Optical component for a luminaire
By incorporating slits and grids between lens elements, the problem of existing illuminators failing to meet glare levels and brightness requirements is solved, resulting in a highly efficient and economical illuminator design with an L65 value reduced by approximately 40%.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SIGNIFY HOLDING BV
- Filing Date
- 2022-03-04
- Publication Date
- 2026-07-21
AI Technical Summary
Existing illuminators struggle to simultaneously meet the requirements of a glare rating (UGR) of no more than 19 and a luminance of no more than 3000 cd/m2 above the lowest point. This is especially true for illuminators that combine diffusers and microlens optical plates, where efficiency is typically below 70%. While the combination of a lens plate and a diffuser may have an efficiency of over 80%, it is also more expensive.
A slit with an elongated shape and a tapered cross-section in a plane perpendicular to the support plate is provided between the lens elements. Combined with a grid, a grid mesh is formed. The slit and grid are used to reduce unwanted light guidance. Polycarbonate (PC) material is preferably used to improve mechanical reliability and reduce Fresnel reflection effects.
By using slits and grilles, the L65 value is significantly reduced to meet the brightness standards required for office lighting, while maintaining high efficiency and reducing costs. The L65 value is reduced by approximately 40%.
Smart Images
Figure CN117120770B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an optical component for a luminaire, such as an LED (light-emitting diode) luminaire. The invention also relates to a luminaire incorporating such an optical component. Background Technology
[0002] Lighting fixtures, especially those used in office environments, must meet certain requirements related to glare. According to the International Commission on Illumination (CIE), glare is defined as: "visual conditions in which there is excessive contrast or inappropriate distribution of light sources that interferes with the observer's ability to distinguish details and objects."
[0003] Glare within the field of view can be measured using a luminance meter. A luminance meter is a photometric device used to measure the luminous intensity (i.e., luminance) of light traveling in a given direction within a specific solid angle per unit area. Glare can be calculated based on the measured luminance data.
[0004] The CIE recommends the Uniform Glare Scale (UGR) as a quantitative measure of glare. The UGR is calculated using a formula that takes into account several factors that may contribute to glare caused by an illuminator, such as the illuminance of the illuminator, the value of the background luminance, the solid angle of the illuminator as seen by the viewer, and the likelihood of glare, as expressed by the Guth position index (sometimes also referred to as the probability of visual comfort).
[0005] For lighting fixtures that fully meet office requirements, the first requirement is that the luminance (UGR) should not exceed 19. The second requirement is that the luminance at a 65-degree angle above the lowest point (L65) and at higher angles should not exceed 3000 cd / m². 2 Preferably, meeting these requirements should not come at the expense of reduced efficiency.
[0006] A first example of an illuminator that meets the aforementioned requirements regarding glare includes: a plate with multiple light sources (such as LEDs); a diffuser arranged to receive light emitted from the multiple light sources; and a microlens optics (MLO) plate. The purpose of the diffuser is to make the individual light sources less visible, and the purpose of the MLO plate is to prevent the light beam from leaving the illuminator at a relatively shallow angle. In operation, the illuminator provides a relatively uniform and collimated light output. However, the overall efficiency is typically below 70%, and the MLO plate is relatively expensive.
[0007] A second example of an illuminator that meets the above requirements regarding glare includes: a plate with multiple light sources (such as LEDs); an optical component in the form of a lens plate having multiple lens elements for receiving light emitted by the multiple light sources; and a diffuser (such as a frosted cover). The combination of the lens plate and the diffuser typically results in a total efficiency of over 80%.
[0008] EP-3696591 discloses a monolithic lens plate having a first lens and a second lens located on a substrate, and a slit located between the first lens and the second lens and having a slit bottom. In a plane perpendicular to the substrate, the first lens has a cross-section having a first top surface with a first shape, the second lens has a cross-section having a second top surface with a second shape, and the slit has a cross-section having: a first wall intersecting the first top surface at a first point; and a second wall intersecting the second top surface at a second point. The distance between the first point and the second point is not zero. The first shape is defined by a first mathematical function, and the second shape is defined by a second mathematical function. The intersection of the first mathematical function and the second mathematical function is located between the first point and the second point and above the bottom of the slit. Summary of the Invention
[0009] It has been found that for illuminators that combine diffusers and MLO plates, and even for illuminators that combine lens plates and diffusers, it is still difficult to meet the L65 requirements.
[0010] The purpose of this invention is to overcome or at least mitigate the above-mentioned problems and to provide improved optical components.
[0011] According to a first aspect of the invention, this and other objectives are achieved by an optical component for an illuminator, the optical component comprising: a carrier plate having an upper surface and a lower surface; and a plurality of lens elements disposed on the upper surface, each pair of adjacent lens elements having an intermediate region, wherein in each intermediate region, the carrier plate includes a slit having an elongated shape having a long axis parallel to a plane of the carrier plate.
[0012] The object of the present invention is achieved by an optical component according to a first aspect of the invention, which provides slits between the lens elements. It is not intended to be theoretically constrained, but it is believed that the difficulty in meeting the L65 requirement stems from the light guided within the optical component, particularly the light guided within the carrier plate of the optical component. The slits between the lens elements serve to reduce any undesirable light guidance within the optical component. The slits primarily reduce the luminous flux at a relatively wide angle to the lowest point, and the slits have almost no effect on the overall efficiency of the illuminator. As will be shown below, optical simulations show that L65 is reduced by at least 10%.
[0013] Each slit can extend completely through the support plate from the top surface to the bottom surface.
[0014] Each slit has a cross-section in a plane perpendicular to its major axis. The cross-section can be rectangular or it can be shaped as an isosceles trapezoid. In the latter case, the cross-section has two opposing tapered sides. A slit with such a cross-section can also be referred to as a V-groove. The two opposing tapered sides have an included angle. The included angle can have any value, such as 10 degrees, 20 degrees, or 60 degrees. A larger angle (e.g., 60 degrees or more) may be advantageous compared to a smaller angle (e.g., 10 degrees (or less)) because less light flux passes through the slit (due to more light being reflected by total internal reflection).
[0015] When the slit cross-section has two opposing tapered sides, each of the two opposing tapered sides may have a stepped surface profile. Optical simulations have shown that, provided there is sufficient space between the lens elements, a slit in the form of a V-groove with a stepped surface profile is preferred.
[0016] The optical components may also include multiple grids, and each grid can be positioned within a slit. The slits, in turn, offer a further advantage because they allow for easy placement of grids within them. The presence of grids is beneficial for meeting office requirements. The individual grids can be interconnected to form a grid mesh.
[0017] For every two adjacent lens elements, the intermediate region has a first width, and the slit has a second width, each of which is measured in the direction connecting the centers of the two adjacent lens elements. The second width (i.e., the width of the slit) can be greater than the first width (i.e., the width of the intermediate region), such that the slit (intentionally) cuts off a portion of each of the two adjacent lens elements. This makes the light distribution in the C90 plane slightly narrower.
[0018] According to a second aspect of the invention, this objective is achieved by an illuminator comprising a light engine having a plate with multiple light sources and an optical component according to a first aspect of the invention. The optical component is arranged to receive light emitted by the light engine.
[0019] The light engine and optical components can be housed within a housing. The housing may have a light-emitting window, and the illuminator may also have a light-transmitting cover disposed at the light-emitting window.
[0020] The light-transmitting cover can be a diffuser or a transmissive cover, such as a transparent cover.
[0021] Optical components can be attached to the light engine via snap-fit connections. Attached Figure Description
[0022] Embodiments of the invention will now be described by way of example only with reference to the schematic accompanying drawings, in which corresponding reference numerals indicate corresponding parts, and wherein:
[0023] Figure 1 The illuminator is shown;
[0024] Figure 2 a and Figure 2 b respectively showed Figure 1 Enlarged view and cross-sectional view of the illuminator;
[0025] Figure 3 a and 3b show top and exploded perspective views of the optical components and light engine;
[0026] Figure 4 a to Figure 4 Figure d shows a top view and an alternative cross-sectional view of the optical component;
[0027] Figure 5 A perspective view of the grid mesh is shown; and
[0028] Figure 6 A perspective view of the optical components is shown.
[0029] The illustrative illustrations are not necessarily drawn to scale. Detailed Implementation
[0030] Figure 1 A luminaire 100 is shown having a housing 110 extending along axis A, which can be suspended from the ceiling by means of a suspension cable 130. The housing 110 of the luminaire 100 has a light-emitting window, in which a light-transmitting cover 120 is provided. The light-transmitting cover 120 can be a diffuser, such as a frosted cover. Alternatively, the light-transmitting cover 120 can be a transmissive cover, such as a transparent cover.
[0031] Figure 2 The same illuminator 100 is shown, but the end cap has now been removed to allow observation of the interior of the housing 110.
[0032] Figure 2 View b shows a cross-section of the illuminator 100 perpendicular to axis A. This cross-sectional view also shows the optical components 140 and the light engine 150 located within the housing 110. In operation, the optical components 140 receive light emitted by the light engine 150. The light then exits the illuminator 100 through the light exit window of the housing 110 and through the light-transmitting cover 120.
[0033] Figure 3A top view of optical component 140 is shown. Optical component 140 has a carrier plate 141 and a plurality of lens elements 142 arranged in a linear array on the carrier plate 141. The linear array is oriented along axis B of optical component 140. The carrier plate 141 and the lens elements 142 may be an integral part of a single piece (or a single sheet) of optical component 140.
[0034] Figure 3 View b shows an exploded perspective view of the optical component 140, indicating that the lens element 142 is disposed on the upper surface 141a of the support plate 141. The support plate 141 has a lower surface 141b opposite to the upper surface 141a. The lower surface 141b faces the light engine 150. The light engine 150 includes a plate 151 having a light source 152. When viewed in the direction from the light engine 150 to the optical component 140, each light source 152 is aligned with the lens element 142.
[0035] In operation, optical component 140 receives light emitted by light engine 150. The emitted light first strikes the lower surface 141b, where it can be refracted or reflected. The refracted light enters optical component 140. Reflected light may also enter optical component 140, for example, after being reflected back by light engine 150 toward lower surface 141b. Light that has entered optical component 140 may exit optical component 140 by refraction at upper surface 141a or at lens element 142. Light can also be guided within optical component 140 by total internal reflection. This portion of the light (i.e., the portion of the light emitted by the light source that travels a certain distance within optical component 140 after entering optical component 140) may exit optical component 140 at a relatively high angle relative to the normal of upper surface 141a, which in turn will result in a brightness value at an angle of 65 degrees above the lowest point that does not meet office requirements.
[0036] exist Figure 3 In b, lens element 142 is a convex lens, and light source 152 is an LED. Optical component 140 can be attached to light engine 150 via a snap-fit connection. In other words, optical component 140 can be a snap-fit component.
[0037] The carrier plate 141 and lens element 142 of the optical component 140 can be made of polymethyl methacrylate (PMMA) or polycarbonate (PC). PC is preferred over PMMA when the optical component is a snap-fit part. This is because PMMA is a relatively brittle material, and PC has better mechanical reliability compared to PMMA. The advantage of the optical component being a snap-fit part is that it allows for a simplified construction. Another advantage of using PC instead of PMMA is that PC has lower flammability than PMMA.
[0038] PMMA has a refractive index of 1.492, while PC has a refractive index of 1.596. Because PC has a higher refractive index than PMMA, the shape of a PC lens element must be adjusted to maintain a similar light distribution compared to a PMMA lens element. The shape of the lens element is determined by its inner and outer surfaces. Total Fresnel reflection from the PC surface is approximately 5%, while it is approximately 4% from the PMMA surface. Due to the difficulty in controlling the amount of light reflected from these Fresnel reflections, the L65 value of a PC lens element is typically about 25% higher than that of a similarly shaped PMMA lens element.
[0039] Simulations have shown that the increased L65 value is caused by light from a light source that undergoes Fresnel reflection before passing through a lens element positioned away from the light source.
[0040] Providing a grid between adjacent lens elements helps reduce the L65 value. For example, when a grid with a height of 1.5 mm and a reflectivity of 5% are used in conjunction with a PC lens element, the L65 value increases from 3512 cd / m². 2 Reduced to 2735 cd / m 2 This will satisfy the requirement that the L65 value is 3000 cd / m 2 Or smaller office requirements. Grilles can be provided in the form of a grid mesh. However, this may not be preferred from a mechanical point of view, as such a grid mesh is relatively flexible and difficult to position and assemble. When the grille is manufactured to be thicker and / or taller, the effectiveness and width of light distribution are reduced, and visual artifacts occur.
[0041] The inventors have discovered that by providing a slit in each intermediate region between two adjacent lens elements, it is also possible to achieve the desired reduction of the L65 value to a value that falls within the range required by the office.
[0042] Figure 4 A top view of a portion of an optical component 140 is shown. The optical component 140 has three lens elements 142a, 142b, and 142c. Intermediate regions 143 are located between adjacent lens elements 142a and 142b, and between adjacent lens elements 142b and 142c. Each intermediate region 143 includes a slit 144. Each slit 144 has an elongated shape with a long axis. An elongated shape is defined as a shape having a length and a width, wherein the aspect ratio of the length and width is at least 2, such as at least 5 or at least 10. The long axis is oriented in a direction parallel to the plane of the support plate 141 and perpendicular to line B that connects the centers of two adjacent lens elements.
[0043] Figure 4View b shows a cross-sectional side view of the optical component 140. In this view, it can be seen that each slit 144 has a cross-section in a plane perpendicular to its long axis, wherein the cross-section is shaped with two opposing sides that taper from the lower surface 141b of the support plate 141 to the upper surface 141a of the support plate 141. Furthermore, the two opposing tapered sides have an included angle of approximately 60 degrees. Each slit 144 extends completely through the support plate 141, from the upper surface 141a to the lower surface 141b. In other words, each slit 144 is a through-hole. At the lower surface 141b, the support plate 141 has a cavity or recess, each cavity or recess for accommodating a light source.
[0044] Figure 4 c shows an alternative cross-sectional side view of the optical component 140. Here, for each slit 144, each of the two opposing tapered sides has a stepped surface profile.
[0045] Figure 4 d again showed Figure 4 The image shows a cross-sectional side view, but at this point, the optical component 140 also includes multiple gratings 145. Each grating 145 is disposed in the slit 144 and may have a reflectivity of 5% (or less).
[0046] Figure 4 The stepped surface profile shown in c and 4d also helps reduce any unwanted light guidance in the carrier plate of optical component 140 in order to meet the L65 requirement. Optical simulations have shown a reduction of approximately 10% in the L65 value.
[0047] Furthermore, a stepped surface profile can be used as an mounting device for the grille 145. Note that the grille can also be positioned in slits of different shapes, but slits in the form of tapered grooves with a stepped surface profile allow for convenient placement of the grille. Placing the grille within the slit also helps meet the L65 requirement. Optical simulations have shown a further reduction of approximately 30% in the L65 value. The combination of a slit with a stepped surface profile and a grille placed within the slit provides an overall reduction of approximately 40% in the L65 value.
[0048] like Figure 5 As shown, multiple grilles 145 can be interconnected to form a grille grid 146. Because the grilles 145 are accommodated by the slits 144, the grille grid 146 can be easily mounted onto the optical component 140.
[0049] Figure 4 b to Figure 4 The slit 144 shown in d has a tapered cross section, but other shapes can also be used. Figure 4 b to Figure 4The slit 144 shown in diagram d extends completely through the support plate 141. In other words, the slit 144 is a through hole. Alternatively, the slit may extend only partially through the support plate from the lower surface toward the upper surface, or vice versa. In this case, the slit is a blind hole.
[0050] The function of a slit is to reduce the luminous flux transmitted along the carrier plate. This function is achieved by total internal reflection, which blocks light guidance within the carrier plate. For this purpose, each slit has a cross-section in a plane perpendicular to its long axis. The cross-section has a width and a depth, and it can have any shape. The ratio of the width to the depth defines the aspect ratio of the slit. The aspect ratio can have any value to achieve the effect of reducing the luminous flux transmitted along the carrier plate. From a manufacturing point of view, certain aspect ratios may be preferred. For example, if the optical component is to be manufactured using a molding process, certain constraints can be imposed regarding the aspect ratio of the slit.
[0051] When the lens elements on the carrier plate are relatively densely packed, the intermediate regions between adjacent lens elements will be relatively narrow, providing available space for slits in these intermediate regions. In this case, the width of the slit can be greater than the width of the intermediate regions (this width is a dimension measured in a direction connecting the centers of the lens elements immediately adjacent to the intermediate regions and the slits). This means that each slit intentionally cuts off a portion of each of the two adjacent lens elements. This has the effect of narrowing the light distribution in the C90 plane. Figure 6 The configuration shown is as follows: Figure 6 A perspective top view of the optical component 140 is shown. The lens elements 142 are so densely packed that the width of the central region is close to zero. Slits 144 extend from the upper surface of the lens elements 142 to the lower surface. The width of the slits 144 is greater than the width of the central region between adjacent lens elements 142, and each slit 144 cuts a portion of each of the two adjacent lens elements 142. Note that the dashed lines drawn in the lens elements 142 are only for showing the (convex) curved surface of the outer surface of the lens elements 142.
[0052] exist Figure 6 In this configuration, each slit 144 has a cross-section in a plane perpendicular to its long axis, wherein the shape of the cross-section has two opposing sides that taper from the upper surface of the support plate to the lower surface of the support plate. The limited available space between adjacent lens elements 142 prevents the provision of a stepped surface profile in the two opposing tapered sides and also limits the included angle between the two opposing tapered sides to approximately 20 degrees.
[0053] exist Figure 4 From b to 4d, the slit 144 gradually narrows from the upper surface 141a to the lower surface 141b. Figure 6In this configuration, slit 144 is tapered from the lower surface to the upper surface. The preferred tapered orientation may depend on parameters such as the shape of the lens element 142, the desired light distribution, and the light source used (e.g., an LED package).
[0054] It should be noted that the above embodiments are illustrative rather than limiting of the invention, and those skilled in the art will be able to devise many alternative embodiments without departing from the scope of the appended claims. Any reference numerals placed between parentheses in the claims should not be construed as limiting the claims. The use of the verb "comprising" and its variations does not exclude the presence of elements or steps other than those stated in the claims. The articles "a" and "an" preceding an element do not exclude the presence of a plurality of such elements. In device claims enumerating several devices, two or more of these devices may be implemented by an identical item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used advantageously.
[0055] The various aspects discussed in this patent can be combined to provide additional advantages. Furthermore, those skilled in the art will understand that the embodiments can be combined, and more than two embodiments can be combined.
Claims
1. An optical component (140) for an illuminator (100), the optical component (140) comprising: A support plate (141) having an upper surface (141a) and a lower surface (141b); and a plurality of lens elements (142) disposed on the upper surface (141a), each pair of adjacent lens elements (142) having an intermediate region (143), In each intermediate region (143), the support plate (141) includes a slit (144) having an elongated shape and a long axis parallel to the plane of the support plate (141). Each slit (144) has a cross-section in a plane perpendicular to the long axis, the cross-section having two opposing tapered sides, and Each of the two opposing tapered sides has a stepped surface profile.
2. The optical component (140) according to claim 1, wherein, Each slit (144) extends completely through the support plate (141) from the upper surface (141a) to the lower surface (141b).
3. The optical component (140) according to any one of claims 1-2, wherein the two opposing conical sides have an included angle of at least 60 degrees.
4. The optical component (140) according to any one of claims 1-2, wherein, The optical component (140) also includes a plurality of grids (145), each grid (145) being disposed in a slit (144).
5. The optical component (140) according to claim 4, wherein, Each grid (145) is interconnected to form a grid mesh (146).
6. The optical component (140) according to any one of claims 1-2, wherein, For every two adjacent lens elements (142), the intermediate region (143) has a first width, and the slit (144) has a second width, wherein each of the first width and the second width is measured in a direction connecting the centers of the two adjacent lens elements (142), and wherein the second width is greater than the first width, such that the slit (144) cuts a portion of each of the two adjacent lens elements (142).
7. A lighting device (100), comprising: A light engine (150) having a plate (151) with multiple light sources (152); as well as The optical component (140) according to any one of claims 1-2, The optical component (140) is arranged to receive light emitted by the light engine (150).
8. The illuminator (100) according to claim 7, wherein, The light engine (150) and the optical component (140) are disposed in a housing (110), wherein the housing (110) has a light-emitting window, and wherein the illuminator (100) also has a light-transmitting cover (120) disposed at the light-emitting window.
9. The illuminator (100) according to claim 8, wherein the light-transmitting cover (120) is a diffuser.
10. The illuminator (100) according to claim 7, wherein, The optical component (140) is attached to the optical engine (150) via a snap-fit connection.