JP6386808B2 - Lighting device - Google Patents

Description

  The present invention relates to an illumination device using an LED light source.

  As a light source for lighting devices such as ceiling lights and base lights, LEDs are being used in place of conventional fluorescent lamps and incandescent lamps in order to consider the environment and reduce power consumption. The LED light source has a light distribution different from that of conventional fluorescent lamps and incandescent lamps, and has the highest luminous intensity toward the front of the light source.

  When an LED light source is used, the front surface of the light source is illuminated brightly, and the arrangement direction of the light source becomes important. For example, in a lighting device, it is preferable that the light emitting surface emits light uniformly over a wide range, but there is a problem that light does not reach in the direction away from the front of the light source and becomes dark. In order to solve this, there is a countermeasure method such as changing the arrangement direction of the light source toward the direction of darkening. However, the direction of the light source restricts the arrangement direction of the light source substrate on which the light source is arranged. In many cases, the light source board also has a function of efficiently exhausting heat generated from the light source, and the light source board has a wide contact area with a structure such as a casing, chassis, and heat radiating fin that are relatively excellent in heat conduction. It is desirable that they are arranged. In view of such circumstances, changing the arrangement direction of the light source changes the direction of the light source substrate, which makes it difficult to arrange in consideration of heat dissipation, and deteriorates the performance of the lighting device due to insufficient heat dissipation. In the case of a design that prioritizes heat dissipation, the structural design specialized in the arrangement of the light source substrate may cause an increase in the structural cost. In view of heat dissipation and manufacturing cost, it is desirable that the light source substrate is realized by a flat substrate.

  As a technique related to the arrangement direction of the light source, for example, one described in Patent Document 1 is known. Patent Document 1 includes a light source substrate in which a long band-shaped substrate is curved in a substantially annular shape, a plurality of LED (light emitting diode) elements disposed on the light source substrate, and the light source substrate, Power supply means for supplying power to the LED element, and a plurality of convex portions are arranged in a rectangular wave shape along a circumferential direction on either the lower part or the upper part of the light source substrate, or on the lower part and the upper part. Each of the portions is curved or bent toward the radial direction, whereby a substrate surface facing a specific direction is formed on the convex portion, and the LED element is arranged on the substrate surface facing the specific direction. A lighting device is disclosed (see summary).

  If it is the said structure, since it is necessary to implement | achieve arrangement | positioning which faces a board | substrate surface in a specific direction, it is difficult to implement | achieve with one plane board | substrate, It divides | segments into several board | substrates, or it depends on the board | substrate bent Although realization methods are conceivable, all of them tend to increase the manufacturing cost.

JP 2013-65427 A

  In the invention described in Patent Document 1, it is necessary to arrange the light source substrate so as to face a specific direction. Since there is a limitation on the arrangement direction of the light source substrate, it is necessary to divide the substrate into a plurality of substrates or use a substrate that can be bent with a relatively high cost material, which makes it difficult to realize an inexpensive lighting device.

  On the other hand, a method using reflection is also conceivable as a method of bending the direction of the light beam. In the case of a luminaire using an LED light source, a cover of a transparent member is provided so as to cover the LED surface from the viewpoint of safety, and it is not necessary to configure a reflector using this transparent member. It is convenient. It is ideal to use total reflection as a reflector using a transparent member. However, when the total reflection is incident at an angle smaller than the angle defined by the following critical angle, the total reflection does not occur, and most of the light rays come out of the member. For example, when a transparent member having a paraboloid shape as shown in FIG. 4 is considered, light emitted from the focal point of the paraboloid becomes leakage light at a portion below the critical angle. In order to solve this, as shown in FIG. 5, since it is necessary to keep the incident angle at or above the critical angle, there is a problem that the height is increased and the overall shape is increased.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an inexpensive and small illumination device capable of directing light from an LED light source toward a peripheral portion or a central portion.

In order to solve the above-described problems, the present invention employs the configurations described in the claims.
The present invention includes a plurality of means for solving the above-described problems. If an example of the lighting device of the present invention is given,
An illumination device including a plurality of LEDs and a reflector made of a light-transmitting member, wherein the reflector is opposed to the plurality of LEDs on an LED substrate and reflects light incident from the LEDs in a substantially perpendicular direction. And the outer surface of the reflector is formed with a roof-shaped groove parallel to the light emission direction so that light is directed in a right angle direction by two total reflections, and the existence range of the roof-shaped groove is The groove ridgeline and the incident light from the LED are limited to a portion having a critical angle or less, and a minute unevenness is provided on the reflecting surface of the reflector .

  ADVANTAGE OF THE INVENTION According to this invention, the cheap and small illuminating device which can direct the light of a LED light source to a peripheral part or a center part can be provided.

The figure for demonstrating the structure of the illuminating device which concerns on this invention. The figure for demonstrating the basic structure of the illuminating device of this invention. The figure for demonstrating the whole structure of the reflector which consists of a transparent member of the illuminating device of this invention. The figure for demonstrating a paraboloid and a critical angle. The figure for demonstrating an equiangular spiral reflective surface. The figure for demonstrating the Example of this invention. The figure for demonstrating the cross-section of the reflective surface of Example 1 of this invention, and a light ray state. The figure for demonstrating the change of the cross-section of Example 2 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that components having the same function are denoted by the same names and reference numerals in the drawings for describing the embodiments, and repetitive description thereof is omitted.

  FIG. 1 is a sectional structure of a ceiling light to which the present invention is applied. The ceiling light diffuses the light emitted from the LED element 11 mounted on the LED mounting substrate 12 on the appliance chassis 6 through the reflector 4 made of a transparent member having a lens function, and illuminates the shade 14 from the inside, thereby The surface is kept at a uniform brightness and the room is illuminated. The present invention is characterized by the structure of the reflector (reflector) 4 made of this transparent member.

  FIG. 2 is an enlarged view for explaining a portion related to the present invention of the ceiling light of FIG. A large number of the LED elements 11 are electrically connected to the power source 13 via the LED mounting substrate 12 and emit light. In the case of the embodiment of the present invention, among the many LED elements 11 arranged, a transparent light that reflects and deflects light rays from the LEDs arranged at the outermost circumference or the innermost circumference in a direction substantially perpendicular to the direction of the substrate surface. A reflector 4 made of a member is disposed. The reflector 4 has a reflecting surface 2 having a substantially parabolic shape, and a light beam incident from the incident surface 1 is totally reflected by the reflecting surface 2 and is emitted from the emitting surface 7 while changing its direction by approximately 90 °.

  FIG. 3 is a perspective view when this structure is set on the outer peripheral portion of the lighting device. The light from the LED light source 11 is totally reflected by the reflecting surface 2 and is emitted as an emitted light beam 8 toward the peripheral portion. Although not shown, this structure may be set in the inner peripheral portion of the lighting device. In this case, the light from the LED light source is totally reflected by the reflecting surface and emitted toward the central portion.

FIG. 4 shows a state of reflection when a parabolic surface is used as the structure of the reflecting surface 2. Reference numeral 3 represents a light emitting point. When light traveling from the inside of the reflector 4 toward the surface reaches the surface, refraction and reflection occur according to Snell's law. At this time, there is a critical angle δc determined from the following relationship.
sinδc = 1 / n
Here, n is the refractive index of the transparent member. For example, when polycarbonate (n = 1.59) is used as the transparent member,
δc = 38.97 °
It becomes. A light ray incident at an angle closer to the surface normal than the critical angle does not cause total reflection and is refracted from the reflecting surface 2. On the other hand, light incident at an angle larger than the critical angle causes total reflection at the reflecting surface 2, and 100% of the incident light beam is reflected. Thus, total reflection is an extremely efficient reflection method, but the problem is that a critical angle limit occurs. In the case of this example, the incident light beam having a smaller angle than the critical angle leaks from the reflecting surface without being reflected, and the light beam cannot be directed in a desired direction.

  FIG. 5 shows an example in which the reflecting surface 2 is configured so that there is no incident angle smaller than the critical angle. The shape of this surface is a curved surface obtained by continuously connecting the surfaces where the incident angle of the light beam emitted from the light source 3 always maintains a value larger than the critical angle δc. When the angle is constant, the shape is an equiangular spiral. When this surface is used, since the incident angles of all the light rays are larger than the critical angle, all the rays are totally reflected. However, as can be seen from the figure, the height of the surface is inevitably high, and there arises a problem that the light flux from the adjacent LED is shielded and becomes a shadow on the shade.

  With reference to FIG. 6, an embodiment in which the reflector utilizing total reflection according to the present invention is applied to the reflecting surface 2 will be described. In the present invention, a substantially V-shaped groove (roof-shaped groove) whose ridge is parallel to the emission direction is formed on the surface of the reflecting surface 2, and this is used as a total reflection prism to reflect the light beam twice on the V-shaped surface. As a result, the light beam is reflected in a substantially perpendicular direction. In the present invention, a rooftop prism is formed by a substantially V-shaped groove.

  FIG. 7 shows a cross-sectional structure of the reflecting surface 2. A large number of grooves having a V-shaped surface having a substantially V-shaped ridge 10 and a valley 9 are arranged on the reflecting surface. By using such a V-shaped surface, the incident light beam 8 can be folded back in the original direction by two reflections. When this structure is used, even when the angle of the reflecting surface 2 is smaller than the critical angle when viewed from the direction perpendicular to the paper surface of FIG. Total reflection can be achieved by exceeding the critical angle. The surface of the V-shaped surface does not necessarily have to be a flat surface, and may be a curved surface suitable for the light source position and the emission direction, or a surface having small irregularities to add a certain degree of diffusion characteristics. Also good.

  Further, it is not necessary to add this V-groove to the entire surface of the reflecting surface 2, and this structure may not be added to a surface having an angle larger than the point 5 that is just a critical angle when viewed from the light source.

  In Example 2, the groove shape is changed according to the position of the reflecting surface 2.

  FIG. 8 is a diagram for illustrating changes in the groove shape in the above example. When the incident angle to the reflecting surface 2 is small, the V-groove angle needs to be deep in order to be a critical angle. However, as the incident angle increases, the condition of the critical angle on the V-groove surface is relaxed. Therefore, the groove can be formed shallow. There is no problem with light that is parallel to the paper surface even in a deep V-groove, but in reality there are also rays in the direction intersecting the paper surface, so it is preferable that the angle of the surface of the V-groove is small. It is desirable that the angle is adjusted to an appropriate angle according to the amount of the light beam parallel to the light beam and the amount of the light beam in the direction intersecting the paper surface. Further, beyond the critical angle point 5, even if there is no V-groove, it is incident at an angle larger than the critical angle, resulting in total reflection.

  Of course, the V-groove may be formed on the entire surface, or the V-groove may exist before the point 5 that is the critical angle.

  In addition, although the surface of the exit surface 7 is a flat surface in the embodiment, a curved surface may be used on this surface to control the direction of light, or a minute unevenness may be provided to add scattering, A lens array or prism array may be added.

  As described above, when the present invention is applied, it is possible to obtain an optical system that efficiently bends light rays from an LED in a perpendicular direction, and low-loss optics that brightly illuminate the shade surface in the central portion and the peripheral portion where no LED exists. A system can be constructed.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

1 Incident surface 2 Reflecting surface 3 Light emitting point 4 Reflector (reflector)
5 Critical angle position 6 Instrument chassis 7 Emission surface 8 Emission light beam 9 Reflection surface valley portion 10 Reflection surface mountain portion 11 LED element 12 LED mounting substrate 13 Power supply 14 Sade

Claims (10)

An illumination device including a plurality of LEDs and a reflector made of a light transmissive member,
Opposing the plurality of LEDs on the LED substrate, the reflector that reflects light incident from the LEDs in a substantially right angle direction is disposed,
The outer surface of the reflector has a roof-shaped groove formed in parallel to the light emission direction so as to direct light in a right angle direction by total reflection twice.
The existence range of the roof-shaped groove is limited to a portion where the ridge line of the groove and the incident light from the LED are equal to or less than a critical angle ,
An illuminating device characterized in that minute irregularities are provided on a reflecting surface of the reflector . The lighting device according to claim 1.
The illuminating device, wherein the reflector is disposed with an emission direction outward along an outer peripheral portion of the LED substrate on which the plurality of LEDs are placed. The lighting device according to claim 1.
The illuminating device, wherein the reflector is arranged with an emission direction inward along an inner peripheral portion of the LED substrate on which the plurality of LEDs are placed. The lighting device according to claim 1.
The lighting device according to claim 1, wherein the shape of the cross section of the groove on the outer surface of the reflector is a V-shaped groove. The lighting device according to claim 4.
A lighting device, wherein the shape of the cross section of the groove on the outer surface of the reflector is a V-shaped groove having an apex angle of 90 degrees. An illumination device including a plurality of LEDs and a reflector made of a light transmissive member,
Opposing the plurality of LEDs on the LED substrate, the reflector that reflects light incident from the LEDs in a substantially right angle direction is disposed,
The outer surface of the reflector has a roof-shaped groove formed in parallel to the light emission direction so as to direct light in a right angle direction by total reflection twice.
The angle of the V-shaped surface of the cross section of the groove on the outer surface of the reflector is changed according to the angle of the ridge line and the incident light beam ,
An illuminating device characterized in that minute irregularities are provided on a reflecting surface of the reflector . An illumination device including a plurality of LEDs and a reflector made of a light transmissive member,
Opposing the plurality of LEDs on the LED substrate, the reflector that reflects light incident from the LEDs in a substantially right angle direction is disposed,
The outer surface of the reflector has a roof-shaped groove formed in parallel to the light emission direction so as to direct light in a right angle direction by total reflection twice.
The angle of the V-shaped surface of the cross section of the groove on the outer surface of the reflector is changed according to the angle of the ridge line and the incident light beam,
When the angle between the ridge line and the incident light beam is small, the angle of the V-shaped surface is increased, and as the angle between the ridge line and the incident light beam is increased, the angle of the V-shaped surface is decreased. A lighting device. The lighting device according to claim 7 .
Lighting device characterized by the reflecting surface of the reflector is provided with infinitesimal irregularities. In the illuminating device as described in any one of Claims 1-8,
An illumination device, wherein a light exit surface of the reflector is provided with a curved surface or minute irregularities, or a microlens array or a prism array is provided. In the illuminating device as described in any one of Claims 1-9,
A lighting device is provided with a shade so as to surround the plurality of LEDs and the reflector.

Images