JP2010147012A - Planar light source, and display lighting fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to input relatively large power to a semiconductor light emitting element and control rise of a junction temperature of the semiconductor light emitting element with constraint of applicable environment minimized. <P>SOLUTION: The planar light source A is provided with a plurality of light-emitting diodes 11 mounted on a substrate 12, a substrate holder 13 holding the substrate 12 and thermally-coupled with the substrate 12, a light guide plate 20 having an incident face 20a or a circumferential face, where light from the light emitting diodes 11 enters and a light emitting face 20b or a face crossing the circumferential face, and a back plate 30 made of a metal plate, arranged opposed to a rear face of the light emitting face 20b on the light guide plate 20. The substrate holder 13 is provided with a back piece 13c superimposing and thermally-coupling with one end part of one face in a thickness direction of the back plate 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface light source device that can be used as a surface light source, which is a light source device configured by combining a light emitting plate with a semiconductor light emitting element that is a light emission source, and a display lighting apparatus that uses the surface light source device as a light source. is there.

  Conventionally, it has been considered to use a surface light source device as a light source of a display luminaire such as an automobile tail lamp, guide light, or advertisement light.

  For example, as a structure of a guide lamp, a structure in which a translucent display panel receives light directly or indirectly from a cold cathode lamp as a light emission source is known (for example, see Patent Document 1). Patent Document 1 does not specify that a surface light source is configured by a light guide plate as a configuration for introducing light from a cold cathode lamp into a display panel, but a configuration in which a cold cathode lamp is disposed above a display panel. From the above, it is considered that a light source device in which a light emitting region is formed in a planar shape using a light guide plate is assumed.

  By the way, in the technique of patent document 1, since the high frequency electric power is supplied from the lighting unit and the cold cathode lamp is turned on at a high frequency, if the power supply line connecting the lighting unit and the light source is not shortened, There is a problem that the light output is reduced due to the influence of the stray capacitance. Also, since a high voltage is required for starting the cold cathode lamp, it is necessary to stop the entire circuit when an abnormality occurs in the cold cathode lamp. Further, since noise is generated from the lighting unit and the cold cathode lamp, it is necessary to take countermeasures against malfunctions if an attempt is made to use the remote control device when checking the circuit of the lighting unit or the like.

  As a configuration for solving this type of problem, a configuration using a light-emitting diode as a light-emitting source, as described in FIGS. 21 and 25 of Patent Document 2, can be considered. If the light-emitting source is a light-emitting diode, it can be lit by direct current and a high voltage for starting is not required, so that the above-described problem can be solved.

  In the configuration described in Patent Document 2, a plurality of light-emitting diodes mounted on a substrate are used as a light-emitting source, and one of the four peripheral surfaces of the light guide plate having a rectangular front shape is used as an incident surface. A surface light source device having a configuration in which light is incident and light is emitted from an emission surface that is one surface in the thickness direction of the light guide plate is realized.

Light-emitting diodes that can be used as a light-emitting source can be broadly classified into a shell type adopted in Patent Document 3 and a surface mount type adopted in Patent Document 4. Since bullet-type light emitting diodes have less total luminous flux than input light emitting diodes compared to surface mounted light emitting diodes, using surface mounted light emitting diodes reduces the number of light emitting diodes mounted and reduces manufacturing costs. Can do. In particular, since a surface-mount type light emitting diode having a high light output has been provided recently, it is possible to further reduce the number of light emitting diodes mounted on the light output from the surface light source device.
JP 2001-14909 A JP 2004-39289 A Japanese Patent Application Laid-Open No. 8-160892 JP 2008-98190 A

  By the way, the maximum usable temperature of the light emitting diode is determined by the upper limit value (maximum junction temperature) of the junction temperature which is the temperature of the PN junction. In other words, it is necessary to limit the operating temperature so as not to exceed the maximum junction temperature. On the other hand, by devising to keep the junction temperature low, it is possible to extend the lifetime until the brightness is lowered and lighting is impossible, and high reliability as a light emitting source can be obtained.

  As a technique for lowering the junction temperature, a technique for reducing the input power of the light emitting diode and a technique such as water cooling or air cooling for lowering the ambient temperature of the light emitting diode are considered.

  However, when a technique for reducing the input power to the light emitting diode is adopted, the light output per one is lowered, so that the number of mounted parts increases, leading to an increase in manufacturing cost. On the other hand, when the technology for lowering the ambient temperature is adopted, there are problems that the usable environment is limited and that the surface light source device as a whole is increased in size.

  The above-described problem also occurs when a semiconductor light emitting element other than a light emitting diode, such as a semiconductor laser or an organic EL, is used as a light source.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a junction of a semiconductor light emitting device while allowing relatively large electric power to be input to the semiconductor light emitting device and reducing restrictions on the usable environment. The object is to provide a small surface light source device that suppresses an increase in temperature, and further to provide a display lighting apparatus using the surface light source device.

  According to the first aspect of the present invention, a plurality of semiconductor light emitting devices mounted on a substrate, a substrate holder that holds the substrate and is thermally coupled to the substrate, and light from the semiconductor light emitting device is incident on at least a part of the peripheral surface. A light guide plate having an incident surface and one surface in the thickness direction as an output surface, and a back plate that is a metal plate covering the other surface in the thickness direction of the light guide plate, and the substrate holder has a back plate on one surface in the thickness direction of the back plate And a heat transfer piece that is thermally coupled to the back plate.

  According to a second aspect of the present invention, a plurality of semiconductor light emitting devices mounted on a substrate, a substrate holder that holds the substrate and is thermally coupled to the substrate, and light from the semiconductor light emitting device is incident on at least a part of the peripheral surface. A light guide plate that has an incident surface and one surface in the thickness direction as an output surface, and a back plate that is a metal plate that covers the other surface in the thickness direction of the light guide plate, and the back plate is formed integrally with the substrate holder. It is characterized by.

  The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, a white reflective film is formed on a surface of the back plate facing the light guide plate.

  According to a fourth aspect of the present invention, a plurality of semiconductor light emitting devices mounted on a substrate, a substrate holder that holds the substrate and is thermally coupled to the substrate, and light from the semiconductor light emitting device is incident on at least a part of the peripheral surface. A light guide plate having an incident surface and a light exit surface as one surface in the thickness direction, and a metal outer frame that surrounds the entire circumference of the light guide plate together with the substrate holder. The outer frame is integrated with the outer frame. It is characterized by being formed.

  According to a fifth aspect of the present invention, a plurality of semiconductor light emitting devices mounted on a substrate, a substrate holder that holds the substrate and is thermally coupled to the substrate, and light from the semiconductor light emitting device is incident on at least a part of the peripheral surface. A light guide plate having an incident surface and one surface in the thickness direction as an output surface, an outer frame surrounding the entire periphery of the light guide plate together with the substrate holder, and covering the other surface in the thickness direction of the light guide plate and closing one surface of the outer frame And a metal box having an integrated back plate, and the box is formed integrally with the substrate holder.

  A sixth aspect of the present invention is a display lighting fixture, comprising the surface light source device according to any one of the first to fifth aspects, and a fixture main body to which the surface light source device is attached.

  According to the configuration of the present invention, in a surface light source device that uses a semiconductor light emitting element as a light emitting source and performs surface light emission by using a light guide plate, the back plate that covers the back surface of the light guide plate as a heat radiating member of the semiconductor light emitting element In the surface light source device using the light guide plate, at least one of the back plate and the outer frame is thermally coupled to the semiconductor light emitting element so that at least one of the outer frame surrounding the peripheral surface of the light guide plate can be used. It is possible to increase the heat dissipation area for radiating the heat from the semiconductor light emitting element while avoiding substantial enlargement, and as a result, relatively large power can be input to the semiconductor light emitting element, In addition, there is an advantage that it is possible to reduce restrictions on the usable environment.

  According to the configuration of the first aspect of the present invention, since the back plate that covers one surface in the thickness direction of the light guide plate is used for heat dissipation of the semiconductor light emitting device, the increase in the size of the thickness of the back plate does not substantially increase the size. A large heat dissipation area can be secured. Further, by covering one surface in the thickness direction of the light guide plate with the back plate, light leakage to the back of the light guide plate can be prevented, and the back plate can be used for both a heat dissipation function and an optical function. In addition, since the heat transfer piece of the substrate holder and a part of the back plate are overlapped, the cross-sectional area of the part involved in heat conduction can be increased between the substrate holder and the back plate. Despite the fact that the back plate is separate, heat transfer can be performed efficiently.

  According to the configuration of the second aspect of the present invention, the back plate that covers one surface in the thickness direction of the light guide plate is used for heat dissipation of the semiconductor light emitting device, so that the size increase of the thickness of the back plate does not substantially increase the size. A large heat dissipation area can be secured. Further, by covering one surface in the thickness direction of the light guide plate with the back plate, light leakage to the back of the light guide plate can be prevented, and the back plate can be used for both a heat dissipation function and an optical function. In addition, since the substrate holder and the back plate are formed continuously and integrally, the substrate holder and the back plate can be handled as one component, leading to a reduction in the number of components.

  According to the configuration of the invention of claim 3, since the light leaking from the back surface of the light guide plate is reflected again by the reflection film formed on the back plate, the light leaks from the back surface of the light guide plate. Therefore, the utilization rate of light with respect to input power is increased. In addition, since the reflecting film is white, the surface of the reflecting film has diffuse reflectivity, so that glare is not generated, and the light is re-incident on the light guide plate without being distributed. The light can be emitted from the emission surface of the optical plate.

  According to the configuration of the invention of claim 4, since the substrate holder and the outer frame that surround the entire circumference of the peripheral surface of the light guide plate are used for heat dissipation of the semiconductor light emitting device, the outer frame is of the size of the portion that surrounds the light guide plate. A large heat dissipation area can be secured without substantial increase in size due to the increase in dimensions. Moreover, since the substrate holder and the light guide plate surround the entire peripheral surface of the light guide plate, light leakage from the peripheral surface of the light guide plate can be prevented, and the periphery of the light guide plate can be protected. Furthermore, since the light guide plate is surrounded by the substrate holder and the outer frame, the substrate holder and the outer frame can be used as a member for attaching a display panel or the like.

  According to the configuration of the invention of claim 5, a box body having a substrate holder and an outer frame surrounding the entire circumference of the peripheral surface of the light guide plate, and a back plate covering one surface in the thickness direction of the light guide plate is formed on the semiconductor light emitting device. Since it is used for heat dissipation, a large heat dissipation area can be ensured without substantial increase in size due to an increase in size due to the box surrounding the periphery of the light guide plate. In addition, since a portion other than the light exit surface of the light guide plate is surrounded by a metal box, unnecessary light leakage from the light guide plate can be prevented and the periphery of the light guide plate can be protected. Furthermore, since the light emitted from the light guide plate is extracted from the opening of the box, the box can be used as a member for attaching a display panel or the like.

  According to the structure of Claim 6, the lighting fixture for a display which show | plays the effect of the invention of Claims 1-5 mentioned above can be provided.

(Embodiment 1)
In the present embodiment, as shown in FIG. 1, an example in which a guide lamp is configured by disposing a display panel 40 made of a translucent material on which a guide sign is written facing the light emitting surface of the surface light source device A. Show. The surface light source device A includes a light emitting diode (semiconductor light emitting element) 11 as a light source and a light guide plate 20 that is used together with the light emitting diode 11 to perform surface light emission.

  The light emitting diode 11 is a surface mounting type, and is mounted on the mounting surface 12a of the strip-shaped substrate 12 using solder. The light emitting diodes 11 are arranged in a line at equal intervals along the longitudinal direction of the substrate 12.

  The substrate 12 is held by the substrate holder 13. The substrate holder 13 is formed of a metal material in a U-shaped cross section, and comes from a mounting piece 13a with which one surface that is opposite to the mounting surface 12a contacts in the thickness direction of the substrate 12, and from each side edge in the width direction of the mounting piece 13a. Each includes a front piece 13b and a rear piece 13c extending in a direction orthogonal to the mounting piece 13a. The substrate 12 is disposed between the front piece 13b and the rear piece 13c. Therefore, the heat from the light emitting diode 11 is conducted to the substrate holder 13.

  As shown in FIG. 2, the light guide plate 20 has one of the four peripheral surfaces facing the mounting surface 12 a of the substrate 12, and this one surface functions as an incident surface 20 a on which light from the light emitting diode 11 is incident. To do. Further, one surface in the thickness direction of the light guide plate 20 functions as an emission surface 20b that emits light. The other surface in the thickness direction of the light guide plate 20 includes a reflecting surface 20c that is inclined so as to decrease the distance from the exit surface 20b as the distance from the incident surface 20a increases, and is formed in a wedge shape as a whole. The light guide plate 20 is formed of a translucent material such as a transparent acrylic resin or polycarbonate resin.

  The substrate holder 13 is formed of a silver metal material having a high reflectivity, or plated or painted on the surface surrounding the substrate 12 so that the light from the light emitting diodes 11 efficiently enters the incident surface 20a of the light guide plate 20. As a result, a white reflective film is formed. That is, the substrate holder 13 has a function as a reflector as well as a function of holding the substrate 12. The reflectance of the surface surrounding the substrate 12 in the substrate holder 13 (the reflectance of the reflecting film when a reflecting film is provided) is 70% or more, preferably 90% or more.

  The light from the light emitting diode 11 is incident on the incident surface 20a of the light guide plate 20 and propagates through the light guide plate 20 by repeating total reflection between the output surface 20b and the reflection surface 20c, and is formed on the output surface 20b. The light that has reached the light diffusion portion (not shown) diffuses and passes through the light diffusion portion and is emitted from the emission surface 20b. The light diffusing portion is formed, for example, by forming a part of the emission surface 20b as a rough surface or providing a minute spherical surface or the like as a part of the emission surface 20b. The light diffusing section is provided over the entire surface of the emission surface 20b, and light is emitted from the entire surface of the emission surface 20b. Therefore, the light emission surface 20b of the light guide plate 20 can emit surface light.

  The light emitted from the emission surface 20b is incident on the optical sheet 21 disposed to face the emission surface 20b. The optical sheet 21 is formed with a plurality of rows of prisms 21 a having a substantially triangular cross section whose tip is in contact with the light exit surface 20 b of the light guide plate 20. Each prism 21 a is formed so that the ridge line direction is parallel to the incident surface 20 a of the light guide plate 20.

  The light that has entered one of the prisms 21a is totally reflected by the wall surfaces of the other adjacent prisms 21a and is emitted from the surface of the optical sheet 21 (the surface opposite to the surface on which the prisms 21a are formed). The traveling direction of the light emitted from the emission surface 20 b of the light guide plate 20 is brought closer to the direction perpendicular to the emission surface 20 b by the optical sheet 21. That is, the optical sheet 21 performs light distribution that increases the luminance in the direction perpendicular to the emission surface 20b. In addition, by changing the cross-sectional shape (substantially triangular shape) of the prism 21a, light distribution in an arbitrary direction can be performed on a surface perpendicular to the incident surface 20a and the emitting surface 20b.

  Note that the prism 21 a in the optical sheet 21 can be formed along a direction perpendicular to the incident surface 20 a of the light guide plate 20. In this case, by changing the shape of the cross section of the prism 21a, light distribution in an arbitrary direction can be performed on a surface parallel to the incident surface 20a and perpendicular to the output surface 20b.

  A display panel 40 facing the optical sheet 21 is disposed on the opposite side of the light guide plate 20 across the optical sheet 21, and light distributed by the optical sheet 21 enters the display panel 40.

  The display panel 40 is screen-printed on at least one surface of the back surface (lower surface in the drawing) that is the surface facing the optical sheet 21 or the front surface (upper surface in the drawing) that is far from the optical sheet 21. A pattern is formed by a cutting sheet or the like. The display panel 40 is made of acrylic resin, polycarbonate resin, or glass transparently. However, the display panel 40 can also be formed of a diffuse transmission material.

  The design (guide sign) of the display panel 40 shown in FIG. 3 is an example of a design used for an escape exit guide light, and the design is formed in two colors of white and green (filled area). 4 is an example of a symbol used for a passage guide light, and the symbol is formed in two colors of white and green (filled area). When the light distributed by the optical sheet 21 passes through the display panel 40, the design of the display panel 40 can be visually recognized, and guidance can be performed.

  By the way, in the surface light source device A shown in FIG. 1, as described above, since the surface-mounted type is used for the light emitting diode 11, the heat of the light emitting diode 11 is transmitted to the substrate 12. Moreover, since the back surface of the mounting surface 12a contacts the surface of the mounting piece 13a of the substrate holder 13, the substrate holder 13 is thermally coupled to the substrate 12, and the heat of the light emitting diode 11 transmitted to the substrate 12 is transferred to the substrate 12. It is transmitted to the holder 13. The heat of the light emitting diode 11 transmitted to the substrate holder 13 is radiated from the surface of the substrate holder 13.

  In the present embodiment, a back plate 30 made of a metal plate is disposed facing the reflecting surface 20c of the light guide plate 20, and the thickness of the back piece 13c and the back plate 30 of the substrate holder 13 is shown in FIG. The substrate holder 13 is thermally coupled to the back plate 30 by overlapping one end (front surface) in the direction. Therefore, the heat of the light emitting diode 11 transmitted to the substrate holder 13 is also transmitted to the back plate 30 and radiated from the back plate 30. That is, the rear piece 13 c functions as a heat transfer piece that transfers heat to the back plate 30.

  That is, the heat of the light emitting diode 11 is radiated from both the substrate holder 13 and the back plate 30. Here, the light guide plate 20 that performs surface light emission on the emission surface 20b is a larger component than the substrate 12 and the light emitting diode 11, and the back plate 30 faces the reflection surface 20c of the light guide plate 20, and thus reflects in a space-saving manner. A large heat radiation area corresponding to the surface 20c can be secured.

  Therefore, the junction temperature of the light emitting diode 11 can be reduced without reducing the power supplied to the light emitting diode 11 and without using a device for water cooling or air cooling. Since it is not necessary to reduce the power supplied to the light emitting diode 11, a necessary light flux can be secured without increasing the number of the light emitting diodes 11 used, and since the cooling device is not used, the surface light source device A can be used in various environments. The surface light source device A can be prevented from being enlarged.

  Further, since the junction temperature can be reduced, the light emitting diode 11 can be used so that the junction temperature does not exceed the maximum junction temperature, and the life of the light emitting diode 11 can be extended.

  By the way, the back plate 30 is formed of a silver metal material having a high reflectance, and reflects the light leaking from the reflection surface 20 c of the light guide plate 20. The light leaking from the reflecting surface 20c of the light guide plate 20 is returned to the light guide plate 20 by being reflected by the back plate 30 and reused. The reflectance of the back plate 30 is, for example, 70% or more, preferably 90% or more.

  As described above, since the light leaking from the reflecting surface 20c is reflected using the back plate 30 and returned to the light guide plate 20, the member that returns the light leaking from the reflecting surface 20c to the light guide plate 20 (reflection in the conventional example) There is no need to provide a separate sheet), reducing the number of parts and reducing costs.

  Further, a white reflective film can be formed on the surface of the back plate 30 on the light guide plate 20 side by plating or painting. In this case, an effect of increasing the reflectance of the back plate 30 by the reflective film can be expected, and white light can be emitted from the light guide plate 20, and the white coloration in the display panel 40 becomes unnecessary, and the display panel 40 The printing process can be reduced.

  Incidentally, when the electronic component 14 other than the light emitting diode 11 is mounted on the substrate 12, the electronic component 14 is mounted on the back surface side of the mounting surface 12a of the substrate 12, as shown in FIG. Alternatively, as shown in FIG. 7, the electronic component 14 can be mounted on the mounting surface 12 a side of the substrate 12. As the electronic component 14, for example, there is a constant voltage diode (zener diode) connected in parallel to each light emitting diode 11 so that a surge voltage is not applied to the light emitting diode 11.

  When the electronic component 14 is mounted on the back surface side of the mounting surface 12a of the substrate 12, for example, a double-side mounting type glass epoxy substrate (FR4) can be used for the substrate 12. Further, when the electronic component 14 is mounted on the back surface side of the mounting surface 12a of the substrate 12, the substrate 12 is configured such that the heat conductive sheet 15 is sandwiched between the substrate 12 and the substrate holder 13 as shown in FIG. The substrate 12 is attached to the holder 13, and the substrate 12 and the substrate holder 13 are thermally coupled by the heat conductive sheet 15.

  When the substrate 12 is warped, the contact area between the substrate 12 and the mounting piece 13a of the substrate holder 13 is reduced. However, by using the heat conductive sheet 15, even if the substrate 12 is warped, the contact between the substrate 12 and the substrate holder 13 is reduced. The contact area is not reduced, and a decrease in heat conduction efficiency is suppressed.

  Similarly, the heat conductive sheet 16 can be sandwiched between the back piece 13 c of the substrate holder 13 and the back plate 30, and the substrate holder 13 and the back plate 30 can be thermally coupled by the heat conductive sheet 16. Even when the electronic component 14 is not mounted on the back surface side of the mounting surface 12 a of the substrate 12, the heat conductive sheet 15 can be sandwiched between the substrate 12 and the substrate holder 13.

  When the light emitting diode 11 or the light emitting diode 11 and the electronic component 14 are mounted on the mounting surface 12a side of the substrate 12, as shown in FIG. 7, a metal heat transfer plate 17 is mounted on the back surface of the mounting surface 12a. 12 can be used. Since the heat transfer plate 17 is made of metal, warpage of the substrate 12 is suppressed by the heat transfer plate 17, and a decrease in heat conduction efficiency between the substrate 12 and the substrate holder 13 can be suppressed.

  In the configuration example described above, the prism 21a of the optical sheet 21 is formed on the light emitting surface 20b side of the light guide plate 20, but the prism 21a can be formed on the display panel 40 side.

  In addition, a light diffusion sheet may be disposed between the optical sheet 21 and the light guide plate 20, and the light emitted from the emission surface 20 b of the light guide plate 20 may be further diffused by the light diffusion sheet.

  Further, a light diffusing sheet is disposed between the light guide plate 20 and the back plate 30, and two optical sheets 21 are disposed on both the emission surface 20 b side and the reflection surface 20 c side of the light guide plate 20. be able to.

  In the present embodiment, an example in which the display panel 40 is illuminated has been described. However, a liquid crystal panel may be disposed instead of the display panel 40, and the surface light source device A may be used as a backlight of the liquid crystal panel.

(Embodiment 2)
In the present embodiment, as shown in FIG. 8, a configuration example in which the substrate holder 13 and the back plate 30 are continuously formed integrally is shown. The substrate holder 13 and the back plate 30 are integrally formed in a form in which the rear piece 13c of the substrate holder 13 and the back plate 30 are connected. The substrate holder 13 and the back plate 30 can be formed, for example, by bending a metal plate. In the present embodiment, since the substrate holder 13 and the back plate 30 are formed continuously and integrally, the number of components can be reduced as compared with the first embodiment.

  By the way, as in the first embodiment, the light guide plate 20 is formed in a wedge shape as a whole, and the back plate 30 is disposed substantially parallel to the emission surface 20b of the light guide plate 20, so that the reflection surface 20c is the incident surface. As the distance from 20a increases, the distance from the back plate 30 increases, and a gap is formed between the reflective surface 20c and the back plate 30. Therefore, the reflection angle by the back plate 30 of the light leaked from the light guide plate 20 to the back may vary.

  Therefore, as shown in FIG. 9, the connecting portion between the back plate 30 and the substrate holder 13 is bent, and the back plate 30 is disposed over the entire surface in parallel with the reflecting surface 20 c of the light guide plate 20. The formation of gaps may be prevented. With this configuration, it is possible to prevent variations in the reflection angle due to the back plate 30.

  In the configuration of the present embodiment, as in the first embodiment, a white reflective film 30c may be formed on the inner surface of the substrate holder 13 and the surface of the back plate 30 by plating or painting (see FIG. 10). Other configurations and functions are the same as those of the first embodiment.

(Embodiment 3)
As shown in FIG. 11, the surface light source device A exemplified in this embodiment includes an outer frame 31 that is formed integrally with the substrate holder 13 instead of the back plate 30.

  The outer frame 31 is formed in a U shape so as to surround a peripheral surface of the light guide plate 20 excluding the incident surface 20a. Therefore, the outer frame 31 surrounds the peripheral surface of the light guide plate 20 along with the substrate holder 13 over the entire circumference.

  The substrate holder 13 and the outer frame 31 can be formed, for example, by bending a metal plate. The substrate holder 13 and the outer frame 31 are formed of a silver metal material having a high reflectance, or a reflection film is formed on the inner surface by plating or painting. The reflectivity of the substrate holder 13 and the outer frame 31 (a reflective film when a reflective film is formed) is, for example, 70% or more, preferably 90% or more.

  As described above, in the present embodiment, since the substrate holder 13 and the outer frame 31 are formed continuously and integrally, the heat of the light emitting diodes 11 transmitted to the substrate holder 13 is also generated in the outer frame 31 in addition to the substrate holder 13. Heat is dissipated.

  As described above, the light guide plate 20 is a larger component than the substrate 12 and the light emitting diode 11, and the outer frame 31 surrounds the entire circumference of the light guide plate 20 together with the substrate holder 13. A large heat radiation area corresponding to the peripheral surface of the optical plate 20 can be secured. Further, by forming the substrate holder 13 and the outer frame 31 continuously and integrally, a large heat radiation area can be secured without increasing the number of components.

  By the way, in this embodiment, on the reflective surface 20c side of the light guide plate 20, a reflective sheet 22 that faces the reflective surface 20c and reflects light leaking from the reflective surface 20c is disposed. That is, the reflection sheet 22 has a function of reflecting light leaking from the reflection surface 20 c of the light guide plate 20 in the back plate 30. The reflection sheet 22 is formed of a material having a high reflectance, or a white reflection film is formed by plating or painting. The reflectance of the reflection sheet 22 is 70% or more, preferably 90% or more.

  Further, since the light guide plate 20 and the display panel 40 can be fixed to the outer frame 31, the engaging portion that engages with the light guide plate 20 and the display panel 40, and the light guide plate 20 and the display panel 40 are fixed. A screw hole or the like into which the fixing screw is screwed can be provided in the outer frame 31. The engaging portion can be formed by, for example, a notch. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 4)
As shown in FIG. 12, the surface light source device A exemplified in the present embodiment includes a metal box 32 that houses the light guide plate 20 ′. In the present embodiment, a light guide plate 20 ′ having a plurality of prism grooves 20d ′ formed on the reflection surface 20c ′ is used.

  As shown in FIG. 13, the light guide plate 20 ′ is inclined so that the reflection surface 20 c ′ is substantially perpendicular to the incident surface 20 a ′, and the exit surface 20 b ′ is closer to the reflection surface 20 c ′ as the distance from the incident surface 20 a ′ increases.

  Plural prism grooves 20d 'are formed along the incident surface 20a' over the entire surface of the incident surface 20a '. A part of the light propagating in the light guide plate 20 ′ is reflected by the wall surface of the prism groove 20 d ′ and is emitted from the emission surface 20 b ′ while propagating.

  In the present embodiment, a diffusion film 23 is disposed between the display panel 40 and the light guide plate 20 ′ in order to diffuse the light emitted from the light guide plate 20 ′ and make the surface brightness of the display panel 40 uniform. The In addition, a lens sheet 24 is disposed between the diffusion film 23 and the display panel 40 in order to distribute the light diffused by the diffusion film 23.

  In Embodiments 1 to 3, a diffusion film 23 and a lens sheet 24 may be used instead of the optical sheet 21 (see FIG. 1). Further, a light guide plate 20 ′ may be used instead of the light guide plate 20.

  The box 32 in which the light guide plate 20 ′ is accommodated faces the outer frame 31 ′ that surrounds the entire circumference of the light guide plate 20 ′ together with the substrate holder 13 ′, and the reflection surface 20c ′ of the light guide plate 20 ′. And a back plate 30 'arranged continuously. That is, the back plate 30 ′ of the box body 32 has the same function as the back plate 30 (see FIG. 1) described in the first embodiment, and the outer frame 31 ′ of the box body 32 is the outer frame described in the third embodiment. 31 (see FIG. 11). In other words, the box body 32 is formed by continuously and integrally forming the substrate holder 13, the frame body 31, and the back plate 30.

  In the present embodiment, the box body 32 has both the function of the back plate 30 and the function of the outer frame 31, and thus a larger heat radiation area compared to the above-described embodiments without increasing the number of parts. Can be secured.

  Further, as in the third embodiment, an engaging portion and a screw hole for fixing the light guide plate 20 ′, the display panel 40, and the like can be formed on the peripheral wall of the box body 32. Other configurations are the same as those of the first embodiment.

(Embodiment 5)
In the present embodiment, an example in which a guide light (display lighting fixture) is configured using the surface light source device A of each of the embodiments described above will be described. Guide lights are for the purpose of recognizing the existence of evacuation exits in the event of an emergency such as a power outage or disaster. ing. In this embodiment, the example installed in ceilings, such as a building, is shown. However, the present invention is not limited to this, and can be installed on a passage, a floor of a room, or a wall.

  As shown in FIG. 14, the guide light includes a surface light source device A and an instrument body 50 attached to the ceiling. The front surface of the instrument body 50 is opened, and the surface light source device A is attached to the front surface of the instrument body 50.

  A lighting circuit block 51 connected to a commercial power source AC (see FIG. 15) and a secondary battery 52 are accommodated in the appliance main body 50. The lighting circuit block 51 and the substrate 12 on which the light emitting diode 11 is mounted are connected via connectors 54a and 54b.

  As shown in FIG. 15, the lighting circuit block 51 includes a charging circuit 51a that charges the secondary battery 52 with a commercial power source AC, and a regular lighting circuit that lights the light emitting diode 11 with power supplied from the commercial power source AC when there is no power failure. 51b and an emergency lighting circuit 51c for lighting the light emitting diode 11 with the power supplied from the secondary battery 52 when the power supply from the commercial power supply AC is stopped, such as during a power failure. The plurality of light emitting diodes 11 are connected in series, and are connected to the regular lighting circuit 51b and the emergency lighting circuit 51c.

  By the way, when the surface light source device A shown in the first, second, and fourth embodiments is attached to the instrument main body 50, the back plate 30 made of metal, which is a noncombustible material, or the bottom 31 ′ of the box body 32 is connected to the lighting circuit block 51 and Since it is located between the secondary battery 52 and the light guide plate 20 and the display panel 40, even if the lighting circuit block 51 or the secondary battery 52 may ignite, the bottom of the back plate 30 or the box 32. 30 'prevents the light guide plate 20 and the display panel 40 from being burned, and ensures safety.

  In the above-described configuration example, the example in which the surface light source device A is attached to the box-shaped instrument body 50 whose one end is open is shown. However, as illustrated in FIG. 53, the surface light source device A can be attached to the lower end of the column 53, and the surface light source device A can be suspended from the ceiling. In the illustrated example, a flange portion 55 is provided on the lower surface of the instrument main body 50, and when the instrument main body 50 is embedded in the ceiling, the flange portion 55 is abutted against the ceiling surface.

  In the present embodiment, the guide light is exemplified as the display lighting device, but the present invention is not limited to this, and a car tail lamp, an advertisement light, or the like may be used.

  In each of the above-described embodiments, the surface-mounted light emitting diode 11 is exemplified as the semiconductor light emitting element, but a laser diode can also be used as the semiconductor light emitting element.

  Moreover, in each embodiment mentioned above, although the example which arranged the some light emitting diode 11 in 1 row was shown, the some light emitting diode 11 can also be arranged in 2 or more rows.

1 is an exploded perspective view showing Embodiment 1. FIG. It is principal part sectional drawing same as the above. It is a front view which shows an example of the display panel used for the same as the above. It is a front view which shows the other example of the display panel used for the same as the above. An example of the board | substrate used for the same is shown, (a) is a top view, (b) is a side view, (c) is a bottom view. It is principal part sectional drawing which shows the other structural example same as the above. The other example of the board | substrate used for the same is shown, (a) is a top view, (b) is a side view, (c) is a bottom view. FIG. 6 is a cross-sectional view of a main part showing Embodiment 2. It is principal part sectional drawing which shows the other example same as the above. It is principal part sectional drawing of the member used for the same as the above. FIG. 6 is an exploded perspective view showing a third embodiment. FIG. 6 is an exploded perspective view showing a fourth embodiment. It is principal part sectional drawing same as the above. FIG. 10 is an exploded perspective view showing a fifth embodiment. It is a circuit diagram same as the above. It is a perspective view which shows the other example same as the above.

Explanation of symbols

11 Light Emitting Diode (Semiconductor Light Emitting Element)
12 Substrate 13 Substrate holder 13 'Substrate holder 13c Rear piece (heat transfer piece)
DESCRIPTION OF SYMBOLS 20 Light-guide plate 20a Incident surface 20b Outgoing surface 30 Back plate 30 'Back plate 31 Outer frame 31' Outer frame 32 Box 50 Instrument body A Surface light source device

Claims (6)

  A plurality of semiconductor light-emitting elements mounted on the substrate, a substrate holder that holds the substrate and is thermally coupled to the substrate, and at least part of the peripheral surface is an incident surface on which light from the semiconductor light-emitting element is incident, and is one surface in the thickness direction And a back plate that is a metal plate that covers the other surface in the thickness direction of the light guide plate, and the substrate holder overlaps a part of the back plate on one surface in the thickness direction of the back plate. A surface light source device comprising a heat transfer piece thermally coupled to a back plate.   A plurality of semiconductor light-emitting elements mounted on the substrate, a substrate holder that holds the substrate and is thermally coupled to the substrate, and at least part of the peripheral surface is an incident surface on which light from the semiconductor light-emitting element is incident, and is one surface in the thickness direction A surface light source device comprising: a light guide plate having an emission surface; and a back plate that is a metal plate that covers the other surface in the thickness direction of the light guide plate, and the back plate is formed integrally with the substrate holder. .   The surface light source device according to claim 1, wherein a white reflective film is formed on a surface of the back plate that faces the light guide plate.   A plurality of semiconductor light emitting devices mounted on a substrate, a substrate holder that holds the substrate and is thermally coupled to the substrate, and at least part of the peripheral surface is an incident surface on which light from the semiconductor light emitting device is incident, and is one surface in the thickness direction And an outer frame made of metal that surrounds the entire circumference of the light guide plate together with the substrate holder, and the outer frame is formed integrally with the outer frame. A characteristic surface light source device.   A plurality of semiconductor light emitting devices mounted on a substrate, a substrate holder that holds the substrate and is thermally coupled to the substrate, and at least part of the peripheral surface is an incident surface on which light from the semiconductor light emitting device is incident, and is one surface in the thickness direction And a back plate that covers the entire circumference of the light guide plate together with the substrate holder, and a back plate that covers the other surface in the thickness direction of the light guide plate and closes one surface of the outer frame. A surface light source device, characterized in that the box is formed integrally with the substrate holder.   A display lighting fixture comprising: the surface light source device according to any one of claims 1 to 5; and a fixture main body to which the surface light source device is attached.

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