LED point location distribution method based on blackboard lamp and blackboard lamp

Abstract

The invention relates to the field of scene lamp design, in particular to an LED point location distribution method and system based on a blackboard lamp. An LED point location distribution method based on a blackboard lamp comprises the steps that a plurality of LED lamp beads are arranged on a preset straight line and distributed in a central symmetry mode, the position of each LED lamp bead is xi, a target plane located at the position away from the LED lamp beads by a preset distance is established, a plurality of measuring points which are arranged in an array mode and located on the target plane are preset, and the position of each measuring point is yj; based on the illumination contribution degree of each LED lamp bead to each measurement point, calculating the single-point total illumination contribution degree of each measurement point in a traversal manner to obtain the total illumination distribution of the target plane; obtaining a region maximum value and a region minimum value according to the illuminance distribution matrix of the total illuminance distribution, and calculating the illuminance uniformity through the ratio of the region minimum value to the region maximum value; and carrying out optimization calculation by taking maximization of the illumination uniformity as a target through an L-BFGS-B algorithm so as to obtain an optimized lamp bead arrangement sequence.

Description

Technical Field

[0001] The present application relates to the field of scene light design, and in particular to a method and system for distributing LED points based on blackboard lights. Background Art

[0002] Due to the limitations of the use environment, design, process and technical specifications, the blackboard lamps on the market are straight strips in shape, and the lamp beads are arranged in a straight line with equal distances. However, this design actually leads to uneven distribution of illumination contribution, showing a high middle and low side shape (such as Figure 1 The existing technology can partially improve the light distribution through the light guide kit, but the overall trend remains unchanged (such as Figure 2 , geometric calculation results). According to the simulation, the lighting uniformity (minUo / maxUo) formed by the lamp beads arranged in a straight line with equal spacing is only 0.43.

[0003] The current national standard requires that the illumination uniformity of blackboard lamps must reach 0.8 or above. However, even through combined application and position adjustment, it is difficult to significantly improve the illumination uniformity of blackboard lamps arranged in equidistant lines. For example, Figure 3 The blackboard illumination uniformity shown is 0.82, only slightly above the national standard, and further adjustments to the position show no significant improvement. This indicates that the traditional equidistant linear arrangement of the LEDs has reached its performance limit and cannot meet higher uniformity requirements.

[0004] Therefore, a new blackboard lamp design is urgently needed to solve the problem of insufficient illumination uniformity in the prior art.

[0005] Based on this, this application is filed. Summary of the Invention

[0006] In response to the above technical problems, the purpose of this application is to provide an LED point distribution method based on a blackboard lamp and a blackboard lamp.

[0007] In a first aspect of the present application, a method for distributing LED points based on a blackboard lamp is provided, and the method comprises the following steps: arranging a plurality of LED lamp beads on a preset straight line and distributing them in a centrally symmetrical manner, with the position of each LED lamp bead being xi, establishing a target plane located at a preset distance from the LED lamp bead, and presetting a plurality of array-arranged measurement points located on the target plane, wherein the position of each measurement point is yj; based on the illuminance contribution of each LED lamp bead to each measurement point, ergodicly calculating the single-point total illuminance contribution of each measurement point to obtain the total illuminance distribution of the target plane; obtaining the regional maximum value and the regional minimum value according to the illuminance distribution matrix of the total illuminance distribution, and calculating the illuminance uniformity by the ratio of the regional minimum value to the regional maximum value; and performing optimization calculation by the L-BFGS-B algorithm with maximizing the illuminance uniformity as the goal to obtain an optimized lamp bead arrangement sequence.

[0008] In a further embodiment of the present application, the illuminance contribution of each LED lamp bead to each measurement point includes:

[0009] Among them, the illumination formula of each LED lamp bead is:

[0010]

[0011] Where: Eij is the illuminance contribution of the i-th LED to the j-th measurement point; φij is the angle between the light from LED bead xi to the measurement point yj and the normal; d is the distance from LED bead xi to the target plane.

[0012] In a further embodiment of the present application, the ergodic calculation of the single-point total illumination contribution of each measurement point to obtain the total illumination distribution of the target plane includes: for each measurement point yj, calculating the sum of the illumination contributions of all n LED lamp beads xi by the following formula to obtain the single-point total illumination contribution:

[0013]

[0014] The total illumination distribution is obtained by counting the single-point total illumination contributions of all measurement points yj.

[0015] In a further embodiment of the present application, the ergodic calculation of the single-point total illumination contribution of each measurement point to obtain the total illumination distribution of the target plane includes: for each measurement point yj, first screening out the LED lamp beads xu that can illuminate the measurement point yj, and sorting the LED lamp beads xu from n1 to n2; for each measurement point yj, calculating the sum of the illumination contributions of the LED lamp beads xi that can illuminate the measurement point yj by the following formula to obtain the single-point total illumination contribution:

[0016]

[0017] The total illumination distribution is obtained by counting the single-point total illumination contributions of all measurement points yj.

[0018] In a further scheme of the present application, the regional maximum and regional minimum are obtained according to the illumination distribution matrix of the total illumination distribution, and the illumination uniformity is calculated by the ratio of the regional minimum and the regional maximum, including: erroneously selecting several sub-regions in the target plane, wherein each sub-region includes at least one measurement point; calculating the illumination average value of the single-point total illumination contribution of the measurement points contained in each sub-region; sorting the illumination average values ​​to obtain the regional maximum and the regional minimum, and using the ratio of the regional minimum and the regional maximum as the illumination uniformity.

[0019] In a further solution of the present application, the L-BFGS-B algorithm is used to perform optimization calculations with the goal of maximizing the illumination uniformity to obtain an optimized lamp bead arrangement sequence, including: taking the negative of the illumination uniformity as the objective function; defining the constraints of the LED lamp beads and providing the initial arrangement positions of the LED lamp beads; inputting the objective function, the initial arrangement position and the constraints, and gradually searching the lamp bead arrangement sequence to minimize the objective function area, thereby obtaining the optimized lamp bead arrangement sequence.

[0020] In a further scheme of the present application, the LED point distribution method also includes: after obtaining the optimized lamp bead arrangement sequence, removing the LED lamp beads with overlapping positions in the lamp bead arrangement sequence to obtain the target lamp bead arrangement sequence (the new program does not require manual optimization); using the target lamp bead arrangement sequence as input, calculating the illumination contribution of each measurement point on the target plane and calculating the total illumination distribution; obtaining the regional maximum and regional minimum according to the illumination distribution matrix of the total illumination distribution, and verifying the target lamp bead arrangement sequence through the regional minimum of the regional maximum.

[0021] In a further scheme of the present application, the verification of the target lamp bead arrangement sequence through the regional minimum of the regional maximum includes: obtaining the ratio of the minimum value and the maximum value to calculate the illumination uniformity, and the verification is successful when the illumination uniformity is greater than the preset uniformity threshold; and / or obtaining the regional average value based on the total illumination distribution, and based on the first ratio of the minimum value and the regional average value, and the second ratio of the maximum value and the regional average value, when the first ratio and the second ratio are within the preset uniformity range threshold, the verification is successful.

[0022] In a second aspect of the present application, a blackboard lamp is further provided, which includes: a housing; a light source module, including a plurality of LED lamp beads, and the LED lamp beads are distributed according to the above LED point distribution method.

[0023] In summary, the LED point distribution method and system based on blackboard lamp proposed in the general inventive concept of this application have at least the following technical effects:

[0024] The method provided in the application is an LED point distribution method based on optical modeling and numerical optimization. Through illumination contribution analysis and constrained optimization algorithm, the illumination uniformity on the target plane is maximized. The core lies in optimizing the spatial position of LED lamp beads through the L-BFGS-B algorithm to achieve the optimal solution for light distribution. Specifically, based on the illumination of the point light source, the illumination contribution of each LED lamp bead to the measurement point on the target plane is calculated: through the principle of linear superposition, the total illumination contribution of all LED lamp beads to each measurement point is calculated, and the illumination distribution matrix of the target plane is generated. The finite memory quasi-Newton method (L-BFGS-B) is used for optimization. The position of the LED lamp bead is used as the optimization variable. By iteratively updating the position of the LED lamp bead, the optimal solution is gradually approached. In this way, the uniformity of the lighting design can be quantitatively evaluated through illumination uniformity, providing a scientific design basis, reducing subjective judgment errors, and improving design reliability. For blackboard lamps, the layout of LED lamp beads can be optimized, unnecessary lighting intensity can be reduced, and energy consumption can be reduced. Under the premise of ensuring uniform illumination, the number of LED lamp beads can be reduced, hardware costs can be reduced, and at the same time, uniform illumination of the illuminated surface can be ensured, thereby improving teaching effectiveness.

[0025] Other features and advantages of the embodiments of the present invention will be described in the subsequent specific implementation examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without any creative work.

[0027] Figure 1 This is a general flow chart of the LED point distribution method based on the blackboard lamp provided in the embodiment of the present application;

[0028] Figure 2 The illumination uniformity of the blackboard lamps arranged in an equidistant straight line provided in the embodiment of the present application;

[0029] Figure 3 This is the geometric calculation result of the illumination distribution of the blackboard lights arranged in an equidistant straight line provided in the embodiment of this application;

[0030] Figure 4 This is the DIAlux simulation result of applying the blackboard lamp combination with equal distance and straight line arrangement provided in the embodiment of the present application on the blackboard surface;

[0031] Figure 5 The illumination uniformity calculation result after autonomous optimization by the program provided in the embodiment of this application;

[0032] Figure 6 Comparison of the equidistant linear arrangement of lamp beads provided in the embodiment of this application with the lamp bead position illumination curve generated by the optimization program;

[0033] Figure 7 This is a schematic diagram of the illumination superposition when the blackboard lamp combination provided in the embodiment of the present application is used. DETAILED DESCRIPTION

[0034] The terms "second direction", "first direction", "third direction", "inside", "outside" and the like that appear below to indicate directions or positional relationships, unless otherwise specified, are to be understood as being based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting this application.

[0035] Furthermore, the use of "first" or "second" in describing features is for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features identified. Features identified as "first" or "second" may explicitly or implicitly include at least one of the identified features. The use of the word "plurality" generally implies at least two, such as two or three, unless otherwise specifically defined.

[0036] In this application, unless otherwise specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integration; mechanical connections, electrical connections, direct connections, or indirect connections through an intermediary; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0037] In the description of this specification, if the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0038] Reference Figure 1 , this application first provides a LED point distribution method based on a blackboard lamp, including:

[0039] Step S10: Arrange a plurality of LED lamp beads on a preset straight line and in a centrally symmetrical distribution, with the position of each LED lamp bead being denoted as xi, establish a target plane located at a preset distance from the LED lamp bead, and pre-set a plurality of measurement points arranged in an array on the target plane, with the position of each measurement point being denoted as yj;

[0040] Step S20: Based on the illuminance contribution of each LED lamp bead to each measuring point, ergodicly calculate the single-point total illuminance contribution of each measuring point to obtain the total illuminance distribution of the target plane;

[0041] Step S30: obtaining the regional maximum value and the regional minimum value according to the illumination distribution matrix of the total illumination distribution, and calculating the illumination uniformity by the ratio of the regional minimum value to the regional maximum value;

[0042] Step S40: performing optimization calculations using the L-BFGS-B algorithm with the goal of maximizing illumination uniformity to obtain an optimized lamp bead arrangement sequence.

[0043] Specifically, multiple LED lamp beads are arranged along a preset straight line, and the arrangement is centrally symmetrical. In simple terms, the distribution of the lamp beads on the straight line is symmetrical, and the number and position of the lamp beads on the left and right sides are corresponding.

[0044] The position of each LED is represented by the coordinate xi, where i is the LED number (e.g., x1, x2, x3, etc.). A target plane is established at a certain distance from the LEDs; this plane is typically a blackboard or other surface that requires uniform illumination. Multiple measurement points are preset on the target plane, arranged in an array (e.g., a grid). The position of each measurement point is represented by the coordinate yj, where j is the measurement point number (e.g., y1, y2, y3, etc.).

[0045] For each LED, calculate its contribution to the illumination at each measurement point. Illuminance contribution refers to the effect of an LED on the light intensity at a particular measurement point. By traversing all LEDs and measurement points, calculate the total illumination contribution at each measurement point—the sum of all the LED contributions to that measurement point—and ultimately obtain the total illumination distribution on the target plane.

[0046] Based on the total illuminance distribution described above, an illuminance distribution matrix is ​​generated. From this matrix, the minimum illuminance value (regional minimum) and the maximum illuminance value (regional maximum) within the region are found. The illuminance uniformity is calculated by calculating the ratio of the regional minimum to the regional maximum. "Illuminance uniformity" can be understood as an indicator that measures the uniformity of light distribution on the target plane.

[0047] In a further solution of the present application, the arrangement of LED lamp beads is optimized using the L-BFGS-B algorithm; the optimization goal is to maximize the illumination uniformity in the search direction, and through optimization calculation, an optimized LED lamp bead arrangement sequence is obtained, so that the light distribution on the target plane is more uniform.

[0048] It can be understood that the optimization goal is to maximize illumination uniformity U, that is, by adjusting the position xi of each LED bead to make the light distribution on the target plane as uniform as possible. Since illumination uniformity is the ratio of the regional minimum to the regional maximum, the optimization problem can be understood as maximizing the illumination uniformity goal; the variables are defined as the position coordinates of the bead, such as the position xi of the LED bead (i = 1, 2...N), where N is the total number of LED beads; the position xi is the parameter that the optimization algorithm needs to adjust. By presetting constraints, such as LED lamp beads must be arranged on a preset straight line, and the position xi needs to meet certain range restrictions; the objective function is the illumination uniformity U; first initialize and set the parameters of the L-BFGS-B algorithm (such as the maximum number of iterations, convergence accuracy, etc.), for the current LED lamp bead position, respectively calculate the illumination contribution of each LED lamp bead to all measurement points on the target plane; calculate the total illumination of each measurement point, and extract the regional minimum and regional maximum to calculate the objective function value, and then calculate the gradient of the objective function for each optimization variable (i.e., the position xi of each LED lamp bead). The gradient calculation can be numerically or analytically calculated. Based on the current objective function value and gradient, the L-BFGS-B algorithm is continuously used to update the position xi of each LED lamp bead to determine whether the new LED lamp bead position xi meets the constraints. If the change in the objective function value f is less than the preset threshold or the maximum number of iterations is reached, the optimization is stopped; otherwise, the iteration is returned to continue. The final output is the optimized LED lamp bead position xi and the maximized illumination uniformity U.

[0049] In summary, the method provided by this application is a method for LED point distribution based on optical modeling and numerical optimization. It maximizes the illumination uniformity on the target plane through illumination contribution analysis and constrained optimization algorithm. The core is to optimize the spatial position of LED lamp beads through the L-BFGS-B algorithm to achieve the optimal solution for light distribution. Specifically, based on the illumination of the point light source, the illumination contribution of each LED lamp bead to the measurement point on the target plane is calculated: through the principle of linear superposition, the total illumination contribution of all LED lamp beads to each measurement point is calculated, and the illumination distribution matrix of the target plane is generated. The finite memory quasi-Newton method (L-BFGS-B) is used for optimization, and the position of the LED lamp bead is used as the optimization variable. By iteratively updating the position of the LED lamp bead, the optimal solution is gradually approached. In this way, the uniformity of the lighting design can be quantitatively evaluated through illumination uniformity, a scientific design basis can be provided, subjective judgment errors can be reduced, and design reliability can be improved. For blackboard lights, the layout of LED lamp beads can be optimized to reduce unnecessary lighting intensity and energy consumption; while ensuring uniform illumination, the number of LED lamp beads can be reduced to reduce hardware costs, while ensuring uniform illumination of the illuminated surface and improving teaching effects.

[0050] Specifically, the illuminance contribution of each LED lamp bead to each measurement point includes: wherein the illuminance formula of each LED lamp bead is expressed as:

[0051]

[0052] Where: Eij is the illuminance contribution of the i-th LED to the j-th measurement point; φij is the angle between the light from LED bead xi to the measurement point yj and the normal; d is the distance from LED bead xi to the target plane.

[0053] It can be understood that using the above formula, the illuminance contribution of each LED lamp bead to the measurement point can be accurately calculated to ensure the accuracy of the illuminance distribution.

[0054] In one embodiment, ergodic calculation of the single-point total illumination contribution of each measurement point to obtain the total illumination distribution of the target plane includes:

[0055] Step S21: For each measurement point yj, the sum of the illumination contributions of all n LED lamp beads xi is calculated using the following formula to obtain the total illumination contribution of the single point:

[0056]

[0057] Step S22: Count the single-point total illumination contributions of all measurement points yj to obtain the total illumination distribution.

[0058] As you can understand, the total illuminance contribution of each measurement point on the target plane is calculated to obtain the illuminance distribution of the entire plane. For each measurement point yj, all LED lamp beads xi are traversed, and the illuminance contribution of each LED lamp bead to yj is calculated. The contributions of all LED lamp beads are added together to obtain the total illuminance contribution of yj at a single point. It should be noted that if the illuminance contribution of a certain LED lamp bead to the measurement point yj is 0, it means that the light angle range of the LED lamp bead cannot illuminate yj. In this case, the contribution of the LED lamp bead to yj is 0.

[0059] The luminous angle of LED lamp beads is limited. If the measuring point yj is not within the irradiation range of the LED lamp beads, then = 0, resulting in a 0 illumination contribution; for example, the luminous angle of the LED lamp is if Then judge For each measurement point yj, the sum of the illumination contributions of all LED lamp beads is calculated.

[0060] In another embodiment of the present application, ergodic calculation of the single-point total illumination contribution of each measurement point to obtain the total illumination distribution of the target plane includes:

[0061] Step S21′: for each measurement point yj, first screen out the LED lamp beads xu that can illuminate the measurement point yj, and sort the LED lamp beads xu from n1 to n2;

[0062] Step S22′: For each measurement point yj, the sum of the illuminance contributions of the LED lamp beads xi that can illuminate the measurement point yj is calculated using the following formula to obtain the single-point total illuminance contribution:

[0063]

[0064] Step S23 ′: Count the single-point total illumination contributions of all measurement points yj to obtain the total illumination distribution.

[0065] For each measurement point yj, select the LED lamp beads xu that can illuminate the point; the above LED lamp beads are located in the effective lighting range of the measurement point; and sort the selected LED lamp beads from n1 to n2. The purpose of sorting is to facilitate subsequent calculations and statistics.

[0066] For each measurement point yj, use the following formula to calculate the illumination contribution Eij of each LED bead xi that can illuminate that point. Repeat steps S10 and S20 for each measurement point yj to calculate its single-point total illumination contribution Ej. The single-point total illumination contribution Ej of all measurement points is summed up to form the total illumination distribution of the target plane. This distribution reflects the illumination uniformity and intensity of the entire plane.

[0067] In one embodiment, obtaining a regional maximum value and a regional minimum value according to an illumination distribution matrix of the total illumination distribution, and calculating illumination uniformity by a ratio of the regional minimum value to the regional maximum value includes:

[0068] Step S31, ergodicly selecting a plurality of sub-regions in the target plane, wherein each sub-region includes at least one measurement point;

[0069] Step S32: Calculate the average illuminance contribution of the single-point total illuminance of the measurement points included in each sub-area;

[0070] Step S33: sort the illumination average values ​​to obtain the regional maximum value and the regional minimum value, and use the ratio of the regional minimum value to the regional maximum value as the illumination uniformity.

[0071] Within the target plane, several subregions are selected in a traversal manner. Each subregion contains at least one measurement point; the division of subregions can be flexibly adjusted according to actual needs. For example, the target plane can be divided into a regular grid, with each grid as a subregion. For each subregion, the single-point total illumination contribution Ej of the measurement point contained in it is extracted, and the average illumination value of all measurement points in each subregion is calculated:

[0072]

[0073] Among them, Average k is the average illumination value of the kth sub-area; N k is the number of measurement points in the kth sub-area; Ej is the single point total illumination contribution of measurement point yj; Average is the average illumination value of all sub-areas k Sort the areas and find the minimum (regional minimum) and maximum (regional maximum) values. Calculate illumination uniformity using the ratio of the regional minimum to the regional maximum: illumination uniformity = regional minimum / regional maximum. Illumination uniformity ranges from [0, 1], with values ​​closer to 1 indicating a more uniform illumination distribution. This embodiment provides a method for quantifying illumination uniformity by dividing the areas into subareas, calculating the average illumination value, and calculating illumination uniformity using the ratio of the regional minimum to maximum values. This method is flexible and intuitive, effectively supporting the optimization and evaluation of lighting designs. It is understood that if a subarea has only one measurement point, illumination uniformity can be understood as the ratio of the maximum to minimum values ​​at that measurement point.

[0074] Further in step S40, an optimization calculation is performed using the L-BFGS-B algorithm with the goal of maximizing illumination uniformity to obtain an optimized lamp bead arrangement sequence, including:

[0075] Step S41: using the negative of illumination uniformity as the objective function;

[0076] Step S42: defining the constraint conditions of the LED lamp beads and providing the initial arrangement positions when the LED lamp beads are equally spaced;

[0077] Step S43: input the objective function, the initial arrangement position and the constraint conditions, and gradually search the lamp bead arrangement sequence through the L-BFGS-B algorithm to minimize the objective function area, thereby obtaining the optimized lamp bead arrangement sequence.

[0078] Since the L-BFGS-B algorithm is an optimization algorithm for minimizing the objective function, the goal is to maximize illumination uniformity. The negative of illumination uniformity needs to be used as the objective function: f(x) = -illuminance uniformity, where x is the arrangement sequence of LED beads (position parameter). Illumination uniformity is the ratio of the regional minimum value to the regional maximum value. It can be understood that by minimizing the objective function f(x), illumination uniformity is maximized. Define the constraints of the LED bead arrangement, such as the spacing range between LED beads (to avoid the beads being too dense or too sparse), the arrangement range of LED beads, etc. Provide the initial arrangement position of the LED beads, and choose an equidistant arrangement as the initial condition to facilitate the algorithm to optimize on this basis. Input the following parameters into the L-BFGS-B algorithm:

[0079] The L-BFGS-B algorithm uses an objective function f(x), an initial arrangement (equally spaced), and constraints (such as minimum spacing and arrangement range). The algorithm iteratively adjusts the positions of the LEDs, gradually reducing the objective function f(x) (i.e., increasing illumination uniformity). The specific process includes calculating the gradient (or approximate gradient) of the objective function, searching for the optimal solution within the constraints, updating the positions of the LEDs, and outputting the optimized LED arrangement sequence when the algorithm converges. This sequence maximizes illumination uniformity on the target plane while satisfying the constraints.

[0080] In this application, the input objective function, the initial arrangement position and the constraint conditions are gradually searched for the lamp bead arrangement sequence through the L-BFGS-B algorithm to minimize the objective function area, thereby obtaining the optimized lamp bead arrangement sequence, including:

[0081] Step S431: Calculate the initial illumination uniformity according to the initial arrangement position of the LED lamp beads;

[0082] Step S432: Call the objective function and optimize it in combination with the constraint conditions to obtain an optimized lamp bead arrangement sequence, wherein the optimization direction is to gradually optimize from one end of the arranged LED lamp beads to the center of symmetry, and the constraint conditions include: the position of the LED lamp beads does not exceed a preset range, and the spacing between the LED lamp beads increases successively from one end to the middle.

[0083] Through the above, the initial arrangement position of the LED lamp beads can be set to be evenly distributed. For each LED lamp bead, its distance to each point on the target plane is calculated. Based on the distance and angle, the illumination contribution of each LED lamp bead to the target plane is calculated. The illumination contributions of all LED lamp beads are accumulated to obtain the total illumination distribution of the target plane.

[0084] In the objective function, a function is called to ensure that the positions of the LED beads meet the constraints. First, bounds constraints are set, that is, the position of each LED bead is within a preset range, such as bounds = [(-led_line_length / 2, led_line_length / 2)for_in range(N)]; led_line_length is the total length of the LED array, and N is the number of LED beads. The position of each LED bead is ensured to be within the range [-led_line_length / 2, led_line_length / 2]. From one end to the middle, the spacing between the LED beads increases, as implemented in the enforce_spacing_constraints function. np.linspace is used to generate a spacing array from min_spacing to max_spacing, ensuring that the spacing is dense at the ends and sparse in the middle. The L-BFGS-B algorithm is called to optimize from one end of the array to the center of symmetry. The function is called to ensure that the optimized LED positions meet the constraints.

[0085] Specifically, the initial state is that the LED lamp beads are evenly distributed;

[0086] The L-BFGS-B algorithm gradually adjusts the position of the LEDs to minimize the objective function (negative uniformity). In each iteration, the enforce_spacing_constraints function is called to ensure that the LED positions meet the constraints. The optimization direction is to gradually optimize from one end toward the center of symmetry, ensuring that the spacing becomes denser at the ends and sparser in the middle. The final output is the optimized LED arrangement sequence.

[0087] In a further solution of the present application, the LED point distribution method further includes:

[0088] Step S51: Taking the target lamp arrangement sequence as input, the illumination contribution of each measurement point on the target plane is calculated and the total illumination distribution is calculated;

[0089] Step S52: Obtain the regional minimum value and the regional maximum value according to the illumination distribution matrix of the total illumination distribution, and verify the target lamp bead arrangement sequence by the ratio of the regional minimum value to the regional maximum value.

[0090] The optimized lamp arrangement sequence is used as input to calculate the illumination distribution of the target plane, the illumination contribution of each measurement point on the target plane, and the total illumination distribution matrix. As mentioned above, the total illumination distribution matrix is ​​a two-dimensional array that represents the illumination value of each measurement point on the target plane; the regional minimum value E_min and the regional maximum value E_max are extracted from the total illumination distribution matrix; according to the regional minimum value and the regional maximum value, the illumination uniformity is calculated, and it is judged whether the optimized illumination uniformity meets the requirements.

[0091] Specifically, in step S52, verifying the target lamp bead arrangement sequence by the ratio with the regional maximum value includes:

[0092] Step S521: Obtain the ratio of the minimum and maximum illuminance values ​​to calculate illuminance uniformity. When the illuminance uniformity is greater than a preset uniformity threshold, the verification is successful; and / or

[0093] Step S522: Obtain the regional average value based on the total illumination distribution. Based on a first ratio of the minimum value to the regional average value, and a second ratio of the maximum value to the regional average value, the verification is successful when the first ratio and the second ratio are within a preset uniformity range threshold.

[0094] The regional minimum value E_min and the regional maximum value E_max are extracted from the total illumination distribution matrix to calculate the illumination uniformity. The calculated illumination uniformity is compared with the preset uniformity threshold. For example, if the uniformity threshold is 0.5, it means that the uniformity must be greater than 0.8 to meet the requirement.

[0095] In addition, the regional average value is calculated from the total illumination distribution matrix (i.e., the single-point total illumination contribution of all measurement points is averaged), the ratio of the regional minimum value to the regional average value (first ratio), and the ratio of the maximum value to the regional average value (second ratio) are calculated; and it is determined whether the first ratio and the second ratio are within a preset uniformity range threshold, for example, within 0.8 to 1.2.

[0096] The above-mentioned step S521 and step S522 can be used as either one as the basis for verification, or can be set so that both conditions must be met at the same time for the verification to be considered successful.

[0097] Based on the above-mentioned LED point distribution method of the blackboard lamp, a specific embodiment is provided below:

[0098] At present, the mainstream size of blackboards is 4 meters (length) × 1.2 meters (height), the mainstream length of blackboard lamps is 1.2 meters, the emitting angle of LED lamp beads is 120 degrees (to facilitate large diffusion of light in both horizontal and vertical directions), and the standard requires that the support pole of the blackboard lamp be no more than 800mm away from the blackboard surface. The vertical illumination on the blackboard is usually adjusted by designing a reflective surface and (or) lens on the blackboard lamp. However, the horizontal illumination distribution of the blackboard conforms to the above analysis rules. Only the lamp bead arrangement length of 1190mm is considered, and the light guide kit is not considered. The plane illuminance at a distance of 780mm from the lamp beads is calculated. The target plane is 1400mm*400mm, and 35*9 measurement points are taken. The reason for choosing the target plane of 1400mm is that most of the blackboards are 4 meters long, and the number of blackboard lamps is usually 3. The minimum affected area of ​​the evenly distributed illumination is 4 meters ÷ 3 ≈ 1.33 meters. In order to ensure uniform illumination at the edge of the blackboard, the blackboard lamps on both sides will extend beyond a part of the edge of the blackboard.

[0099] The setting conditions are: single LED luminous intensity (I): 1 candela (cd); number of LEDs (N): 171;

[0100] Illumination angle (θ): 120 degrees; distance (d): 780mm; measurement plane: 1400mm*400mm, measurement point array: 35*9; lamp beads are arranged on a straight line within 1190mm; the distance between lamp beads is not less than 3mm.

[0101] Step 1: Establish a coordinate system

[0102] Arrange the LED lamp beads in a straight line in a symmetrical distribution. Let the position of the LED be xi, where i = 1, 2, ..., 171; the measurement point is located on the target plane 780 mm away from the LED lamp beads. Let the position of the measurement point be yj, where j = 1, 2, ..., 315.

[0103] Step 2: Calculate the impact of a single LED on the illumination of the measurement point

[0104] The illumination formula of a single LED lamp bead is:

[0105]

[0106] Where: Eij is the illuminance effect of the i-th LED on the j-th measurement point; φij is the angle between the light from the i-th LED to the j-th measurement point and the normal; d is the distance from the LED to the target plane.

[0107] Step 3: Calculate the total illumination at each point

[0108] For each measurement point j, the total illuminance Ej is the sum of the contributions of all LEDs to its illuminance:

[0109]

[0110] The calculation process is as follows: when the spacing between LED beads is fixed, the spacing is 1190 ÷ (171-1) = 7 mm; the illumination of the first measurement point LED position (y1 = 0): Assuming that the center of the LED bead is at x = 0, the position of the i-th LED is xi = (i-85) × 7 mm (because the LEDs are arranged symmetrically).

[0111] Distance calculation: The distance from the i-th LED to the first measurement point is: Angle calculation: Illumination calculation:

[0112] The total illumination at this point is:

[0113]

[0114] To obtain the position xi of the lamp bead when achieving optimal uniformity, nonlinear optimization is required. The L-BFGS-B algorithm is used for optimization. Since the calculation process involves a large amount of data and repeated calculations, only the calculation steps are listed here without the specific values.

[0115] Step 4: After running the program code, the optimized illumination uniformity and LED position xi will be obtained. Arranging the LED lamp beads in this position can optimize the illumination uniformity in the target plane. The optimized LED lamp bead position coordinates (Table 1: Optimized position coordinates of the lamp beads when the lamp beads are arranged on a straight line of 1190mm) and the optimized illumination distribution (Table 2: Illumination distribution of the lamp bead arrangement) are obtained. Figure 2 、 Figure 3 、 Figure 4 From the uniformity analysis, it can be seen that the arrangement position of the lamp beads on a straight line is optimized by the LED point distribution method adopted in this application, and programming calculation is performed to obtain the position of the lamp beads arranged nonlinearly on a straight line within the range of 1190 mm. The illumination uniformity at a distance of 780 mm and on a 1400mm*400mm plane is 20.9% higher than the illumination uniformity under the linear arrangement of the lamp beads. The program provided by the above-mentioned LED point distribution method has a parameter entry, and the corresponding parameters can be modified as needed for analysis and design, and a verification program is provided to verify the optimization results.

[0116] Before optimization calculation, LED lamp beads are arranged at equal distances, and the illumination uniformity is 0.43 ( Figure 5 ),and Figure 1 The results of DIAlux simulation of blackboard lamps arranged in equidistant straight lines are consistent. The optimized LED lamp beads are arranged in non-equidistant rows. The illumination uniformity optimized by the program is 0.52 ( Figure 4), which is 20.9% higher than that of the equidistant arrangement, and the optimized illumination curve is smoother ( Figure 6 ), the optimization effect is obvious, but the reason why it is not improved to a higher effect is that the lamp beads have a certain width and their positions cannot overlap, and the luminous intensity of the point light source itself is spherical, and the illumination cannot achieve a better distribution on the plane. Due to the distribution characteristics of the light intensity, the illumination uniformity within the range of the lamp can be adjusted to be close to 1, but the light intensity will decay rapidly outside the range of the lamp, and the point farthest from the edge of the lamp is the point with the smallest illumination. Because blackboard lamps are usually used in combination, they can adjust the illumination uniformity of the entire plane by using cross-illumination areas, and because the length of the blackboard is not fixed, there needs to be an adjustment margin. The measured plane in this calculation is 1400mm, and the distance between lamps has been considered, so the minimum plane illumination specified in this calculation can reach about 45% to 55% ( Figure 7 ), so that when the combination is used, the illumination of the overlapping area can be adjusted to around 100% and there is room for adjustment.

[0117] Table 1

[0118]

[0119] Table 2

[0120]

[0121] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are exemplary and are not to be construed as limiting the present invention. The present invention is provided with a parameter entry, and the parameters can be changed at will for analysis, optimization and verification. Those skilled in the art can change, modify, replace and modify the above embodiments within the scope of the present invention.

[0122] Based on the above-mentioned LED point distribution method based on blackboard lamp, the present application also provides a blackboard lamp (not shown in the figure), which includes a shell; a light source module, including several LED lamp beads, and the LED lamp beads are distributed according to the above-mentioned LED point distribution method.

[0123] The various technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification as long as such combination does not conflict.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still adjust the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these adjustments or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A LED point distribution method based on a blackboard lamp, characterized in that: include: Arrange a plurality of LED lamp beads on a preset straight line and in a centrally symmetrical distribution, with the position of each LED lamp bead being xi, establish a target plane located at a preset distance from the LED lamp bead, and preset a plurality of measurement points arranged in an array on the target plane, wherein the position of each measurement point is yj; Based on the illuminance contribution of each LED lamp bead to each measuring point, the single-point total illuminance contribution of each measuring point is ergodicly calculated to obtain the total illuminance distribution of the target plane; Obtaining a regional maximum value and a regional minimum value according to an illumination distribution matrix of the total illumination distribution, and calculating illumination uniformity by a ratio of the regional minimum value to the regional maximum value; The L-BFGS-B algorithm is used to perform optimization calculation with the goal of maximizing the illumination uniformity to obtain an optimized lamp bead arrangement sequence.

2. The LED point distribution method based on the blackboard lamp according to claim 1 is characterized in that: The contribution of each LED lamp bead to the illumination of each measurement point include: Among them, the illumination formula of each LED lamp bead is: Where: Eij is the illuminance contribution of the i-th LED to the j-th measurement point; φij is the angle between the light from LED bead xi to the measurement point yj and the normal; d is the distance from LED bead xi to the target plane.

3. The LED point distribution method based on the blackboard lamp according to claim 1 is characterized in that: The ergodic calculation of the single-point total illumination contribution of each measurement point to obtain the total illumination distribution of the target plane includes: For each measurement point yj, the sum of the illuminance contributions of all n LED lamp beads xi is calculated using the following formula to obtain the total illuminance contribution of a single point: The total illumination distribution is obtained by counting the single-point total illumination contributions of all measurement points yj.

4. The LED point distribution method based on the blackboard lamp according to claim 1 is characterized in that: The ergodic calculation of the single-point total illumination contribution of each measurement point to obtain the total illumination distribution of the target plane includes: For each measurement point yj, first select the LED lamp beads xu that can illuminate the measurement point yj, and sort the LED lamp beads xu from n1 to n2; For each measurement point yj, the sum of the illuminance contributions of the LED lamp beads xi that can illuminate the measurement point yj is calculated using the following formula to obtain the total illuminance contribution of the single point: The total illumination distribution is obtained by counting the single-point total illumination contributions of all measurement points yj.

5. The LED point distribution method based on the blackboard lamp according to claim 1 is characterized in that: The obtaining of a regional maximum value and a regional minimum value according to an illumination distribution matrix of the total illumination distribution, and calculating illumination uniformity by a ratio of the regional minimum value to the regional maximum value, includes: ergodicly selecting a plurality of sub-regions in the target plane, wherein each sub-region includes at least one measurement point; Calculate the average illuminance contribution of the single-point total illuminance of the measurement points contained in each sub-area; The illumination average values ​​are sorted to obtain the regional maximum value and the regional minimum value, and the ratio of the regional minimum value to the regional maximum value is used as the illumination uniformity.

6. The LED point distribution method based on the blackboard lamp according to claim 1 is characterized in that: The optimization calculation is performed by the L-BFGS-B algorithm with the goal of maximizing the illumination uniformity to obtain an optimized lamp bead arrangement sequence, including: The negative of illumination uniformity is used as the objective function; Define the constraints for LED lamp beads and provide the initial arrangement position when the LED lamp beads are equally spaced; The objective function, the initial arrangement position and the constraint conditions are input, and the lamp bead arrangement sequence is gradually searched through the L-BFGS-B algorithm to minimize the objective function area, thereby obtaining the optimized lamp bead arrangement sequence.

7. The LED point distribution method based on the blackboard lamp according to claim 6 is characterized in that: The objective function, the initial arrangement position and the constraint conditions are input, and the lamp bead arrangement sequence is gradually searched through the L-BFGS-B algorithm to minimize the objective function area, thereby obtaining the optimized lamp bead arrangement sequence, including: Calculate the initial illumination uniformity based on the initial arrangement position of the LED lamp beads; The objective function is called and optimized in combination with the constraint conditions to obtain an optimized lamp bead arrangement sequence, wherein the optimization direction is to gradually optimize from one end of the arranged LED lamp beads to the symmetry center, and the constraint conditions include: the position of the LED lamp beads does not exceed a preset range interval, and the spacing between the LED lamp beads increases successively from one end to the middle.

8. The LED point distribution method based on the blackboard lamp according to claim 1 is characterized in that: The LED point distribution method also includes: Taking the optimized lamp arrangement sequence as input, the illumination contribution of each measurement point on the target plane is calculated and the total illumination distribution is calculated; The regional maximum value and the regional minimum value are obtained according to the illumination distribution matrix of the total illumination distribution, and the optimized lamp bead arrangement sequence is verified by the regional minimum value of the regional maximum value.

9. The LED point distribution method based on the blackboard lamp according to claim 8 is characterized in that: The verification of the target lamp bead arrangement sequence by using the regional minimum value of the regional maximum value includes: Obtaining the ratio of the minimum value to the maximum value to calculate the illumination uniformity, and when the illumination uniformity is greater than a preset uniformity threshold, the verification is successful; and / or The regional average value is obtained according to the total illumination distribution. According to the first ratio of the minimum value to the regional average value and the second ratio of the maximum value to the regional average value, the verification is successful when the first ratio and the second ratio are within the preset uniformity range threshold.

10. A blackboard lamp, characterized in that: include: case; The light source module includes a plurality of LED lamp beads, wherein the LED lamp beads are distributed according to the LED point distribution method according to any one of claims 1 to 9.

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