Planar illumination device

Abstract

A planar illumination device (1) according to an embodiment comprises a baseboard (20) and a metal frame (10). In the baseboard (20), a plurality of light sources (21) are two-dimensionally arranged on a first surface (20a), and control circuits (23, 24) for controlling lighting of the light sources (21) are disposed on the first surface (20a) and / or a second surface (20b). The metal frame (10) supports the baseboard (20) and is electrically connected to a ground pattern formed on the baseboard (20).

Description

Planar lighting device

[0001] The present invention relates to a surface lighting device.

[0002] A direct-type surface lighting device has a substrate that is approximately the same size as the light-emitting surface, and multiple LEDs (Light Emitting Diodes) are widely arranged on the substrate. Furthermore, the LED driver that operates the LEDs is generally also mounted on the substrate to reduce costs by reducing the number of connecting wires. Therefore, it is required that the substrate side secure the digital signal input required for the LED driver operation and the power input required for the operation of the multiple LEDs.

[0003] Japanese Patent Application Publication No. 5-136578

[0004] However, if the digital signal input and power supply input are sufficiently secured on the board of a direct-type spread illuminating device, radiation noise may occur due to changes in voltage and current, which may affect electromagnetic compatibility (EMC). As a result, there is a concern that this may affect, for example, the performance of the LED driver or the device on which the spread illuminating device is mounted.

[0005] The problem to be solved by the present invention is to provide a surface lighting device capable of maintaining appropriate EMC.

[0006] In order to solve the above-mentioned problems and achieve the object, a planar lighting device according to one aspect of the present invention includes a substrate and a metal frame. The substrate has a first surface on which a plurality of light sources are two-dimensionally arranged, and a control circuit for controlling the lighting of the light sources is arranged on the first surface and / or a second surface. The metal frame supports the substrate and is electrically connected to a ground pattern formed on the substrate.

[0007] FIG. 1 is a diagram illustrating an example of the configuration of a planar lighting device according to an embodiment. FIG. 2 is a diagram illustrating an example of the configuration of a planar lighting device according to an embodiment. FIG. 3A is a diagram illustrating an example of the configuration of a copper foil exposed portion. FIG. 3B is a diagram illustrating an example of the configuration of a copper foil exposed portion. FIG. 3C is a diagram illustrating an example of the configuration of a copper foil exposed portion. FIG. 4 is a diagram illustrating an example of the configuration of a copper foil exposed portion. FIG. 5A is a perspective view of a side grounding member according to Modification 1. FIG. 5B is a diagram illustrating an application example of the side grounding member according to Modification 1. FIG. 6A is a diagram illustrating an example of the configuration of a copper foil exposed portion according to Modification 2. FIG. 6B is a diagram illustrating an example of the configuration of a copper foil exposed portion according to Modification 2. FIG. 6C is a diagram illustrating an example of the configuration of a copper foil exposed portion according to Modification 2. FIG. 7 is a diagram illustrating an example of the configuration of a copper foil exposed portion according to Modification 3.

[0008] Hereinafter, a surface lighting device according to an embodiment will be described with reference to the drawings. Note that the present invention is not limited to these embodiments. Furthermore, the dimensional relationships and ratios of elements in the drawings may differ from reality. The dimensional relationships and ratios may differ between the drawings. Furthermore, the content described in one embodiment or modification is, in principle, applicable to other embodiments or modifications as well.

[0009] 1 and 2 are diagrams showing an example of the configuration of a planar lighting device 1 according to an embodiment. FIG. 1 shows a perspective view of a metal frame 10, a substrate 20, and a reflector plate 30 provided in the planar lighting device 1. FIG. 2 shows a perspective view of the rear surface 20b of the substrate 20. For convenience, the bottom surface of the planar lighting device 1 is in the X-Y plane, and the thickness direction of the planar lighting device 1 is defined as the Z-axis direction. The longitudinal direction of the planar lighting device 1 is defined as the X-axis direction, and the lateral direction is defined as the Y-axis direction. Although not shown, an optional optical film or top frame may be provided on the exit side of the reflector plate 30 as appropriate.

[0010] The metal frame 10 is a housing (bottom frame) that houses (supports) the substrate 20 and the reflector plate 30. The metal frame 10 is, for example, a die-cast frame made of a non-ferrous metal such as magnesium or aluminum, or a sheet metal made of aluminum or stainless steel.

[0011] The metal frame 10 also has holes 11, 12, and 13 through which a connector 22 and LED (Light Emitting Diode) drivers 23 and 24, which will be described later, are inserted to the outside of the device. The metal frame 10 is also electrically connected to a ground pattern formed on the substrate 20. The configuration related to this connection will be described later with reference to Figures 3A to 4.

[0012] The substrate 20 has a plurality of light sources 21 arranged two-dimensionally on a front surface 20a. The substrate 20 is, for example, a printed circuit board (PCB). The substrate 20 also has a connector 22, LED drivers 23 and 24, and exposed copper foil portions 25, 26, 27, and 28 on a rear surface 20b. The connector 22 and the LED drivers 23 and 24 may be arranged on the front surface 20a of the substrate 20, or on either the rear surface 20b or the front surface 20a.

[0013] The terms "front surface 20a" and "rear surface 20b" are merely defined for convenience, with the surface on which the light source 21 is disposed being the "front" and the surface on which the light source 21 is not disposed being the "rear," and the present invention is not limited by these definitions. The front surface 20a is also referred to as the "first surface," and the rear surface 20b is also referred to as the "second surface." The "first surface" and the "second surface" are surfaces that face each other.

[0014] The light source 21 is, for example, an LED. The connector 22 is connected to, for example, a power supply line, a signal line, a ground, etc. The LED drivers 23, 24 are, for example, integrated circuits (ICs) that control the lighting of the light source 21. Each light source 21 is individually driven by the LED drivers 23, 24, and its light emission is individually controlled, thereby supporting so-called local dimming.

[0015] The exposed copper foil portions 25, 26, 27, and 28 correspond to ground terminals formed by exposing the ground pattern on the back surface 20b of the substrate 20, which is covered with resist. The ground pattern is formed of, for example, copper foil. In other words, the exposed copper foil portions 25, 26, 27, and 28 are examples of exposed portions where the copper foil ground terminals are exposed.

[0016] The copper foil exposed portions 25, 26, 27, and 28 are arranged discretely on the rear surface 20b and are electrically connected directly or indirectly to the metal frame 10. The configuration relating to this connection will be described later with reference to Figures 3A to 4.

[0017] The reflector plate 30 includes a frame 31 and reflective walls 32 that reflect light from the multiple light sources, and is formed of, for example, an insulating white resin. The reflective walls are arranged, for example, in a grid pattern between each of the multiple light sources, forming multiple reflective surfaces that surround each of the multiple light sources. The height of the reflective walls 32 and the angle of the reflective surfaces may be configured as desired. For example, the height of the reflective walls 32 may be different in the X-axis direction and the Y-axis direction.

[0018] 1 and 2 are merely examples, and the present invention is not limited to the illustrated contents. For example, the surface lighting device 1 is not limited to a rectangle, and may be a partially curved rectangle, or may be any shape, such as a circle, an ellipse, or a polygon. The shapes of the metal frame 10, the substrate 20, and the reflector plate 30 can also be configured arbitrarily depending on the shape of the surface lighting device 1. Furthermore, the metal frame 10, the substrate 20, and the reflector plate 30 may be provided with appropriate notches or the like to fix their positions relative to one another.

[0019] 3A, 3B, and 3C are diagrams showing configuration examples of the copper foil exposed portion 25. Fig. 3A shows an enlarged view of the copper foil exposed portion 25. Fig. 3B shows an enlarged view of a portion of the metal frame 10 facing the copper foil exposed portion 25. Fig. 3C shows a cross-sectional view in the XZ plane passing through the center of the copper foil exposed portion 25. Note that a configuration example of the copper foil exposed portion 26 is the same as that of the copper foil exposed portion 25, and therefore is not shown in the figures.

[0020] A screw fastening hole 25a is formed in the copper foil exposed portion 25. The hole 25a penetrates the front surface 20a and the back surface 20b at the center of the copper foil exposed portion 25. The hole 25a is also formed near the center in the longitudinal direction of the substrate 20. Specifically, the hole 25a is formed along a "reference side" that serves as a reference in the configuration of the surface lighting device 1, among the sides parallel to the longitudinal direction of the substrate 20.

[0021] The screw fastening holes 25a are formed along the reference edge to reduce the effect of differences in the linear expansion coefficients of the substrate 20 and the reflector plate 30. For example, under typical operating conditions, the linear expansion coefficients of the substrate 20 and the reflector plate 30 are different, which can cause variations in the lengths of the substrate 20 and the reflector plate 30 depending on temperature. Such variations can cause a change in the positional relationship between the individual light sources 21 arranged on the substrate 20 and the reflective surface of the reflector plate 30, or can cause the reflector plate 30 to become dislodged from the substrate 20, potentially resulting in a degradation of the performance of the surface lighting device 1. Therefore, to mitigate such effects, particularly in the longitudinal direction where variations are greatest, the reference edge serving as the reference for the configuration is set along the longitudinal direction, and the device is designed to be fastened with screws near the center of the reference edge. In other words, the surface lighting device 1 typically has a screw fastening position near the center of the reference edge, and the copper foil exposed portion 25 serving as a ground terminal is provided at this position.

[0022] Furthermore, solder 25b (the hatched portion in FIG. 3A ) is formed on the exposed copper foil portion 25 to improve contact with the metal frame 10. The solder 25b is formed on the surface of the ground terminal, and in order to ensure proper contact with the metal frame 10, the solder 25b is layered at appropriate intervals with an appropriate amount and thickness using, for example, a metal mask.

[0023] The bottom surface of the metal frame 10 is provided with contact portions 14 that come into contact with the exposed copper foil portion 25 ( FIG. 3B ). The contact portions 14 have a recessed structure to accommodate the thickness of the solder 25b. The contact portions 14 also have holes 14a for screw fastening and protrusions 14b to suppress changes in the height of the board 20 due to screw fastening. The protrusions 14b are preferably provided at positions facing the exposed copper foil portion 25 and are discretely arranged to surround the holes 14a.

[0024] The metal frame 10, the substrate 20, and the reflector plate 30 are fastened together by screws 40 (FIG. 3C). The reflector plate 30 has female-threaded screw holes 33 into which the screws 40 are fastened. The screw holes 33 are formed in the reflecting wall 32.

[0025] The screw 40 is inserted through the hole 14a, the hole 25a, and the screw hole 33 in that order, and is fastened to the female thread of the screw hole 33, thereby fixing the metal frame 10, the substrate 20, and the reflector plate 30 together (FIG. 3C).

[0026] As described above, when two (or more) copper foil exposed portions 25, 26 are provided to be fixed by screw fastening, it is preferable to provide them on both sides of the longitudinal center. That is, as shown in Fig. 2, it is preferable that the copper foil exposed portion 25 (screw fastening hole 25a) is provided on the positive X-axis side from the longitudinal center (X-axis direction), and the copper foil exposed portion 26 (screw fastening hole 26a (not shown)) is provided on the negative X-axis side from the longitudinal center.

[0027] Fig. 4 is a diagram showing an example of the configuration of the copper foil exposed portion 27. Fig. 4 shows an enlarged view of the copper foil exposed portion 27. Note that an example of the configuration of the copper foil exposed portion 28 is the same as that of the copper foil exposed portion 27, and therefore is not shown in the figure.

[0028] A conductive tape 27a is provided on the copper foil exposed portion 27. The conductive tape 27a is a fixing member (double-sided tape) that is conductive and adhesive. The copper foil exposed portion 27 is electrically connected to the metal frame 10 via the conductive tape 27a.

[0029] Furthermore, it is preferable that the conductive tape 27a be disposed near the end in the longitudinal direction of the substrate 20. As a result, the copper foil exposed portion 27 can be disposed at a position separated from the copper foil exposed portion 25. It is also preferable that the copper foil exposed portion 27 be disposed at a position separated from the copper foil exposed portion 25 in the lateral direction.

[0030] 3A, 3B, 3C, and 4 are merely examples, and the present invention is not limited to the illustrated contents. For example, in the above example, the copper foil exposed portions 25, 26, 27, and 28 are indirectly electrically connected to the metal frame 10 via the solder 25b or the conductive tape 27a, but they may be directly connected.

[0031] In the above example, the contact portion 14 has a recessed structure, but it does not necessarily have to be recessed, and may be protruding.

[0032] In the above example, the screw holes 33 are formed in the reflecting wall 32, but they may be formed in the frame of the reflector plate 30. In other words, the screw holes 33 can be formed in at least one of the frame of the reflector plate 30 and the reflecting wall 32.

[0033] Furthermore, the screw holes 33 may be provided in, for example, a dedicated member for forming female threads, instead of the reflector plate 30. This dedicated member is preferably positioned so as not to interfere with other members, such as the reflector plate 30.

[0034] As described above, in the surface lighting device 1 according to the embodiment, the metal frame 10 is electrically connected to the ground pattern formed on the substrate 20. This allows the surface lighting device 1 to appropriately maintain electromagnetic compatibility (EMC).

[0035] For example, the surface lighting device 1 can ensure a reliable ground connection while suppressing an increase in the number of parts by exposing the ground terminal at a screw fastening position near the center of the reference side. Furthermore, the surface lighting device 1 can provide a plurality of discrete ground connection points by making a ground connection via conductive tape 27a near the longitudinal end.

[0036] (Modification 1) In addition to the copper foil exposed portions 25, 26, 27, and 28 described in the above embodiment, for example, a side grounding member 50 may be used for ground connection.

[0037] The side grounding member 50 is a conductive member that is electrically connected to the ground pattern on the surface 20a of the substrate 20 and can be electrically connected to the wall surface of the metal frame 10. As the side grounding member 50, for example, OGSC-756030 manufactured by Kitagawa Industries Co., Ltd. can be used.

[0038] Fig. 5A is a perspective view of a side grounding member 50 according to Modification 1. Fig. 5B is a diagram showing an application example of the side grounding member 50 according to Modification 1. Fig. 5B shows an enlarged view of the side grounding member 50 arranged on the front surface 20a of the substrate 20.

[0039] 5A , the side grounding member 50 includes a main body portion 51 and a spring portion 52. The main body portion 51 is a conductive housing and can accommodate the spring portion 52. The spring portion 52 is attached to the main body portion 51 and is accommodated inside the main body portion 51 by being pressed toward the main body portion 51.

[0040] 5B , the side grounding member 50 is disposed on the surface 20a near an end of the substrate 20 in the longitudinal direction, and is electrically connected to a ground pattern formed on the substrate 20. For example, the side grounding member 50 is electrically connected to the ground pattern by a through-hole. The side grounding member 50 is then housed in the metal frame 10 while disposed on the surface 20a. At this time, the spring portion 52 of the side grounding member 50 is pressed toward the main body portion 51 by the side wall of the metal frame 10, and is housed inside the main body portion 51. As a result, the side grounding member 50 electrically connects the ground pattern of the substrate 20 to the side wall of the metal frame 10.

[0041] (Modification 2) While the copper foil exposed portions 25, 26, 27, and 28 described in the above embodiment are circular, they may be configured in any shape. As an example, a case where the copper foil exposed portion 26 is configured in various shapes will be described.

[0042] 6A, 6B, and 6C are diagrams showing an example of the configuration of the copper foil exposed portion 26 according to Modification 2. Enlarged views of the copper foil exposed portion 26 are shown in FIGS.

[0043] 6A is configured, for example, in a semicircular shape. The copper foil exposed portion 26 has a notch 26a and solder 26b formed therein. The notch 26a maintains a positional relationship with the bottom surface of the metal frame 10. The solder 26b is configured in a semicircular shape to match the shape of the copper foil exposed portion 26. Then, like the copper foil exposed portion 25, the copper foil exposed portion 26 is firmly fixed (fastened) to the metal frame 10 by a screw inserted therein. This ensures that the copper foil exposed portion 26 is grounded to the metal frame 10.

[0044] The copper foil exposed portion 26 shown in Fig. 6B is configured, for example, in a U-shape. A notch 26a and solder 26b are formed in the copper foil exposed portion 26. The notch 26a is similar to the notch 26a in Fig. 6A, so a description thereof will be omitted. The solder 26b is configured in a U-shape to match the shape of the copper foil exposed portion 26.

[0045] The copper foil exposed portion 26 shown in Fig. 6C is configured, for example, in a linear shape. The copper foil exposed portion 26 has a notch 26a and solder 26b formed therein. The notch 26a is similar to the notch 26a in Fig. 6A, so a description thereof will be omitted. The solder 26b is configured in a linear shape to match the shape of the copper foil exposed portion 26.

[0046] As described above, the copper foil exposed portion 26 may have any one of the shapes of a circle, a semicircle, a U-shape, and a straight line. In addition to the shapes shown in the drawings, the copper foil exposed portion 26 may have any shape, such as an L-shape, a U-shape, or an ellipse. This allows the planar lighting device 1 according to the second modification to have greater design freedom.

[0047] For example, depending on the size and shape of the surface lighting device 1 and the positional relationship with other components provided on the substrate 20, the copper foil exposed portion 25 may need to be provided near the edge of the substrate 20, which may make it difficult to form a circular copper foil exposed portion 25 with a hole 25a in the center. However, even in such cases, if the copper foil exposed portion 26 has a notch 26a, it can be formed near the edge of the substrate 20.

[0048] In Modification 2, the copper foil exposed portion 26 is formed in a different shape from the copper foil exposed portion 25, but the present invention is not limited to this. For example, each of the copper foil exposed portions 25, 26, 27, and 28 can be formed in any shape. However, when the copper foil exposed portion 25 and the copper foil exposed portion 26 are provided at positions the same distance from the edge of the substrate 20, it is preferable that they be formed in the same shape.

[0049] In addition, in the second modification, the copper foil exposed portion 26 is described as being fixed (fastened) by a screw to provide a reliable (solid) ground connection to the metal frame 10. However, the copper foil exposed portion 26 may be fixed by a protrusion (a pin of a size equivalent to the screw 40) provided on the metal frame 10, or may be fixed by conductive tape. When the copper foil exposed portion 26 is fixed by conductive tape, the notch 26a does not need to be provided.

[0050] (Variation 3) In the above embodiment, the case where the contact portion 14 having a recessed structure is provided in the metal frame 10 has been described, but if the metal frame 10 is made of sheet metal, it is difficult to provide a recessed structure to absorb the thickness of the solder 25 b. Therefore, a preferred configuration for this case will be described.

[0051] 7 is a diagram showing an example of the configuration of the copper foil exposed portion 25 according to Modification 3. FIG. 7 shows an enlarged view of the copper foil exposed portion 25.

[0052] Holes 25a for screw fastening are formed in the copper foil exposed portion 25. The holes 25a are similar to the holes 25a described in the above embodiment, and therefore a description thereof will be omitted.

[0053] Furthermore, the copper foil exposed portion 25 is plated with a ring-shaped plating 25c (the hatched portion in FIG. 7) on the surface of the copper foil so as to surround the hole 25a. The plating 25c is applied to prevent corrosion of the copper foil exposed from the resist. Specifically, this is because there is a concern that corrosion will increase contact resistance and reduce the effectiveness of the electrical continuity (EMC) countermeasures. For example, a corrosion-resistant material with low electrical resistance, such as gold plating or gold-nickel alloy plating, is suitable for the plating 25c.

[0054] Furthermore, a conductive tape 25d is provided on the copper foil exposed portion 25. The conductive tape 25d is a fixing member (double-sided tape) that is conductive and adhesive, and is formed in a ring shape so as to surround the hole 25a. The copper foil exposed portion 25 is electrically connected to the metal frame 10 via the conductive tape 25d.

[0055] Although not shown, the contact portion 14 of the bottom surface of the metal frame 10 with which the conductive tape 25d comes into contact is flat (i.e., at the same height as the rest of the bottom surface) because it is difficult to provide a recessed structure in the case of sheet metal as described above. However, if possible, the contact portion 14 may be recessed or protruding.

[0056] In this way, when the metal frame 10 is formed from sheet metal, it becomes difficult to provide a recessed structure to absorb the thickness of the solder 25b, so it is preferable to use conductive tape 25d, which is thin and easy to control the thickness, instead of solder 25b.

[0057] 7 has been described for the copper foil exposed portion 25, but the same configuration can be applied to the copper foil exposed portions 26, 27, and 28. Furthermore, for the copper foil exposed portions 27 and 28, plating 25c may be used between the copper foil and the conductive tape instead of screw fastening. Furthermore, the shape of the copper foil exposed portion 25 (screw fastening hole 25a) according to Modification 3 is not limited to a circular shape, and may be a shape other than a circular shape as shown in FIGS. 6A, 6B, and 6C.

[0058] 7, the case where plating 25c is applied to the surface of the copper foil has been described, but plating 25c does not necessarily have to be applied. In this case, conductive tape 25d is directly provided on the surface of the copper foil.

[0059] 7, for convenience of illustration, the conductive tape 25d is described as being smaller than the plating 25c, but this is not limited to this. The conductive tape 25d may be approximately the same size as the plating 25c, or may be larger than the plating 25c.

[0060] The term "exposed portion" used in the above embodiments and modifications is intended to indicate that the exposed portion is electrically exposed from the resist (exposed as a ground terminal), and is not intended to indicate that the exposed portion is spatially exposed without contact with other objects. In other words, solder, conductive tape, plating, or the like may be provided on the exposed portion as appropriate to allow it to function as a ground terminal or to prevent its function from being impaired.

[0061] In the above embodiment and modified example, the ground terminal (exposed copper foil portions 25, 26) is disposed near the center of the reference side, but this is not limiting. For example, if the length of the substrate 20 (reflector plate 30) is short, it is preferable to provide the ground terminal at one end of the reference side, rather than near the center of the reference side.

[0062] Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to the above and various modifications are possible without departing from the spirit of the present invention.

[0063] As described above, the surface lighting device according to the embodiment includes a substrate on which a plurality of light sources are two-dimensionally arranged on a first surface and control circuits (LED drivers 23, 24) for controlling the lighting of the light sources are arranged on the first surface and / or second surface, and a metal frame that supports the substrate and is electrically connected to a ground pattern formed on the substrate. This allows the surface lighting device 1 to maintain appropriate EMC.

[0064] The second surface also has an exposed portion where the copper foil ground terminal is exposed, thereby enabling the surface lighting device to connect the second surface of the substrate to the metal frame via ground.

[0065] Furthermore, the surface of the exposed portion is covered with plating, which prevents corrosion of the copper foil exposed from the resist in the spread illuminating device, thereby maintaining appropriate EMC.

[0066] Furthermore, the exposed portions are arranged discretely on the second surface, thereby enabling the surface lighting device to be efficiently connected to ground.

[0067] The substrate has a hole at the center of the exposed portion that penetrates the first and second surfaces, and is fixed to the metal frame by a screw that passes through the hole. This allows the surface lighting device to be fixed at the ground connection point by screw fastening.

[0068] The holes are formed near the center of the substrate in the longitudinal direction, which reduces the influence of the difference in linear expansion coefficient between the substrate 20 and the reflector plate 30 on the surface illumination device.

[0069] The hole is formed near the center of the reference side of the surface lighting device, so that the surface lighting device can be provided with a ground terminal by utilizing the screw fastening position near the center of the reference side.

[0070] The planar lighting device further includes a reflector plate having reflective walls that reflect light from the multiple light sources, and the screws secure the metal frame, the substrate, and the reflector plate together, thereby enabling the planar lighting device to firmly fasten the metal frame, the substrate, and the reflector plate together with the screws.

[0071] The reflector plate also has female-threaded screw holes for fastening screws, which allows the metal frame, substrate, and reflector plate to be fastened together by screws without increasing the number of parts in the planar lighting device.

[0072] The screw holes are formed in at least one of the frame of the reflector plate and the reflective wall, thereby enabling the planar lighting device to fasten the metal frame, substrate, and reflector plate together with screws without increasing the number of parts.

[0073] The exposed portion is electrically connected to the metal frame via solder formed on the surface of the ground terminal, thereby improving the adhesion between the metal frame and the substrate of the planar lighting device.

[0074] The exposed portion is electrically connected to the metal frame via a fixing member that is conductive and adhesive, thereby improving the adhesion between the metal frame and the substrate of the planar lighting device.

[0075] The fixing member is disposed near an end of the substrate in the longitudinal direction, thereby enabling the planar lighting device to have a plurality of exposed portions disposed discretely.

[0076] The metal frame has a protrusion at a position facing the exposed portion, which makes it possible to prevent the height of the substrate from changing due to screw fastening in the planar lighting device.

[0077] The exposed portion has any one of a circular, semicircular, U-shaped, and linear shape, thereby enabling the surface illumination device to be efficiently connected to the ground.

[0078] The planar lighting device further includes, on the first surface, a conductive member electrically connected to the ground pattern and electrically connectable to a wall surface of the metal frame, thereby enabling the planar lighting device to be efficiently connected to the ground.

[0079] Furthermore, the plurality of light sources can be dimmed.

[0080] The substrate has a hole at the center of the exposed portion that penetrates through the first and second surfaces, and is fixed to the metal frame by a screw that passes through the hole, the surface of the exposed portion is covered with plating, and a fixing member that is conductive and adhesive is provided between the plating and the metal frame. This makes it possible to maintain appropriate EMC even when the metal frame is made of sheet metal and it is difficult to provide a recessed structure to accommodate the thickness of the solder.

[0081] Furthermore, the present invention is not limited to the above-described embodiments. Configurations in which the above-described components are appropriately combined are also included in the present invention. Furthermore, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-described embodiments, and various modifications are possible.

[0082] 1 Planar lighting device, 10 Metal frame, 11, 12, 13, 14a, 25a Hole, 14 Contact portion, 14b Protrusion, 20 Substrate, 20a Surface, 20b Back surface, 21 LED, 22 Connector, 23, 24 LED driver, 25, 26, 27, 28 Copper foil exposed portion, 25c Plating, 26b Solder, 25d, 27a Conductive tape, 30 Reflector plate, 31 Frame, 32 Reflective wall, 33 Screw hole, 40 Screw, 50 Side ground member

Claims

1. A surface lighting device comprising: a substrate on which a plurality of light sources are arranged two-dimensionally on a first surface, and a control circuit for controlling the lighting of the light sources is arranged on said first surface and / or second surface; and a metal frame that supports said substrate and is electrically connected to a ground pattern formed on said substrate.

2. The spread illuminating device according to claim 1, wherein the second surface has an exposed portion where a copper foil ground terminal is exposed.

3. The spread illuminating device according to claim 2, wherein the surface of the exposed portion is covered with plating.

4. The surface lighting device according to claim 2, wherein a plurality of the exposed portions are discretely arranged on the second surface.

5. A surface lighting device as described in claim 2, wherein the substrate has a hole at the center of the exposed portion that penetrates the first surface and the second surface, and is fixed to the metal frame by a screw that passes through the hole.

6. The surface illumination device according to claim 5, wherein the hole is formed near the center of the substrate in the longitudinal direction.

7. A surface lighting device according to claim 5, wherein the hole is formed near the center of a reference side of the surface lighting device.

8. The planar lighting device according to claim 5, further comprising a reflector plate having reflective walls that reflect light from the plurality of light sources, and wherein the screws secure the metal frame, the substrate, and the reflector plate together.

9. The spread illuminating device according to claim 8, wherein the reflector plate has screw holes with female threads formed therein into which the screws are fastened.

10. The planar lighting device according to claim 9, wherein the screw holes are formed in at least one of the frame of the reflector plate and the reflecting wall.

11. The spread illuminating device according to claim 2, wherein the exposed portion is electrically connected to the metal frame via solder formed on the surface of the ground terminal.

12. A surface lighting device according to claim 2 or 3, wherein the exposed portion is electrically connected to the metal frame via a fixing member that is conductive and adhesive.

13. The planar lighting device according to claim 12, wherein the fixing member is disposed near an end of the substrate in the longitudinal direction.

14. The spread illuminating device according to claim 2, wherein the metal frame has a protrusion at a position facing the exposed portion.

15. The spread illuminating device according to claim 2, wherein the exposed portion has any one of a circular, semicircular, U-shaped, and linear shape.

16. The surface lighting device according to claim 1, further comprising a conductive member on the first surface, electrically connected to the ground pattern and electrically connectable to a wall surface of the metal frame.

17. The planar lighting device according to claim 1, wherein the plurality of light sources are capable of being dimmed.

18. A surface lighting device as described in claim 2, wherein the substrate has a hole at the center of the exposed portion that penetrates the first surface and the second surface, and is fixed to the metal frame by a screw that passes through the hole, the surface of the exposed portion is covered with plating, and a fixing member that is conductive and adhesive is provided between the plating and the metal frame.

Images