Lighting device for special purposes to improve color rendering index and its design method

Abstract

An illumination apparatus for a special purpose, comprising: a primary illumination satisfying CRI > 90; and a secondary illumination suitable for a special purpose when used independently, wherein the secondary illumination is such that CRI < 80 when used independently, and, when used simultaneously with the primary illumination, the CRI of the primary illumination and the secondary illumination as a whole is greater than the CRI of the primary illumination alone. Preferably, the CRI of the primary illumination and the secondary illumination as a whole is greater than or equal to 94.

Description

[Technical Field]

[0001] The present invention relates to lighting systems, visible light illumination, devices adapted for specific treatments, control of light color, and control of light sources according to determined parameters. [Background technology]

[0002] The quality of color reproduction under artificial lighting is crucial in art, design, and retail. Accurate color judgment is essential for healthcare and wellness diagnostics. The most common method for evaluating color reproduction quality under light sources is the color rendering index (CRI). CRI measurement is summarized in the "Summary of the Invention" section and Non-Patent Literature 1.

[0003] This invention deals with special-purpose lighting. Special-purpose lighting typically refers to a light source that emits a predetermined relative energy distribution at selected wavelengths and can effectively perform a specific purpose on its own. "Special purpose" throughout this document refers to a light source whose emission spectral power density is 1) The light is restricted to emit light at a predetermined energy ratio across multiple wavelengths, or to emit light at a predetermined energy ratio across at least one pair of wavelengths. 2) CRI R alone a It must be a lighting system of <80 units. It is explained as referring to light. Lighting that emits light across the entire visible spectrum is CRI R a It is a general-purpose lighting fixture with a temperature of >80.

[0004] Lighting for special purposes can be designed in a variety of design variations. The claims made in this document are independent of the form factor, shape, or size of the lighting system. Some common forms of lighting are shown in the panels of Figure 1. Panels 1-4 of Figure 1A show examples of printed circuit boards (PCBs) with LEDs. Panels 5-8 of Figure 1A show examples of table lamps, portable lights, fixtures fixed to the ceiling or wall, or panel lights (commonly used in surgical rooms and art studios). Figures 1B and 1D-E show examples of using such PCB lights with devices similar to light bulbs (Figure 1B) or fluorescent lamps (Figure 1D-E). Figure 1C shows that lighting devices can consist of elements that can passively adjust the light output, such as diffusers or optical filters used as bulbs or lamp covers. Such diffusers or filters can also be used to adjust the emission spectrum of a particular device.

[0005] Practical examples of special-purpose lighting include light for inactivating medically relevant bacteria, molds, fungi, and viruses, or light sources to support plant growth and biological development, for example, in fish tanks and bacterial cultures. Plant growth lighting typically requires a specific ratio of blue (400-450 nm) to crimson (band around 660 nm) (Non-Patent Literature 2). Regardless of the scientific validity of the field of chromotherapy itself, various lightings for chromotherapy, designed to emit light of a specific color at a given frequency, should be considered “special-purpose” lighting. Germicidal light, whose emission spectrum falls within the visible wavelength spectrum, is similarly considered a “special-purpose” lighting system.

[0006] Lighting for special purposes generally has a low CRI value (i.e., CRI R a <50), and generally produce “unnatural light,” in contrast to general-purpose light, which is most commonly considered white and natural. When special-purpose lighting is used with a high CRI light source, the CRI index value of the high CRI light source is usually degraded overall. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] Kevin Houser, Michele Mossman, Kevin Smet & Lorne Whitehead (2016) Tutorial: Color Rendering and Its Applications in Lighting, LEUKOS, 12:1-2, 7-26, DOI: 10 .1080 / 15502724.2014.989802 [Non-Patent Document 2] Xu, Yingchao, Yongxiao Chang, Guanyu Chen, and Hongyi Lin. "The research on LED supplementary lighting system for plants." Optik 127, no. 18 (2016): 7193-72 01. DOI: 10.1016 / j.ijleo.2016.05.056 [Overview of the Initiative]

[0008] Special-purpose lighting is typically designed to operate independently. However, there are times when special-purpose lighting needs to be activated when other lighting is already in use. When such a need arises, the color rendering index of a white, high-color-rendering light source is disrupted, causing interference with the existing primary lighting system. However, as will be discussed later, according to the applicant's research, it is possible to design an additional, independent special-purpose light source that, when used alone, fulfills its primary purpose (i.e., disinfection or plant growth support) and, when used as secondary and complementary light, enhances at least one of the CRI indices of the primary light source.

[0009] The color rendering index (CRI) is a quantitative measure used to evaluate white light sources. Specifically, their color rendering properties are compared to an ideal white light source as a reference. The calculation of the CRI depends on the human photoreceptor sensitivity aggregated by the normalized human spectral sensitivity function (Figure 2A). Figure 2A shows the normalized spectral sensitivities of human cone cells. The peaks of the spectral sensitivities at short wavelengths ("S", 420 nm - 440 nm), medium wavelengths ("M", 530 nm - 540 nm), and long wavelengths ("L", 560 nm - 580 nm) are roughly distributed corresponding to the wavelengths of blue, red, and green. Three parameters corresponding to the stimulation levels of the three types of cone cells encode the human color sensation. The tristimulus values depend on the observer's visual field, and the CIE standard (colorimetric) observer eliminates this variable. The standard observer function represents the average human color response within the 2° fovea. The CIE color matching functions shown in Figure 2B are the numerical representations of the observer's color responses.

[0010] In the CIE1931 chromaticity diagram (Figure 3), ignoring the lightness of the color, only two coordinates can be used to encode the color perceived from the three receptors (S, M, L in Figure 2A) (gray and white are the same color but with different lightness). A light source that produces white light represents a series of coordinates that form a curve called the blackbody locus (the dashed curve). A light source with a high CRI occupies the area around the blackbody locus, and the CRI decreases as the distance of the x, y coordinates of the light source increases. The solid line that intersects the blackbody locus curve is the line of a certain equivalent blackbody temperature. Optimizing for a high CRI means minimizing the distance of the light source's x, y coordinates from the blackbody locus curve.

[0011] "Perfect" ideal white light is represented by the blackbody radiation spectrum when the correlated color temperature (CCT) is less than 5000K, and otherwise by the phase of the CIE standard illuminant D (daylight). The maximum CRI R aThe value is 100 (see the blackbody locus line in FIG. 3), and is assigned to the light source that renders a series of test color samples (TCS, see FIG. 2C for an example) in the same way as a test color sample is rendered under an ideal white light source. FIG. 2C shows an example of the spectral power distribution of three test color samples (the red tones (TCS08, TCS09) are responsible for indices R8 and R9 、 The blue tones are responsible for the CRI index R 12 (are responsible). The CRI index quantifies the similarity of the response of the human photoreceptors to the test color samples under the evaluated light source and an ideal blackbody light source.

[0012] The CRI value of a light source is calculated as the average of the first eight color rendering evaluation numbers R1 - R8, and is sometimes called CRI R a . Unless otherwise specified in this document, the terms "CRI value" and "CRI R a value" are used in the same meaning. The individual indices of CRI (at the time of writing this, there are a total of 16 indices. R a (the average of R1 - R8) and the individual indices R1 - R 15 ) are called by their names R i or ranges R i -R j (where i and j are numerical indices). The index R a is a general indicator of the quality of the approximation of natural white light. The indices Ri with i > 8 are used to evaluate the color reproduction quality of colors that are very important in specific fields. For example, R 15 is added to correspond to the reproduction of the color of Japanese skin. The number of indicators may increase, and the present invention is related to all of them.

[0013] Many other color rendering indices exist, each potentially offering specific advantages, and generally, improving color reproduction through the optimization of these alternative methods also improves the CRI. The present invention can be readily applied to other color rendering indexes, and the protections of the present invention described herein should include protection against the optimization of alternative color rendering indices that also increase the CRI.

[0014] The present invention discloses a method for designing a special-purpose light source that complements at least one other primary light source that is not a special-purpose light source and enhances at least one CRI index value of the primary light source.

[0015] The purpose of designing a light source using the method described is to obtain a light source that can 1) be used alone as a primary light source for a specific purpose, and 2) be used as a complementary secondary light source to an independent primary light source, while simultaneously improving any one or more CRI index values ​​of the primary light source.

[0016] Incidentally, when trying to obtain high-CRI white lighting (such as LEDs), anything above a CRI of 90 becomes expensive. For example, there are light sources that achieve a CRI of 94 or 95, but they come with an extremely high unit price. Therefore, another objective of this invention is to realize high-CRI lighting at a low cost.

[0017] Designing secondary special-purpose lighting that increases at least one of the CRI index values ​​of another primary light source is equivalent to designing a light source that applies specific constraints to its emission spectral density function. The spectral distribution of emission energy at a desired wavelength is determined by 1) the method of CRI calculation and 2) the emission spectral density function of the primary light source considered.

[0018] The lighting device of the present invention can be a secondary lighting device that improves the CRI of the primary lighting. For example, the lighting device is a special-purpose lighting device that is suitable for a special purpose when used alone. When used alone, the CRI is < 80. A primary light source separate from the aforementioned lighting device, when used simultaneously with a primary light source having a CRI > 90, makes the overall CRI of the lighting device and the primary light source greater than the CRI of the primary light source alone.

[0019] Furthermore, special-purpose lighting devices may include both primary and secondary lighting. For example, a special-purpose lighting device may have primary lighting that satisfies CRI > 90 and secondary lighting that is suitable for a special purpose when used alone. When used alone, the CRI is < 80. The system includes a secondary light source that, when used simultaneously with the primary light source, increases the overall CRI of the primary and secondary light sources compared to the CRI of the primary light source alone.

[0020] The CRI of the primary illumination should preferably be greater than 92.

[0021] In conventional lighting systems, using high-CRI (e.g., CRI > 90) primary lighting (white light, e.g., LED) in combination with other low-CRI secondary lighting typically resulted in a deterioration of the overall CRI. However, research by the inventors of this application has confirmed that using high-CRI primary lighting and low-CRI secondary lighting in combination with other low-CRI light sources under extremely limited conditions can achieve a higher CRI than primary lighting alone. Therefore, it is possible to use low-CRI secondary lighting for specific purposes while also providing high-CRI lighting. For example, accurately reproducing the colors of products is important in stores selling luxury goods. On the other hand, with the spread of COVID-19, sterilization by light is sometimes desired in stores. Under these demands, it has become possible to improve color reproduction while simultaneously achieving sterilization performance by increasing the CRI of the primary lighting. Furthermore, not limited to sterilization applications, even when using lighting for special purposes such as supporting plant growth, increasing the CRI of the primary lighting makes it possible to improve the color reproduction of plants. Furthermore, according to the present invention, the CRI of the primary illumination can be increased by the secondary illumination, eliminating the need to use an extremely expensive light source with a very high CRI as the primary illumination light source. This makes it possible to manufacture a lighting device with a high CRI at a low cost.

[0022] When the secondary illumination is used simultaneously with the primary illumination, it is desirable that the overall CRI of the primary and secondary illumination combined be 94 or higher.

[0023] The secondary illumination has a first peak in the wavelength range of 625 to 665 nm, and the spectral power at the first peak is the maximum spectral power of the primary illumination. nine It is desirable that the torque power be 0.1 to 0.9 times the torque power.

[0024] The secondary illumination has a second peak in the wavelength range of 400-410 nm, and the spectral power at the second peak is the maximum spectral power of the primary illumination. nine It is desirable that the torque power be 0.7 to 5 times greater.

[0025] The primary illumination may have a CRI < 93 when used alone. In this case, the cost of the primary illumination can be reduced.

[0026] It is desirable to further provide a control device that allows the user to switch between a state in which the primary and secondary lights are turned on simultaneously, and a state in which the primary lights are not turned on and only the secondary lights are turned on, either through user operation or under predetermined conditions.

[0027] The CRI R9 of the primary illumination may be 65 or less. In this case, the cost of primary illumination can be reduced.

[0028] The system may further include a control device that can change the output of the secondary lighting independently of the primary lighting. By changing the output of the secondary lighting, the CRI can be improved or the color tone can be adjusted according to the user's preference.

[0029] Another aspect of the present invention is a lighting device including a secondary light suitable for a special purpose when used alone, wherein when used simultaneously with other primary lights, the CRI of the secondary light and the primary light as a whole is greater than the CRI of the primary light alone. This design method uses a function PSD1 obtained by normalizing the power spectrum of the primary illumination by the maximum power spectrum, a function PSD2 obtained by normalizing the power spectrum of the first peak of the secondary illumination by the maximum power spectrum, A1 as a constant, A2 as a variable, and λ1 as the peak wavelength of the first peak, and the power spectrum function Y = A1PSD1 + A2PSD2 For a light source determined by λ1 and A2 within a predetermined range, CRI R a and CRI R i Calculate at least one of (any number from i=1 to 15), The CRI R a and CRI R iThe characteristics of the secondary illumination are determined by selecting λ1 and A2 such that at least one of them is greater than a predetermined threshold.

[0030] Furthermore, if the light source for the secondary illumination has a second peak, The power spectrum of the second peak of the secondary illumination is normalized by the maximum power spectrum, with PSD3 and A3 as variables, and the peak wavelength of the second peak is λ2, and the power spectrum function Y = A1PSD1 + A2PSD2 + A3PSD3 For a light source determined by λ1, λ2 and A2, A3 within a predetermined range, CRI R a and CRI R i Calculate at least one of (any number from i=1 to 15), The CRI R a and CRI R i The characteristics of the secondary illumination can be determined by selecting λ1, λ2 and A2, A3 such that at least one of them is greater than a predetermined threshold.

[0031] In the above method, one of A2 and A3 is set as a constant, and CRI R over a predetermined range of λ1, λ2 and A2, A3 a and CRI R i You may calculate at least one of (i=any number from 1 to 15).

[0032] By using a lighting device designed according to the method of the present invention, it is possible to improve the color reproduction characteristics of primary lighting while enjoying the primary purpose benefits of secondary lighting. For example, sanitized lights can be added to retail stores that require high CRI light sources without reducing the CRI while using both primary and secondary lights simultaneously.

[0033] The final spectral emission distribution may also depend on the availability of light-emitting elements (existing LEDs or other lamps). The method described here facilitates the design of light sources for special-purpose lighting using existing individual components. [Brief explanation of the drawing]

[0034] [Figure 1A] These are several examples of lighting devices in product form. [Figure 1B] This is an example of a lighting device shaped like a light bulb. [Figure 1C] This is an example of a lighting device shaped like a light bulb. [Figure 1D] This is an example of a lighting system equipped with a diffuser or similar device. [Figure 1E] This is an example of using fluorescent tubes for the lighting fixture. [Figure 2A] This is the normalized spectral sensitivity of human cone cells. [Figure 2B] This is the CIE standard observer color matching function. [Figure 2C] This is an example of the spectral power distribution of three test color samples used for CRI evaluation. [Figure 3] CIE1931 chromaticity diagram, high CRI region, and blackbody locus. [Figure 4A] Visualization of the objective function for maximizing Ra and R9CRI index values. [Figure 4B] Visualization of the objective function for maximizing the mean of the Ra+R9CRI index values. [Figure 5A] This shows the wavelength distribution of the primary and secondary light sources. [Figure 5B] Weighted combinations of primary and secondary light sources and the results of CRI optimization. [Modes for carrying out the invention]

[0035] The remainder of this document describes various possible embodiments of the lighting device for special purposes according to the present invention. First, several possible embodiments shown in Figure 1 are described, and then, with reference to the drawings and plots, a method for obtaining the working device of an example of use is described.

[0036] Examples are shown in Figure 1. Figure 1A shows a linear strip using LEDs as a light source. Example 1A is a variety of plate shapes in which the light source is embedded. Examples 5–8 show desk lamps, portable flashlights, ceiling / wall-mounted lighting fixtures, and panel lights. Any shape or form of such devices can be general-purpose or special-purpose lighting. The strips in panels A1–4 of Figure 1 function as printed circuit boards and can be flexible or solid. Such circuit boards can be embedded in housings similar to light bulbs or fluorescent lamps. Figure 1B shows other such possible forms, where it is common to place the light source in a device similar to an incandescent lamp. Figure 1C shows components of a possible light bulb in which a diffuser or filter is used to modulate the emission spectrum of the device. Figure 1D shows a cross-section of a diffuser tube (such as those used for fluorescent lamp tubes) with a linear strip of LEDs embedded in it. Figure 1E is a 3D view of the same object as Figure 1D.

[0037] The linear illumination in Figure 1E, in the form of a flexible or solid linear strip, is implemented with LEDs (light-emitting diodes) of a desired emission spectrum. The relative intensity of the light source is determined by the electrical circuit, particularly the relative distribution of current across each LED. This is achieved, in most cases, by a voltage divider or constant current source. Power to a single device can be supplied from one or more independent power supplies. The output of the powered device can be controlled by pulse-width modulation (PWM) dimming or by limiting the power supply voltage.

[0038] Other possible embodiments are shown in Figures 1A-E. Embodiments are not limited to devices using LEDs as light-emitting elements, but include any devices that emit visible radiation for the purpose of generating light, based on any technology including but not limited to semiconductor-based light-emitting, incandescent, and fluorescent sources.

[0039] Next, we will discuss special-purpose light sources with CRI-enhancing capabilities in possible use cases. One example scenario is when a retail store needs to add an additional secondary light source to its white light source A, such as a light source B that combines UV / crimson light for plant growth (crimson and blue) or disinfection (UV extended into the blue band). If the emission spectrum of the secondary light reaches visible wavelengths, such light can disrupt the color rendering index of the primary illumination. Adding special-purpose lighting is still possible if the emission spectrum of such secondary light B is designed to tune the combined emission of the two light sources A and B, and is designed to improve one or more color rendering index values. An increase in CRI can be achieved in several ways, by adding an additional light source and / or by blocking the emission of the primary light source at selected wavelengths using optical filters, diffusers, or shaders. A common element of the approaches described above is the objective of obtaining a specific emission spectral distribution.

[0040] In this example, primary light source A is considered to be white, high-CRI light with CRI > 92 (see hash bar in Figure 5B). Its emission spectrum is shown by the dashed line in Figure 5A. The design process for special-purpose illumination B described in this document begins with the requirements for emission power and emitted wavelength. In the example considered, the requirements are as follows: 1) Include crimson LEDs to support photosynthesis. 2) Include blue light with wavelengths that have disinfecting properties and support plant growth. 3) CRI of primary illumination a Increase the CRI index R i Increase i (where i > 0).

[0041] Here, the primary light source profile in the left panel of Figure 5A is the component's catalog value, while the primary light source profile in the right panel is the component's measured value. The luminescence intensity and wavelength of LEDs vary depending on the element's variability and temperature, so there is an error in the peak wavelength and its intensity. For example, the primary light source in Figure 5A has a peak around 450 nm, but its relative intensity differs between the left and right panels.

[0042] The most important step in light source design is the optimization problem. Our goal is to find pairs of wavelengths and their relative intensities. The objective function to optimize is R a and the mean of R9 or (R a The value is +R9) / 2.0. In this example, the primary light source has a high CRI, but the index values ​​of R8 and R9 are not optimal. Therefore, R a The greatest improvement is achieved by increasing the R8 value. Focusing on improving the R9 index value improves the R8 value, and further R a This can also be improved (see spectral characteristics of test color samples in Figure 2C). R8 benefits from light sources with wavelengths of blue (380-450nm) and red (>600nm). The optimization process has multiple variations of the objective function, as well as a set of free parameters. The free parameters represent the characteristics of the available components. Figure 4 shows CRI R using selected free parameters of 1) wavelength and 2) relative intensity of the light source. a This shows an example of CRI R9 optimization.

[0043] This problem can be formulated as a convex optimization problem. However, a simpler approach can also be used. This approach involves thoroughly searching the free parameter space and evaluating index values ​​for all combinations of parameter values. Assuming that the resulting CRI index values ​​produce a smooth function, the number of calculations can be reduced by evaluating index values ​​on a sparse grid, and a smooth result can be obtained by interpolation. This approach is particularly suitable when the choice of components for the final device assembly is limited.

[0044] The calculation of the CRI value involves conditional steps, and a thorough search allows for discrete or non-differentiable spectral emission functions. Visualizing and selecting parameters for the final design from the parameter space provides options for the weighting advantages of each parameter during optimization. The desired solution may lie in multiple cut regions of the parameter space. It may also be beneficial to use a different value from its neighborhood rather than the optimal value (the maximum or minimum value of the objective function).

[0045] R a Figure 4 shows a visualization of the objective function for maximizing the CRI index value of R9. Figure 4A shows CRI R a The CRI R9 evaluation is also shown. In this example, the objective function is the three normalized (max[PSD]=1) power spectral density functions PSD. i This is a weighted sum of (i=[1,2,3]). In other words, Y = A1PSD1 + A2PSD2 + A3PSD3 The grayscale heatmap shows the CRI(Y) index R for various combinations of white light and additional light sources. aThe values ​​of and R9 (left and right, respectively) are shown. In Figure 4A, the intensities of the white light source (PSD1) and one additional 405nm light source (PSD2) are fixed intensities (A1=constant, A2=constant). Then, the relative intensity (A3) of yet another additional light source and the CRI index value as a function of peak wavelength are visualized. The parameter space investigated is the peak wavelength range of 380–780nm and the relative intensity A3 range of 1–10. The weights A1–A3 are unitless multipliers that determine the relative intensity of the individual light sources that are ultimately mixed, and the values ​​determine the electrical or physical parameters of the physical components used to construct the actual light sources. The black area corresponds to a high color rendering index (solid black corresponds to a color rendering index of 100). This figure shows that combining primary and secondary light with various combinations of peak wavelength and relative intensity yields a CRI function with multiple maxima (darker shades of gray encode high values). Figure 4B shows the average of the two indices in Figure 4A. The two contour lines indicate the optimal region for high CRI. The solid line contour (darker area inside) represents the region where the average CRI of the two indices is 90, (R a The region where +R9) / 2.0 > 90 is enclosed. The white dashed outline encloses the region where the average of the two values ​​is greater than 93. Adding a light source with wavelength and relative intensity in the region enclosed by the white dashed line is R9 and R a This maximizes the CRI values ​​for both indices. This result suggests that setting the peak wavelength of the first peak of secondary illumination to around 645 nm (e.g., 620-670 nm or 625-665 nm) and setting the spectral power at the first peak to more than three times, preferably seven times, and even more preferably eight times, the combined CRI of primary and secondary illumination may be increased. In the above example, the secondary illumination has a second peak around 405 nm. Furthermore, while A2 was treated as a constant in the above example, the value of Y can be calculated over a wider range by treating A2 as a variable.

[0046] The contour lines in Figure 4B provide regions or optimal sets for secondary illumination for specific purposes. Using components with peak wavelengths within these contours allows for the design of intended, special-purpose lighting.

[0047] The left panel of Figure 5A shows the spectral power distributions of three independent light sources. The primary light source is characterized by its broadband spectrum (white primary general-purpose light) and plotted as a dashed line. For secondary special-purpose illumination, two additional narrowband light sources are considered. The dotted line shows the spectrum of the blue light, and the solid line shows the spectrum of the red light source. The right panel of Figure 5A shows two functions: the original white spectrum (dashed line corresponding to the dashed line in the left panel) and the spectrum of the special-purpose primary light source operating simultaneously. The special-purpose spectral function was obtained by the optimization described in the text of this specification. Next, using the spectral distribution functions of the primary and special-purpose illumination, Figure 5B was created. Panel 5B shows two sets of bars for comparison of the CRI of the two light sources operating together (blank white bars) with the CRI of the white primary light source only (bars filled with hash).

[0048] Based on the results in Figure 4, the applicant determined a light source with a peak wavelength of 660 nm as an easily available light source and optimized the value of A3. The result of optimizing the plant growth support and sanitizing lightning device in this example is two light-emitting elements. The first light-emitting element has a peak at 660 nm (normalized emission spectrum in the left panel of Figure 5A - solid lines for individual light sources), and the second light-emitting element has a peak at 405 nm (normalized emission spectrum in Figure 5A - dotted lines for individual light sources). The spectra shown in Figure 5 and used in the example optimization problem are examples of emission spectra of actual light sources (LEDs) available on the market. The white light source spectrum is from a white high CRI 3000K LED, which is an actual component (GW JCLPS2.CM(GEN 2)DURIS(registered trademark)E3 - normalized emission spectrum in Figure 5A - dashed lines in both the left and right panels).

[0049] In short, it was confirmed that a good CRI can be obtained when the secondary illumination has a power spectral distribution like the solid line in the right panel of Figure 5A. At this time, A2 was approximately 1.7 (ratio of the intensity of the 405nm peak to the broad peak around 620nm), and A3 was approximately 0.65 (ratio of the protrusion of the 660nm peak to the broad distribution of white light). For example, special-purpose illumination that achieves a good CRI has a secondary illumination with a first peak in the wavelength range of 625-665nm (preferably 650-665nm), and the spectral power at the first peak is the maximum spectrum of the primary illumination (white light). nine It is 0.1 to 0.9 times the Torr power. Furthermore, the secondary illumination has a second peak in the wavelength range of 400 to 410 nm, and the spectral power at the second peak is the maximum spectral power of the primary illumination (white light). nine This is 0.7 to 5 times the TorPower. A light source with a peak at 405 nm can have a relatively high intensity because the visible wavelength component is only a part of it. Also, as mentioned above, there are errors in the luminescence intensity and wavelength of LEDs during operation, so a certain error range should be included in the peak wavelength and its intensity.

[0050] Figure 5B shows the result of one possible thorough search of the parameter space shown in Figure 4. The CRI values ​​are shown in Figure 5B in two bar sets, and the hashed set shows the index of the original white light. CRI R in this example a It increased from 92.03 to 96.10, and the index R9 は It increased from 59.14 to 95.0. The bar graph in Figure 5B shows that other indices also increased similarly. Indices R8, R9, and R 12 The greatest improvement was achieved. In this example, the CRI R9 was 65 or less, and by adding secondary illumination that can improve the CRI R9, the CRI R a There is a possibility that this can also be improved.

[0051] In order to make the lighting device of the present invention practical, it is desirable that the lighting device be equipped with a control device. The control device may, for example, be able to change the output of the secondary lighting independently of the primary lighting. By changing the output of the secondary lighting, the CRI can be improved or the color tone can be adjusted according to the user's preference.

[0052] Furthermore, the control device may allow the user to switch between a state in which both primary and secondary lighting are turned on simultaneously, and a state in which the primary lighting is not turned on and only the secondary lighting is turned on, either through user operation or under predetermined conditions. The control device is, for example, a switching device. With such a control device, for example, during store hours, the primary and secondary lighting can be turned on simultaneously to achieve proper product display with high CRI and sterilization at the same time, and when the store is closed at night, only the secondary lighting can be turned on to continue sterilization. Of course, the control device may also be able to switch to a state in which the primary lighting is turned on and the secondary lighting is not turned on.

[0053] The examples and variations described herein and shown in the panel of Figure 1 are for illustrative purposes only and are not intended to limit. Many other arrangements of light-emitting elements, filters, or diffusers are possible without departing from the scope of the present invention. As described, it will be apparent to those skilled in the art that minor modifications can be made without significantly altering the operation.

Claims

1. White primary lighting satisfying CRI > 90, It is a secondary illumination source that is a narrowband light source and is not white. When used alone, the CRI is < 80. When used simultaneously with the primary illumination, the secondary illumination increases the overall CRI of the primary and secondary illumination compared to the CRI of the primary illumination alone. A lighting device characterized by comprising a control device that enables switching between a state in which the primary lighting and the secondary lighting are turned on simultaneously, and a state in which the primary lighting is not turned on and the secondary lighting is turned on, either by user operation or under predetermined conditions.

2. The lighting device according to claim 1, wherein when the secondary lighting is used simultaneously with the primary lighting, the overall CRI of the primary and secondary lighting is 94 or higher.

3. The illumination device according to claim 2, characterized in that the secondary illumination has a first peak in the wavelength range of 625 to 665 nm, and the spectral power at the first peak is 0.1 to 0.9 times the maximum spectral power of the primary illumination.

4. The illumination device according to claim 3, characterized in that the secondary illumination has a second peak in the wavelength range of 400 to 410 nm, and the spectral power at the second peak is 0.7 to 5 times the maximum spectral power of the primary illumination.

5. The lighting device according to claim 3 or 4, characterized in that the primary illumination has a CRI < 93 when used alone.

6. The lighting device according to any one of claims 1 to 5, characterized in that the secondary lighting, when used alone, is suitable for plant growth, biological development, or sterilization.

7. The CRI R of the primary illumination ９ The lighting device according to claim 3 or 4, characterized in that the value is 65 or less.

8. The lighting device according to any one of claims 1 to 7, characterized in that the control device can change the output of the secondary lighting independently of the primary lighting.

9. A method for designing a lighting device according to any one of claims 1 to 8, The function obtained by normalizing the power spectrum of the primary illumination by the maximum power spectrum is PSD. １ The function obtained by normalizing the power spectrum of the first peak of the secondary illumination with the maximum power spectrum is PSD. ２ A １ Let A be a constant. ２ Let be a variable, and the peak wavelength of the first peak be λ １ The power spectral function 9=A １ 030 １ +A ２ 030 ２ For a light source determined by λ within a predetermined range １ and A ２ Throughout, CRI R ａ and CRI R ｉ Calculate at least one of (i = any number from 1 to 15), The CRI R ａ and CRI R ｉ At least one of λ is greater than a predetermined threshold １ and A ２ The characteristics of the secondary illumination are determined by selecting the appropriate option. A design method for lighting devices characterized by the following.

10. When the light source for the secondary illumination has a second peak, The function obtained by normalizing the power spectrum of the second peak of the secondary illumination by the maximum power spectrum is PSD. ３ A ３ Let be a variable, and the peak wavelength of the second peak be λ ２ The power spectral function 9=A １ 030 １ +A ２ 030 ２ +A ３ 030 ３ For a light source determined by λ within a predetermined range １ , λ ２ and A ２ , A ３ Throughout, CRI R ａ and CRI R ｉ Calculate at least one of (i = any number from 1 to 15), The CRI R ａ and CRI R ｉ At least one of λ is greater than a predetermined threshold １ , λ ２ and A ２ , A ３ The characteristics of the secondary illumination are determined by selecting the appropriate option. A method for designing a lighting device according to claim 9, characterized by the above.

11. A ２ , A ３ Let one of them be a constant, and the λ within a predetermined range １ , λ ２ and A ２ , A ３ Throughout, CRI R ａ and CRI R ｉ The method for designing a lighting device according to claim 10, characterized by calculating at least one of (i = any number from 1 to 15).

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