AU2020104402A4

AU2020104402A4 - High-efficiency two-tone dimming led street lamp based on mesopic vision

Info

Publication number: AU2020104402A4
Application number: AU2020104402A
Authority: AU
Inventors: Yunwang Ge; Chao GUO; Yali Li; Yafei REN; Bo Wang
Original assignee: Luoyang Institute of Science and Technology
Current assignee: Luoyang Institute of Science and Technology
Priority date: 2020-04-17
Filing date: 2020-12-30
Publication date: 2021-03-18
Anticipated expiration: 2028-12-30
Also published as: CN111396787A; CN111396787B

Abstract

The invention relates to the technical field of mesopic vision, and discloses a high-efficiency two-tone dimming LED street lamp based on mesopic vision, wherein a plurality of white LEDs and a plurality of cyan LEDs are mixed in a ratio of 5:1 to 10:1, and the dominant wavelength of the cyan LED is 500 nm-510 nm. The color temperature range of the white LED is 3000K-4000K, and the color rendering index is 65-80. The lumen output ratio of the white LED and the cyan LED is 4:1-8:1. The invention provides a high-efficiency two-tone dimming LED street lamp based on mesopic vision. On the basis of providing pedestrians with the same brightness at night, the efficiency of the street lamp is greatly improved. 1 DRAWINGS iS 507nm 555nm I~ - Phtpic ......... .....coropic 0,8 0.6 0A | 0A 350 450 550 650 750 Wavelength(nmr) FIG.1 1.2 White 1.E 1 ----- Cyan LED 0.8 - Combination 0.6 i - 0.2 380 430 480 530 580 G30 680 7-30 780 Wavelength~nm) FIG. 2 1

Description

DRAWINGS

iS

507nm 555nm I~- Phtpic

......... ..... coropic 0,8

0.6

0A |

0A

350 450 550 650 750 Wavelength(nmr)

FIG.1

1.2

White 1.E 1 ----- Cyan LED

0.8 - Combination

0.6 i

-

0.2

380 430 480 530 580 G30 680 7-30 780 Wavelength~nm)

FIG. 2

DESCRIPTION HIGH-EFFICIENCY TWO-TONE DIMMING LED STREET LAMP BASED ON MESOPIC VISION FIELD OF THE INVENTION

[0001] The invention relates to the technical field of mesopic vision, in particular to a

high-efficiency two-tone dimming LED street lamp based on mesopic vision.

BACKGROUND OF THE RELATED ART

[0002] The two types of cone cells and columnar cells contained in the human eye play a role

in photopic and scotopic vision conditions, respectively. The different spectral response

characteristics of the two cells determine the spectral visual efficiency curve of human eyes

under the two conditions. It can be seen from the figure below that the peak of the scotopic

light effect curve is around 507 nm, and the peak of the photopic light effect curve is at 555

nm. The usual optical instruments are measured under photopic conditions, while street lamps

are used for night lighting, and their brightness distribution should fall within the mesopic

vision range (0.01-3cd/cm 2). Therefore, the current claimed brightness of street lamps only

reflects the performance under photopic conditions, and cannot truly reflect the lighting

needs of street lamps for human eyes at night.

[0003] In order to more accurately quantify the application performance of street lamps in the

actual environment at night, the industry usually uses the s/p ratio to reflect the difference in

light and dark vision conditions. When the s/p ratio is equal to 1, it indicates that the

brightness of the street lamp in a bright and dark environment is equivalent to the human eye;

when the s/p ratio is greater than 1, it indicates that the brightness of the street lamp to the

human eye at night is greater than the measured value during the day. Taking a 3000K sodium

lamp and an LED street lamp as an example, the s/p ratio of the sodium lamp is only 0.93,

while that of the LED street lamp is 1.49, which indicates that under the pure dark vision

condition, the lumen of the sodium lamp need to be 1.5 times that of the LED street lamp to

achieve the same level of illumination. Although CIE (Commission Internationale de

lEclairage) experts have not given an accurate mesopic visual function curve so far, that is to

DESCRIPTION say, although the illuminance of LED street lights at night has been improved, it has not

reached the level of multiples of s/p ratio. In order to be close to practical applications,

currently the m/p ratio is used as the metric, that is, the ratio of mesopic vision and photopic

vision. The calculation formula for the mesopic vision m is: m=(s+p)/2.

SUMMARY OF THE INVENTION

[0004] The invention provides a high-efficiency two-tone dimming LED street lamp based on

mesopic vision. On the basis of providing pedestrians with the same brightness at night, the

efficiency of the street lamp is greatly improved.

[0005] The invention provides a high-efficiency two-tone dimming LED street lamp based on

mesopic vision, wherein a plurality of white LEDs and a plurality of cyan LEDs are mixed in

a ratio of 5:1-10:1, and the dominant wavelength of the cyan LED is 500 nm-510 nm.

[0006] The color temperature range of the white LED is 3000K-4000K, and the color

rendering index is 65-80.

[0007] The lumen output ratio of the white LED and the cyan LED is 4:1-8:1.

[0008] The lumen output ratio of the white LED and the cyan LED is 6:1.

[0009] Compared with prior art, the advantageous effects of the invention are:

[0010] In the invention, a plurality of cyan LEDs with a dominant wavelength of 500 nm-510

nm are added to a plurality of white LEDs and mixed in a ratio of 5:1-10:1. Based on

mesopic vision, the efficiency of the street lamp is greatly improved on the basis of providing

pedestrians with the same brightness at night.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a photopic and scotopic vision function curve of human eyes provided by the

embodiment of the invention.

[0012] FIG. 2 is a white LED spectrum, a cyan LED spectrum, and a spectrum curve diagram

after mixing the two according to the embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A specific embodiment of the invention will be described in detail hereinafter with

reference to FIG. 1-2, but it should be understood that the protection scope of the invention is

not limited by the specific embodiments.

DESCRIPTION

[0014] Table 1 below shows that after the LED with a color temperature of 3000K and the

cyan (main wavelength of 500-510 nm) LED are mixed at a lumen output ratio of 6:1, the

color temperature CCT is increased to 4000K, and the m/p ratio has been increased from 1.11

to 1.37, compared to the m/p ration of 1.3 that directly uses the 4000K white LED. When this

kind of street lamp is used in night lighting applications, its brightness is higher than that of

directly using the 4000K white LED, which improves the color rendering index of the lamp

at the same time, and improves the ability to reflect the original color of actual objects at

night.

Table 1 Performance Comparison Table of Ordinary LED Street Lamps and Cyan/White LED

Two-Tone Mixed Street Lamps

LED Ordinary Street LED Two-Tone Mixed Street

Lamps Lamps

Light Source LED Color 3000K+cyan light (lumen output 3000K 4000K Temperature ratio is 6:1)

Street Lamp Color 3000K 4000K 4000K Temperature CCT

Street Lamp Color 71 75 83 Rendering Index CRI

Photopic Vision Output 2000 2000 2000 (lm) Scotopic Vision Output 2440 3180 3460 (lm) Mesopic Vision Output 2220 2590 2730 (lm)

Scotopic/ Photopic Vision 1.22 1.59 1.73 Ratio s/p ratio

Mesopic/ Photopic Vision 1.11 1.30 1.37 Ratio m/p ratio

[0015] The comparative data in Table 1 shows that the efficiency of the cyan and white

DESCRIPTION two-tone mixed LED street lamp is significantly higher than that of the ordinary LED street

lamp regardless of the scotopic vision condition or the mesopic vision condition.

[0016] The invention includes two kinds of LED light sources, white LEDs and cyan LEDs

with a dominant wavelength of 500-510 nm. Set the lumen output ratio of the two in the

range of 5:1-9:1 to obtain a light source array after mixing, and the spectrum emitted by this

mixed light source array has a much higher m/p ratio than that of traditional white LED street

lamps. That is to say, the actual brightness of the street lamp with this LED array as the light

source at night is higher than the reading in the test equipment. With the further increase of

cyan light content, the value of the m/p ratio will increase accordingly.

[0017] FIG. 1 shows the photopic and scotopic vision function curve of human eyes. It can be

seen that the human eye is most sensitive to light with a spectrum of about 507 nm in a dark

environment, while is most sensitive to light with a spectrum of 555 nm in a bright

environment. That is to say, for the same input energy under different light and dark

conditions, the brightness of the lamp is different to human eyes. For ordinary LED street

lamps, the luminous spectrum is shown in the white LED spectrum curve in FIG. 2, with a

band around of 507-531 nm, which is the main application environment of street lamps at

night. Under scotopic and mesopic vision conditions, the proportion of light radiation energy

is very small, and the effect on human eyes under dark conditions will not be obvious. After

mixing the cyan LED, i.e., the spectrum curve of the cyan LED in FIG. 2, the energy

proportion of the spectrum in this band is greatly increased, which improves the sensitivity of

human eyes under scotopic and mesopic vision conditions, and increases the application

power of the street lamps accordingly.

[0018] What has been disclosed hereinabove are only a few specific embodiments of the

invention, but the embodiments of the invention are not limited thereto. Any modifications

that may be thought of by those skilled in the art shall all fall within the protection scope of

the invention.

Claims

CLAIMS 1. A high-efficiency two-tone dimming LED street lamp based on mesopic vision,

wherein a plurality of white LEDs and a plurality of cyan LEDs are mixed in a ratio of

:1-10:1, and the dominant wavelength of the cyan LED is 500 nm-510 nm.
2. The high-efficiency two-tone dimming LED street lamp based on mesopic vision

according to claim 1, wherein the color temperature range of the white LED is 3000K-4000K,

and the color rendering index is 65-80.
3. The high-efficiency two-tone dimming LED street lamp based on mesopic vision

according to claim 1, wherein the lumen output ratio of the white LED and the cyan LED is

4:1-8:1.
4. The high-efficiency two-tone dimming LED street lamp based on mesopic vision

according to claim 1, wherein the lumen output ratio of the white LED and the cyan LED is

6:1.

D R AW I N G S Dec 2020 2020104402

FIG. 1

FIG. 2