Table lamp with light guide plate device

Abstract

A table lamp has a lighting device with a light guide plate having an asymmetric light extraction feature. The asymmetric light extraction feature protrudes or extends toward the light transmission window / light incidence window / surface of the light guide plate and is angled relative to the light transmission window.

Description

TECHNICAL FIELD

[0001] The present utility model relates to the field of lighting, and in particular to the field of lighting for desks or tables. BACKGROUND

[0002] Despite the increasing use of light emitting diodes (LEDs), which increases the flexibility of lighting design, it also brings pixelation. This is often seen as an undesirable or annoying side effect and gives the user discomfort. Light guide plates are increasingly used to help distribute the light emitted by the light emitting diodes to effectively soften and / or de-pixelate the emitted light.

[0003] One use case scenario for lamps is desk lamps. One challenge with desk lamps is that they have to be compact, which only provides a limited space for the light emitting elements. Therefore, it is difficult to provide an optical design that has both a wide and uniform illumination for a desk.

[0004] Therefore, it is desirable to provide a solution for a desk lamp that at least addresses some of these problems or difficulties. SUMMARY

[0005] According to an example of an aspect of the present utility model, there is provided a light guide plate arrangement for a desk lamp.

[0006] The light guide plate arrangement comprises a light guide plate for transporting light, the light guide plate comprising: a light transport window configured to couple light transported by a light source into the light guide plate; and a light exit window configured to couple light out of the light guide plate, the light exit window being at an angle between 80° and 100° relative to the light transport window.

[0007] The light guide plate arrangement further comprises a first reflective surface positioned on the light guide plate and opposite the light transport window for reflecting light incident on the first reflective surface, wherein the light exit window is positioned between the light transport window and the first reflective surface; a plurality of asymmetric light extraction features for directing light in the light guide plate towards the light exit window, wherein for each asymmetric light extraction feature: in a first plane, a curvature of a first side of the asymmetric light extraction feature is greater than a curvature of a second side of the asymmetric light extraction feature, the first plane being a plane parallel to the light exit window, wherein a longitudinal axis of the asymmetric light extraction feature is at a non-zero and non-perpendicular angle relative to the light transport window; and in the first plane, the curvature of the first side of the asymmetric light extraction feature is less than the curvature of the second side of the asymmetric light extraction feature, the first plane being a plane parallel to the light exit window, wherein: the first side is on one side of a second plane, the second plane being a plane perpendicular to the light exit window and passing through the longitudinal axis of the asymmetric light extraction feature; the second side of the asymmetric light extraction feature is on the other side of the second plane; and the first side is closer to the light transport window than the second side.

[0008] Thus, the present disclosure proposes a method in which the asymmetric light extraction features extend toward the light transmission window (and therefore toward the light source) and away from the first reflective surface. This increases the amount of light guided by the light guide plate in a forward direction relative to the direction in which light is transmitted from the light source into the light guide plate. This helps improve the uniformity and spread of the light distributed by the light guide plate.

[0009] The present disclosure also proposes tilting each asymmetric light extraction feature relative to the light transmission window of the light guide plate and the light source. This approach increases the lateral spread of the desk lamp.

[0010] Each asymmetric light extraction feature may be configured such that in a second plane, which is a plane perpendicular to the light exit window and perpendicular to the light transmission window, the curvature of the first side of the asymmetric light extraction feature is smaller than the curvature of the second side of the asymmetric light extraction feature.

[0011] Therefore, in the second plane, the average gradient of the first side may be smaller than the average gradient of the second side.

[0012] This approach also enhances the effect of increasing the amount of light guided by the light guide plate in a forward direction relative to the direction in which light is transmitted from the light source into the light guide plate.

[0013] Preferably, for each asymmetric light extraction feature, the longitudinal axis is angled between 10° and 50° relative to the light transmission window. This angle changes or affects the direction of lateral light. In some embodiments, the plurality of asymmetric light extraction features includes at least 20 asymmetric light extraction features. The greater the number of features, the greater the effect provided by the plurality of asymmetric light extraction features. The at least 20 asymmetric light extraction features preferably include at least 50 asymmetric light extraction features, such as at least 100 asymmetric light extraction features.

[0014] A plurality of asymmetric light extraction features may be arranged in a pattern of two or more interwoven or overlapping columns.This approach increases the density of the asymmetric light extraction features and, therefore, increases the effect provided by the asymmetric light extraction features.

[0015] Each of the plurality of asymmetric light extraction features may be formed by a hole or indentation in the light guide plate. This provides a mechanism for providing asymmetric light extraction features that is easily manufactured, for example by modifying or etching an existing mold for a light guide plate.

[0016] As an alternative example, each of the plurality of asymmetric light extraction features may be formed of a different material than the rest of the light guide plate, ie, a material having a different refractive index.

[0017] In some examples, each asymmetric light extraction feature of the plurality of asymmetric light extraction features is formed at a surface of the light guide panel opposite the light exit window.

[0018] Preferably, each asymmetric light extraction feature of the plurality of asymmetric light extraction features has a surface roughness Ra between 0.1 pm and 20 pm. This increases the amount of light scattered by the asymmetric light extraction features, and thus increases the uniformity of the light distributed by the light guide panel.

[0019] The light exit window can be at an angle between 85° and 95° with respect to the light transmission window. In particular, the light exit window can be perpendicular to the light transmission window.

[0020] It is also proposed an illumination device comprising: any light guide panel device described herein; and a light source configured to transmit light to the light transmission window. An optical axis of the transmitted light, e.g. a central axis, can be perpendicular to the light transmission window, e.g. orthogonal to the light transmission window.

[0021] It is also proposed a desk lamp comprising: a first illumination device, which is an illumination device described herein; and a support for mounting the first illumination device.

[0022] The desk lamp can further comprise a second illumination device, which is another illumination device described herein. The support can be correspondingly configured to mount the second illumination device.

[0023] Preferably, the plurality of asymmetric light extraction features of the first illumination device are mirror versions of the plurality of asymmetric light extraction features of the second illumination device. This means that the lateral spread of light caused by the angled asymmetric light extraction features of the first and second illumination devices will be in opposite directions, increasing the spread of light provided by the desk lamp, and improving the uniformity of the light provided by the desk lamp (as the lateral spread will not overlap or have a reduced amount of overlap with each other).

[0024] When the support is positioned on a planar surface, the support can be configured to allow the first and second illumination devices, if present, to be positioned at a distance greater than 30 cm from the planar surface.

[0025] These and other aspects of the present application will become apparent from and elucidated with reference to the embodiments described hereinafter (one or more of). BRIEF DESCRIPTION OF DRAWINGS

[0026] For a better understanding of the present application, and to show more clearly how it can be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which:

[0027] Figure 1An exploded view of the lighting device using 3D perspective is provided;

[0028] Figure 2 An assembled view of the lighting device is provided;

[0029] Figure 3 A cross-sectional view of the lighting device in the X-Y plane is provided;

[0030] Figure 4 Asymmetric light extraction features in the X’-Y’ plane are illustrated;

[0031] Figure 5 A cross-sectional view of the lighting device in the Y-Z plane is provided;

[0032] Figure 6 Asymmetric light extraction features in the Y’-Z plane are illustrated;

[0033] Figure 7 Propagation of a first light ray through the lighting device is illustrated;

[0034] Figure 8 Propagation of a second light ray through the lighting device is illustrated;

[0035] Figure 9 A pattern of multiple asymmetric light extraction features is illustrated;

[0036] Figure 10 A desk lamp is illustrated;

[0037] Figure 11 Mirror symmetry of asymmetric light extraction features for two different lighting devices is illustrated; and

[0038] Figure 12 An exploded view of the lighting device is provided. DETAILED DESCRIPTION

[0039] The present utility model will be described with reference to the accompanying drawings.

[0040] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of apparatuses, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the present utility model. These and other features, aspects, and advantages of the apparatuses, systems and methods of the present utility model will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the drawings are only schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings for like or similar items.

[0041] The utility model provides a lighting device with a light guide plate, which has asymmetric light extraction features. The asymmetric light extraction features project out of or extend from the light transport window / light entrance window / surface of the light guide plate and are angled relative to the light transport window.

[0042] The embodiments are based on the recognition that asymmetric light extraction features, i.e. light extraction features having an off-center optical axis, can help control the light emitted from the light guide plate of a desk lamp. In particular, the uniformity and spread of the light emitted by the light guide plate can be increased.

[0043] The proposed method can be used in any environment where a desk lamp is used, such as an office, school and / or home desktop setting. Other suitable use case scenarios will be apparent to the skilled person.

[0044] Figure 1 And Figure 2 A 3D projection of the lighting device 50 is provided. Figure 1 An exploded view is provided, and Figure 2 An assembled view is provided.

[0045] The lighting device 50 comprises a light guide plate device 100 and a light source 190, which light guide plate device itself is an embodiment of the utility model.

[0046] Figure 1 Three axes of the lighting device 50 and / or the light guide plate device 100 are identified. These axes include an X-axis spanning the width of the light guide plate device, a Y-axis spanning the length of the light guide plate device and a Z-axis spanning the height or depth of the light guide plate device.

[0047] The light guide plate configuration 100 comprises a light guide plate 105, a first reflective surface 120, a plurality of asymmetric light extraction features 150, (optional) a second reflective surface 170 and (optional) side reflective surfaces 181, 182.

[0048] For clarity of illustration, Figure 2 The illustration of the second reflective surface 170 and one of the side reflective surfaces 181 is omitted in the middle.

[0049] The light guide plate 105 is configured for transporting light, e.g. formed of a transparent and / or translucent material. The light guide plate comprises a transport window 110 and a light exit window 130. The light transport window 110 is configured to couple light transported by a light source (e.g. positioned to emit light towards the light transport window 110) into the light guide plate. The light exit window 130 is configured to couple light out of the light exit window 130. Light is generally transported into the light guide plate 105 along the Y-axis.

[0050] The light exit window 130 is angled between 80° and 100° relative to the light transport window 110. In this way, the light exit window can be substantially perpendicular or perpendicular to the light transport window. For example, the light exit window can be angled between 85° and 95° relative to the light transport window.

[0051] In Figure 1 and Figure 2 the light exit window 130 is located on the underside of the illustrated illumination device.

[0052] Accordingly, the light exit window is located in the X-Y plane. The light transport window 110 is located in the X-Z plane, and is therefore perpendicular to the light exit window 130. The directions of the axes X, Y, Z can be defined by the planes in which the light transport window and the light exit window are located. In particular, the light transport window is located in the X-Z plane, and the light exit window is located in the X-Y plane.

[0053] In this way, the illumination device 50 has a side-lit design, as light (via the light exit window 130) is redirected by the light guide panel from the light transport window 110 to exit at a non-zero angle to the light transport window 110.

[0054] Methods for forming light transport windows (also referred to as light entrance windows) and / or light exit windows are well known in the art, and can include suitably texturing or shaping the window(s) to facilitate light coupling into / out of the light guide panel.

[0055] The first reflective surface 120 is located on the light guide panel 105, opposite the light transport window 110. The first reflective surface is configured to reflect light incident thereon. Methods for forming the first reflective surface 120 include depositing a reflective material on a surface of the light guide panel 105 and / or coupling a reflective layer / slice of material to a surface of the light guide panel 105.

[0056] The light exit window 130 is located between the light transport window 110 and the first reflective surface 120. In this way, the light exit window is also at a non-zero angle relative to the first reflective surface 120. For example, the light exit window 130 can be angled between 80° and 100° relative to the first reflective surface 120, for example substantially perpendicular to the first reflective surface 120.

[0057] The plurality of asymmetric light extraction features are configured to aid in directing light towards the light exit window.

[0058] Each asymmetric light extraction feature can be formed as a feature of the light guide panel 105 or within the light guide panel 105.

[0059] As shown, each of the plurality of asymmetric light extraction features can be formed by a hole or indentation in the light guide plate. This approach provides a light guide plate arrangement that is easy to manufacture, e.g., because the light extraction features can be integrated into the light guide plate by a simple modification of the mold or model used for the light guide plate.

[0060] As another example, each asymmetric light extraction feature can be formed by a protrusion or bump of the light guide plate. This approach is also easy to manufacture, but reduces the compactness of the light guide plate.

[0061] In this way, each asymmetric light extraction feature can be formed at a surface 160 of the light guide plate 105 opposite the light exit window. Similarly, the light guide plate can comprise a plurality of 3D textures (that are holes and / or protrusions) on the surface opposite the light exit window.

[0062] As yet another example, each asymmetric light extraction feature can be formed by a material separate from the rest of the light guide plate. This can be achieved, for example, by forming a hole / indentation in the light guide plate and filling said hole with a material or by depositing a different material bump on the light guide plate.

[0063] As an example of asymmetric light extraction features that are not formed as features of the light guide plate or features within the light guide plate, each of the plurality of asymmetric light extraction features can be formed in a separate layer coupled to the light guide plate, e.g., on a surface opposite the light exit window.

[0064] The second reflective surface 170 and the side reflective surface(s) 181, 182, if present, are configured to reflect light back into the light guide plate, i.e., to contain light within the light guide plate. These reflective surfaces can be formed in the same or similar manner as the first reflective surface 120. The second reflective surface 170 is positioned opposite the light exit window, e.g., on the upper side 135 of the light guide plate. The side reflective surfaces 181, 182 are on the respective side surfaces 136, 137 of the light guide plate.

[0065] The light source 190 is configured to transmit light towards the light transmission window 110. The light source 190 can comprise one or more light emitting diodes for generating light that is transmitted towards the light transmission window 110. Although not shown, the light source 190 can be held in place by a printed circuit board.

[0066] One or both of the side reflective surfaces 181, 182 can be replaced with an additional light source, e.g., an additional set of one or more light emitting diodes. These light sources can be configured to emit light into a second light transmission window of the light guide plate. The second light transmission window can be perpendicular to the light transmission window. This approach will enhance the amount of light in the light guide plate.

[0067] Preferably, the plurality of asymmetric light extraction features comprises at least 20 asymmetric light extraction features, such as not less than 100 asymmetric light extraction features, such as not less than 500 asymmetric light extraction features.

[0068] Figure 3 A view of the light guide plate arrangement 100 in the X-Y plane, which can be labeled as "first plane", is provided. The size of the asymmetric light extraction features is exaggerated for clarity and explanation purposes.

[0069] Each asymmetric light extraction feature is configured such that, in the first plane X-Y, the curvature of the first side 151 of the asymmetric light extraction feature is smaller than the curvature of the second side 152 of the symmetric light extraction feature. The first side is closer to the light transport window 110 than the second side.

[0070] Hence, each asymmetric light extraction feature is convex towards the light transport window.

[0071] Hence, the average distance between the edge of the first side and the center of the asymmetric light extraction feature is larger than the average distance between the edge of the second side and the center of the asymmetric light extraction feature.

[0072] This approach means that the optical axis of the asymmetric light extraction feature is off-center, at least with respect to the first plane X-Y. The shape of each asymmetric light extraction feature is such that more light is distributed towards the opposite side of the light guide plate of the light transport window, i.e. the light distribution to locations further away from the light source is increased.

[0073] Figure 4 A magnified view of the asymmetric light extraction feature with respect to plane X'-Y' is provided, which plane X'-Y' lies in the same general plane as plane X-Y, but has an axial rotation (e.g. about the Z axis, which results in the entering / leaving of the sheet).

[0074] Figure 4 It is illustrated how the asymmetric light extraction feature is shaped as a sort of skewed oval, where one side 151 of the feature is more convex outwards than the other side 152 of the feature (in the X-Y plane).

[0075] Returning to Figure 3 Each asymmetric light extraction feature is further configured such that the longitudinal axis 159 of the asymmetric light extraction feature is at a non-zero and non-perpendicular angle with respect to the light transport window.

[0076] The longitudinal axis 159 is an axis that passes through the widest or longest part of the asymmetric light extraction feature in the first plane, i.e. along the length of the asymmetric light extraction feature. The term longitudinal axis is well used and established in the art to refer to such an axis of an object or element.

[0077] This method increases the lateral or side light distribution relative to the light transmission of the light source, for example towards a direction in the third quadrant of the X-Y plane.

[0078] Preferably, for each asymmetric light extraction feature, the longitudinal axis forms an angle between 10° and 50° with respect to the light transmission window.

[0079] The first side 151 of the asymmetric light extraction feature is located on one side of the longitudinal axis. The second side 152 of the asymmetric light extraction feature is located on the other side of the longitudinal axis.

[0080] In other words, the first side 151 of the asymmetric light extraction feature 150 is located on one side of a second plane, which is a plane perpendicular to the light exit window and passing through the longitudinal axis 159 of the asymmetric light extraction feature 150. The second side 152 of the asymmetric light extraction feature 150 is located on the other side of the second plane.

[0081] The average distance between the edges of the first side 151 and the longitudinal axis 159 is greater than the average distance between the edges of the second side 152 and the longitudinal axis 159.

[0082] Figure 5 A view of the light guide plate device 100 in the Y-Z plane is provided, which plane can be labeled as the “second plane”. For the sake of clarity and explanation, only one asymmetric light extraction feature 150 is illustrated, the size of which is enlarged.

[0083] The asymmetric light extraction feature 150 is configured such that, in a second plane perpendicular to the light exit window 130 and parallel to the light transmission window, the curvature of the first side 151 of the asymmetric light extraction feature 150 is smaller than the curvature of the second side 152 of the asymmetric light extraction feature 150.

[0084] In other words, in the Y-Z plane, the (average) steepness of the first side 151 is smaller than the (average) steepness of the second side 152. This is illustrated by the tangents G1, G2, which represent the average steepness of the two sides of the asymmetric light extraction feature.

[0085] In other words, the first side 151 can be (on average) less steep / sloped / sloped relative to the light exit window than the second side 152.

[0086] Figure 6 An enlarged view of the asymmetric light extraction feature with respect to the Y’-Z plane is provided, which Y’-Z plane lies in the same general plane as the plane Y-Z, but has an axial rotation about the Z axis.

[0087] Figure 6It is illustrated how the asymmetric light extraction feature 150 is shaped like a skewed half-circle, with one side 151 of the feature having a smaller curvature than the other side 152 of the feature.

[0088] As mentioned before, the first side 151 of the asymmetric light extraction feature 150 lies on one side of a second plane 510, which is a plane perpendicular to the light exit window and passing through the longitudinal axis 159 of the asymmetric light extraction feature 150. The second side 152 of the asymmetric light extraction feature 150 lies on the other side of the second plane.

[0089] This approach means that the optical axis of the asymmetric light extraction feature 150 is at least off-center with respect to the first plane Y’-Z’. The shape of the asymmetric light extraction feature 150 is such that more light is distributed towards the opposite side of the light guide plate of the light transport window, i.e. the light distribution to locations further away from the light source is increased.

[0090] Figure 7 And Figure 8 It is illustrated how the shape of the asymmetric light extraction feature 150, in particular the (average) steepness of the first side 151 being smaller than the (average) steepness of the second side 152 (in the Y-Z plane).

[0091] Figure 7 It is illustrated how a first light ray 710 is emitted from the light source 190 through the light transport window 110 at an angle θ1 with respect to the normal N1 of the light transport window.

[0092] The angle θ1 is such that when the first light ray 710 reaches the interface between the asymmetric light extraction feature and the rest of the light guide plate, the angle of incidence is larger than the critical angle of the interface. Therefore, the first light ray 710 is reflected towards the light exit window in the forward direction, i.e. in a direction having a positive component in the direction of the normal to the light transport window in the light guide plate.

[0093] Figure 8 It is illustrated how a second light ray 810 is emitted from the light source 190 through the light transport window 110 at an angle θ2 with respect to the normal of the light transport window. The angle θ2 is equal in absolute value to the angle θ1, but opposite in direction.

[0094] The angle θ2 is such that when the second light ray 810 exits the light exit window, it experiences total internal reflection. The second light ray 810 is then reflected by the first reflective surface 120. Due to the law of reflection, the angle θ2 between the normal N2 of the first reflective surface and the second light ray (when it is reflected by the first reflective surface) remains at the angle θ2.

[0095] In principle, if the first side 151 and the second side 152 of the asymmetric light extraction feature 150 had the same curvature, the second light ray 810 would also experience total internal reflection at the interface of the asymmetric light extraction feature and be reflected towards the light exit window 130. Thus, the second light ray 810 would be directed in a direction that is backwards with respect to the direction of the light transmitted into the light guide plate 105.

[0096] However, because the curvature of the second side 152 is larger than the curvature of the first side 151, the second light ray 810 is refracted into the asymmetric light extraction feature.

[0097] Thereby, this approach reduces the number of light rays that leave the light exit window in a backwards direction, i.e. in a direction that has a negative component in the normal N1 direction to the light transmission window in the light guide plate.

[0098] Figure 9 A pattern 900 of a plurality of asymmetric light extraction features 150 is illustrated. The pattern is formed by two or more interwoven or overlapping columns 911, 912, 913 of asymmetric light extraction features 150. This approach increases the number of asymmetric light extraction features 150 that can be provided per unit area, thereby increasing the effectiveness of the light redirection by the plurality of asymmetric light extraction features 150.

[0099] In any of the above embodiments, each of the plurality of asymmetric light extraction features 150 can have a surface roughness Ra between 0.1 pm and 20 pm, for example between 2 pm and 20 pm, for example between 5 pm and 20 pm. Ra is a well-known parameter for surface roughness and indicates the average or arithmetic mean of the profile height deviations from the mean line.

[0100] An increased surface roughness will increase the amount of light scattering or diffusion performed within the light guide plate arrangement 100, such that the light emitted from the light guide plate arrangement 100 will have a more uniform light distribution.

[0101] One suitable approach to make a surface with such a surface roughness is to etch or engrave the inner surface of the (injection) mold for the light guide plate and / or the asymmetric light extraction features. Then, during the molding process, the surface roughness will be transferred to the asymmetric light extraction features.

[0102] An alternative approach is to directly engrave or etch the asymmetric light extraction features themselves. This is less preferred, as the manufacturing process requires more resources.

[0103] Figure 10 A desk lamp 10 according to an embodiment is illustrated.

[0104] The desk lamp 10 comprises a first lighting device 50A as described before and a support 1010 for mounting the first lighting device. The desk lamp 10 further comprises (optional) a second lighting device 50B, which support 1010 is also configured to mount this second lighting device 50B.

[0105] Hence, the desk lamp 10 comprises a light system 1050 comprising the first lighting device 50A and the second lighting device 50B.

[0106] When the support 1010 is positioned on the planar surface 1090, the support can be configured to allow the first lighting device and the second lighting device (if present) to be positioned at a distance d from the planar surface 1090 which is larger than 30 cm. Of course, the size of the distance can be adjustable, e.g. the support 1010 can be height adjustable.

[0107] Preferably, the support 1010 is configured to prevent the distance d to be larger than 1 m when positioned on the planar surface 1090.

[0108] In this way, the desk lamp can be particularly configured for use with a desk.

[0109] Preferably, the plurality of asymmetric light extraction features of the second lighting device 50B is a mirrored version of the plurality of asymmetric light extraction features of the first lighting device 50A. This approach provides a more uniform light distribution over the surface on which the desk lamp is positioned.

[0110] The line of reflection symmetry can for instance be a line parallel to the normal of the light transport window of the light guide plate of the first lighting device or the second lighting device.

[0111] Figure 11 This concept is illustrated.

[0112] In particular, Figure 11 A first pattern / plurality of asymmetric light extraction features 1101 for the first lighting device is illustrated, as well as a second pattern / plurality of asymmetric light extraction features 1102 for the second lighting device. For clarity, also the respective light source 190 and light transport window 110 of each pattern / plurality of asymmetric light extraction features is illustrated.

[0113] Figure 11 It is shown how the first pattern / plurality 1101 of asymmetric light extraction features of the first lighting device can be a mirrored version of the second pattern / plurality 1102 of asymmetric light extraction features of the second lighting device. The line / plane of reflection symmetry (i.e. virtual mirror) 1150 is perpendicular to the light transport window 110, i.e. lies in the y-axis.

[0114] Hence, the first lighting device and the second lighting device are virtually mirror images of each other to distribute light forward to both sides.

[0115] Figure 12 An exploded view of the lighting device 50 is provided, illustrating other optional features of the lighting device.

[0116] The lighting device 50 comprises a light guide plate 105, a light source 190, an (optional) second reflective surface 170, and a lower mounting element 1110 and an upper mounting element 1120. The lower mounting element 1110 and the upper mounting element 1120 are connected or cooperate with each other to mount and / or support other elements of the lighting device.

[0117] Variations to the disclosed embodiments can become apparent to those of ordinary skill in the art upon reading the foregoing description, with reference to the accompanying drawings. Variations of embodiments disclosed can become apparent to those of ordinary skill in the art upon reading the foregoing description, with reference to the accompanying drawings. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality.

[0118] The mere fact that measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0119] If the term "adapted" is used in the claims and / or specification it should be taken as equivalent to the term "configured" if the term "device" is used in the claims and / or specification it should be taken as equivalent to the term "system", and vice versa.

[0120] The use of any of the claims in the singular does not preclude the multiple use of a claim.

Claims

1. A desk lamp, characterized in that: include: a first lighting device (50A), and A support member (1010), the support member being used to mount the first lighting device, the first lighting device (50A) being a lighting device (50), the lighting device comprising: A light guide plate device (100) and a light source (190), wherein the light guide plate device and the light source are configured to transmit light toward a light transmission window; the light guide plate device comprises: A light guide plate (105) for transmitting light, the light guide plate comprising: a light-transmitting window (110) configured to couple light transmitted by a light source (190) into the light guide plate; and a light exit window (130), the light exit window being configured to couple light out of the light guide plate, the light exit window being at an angle between 80° and 100° relative to the light transmission window; a first reflective surface (120) positioned on the light guide plate and opposite to the light transmission window, for reflecting light incident on the first reflective surface, wherein the light exit window is positioned between the light transmission window and the first reflective surface; a plurality of asymmetric light extraction features (150) for directing light in the light guide plate toward the light exit window, wherein for each asymmetric light extraction feature: The longitudinal axis (159) of the asymmetric light extraction feature is at a non-zero and non-perpendicular angle relative to the light transmission window; and In a first plane (XY), a first side (151) of the asymmetric light extraction feature has a curvature that is smaller than a curvature of a second side (152) of the symmetric light extraction feature, the first plane being a plane parallel to the light exit window, wherein: The first side (151) is located on one side of a second plane, the second plane being a plane perpendicular to the light exit window and passing through the longitudinal axis (159) of the asymmetric light extraction feature; The second side (152) of the asymmetric light extraction feature is located on the other side of the second plane; and The first side is closer to the light-transmitting window than the second side.

2. The desk lamp according to claim 1, characterized in that Each asymmetric light extraction feature (150) is configured such that in a second plane (YZ), the curvature of the first side (151) of the asymmetric light extraction feature is smaller than the curvature of the second side (152) of the asymmetric light extraction feature, the second plane being a plane perpendicular to the light exit window (120) and perpendicular to the light transmission window (110).

3. The desk lamp according to claim 1, characterized in that For each asymmetric light extraction feature, the longitudinal axis is angled between 10° and 50° relative to the light-transmitting window.

4. The desk lamp according to claim 1, characterized in that The plurality of asymmetric light extraction features comprises at least 20 asymmetric light extraction features.

5. The desk lamp according to claim 4, characterized in that: The plurality of asymmetric light extraction features includes at least 100 asymmetric light extraction features.

6. The desk lamp according to claim 1, characterized in that The plurality of asymmetric light extraction features are arranged in a pattern (900) of two or more interwoven or overlapping columns (911, 912, 913).

7. The desk lamp according to claim 1, characterized in that Each asymmetric light extraction feature of the plurality of asymmetric light extraction features is formed by a hole or an indentation in the light guide plate.

8. The desk lamp according to claim 7, characterized in that Each asymmetric light extraction feature of the plurality of asymmetric light extraction features is formed at a surface (160) of the light guide plate (105) opposite to the light exit window.

9. The desk lamp according to claim 1, characterized in that Each asymmetric light extraction feature of the plurality of asymmetric light extraction features has a surface roughness Ra between 0.1 μm and 20 μm.

10. The desk lamp according to any one of claims 1 to 9, characterized in that The light exit window is perpendicular to the light transmission window.

11. The desk lamp according to claim 1, further comprising a second lighting device (50B), wherein the second lighting device is the lighting device (50), The support member is further configured to mount the second lighting device.

12. The desk lamp according to claim 11, characterized in that The plurality of asymmetric light extraction features of the first illuminator are mirrored versions of the plurality of asymmetric light extraction features of the second illuminator.

13. The desk lamp according to any one of claims 11 to 12, characterized in that The support is configured to permit the first and second lighting devices to be positioned at a distance (d) greater than 30 cm from a flat surface (1090) when the support is positioned on the flat surface.

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