DE29803105U1 - Infrared-free and ultraviolet-free lighting of unpackaged baked goods - Google Patents

Description

FRITZ-UDO FISCHER in 56244 Oetzingen-Sainerholz

Infrared-free and ultraviolet-free lighting of unpackaged baked goods

The innovation concerns lighting of baked goods that are normally presented in long counters and are free from invisible infrared and ultraviolet components.

It is known from German patent specification No. 3,323,166 that the effect of infrared heat radiation on slices of bread stacked in packets kills any mold spores and bacteria that may be present. However, when cakes are exposed to infrared radiation, there is a risk that artistic decorations made of chocolate flakes will melt and lose their shape.

While the effect of invisible infrared radiation (= heat radiation) on baked goods intended for human consumption is harmless even over longer periods of time, longer exposure to invisible ultraviolet radiation on such baked goods can be dangerous because, in extreme cases, it converts the protein present in all baked goods into toxins for human consumption.

In recognition of this fact, German patent specification No. 3,624,758 describes a refrigerated counter consisting of a furniture body with a product compartment for displaying foodstuffs and a structure which is provided with a transparent front panel on its front to prevent the ingress of warm air and for hygienic reasons. This front panel is provided with a coating produced by vapor deposition which only allows about 10 to 20 % of the incident intensity to pass through in the wavelength range between 300 and 400 πμη.

For the illumination of food, often presented to the public in a counter several meters long, daylight fluorescent tubes are mostly used, in which 2.55 % of the total radiation falls in the wavelength range of 300 to 400 μΩ; presented by GA Rutgers from the research department of NV KEMA, Arnhem/Netherlands, and printed in 'Proceedings of the FIRST INTERNATIONAL PHOTOBIOLOGICAL CONGRESS ¹ , (Amsterdam 1954), pages 293 to 296. In practical long-term applications of various fluorescent tubes

tubes it was also observed that the proportions of individual wavelength ranges in the total radiation 'change' with increasing burning time..'

From the 'Electronics Lexicon ^' , edited by Dr. Walter Baier in the 'Franckh'sche Verlagshandlung, 2nd edition, (Stuttgart 1982), page 124, a light-emitting diode grid for displaying numbers and letters is known, which is composed of light-emitting diodes; the commercially available diode grid, for example, provides a real alphanumeric display ^with 5x7 elements and a decimal point. The efficiency of the light-emitting diodes used here is, depending on the composition, between 0.4% (GaAsPj and 7% (GaP). Due to the relatively low efficiency, most of the power is converted into heat.

The innovation is based on the task of illuminating the baked goods presented in elongated counters free from ultraviolet and infrared radiation with as little loss as possible.

According to the innovation, this task is solved by placing several rectangular plates one behind the other above the baked goods to be presented, with numerous white light on one side at a beam angle of _

120° emitting light-emitting diodes, in a longitudinal direction of the ^ Jheke .'·.■

running rail are inserted. &Lgr;

In order to add colored light, in a further development of the innovation, a few colored light-emitting LEDs can be provided on the respective circuit board among the large number of white light-emitting LEDs. .;

In series production, a module and other parts of the wiring can be provided on the side of the circuit board opposite the light emission as a further development of the innovation.

Preferably, according to the innovation, for a counter about 1.25 m long, four boards can be inserted one after the other in the rail.

An embodiment of the lighting according to the innovation is shown in the drawing and is explained in more detail below. They show:

Figure 1 shows the arrangement of the lighting on a bakery counter and Figure 2 shows details of the lighting according to the innovation.

Figure 1 shows a service counter for unpackaged baked goods in elevation and partly in section: It can, but does not have to, have a cooled interior space 12" which is separated by a cold air flow 10" from the outer space 14" which is normally at about room temperature.

A projection 28" protrudes from the upper end of a transparent, partially glazed pane 22 over the possibly cooled interior space 12", which is closed off at the bottom by a plate 20" on which the baked goods to be presented lie, and partially forms a boundary of the interior space 12" at the top. ■.....'■■·,■.-.· ■ " . ■ · ■"■ ■ ■ ^: .. ' ■■·.. · - ■·.· ■ '■■;■

A rail 30 (only indicated in cross-section) is attached to the underside of the projections 28" Tst, the width of which is adapted to the width of a circuit board 32 shown in Figure 2, whereby the height of individual parts for establishing electrical connections is taken into account. With a minimum width of the service counter of approximately 1.25 m, four such circuit boards 32 are inserted one behind the other into the rail 30; they are electrically connected to one another and via a transformer to a power source (not shown). On the underside of the circuit board 32 (Figure 2) light-emitting diodes 34 are arranged in 20 rows and .5 columns, whereby a circuit element 35 protrudes upwards from the circuit board 32. .

A special feature of the embodiment according to Figure 2, which is intended for mass production of the lighting according to the innovation, consists in combining the module containing the electrical circuits and connections with the circuit board 32. A control circuit for the diodes 34 can be mounted on the upper broad side of the circuit board 32 opposite the diodes 34.

To make things clearer, here are some details about the objects used here:

Dimensions of board 32: 150 x 25 x 4 mm ■'.:■'.-

Wavelength spectrum of the diodes 34: 400 to 700 mp Illuminance of the board 32, measured at a distance of 0.5 m: 65 Tx Illuminance of four boards 32, inserted into the rail 30,

measured at a distance of 0.5 m: approx. 260 Ix supply with 24 V direct current Total power: 7 x 4 = 28 W

When connecting a conventional transformer, an electrolytic capacitor must be connected. . Color temperature of the diodes 34: 2900° K Service life of the diodes 34: 100,000 h Outside temperature range for operation of the diodes 34: -40° C to +40° C

Decrease in the illuminance of the diodes 34 after 10,000 hours of operation to . 97 to 98 % of the original value and after 100,000 hours to approx. 80 %

Claims (5)

Vs ·: P R E C T I O N C L A M E N T 1. Illumination of baked goods which are presented in normally elongated counters, free from the invisible infrared and ultraviolet components, characterized in that above the baked goods to be presented, several rectangular plates with numerous light-emitting diodes (34) emitting white light at a beam angle of 120° on one side are inserted one behind the other in a rail (30) running in the longitudinal direction of the counter. 2. Lighting according to claim 1, characterized in that for the addition of colored light on the respective circuit board (32), a few colored light-emitting light-emitting diodes are provided among the plurality of white light-emitting light-emitting diodes (34). 3. Lighting according to claim 1 or 2, characterized in that a module and further parts (35) of the wiring ^~j, are ^provided on the side of the circuit boards (32) opposite the radiation of the light. ■■' ■.'■■' ■ ' ■■■;·■■■ ,"i '.■■■ ■' '' "^, 4. Lighting according to one or more of the preceding claims, characterized in that for a 1.25 m long counter four plates (32) 5. Lighting according to claim 3, characterized in that a control circuit of the light-emitting diodes (34) is mounted on the upper broad side of the circuit board (32) opposite the light-emitting diodes (34).