A European standard compliant LED emergency lighting lens

Abstract

This invention provides an LED emergency lighting lens conforming to European standards. The lens includes a main body with a rotational symmetry axis. The main body comprises a receiving cavity for housing an LED light source, an incident surface forming a light-gathering cavity, an exit surface, and a medium located between the incident and exit surfaces. Both the incident and exit surfaces are freeform surfaces, and are rotationally symmetric along the rotational symmetry axis. The medium has the smallest thickness at the rotational symmetry axis, and its thickness increases with distance from the axis. By using freeform surfaces for both the incident and exit surfaces, and by ensuring the medium's thickness increases with distance from the rotational symmetry axis, this invention achieves a larger divergence angle while meeting glare limits. This allows for increased lighting distance, reduced number of lights, and lower costs.

Description

[Technical field]

[0001] The invention relates to the technical field of lamps, and in particular to an LED emergency lighting lens that complies with European standards. [Background technology]

[0002] LED (light emitting diode), known as "green lighting", has attracted much attention. Compared with traditional light sources, LED has the characteristics of green environmental protection, small size, low power consumption and long life, which makes it very suitable for use as a light source for lamps. A complete lighting fixture must meet the requirements of lighting optics in the application, so the optical design of the light source becomes particularly important. For most LED light sources, if there is no light distribution design, the light emitted by the light source cannot be used reasonably and effectively, which does not meet the lighting requirements of various applications. The optical design of LED lighting fixtures includes primary light distribution and secondary light distribution. The process of packaging LED chips into LED light sources is defined as primary light distribution, which determines the light output angle, luminous flux, light intensity distribution and color temperature range of the light source chip. When LED light sources are applied to specific products, the distribution of light output efficiency, light intensity and color temperature of the entire system must also be designed, which is called secondary light distribution.

[0003] Emergency lighting is an important safety facility in modern public and industrial buildings. It is closely related to personal safety and building safety. When a fire or other disaster occurs in a building and the power supply is interrupted, emergency lighting plays an important role in personnel evacuation, fire rescue work, and the continued operation of important production and work or necessary operations.

[0004] European standard EN-1838 (EU emergency lighting standard) clearly stipulates the minimum illumination and uniformity of emergency lighting in different occasions, and has strict requirements on anti-glare in particular.

[0005] like Figure 1 As shown in the figure, the secondary light distribution of traditional emergency lighting only uses lens structures with typical angles (30°, 60°, 90°, 120°) and adopts quasi-Lambertian distribution light distribution, which has the disadvantages of unreasonable energy distribution such as small light-emitting angle and small irradiation range. Figure 2 As shown, the light-emitting angle of traditional emergency lighting is small, resulting in low illumination in the overlapping area between the two lamps, which easily leads to dark areas.

[0006] Therefore, it is necessary to provide a new LED emergency lighting lens that meets European standards to solve the above technical problems. [Summary of the invention]

[0007] The object of the present invention is to provide an LED emergency lighting lens which is glare-proof and has a larger divergence angle and complies with European standards, so as to solve the problems in the related art.

[0008] In order to achieve the above-mentioned purpose, the present invention provides an LED emergency lighting lens that complies with European standards, which includes a main body, the main body has a rotational symmetry axis, the main body includes a receiving cavity that can accommodate an LED light source, an incident surface and an exit surface that form a light inlet cavity, and a medium located between the incident surface and the exit surface, the incident surface and the exit surface are both free-form surfaces, and the incident surface and the exit surface are rotationally symmetric along the rotational symmetry axis, respectively, the thickness of the medium is the smallest at the rotational symmetry axis, and the thickness of the medium increases as the distance from the rotational symmetry axis increases.

[0009] More preferably, the receiving cavity is connected to the light inlet cavity.

[0010] More preferably, the main body further includes a fixing surface.

[0011] More preferably, the light a of the LED light source enters the medium from the incident surface, and then emits the light b from the exit surface, and the light b forms an arc θ with the rotational symmetry axis Z.

[0012] The intensity of light b satisfies the following relationship:

[0013] When 0<θ≤π / 3, I(θ)=I0*(-16.236*cos 4 θ+51.11*cos 3 θ-60.41*cos 2 θ+31.336*cosθ-A), A is a constant, 4.70≤A≤4.80;

[0014] When π / 3<θ<π / 2, I(θ)=I0*(28.558*cos 3 θ-11.634*cos 2 θ+1.4042*cosθ+B), B is a constant, 0.01≤B≤0.03,

[0015] I0 is the central light intensity of the LED light source located at the rotational symmetry axis Z after the light is emitted through the medium and the emission surface; the values ​​of A and B depend on the characteristics of the LED light source.

[0016] The technical effect of the present invention is as follows: by using free-form surfaces for both the incident surface and the exit surface, and the thickness of the medium increases as the distance from the rotational symmetry axis increases, thereby preventing glare and having a larger divergence angle, the lighting distance can be increased, the number of lighting can be reduced, and the cost can be reduced. In addition, the lens increases the effective irradiation area by reasonably reducing the proportion of light energy under the lamp.

Brief Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0018] Figure 1 It is the light intensity distribution diagram of the typical angles (30°, 60°, 90°, 120°) used by traditional emergency lighting;

[0019] Figure 2 It is a schematic diagram of overlapping lighting of two traditional emergency lightings;

[0020] Figure 3 is a cross-sectional view of an LED emergency lighting lens 100 of the present invention that complies with European standards;

[0021] Figure 4 It is a schematic diagram of an implementation of an LED emergency lighting lens 100 that complies with European standards of the present invention;

[0022] Figure 5 is a light intensity distribution diagram of an emergency lighting system using the present invention;

[0023] Figure 6 It is a schematic diagram of overlapping illumination of two emergency lighting systems using the present invention. [Specific implementation method]

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] like Figure 1 , Figure 2 As shown, traditional emergency lighting uses lenses with typical angles (30°, 60°, 90°, 120°), which have the disadvantages of unreasonable energy distribution such as small light-emitting angle and small illumination range. In addition, the illumination in the overlapping area between the two lamps is low, and dark areas are prone to occur.

[0026] like Figure 3 , Figure 4As shown, the present invention is an LED emergency lighting lens 100 that complies with the European standard, which includes a main body 1, and the main body 1 has a rotational symmetry axis Z. The main body 1 includes a receiving cavity 10 that can accommodate an LED light source 2, an incident surface 11 and an exit surface 12 that form a light inlet cavity 20, and a medium 13 located between the incident surface 11 and the exit surface 12. The incident surface 11 and the exit surface 12 are both free-form surfaces, and the incident surface 11 and the exit surface 12 are rotationally symmetric along the rotational symmetry axis Z. The light inlet cavity 20 is connected to the receiving cavity 10 and can accommodate light.

[0027] The medium 13 can be made of PMMA, PC or glass. The thickness D of the medium 13 is variable. The thickness of the medium 13 at the rotational symmetry axis Z is the minimum value D1. The thickness D of the medium 13 increases as the distance from the rotational symmetry axis increases. In the actual process, D1 can be as small as 0.8-1mm. Through such a design, the incident surface 11 and the exit surface 12 form a concave lens-like effect, thereby scattering the light and having a larger divergence angle.

[0028] The incident surface 11 is used to receive the light emitted by the LED light source 2 and control the angle at which the light from the LED light source 2 enters the medium 13 .

[0029] The main body 1 further comprises a fixing surface 14 , on which glue can be applied to fix the fixing surface 14 to the emergency lighting system.

[0030] like Figure 4 As shown, when the LED emergency lighting lens 100 of the present invention that complies with European standards is implemented, light a enters the medium 13 from the incident surface 11, and then emits light b from the exit surface 12. The light b forms an arc θ with the rotational symmetry axis Z.

[0031] The intensity of light b satisfies the following relationship:

[0032] When 0<θ≤π / 3, I(θ)=I0*(-16.236*cos 4 θ+51.11*cos 3 θ-60.41*cos 2 θ+31.336*cosθ-A), A is a constant, 4.70≤A≤4.80;

[0033] When π / 3<θ<π / 2, I(θ)=I0*(28.558*cos 3 θ-11.634*cos 2 θ+1.4042*cosθ+B), B is a constant, 0.01≤B≤0.03,

[0034] I0 is the central light intensity of the LED light source 2 located at the rotational symmetry axis Z after being emitted through the medium 13 and the emission surface 12; the values ​​of A and B depend on the characteristics of the LED light source.

[0035] like Figure 5 As shown, the light intensity distribution diagram of the emergency lighting system using the present invention shows that the light energy distribution is bat-wing distribution, symmetrical and uniform, the divergence angle can reach more than 130°, and the energy proportion directly below the center of the lamp is reduced, thereby greatly reducing glare and improving light utilization.

[0036] like Figure 6 As shown, a schematic diagram of overlapping lighting of two emergency lighting systems using the present invention is shown. After the divergence angle is increased to 130°, the overlapping area of ​​the two emergency lighting lamps is increased and the illumination is high, which is beneficial to increase the lighting distance and save costs.

[0037] The incident surface 11 and the exit surface 12 of the LED emergency lighting lens 100 that meets the European standard of the present invention are both free-form surfaces, and the thickness of the medium 13 increases as the distance from the rotational symmetry axis Z increases, so that under the premise of meeting the glare limit, it has a larger divergence angle, can increase the lighting distance, reduce the number of lighting, and reduce costs. The lens increases the effective irradiation area by reasonably reducing the proportion of light energy under the lamp, which is beneficial to improving uniformity and enhancing the user's visual experience. Under the same conditions, the total luminous flux of the lamp using the lens that meets the standard is 20%-30% lower than the luminous flux required by the existing technology, thereby reducing the power of the required emergency power supply and saving costs.

[0038] The LED emergency lighting lens 100 of the present invention that complies with European standards can be installed not only in an emergency lighting system but also in a common lighting system.

[0039] Finally, it should be noted that the above embodiments are only intended to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An LED emergency lighting lens that complies with European standards, comprising a main body having a rotational symmetry axis, characterized in that: The main body includes a receiving cavity for receiving an LED light source, an incident surface and an exit surface forming a light-inlet cavity, and a medium located between the incident surface and the exit surface, wherein the incident surface and the exit surface are both free-form surfaces, and the incident surface and the exit surface are rotationally symmetric along the rotational symmetry axis, respectively, the thickness of the medium at the rotational symmetry axis is the smallest, and the thickness of the medium increases as the distance from the rotational symmetry axis increases; The light a of the LED light source enters the medium from the incident surface, and then emits the light b from the exit surface. The light b forms an arc θ with the rotational symmetry axis, and the light intensity of the light b satisfies the following relationship: When 0 < θ ≤ π / 3, I(θ) = I 0* (-16.236 * cos 4 θ + 51.11 * cos 3 θ - 60.41 * cos 2 θ + 31.336 * cosθ - A), where A is a constant and 4.70 ≤ A ≤ 4.80; When π / 3 < θ < π / 2, I(θ) = I0 * (28.558 * cos 3 θ - 11.634 * cos 2 θ + 1.4042 * cosθ + B), where B is a constant and 0.01 ≤ B ≤ 0.03, I0 is the central light intensity of the LED light source located at the rotational symmetry axis after the light is emitted through the medium and the emission surface; the values ​​of A and B depend on the characteristics of the LED light source.

2. The LED emergency lighting lens that complies with European standards according to claim 1, characterized in that: The receiving cavity is communicated with the light inlet cavity.

3. The LED emergency lighting lens that complies with European standards according to claim 1, characterized in that: The main body also includes a fixing surface.

Images