Lens unit

Abstract

A lens unit for directing light generated by a light source of a luminaire includes a refractive portion and a total internal reflection portion. The total internal reflection portion is arranged in an L shape.

Description

Field of the Invention

[0001] The present invention relates to the field of lamps, and more particularly to a lens unit for such lamps. Background Art

[0002] Lamps are increasingly being used. Such lamps utilize one or more optical systems or elements to control the emission of light output therefrom. A typical form of an optical system is a lens unit, which controls the direction, spread, and uniformity of the light output by the lamp.

[0003] There are a variety of different scenarios in which lamps can be used. In certain environments and situations, for example, in outdoor environments, the lamp can only be positioned at the corner of the area to be illuminated. There has been a long-felt desire to improve the effectiveness of such lamps.

[0004] EP 3483500A1 discloses an optical element for a lighting fixture.

[0005] US10330902B1 discloses an illumination optical device as a collimator lens.

[0006] EP 2871411A1 discloses an optical element for a lamp and a corresponding lamp. Summary of the Invention

[0007] The present invention is defined by the claims.

[0008] According to an example of one aspect of the present invention, there is provided a lens unit for a lamp including a light source. The lens unit has an axis perpendicular to the plane in which the light source is located.

[0009] The lens unit includes: a light source cavity for receiving light from the light source, the light source being locatable in the light source cavity; a refraction portion spaced apart from the plane for refracting the light received from the light source; a total internal reflection portion spaced apart from the plane, including a first sub-portion and a second sub-portion, which are angled relative to each other so as to form an L-shape when viewed in a direction perpendicular to the plane.

[0010] The first sub-portion and the second sub-portion of the total internal reflection portion each include a first surface facing the refraction portion and a second surface facing away from the refraction portion. The second surface is inclined relative to the plane to reflect the light received from the light source by total internal reflection.

[0011] The second surface includes a proximal end and a distal end, the proximal end being positioned closer to the light source cavity than the distal end. In a cross-section passing through the axis, the distance between the proximal end and the axis is greater than the distance between the distal end and the axis.

[0012] The use of the light source cavity improves the compactness (e.g., reduces the thickness) of the lamp incorporating such a lens unit.

[0013] Therefore, the total internal reflection portion is considered to reflect the light received from the light source. This helps to direct the light towards an overall direction away from the total internal reflection portion, providing a brighter and more uniform light distribution in the direction away from the total internal reflection portion.

[0014] Obviously, the L-shape of the total internal reflection unit means that the light output by the light source and not directed towards the total internal reflection portion (or not refracted towards it through the refraction portion) is not received by the total internal reflection unit.

[0015] For example, the L-shape can be positioned at the corner of the area to be irradiated. The proposed method includes the light that would otherwise escape within the area to be irradiated by using the total internal reflection unit, thereby increasing the amount of light directed from the corner to the area to be irradiated. In other words, the arrangement and configuration of the total internal reflection portion reduce the light leakage in the direction away from the desired area to be irradiated. Therefore, the proposed method provides greater irradiation of the area to be irradiated and improves the uniformity of the light.

[0016] The first sub-portion and the second sub-portion can be substantially perpendicular to each other. For example, the first sub-portion and the second sub-portion can be at a right angle to each other.

[0017] Preferably, the first sub-portion and the second sub-portion meet at the corner position. This method reduces the possibility that the light emitted by the light source and directed away from the refraction portion cannot enter the total internal reflection portion and be reflected back to the desired area to be irradiated.

[0018] In some examples, the lens unit is configured such that the height of each of the first and second sub-portion decreases as the distance from the corner position increases. This improves the smoothness or gradient of the light output through the lens unit, thereby reducing or alleviating any sudden cut-off in the light beam output by the lens unit.

[0019] Preferably, the lens unit is formed from a uniform block of material. This avoids or reduces any accidental redirection (e.g., reflection / refraction) at any interface between different parts of the lens unit, as well as improves the simplicity and cost of manufacturing the lens unit.

[0020] Examples of suitable materials for forming the lens unit include plastics such as polycarbonate or PMMA, or glass.

[0021] Preferably, the height of the light source cavity is greater than the (maximum) height of the light source. This reduces the possibility of mechanical coupling or interference between the lens unit and the light source.

[0022] The light source cavity can form part of a larger cavity of the lens unit. For example, the larger cavity can also include an optical cavity that receives the light emitted by the light source (positioned within the light source cavity). The height of the light source cavity can be greater than the height of the light source itself. This height can be measured in a direction parallel to the axis.

[0023] There is also provided a lighting fixture, comprising any lens unit described herein; and a light source configured to generate light, wherein the light source is positioned to emit light into the lens unit.

[0024] In some examples, the light source is positioned to be partially surrounded by a volume defined by an L-shape formed by a first sub-part and a second sub-part of the total internal reflection portion of the lens unit. Specifically, if there is a cavity, the light source can be positioned within the cavity of the lens unit.

[0025] The present invention also provides a lens plate, which comprises an array of lens units as described herein / above. The lens plate can be formed from a homogeneous block of material.

[0026] Preferably, the array of lens units is arranged in a regular grid. This approach improves the uniformity of the light output through the lens plate.

[0027] The array of lens units preferably comprises no less than five lens units, for example no less than nine lens units.

[0028] The present invention also provides a lighting fixture, which comprises the lens plate as described in any one of the above; and a corresponding light source for each lens unit of the lens plate, which is configured to generate light, and is positioned within the light source cavity of the lens unit and is positioned to emit light into the lens unit. Thus, the number of light sources can be the same as the number of lens units of the lens plate.

[0029] In some examples, for each lens unit, the corresponding light source is located within a volume that is positioned to be partially surrounded by an L-shape formed by a first sub-part and a second sub-part of the total internal reflection portion of the lens unit. Specifically, if there is a cavity, the light source can be positioned inside the cavity of the lens unit.

[0030] These and other aspects of the present invention will become apparent from the embodiments described hereinafter and will be elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] For a better understanding of the present invention and to more clearly show how to implement the present invention, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0032] Figure 1 A lens unit is shown;

[0033] Figure 2 A part of a lighting fixture including a lens unit is shown in a sectional view;

[0034] Figure 3 A cross-sectional view of a cavity in the lens unit of the lighting fixture is shown;

[0035] Figure 4 Shows a cross-sectional view of a luminaire;

[0036] Figure 5 Shows another cross-sectional view of a part of the luminaire;

[0037] Figure 6 Shows a part of the luminaire in a top-down sectional view;

[0038] Figure 7 Shows a lens plate and another luminaire; and

[0039] Figure 8 Shows an isometric illumination diagram of a luminaire without a total internal reflection part and a luminaire with a total internal reflection part. Detailed Description

[0040] The present invention will be described with reference to the accompanying drawings.

[0041] It should be understood that although the detailed description and specific examples illustrate exemplary embodiments of the device, system, and method, they are for illustrative purposes only and are not intended to limit the scope of the present invention. These and other features, aspects, and advantages of the device, system, and method of the present invention will become more readily apparent from the following description, appended claims, and drawings. It should be understood that the drawings are only schematic and not drawn to scale. It should also be understood that the same reference numerals are used throughout all the drawings to indicate the same or similar components.

[0042] The present invention provides a lens unit for guiding light generated by a light source of a luminaire, the lens unit including a refraction part and a total internal reflection part, the total internal reflection part being arranged in an L shape.

[0043] The proposed method is based on the recognition that by using an L shape, the total internal reflection part can be used to guide light away from the corner. Therefore, the proposed lens unit is particularly suitable for illuminating the environment from the corner of the environment. The proposed method improves the uniformity and illumination range of the luminaire using the lens unit.

[0044] The embodiment can be used in any suitable lighting environment that requires illuminating a certain area / region from a corner.

[0045] Figure 1 Shows the lens unit 100 for the proposed embodiment. The light source used with the lens unit is located in or above the xy plane. Specifically, the light source can be mounted to be located on the xy plane, which will be described later.

[0046] The lens unit 100 is formed by a refractive portion 110 and a total internal reflection portion 120 (also referred to as the TIR portion). The lens unit 100 is preferably formed of one or more optically non-absorbing materials, i.e., any suitable material having an absorption rate of light incident thereon of less than 5%, e.g., less than 1%. Suitable examples include appropriately configured / designed plastics such as polycarbonate or PMMA, or glass.

[0047] In some examples, the lens unit is formed of a single homogeneous block of material, e.g., a single block of plastic or glass.

[0048] The total internal reflection portion 120 is formed by a first sub-portion 121 and a second sub-portion 122. These two sub-portions 121 and 122 are positioned to form an L-shape when viewed in the z-direction perpendicular to the plane xy. Conceptually, this means that assuming the plane xy is a horizontal plane, the total internal reflection portion 120 is L-shaped, or L-shaped when viewed vertically downward from above.

[0049] The L-shape means that the first and second sub-portions can be substantially perpendicular to each other, e.g., forming an angle of 90° ± 5°, e.g., 90° ± 2°. In some preferred examples, the first and second sub-portions are at right angles to each other (e.g., 90° ± 0.5°). In other words, the first and second sub-portions can be effectively positioned as two sides of a square / rectangle.

[0050] However, this is not necessary. In some examples, the angle between the first and second sub-portions can be larger, e.g., 90° ± 45°, e.g., 90° ± 30°, e.g., 90° ± 15°. This can achieve a controllable design for irradiated areas of different shapes / sizes.

[0051] The total internal reflection portion 120 is arranged around the refractive portion (e.g., only on both of its sides). Thus, the refractive portion 110 is positioned such that it is effectively bounded by the two sub-portions of the total internal reflection portion. Specifically, the total internal reflection portion 120 can bound both sides of the volume in which the refractive portion 110 is positioned or be located on the boundaries on both sides of the volume in which the refractive portion 110 is positioned.

[0052] The refractive portion 110 can be surrounded by the total internal reflection portion 120 only on both sides. More generally, the refractive portion 110 can be surrounded by any element of the lens unit (including the total internal reflection portion 120) only on both sides.

[0053] Accordingly, at least two sides of the total internal reflection portion can be exposed. In other words, the lens unit can allow light emitted from at least two sides of the refraction portion to escape the lens unit without intersecting the total internal reflection portion 120. In the illustrated example, the first and second sub-portions meet at the corner location 125. Accordingly, the first and second sub-portions are effectively adjacent to each other.

[0054] In use, the corner location 125 can be positioned by a luminaire including the lens unit at the corner of the area to be illuminated, where the sub-portions of the total internal reflection portion are positioned along a boundary extending into the corner of the area to be illuminated.

[0055] The purpose of the proposed lens unit 100 is to increase the amount of light emitted from the lens unit in a direction away from the total internal reflection portion (i.e., in use: away from the corner where the lens unit is positioned).

[0056] Specifically, if a light source is placed such that it is surrounded (and thus partially enclosed) by the L-shaped structure of the total internal reflection portion on both sides, the proposed lens unit will increase the amount of light emitted in a direction parallel to the direction in which the light source emits and away from the total internal reflection portion. This provides a more efficient mechanism for illuminating an environment from a corner of the environment (e.g., if the total internal reflection portion is positioned facing the corner).

[0057] The total internal reflection portion 120 also defines a first surface 131 and a second surface 132. The first surface 131 faces the refraction portion, and the second surface faces away from the refraction portion. Accordingly, the first surface is closer to the refraction portion 110 than the second surface.

[0058] In use, the first surface 131 will face the area / environment to be illuminated, while the second surface 132 will face away from the area / environment to be illuminated (e.g., towards the corner of the area to be illuminated). Specifically, when the light source is positioned such that it is enclosed by the total internal reflection portion on both sides, the lens unit provides an enhanced light intensity along a direction parallel to and away from the first surface 131 and a reduced light intensity along a direction parallel to and towards the first surface 131.

[0059] Figure 2 A portion of a luminaire 10 including the lens unit 100 is shown.

[0060] The luminaire also includes a light source 250. The light source includes any suitable light-emitting element for generating and emitting light, such as an LED or an LED array, e.g., a surface-mounted device LED arrangement or a chip-on-board LED arrangement.

[0061] The light source 250 is positioned below the refractive portion 110 and within the region or volume defined by the total internal reflection portion 120. Specifically, the total internal reflection portion 120 may define the two sides of the volume within which the light source is positioned or the boundaries on the two sides of the volume within which the light source is positioned.

[0062] The light source 250 is also positioned below the total internal reflection portion such that the total internal reflection portion does not intersect the plane in which the light source 250 is located. In other words, the total internal reflection portion is separated from or at a distance from the plane in which the light source 250 is located.

[0063] More specifically, the light source 250 is located within the light source cavity 162. The plane in which the light source cavity 162 is located is at a distance from the total internal reflection portion and the refractive portion. In other words, the total internal reflection portion does not intersect the plane in which the light source is located. Accordingly, the light source cavity 162 is located below the total internal reflection portion (and the refractive portion 110).

[0064] The luminaire 10 further includes a base 260 (e.g., a PCB). The base 260 is configured to support the lens unit 100 and the light source 250. More specifically, the base may be located in the xy plane (i.e., the plane on which the light source 250 is positioned). The z direction is perpendicular to the base 260.

[0065] As Figure 2 shown, the lens unit 100 may include a support portion 150 that supports the refractive portion 110 and the total internal reflection portion 120. The support portion may be, for example, generally planar or have a rectangular cross-section. The support portion may define an upper surface within the upper surface plane. The refractive portion and the total internal reflection portion may be effectively located on the upper surface plane. More specifically, the total internal reflection portion may abut the support portion at the upper surface plane.

[0066] As Figure 2 shown, the lens unit 100 includes a groove, cavity, gap or space 160 within which the light source 250 is positioned. This provides a more compact luminaire and reduces the coupling between the light source 250 and the lens unit 100. The light source cavity 162 may form part or a portion of the cavity 160 within which the light source 250 is positioned.

[0067] The light source cavity 162 may be formed within the support portion 150, and the refractive portion 110 and the total internal reflection portion 120 are positioned on the support portion 150.

[0068] The cavity 160 is at least partially defined by a light incident surface 165, which is the surface of the lens unit 100 that receives the light emitted by the light source 250. The light received at the light incident surface is transmitted into the refractive portion 110 or the total internal reflection portion 120.

[0069] Figure 3 A cross-sectional view of a part of the luminaire 10 including the lens unit 100 is provided, which better shows the cavity 160.

[0070] As Figure 3 shown, the cavity 160 can conceptually be divided into an (optional) optical cavity 161 and a light source cavity 162. The optical cavity 161 is configured to receive light emitted by the light source 250. The size and / or shape of the light source cavity 162 is designed to accommodate or hold the light source 250. When viewed along the z-direction (perpendicular to the x-y plane in which the light source is positioned), the cross-sectional shape of the light source cavity is larger than the cross-sectional shape of the optical cavity. This allows for increased flexibility in light source positioning and allows for the placement of power supply, driving, and / or control elements of the light source within the light source cavity 162 without affecting the optical performance of the lens unit.

[0071] The height h of the light source cavity 162 LSC is preferably greater than the height h of the light source 250 LS . The height h of the light source cavity 162 LSC can also alternatively be referred to as a clearance gap. This approach helps to avoid or reduce any mechanical interference between the light source 250 and the lens unit 100, especially in cases where the height of the light source is affected by manufacturing tolerances.

[0072] The height can be defined as the dimension along the direction perpendicular to the plane x-y on which the light source is positioned, i.e., the dimension along the z-direction.

[0073] In a specific example, the height h of the light source cavity 162 LSC is not less than 5 mm, for example not less than 7 mm. This provides a good tolerance for mounting different types of light sources 250 without causing mechanical interference between the light source and the lens unit.

[0074] The specific shape of the light source cavity depends on the size and shape of the light source. The shape of the light source cavity can be, for example, circular, square, or any other regular / irregular shape.

[0075] As previously mentioned, the light source 250 is positioned in the plane x-y. The refractive part and the total internal reflection part are at a certain distance from this plane, for example, so as not to intersect this first plane. Thus, the plane in which the light source or the light source cavity 162 is located is at a certain distance from the refractive part and the total internal reflection part, for example, not intersecting any part.

[0076] In other words, the light source cavity 162 is located below or beneath the refractive part 110 and the total internal reflection part 125. In other words, the light source cavity 162 is located in the first plane, and the refractive part and the total internal reflection part are located in a plane different from the first plane.

[0077] The total internal reflection portion 120 is disposed around (on both sides of) the refraction portion. Thus, the refraction portion 110 is positioned such that it is effectively defined by two sub-portions of the refraction portion located within the region or volume surrounded by the total internal reflection portion. Specifically, the total internal reflection portion 120 may define the boundaries on both sides of the volume within which the refraction portion 110 is positioned or be located on the boundaries on both sides of the volume within which the refraction portion 110 is positioned.

[0078] In some variations of the proposed method, the optical cavity 161 may be omitted.

[0079] Figure 4 A cross-sectional view of the luminaire 10 including the lens unit 100 is provided.

[0080] Figure 4 Helps to illustrate the positional relationship between the light source cavity 162, the refraction portion 110, and the total internal reflection portions 121, 122 of the lens unit.

[0081] More specifically, Figure 4 It is shown that the plane x - y on which the light source (and the light source cavity 162) is positioned is at a certain distance from the total internal reflection portion 120 and the refraction portion 110. In this way, the refraction portion and the total internal reflection portion can be closer to the light output surface of the lens unit than the light source cavity 162 (and thus than the light source 250).

[0082] Therefore, if the light source or the light source cavity 162 is considered to be located on the first plane x - y, the total internal reflection portion will not intersect the first plane x - y.

[0083] Figure 4 The paths taken by different light rays 410, 420, 430 generated by the light source 250 are also shown in dashed / dotted lines.

[0084] The total internal reflection portion 120 of the lens unit is configured to reflect the light received from the light source 250 using total internal reflection (TIR).

[0085] The principle of total internal reflection has been well - established in the art and will not be elaborated herein for the sake of brevity. Generally, total internal reflection utilizes the interaction of light rays with the boundary between different materials having different refractive indices (e.g., air and the material of the total internal reflection portion) to achieve the reflection of light.

[0086] The TIR effect of the total internal reflection portion 120 may be best illustrated by the path of a first light ray 410 that is emitted by a light source 250 and enters the total internal reflection portion 120. The first light ray 410 is reflected (by total internal reflection) from a second surface 132 of the total internal reflection portion 120 and then transmitted through a first surface 131. In this way, the first light ray is reflected by the total internal reflection portion 120 by total internal reflection.

[0087] Obviously, the proposed method increases the amount of light emitted in a direction parallel to the direction from which the light source 250 emits and away from the total internal reflection portion (i.e., away from the first surface 131 of the total internal reflection portion 120). More specifically, compared to the number of light rays output from the second surface 132 (if there is no such TIR surface 132, thus away from the desired illumination area), the proposed method increases the number of light rays output from the first surface 131 of the total internal reflection portion (thus towards the desired area for illumination).

[0088] The refraction portion 110 is configured to refract light received from the light source 250.

[0089] The illustrated refraction portion 110 is shaped like a dome with its vertex 111 or top off - center. Specifically, compared to a dome with a central vertex or top, the vertex or top of the dome is positioned farther away from the total internal reflection portion 120. This design helps to direct the light received by the refraction portion 110 away from the total internal reflection portion, thus improving the light intensity and distribution in a direction away from the first surface 131 of the total internal reflection portion 120.

[0090] The proposed system also reduces the average value of the angle between the light rays emitted from the lens unit and the x - y plane in which the light source is located. This method increases the amount of light reaching positions in the external environment that are far from the lens unit (i.e., before reaching the floor or ground).

[0091] Figure 4 Also shown is the path taken by a second light ray 420 generated by the light source 250 in a direction away from the total internal reflection portion 120. The second light ray 420 is received by the refraction portion 110 and is directed further away from the total internal reflection portion 120.

[0092] Figure 4 Also shown is the path taken by a third light ray 430 that is emitted into the refraction portion 110. The third light ray 430 is refracted towards the total internal reflection portion 120 and undergoes total internal reflection at the second surface 132 of the total internal reflection portion (i.e., is redirected away through the first surface 131 of the total internal reflection portion).

[0093] The refractive portion 110 and the total internal reflection portion 120 are designed such that light refracted toward the total internal reflection portion (through the refractive portion 110) undergoes total internal reflection through the total internal reflection portion to reduce the amount of light transmitted through the total internal reflection portion - that is, to increase the amount of light guided out of the first surface 131 of the total internal reflection portion (and thus increase the direction away from the first surface 131 of the total internal reflection portion 120).

[0094] In this way, in use, the lens unit reduces the amount of light output by it in the direction along the outside of the lens unit and away from the second surface (e.g., toward the lamp or the corner in which the lens unit is positioned). As described above, in use, the lens unit is positioned such that the second surface faces the corner of the area to be illuminated in which the lamp is positioned.

[0095] In some examples, as shown, wherein (on average) the heights h1, h2 of the first sub - portion 121 and the second sub - portion 122 each decrease as the distance from the corner position 125 increases. This approach provides a smoother transition between the light emitted in the direction away from the first surface 131 of the total internal reflection portion and the other light emitted by the lamp 10.

[0096] As Figure 4 shown, each sub - portion can start from a first height h1 and then decrease to a second smaller height h2 that is farther from the corner position 125. For example, the height can follow a curve - such that the height initially increases and then decreases to the second height.

[0097] As Figure 4 shown, the second surface 132 of the total internal reflection portion is inclined with respect to the xy - plane in which the light source is positioned. Specifically, the second surface 132 can be considered to form an angle or be inclined toward the refractive portion 110, that is, perpendicular to it. This approach reduces the effective angular size of the light reflected by the second surface 132 by TIR with respect to the x - y plane. This approach increases the amount of light reaching positions in the external environment away from the lens unit (i.e., before reaching the floor or ground). Tilting the second surface in this way thus increases the illumination range of the lamp including the lens unit 100.

[0098] More specifically, the second surface 132 includes a proximal end 132a and a distal end 132b. The proximal end is positioned closer to the light source cavity 162 than the distal end 132b, that is, closer to the plane x - y. In a cross - section passing through the axis LS, the distance D1 between the proximal end 132a and the axis LS is greater than the distance D2 between the distal end 132b and the axis LS. In this way, the second surface effectively inclines toward the refractive portion 110.

[0099] The proximal end 132a of the second surface 132 can be in contact with the support portion 150 of the lens unit 100. Specifically, the second surface 132 can terminate at the support portion 150 of the lens unit, where there is a significant angle (e.g., >20°) between the second surface 132 and the upper surface 151 of the support portion 150. The upper surface 151 of the support portion is also at a certain distance from the x-y plane in which the light source is positioned. In other words, there is a vertex at the junction of the second surface 132 and the support portion 150 (at the proximal end 132a of the second surface 130), where the angle between the second surface and the support portion is greater than 20°, e.g., greater than 60°.

[0100] In this way, the total internal reflection portion 120 appears to extend outward from the support portion 150 of the lens unit 100.

[0101] In some examples, the second surface 132 of the total internal reflection portion can be curved. The center of curvature of the second surface (if it is curved) is positioned on the same side as the second surface and the light source or the refraction unit.

[0102] As Figure 4 shown, the first surface 131 of the total internal reflection portion can also be inclined with respect to the plane in which the lens unit is located. Specifically, the second surface can form an angle or be inclined with respect to the refraction portion 110. This can reduce the angle between the light rays reflected from the second surface 132 and the light rays reaching the first surface 131, thereby increasing the number of light rays escaping from the total internal reflection portion in a direction away from the first surface (i.e., reducing the number of light rays reflected again by the first surface 131 through TIR).

[0103] Figure 5 Another cross-sectional view of part of the lamp 10 is provided, more clearly showing the elements of the lens unit 100. Figure 5 A view of the proposed shape of the refraction portion is also provided, i.e., a dome with an eccentric vertex or top.

[0104] Figure 6 A top-down sectional view of a part of the lamp 10 is provided. Specifically, the refraction portion of the lens unit 100 is omitted in this figure.

[0105] Figure 6 This helps to illustrate the positional relationship between the lens unit 100 and the light source 250 according to one embodiment. Specifically, the lens unit 100 and the light source 250 can be positioned such that the light source is surrounded by the volume (e.g., on both sides) defined by the total internal reflection portion of the lens unit. More specifically, the light source can be partially surrounded by the volume defined by the L-shape formed by the first sub-portion and the second sub-portion of the total internal reflection portion of the lens.

[0106] Figure 6 Also shown is how the light source 250 is formed by the LED package 251 and the light emitting surface 255 on top of the LED package 251.

[0107] Figure 7 Shown is a luminaire 70, which includes a lens plate 700 that includes an array of the aforementioned lens units 100 (i.e., a plurality of lens units 100). Each lens unit is mounted on the same lens plate base 750.

[0108] The illustrated lens plate 700 is made of a uniform block of material. The array of lens units is arranged in a regular grid. However, those skilled in the art can understand other arrangements, for example, a circular arrangement or a pseudo-random arrangement. The regular grid can improve the uniformity of the light output by the luminaire 70.

[0109] The array of lens units preferably includes no less than five lens units, for example, no less than nine lens units. In the illustrated example, the lens unit array includes nine lens units, which are arranged in a regular 3x3 grid.

[0110] It is noted that the luminaire 70 includes a light source 250 corresponding to each lens unit of the lens plate, which is configured to generate light and is positioned to emit the light into the lens unit. Thus, each lens unit 100 of the lens plate 700 has a corresponding light source. The suitable positional relationship between the lens unit and its corresponding light source has been described above.

[0111] Of course, the luminaire may include a mounting plate 260 for mounting the lens plate 70 and the light source 250 thereon.

[0112] Figure 8 An isophote diagram 810 for a luminaire having a first lens plate is shown, which lens plate includes lens units that do not have a total internal reflection portion.

[0113] Figure 8 An isophote diagram 820 for a luminaire having a second lens plate is also shown, which lens plate includes lens units that have a total internal reflection portion. The lens units of the first lens plate and the lens units of the second lens plate are identical in all other respects.

[0114] In both plots 810, 820, the luminaire has been positioned at the origin, i.e., the point (0,0). The first sub-section of each lens unit is parallel to the y-axis, and the second sub-section is parallel to the x-axis. The first surface of the total internal reflection unit faces the first quadrant of the plot (i.e., the upper right corner).

[0115] Figure 8Clearly shows how the range and uniformity of the light output by a luminaire having a second lens plate is improved compared to a luminaire having a first lens plate. Thus, the (multiple) total internal reflection portions provide better uniformity and illumination ability for the luminaire.

[0116]

[0117] Table 1

[0118] Table 1 shows the results of an experimental measurement of the improvement brought about by using a lens unit having total internal reflection portions. The light output rate represents the percentage increase in the light output of the luminaire in the desired direction (i.e., away from the corner).

[0119] The "baseline" type means that the lens unit includes a refractive portion (but no TIR portion), where the refractive portion is shaped as a dome with the vertex or top centered (i.e., a non-skewed dome). The "no total internal reflection portion" type means that the lens unit includes a refractive portion 110 (but no TIR portion 120), where the refractive portion is shaped as a dome with the vertex or top not centered, for example, having the shape shown in the figure. The "with TIR portion" type means that the lens unit has the same refractive portion 110 as the "no TIR portion" type but includes a total internal reflection portion 120.

[0120] From Table 1, it can be seen that there is a direct increase in the light output rate due to the use of the TIR portion 120.

[0121] Those skilled in the art, in practicing the present invention, can understand and implement various variations of the disclosed embodiments by studying the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0122] Just because certain measures are recited in mutually different dependent claims does not mean that the combination of these measures cannot be utilized to its full extent.

[0123] If the word "suitable for" is used in the claims or the specification, it should be noted that the meaning of the word "suitable" is the same as the meaning of "configured to". If the word "means" is used in the claims or the specification, it should be noted that the meaning of the word "means" is the same as the meaning of "system", and vice versa.

[0124] Any reference signs in the claims shall not be construed as limiting the scope.

Claims

1. A lens unit (100) for a luminaire, comprising a light source having an axis (LS) perpendicular to a plane (xy), the light source being positioned on the plane, the lens unit comprising: a light source cavity (162) for receiving light from the light source, the light source being locatable in the light source cavity; a refraction portion (110), spaced apart from the plane (xy), for refracting light received from the light source; and a total internal reflection portion (120), spaced apart from the plane (xy), wherein the total internal reflection portion (120) comprises a first sub-portion (121) and a second sub-portion (122), the first sub-portion and the second sub-portion being angled relative to each other such that an L-shape is formed when viewed in a direction (z) perpendicular to the plane (xy); wherein the first sub-portion (121) and the second sub-portion (122) of the total internal reflection portion (120) each comprise a first surface (131) facing the refraction portion (110) and a second surface (132) facing away from the refraction portion (110), wherein the second surface (132) is inclined relative to the plane (xy) to reflect light received from the light source by total internal reflection; wherein the second surface (132) comprises a proximal end (132a) and a distal end (132b), the proximal end (132a) being closer to the light source cavity (162) than the distal end (132b), and wherein in a cross-section passing through the axis (LS), the distance (D1) between the proximal end (132a) and the axis (LS) is greater than the distance (D2) between the distal end (132b) and the axis (LS).

2. The lens unit (100) according to claim 1, wherein the first sub-portion (121) and the second sub-portion (122) are substantially perpendicular to each other.

3. The lens unit (100) according to claim 2, wherein the first sub-portion (121) and the second sub-portion (122) are at a right angle to each other.

4. The lens unit (100) according to any one of claims 1 to 3, wherein the first sub-portion (121) meets the second sub-portion (122) at a corner position (125).

5. The lens unit (100) according to claim 4, wherein, On average, the height (h1, h2) of each of the first sub-portion (121) and the second sub-portion (122) decreases as the distance from the corner position (125) increases.

6. The lens unit (100) according to any one of claims 1 to 5, wherein the lens unit is formed from a homogeneous block of material.

7. A luminaire (10), comprising: the lens unit (100) according to any one of claims 1 to 6; and a light source (250) configured to generate light, wherein the light source is positioned to emit light into the lens unit.

8. The luminaire (10) according to claim 7, wherein the height (h LSC ) of the light source cavity (162) is greater than the height (h LS ) of the light source (250).

9. The luminaire (10) according to claim 7 or 8, wherein the light source is positioned to be partially surrounded by a volume defined by an L-shape formed by the first sub-part and the second sub-part of the total internal reflection part of the lens unit.

10. A lens plate (600) comprising an array of lens units (100) according to any one of claims 1 to 6.

11. The lens plate (600) according to claim 10, wherein the lens plate is formed from a homogeneous block of material.

12. A luminaire (60) comprising: a lens plate (600) according to any one of claims 10 to 11; and for each lens unit (100) of the lens plate, a corresponding light source (250) configured to generate light and positioned in a light source cavity of the lens unit and positioned to emit light into the lens unit.

13. The luminaire according to claim 12, wherein, For each lens unit of the lens plate, the corresponding light source is located within a volume partially surrounded by an L-shape formed by the first sub-part and the second sub-part of the total internal reflection part of the lens unit.

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