEDs in the array 23 for embodiments where color 1 is green, color 2 is red, and color 3 is blue.

FIG. 1I shows a color chart 55 of a circuit 50 in which red and blue LEDs (or an array of red LEDs and an array of blue LEDs) are driven by an analog current. The color chart 55 is superimposed on the color chart of FIG. 1B. The color chart 55 depicts a reachable color gamut 43 (corresponding to color gamut 2.1 from FIG. 1B), color gamut 44, and color gamut 48. The color gamut 43 can be provided with high efficiency. The color gamuts 44, 48 may be provided with reduced efficiency. The combination of the color gamuts 43, 44, 48 from the circuit 50 is close to the color gamut 2 described above with respect to FIG. 1A. The combination of color gamuts 43, 44, 48 does not completely cover all of color gamut 2, but the combination of color gamuts 43, 44, 48 can be sufficient for many applications and is achieved by the hybrid circuit 50. It could be a reasonable trade-off for the efficiency gains made.

FIG. 1J shows a color chart 60 of a circuit 50 in which red and green LEDs (or an array of red LEDs and an array of green LEDs) are driven by an analog current. The color chart 60 is superimposed on the color chart of FIG. 1B. The color chart 60 depicts a reachable color gamut 43 (corresponding to color gamut 2.1 from FIG. 1B), color gamut 44, and color gamut 46. The color gamut 43 can be provided with high efficiency. The color gamuts 44, 46 may be provided with reduced efficiency. The combination of the color gamuts 43, 44, 46 from the circuit 50 is close to the color gamut 2 described above with respect to FIG. 1A. The combination of color gamuts 43, 44, 46 does not completely cover all of color gamut 2, but the combination of color gamuts 43, 44, 46 can be sufficient for many applications and is achieved by the hybrid circuit 50. It could be a reasonable trade-off for the efficiency gains made.

FIG. 1K shows a color chart 65 of a circuit 50 in which blue and green LEDs (or an array of blue LEDs and an array of green LEDs) are driven by an analog current. The color chart 65 is superimposed on the color chart of FIG. 1B. The color chart 65 depicts a reachable color gamut 43 (corresponding to color gamut 2.1 from FIG. 1B), a color gamut 46, and a color gamut 46. The color gamut 43 can be provided with high efficiency. The color gamuts 46, 48 may be provided with reduced efficiency. The combination of the color gamuts 43, 46, and 48 from the circuit 50 is close to the color gamut 2 described above with respect to FIG. 1A. The combination of color gamuts 43, 46, 48 does not completely cover all of color gamut 2, but the combination of color gamuts 43, 46, 48 can be sufficient for many applications and is achieved by the hybrid circuit 50. It could be a reasonable trade-off for the efficiency gains made.

FIG. 1L shows another hybrid drive circuit 70. Circuit 70 may provide an increased color gamut from circuits 20, 50. The circuit 70 includes an analog current shunt circuit 21, an LED array 23, a voltage regulator 24, and an LED driver 25, as described herein with respect to FIG. 1C. As in FIG. 1C, the LED array 23 has one or more color 1 LEDs 26 and one or more color 2 LEDs 27 and 1 designed to be tuned using a hybrid drive circuit. It may include one or more color 3 LEDs 28. A multiplexer array 72 is used in circuit 70. In one embodiment of circuit 70, color 1 is green, color 2 is red, color 3 is blue, but any set of colors may be used for color 1, color 1, and color 3. .. As will be appreciated, assigning a color to a particular channel is merely a design choice and other designs may be intended, but this description provides a complete understanding of the hybrid drive circuits described herein. To describe an embodiment in which color 1 LED26, color 2 LED27, and color 3 LED28 are used, color 1 is described as green, color 2 is described as red, and color 3 is described as blue. Can be.

である。 The multiplexer array 72 electrically connects two of the three LEDs 26, 27, 28 to the two current sources I ₁ and I ₂ created by the analog current shunt circuit 21. The multiplexer array 72 may include six MOSFETs S1, S2, S3, S4, S5, S6 also referred to as switches, as shown in circuit 70. The multiplexer array 72 leads I ₁ and I ₂ to two of the plurality of colors of the LED array 23 each time. For the control of MOSFETs S1, MOSFETs S4, and X1 and _X2 , MOSFETs S2 and MOSFETs S3 _are inverted values of MOSFETs S1 and MOSFETs S4, and MOSFETs S4 and MOSFETs S6 are inverted values of the combination of MOSFETs S4 and MOSFETs S5. Need to be. In particular,

Is.

Table 6 shows the possible combinations provided by circuit 70. Table 6 shows the use of LEDs in the array 23 for embodiments where color 1 is green, color 2 is red, and color 3 is blue.

By alternating the same color between I1 and I2, any discrepancy between I1 and I2 can be averaged and removed, for example by chopping.

FIG. 1M shows a color chart 75 for circuit 70 that provides full coverage of color gamut 2. The color chart 75 is superimposed on the color chart of FIG. 1B. The color chart 75 depicts the complete reachable color gamuts 43, 44, 46, 48 that match the color gamuts described above with respect to FIG. 1A.

FIG. 1N shows a hybrid drive method 80 for RGB color tuning drive. Method 80 can be used with circuit 20, circuit 50, or circuit 70 to produce 1/2 color gamut, 3/4 color gamut, and full color gamut outputs as described herein. In the method 80, in step 82, the input current is divided into a first current and a second current by an analog current dividing circuit. In step 84, the method 80 uses a multiplexer array to transfer the first current to the first of the three colors of the LED and the second current to the three colors of the LED during the first part of the cycle. Provided at the same time for our second color. In step 86, the method 80 uses a multiplexer array to transfer the first current to the second of the three colors of the LED and the second current to the three colors of the LED during the second part of the cycle. Provided at the same time for our third color. In step 88, the method 80 uses a multiplexer array to transfer the first current to the first of the three colors of the LED and the second current to the three colors of the LED during the third part of the cycle. Provided at the same time for our third color. In method 80, connecting the first and second currents to different pairs of LEDs provides pulse width modulation (PWM) time slicing for driving to the third of the three colors of the LEDs. Can be done using. In method 80, the PWM is a combination of the first color of the three colors of the LED and the second color of the three colors of the LED and the third color of the three colors of the LED. They may be substantially equal or different from each other to the desired drive characteristics of the LED.

FIG. 2 is a top view of the electronics substrate 310 for an integrated LED lighting system according to one embodiment. In an alternative embodiment, two or more electronic boards may be used in the LED lighting system. For example, the LED array may be on a separate electronics board, or the sensor module may be on a separate electronics board. In the illustrated example, the electronics substrate 310 includes a power module 312, a sensor module 314, a connection and control module 316, and an LED mounting area 318 reserved for mounting the LED array on the substrate 320. ..

The substrate 320 mechanically supports and provides electrical coupling to electrical components, electronic components, and / or electronic modules using conductive connectors such as tracks, traces, pads, vias, and / or wires. It can be any board that can be. The substrate 320 may include one or more metallization layers arranged between or above one or more layers of a non-conductive material, such as a dielectric composite material. The power module 312 may include electrical and / or electronic elements. In one embodiment, the power module 312 includes an AC / DC conversion circuit, a DC / DC conversion circuit, a dimming circuit, and an LED driver circuit. One of the circuits 20, 50, 70 may be included in the power module 312.

The sensor module 314 may include the sensors required for the application in which the LED array is mounted. Examples of sensors may include optical sensors (eg, IR and image sensors), motion sensors, thermal sensors, mechanical sensors, proximity sensors, or even timers. As an example, LEDs in streetlights, general lighting, garden lighting applications may be based on several different sensor inputs such as the presence of detected users, detected ambient lighting conditions, detected weather conditions, or during the day. / Can be turned off / on and / or adjusted based on night time. This may include, for example, adjusting the intensity of the light output, the shape of the light output, the color of the light output, and / or turning the light on or off to save energy. In AR / VR applications, motion sensors may be used to detect user movements. The motion sensor itself may be an LED such as an IR detector LED. As another example, in camera flash applications, image sensors and / or other light sensors or pixels can be used to measure the illumination of the captured scene, thereby the color of the flash illumination, the intensity illumination pattern, and so on. And / or the shape can be optimally calibrated. In an alternative embodiment, the electronics substrate 310 does not include a sensor module.

The connection and control module 316 may include a system microcontroller and some type of wired or wireless module configured to receive control inputs from an external device. As an example, the radio module can include bluetooth®, Zigbee, Z-wave, mesh, WiFi, Near Field Communication (NFC), and / or peer-to-peer modules may be used. The microcontroller is built into the LED lighting system and receives input from a wired or wireless module or other module within the LED system (eg sensor data and data fed back from the LED module) and based on it to the other module. It can be any type of dedicated computer or processor configured or configurable to provide control signals. Algorithms implemented by special purpose processors may be implemented in computer programs, software, or firmware embedded in non-temporary computer readable storage media for execution by special purpose processors. Examples of non-temporary computer readable storage media include read-only memory (ROM), random access memory (RAM), registers, cache memory, and semiconductor memory devices. The memory may be included as part of the microcontroller or may be mounted elsewhere, either on or away from the electronics substrate 310. One of the circuits 20, 50, 70 may be included in the connection and control module 316.

The term module, as used herein, may refer to electrical and / or electronic components located on individual circuit boards that may be soldered to one or more electronic boards 310. However, the term module also refers to electrical and / or electronic components that provide similar functionality but can be individually soldered to one or more circuit boards within the same region or within different regions. There is also.

FIG. 3A is a top view of the electronic board 310 in which the LED array 410 is mounted on the board 320 in the LED device mounting area 318 in one embodiment. The electronics substrate 310, along with the LED array 410, represents the LED lighting system 400A. Further, the power module 312 receives a voltage input at Vin497, receives a control signal from the connection and control module 316 on the trace 418B, and provides a drive signal to the LED array 410 on the trace 418A. The LED array 410 is turned on and off by a drive signal from the power module 312. In the embodiment shown in FIG. 3A, the connection and control module 316 receives a sensor signal from the sensor module 314 on the trace 418C. One or more of the circuits 20, 50, 70 may be included in the power module 312 and / or the connection and control module 316.

FIG. 3B shows an embodiment of a two-channel integrated LED lighting system in which electronic components are mounted on two surfaces of a circuit board 499. As shown in FIG. 3B, the LED lighting system 400B includes a first surface 445A having an input for receiving a dimmer signal and an AC power signal, on which an AC / DC converter circuit 412 is mounted. There is. The LED system 400B includes a second surface 445B, on which a connection and control module 416 (wireless module in this example), which comprises a dimmer interface circuit 415, DC-DC converter circuits 440A and 440B, a microcontroller 472. And the LED array 410 is attached. The LED array 410 is driven by two independent channels 411A and 411B. In an alternative embodiment, a single channel may be used to provide the drive signal to the LED array, or any number of channels may be used to provide the drive signal to the LED array. For example, FIG. 3E illustrates an LED lighting system 400E with three channels, which will be described in more detail below.

The LED array 410 may include two groups of LED devices. In one embodiment, the Group A LED device is electrically coupled to the first channel 411A and the Group B LED device is electrically coupled to the second channel 411B. Each of the two DC-DC converter circuits 440A and 440B has their respective drive currents via a single channel 411A and 411B to drive the Group A and Group B LEDs in the LED array 410, respectively. Can be provided. The LEDs of one group of these LED groups may be configured to emit light with a different color point than the LEDs of the second LED group. Controlling the combined color points of the light emitted by the LED array 410 by controlling the current and / or duty cycle given by the individual DC / DC converter circuits 440A and 440B via a single channel 411A and 411B, respectively. However, it can be adjusted within a certain range. The embodiment shown in FIG. 3B does not include the sensor module (shown in FIGS. 2 and 3A), but an alternative embodiment may include a sensor module.

The illustrated LED lighting system 400B is an integrated system in which an LED array 410 and a circuit for operating the LED array 410 are provided on a single electronic substrate. Connections between modules on the same surface of circuit board 499 are above or below the surface, such as traces 431, 432, 433, 434, and 435, for exchanging, for example, voltage, current, and control signals between modules. Can be electrically coupled by interconnection or metallization (not shown). Connections between modules on the opposite surface of circuit board 499 can be electrically coupled, for example, through board penetration interconnects such as vias and metallization (not shown).

FIG. 3C shows an embodiment of an LED lighting system with an LED array on an electronics substrate separate from the driver and control circuit. The LED lighting system 400C includes a power module 452 on an electronics substrate separate from the LED module 490. One of the circuits 20, 50, 70 may be included in the power module 452. The power module 452 may include an AC / DC converter circuit 412, a sensor module 414, a connection and control module 416, a dimmer interface circuit 415, and a DC / DC converter circuit 440 on a first electronics substrate. The LED module 490 may include embedded LED calibration and configuration data 493, and an LED array 410 on a second electronics substrate. Data, control signals and / or LED driver input signals 485 can be exchanged between the power module 452 and the LED module 490 via wires that can electrically and communically couple the two modules. Embedded LED calibration and configuration data 493 may include any data required by other modules in a given LED lighting system to control how the LEDs in the LED array are driven. .. In one embodiment, the embedded calibration and configuration data 493 generates or directs the driver to power each group of LEDs A and B, eg, using a pulse width modulation (PWM) signal. It may contain the data needed by the microcontroller to make changes. In this example, the calibration and configuration data 493 is provided, for example, by the number of power channels used, the desired color point of mixed light to be provided by the entire LED array 410, and / or by the AC / DC converter circuit 412. The microcontroller 472 may be notified about the proportion of power to be provided to each channel.

FIG. 3D shows a block diagram of an LED lighting system having an LED array with a portion of the electronic circuit on an electronics board separate from the driver circuit. The LED system 400D includes a power conversion module 483 and an LED module 481 located on a separate electronics substrate. One of the circuits 20, 50, 70 may be included in the power conversion module 483. The power conversion module 483 can include an AC / DC converter circuit 412, a dimmer interface circuit 415, and a DC-DC converter circuit 440, and the LED module 481 includes embedded LED calibration and setting data 493, an LED array 410. , Sensor module 414, and connection and control module 416. The power conversion module 483 may provide the LED driver input signal 485 to the LED array 410 via a wired connection between these two electronic boards.

FIG. 3E is an example of an LED lighting system 400E showing a multi-channel LED driver circuit. In the illustrated example, the system 400E includes a power module 452 and an LED module 481 including embedded LED calibration and configuration data 493 and three groups of LEDs 494A, 494B and 494C. Although three groups of LEDs are shown in FIG. 3E, one of skill in the art will recognize that any number of groups of LEDs may be used in line with the embodiments described herein. Also, although the individual LEDs in each group are configured in series, they can be configured in parallel in some embodiments.

The LED array 491 may include a plurality of LED groups that provide light with different color points. For example, the LED array 491 may include a warm white light source by the LED 494A of the first group, a cold white light source by the LED 494B of the second group, and an intermediate white light source by the LED 494C of the third group. The warm white light source with the first group of LEDs 494A may include one or more LEDs configured to provide white light with a CCT of approximately 2700K. A cold white light source with a second group of LEDs 494B may include one or more LEDs configured to provide white light with a CCT of approximately 6500K. A warm white light source with a third group of LEDs 494C may include one or more LEDs configured to provide white light with a CCT of approximately 4000K. Although various white LEDs are described in this example, those skilled in the art will recognize that the LED array 491 is consistent with the embodiments described herein to provide mixed light outputs with different overall colors. Other color combinations are possible with sex.

The power module 452 is a tunable optical engine (not shown) that can be configured to power the LED array 491 on three separate channels (shown as LED1 +, LED2 +, and LED3 + in FIG. 3E). ) Can be included. More specifically, the tunable optical engine supplies the first PWM signal to the LED 494A of the first group, such as a warm white light source, via the first channel, and the second group via the second channel. The second PWM signal may be supplied to the LED 494B of the third group, and the third PWM signal may be supplied to the LED 494C of the third group via the third channel. Each signal supplied through each channel can be used to power the corresponding LED or LED group, and the duty cycle of the signal is the overall duration of the on and off states of each LED. The time can be determined. The duration of the on and off states can result in an overall light effect that can have light characteristics (eg, correlated color temperature (CCT), color point or brightness) based on that duration. In operation, the tunable optical engine is intended to provide mixed light with the desired emission from the LED array 491 by varying the relative magnitude of the duty cycles of the first, second and third signals. The light characteristics of each of the plurality of LED groups can be adjusted. As mentioned above, the light output of the LED array 491 may have a color point based on a combination (eg, mixing) of light emission from each of the plurality of groups of LEDs 494A, 494B and 494C.

In operation, the power module 452 receives a control input generated based on user input and / or sensor input, and controls the composite color of light output by the LED array 491 based on the control input. Signals may be provided via individual channels. In some embodiments, the user provides the LED system with an input for controlling a DC / DC converter circuit, for example by turning a knob or moving a slider that may be part of a sensor module (not shown). Can be. In addition, or instead, in some embodiments, the user uses a smartphone and / or other electronic device to illuminate the LED to send the desired color instructions to the wireless module (not shown). It may provide input to system 4000.

FIG. 4 shows an example of a system 550 that includes an application platform 560, LED lighting systems 552 and 556, and secondary optical systems 554 and 558. The LED lighting system 552 produces a light beam 561 shown between arrows 561A and 561B. The LED lighting system 556 may generate a light beam 562 between arrows 562A and 562B. In the embodiment shown in FIG. 4, the light emitted from the LED lighting system 552 passes through the secondary optical system 554, and the light emitted from the LED lighting system 556 passes through the secondary optical system 558. In an alternative embodiment, the light beams 561 and 562 do not pass through any secondary optical system. The secondary optical system may be or may include one or more optical guides. The one or more optical guides may be of the edge lit type or may have an internal opening that defines the internal edges of the optical guides. The LED lighting system 552 and / or 556 can be inserted into the internal openings of one or more light guides to inject light into the internal edges of the one or more light guides (internal opening type light guides), or , Light can be injected into the outer edge (edge lit type light guide). The LEDs in the LED lighting system 552 and / or 556 may be arranged around a base that is part of a light guide. According to one implementation, the base can be thermally conductive. According to one implementation, the base may be coupled to a heat dissipation element located on the optical guide. The heat dissipation element may be configured to receive the heat generated by the LED through a thermally conductive base and dissipate the received heat. The one or more light guides are such that the light emitted by the LED lighting systems 552 and 556 is shaped as desired, for example by gradient, chamfer distribution, narrow distribution, wide distribution, angular distribution, or the like. It can be possible to be done.

In an embodiment, the system 550 may be a camera flash system for a mobile phone, indoor residential or commercial lighting, outdoor lighting such as street lights, automobiles, medical equipment, AR / VR equipment, and robotic equipment. The integrated LED lighting system 400A shown in FIG. 3A, the integrated LED lighting system 400B shown in FIG. 3B, the LED lighting system 400C shown in FIG. 3C, and the LED lighting system 400D shown in FIG. 3D are LED lighting in the embodiment. The systems 552 and 556 are exemplified.

In an embodiment, the system 550 may be a camera flash system for a mobile phone, indoor residential or commercial lighting, outdoor lighting such as street lights, automobiles, medical equipment, AR / VR equipment, and robotic equipment. The integrated LED lighting system 400A shown in FIG. 3A, the integrated LED lighting system 400B shown in FIG. 3B, the LED lighting system 400C shown in FIG. 3C, and the LED lighting system 400D shown in FIG. 3D are LED lighting in the embodiment. The systems 552 and 556 are exemplified.

The application platform 560 may power the LED lighting system 552 and / or 556 via a power bus via line 565 or other applicable inputs, as described herein. In addition, the application platform 560 can provide an input signal via line 565 for the operation of the LED lighting system 552 and the LED lighting system 556, which is a user input / preference, sensed read, It may be based on pre-programmed or autonomously determined output, or the like. The one or more sensors may be inside or outside the housing of the application platform 560.

In various embodiments, the sensors of the application platform 560 and / or the sensors of the LED lighting system 552 and / or 556 are, for example, visual data (eg, LIDAR data, IR data, data collected via a camera, etc.). Data may be collected, such as voice data, distance-based data, travel data, environmental data, or the like, or a combination thereof. The data may relate to physical items or entities such as objects, individuals, vehicles and the like. For example, object proximity data can be collected by a sensing device for ADAS / AV based applications, which can prioritize detection and subsequent actions based on the detection of physical items or entities. Data can be collected on the basis of radiating an optical signal, such as an IR signal, by, for example, an LED lighting system 552 and / or 556, and collecting data based on the emitted optical signal. Data may be collected by a different component than the component that emits the optical signal for data collection. Continuing this example, a sensing device can be placed on the vehicle, which can emit a beam using a vertical cavity surface emitting laser (VCSEL). One or more sensors may sense a response to the emitted beam or other applicable input.

In an embodiment, the application platform 560 can represent a car and the LED lighting system 552 and the LED lighting system 556 can represent a car headlight. In various embodiments, the system 550 may represent a vehicle equipped with a steerable light beam that selectively activates a plurality of LEDs to provide steerable light. For example, an array of LEDs can be used to image or project a shape or pattern, or to illuminate only selected parts of a road. In one embodiment, the infrared camera or detector pixels in the LED lighting system 552 and / or 556 can be sensors that identify parts of the scene that require lighting (roads, pedestrian crossings, etc.).

FIG. 5A is a diagram of the LED device 200 in one embodiment. The LED device 200 may include a substrate 202, an active layer 204, a wavelength conversion layer 206, and a primary optical system 208. In other embodiments, the LED device may not include a wavelength converter layer and / or primary optical system. A plurality of individual LED devices 200 may be included in an LED array within an LED lighting system, such as, for example, one of the LED lighting systems described above.

As shown in FIG. 5A, the active layer 204 can be adjacent to the substrate 202 and emit light when excited. Suitable materials used to form the substrate 202 and the active layer 204 include sapphire, SiC, GaN, silicon, and more specifically, but not limited to, AlN, AlP, AlAs, AlSb, GaN. III-V semiconductors including, GaP, GaSb, InN, InP, InAs, InSb, II-VI semiconductors including, but not limited to ZnS, ZnSe, CdSe, CdTe, but not limited to Ge, Si. , A group IV semiconductor containing SiC, or a mixture or alloy thereof.

The wavelength conversion layer 206 may be separated from the active layer 204, may be close to the active layer 204, or may be directly above the active layer 204. The active layer 204 emits light into the wavelength conversion layer 206. The wavelength conversion layer 206 acts to further change the wavelength of the light emitted by the active layer 204. LED devices that include a wavelength conversion layer are often referred to as phosphor conversion LEDs (“PCLEDs”). The wavelength conversion layer 206 may be any luminescent material that absorbs light of one wavelength and emits light of a different wavelength, such as a transparent or translucent binder or phosphor particles in a matrix, or a ceramic phosphor element. Can include.

The primary optical system 208 may be on or above one or more layers of the LED device 200, allowing light from the active layer 204 and / or the wavelength conversion layer 206 to pass through the primary optical system 208. obtain. The primary optical system 208 may be a lens or encapsulant configured to protect these one or more layers and at least partially shape the output of the LED device 200. The primary optical system 208 may include transparent and / or translucent materials. In embodiments, light through the primary optical system can be emitted based on the Lambert distribution pattern. It is understood that one or more properties of the primary optical system 208 may be modified to produce a light distribution pattern that is different from the Lambert distribution pattern.

FIG. 5B shows a cross-sectional view of the lighting system 220 including the LED array 210 having pixels 201A, 201B, and 201C and the secondary optical system 212 in one embodiment. The LED array 210 includes pixels 201A, 201B, and 201C, each containing a wavelength conversion layer 206B, an active layer 204B, and a substrate 202B, respectively. The LED array 210 may be a monolithic LED array manufactured using wafer level processing technology, micro LEDs with dimensions less than 500 microns, or the like. The pixels 201A, 201B, and 201C in the LED array 210 may be formed using array segmentation or instead may be formed using pick-and-place technology.

The space 203 shown between one or more pixels 201A, 201B, and 201C of the LED device 200B may include voids or may be a material such as a metallic material which may be a contact (eg, n-contact), for example. May be filled with.

The secondary optical system 212 may include one or both of the lens 209 and the waveguide 207. It is understood that the secondary optical system is described according to the illustrated example, but in the embodiment, the secondary optical system 212 is used to spread the incident light (divergent optical system) or collimate the incident light. It can be used to collect into a beam (colimating optics). In an embodiment, the waveguide 207 may be a condenser and may have any applicable shape for concentrating light, such as a parabolic shape, a conical shape, a slope shape, or the like. May have. The waveguide 207 may be coated with a dielectric material, a metallization layer, or the like used to reflect or reorient the incident light. In an alternative embodiment, the illumination system may not include one or more of the conversion layer 206B, the primary optical system 208B, the waveguide 207, and the lens 209.

The lens 209 can be formed from any applicable transparent material, such as, but not limited to, SiC, aluminum oxide, diamond, or the like, or a combination thereof. The lens 209 can be used to modify the light beam input to the lens 209 so that the output beam from the lens 209 effectively meets the desired photometric specifications. Further, the lens 209 may serve one or more aesthetic objectives, for example by determining the on and / or unlit appearance of the LED devices 201A, 201B and / or 201C of the LED array 210.

Although embodiments have been described in detail, those skilled in the art will appreciate that the embodiments described herein are subject to modification given the specification without departing from the spirit of the concept of the invention. Can be done. Therefore, there is no intention that the scope of the invention is limited to the specific embodiments described in the illustration.

Claims (20)

Light emitting diode (LED) color tuning device
It has a hybrid drive circuit coupled to a multi-color LED array, and the hybrid drive circuit is
An analog current shunt circuit that generates current for at least two LED current drives,
A switching array coupled between the analog current split circuit and the multicolor LED array, wherein the switching array periodically spans a predetermined amount of time and is at least one of the at least two LED current drive sources. A switching array configured to provide current from one to at least two colors of the multicolor LED array substantially simultaneously.
Have,
LED color tuning device. The LED color tuning device further comprises an LED driver electrically coupled to the voltage regulator, the voltage regulator providing a voltage signal to the multicolor LED array, the LED driver and the voltage regulator. The LED color tuning apparatus according to claim 1, wherein the combination of the above provides a stabilized current as an input to the analog current dividing circuit. The LED color tuning apparatus according to claim 1, wherein the switching array has a multiplexer array. The LED color tuning apparatus according to claim 1, further comprising a voltage-controlled current source configured to supply current to the analog current shunt circuit that generates current for the at least two LED current drive sources. The switching array is
During the first part of the cycle, the first current from the first of the at least two LED current drives goes to the first of the three colors of the multicolor LED array, and at least. The second current from the second of the two LED current drive sources is provided substantially simultaneously to the second of the three colors of the multicolor LED array.
During the second part of the cycle, the first current is to the second color of the three colors of the multicolor LED array and the second current is to the three colors of the multicolor LED array. To the third color of the multicolor LED array, and to the first color of the three colors of the multicolor LED array, and said A second current is provided substantially simultaneously to the third color of the three colors of the multicolor LED array.
The LED color tuning apparatus according to claim 1. The LED color tuning apparatus according to claim 5, wherein the first portion, the second portion, and the third portion of the cycle can be selected by using pulse width modulation (PWM) time slicing. The LED color tuning apparatus according to claim 5, wherein the sum of the first current and the second current is substantially equal to the input current supplied from the LED driver to the analog current dividing circuit. The LED color tuning apparatus according to claim 5, wherein each of the at least two LED current drive sources is configured to supply a substantially equal amount of current to the multicolor LED array. The LED color tuning apparatus according to claim 5, wherein each of the at least two LED current drive sources is configured to supply an unequal amount of current to the multicolor LED array. The LED color tuning apparatus according to claim 1, wherein the multi-color LED array includes at least one red LED, at least one green LED, and at least one blue LED. The LED color tuning apparatus according to claim 1, wherein the multi-color LED array includes at least one unsaturated red LED, at least one unsaturated green LED, and at least one unsaturated blue LED. The LED color tuning apparatus according to claim 1, wherein the switching array has at least four switching devices. The LED color tuning apparatus according to claim 1, wherein the hybrid drive circuit is further configured to supply a pulse width modulation (PWM) time slicing signal to selected LEDs in the multicolor LED array. Light emitting diode (LED) color tuning device
A multicolor LED array with at least one unsaturated red LED, at least one unsaturated green LED, and at least one unsaturated blue LED.
The hybrid drive circuit coupled to the multi-color LED array and
Have,
The hybrid drive circuit is
An analog current shunt circuit that generates current for at least two LED current drives,
A switching array coupled between the analog current split circuit and the multicolor LED array, wherein the switching array periodically spans a predetermined amount of time and is at least one of the at least two LED current drive sources. A switching array configured to provide current from one to at least two colors of the multicolor LED array substantially simultaneously.
Have,
LED color tuning device. The LED color tuning apparatus according to claim 14, further comprising a voltage-controlled current source configured to supply current to the analog current shunt circuit that generates current for the at least two LED current drive sources. The LED color tuning device further includes a calculation device configured to compare the first detection voltage V _SENSE1 and the second detection voltage V _SENSE2 to determine and supply the set voltage _VSET . The LED color tuning device according to claim 15, wherein the set voltage is an input voltage of the voltage-controlled current source. The LED color tuning apparatus according to claim 14, wherein the hybrid drive circuit is further configured to supply a pulse width modulation (PWM) time slicing signal to selected LEDs in the multicolor LED array. The LED color tuning device further comprises an LED driver electrically coupled to the voltage regulator, the voltage regulator providing a voltage signal to the multicolor LED array, the LED driver and the voltage regulator. The LED color tuning apparatus according to claim 14, wherein the combination of the above provides a stabilized current as an input to the analog current dividing circuit. A method of tuning a multicolor light emitting diode (LED) array.
The set voltage is determined and supplied as the input voltage of the voltage-controlled current source.
The input current is divided into a first current and a second current,
Based on the color temperature determination
During the first part of the cycle, the first current is delivered to the first color of the three colors of the multicolor LED array and the second current is delivered to the three colors of the multicolor LED array at substantially the same time. Offer to the second of the colors,
During the second part of the cycle, the first current is delivered to the second color of the three colors of the multicolor LED array and the second current is delivered to the multicolor LED array at substantially the same time. The first color of the three colors of the multicolor LED array provides the third color of the three colors and delivers the first current substantially simultaneously during the third part of the cycle. And also provides the second current to the third color of the three colors of the multicolor LED array.
How to tune a multi-color LED array. 19. The multicolor LED according to claim 19, wherein the provision of the first current and the provision of the second current to different pairs of the multicolor LED arrays is performed using pulse width modulation (PWM) time slicing. How to tune an array.

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