Lighting equipment

Abstract

Lighting equipment (IL), equipped with: a light guide plate (1) comprising a first plane (11), a second plane (12) opposite the first plane (11) and substantially parallel to the first plane, a first inclined surface (131) opposite the first plane (11) and inclined to the first plane (11), a second inclined surface (132) positioned between the first inclined surface (131) and the second plane (12), a third inclined surface (133) positioned between the second inclined surface (132) and the second plane (12), a first connecting part (C12) connecting the first inclined surface (131) to the second inclined surface (132), and a second connecting part (C23) connecting the second inclined surface (132) to the third inclined surface (133), wherein the first inclined surface (131), the second inclined surface (132), and the third inclined surfaces (133) are parallel to each other, wherein the first inclined surface (131), the first connecting part (C12),the second inclined surface (132), the second connecting part (C23), the third inclined surface (133) and the second plane (12) are arranged and connected in this order in a first direction (X), and , a light-emitting device (2) comprising a first light-emitting part (161) positioned directly below the first inclined surface (131), a second light-emitting part (162) positioned directly below the second inclined surface (132), and a third light-emitting part (163) positioned directly below the third inclined surface (133), wherein the first light-emitting part (161), the second light-emitting part (162), and the third light-emitting part (163) are configured to emit light with different wavelengths, wherein the lighting device (IL) is characterized in that a section line of the first inclined surface (131) and the first connecting part (C12), a section line of the second inclined surface (132) and the second connecting part (C23), and a section line of the third inclined surface (133) and the second plane (12) lie in the same plane as the second plane (12).

Description

CROSS-REFERENCE TO RELATED REGISTRATION

[0001] The present application claims priority based on Japanese patent application No. 2021-060862, filed on March 31, 2021, and the entire contents of which are quoted herein. Area

[0002] The embodiment of the present invention relates to a lighting device. background

[0003] For example, a light-emitting device is proposed in which a first semiconductor laser element emitting red light, a second semiconductor laser element emitting green light, and a third semiconductor laser element emitting blue light are packaged together. Such light-emitting devices can be used, for example, in lighting devices (backlights) that illuminate, for instance, a liquid crystal display.

[0004] In recent years, the demand for flatter liquid crystal display devices has increased, and thinner lighting devices are in demand.

[0005] WO 2010 050 489 A1 describes a light source device and LCD display. For this device, light from the light source enters the interior of a light guide plate via an incidence angle matching surface and exits from a section area via an adaptation section arranged on a reflective surface.

[0006] JP 2011 138 698 A describes a planar light source device and an LCD display. The planar light source device comprises a light source and a light guide plate that directs the light from the light source and consists of a plate body.

[0007] In JP 2002 270 023 A a surface light source device is described which includes a light plate which has a light guide part for introducing light emitted by white light-emitting diodes.

[0008] US Patent 2008 O 260 328 A1 describes an optical system for backlighting a display. This system comprises a light guide with a limiting direction and a first plurality of light sources arranged near a first edge of the light guide. Light from at least one of the light sources defines an emission axis that runs approximately parallel to the limiting direction.

[0009] US Patent 2009 O 262 283 A1 describes an LCD display. The LCD display comprises a liquid crystal display panel with pixels configured to produce an image, and a lighting system near the liquid crystal display panel designed to illuminate the pixels of the liquid crystal display panel. Brief explanation of the drawings

[0010] It shows: Fig. 1 a view to illustrate a lighting device IL according to an embodiment; Fig. 2 a view that is an example of one in Fig. 1 shows the light-emitting device 2 shown; Fig. 3 a view that is an example of one in Fig. 1 shows the light guide plate 1; Fig. 4 a sectional view showing an example of the lighting device IL; Fig. 5 a top view showing an example of the lighting device IL; Fig. 6 a view that is another example of the in Fig. 1 shows the light guide plate 1; Fig. 7 a sectional view showing another example of the lighting device IL; Fig. 8 a top view showing another example of the lighting device IL. Detailed description

[0011] The present solution is defined by the attached claims. In the following, parts of the description and the drawings relating to earlier embodiments and not necessarily including all features for implementing embodiments of the claimed solution are to be understood as not representing embodiments of the solution, but serving as examples to facilitate understanding of the embodiments of the invention.

[0012] The purpose of the embodiments is to provide a lighting device that can be miniaturized.

[0013] According to an example not covered by the claims, but which contributes to the understanding of the present solution, the lighting device is provided with a light guide plate having a first plane, a second plane opposite the first plane and substantially parallel to the first plane, and an inclined surface opposite the first plane and inclined to the first plane, wherein the inclined surface and the second plane are arranged in a first direction, and a light-emitting device having a first light-emitting part, a second light-emitting part, and a third light-emitting part, which are positioned directly below the inclined surface, are arranged in the first direction, and are configured to emit light with different wavelengths.

[0014] According to another example, which is not covered by the claims but contributes to the understanding of the present solution, the lighting device comprises a light guide plate having a first plane, a second plane opposite the first plane and substantially parallel to the first plane, a first inclined surface opposite the first plane and inclined to the first plane, a second inclined surface positioned between the first inclined surface and the second plane, and a third inclined surface positioned between the second inclined surface and the second plane, wherein the first inclined surface, the second inclined surface, and the third inclined surface are arranged in that order in a first direction, and a light-emitting device comprising a first light-emitting part positioned immediately below the first inclined surface.comprising a second light-emitting part positioned directly below the second inclined surface and a third light-emitting part positioned directly below the third inclined surface, wherein the first light-emitting part, the second light-emitting part and the third light-emitting part are configured to emit light with different wavelengths.

[0015] According to this example, it is possible to provide a lighting system that can be miniaturized.

[0016] Advantageous further developments of the present invention are explained below with reference to the drawings.

[0017] The disclosure is merely an example, and the subject matter that would be readily apparent to a person skilled in the art as a suitable modification while retaining the core of the invention is, of course, included within the scope of the present invention. To further clarify the explanation, the drawings may also schematically show the width, thickness, shape, etc., of the individual parts in comparison to their actual form; however, this is merely an example and does not limit the interpretation of the present invention.

[0018] In the present description and the respective drawings, the components that perform the same or similar functions as those shown in the drawings already mentioned are marked with the same reference symbols, and overlapping detailed explanations may be omitted as appropriate.

[0019] To facilitate understanding, the X, Y, and Z axes, which are orthogonal to each other, are shown in the drawings as needed. The direction along the X axis is called the X direction or first direction, the direction along the Y axis the Y direction or second direction, and the direction along the Z axis the Z direction or third direction. The plane defined by the X and Y axes is called the XY plane, and the plane defined by the X and Z axes the XZ plane. Viewing the XY plane is called the top view. The first direction X and the second direction Y correspond to directions parallel to the main surface of the light guide plate contained in the lighting device, and the third direction Z corresponds to the thickness direction of the light guide plate.

[0020] Fig. Figure 1 shows a view to illustrate a lighting device IL according to one embodiment.

[0021] The lighting device IL is provided with a light guide plate 1 and a light-emitting device 2. The in Fig. The optical fiber 1 and the light-emitting device 2 shown in Figure 1 do not reflect their true shapes, and the details of the optical fiber 1 and the light-emitting device 2 are described later. The light-emitting device 2 is superimposed on one end face of the optical fiber 1. An effective area AA of the optical fiber 1 is an area from which light propagating within the optical fiber 1 is emitted and superimposed on an object 3 to be illuminated. The object 3 to be illuminated, shown in the drawings by dashed lines, is, for example, a liquid crystal display.

[0022] If the liquid crystal display is a translucent panel that displays an image by selectively transmitting illumination, the illumination device IL functions as a backlight. If the liquid crystal display is a reflective panel that displays an image by selectively reflecting illumination, the illumination device IL functions as a frontlight.

[0023] The object 3 to be illuminated is not limited to a liquid crystal display and can be a display board with electrophoretic elements, or a display board to which MEMS (micro electro mechanical systems) is applied.

[0024] A display device can be formed by combining the lighting device IL according to the embodiment and the display panel, which represents the object 3 to be illuminated.

[0025] Fig. 2 shows a view that is an example of the in Fig. Figure 1 shows the light-emitting device 2.

[0026] The light-emitting device 2 is provided with a light-emitting package and a mounting substrate 100 on which the package is mounted. It is also possible to consider the package alone as the light-emitting device 2.

[0027] The packaging comprises a base 110, a lid 120, a lens element 140, a first light-emitting part 161, a second light-emitting part 162, and a third light-emitting part 163. The first light-emitting part 161, the second light-emitting part 162, and the third light-emitting part 163 are housed in an enclosed space formed by the connection between the base 110 and the lid 120.

[0028] The first light-emitting part 161, the second light-emitting part 162, and the third light-emitting part 163 are configured to emit light with different wavelengths. In one example, the first light-emitting part 161 is equipped with a first semiconductor laser element that emits red light, the second light-emitting part 162 is equipped with a second semiconductor laser element that emits green light, and the third light-emitting part 163 is equipped with a third semiconductor laser element that emits blue light.

[0029] In one example, each of the first light-emitting part 161, the second light-emitting part 162, and the third light-emitting part 163 is configured such that it reflects light emitted by each semiconductor laser element onto the lens element 140 via a light-reflecting element, but this is not limited to this configuration. For example, each of the first light-emitting part 161, the second light-emitting part 162, and the third light-emitting part 163 can omit the light-reflecting element and be configured such that each semiconductor laser element emits light directly onto the lens element 140.

[0030] The lens element 140 is bonded to the cover part 120. In one example, the lens element 140 has the form of several interconnected lens parts. A single lens part corresponds to a single light-emitting part, and each lens part transmits the majority of the light emitted by each light-emitting part.

[0031] Fig. Figure 3 shows a view that is an example of the in Fig. 1 shows the light guide plate 1.

[0032] The optical fiber plate 1 has a first plane 11, a second plane 12, and an inclined surface 13. The first plane 11 is a plane parallel to the XY plane. The second plane 12 and the inclined surface 13 are opposite the first plane 11 in the third direction Z. The second plane 12 is a plane essentially parallel to the first plane 11, or the XY plane. The inclined surface 13 is a surface inclined to the first plane 11, or the XY plane. The angle of inclination of the inclined surface 13, i.e., the angle θ1 between the first plane 11 and the inclined surface 13, is an acute angle. The inclined surface 13 and the second plane 12 are aligned in the first direction X. A region of the first plane 11 immediately below the inclined surface 13 (a region that superimposes the inclined surface 13 in the third direction Z) corresponds to a light entry region 11E.

[0033] The light guide plate 1 can be made of glass or plastic.

[0034] The light-emitting device 2 is shown in a simplified, planar view, as indicated by the dashed line. The lens element, etc., is omitted. The multiple light-emitting devices 2 are positioned directly below the inclined surface 13 or the light-entry area 11E and are arranged in the second direction Y. In each of the light-emitting devices 2, the first light-emitting part 161, the second light-emitting part 162, and the third light-emitting part 163 are arranged in that order in the first direction X. Each of the first light-emitting part 161, the second light-emitting part 162, and the third light-emitting part 163 is configured to emit light onto the light-entry area 11E.

[0035] The length L of the inclined surface 13 along the first direction X or the length L of the light entry area 11E along the first direction X is greater than the thickness T of the light guide plate 1 along the third direction Z (L > T).

[0036] The distance D from the first light-emitting part 161 to the third light-emitting part 163 along the first direction X is also greater than the thickness T of the light guide plate 1 (D > T). The thickness T is equal to or less than 1.5 mm, in this example 1.0 mm.

[0037] Fig. Figure 4 shows a sectional view illustrating an example of the lighting device IL. The drawing only shows the main part of the light-emitting device 2, omitting the lens element, etc.

[0038] The lighting device IL is further provided with a reflective layer 5 arranged on the inclined surface 13. The reflective layer 5 is positioned directly above the light-emitting device 2. That is, the first light-emitting part 161, the second light-emitting part 162, and the third light-emitting part 163 are located opposite the reflective layer 5 in the third direction Z. In the illustrated example, the reflective layer 5 is arranged such that it covers almost the entire surface of the inclined surface 13. The reflective layer 5 can also be arranged such that it is positioned only directly above the light-emitting device 2, or only directly above each of the first light-emitting part 161, the second light-emitting part 162, and the third light-emitting part 163.

[0039] Red light emitted by the first light-emitting part 161, green light emitted by the second light-emitting part 162, and blue light emitted by the third light-emitting part 163 each enter from the light entry area 11E and are reflected at the reflective surface 5 or at the interface between the inclined surface 13 and the reflective layer 5. The reflected light of each color is totally reflected at the first plane 11 and propagates inside the light guide plate 1.

[0040] The inclination angle θ1 of the inclined surface 13 is set such that the condition for the light reflected at the reflective layer 5 to be totally reflected at the first plane 11 is met, i.e. the condition for the angle of incidence on the first plane 11 to be greater than the critical angle.

[0041] The light of any color can contain, in addition to the principal light ray essentially parallel to the normal of the light entry area 11E, a divergent component that propagates slightly relative to the normal. It is desirable that the angle of inclination θ1 be set such that both the principal light ray and the divergent component satisfy the condition of total internal reflection.

[0042] Fig. Figure 5 shows a top view illustrating an example of the lighting device IL.

[0043] In a top view, in an area superimposed on the inclined surface 13, red light (R) emitted by the first light-emitting part 161, green light (G) emitted by the second light-emitting part 162, and blue light (B) emitted by the third light-emitting part 163 blend as they propagate along the first direction X. In an area superimposed on the second plane 12, lights emitted by the adjacent light-emitting devices 2 in the second direction Y spread out along the first direction X and blend together.

[0044] In Fig. Figure 5 schematically depicts the propagation of red, green, and blue light; however, with respect to their propagation or directionality in the XY plane, red, green, and blue light are not completely identical. Since the directionality of red, green, and blue light differs, it is desirable for the light with a higher directionality (more difficult to propagate) to be emitted from a position farther from the second plane 12, while the light with a lower directionality (easier to propagate) is emitted from a position near the second plane 12. That is, to the Fig. In the example shown, a combination can be applied such that the light emitted by the first light-emitting part 161 has a high directivity and the light emitted by the third light-emitting part 163 has a low directivity.

[0045] In such an illumination device IL, compared to the edge-illuminated method, in which the first light-emitting part 161, the second light-emitting part 162 and the third light-emitting part 163, which lie in the second direction Y, are opposite the side surface of the light guide plate 1, the distance along the first direction X, which is required to mix light with different wavelengths, can be shortened.

[0046] Furthermore, in the above illumination device IL, compared to the further edge-illuminated method in which the first light-emitting part 161, the second light-emitting part 162 and the third light-emitting part 163, which lie in the third direction Z, are opposite the side surface of the light guide plate 1, the thickness of the light guide plate 1 can be reduced regardless of the distance from the first light-emitting part 161 to the third light-emitting part 163.

[0047] This allows the lighting unit IL to be reduced in size.

[0048] Fig. Figure 6 shows a view that provides another example of the in Fig. The light guide plate shown is shown in Figure 1.

[0049] The optical fiber plate 1 has a first plane 11, a second plane 12, a first inclined surface 131, a second inclined surface 132, and a third inclined surface 133. The first plane 11 is a plane parallel to the XY plane. The second plane 12 is a plane substantially parallel to the first plane 11 or the XY plane. The first inclined surface 131, the second inclined surface 132, the third inclined surface 133, and the second plane 12 are opposite the first plane 11 in the third direction Z.

[0050] The first inclined surface 131, the second inclined surface 132, the third inclined surface 133, and the second plane 12 are arranged in this order along the first direction X. The second inclined surface 132 is positioned between the first inclined surface 131 and the third inclined surface 133, and the third inclined surface 133 is positioned between the second inclined surface 132 and the second plane 12.

[0051] Each of the first inclined surface 131, the second inclined surface 132, and the third inclined surface 133 is inclined to the first plane 11, second plane 12, or XY plane. The angle of inclination of each inclined surface is determined such that the condition of total internal reflection is satisfied, as described above. In one example, the angle of inclination of each inclined surface is the same, and each inclined surface is parallel to, but not restricted to, each of the first inclined surface 131, the second inclined surface 132, and the third inclined surface 133 extends along the second direction Y.

[0052] In the example shown, a connecting piece C12, which connects the first inclined surface 131 and the second inclined surface 132, and a connecting piece C23, which connects the second inclined surface 132 and the third inclined surface 133, each represent a single plane and are inclined to the second plane 12 or XY plane. The shape of the connecting pieces C12 and C23 is not limited to the examples shown.

[0053] In the first level 11, an area immediately below the first inclined surface 131, the second inclined surface 132 and the third inclined surface 133 corresponds to the light entry area 11E.

[0054] The light guide plate 1 can be made of glass or plastic.

[0055] The length L from the first inclined surface 131 to the third inclined surface 133 along the first direction X, or the length L of the light entry area 11E along the first direction X, is greater than the thickness T of the light guide plate 1 along the third direction Z (L > T). The thickness T is equal to or less than 1.5 mm, in this example 1.0 mm.

[0056] The multiple light-emitting devices 2, whose illustration is omitted here, are positioned directly below the light entry area 11E and arranged in the second direction Y, as shown in the Fig. 3 examples shown.

[0057] Fig. Figure 7 shows a sectional view illustrating another example of the lighting device IL. The drawing only shows the main part of the light-emitting device 2, omitting the lens element, etc.

[0058] In each of the light-emitting devices 2, the first light-emitting part 161, the second light-emitting part 162, and the third light-emitting part 163 are arranged in that order in the first direction X. The first light-emitting part 161 is positioned directly below the first inclined surface 131, the second light-emitting part 162 is positioned directly below the second inclined surface 132, and the third light-emitting part 163 is positioned directly below the third inclined surface 133. Each of the first light-emitting part 161, the second light-emitting part 162, and the third light-emitting part 163 is configured such that it emits light onto the light-entry area 11E.

[0059] The lighting device IL is provided with a first reflective layer 151, a second reflective layer 152, and a third reflective layer 153. The first reflective layer 151 is arranged on the first inclined surface 131 and positioned directly above the first light-emitting part 161. The second reflective layer 152 is arranged on the second inclined surface 132 and positioned directly above the second light-emitting part 162. The third reflective layer 153 is arranged on the third inclined surface 133 and positioned directly above the third light-emitting part 163. It is also possible to arrange a single reflective layer from the first inclined surface 131 to the third inclined surface 133.

[0060] The distance D from the first light-emitting part 161 to the third light-emitting part 163 along the first direction X is greater than the thickness T of the light guide plate 1 (D > T).

[0061] Red light emitted from the first light-emitting part 161, green light emitted from the second light-emitting part 162, and blue light emitted from the third light-emitting part 163 each enter through the light entry area 11E. Red light is reflected by the first reflective layer 151, green light is reflected by the second reflective layer 152, and blue light is reflected by the third reflective layer 153. The reflected light of each color is totally reflected at the first layer 11 and propagates inside the light guide plate 1.

[0062] Fig. Figure 8 shows a top view, which shows another example of the lighting device IL.

[0063] In the top view, the first inclined surface 131 superimposes the several first light-emitting parts 161, which are arranged in the second direction Y. Likewise, the second inclined surface 132 superimposes the several second light-emitting parts 162, which are arranged in the second direction Y, and the third inclined surface 133 superimposes the several third light-emitting parts 163, which are arranged in the second direction Y.

[0064] Red light (R) emitted by the first light-emitting part 161, green light (G) emitted by the second light-emitting part 162, and blue light (B) emitted by the third light-emitting part 163 mix together, propagating along the first direction X. In an area superimposed on the second plane 12, lights emitted by the light-emitting devices 2 adjacent in the second direction Y spread out along the first direction X in the second direction Y and mix together.

[0065] In such an example, the same effect as described above can be achieved. Furthermore, compared to the case where the light-emitting devices 2 superimpose a single inclined surface 13, as in the example above, the position of each of the first inclined surface 131, the second inclined surface 132, and the third inclined surface 133 in the third direction Z is not restricted, so that the thickness T of the light guide plate 1 can be made thinner.

[0066] According to the embodiment described above, it is possible to provide a lighting device that can be miniaturized.

[0067] All lighting devices that can be implemented by a person skilled in the art, starting from the lighting device described above as an embodiment of the present invention, by means of a corresponding design modification, also fall within the scope of the present invention, provided that they contain the core of the invention.

[0068] Within the scope of the present invention, a person skilled in the art can derive various examples of modifications, and these examples of modifications are also considered to be part of the scope of the present invention. Subject matter in which a person skilled in the art adds, omits, or changes the design of components to the above-mentioned examples and advantageous embodiments, or adds, omits, or changes the process or its conditions, is also included in the scope of the present invention, as long as the core of the invention remains unchanged.

[0069] It is also understood that other effects brought about by the aspects explained in the above-mentioned examples and advantageous developments are of course brought about by the present invention if they are evident from the information in the present description or can be deduced by the person skilled in the art according to the circumstances.

Claims

[1] Lighting device (IL), equipped with: a light guide plate (1) comprising a first plane (11), a second plane (12) opposite the first plane (11) and substantially parallel to the first plane, a first inclined surface (131) opposite the first plane (11) and inclined to the first plane (11), a second inclined surface (132) positioned between the first inclined surface (131) and the second plane (12), a third inclined surface (133) positioned between the second inclined surface (132) and the second plane (12), a first connecting part (C12) connecting the first inclined surface (131) to the second inclined surface (132), and a second connecting part (C23) connecting the second inclined surface (132) to the third inclined surface (133), wherein the first inclined surface (131), the second inclined surface (132), and the third inclined surfaces (133) are parallel to each other, wherein the first inclined surface (131), the first connecting part (C12),the second inclined surface (132), the second connecting part (C23), the third inclined surface (133) and the second plane (12) are arranged and connected in this order in a first direction (X), and, a light-emitting device (2) comprising a first light-emitting part (161) positioned directly below the first inclined surface (131), a second light-emitting part (162) positioned directly below the second inclined surface (132), and a third light-emitting part (163) positioned directly below the third inclined surface (133), wherein the first light-emitting part (161), the second light-emitting part (162), and the third light-emitting part (163) are configured to emit light with different wavelengths, wherein the lighting device (IL) characterized byis that a line of intersection of the first inclined surface (131) and the first connecting part (C12), a line of intersection of the second inclined surface (132) and the second connecting part (C23), and a line of intersection of the third inclined surface (133) and the second plane (12) lie in the same plane as the second plane (12). [2] Lighting device (IL) according to claim 1, further equipped with: a first reflective layer, which is arranged on the first inclined surface (131) and positioned directly above the first light-emitting part (161), a second reflective layer, which is arranged on the second inclined surface (132) and positioned directly above the second light-emitting part (162), and a third reflective layer, which is arranged on the third inclined surface (133) and positioned directly above the third light-emitting part (163). [3] Lighting device (IL) according to claim 1, wherein the length from the first inclined surface (131) to the third inclined surface (133) along the first direction (X) is greater than the thickness of the light guide plate (1). [4] Lighting device (IL) according to claim 1, wherein the first connecting part (C12) and the second connecting part (C23) are arranged parallel to each other. [5] Lighting device (IL) according to claim 1, wherein the second light-emitting part (162) is positioned between the first (161) and the third light-emitting part (163), and wherein the distance from the first light-emitting part (161) to the third light-emitting part (163) along the first direction (X) is greater than the thickness of the light guide plate (1). [6] Lighting device (IL) according to claim 5, wherein the thickness of the light guide plate (1) is equal to or less than 1.5 mm.

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