JP6025163B2 - Light emitting device - Google Patents

Description

  The present invention relates to a light-emitting device using a light-emitting element such as an LED (Light Emitting Diode), and more specifically, reflects light emitted from the light-emitting element by a reflecting member so as to face the light-emitting element in the back direction (light emission). The present invention relates to an improvement of a reflective light emitting device that emits light in a direction opposite to the direction.

  Conventionally, as a light emitting device, a reflecting member (reflector) is disposed so as to face the light emitting surface of the LED element, light (emitted light) emitted from the LED element is reflected by the reflector, and the reflected light (reflected light) is LED. A so-called reflective type that emits light toward the back of the element has been developed (Patent Document 1).

  Since this reflection type light emitting device can emit light emitted from the LED element to the outside with high efficiency, it is particularly useful in a light emitting device that requires high luminance.

Japanese Patent Laid-Open No. 10-335706

  Here, although the light emitting device is used for various things, since the LED element generates less heat than an incandescent lamp or the like, it is used as a lighting part of a traffic signal lamp in a situation where it is exposed to snow, for example. In such a case, the snow attached to the protective cover provided on the forefront of the lighting part is difficult to melt, and the attached snow may reduce the visibility of the light emission state of the lighting part.

  This is a more significant problem when a reflective light-emitting device capable of reducing the number of LED elements is used in a lighting part of a traffic signal light because of its high efficiency.

  The above problem can occur not only when the light-emitting device is used for traffic signal lights, but also when it is used for street lights or lighting fixtures where there is a risk of snowfall or icing.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light-emitting device capable of removing the attached snow and ice even under the situation where snow and ice are attached.

  In the light emitting device according to the present invention, the reflection member facing the light emitting element of the circuit board provided in contact with the cover is supported by the cover by the support member, so that the circuit board is surrounded by the support member and emitted from the circuit board. It forms a narrow space where convection heat can be prevented to prevent heat diffusion, makes it easy to transfer convection heat to the cover, raises the temperature of the cover, and even if snow or ice adheres to the cover, these adhering snow And ice is removed by melting it with heat.

  That is, a light emitting device according to the present invention includes a circuit board provided with a light-transmitting cover, a plurality of light emitting elements mounted on one surface side, and a surface opposite to the one surface in contact with the cover. A light-emitting device that is disposed on the opposite side of the circuit board and reflects the light from the light-emitting element, and further includes a support member that supports the reflective member on the cover. Features.

  According to the light emitting device according to the present invention, it is possible to eliminate the adhering snow and ice even in a situation where the snow and ice adhere.

It is a schematic diagram which shows the traffic signal lamp provided with the lighting part as one Embodiment of the light-emitting device of this invention. It is a fragmentary sectional view which shows the structure of a lighting part. It is the figure which showed typically the state by which the several LED element etc. were distributed and mounted on the circuit board. It is a figure which shows the cross section of the principal part cut | disconnected by the surface (surface along the AA line of FIG. 2) orthogonal to the direction where the circuit board extended. It is a block diagram which shows the circuit by an LED element and a control circuit. It is a figure explaining the function of a control circuit, (a) shows the state which switched between the groups of LED element to the serial connection, (b) is the connection which combined the serial connection and parallel connection between the groups of LED element (C) shows a state where all LED element groups are switched to parallel connection. It is a perspective view which shows a reflector. FIG. 5 is a cross-sectional view of a main part corresponding to FIG.

  Embodiments of a light emitting device according to the present invention will be described below with reference to the drawings.

  The present embodiment is an example in which the light emitting device according to the present invention is applied to the lighting unit 100 corresponding to each color (red, yellow, green) of the traffic light 200 shown in FIG.

  In addition, although the traffic signal lamp 200 shown in FIG. 1 is the thing in which the three lighting parts 100 were arranged vertically, it cannot be overemphasized that it may be arranged horizontally.

  However, as a countermeasure against snow damage in a snowy cold region, the vertical type in which the lighting parts 100 are arranged vertically is advantageous in that it has less snowfall.

  As shown in FIG. 2, each lighting unit 100 includes a protective cover 30 formed in a substantially disc shape, a unit case 40 formed in a bottomed cylindrical shape, and an exterior of the protective cover 30 and the unit case 40. A housing is formed by an annular waterproof rubber packing 50 that holds the peripheral portions in an overlapped state and prevents water from entering the internal space surrounded by the protective cover 30 and the unit case 40.

  The protective cover 30 is made of, for example, polycarbonate, and has translucency that transmits light emitted from the LED element 14 (see FIG. 3 and the like) described later.

  The unit case 40 is made of, for example, ABS resin, and is provided with a connector 70 to which an electric wire for receiving power supply such as a commercial power source from an external control device is connected.

  Inside the housing are a spiral circuit board 11 (printed wiring board, etc.), a reflector 20 (reflecting member) that reflects light, and a back surface side of the reflector 20 (a concave surface 21 that is a reflecting surface (see FIG. 4)). And the heat insulating material 60 arranged on the opposite side).

  On one surface 11m side of the spiral circuit board 11, as shown in FIG. 3, along the extending direction, for example, 31 LED elements 14 (light emitting elements), for example, four control circuits 15 and A set of terminals 16 are distributed and mounted. The LED element 14 in the present embodiment is an LED chip packaged.

  As shown in FIGS. 3 and 4, the circuit board 11 is provided so that the opposite surface 11 n on which the LED element 14 or the like is not mounted is in contact with the back surface 32 (the surface facing the inside of the housing) of the protective cover 30. For example, it is affixed on the protective cover 30 with an adhesive, a double-sided tape, or the like.

  Accordingly, the light emitting surface 14a from which the light L is emitted from the LED element 14 faces the interior of the housing, not the direction of the front surface 31 of the protective cover 30, and the protective cover 30 is connected to the back surface 14b ( The light-emitting surface 14a is disposed on the opposite side (back surface) side.

  The terminal 16 provided on the circuit board 11 is connected to a connector 70 provided on the unit case 40 by an electric wire or the like, and receives power supply such as commercial power from an external control device.

  A large number of LED elements 14 mounted on the circuit board 11 are divided into a plurality of groups and connected, and the control circuit 15 is a commercial power source for causing the LED elements 14 to emit light (drive). When applying the rectified voltage obtained by rectifying the alternating current to each group, the connection form between a plurality of groups is controlled to appropriately switch between parallel connection and series connection according to the magnitude of the rectified voltage ( For example, LED driving circuit disclosed in Japanese Patent Application Laid-Open No. 2011-159902.

  That is, four control circuits 15 in this embodiment are mounted on the circuit board 11. On the other hand, the 31 LED elements 14 mounted on the circuit board 11 are grouped into four groups of eight, eight, eight, and seven in order from the side close to the terminal 16 (for example, group A and group B). , Group C and group D).

  Of the four control circuits 15, three control circuits 15 are arranged one by one between the groups of the LED elements 14, and the remaining one control circuit 15 is the first group of the terminal 16 and the LED elements 14. It is arranged between.

  As shown in FIG. 5, the plurality of LED elements 14 belonging to each group are all connected in series within the group. Further, the connections between the groups are connected so that the series connection and the parallel connection can be switched, and each control circuit 15 can connect these two connection forms according to the magnitude of the rectified voltage input to the terminal 16. One of the connection forms is selected, and control to switch to the selected connection form is performed.

  Specifically, since the commercial power supplied to the terminal 16 is an AC voltage, the AC voltage is full-wave rectified to drive the LED element 14, but the DC voltage (rectified) obtained by the full-wave rectification is used. The magnitude of (voltage) changes in time series.

According to the value of the rectified voltage input to the terminal 16, the control circuit 15 selects one of the following (1) to (3) as a connection form between the groups of seven or eight LED elements 14. Control it. That is,
(1) During a period in which the input rectified voltage is larger than a preset first threshold value, all groups A, B, C, and D are connected in series as shown in FIG. Control
(2) During a period in which the input rectified voltage is equal to or lower than a preset first threshold value and equal to or higher than a second threshold value (a value less than the first threshold value), as shown in FIG. B is connected in series, groups C and D are connected in series, and two sets of series connections are connected in parallel.
(3) During the period when the input rectified voltage is less than the preset second threshold, control is performed so that all the groups A, B, C, and D are connected in parallel as shown in FIG. Do

  In addition, the symbol of the circled arrow in FIG. 6 shows a constant current source.

  As described above, by switching the connection form between the groups of the plurality of LED elements 14 according to the magnitude of the input rectified voltage, the LED element 14 cannot emit light when the rectified voltage is connected in series, for example. Even during a period of a voltage lower than the threshold value, the LED element 14 can emit light stably by connecting a part or all of them in parallel.

  As shown in FIG. 4, the reflector 20 is provided on the side facing the light emitting surface 14 a of the LED element 14, and has a translucent transparent resin layer 87 that transmits light L emitted from the LED element 14. The reflective film 26 is formed on the convex surface 82 on the side far from the LED element 14.

  The transparent resin layer 87 of the reflector 20 is formed of a transmissive material such as polycarbonate, for example, and as shown in FIG. 7, the surface 81 facing the LED element 14 has a partially recessed recess 83, 84 and 85 (only the recessed part 83 is described in FIG. 4) is formed.

  As shown in FIG. 4, each of the recesses 83 is formed corresponding to a portion of the circuit board 11 where the LED element 14 is mounted.

  The concave portions 84 and 85 are the same as the concave portion 83, but the concave portion 85 is formed corresponding to a portion of the circuit board 11 in which the terminal 16, the control circuit 15, and the LED element 14 are continuously arranged. The recess 84 is formed in the circuit board 11 so as to correspond to a portion of the control circuit 15 and the two LED elements 14 and 14 arranged so as to sandwich the control circuit 15.

  The recess 83 is formed corresponding to only the remaining LED elements 14 that are not surrounded by the recesses 84 and 85 in the circuit board 11.

  Although the circuit board 11 and the back surface 32 of the protective cover 30 are in direct contact with each other, the concave portions 83, 84, 85 of the reflector 20 and the circuit board 11 are not in direct contact with each other, but are arranged via an air layer. It has become.

  Of the transparent resin layer 87 of the reflector 20, the portions other than the recesses 83, 84, 85 are connected to the recesses 83, 84, 85 and are formed in a contour shape along the back surface 32 of the protection cover 30. 30 is a support portion 86 (support member) that supports the reflector 20 on the protective cover 30 in contact with the back surface 32 of the cover 30 (see FIG. 4). The support portion 86 may be one that supports the reflector 20 on the protective cover 30 by welding, for example, or an adhesive or the like is applied between the reflector 20 and the support portion 86 so that the reflector 20 is attached to the protective cover 30. You may support.

  In the lighting part 100 of the present embodiment, the support part 86 is formed as a part of the reflector 20, but the support part 86 is formed separately from the reflector 20, and is shown in FIG. As described above, the part other than the recesses 83, 84, 85 of the reflector 20 is interposed between the surface 81 facing the protective cover 30 and the back surface 32 of the protective cover 30 to support the reflector 20 on the protective cover 30. Also good.

  Also in this case, the support part 86 may support the reflector 20 on the protective cover 30 by welding, for example, or between the reflector 20 and the support part 86 and between the protective cover 30 and the support part 86. An adhesive or the like may be applied to support the reflector 20 on the protective cover 30.

  Further, in the case of the support portion 86 having the configuration shown in FIG. 8, it is preferable that the support portion 86 is formed in an annular shape over the entire outer periphery of each of the concave portions 83, 84, 85. As a result, the support portion 86 can be completely surrounded by the protective cover 30 and the reflector 20 around the LED element 14.

  However, the support portion 86 is not formed in such a ring shape, and may be formed scattered in portions other than the concave portions 83, 84, 85 of the reflector 20.

  In the lighting part 100 of the present embodiment, the support part 86 formed around the recess 83 is a part where the LED element 14 is mounted on the circuit board 11 by the protective cover 30 and the transparent resin layer 87 of the reflector 20. Is surrounded by a narrow space P that is closed.

  The support portions 86 formed around the recesses 84 and 85 are the same as the support portions 86 formed around the recesses 83, respectively. However, the support portions 86, the protective cover 30 and the support portions 86 formed around the recesses 85, respectively. The transparent resin layer 87 of the reflector 20 integrally surrounds a portion of the circuit board 11 where the terminals 16, the control circuit 15, and the LED elements 14 are continuously arranged.

  The support portion 86, the protective cover 30, and the transparent resin layer 87 of the reflector 20 formed around the recess 84 are formed on the circuit board 11 with the control circuit 15 and the two LED elements 14 and 14 arranged on both sides of the control circuit 15. The part of is integrally enclosed.

  The support portion 86, the protective cover 30, and the transparent resin layer 87 of the reflector 20 formed around the recess 83 are portions of the circuit board 11 that are only the remaining LED elements 14 that are not surrounded by the recesses 84 and 85. Are enclosed individually.

  The reflective film 26 is formed by depositing or plating a metal film on the convex surface 82 of the transparent resin layer 87, but is not limited to this form.

  Of the convex surface 82 of the transparent resin layer 87 on which the reflective film 26 is formed, the portion immediately below the light emitting surface 14a of the LED element 14 is formed to protrude in a substantially conical shape toward the light emitting surface 14a.

  The surfaces 28 and 29 of the reflective film 26 facing the transparent resin layer 87 cause the light L incident on the transparent resin layer 87 from the LED element 14 in the direction of the protective cover 30 (the direction facing the back surface 14b of the LED element 14). It is a reflective surface that reflects.

  The reflecting surface 28 is formed by a substantially parabolic surface having a light emitting point 14c which is the center of the light emitting surface 14a as a focal point. When the outgoing light L emitted from the light emitting surface 14a is reflected, the reflected light L is reflected. It is made to become substantially parallel light.

  On the other hand, the reflective surface 29 formed along the surface of the transparent resin layer 87 that protrudes in a substantially conical shape toward the light emitting surface 14a, emits the emitted light L emitted substantially vertically downward from the light emitting surface 14a. When reflected, the reflected light L is formed so as not to return to the LED element 14 as it is.

  In other words, when the reflected light L returns to the LED element 14 as it is, the reflected light L is shielded by the LED element 14 itself, but when a portion protruding in a substantially conical shape is formed as in this embodiment. Since the light L reflected by the reflecting surface 29 that is the inclined surface does not return to the LED element 14 as it is, the light shielding by the LED element 14 itself can be avoided.

  The light L reflected by the reflecting surfaces 28 and 29 of the reflector 20 and directed toward the protective cover 30 is transmitted through the protective cover 30 and emitted to the outside of the lighting unit 100, and can be viewed by an external viewer or the like. .

  In addition, the area of the area | region which the light L reflected by the reflector 20 of the protective cover 30 permeate | transmits is set to S1.

  Here, as shown in FIG. 4, the protective cover 30 is formed so as to be surrounded by the protective cover 30 and the concave portion 83 of the reflector 20 with respect to the area S1 of the region through which the light L from the reflecting surfaces 28 and 29 is transmitted. When the area of the surface where the protective cover 30 faces the space P is S2, the reflector 20 is formed such that the area S2 is smaller than the area S1 (S2 <S1).

  According to the lighting unit 100 configured as described above, the convection range of the heat generated from the LED element 14 is the inner side formed by partitioning the protective cover 30 and the recesses 83, 84, 85 of the reflector 20. Only in a narrow space P.

  And the heat in this narrow space P is more than the heat in the case of being discharged into a wide space (in particular, a substantially open space that is not partitioned by the concave portions 83, 84, 85, etc. of the reflector 20). Difficult to diffuse and easily transmitted to the protective cover 30 facing the space.

  This is because heat is conducted from the circuit board 11 serving as a heat generation source to the protective cover 30, and convection heat is transferred to the space P and convection heat is transferred to the protective cover 30. Further, the heat of the protective cover 30 is radiated to the outside by heat transfer by convection and heat radiation.

  That is, since this heat dissipation occurs on the surface where the protective cover 30 faces the space P, the larger the area S2, the easier the heat dissipation, so the temperature of the outer edge of the protective cover 30 decreases. On the other hand, the temperature of the protective cover 30 increases as the area S2 decreases.

  As a result, the heat generated from the LED element 14 can increase the temperature of at least the portion of the protective cover 30 facing the narrow space P as compared with the case where the support portion 86 is not provided.

  Therefore, when the traffic signal lamp 200 is used in a situation where it is exposed to snowfall or the like, even if snow or ice adheres to the protective cover 30, the protective cover 30 is still warmed. Therefore, it is possible to prevent the visibility of the emitted light L that has melted and flowed downward and transmitted through the protective cover 30 from being obstructed by snow or ice.

  Moreover, since the circuit board 11 is provided in contact with the protective cover 30 in the lighting unit 100 of the present embodiment, the heat generated by the LED element 14 is applied to the protective cover 30 via the circuit board 11 depending on the type of heat conduction. The temperature of the protective cover 30 can be further increased.

  Further, the lighting unit 100 according to the present embodiment can further warm the protective cover 30 by heat conduction from the control circuit 15 by providing the control circuit 15 in some places on the circuit board 11, and this control. Since the circuit 15 is also surrounded by the reflector 20, the support portion 86, and the protective cover 30 and is confined in the narrow space P, the heat of the control circuit 15 that convects in the space P is convected to the protective cover 30. Heat transfer can be facilitated, and the temperature of the protective cover 30 can be further increased.

  Further, the lighting unit 100 of the present embodiment forms the reflective surfaces 28 and 29 by forming the reflective film 26 on the transparent resin layer 87, and directs the light L incident from the LED element 14 to the outside of the protective cover 30. Therefore, it is not necessary to separately provide a partition member for partitioning the narrow space P separately from the reflector 20, so that the number of parts can be reduced to simplify the configuration and reduce the cost. it can.

  Further, in the lighting unit 100 of the present embodiment, the area S2 of the surface facing the protective cover 30 in the space P formed by being surrounded by the protective cover 30 and the concave portion 83 of the reflector 20 is reflected by the reflective surfaces 28 and 29 to be protected. Since the area is smaller than the area S1 of the region where the light L is emitted from the cover 30 to the outside, the space P in which heat is convected can be limited to a narrow region, and the degree of heat diffusion can be reduced.

  That is, even if the volume of the space P of the recesses 83, 84, 85 formed by being surrounded by the protective cover 30, the transparent resin layer 87, and the support portion 86 is small, the protective cover 30 faces the space P. When the space is large and the dent is thin, it is possible to secure a large area of the surface from which the light L is emitted to the outside, but the heat from the circuit board 11 serving as a heat source is protected by the protective cover 30. The temperature is raised over a wide range, and the temperature is less likely to rise.

  On the other hand, as in the present embodiment, if the area S2 of the surface where the protective cover 30 faces the partitioned space P is formed so that the area S1 of the region through which the light L passes is also narrow, The degree of diffusion can be reduced and the temperature tends to rise.

  In addition, since all the recessed parts 83, 84, and 85 are formed so that the curvature may change smoothly (continuously), the light L emitted from the LED element 14 to the closed space P is transparent resin layer 87. The traveling direction of the light L can be continuously changed by entering the light and reaching the reflecting surfaces 28 and 29.

  Similarly, the traveling direction of the light L can be continuously changed by the emission of the light L reflected by the reflecting surfaces 28 and 29 from the transparent resin layer 87 and reaching the protective cover 30.

  Therefore, the intensity distribution of the light L visually recognized outside the lighting unit 100 can be changed smoothly.

  The lighting section 100 of the present embodiment uses the spiral circuit board 11, but the circuit board in the light emitting device according to the present invention is not limited to this embodiment, and the reflecting surface 28. , 29 can be applied to any shapes and characteristics as long as they have gaps or transparency through which the reflected light L can be transmitted to the outside.

  Since the circuit board 11 is disposed on the optical path of the light L reflected by the reflecting surfaces 28 and 29, the amount of blocking the reflected light L increases as the width W of the circuit board 11 increases. .

  Therefore, it is desirable that the width W be as narrow as possible or have a transparency that does not prevent the passage of the light L.

  The above-described embodiment is an example in which the light-emitting device according to the present invention is applied to the lighting unit 100 of the traffic signal lamp 200. However, the light-emitting device according to the present invention is not limited to this embodiment, and a street light, It can be applied to lighting equipment.

  Further, since the lighting unit 100 of the present embodiment, which is a reflective light emitting device, can emit the emitted light L from the LED element 14 to the outside with high efficiency, the conventional non-reflective LED traffic signal light is illuminated. Compared to the portion, the number of LED elements 14 can be greatly reduced, and the cost can be reduced.

  For example, a lighting part of a non-reflective traffic signal lamp using LEDs uses hundreds to hundreds of LEDs, but the lighting part 100 of the present embodiment has only 31 LED elements. 14, the visibility comparable to or higher than that of a conventional non-reflective signal lamp can be obtained.

  In addition, since glare can be reduced, it is suitable as the lighting unit 100 of the traffic signal lamp 200 that is directly viewed by the driver of the vehicle.

  Further, the conventional traffic signal light using a non-reflective LED signal lamp has a noticeable graininess, and if the number of LED elements is extremely reduced, the original circular shape cannot be expressed, but the lighting unit 100 of the present embodiment. Can realize substantially surface light emission with reduced graininess, so that a visibility equal to or higher than that of the conventional one can be obtained by using a small number of LED elements 14.

11 Circuit board 11m One surface 11n Opposite surface 14 LED element (light emitting element)
14a Light emitting surface 14b Back surface 15 Control circuit 16 Terminal 20 Reflector (reflective member)
26 Reflective film 28, 29 Reflective surface 30 Protective cover (cover)
31 Front surface 32 Back surface 40 Unit case 50 Waterproof rubber packing 60 Heat insulating material 70 Connector 83, 84, 85 Concave part 86 Support part (support member)
87 Transparent resin layer 100 Light part (light emitting device)
200 traffic light L light

Claims (3)

A light-transmitting cover; a circuit board on which a plurality of light emitting elements are mounted on one surface side; and a surface opposite to the one surface is in contact with the cover; and the cover with respect to the circuit board; In a light emitting device having a reflective member disposed on the opposite side and reflecting light from the light emitting element,
A support member for supporting the reflection member on the cover;
The light-emitting element is surrounded by a closed narrow space by a surface formed so that the curvature continuously changes on the side of the support member, the cover, and the reflective member close to the light-emitting element,
A light emitting device characterized in that light emitted from the light emitting element is reflected by a surface of the reflecting member on a side far from the light emitting element.   The light emitting device according to claim 1, wherein the supporting member is formed as a part of the reflecting member. A number of light emitting elements are mounted on the circuit board along the extending direction,
A large number of these light-emitting elements are divided into a plurality of groups having a plurality of light-emitting elements for each group, and are connected.
When a rectified voltage for driving the light emitting element is applied to the group, a connection form between the plurality of groups is selected from one of a parallel connection and a series connection, or a parallel connection and a series, depending on the magnitude of the rectification voltage. A control circuit that switches to a combination of connections is provided between each of the groups,
The light emitting device according to claim 1, wherein the support member surrounds the control circuit together with the cover and the reflection member.