JP2014239008A - Lighting fixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting fixture which makes light in a lateral direction emit as much as possible while suppressing deterioration of illuminance right below, and which can suppress uncomfortable glare.SOLUTION: A lighting fixture 10 includes: an LED chip 111 which becomes a light source; a convex lens part 131 arranged in front of the LED chip 111; and a reflector plate 142 for surrounding the periphery of the convex lens part 131. In the lighting fixture 10, due to an opening degree of an opening edge part 142a of the reflection plate 142 with the center of the LED chip 111, where luminance becomes highest, being reference, in a virtual plane including an optical axis A, the opening edge part 142a of the reflection plate 142 is located in a region S sandwiched between a first virtual straight line L1 and a second virtual straight line L2. The first virtual straight line L1 is a straight line showing the outermost side optical path where light from the light source center advances inside the reflection plate 142 by passing through the convex lens part 131. The second virtual straight line L2 is a tangential line of the convex lens part 131, and an angle formed with the direction orthogonal to the optical axis A becomes equal to or more than a minimum light shielding angle θ.

Description

  The present invention relates to a lighting fixture used as a downlight or a pendant light and having a reflector.

What was described in patent document 1 as a lighting fixture which has a reflecting plate is known.
The “lighting fixture” described in Patent Document 1 is set at a predetermined glare cut angle by a substantially bowl-shaped reflector and a substantially dome-shaped diffusion cover protruding inside the reflector, and is emitted from the LED chip. The diffused light is diffused by the unevenness of the diffusion cover and emitted in the lateral direction, giving a wide range of light that increases the sense of space brightness with less energy while suppressing light loss and glare generation It can be done.

JP 2011-129473 A

In the “lighting fixture” described in Patent Document 1, light in the lateral direction is obtained by the diffused light from the diffusion dome and the reflected light from the reflector. However, the light in the lateral direction tends to cause unpleasant glare. Glare is an unpleasant vision that occurs when a high-luminance portion enters the field of view, and it is considered desirable for a lighting fixture to cut it.
In order to block the light in the lateral direction, the opening degree of the reflecting plate may be reduced. For example, in the case of the “lighting fixture” described in Patent Document 1, it is conceivable that the reflector has a large glare cut angle. However, a large amount of light from the light source is reflected on the reflector and is directly below. Since the amount of light that illuminates is reduced, the illuminance directly below falls.

  Therefore, an object of the present invention is to provide a luminaire that can emit light in the lateral direction as much as possible and suppress unpleasant glare while suppressing a decrease in direct illuminance.

  The present invention relates to a lighting fixture including a light source, a convex lens unit disposed in front of the light source, and a reflector surrounding the convex lens unit, in a virtual plane including the optical axis of the light source, A first imaginary straight line indicating an outermost optical path in which light emitted from the center passes through the convex lens portion and travels inside the reflector, and a second imaginary straight line indicating a tangent to the convex lens portion, The opening edge of the reflector is located in a region sandwiched between a second imaginary straight line in which an angle formed with a direction orthogonal to the optical axis of the light source is equal to or greater than a minimum light shielding angle. .

  According to the lighting apparatus of the present invention, the first imaginary straight line indicates the outermost optical path in which the light emitted from the center of the light source passes through the convex lens portion and travels inside the reflecting plate. If this angle is more than this, it indicates that the light emitted from the convex lens portion does not reach the reflector. Therefore, it is possible to suppress a reduction in the amount of light that is reflected from the light source and travels in a direction different from the direct lower direction to illuminate the direct lower direction. Further, if the second imaginary straight line indicating the tangent line of the convex lens part is equal to or larger than the minimum light shielding angle as an angle formed with the direction orthogonal to the optical axis of the light source, unpleasant glare can be suppressed.

The minimum light shielding angle θ is preferably an angle indicated by the following conditions a to d.
Condition a: When the luminance is less than 20,000 cd / m ² θ = 10 °
Condition b: When luminance is 20,000 cd / m ² or more and 50,000 cd / m ² θ = 15 °
Condition c: luminance 50,000cd / m ² or more, when the 500,000cd / m ² θ = 20 °
Condition d: When luminance is 500,000 cd / m ² or more θ = 30 °
The minimum shading angle at which it begins to feel unpleasant glare depends on the brightness. This minimum light-shielding angle can be from condition a to condition d. Therefore, the minimum light-shielding angle θ can be ensured by using the second imaginary straight line as the opening edge of the reflector satisfying the conditions a to d.

  It is desirable that the exit surface of the convex lens portion is formed to be a rough surface. If the light from the light source is refracted at a more angle at the convex lens part, an orange ring may be formed on the exit surface due to chromatic aberration. If the exit surface is a rough surface, this chromatic aberration can be alleviated and the orange ring formed on the exit surface can be eliminated.

  It is desirable that the reflection surface of the reflection plate is subjected to a light diffusion reflection process. Light from the center of the light source travels inside the first virtual line, but light that deviates from the center of the light source may travel outside the first virtual line. Further, if the exit surface of the convex lens portion is a rough surface, the light diffused by the exit surface may travel outside the first virtual straight line. By traveling outside the first imaginary straight line, the light that has reached the reflecting plate is subjected to light diffusion reflection processing on the reflecting surface, and can therefore be reflected and emitted forward by the reflecting surface. It can be a lighting fixture.

  The present invention can prevent the light from the light source from being reflected by the reflecting plate and proceeding in a direction different from the direction directly below to reduce the amount of light that illuminates directly below, and the reflecting plate ensures a minimum light shielding angle. Therefore, it is possible to emit light in the lateral direction as much as possible and suppress unpleasant glare while suppressing a decrease in illuminance directly below.

It is sectional drawing which shows the lighting fixture which concerns on this Embodiment 1. FIG. It is sectional drawing for demonstrating the reflecting plate of the lighting fixture shown in FIG. It is sectional drawing for demonstrating the minimum light-shielding angle of the lighting fixture shown in FIG. It is sectional drawing for demonstrating the spreading | diffusion of the output surface of the convex lens part of the lighting fixture shown in FIG. 1, and the diffuse reflection of the reflective surface of a reflecting plate. It is sectional drawing for demonstrating that the incident of the white light to the convex lens part of the lighting fixture shown in FIG.

(Embodiment 1)
The lighting fixture which concerns on Embodiment 1 of this invention is demonstrated based on drawing. In this specification, the direction of emission from the light source is referred to as the front, and the opposite direction is referred to as the rear. In addition, a direction that intersects the optical axis at a right angle and is away from the optical axis is referred to as an outer direction, and the opposite direction is referred to as an inner direction.

A lighting fixture 10 shown in FIG. 1 includes a COB (Chip on Board) type LED module 11, an LED holder 12 that holds the LED module 11, a lens 13 that controls the orientation of light of the LED module 11, and a fixture body 14. It has.
In the LED module 11, a plurality of LED chips 111 that emit blue light are arranged on a substrate 112, and a yellow phosphor that emits light that has been excited by blue light and converted in wavelength is applied to seal the LED chip 111. is there.

  The LED holder 12 is formed in a ring shape, and is fixed to a concave portion on the front surface of the housing portion of the instrument main body 14 with a screw (not shown), thereby arranging and holding the LED module 11 in the concave portion. Most of the light from the LED module 11 passes through the central cavity of the LED holder 12, but a part of the light emitted from the LED module 11 in the lateral direction is reflected by the inner wall surface of the LED holder 12 and diffused. Therefore, the LED holder 12 is formed of a white resin having a diffuse reflection property.

The lens 13 includes a convex lens portion 131 in which the optical axis A is aligned with the central axis of the lighting fixture 10, and a pedestal portion 132 for fitting into the fixture body 14. The lens 13 is formed by molding a transparent resin such as polycarbonate or acrylic.
The convex lens part 131 is formed in a substantially hemispherical shape, and is disposed in front of the LED chip 111 that is a light source. The convex lens part 131 is formed of a colorless and transparent member, and the surface is formed as a smooth surface without irregularities. Therefore, the light emitted from the convex lens part 131 travels without being diffused.
The pedestal 132 has a flange 132a that extends outward from the periphery of the convex lens 131 and a standing wall 132b that stands from the periphery of the flange. The standing wall portion 132 b is fitted into the instrument main body 14.

The instrument main body 14 includes a casing portion 141 formed in a cylindrical shape and a reflecting plate 142 that surrounds the convex lens portion 131.
The housing unit 141 includes a power supply unit that supplies current to the LED module 11. The reflection plate 142 is formed on an inclined surface having a circular opening area that gradually increases in the light emission direction. The inner surface of the reflecting plate 142 is a reflecting surface 142b that has been subjected to a diffuse reflection process.

Here, the convex lens part 131 and the reflecting plate 142 of the lighting fixture 10 are demonstrated based on drawing.
As shown in FIG. 2, the opening degree of the opening edge 142 a of the reflecting plate 142 based on the center of the plurality of LED chips 111 having the highest luminance (hereinafter referred to as the light source center) includes the optical axis A. In the virtual plane, it is determined from the first virtual straight line L1 and the second virtual straight line L2.
When this virtual plane includes the optical axis A, the first virtual straight line L1 and the second virtual straight line L2 can be shown as straight lines on the cross-sectional view of the lighting fixture 10 shown in FIG.

The first imaginary straight line L <b> 1 indicates the progress of light that has passed through the outermost side of the convex lens portion 131 among the light emitted from the central portion of the LED 111.
Of the incident surface 131a of the convex lens part 131, the light incident on the outermost side is at an angle θ ₀ with respect to the optical axis A, but since the refractive index of the convex lens part 131 is larger than “1”, it is refracted inward. Further, the light is also refracted inward on the light exit surface 131b, and becomes light with an angle θ ₁ (here θ ₀ > θ ₁ ) with respect to the optical axis A. This emitted light is the light that goes outward with respect to the optical axis A in the emitted light from the center of the light source. This optical path is indicated by a first virtual straight line L1.

Next, the second virtual straight line L2 will be described. The unpleasant vision that occurs when a high-luminance part enters the field of view is referred to as glare, and it is desirable for a lighting fixture to block this glare.
As shown in FIG. 3, when viewed from an observer positioned obliquely below the luminaire 10, the convex lens portion 131 is not dazzled unless the convex lens portion 131 is shielded and observed by the reflector 142. However, if the degree of opening of the reflecting plate 142 is large and the convex lens part 131 can be observed by an observer, it will be felt dazzling.

In order to prevent glare (glare) on the exit surface 131b of the convex lens part 131, the following conditions a to d are defined in JIS Z9125 “Indoor Workplace Lighting Standard” according to the luminance of the light source. ing. Here, the angle θ ₂ shown in FIG. 2 is an angle formed between the second imaginary straight line L 2 that is a tangent to the emission surface 131 _b of the convex lens portion 131 and the direction orthogonal to the optical axis A. This angle θ ₂ is also called a glare cut angle or a minimum light shielding angle. JIS Z9125 stipulates that the minimum light shielding angle must not be less than the value of this angle θ ₂ .

Condition a: When the luminance is less than 20,000 cd / m ² θ ₂ = 10 °
Condition b: When the luminance is 20,000 cd / m ² or more and 50,000 cd / m ² θ ₂ = 15 °
Condition c: luminance 50,000cd / m ² or more, 500,000cd / m when theta ₂ = 20 ° of the ²
Condition d: When luminance is 500,000 cd / m ² or more θ ₂ = 30 °

On the spherical surface which is the exit surface 131b of the convex lens part 131, a tangent line with an angle θ ₂ is defined as a second virtual straight line L2. For example, if the luminance of the LED module 11 is 500,000 cd / m ² or more, θ ₂ is 30 °. The intersection point of the first virtual line L1 and the second virtual line L2 is a point P.
The reflection plate 142 has an opening edge 142a (point Q) located in a region S sandwiched between the first virtual line L1 and the second virtual line L2 with the point P as an apex. An opening degree is formed.

If the position of the opening edge 142a of the reflecting plate 142 indicated by the point Q is within the region S, the point Q is positioned ahead of the second imaginary straight line L2. Accordingly, the angle θ ₃ formed by the third imaginary straight line L3 that is a tangent to the exit surface 131b of the convex lens portion 131 that passes through the point Q and the direction orthogonal to the optical axis A is larger than the angle θ _{2. 3} can secure an angle θ ₂ or more which is the minimum light shielding angle.
Therefore, since the opening degree of the reflecting plate 142 can ensure the minimum light shielding angle, the glare to the observer can be suppressed.

  Further, since the point Q indicating the opening edge 142a of the reflecting plate 142 is located on the rear side of the first imaginary straight line L1, the light emitted from the emitting surface 131b passing through the convex lens portion 131 from the center of the light source is reflected by the reflecting plate. 142 is not reached. Therefore, when the reflection plate 142 is formed so that the opening edge 142a is located in the region S, the light from the convex lens portion 131 does not reflect on the reflection plate 142 but directly illuminates the direction directly below the reflection plate 142. And the fall of the illumination intensity right under the lighting fixture 10 can be prevented.

  As described above, in the lighting fixture 10, the opening edge 142a of the reflector 142 is located in the region S sandwiched between the first virtual line L1 and the second virtual line L2 having the point P as the vertex. It is possible to emit light in the lateral direction as much as possible and suppress unpleasant glare while suppressing a decrease in direct illuminance.

In the first embodiment, since the first virtual straight line L1 is determined based on the light from the light source center having the highest luminance, the emitted light from the convex lens portion 131 does not reach the reflecting plate 142. However, in the light emitted from the outside of the center of the light source and the light diffusely reflected by the LED holder 12, there is also light traveling outside the first virtual straight line L 1, and the light reaches the reflection plate 142. There are things to do.
However, since most of the light from the LED module 11 does not reach the reflecting plate 142 and is not affected by the reflectance of the reflecting plate 142, the lighting device 10 can be made efficient.

(Embodiment 2)
The lighting fixture which concerns on Embodiment 2 of this invention is demonstrated based on drawing. In FIG. 4, the same components as those in FIG. 1 and FIG.
In the lighting fixture 10x shown in FIG. 4, the reflector 142 of the fixture body 14 is the same as the reflector 142 of the lighting fixture 10 according to Embodiment 1 shown in FIG. 2, and the opening edge 142a shown in FIG. It is formed so as to be located in the region S shown in FIG.
The lighting fixture 10x according to the second embodiment is characterized in that the exit surface 131b of the convex lens portion 131x is formed into a rough surface, and the reflective surface 142b of the reflector 142x is coated with white paint.

Since the convex lens portion 131 according to Embodiment 1 is colorless and transparent and the exit surface 131b is formed of a smooth surface, it does not include any diffusing elements. In the case of such a convex lens portion 131, when the degree of refraction is increased and the refraction angle is increased, unpleasant chromatic aberration may occur in the irradiation pattern.
In general, a convex lens used in a lighting fixture is formed of, for example, a transparent resin such as polycarbonate or acrylic, and light is refracted by a refractive index unique to the material. However, the refractive index inherent to this material is not constant, varies depending on the wavelength of incident light, and an event called dispersion occurs.

  Therefore, as shown in FIG. 5, the actual optical path is slightly shifted from the optical path set by the optical design for each wavelength of light, and the incident of white light is spectrally decomposed to become rainbow-colored outgoing light. . However, if there is only one optical path, it is decomposed into rainbow colors, but most of the entire lighting fixture is mixed with rainbow-colored outgoing light in other optical paths, so most of the light mixes and returns to white. However, only the outermost surface of the exit surface 131b of the convex lens portion 131 has no light to be mixed, so that a ring of light with a red to yellow color remains, and an orange ring may be formed on the exit surface. .

  Therefore, in the lighting fixture 10x according to the second embodiment, the exit surface 131b of the convex lens portion 131x is formed into a rough surface. By doing so, the iridescent light spectrally resolved by the chromatic aberration emitted from the exit surface 131b is scattered by the fine irregularities of the convex lens portion 131x and mixed with the white light, thereby eliminating the orange ring formed on the exit surface 131b. And makes chromatic aberration inconspicuous.

  White light due to this scattering spreads from the optical path of the optical design of the convex lens part 131. That is, some of the scattered light travels outside the first virtual straight line L1 shown in FIG. Accordingly, some of the light traveling outside the first imaginary straight line L1 reaches the reflecting surface 142b of the reflecting plate 142. However, since the reflecting surface 142b of the reflecting plate 142 has a white coating on the surface, it is diffusely reflected by the white coating of the reflecting surface 142b of the reflecting plate 142, and becomes illumination light that irradiates the floor and wall surfaces.

The fine irregularities on the exit surface of the convex lens portion 131x are such that the chromatic aberration is inconspicuous and the depth is very shallow. Therefore, the fine unevenness of the emission surface 131b does not spread the emission width by diffusing all the emission light from the emission surface 131b. Therefore, most of the emitted light from the emission surface 131b does not reach the reflector 142 according to the optical design of the convex lens part 131, and is directly irradiated to the floor surface and the wall surface.
Most of the light emitted from the emission surface 131b does not reach the reflection surface 142b of the reflection plate 142, and thus is not affected by the reflectance of the reflection plate 142. Therefore, since the light is not attenuated by being reflected by the reflecting plate 142, the lighting fixture 10 can be made efficient.
In the second embodiment, the white coating is applied as the light diffusing reflection process applied to the reflecting surface 142b of the reflecting plate 142, but the blasting process, the printing of the light diffusing reflective paint, and the application of the light diffusing reflective sheet are performed. And so on.

  The present invention is suitable for a downlight or a pendant light with a reflector.

DESCRIPTION OF SYMBOLS 10,10x Lighting fixture 11 LED module 111 LED chip 112 Board | substrate 12 LED holder 13,13x Lens 131,131x Convex lens part 131a Incidence surface 131b Outgoing surface 132 Base part 132a Gutter part 132b Standing wall part 14 Instrument body 141 Housing part 142,142x Reflector 142a Opening edge 142b Reflecting surface a to d Condition A Optical axis L1 First virtual straight line L2 Second virtual straight line L3 Third virtual straight line Q point S region θ _{1 to} θ ₃ angle

Claims (4)

In a luminaire comprising a light source, a convex lens part arranged in front of the light source, and a reflector surrounding the convex lens part,
A first imaginary straight line indicating an outermost optical path in which light emitted from the center of the light source passes through the convex lens portion and travels inside the reflecting plate in a virtual plane including the optical axis of the light source; The reflection is performed in a region between a second virtual straight line indicating a tangent line of the convex lens portion and an angle between a direction perpendicular to the optical axis of the light source and a minimum light shielding angle. A lighting fixture, wherein an opening edge of a plate is located. The lighting apparatus according to claim 1, wherein the minimum light shielding angle θ is an angle indicated by the following conditions a to d.
Condition a: When the luminance is less than 20,000 cd / m ² θ = 10 °
Condition b: When luminance is 20,000 cd / m ² or more and 50,000 cd / m ² θ = 15 °
Condition c: luminance 50,000cd / m ² or more, when the 500,000cd / m ² θ = 20 °
Condition d: When luminance is 500,000 cd / m ² or more θ = 30 °   The illuminating device according to claim 1, wherein an exit surface of the convex lens portion is formed into a rough surface.   The lighting fixture according to any one of claims 1 to 3, wherein the reflection surface of the reflection plate is subjected to a light diffusion reflection process.

Images