DE102012216633A1 - Lighting concept for refrigerated cabinets - Google Patents

Abstract

The invention relates to a lighting concept, which allows a glare-free viewing of goods (4) in commercial refrigeration furniture (2) by the customer / viewer (8) with high and largely independent of the position color contrast with low energy consumption and high life of the light source (12) , For this purpose, according to the invention, at least one e3 plasma illuminant is used for illuminating the goods (4) in the interior of the refrigerated cabinet (2).

Description

Technical field / task:

The invention relates to a lighting concept for refrigerated cabinets under the premise of an attractive presentation of the presented goods for customers of all ages - taking into account the optimization for the age group 40+.

In addition, this concept should be based on the most efficient possible use of electrical energy - and should demonstrate the simplest possible manufacturability at reduced costs.

Analysis of previous situation / state of the art:

State of the art in the interior lighting / merchandise illumination of commercial refrigeration units was until 3-4 years ago the use of fluorescent tubes in conjunction with electronic ballasts (ECGs).

Since about 2008, the trend among manufacturers of commercial refrigeration appliances to use LEDs (LEDs). The main reason is the propagated energy saving and thus the reduced CO ₂ footprint per refrigerated cabinet. The industry wants to give a green coat and also jump on the ecological trend. However, the disadvantage is the insufficient lighting of the goods in the refrigerator and the falsified color reproduction.

• – Beleuchtung mittels Leuchtstoffröhre von hinten → leuchtet in Richtung Betrachter
• – Beleuchtung mittels LED von hinten → leuchtet in Richtung Betrachter
• – Beleuchtung mittels LED von hinten und vorn → leuchtet teilweise in Richtung Betrachter

In addition to the introductory information here is a brief summary:
So far, in commercially available refrigeration cabinets, especially in cabinets, the following versions can be found in the market:

• - Illumination by means of fluorescent tube from behind → shines in the direction of the observer
• - Illumination by means of LED from behind → shines in the direction of the observer
• - Illumination by means of LED from behind and in front → partially illuminates in the direction of the observer

• – Ausleuchtung der Ware nicht optimal, nicht attraktiv
• – Teilweise Blendung des Betrachters
• – Reflektionen auf den präsentierten Waren
• – Farbkontrast der Darstellung in hohem Masse NICHT-konstant über die Position
• – Verwendete Lichtfarben der im Kühlbereich einsetzbaren Lichtquellen reduzieren die gewünschte Farbwiedergabe der präsentierten Waren
• – „Schmuddeliger Anblick“ durch viele Interferenzen und Farbverschiebungen
• – Energieaufnahme bedingt durch technische Beschaffenheit und daraus ermöglichten Einbau unbefriedigend
• – „Unattraktive“ Darstellung der präsentierten Waren – aufgrund von Farbverschiebungen und Reflektionen
• – Unterschiedliche Markenerkennbarkeit durch unterschiedliche Farbwahrnehmung, bedingt durch die eingesetzte Lichtquelle und deren Positionierung und Verbau – ohne Rücksicht auf die unterschiedlichen „Seh-Bedürfnisse“ unterschiedlich alter Personen als Betrachter bzw. Kunden

The currently used solutions are considered as not optimal / in the following points:

• - Illumination of the goods not optimal, not attractive
• - Partial glare of the beholder
• - Reflections on the presented goods
• - Color contrast of the representation to a high degree NOT constant over the position
• - Used light colors of usable in the cooling range light sources reduce the desired color rendering of the presented goods
• - "grubby sight" due to many interferences and color shifts
• - Energy consumption due to technical condition and made possible from unsatisfactory installation
• - "Unattractive" representation of the presented goods - due to color shifts and reflections
• - Different brand recognition through different color perception, due to the light source used and their positioning and installation - regardless of the different "visual needs" different age persons as the viewer or customer

Object of the invention:

Lighting concept that avoids the disadvantages mentioned and instead allows glare-free viewing of goods in commercial refrigerators by the customer / viewer with high and largely independent of the viewing position color contrast with low energy consumption and long life of the bulb.

Inventive Approach:

Since many different studies now unambiguously understand how people's "vision needs" change with age, this information should also be taken into account in this approach, especially in Germany - and analogously in Europe - the number of older people increases significantly in society. According to current studies, we already have more than 40-year-old people today than under-40-year-old people. By the year 2020, there will be approximately 50% of under-50s and over-50s.

• – Reduzierte, spektral unterschiedlich veränderte Transmissivität des Sehapparates (Linse, Glaskörper etc.)
• – Deutliche Zunahme von Streuzentren im Sehapparat ( „Eintrübung“)
• – Verringerte Dynamik beim „Scharfstellen“ („Akkommodation / Accomodation“)
• – Verringerte Dynamik und längere Dauer bei der Helligkeits-Anpassung („Adaption“)

Reason enough to consider this circumstance in the desired solution. The relevant physiological-technical data of the human "visual apparatus", which should be considered with increasing age, are:

• - Reduced, differently spectrally altered transmissivity of the visual system (lens, vitreous, etc.)
• - Significant increase of scattering centers in the visual system ("cloudiness")
• - Reduced dynamics during "focusing"("accommodation")
• - Reduced dynamics and longer duration in the brightness adjustment ("adaptation")

• – Geringere Empfindlichkeit für kurzwelliges Licht → deutliche Reduktion des wahrnehmbaren Farbkontrastes
• – Geringere Gesamt-Transmissivität → mehr Licht für gleiche Sehaufgabe nötig
• – Wesentlich verstärkte Blendempfindlichkeit für Blendquellen insgesamt und Blendquellen aus gleicher Richtung wie das zu betrachtende Objekt
• – Geringere Sehschärfe bei geringerer Helligkeit durch schlechtere Akkommodation
• – Wesentlich verstärkte unterschiedliche Blendwirkungen durch zu geringe oder zu große Helligkeits-Kontraste (räumlich oder zeitlich aufgelöst)
• – Viele einzelne Lichtquellen (etwa bei LEDs) ergeben viele unterschiedliche Hell-Dunkelzonen und „Farbsäume“

With the directly derivable technical effects:

• - Lower sensitivity for short-wave light → Significant reduction in perceived color contrast
• - Lower overall transmissivity → more light needed for the same visual task
• - Significantly increased glare sensitivity for total blinding sources and blinding sources from the same direction as the object to be viewed
• - Lower visual acuity at lower brightness due to poorer accommodation
• - Significantly increased different glare effects due to low or too high brightness contrasts (spatially or temporally resolved)
• - Many individual light sources (such as LEDs) result in many different light-dark zones and "color fringes"

• – Gleichmäßige Ausleuchtung mit hoher Leuchtdichte
• – Gleichmäßig hohe Farbkontraste
• – Vermeidung von Blendquellen jeder Art, speziell aus der (Winkel-)Richtung des zu betrachtenden Objekts
• – Darstellung eines möglichst großen Farbraumes, um die Attraktivität der Darstellung für ALLE potentiellen Betrachter – aller Altersstufen – zu gewährleisten
• – Beleuchtung sollte normales Tageslicht bzw. Tageslicht-Verteilung nachbilden, um Bewertbarkeit zu gewährleisten

The requirements for the desired solution are:

• - Uniform illumination with high luminance
• - Uniformly high color contrasts
• - Avoidance of blinding sources of any kind, especially from the (angular) direction of the object to be viewed
• - Representation of the largest possible color space to ensure the attractiveness of the presentation for ALL potential viewers - of all ages
• - Lighting should emulate normal daylight or daylight distribution to ensure assessability

• – Hohe Energie-Effizienz (viel Licht für möglichst wenig elektrische Leistung)
• – Einfache Produzier- und Montierbarkeit
• – Hohe Lebensdauer des Leuchtmittels (möglichst solange wie das Gerät, in dem es eingebaut ist)
• – Dennoch einfache Austauchbarkeit
• – Einfache Skalierbarkeit für unterschiedliche Größen und Leistungen
• – Geringe Kosten in Herstellung, Betrieb und „End-of-Life“ (TCO – Total Cost of Ownership)

Additionally required:

• - High energy efficiency (lots of light for as little electrical power as possible)
• - Easy to produce and assemble
• - Long life of the bulb (as long as the device in which it is installed)
• - Yet easy to exchange
• - Easy scalability for different sizes and performances
• - Low costs in production, operation and end-of-life (TCO - Total Cost of Ownership)

• – Einseitige Lichteinkopplung von VORN → Lichtausbreitungsrichtung ist in Blickrichtung des Betrachters
• – Verbau der Lichtquelle im Volumen der Gerätewand – um jegliche Blendung sicher zu vermeiden
• – Lichtlenkung durch geeignete Gestaltung der Ausbreitungswinkel und der Reflektoren sowie Vermeidung von Interferenzen
• – Auswahl geeigneter Lichtquellen: Bevorzugt e³-Plasma-Lichtquellen, da klein und „ohne Schatten“, da lineare lambertische Strahler mit einem Durchmesser-zu-Längen-Quotienten von viel grösser als 1 zu 100, geeignet für die geforderten Kühl-Temperaturen und mittels relativ einfacher Optiken auf die geforderten Aufgaben anzupassen.

Concretization of the concept according to the invention:

• - One-sided light coupling of VORN → light propagation direction is in the direction of the viewer
• - Installation of the light source in the volume of the device wall - to avoid any glare safely
• - Light control by suitable design of the propagation angle and the reflectors and prevention of interference
• - Selection of suitable light sources: Preferably e ³ plasma light sources, since small and "without shadow" because linear Lambertian radiators with a diameter-to-length ratio of much greater than 1 to 100, suitable for the required cooling temperatures and adapt to the required tasks by means of relatively simple optics.

For example, an e3 plasma lamp from the company Global LightZ from the Wammes and Partner group of companies is planned as the light source. The abbreviation e3 (also: e ³ ) stands for Energy-Efficient Excitation = energy-efficient excitation.

The e3 lamps belong to the family of low-pressure discharge lamps. They typically consist of about 3 mm thin glass tubes - embedded in metal or glass ceramic body - that are machinable and therefore also deformable. Most of these bulbs are internally coated with doped ceramics. They also carry a so-called getter, an active material that serves to keep the inner volume of the e3 glass tubes clean for as long as possible. In addition, a special noble gas mixture with an internal pressure between about 2 mbar and 0.7 bar is used. The lamps can also contain powerful multi-band phosphors, which also make individual red, green and / or blue-emitting lamps possible. These are used to create or correct the desired light spectrum. By default, the e3 bulbs are operated with 24 V DC.

The complex operating principle of the e3 technology is based on the ionization of vaporized or gaseous particles for the controlled, temporarily stable cluster formation and is thus a more energy efficient and qualitatively improved development of the long known fluorescent tubes, which allows higher light yields with the same power consumption and lower volume. By suitable control of the processes, short-term stable clusters (exciplexes) of in each case two or more atoms or molecules are formed, which generate ultraviolet, visible and / or infrared light in the excited state. A suitable combination of these results in the desired light spectrum (the light color). In addition, the plasma processes still generate a small amount of extremely long-wave light, which is needed to control and control the entire system. Applying an electrical voltage creates an electric field that accelerates electrons within the glass tube - which inevitably leads to collisions, in which various precisely controlled quantum physical processes take place. The emitted photons are processed in the ceramic layer - by filtering and / or converting 3 to 6 eV high-energy photons into low-energy photons - leaving the glass tube as the desired (continuous) light spectrum. In order to achieve a stable ionization quite simply, noble gases are used as filling gas. Depending on the composition of the components involved, different types of clusters and participating elementary particles can be generated.

Luminous efficiencies of 50 to 100 lm / W are easily possible with e3 today. Depending on the version, e3 lamps can be operated at ambient temperatures of -35 C or less to well over +100 ° C. Unlike the always punctiform LED, the e3 tube radiates lambertically from any point of its line shape. This particularly important advantage in the present context will be explained in more detail below. The minimum CRI (Color Rendering Index) of the e3 tubes is> 80. Its good CRI retains e3 light at any light temperature. This is particularly advantageous because the latest generation of e3 tubes, the so-called "V-Light", is infinitely variable between 2,000 K and 10,000 K color temperature. The required control electronics are already integrated in the light source and can be addressed by means of buttons or other setting elements. Compared to current LED products, e3 tubes have three major practical advantages in terms of light color: First, all light temperatures can be realized with a single light source, while LEDs always require a mosaic of different colored diodes. Secondly, once the light temperature is set, e3 light sources remain permanently color-stable. Third, because e3 tubes emit very little heat to surrounding components, they can be installed without heat sinks, which also has a positive impact on the eco-balance and is particularly advantageous for use in refrigerated cabinets.

The e3 tubes themselves meet all EU standards for energy efficiency and low emissions and are 100% recyclable. Due to their relatively few component design, less energy has to be used for production and recycling than for other lamps.

• – Mechanischer Verbau in der Geräte-Vorderwand – am oberen Ende bei Truhen, am vorderen Ende bei Schränken oder entsprechend geeigneter Form bei anderen Kühlmöbeln
• – Optische Konditionierung mittels geeigneter Optiken bestehend aus Reflektor und vorzugweise Linsen in Lentikular-Struktur

In accordance with the optical and mechanical adaptation described above, the following installation concept is provided in summary:

• - Mechanical installation in the front of the appliance - at the upper end in chests, at the front end in cabinets or according to suitable shape in other refrigerated cabinets
• - Optical conditioning by means of suitable optics consisting of reflector and preferably lenses in lenticular structure

Preferred embodiment / advantages:

Thus, a solution can be found for the task described above - in 1 exemplified by a freezer.

Here is a cross section through a freezer as an example of a refrigerated cabinet 2 with goods stored therein for cooling 4 and with optional transparent cover 6 shown. The viewer 8th is in front of the refrigerator 2 and looks in a viewing angle area 10 on the goods 4 in the interior, which of the bulbs 12 be illuminated. At the bulb 12 it is a rod-shaped, elongated e ³ -plasma-light, which is parallel to the front upper longitudinal edge 14 of the refrigerator 2 , something to the interior of the refrigerator 2 arranged offset. The partly direct and partly by reflection - about the reflectors 16 or on other sections of the inner wall - on the goods 4 Hitting light rays are represented by arrows (the reflection on the goods 4 was omitted to simplify the drawing).

In a variant, not shown, the light source 12 also outside the fridge 2 arranged or not structurally integrated (external lighting).

The light extraction is advantageously divided into a vertically narrow collimated segment (depending on the depth of the device, for example, 25 degrees to the horizontal -5 / + 10 degrees) and a vertically low-collimated segment (about 130 degrees +/- 25 degrees).

This is realized by means of the described optics of lenticular lens structure and suitable reflector - similar to a "two-zone glasses".

In the horizontal direction, the light propagation of the selected e ³ plasma light sources is NOT changed, because the intrinsically predetermined characteristic - light rays are emitted from each point of the linear light source in EVERY solid angle outside the very thin light source - results in a very uniform, glare- and largely shadow-free illumination.

An essential advantage of the e3 plasma lamps is that they are elongated, quasi-line-shaped light emitters with - to a very good approximation - Lambertian radiation characteristics.

Light sources which have no directional dependence of the radiation density are known as diffuse radiators or lambertian radiators. They emit the same radiation density in all directions. Due to a perspective effect, the radiation power or intensity output by them in a specific direction or a specific solid angle range only varies with the cosine of the emission angle relative to the surface normal of the light-emitting surface element (Lambert's cosine law). Accordingly, in the polar coordinate diagram there is a circular intensity curve for each possible orientation (ie, each possible azimuth angle) of the surface normal Measuring plane. If this applies to every surface element of a light source, in this case for each line element of the line emitter, then there is a Lambert emitter whose diffused light is distributed largely without glare in the space and causes only a small amount of shadow in the objects present in the ray path. The chosen vertical angular spread and the positioning at the front / top edge of the device ensures that the light that does not hit directly into the interior of the device meets the glass surface covering the device volume (door / cover) only at very shallow angles. and the light rays are therefore largely reflected in the transition from a medium having a lower refractive index into a medium having a higher refractive index according to physical laws (the stronger, the flatter the angle) and therefore help to evenly illuminate the presented goods in the interior.

To reinforce this purpose, the opposite wall of the light source is mechanically / optically formed so that it is reflective on the one hand and the second reflected the direction of the reflected light rays back into the interior of the device that there presented ideally to the present goods ever Single product forms around each individual product as uniform as possible semi-cylindrical luminous intensity distribution.

In addition, the light source, the significantly reduced interference, the optical design of the lens and reflector, and the described positioning of the light source including all indirect (glass, presented goods, fixtures, etc.) and immediate (default) reflectors achieved that the color representation DRAMATICALLY better - and thus the attractiveness of the presented goods is increasing - for all observers.

For older observers, there is the additional advantage that the presented goods in the device of the same present product looks significantly more similar under daylight - and thus more reliably recognized.

The same applies to the topic of glare: Since in the presented approach the light source radiates in the viewing direction and all direct and all known indirect reflectors (eg glass lid, glass door) can emit light only in the viewing direction or only in the internal volume of the refrigerator, is a direct , physiological, adaptation or relative glare excluded.

• – Durch Einsatz von Lichtquellen auf nur einer Seite des Kühlmöbels ist die Montage und Verkabelung deutlich einfacher und günstiger
• – Auch ist dadurch die Kostenstruktur (gleiche Stückzahlen vorausgesetzt) günstiger
• – Auch aus Umweltaspekten rechnet sich diese Lösung, da hier weniger Ressourcen verbraucht werden
• – Es konnte auch nachgewiesen werden, dass für gleiche Leuchtdichten auf den präsentierten Waren maximal gleiche, meist sogar deutliche geringere elektrische Leistung als mit bisherigen Lösungsansätzen notwendig ist
• – Durch die massiv verbesserte Farbdarstellung kann nun auf unterschiedliche Leuchtmittelversionen je nach Anwendungszweck verzichtet werden

It has also been demonstrated that the commercial aspects of this solution are also feasible:

• - By using light sources on only one side of the cabinet, the installation and wiring is much easier and cheaper
• - Also, the cost structure (assuming the same quantities) cheaper
• - This solution also pays off for environmental reasons, since fewer resources are used here
• - It could also be proven that for the same luminance on the presented goods a maximum of the same, usually even significantly lower electrical output is necessary than with previous solutions
• - Due to the massively improved color display can now be dispensed with different light sources versions depending on the application

• 1. Modulare Kühlmöbel (offen oder geschlossen, in horizontaler oder vertikaler Bauform) für den Anschluss an eine externe Kälteanlage. Das sind z.B. die Kühlregale im Supermarkt für Molkereiprodukte oder Selbstbedienungstheken für Wurst / Käse, aber auch Bedienungstheken für Wurst / Käse sowie die Tiefkühlinseln, aus denen Tiefkühlpizzen und -gemüse verkauft werden.
• 2. Steckerfertige Kühlmöbel (auch „self-contained“ oder „plug-in“ genannt) im Pluskühl- und Minuskühlbereich, offen und geschlossen, in horizontaler und vertikaler Bauform. Also sowohl der Getränkekühlschrank in der Eckkneipe als auch die Tiefkühlinseln in Supermärkten, aus denen Tiefkühlkost verkauft wird sowie Eiskremtruhen in jedem Kiosk.

The inventive concept is summarized in particular provided for

• 1. Modular refrigerated cabinets (open or closed, in horizontal or vertical design) for connection to an external refrigeration system. These include, for example, the refrigerated shelves in the supermarket for dairy products or self-service counters for sausage / cheese, but also serving counters for sausage / cheese and the frozen islands from which frozen pizzas and vegetables are sold.
• 2. Plug-in refrigeration units (also called "self-contained" or "plug-in") in the plus and minus refrigerated area, open and closed, in horizontal and vertical design. So both the drinks fridge in the Eckkneipe and the frozen islands in supermarkets, from which frozen food is sold and ice cream chests in every kiosk.

Measurement results:

• 1. Leuchtstoffröhre (rote Messpunkte)
• 2. LED-Beleuchtung (gelbe Messpunkte)
• 3. e3-Plasmaleuchte (blaue Messpunkte)

dargestellt (in der Ecke oben rechts befindet sich ein Referenzfarbmuster). Man erkennt deutlich, dass die erkennbare Farbpalette für die e3-Plasmabeleuchtung wesentlich größer ist als für die aus dem Stand der Technik bekannten Beleuchtungskonzepte. In 2 is for a freezer according to 1 the measured color gamut, that is the amount of all the colors perceived by the viewer in the CIE chromaticity diagram for the three different illuminants

• 1. Fluorescent tube (red measuring points)
• 2. LED lighting (yellow measuring points)
• 3. e3 plasma light (blue measuring points)

(there is a reference color pattern in the upper right corner). It can be clearly seen that the recognizable color palette for the e3 plasma illumination is substantially larger than for the lighting concepts known from the prior art.

• – Bei der Warenbeleuchtung durch Leuchtstoffröhren (5) sind nur die direkten Reflektionen entsprechend hell. Damit liegt eine starke Direkt-Blendung vor.
• – Bei der Warenbeleuchtung durch LEDs (4) existiert eine starke Ausprägung von „Spitzlichtern“ (Peak-Helligkeiten) und damit eine starke physiologische Blendung.
• – Bei der Warenbeleuchtung durch e3-Plasmaleuchten (3) hingegen ist eine Konzentration der Leuchtdichte auf die Waren realisiert. Der wahrgenommene Kontrast (perceived contrast) ist erhöht, während Blendungen vermieden sind.

In 3 to 5 in reverse order of the above list, the measured luminance over the display surface is shown as a measure of glare when considering the display of the goods - in all three cases the same order in the same device. The viewing direction is indicated by the arrow. The same color in the diagrams corresponds to the same luminance. The higher the luminance peaks applied in z-direction relative to the background brightness, the greater the glare. One recognizes the following:

• - In the case of goods lighting by fluorescent tubes ( 5 ), only the direct reflections are correspondingly bright. This results in a strong direct glare.
• - In the case of goods lighting by LEDs ( 4 ) there is a strong expression of "highlights" (peak brightnesses) and thus a strong physiological glare.
• - In the case of goods lighting by e3 plasma lamps ( 3 ), however, a concentration of luminance on the goods is realized. The perceived contrast is increased while glare is avoided.

The electrical power used was for the LED lighting ( 4 ) normalized to 100%. For the lighting of goods by fluorescent tubes ( 5 ), 130% were measured, which is within the expected range. Surprisingly, for the e3 lighting ( 3 ) only 50% needed. This means, in particular, a significantly lower waste heat, which must be dissipated by the cooling units.

LIST OF REFERENCE NUMBERS

2

refrigeration cabinets

4

Would

6

cover

8th

observer

10

Viewing angle

12

Lamp

14

longitudinal edge

16

reflector

Claims (2)

Refrigerated furniture ( 2 ), in particular freezer, refrigerated counter, refrigerated display case, cooling table, refrigerator or the like, with an integrated light source ( 12 ) for illuminating in the refrigerator ( 2 ) stored goods ( 4 ), characterized in that the lighting means ( 12 ) is an e3 plasma lamp. Use of an e3 plasma lamp for illuminating goods stored for refrigeration ( 4 ) in a refrigerated cabinet ( 2 ).

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