DE19919638A1 - Arrangement for displaying prices and article identifiers on goods carriers for stores and warehouses - Google Patents

Abstract

The arrangement has display devices attached to the carriers in electronic labels, each comprising a graphical display device with a fluidic system with bistable contrast-generating image cells. The arrangement has display devices with a fluidic system that has parallel, mutually independent micro-channels arranged along an information row. Each micro-channel has a visible region and a micro-mixer on the input side with two input lines for different contrast-generating fluids. Each input line is connected to the mixer via a micro-pump. There is a common flow meter for all visible channels. All input lines and all output lines are connected to a common separator as a reservoir for both fluid systems.

Description

The invention relates to a device for displaying prices and item names drawings and similar information on product carriers in department stores and warehouses with the help of electronic display devices attached to the product carriers labels that are functionally connected to an external control center are that the control center address a single electronic label and May transmit information about this electronic label.

Printed labels for labeling goods with prices and similar information are subject to change at regular intervals. The manual effort is considerable, and so electronic price display devices have been proposed and known, the display devices use the price and the like View information that can be changed by a control center.

It is necessary to transfer information from a control center to the respective electronic label, and a power supply for the display device and a control unit in the electronic label. After first devices where the information from a control center and the Power supply via cable connections and conductive tracks to the electronic label ((GB 1544005, GB 2083673) is described in the patent US 5313569 as an electronic label an independent puncture unit proposed that a display device, a control unit and power supply contains and is directly or indirectly connected to the control center.  

The information on the article number and article price are included (see also EP 0228377 ) stored in changeable registers in the electronic label, the Content by a micropro forming the control unit in the electronic label compared with the information received from the control center is also changed and displayed. The address of the label is included determined by the article number stored in a register and can thus can also be changed.

All of these devices require a continuous supply of in the operating state Energy to ensure the display, whether in the form of a built-in battery, a solar cell or a wired power supply. This creates for them Devices significant disadvantages.

For example, it is not for the operator of such a pricing device acceptable batteries for the life of the electronic label exchange. The available area of the electronic labels limits the size of solar cells. Wired power supplies limit flexibility considerably. The execution of the electronic label as an independent function unit with its own power supply therefore limits the practical execution of the Display device on an LCD type, although numerical values about item prices and quantities are displayed, but in the known versions to text Representations because of the required energy requirement of the display device must be waived. The consequence of this is a correspondingly high installation effort of the price labeling device, the high level of care of the operator requires personnel. Finally, the electronic label must be logical Address, which is derived from the article number, near the relevant one Article are arranged. This arrangement must also apply to the potential buyer of the article should be so clear that no confusion is possible.

This unambiguous relationship of the label to the product concerned is without further Aids only possible with clearly structured goods carriers, such as shelves. In order for the customer to have a clear relationship between item and to produce electronic labels on the whole variety of product carriers Often, additional paper stickers affixed to the electronic label affix the Wear the names of the associated items. This measure increases the installation continued to spend.  

In WO 99/04532 an electronic label is described, which has a graphic display device, the specificity of which is energetically bistable contrast-generating image cells. There is a receiving one in the electronic label Communication module available, which is a ROM with a permanently set unique Label identification number with the address signals of the external control center contains. If there is a match, the image content is sent to the graphic via a gate Display device forwarded. A mobile data acquisition device with read head for To set up the device, barcodes detect one arranged on the goods carrier Identification number and the article number arranged on the article, the purpose are carried out in the form of barcodes and transmits this information to the external control center.

The graphic display device is designed as a fluidic system by using in line with the picture content at least two, differing in contrast Fluids are required in a meandering channel, this meander out vertical or horizontal, parallel viewing channels and the viewing channels connecting overflow channels. Will a change in the image content the old image content is replaced by the new one in the manner of a shift register Image content pushed out and pushed out. It is to close the circuit necessary to separate the two fluids from each other and separate storage containers feed. For this purpose, a so-called separator is used, in which the separation by Utilization of different physical properties, e.g. B. the surfaces tension or by different weights. Stand at its exits the segregated fluids are again available to the respective micropumps. So that is the fluidic system closed.

In another embodiment of the invention, a magnetically conductive fluid used and the segregation is carried out by the action of a magnetic field.

The required precision in the metering of the two fluids by the micropumps is achieved in that a measuring channel is provided, which the flow rate of the Fluids determined by optically acting sensors and with the result the Controls the delivery rate of the micropumps. The overall control of the pump power is designed as a phase-locked loop, with those transmitted by the control center Image content with constant intervals of contrast are introduced which lead to Pre-synchronization of the pump power with the transfer rate of the image content are seen. The entire fluidic system is made of 100-oriented in a basic body Silicon wafers introduced by anisotropic etching. This results in a V-shape  Channels with precise, reproducible cross sections. The basic body with its Channels are covered by an anodically bonded glass or silicon top layer covered.

The two micropumps have rectangular pumping chambers. The cover layer acts as a membrane together with a glued silicon wafer forms a bimorph.

Taking advantage of different dynamic flow resistances in the inlet and Drainage to the pumping chamber occurs when the piezo is actuated in a sawtooth manner disks a resulting volume flow of the fluid. Other sensors are in the Drains from the pumping chamber to the mixer are provided to prevent a backflow of Fluid into the pump, which is inactive for image formation, by countermeasures prevent. The entire fluidic system is filled through a special filling opening, which expediently in the mixer for the different fluid flows flows into.

In one embodiment, the fluidic system is made of plastic in a base body brought in. The corresponding microstructures of the pumping chambers and meandering shaped channels are incorporated into a plastic board. The overflow channels of the meander as well as the supply and discharge lines to the mixer and measuring channel can thus be rounded off. This results in lower flow resistances for the Fluid. But there are also others for the pumping chambers and other channels Possibilities for geometric design.

The disadvantage of this arrangement is, however, that changes the ambient temperature or in the event of temperature fluctuations Extends visible channels fluid and the linear expansion a shift of the fluid and thus the interfaces or the color transitions. The yourself due to the expansion of the fluid, undesirable misalignment of the limit Surfaces of the fluids due to the shift in the color transitions must be controlled be counteracted. Otherwise this offset increases in the neighboring and in the other view channels next to each other due to the changing flow direction other channels and ultimately leads to contour deviations of the set Image information. The arrangement of a metal screen for contrast was only partially possible contribute to improvement. The effort to compensate for the temperature error is  not insignificant and requires synchronous control even during the idle phase the ad.

The adjustment of the information lines was carried out in this display type Time intervals with auxiliary color changes that are to remain invisible at the Representation of information located in the invisible channel transitions have to.

Furthermore, the meandering arrangement of a fluid channel with a large number overall of channel transitions represents a very large resistance that the micro pump at the entrance of the meander with their pumping power. The Pump power is therefore to be chosen to be large enough to control the fluid to set the pumps in motion. On the other hand, the pump power is due to the Limited microstructure of the pumps.

The invention is therefore based on the object of an improved device for View multiline information about prices and item names To develop product carriers that also display a fluidic system energetically bistable contrast-producing image cells, which is in microstructure located on a common support and their display area from channels for one flowing contrasting fluid exists, with low flow resistance requires less pumping power for the fluids and changes in the environment temperature or temperature fluctuations in a simple manner even during the Rest phase compensated.

According to the invention, the device is solved by a structure of microchannels, which consists of individual parallel channels and each has a separate fluid inlet and output, each channel having a pump system, a mixer and for each type of fluid a measuring channel synchronizing the fluid flow for flow measurement assigned. The outputs of all view channels lead via a collecting line a common storage or separator.

Because of a favorable relationship between channel length and channel cross cut results in a low flow resistance and requires of those used  bidirectional dynamic micropumps have a correspondingly low delivery rate. The measuring channel provided for each fluid in the inlet leads to a constant speed measurement and acts continuously on the phase control loop of the pump control on. The individual picture cells in the different channels can thus continuously be synchronized.

Errors caused by length offset in the expansion of the fluid at temperature Changes and temperature fluctuations occur in size and Direction equally in all view channels and thus remain without adverse effects Impact, because due to the same flow direction in all channels for everyone Image cells sets an equally large offset. The error remains undetected.

Another feature of the solution is the execution of the microstructure in a plastic carrier so that the channels in their geometry, for. B. the Kanalzu- and -Procedures or the channel cross-section, adapted to optimal flow conditions can be.

The two inputs and its output are in the mixer for each viewing channel Cross-section constricting or constricting. This ensures that this Place a resistance and the fluid is stopped. Because of the surfaces As a result of the tightening of the fluid, a meniscus occurs at this constriction as associated micropump at this inlet is inactive. When the micro is activated pump in the second inlet for the second fluid, a free flow is thus possible. With This narrowing of the inlet channels becomes picture cells and ensures safe color changes.

The idea on which the invention is based is described in the description below using an exemplary embodiment which is shown in more detail in the drawing, explained.

It shows:

Figure 1 is a schematic diagram of a known label with two fluids.

FIG. 2 shows the flow principle and circuit of the fluid according to FIG. 1;

Fig. 3 is a representation of the boundary surfaces of picture cells in a meander as shown in FIG. 2;

Fig. 4 basic principle of a fluid channel of the inventive device;

FIG. 4a shows detail A according to Figure 4 - mixer.

. FIG. 4b shows detail B according to Fig 4 - cross-section of the transition at the end of each view channel;

Figure 5 is a top view of the structure of the channel body of the device;

Fig. 6 is an equivalent circuit diagram for the control of the individual pumps for the viewing channels;

Fig. 7 is a cross section through the label;

Fig. 8 is an enlarged cross-sectional view of the arrangement of a pump on the channel body acc. Fig. 7.

In Fig. 1 a known electronic label is shown with a fluidics system in a silicon wafer. The channel system consists of a meander, ie all view channels ( 5 ) are connected to overflow channels ( 7 ) to form a continuous channel. The meander has only one inlet ( 4 ) and only one outlet ( 9 ). In the event of a change, an image cell ( 6 ) must therefore be pushed through all viewing channels ( 5 ) and overflow channels ( 7 ). A mixer ( 2 ) is arranged in front of the inlet ( 4 ) in the meander, in which the two different contrast-generating fluids ( 1 ; 3 ) are brought together alternately in accordance with the image content to be generated. The outlet from the meander is led via the channel ( 9 ) to the input of a separator ( 10 ) as a genius storage reservoir for both fluids ( 1 ; 3 ). The outputs from the separator ( 10 ) in turn lead to the two channel inputs ( 1 ; 3 ) on the mixer ( 2 ). The device is energetically stable in that it is a closed channel arrangement in which when the micropumps P1 and P2 ( FIG. 2) are switched off, pressure equalization takes place and further movement of the fluids 1 and 3 is not possible. The entire meander represents a flow resistance, which must be overcome by the pumps P1 and P2 in order to push the fluids in the meander. The pumping capacity must be chosen accordingly. Since the speed of the fluid also does not coincide with the target speed at the beginning of a renewal process for the image content, there is a phase difference in the synchronization contrast change determined on a sensor. This difference is obtained in a phase comparator with the signal determined by the sensor. In order to synchronize the image cells ( 6 ), further synchronization contrast changes are introduced into the meander at regular intervals between the contrast changes carrying the image content, which changes must remain invisible after the completion of an information change and are therefore inserted into the covered channel transitions. The smallest distance between these synchronization contrast changes is defined by the length of the viewing channel ( 5 ) or by the distance from two overflow channels ( 7 ) and is therefore very large.

As shown in FIG. 2, 4 sensors are required for the synchronization of the fluid control, two sensors of which are required on the mixer.

Changes in the ambient temperature or temperature fluctuations mean that the fluids change their volume and expand. This expansion also results in a change in the length of the individual picture cells and their spacings, and the shift influences the contrast of an entire picture information ( FIG. 1). The relative error is small at first. However, it increases from sight channel ( 5 ) to sight channel ( 5 ), since the direction of flow of adjacent sight channels ( 5 ) is opposite. To compensate for this error, a further considerable control effort is required.

Fig. 3 indicates the molecular interaction between fluid and the channel wall. As the corresponding diagram shows, a flow only takes place above a certain pressure (pi). This pressure (pi) is required to overcome the persistence between the fluid and the channel. Only a limited number of interfaces or image cells are possible for a given pump output. The pumps P1 and P2 are already active before the fluid in the channel ( 5 ) begins to move.

In continuation of the technical development, the device according to the invention. Fig. 4 to 8 emerged. Instead of a meander, individual parallel view channels ( 5 ), each with individually assigned micropumps P1 and P2 and mixers ( 2 ), are arranged so that the direction of flow of the fluid is the same in all view channels.

Fig. 4 shows the principle of a single channel. There is a mixer ( 2 ) at each input of a viewing channel ( 5 ) and the micropumps P1 and P2 at its inputs. The resistance in each channel ( 5 ) is significantly lower due to this arrangement and the parameters for the pumps P1 and P2, z. B. the pumping capacity of each individual pump can remain lower. At the same time, the initial pressure pi, which is to be applied for a flow in each of the channels ( 5 ) through the micropumps P1 and P2, also decreases.

Another and essential feature of the invention consists in the design of the mixer ( 2 ), in which the contrast-generating fluids 1 and 2 flowing from the two feed lines F1 and F2 are brought together, depending on the image content function at hand. For this purpose, the feed lines F1 and F2 - FIG. 4a - have a narrowing ( 15 ) of the cross section at their end, at which there is a safe STOP of the fluid 1 or 2 as soon as the corresponding pump P1 or P2 becomes inactive. At the cross-sectional constriction ( 15 ) of the feed line, a meniscus ( 14 ) is formed due to the tensioning force of the fluid, which prevents further outflow of the fluid and because of its surface tension, a boundary layer for the second fluid flowing through it, e.g. B. F2 forms. The cross-sectional constriction ( 15 ) of each feed line F1; F2 rounded. With this constructive design of the mixer ( 2 ), a safe control is carried out in the mixer ( 2 ) without additional sensors for synchronization being required on the mixer ( 2 ). This also reduces the effort for controlling the micropumps P1; P2.

The through the cross-sectional narrowing of the leads F1; The technical effect advantageously setting F2 in the mixer ( 2 ) is also used at the end of each viewing channel ( 5 ), in that there ( FIG. 4b) there is also a constriction ( 16 ) of the cross section, which in turn ensures a reliable STOP of the fluid. When the display is at rest, that is, both pumps P1; P2 are inactive, a stable state is established in the viewing channel ( 5 ).

The channel body ( 47 ) for the microstructure of the channels consists of a plastic, so that the advantageous channel geometries and cross-sectional constrictions ( 15 ; 16 ) are easy to implement.

The geometric arrangement of the structures of the view channels ( 5 ), the micropumps P1; P2, the mixer ( 2 ), the measuring channels ( 17 ) and sensors S11 to S22 on the channel body ( 47 ) are shown in more detail in FIG. 5. The mixers ( 2 ) are immediately upstream of the inputs of the individual parallel viewing channels ( 5 ). Since the micropumps P1; P2 does not belong to the channel body ( 47 ), only the pump inlet ( 31 ) and pump outlet ( 30 ) are shown. The pump inputs ( 31 ) for each fluid are connected in parallel to a manifold ( 18 ), which in turn is connected to the outputs ( 39 ) of a separator ( 10 ), not shown.

The outputs of the viewing channels also lead to the input ( 38 ) of the separator ( 10 ) via a collecting line. The circuit for the fluids is closed and the device is energetically stable. In each manifold ( 18 ) immediately in front of all micropumps P1; P2 are each a measuring section ( 17 ) with sensors S11; S12 and S21; S22 determined for a speed measurement of each fluid, with which a synchronization of the micropumps P1; P2 takes place. This means that only one measuring channel is required for each of the two fluidics for all channels.

In FIG. 6, the arrangement of FIG. 5, and shown in more detail in an electrical equivalent circuit of Figure 4. The flow resistances R, the flow Φ, the pressure pi and the required pumping power of the micropumps P1; Calculate or determine P2. When the pump P1 or P2 is active, sensors S11; S12 and S21; S22 the flow Φ ₁ or Φ ₂ determined. Against the defined forward resistance Dm1; Dm2, the required operating pressure pi is set when the system is set. When creating change information for the label, a micro pump P1 becomes active in accordance with its image cell to be realized and overcomes Dm1 in the mixer ( 2 ). The second inlet into the mixer ( 2 ) is blocked with Dm2. Via Rm1 and Rm2 there is a common set of sensors S11 / S12 and S21 / S22 for all view channels Rz1l to Rz1n, since the control device ensures that only one pair of pumps is working at a given time. Additional sensors in the mixer ( 2 ) for recognizing the interfaces can also be dispensed with.

Fig. 7 illustrates the construction of the electronic label. The channel body ( 47 ) is used together with a glass cover layer ( 46 ) in a housing ( 48 ), the top of the housing ( 48 ) at the same time a cover ( 50 ) for the image field, which is formed by the viewing channels ( 5 ), having. Below the viewing channels ( 5 ) there is a reflector ( 41 ) which clearly displays the display information even in weak ambient light. The separator ( 10 ) is also arranged below the channel body ( 47 ) and connected to it at four points. The pump chambers ( 35 ) are formed in bending plates ( 32 ) which, together with a piezo plate ( 34 ), form a bimorph. Contact rubbers ( 51 ) are each attached to the piezo plate ( 34 ). The feedthroughs ( 33 ) through the channel body ( 47 ) open into the pumping chambers ( 35 ). A separate printed circuit board ( 43 ) carries the necessary electronic assemblies ( 42 ). The space between the separator ( 10 ) and the printed circuit board ( 43 ) is provided for the arrangement of a solar cell ( 40 ) and a rechargeable battery ( 45 ) for buffering the energy supplied by the solar cell ( 40 ).

In FIG. 8, the arrangement of a micro-pump P1; P2 on the channel body ( 47 ) is illustrated by an enlarged view. The channel body ( 47 ) shows the molding of the view channels ( 5 ) and the inlet channels ( 49 ) for the pumps P1; P2, as well as their pump inlet ( 31 ) and pump outlet ( 30 ) as bushings through the channel body ( 47 ). The pumps consist of the bending plate ( 32 ), the pump chamber ( 35 ) and a piezo plate ( 34 ). When a voltage is applied to the piezo plate ( 34 ), the pump chamber ( 35 ) is compressed and the liquid contained is displaced.

With the constructive design of the device changes in the image content are in relatively short time possible because old information quickly from a parallel point of view channels can be pushed out. In addition, display errors are caused by Deviations in the contour of the characters when the ambient temperature changes or Temperature fluctuations without control effort even in the resting phase of the Etiquette compensated because the deviations in direction and size in every view channel are the same.  

Reference list

1

Fluid

1

2nd

mixer

3rd

Fluid

3rd

4th

Inlet meander

5

Viewing channel

6

Image cell

7

Overflow channel

8th

Image field coverage

9

Inlet separator

10th

separator

12th

Image cell transition

13

Image cell transition

14

Meniscus mixer

15

Narrowing inflow

16

Narrowing of the viewing channel

17th

Measuring channel

18th

Manifold

30th

Pump outlet

31

Pump inlet

32

Bending plate

33

Carrying out fluid

34

Piezo plate

35

Pumping chamber

36

Pressure sensor

38

Separator input

39

Separator outputs

40

Solar cell

41

reflector

43

PCB f. electronics

46

Glass cover

48

casing

50

Cover image field
a _s

Distance viewing channel
b _s

Wide viewing channel
δ _p

Pixel offset
lp image cell length
lü length overflow
P1 pump

1

f. Fluid

1

P2 pump

2nd

f. Fluid

3rd

S1 sensor

1

f. Measuring channel
S2 sensor

2nd

f. Measuring channel
S3 sensor

3rd

f. Fluid

1

S4 sensor

4th

f. Fluid

3rd

F1 fluid supply line

1

F2 fluid supply line

3rd

pi pump pressure
S11 sensor
S12 sensor
S21 sensor
S22 sensor

42

Electronic components

45

Battery (supercap)

47

Channel body

49

Inlet f. pump

51

Contact rubber

Claims (6)

1. Device for displaying prices, article names and similar information on goods carriers in department stores and warehouses with the aid of display devices attached to the goods carriers in electronic labels, each electronic label consisting of a graphic display device with a fluidic system which is an energetically bistable contrast-generating image cells, characterized ,

• - That the fluidic system of the display device consists of a plurality of parallel and along an information line arranged microchannels ( 5 ) which are independent of each other,
• - that each microchannel ( 5 ) has a visible area (ls) and on the input side a micromixer ( 2 ) with two feed lines (F1; F2) for different contrast-generating fluids ( 1 ; 3 ),
• - wherein each feed line (F1; F2) of each mixer ( 2 ) is preceded by a micropump (P1; P2),
• - That a common flow meter (17; S11, S12) is arranged for each fluid for all viewing channels ( 5 ),
• - And all the feed lines (F1; F2) for the mixer ( 2 ) and all the discharges ( 38 ) of the viewing channels ( 5 ) are connected to a common separator ( 10 ) as a store for the two fluids.

2. Device according to claim 1, characterized in that the two inputs (F1; F2) of the mixer ( 2 ) have a cross-sectional constriction ( 15 ). 3. Apparatus according to claim 2, characterized in that each viewing channel ( 5 ) has a cross-sectional constriction ( 16 ) at its end. 4. Apparatus according to claim 2 and 3, characterized in that the cross-sectional constrictions ( 15 ; 16 ) are rounded. 5. The device according to claim 1, characterized in that the common flow meter is a pressure difference meter over the measuring channel ( 17 ). 6. The device according to claim 1, characterized in that the common Flow meter is a thermal flow meter.