WO1997003429A1 - Display element - Google Patents

Abstract

A display element (1) has first and second constituent surfaces (3, 4) of differing colors and has movable elements (6, 7) that are disposed so that at least part of the first constituent surfaces (3) can be approximately covered by at least one part of the movable elements (6, 7) so that a figure or character is depicted. The movable elements (6, 7) have a color like that of the second constituent surfaces (4). The first constituent surfaces (3) are, for example, segments of a 7-segment display or pixels arranged in a matrix. The display element (1) is designed preferably as an electronic chip with micromechanical elements. A plurality of display elements (1) can be combined to form a display unit which, for example, can be used as a counter in odometers, supply meters, etc.

Description

Display element

The invention relates to a display element of the type mentioned in the preamble of claim 1.

Such display elements are suitable, for example, for displaying the mileage in vehicles, the fill level of a tank, a consumption value in meters of all kinds, etc.

An electrostatic miniature display arrangement is known from the Swiss patent specification CH 633 902. The display arrangement consists of metallic flaps which are arranged in recesses in a substrate and can be rotated about a predetermined axis by means of an electrostatic field. Several flaps are e.g. combined into a 7-segment display. To display a specific number, the corresponding flaps of the 7-segment display are deflected from the rest position. The numbers shown are visible under normal lighting conditions. In the event of a power failure, all flaps turn back to their rest position: the display is not lost.

The invention has for its object to provide a display element that combines the two functions of displaying and capturing a value and capturing the displayed value even in a de-energized state.

The invention consists in the features specified in claim 1. Advantageous configurations result from the dependent claims.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawing.

1 shows a display element designed as a 7-segment display,

2 an electronic circuit integrated in the display element, FIG. 3 a counter formed from a plurality of display elements,

4 shows a second embodiment of a 7-segment display element,

5 shows a third embodiment of a 7-segment display element,

6 shows a display element designed as a matrix with 5x7 pixels and

7 shows a rotor-stator arrangement.

1 shows a display element 1 for displaying the digits "0" to "9". The surface 2 of the display element 1 facing an observer has seven first partial surfaces 3 and a second partial surface 4. The first partial areas 3 represent the bars or segments of a 7-segment display, the second partial area 4 takes up the remaining space on the surface 2. The subareas 3 have a predetermined color which differs from the color of the subarea 4 serving as background with as much contrast as possible. Examples of advantageous color combinations are red / white or white / black. The surface 2 is further provided with six bearing elements 5 in the form of protruding pins for mounting one movable element 6 or 7 each, the elements 6, 7 being rotatable about the corresponding pin 5. The elements 6, 7 are designed as parallel to the surface 2, designed disk-shaped structures. 1, the shape of the elements 6, 7 is such that an element 6 arranged at the four outer corners of the display element 1, depending on its rotational position, has one, both or none of the two partial surfaces 3 converging in its corner can cover the top to the middle. The two elements 7 are designed such that they can cover none, only one, two or all three of the partial surfaces 3 that meet in the form of a “T” on their pin 5. The color of the elements 6 and 7 is, if possible, the same as the color of the background area 4. For the sake of clarity of the drawing, only two elements 6 and one element 7 are drawn. The elements 6, 7 can now be brought individually into such a rotational position that each individual partial surface 3 is either completely visible or covered except for a small area in the middle of the two elements 6 and 7 covering it and is therefore invisible. Thus, the digits "0" to "9" can be displayed with the display element 1 as a 7-segment display.

So that the digits can be set according to a predetermined value or incrementally on the basis of counting pulses, each element 6, 7 is rigidly coupled to a drive element 8 that is not visible in FIG. 1. The display element 1 also contains an electronic circuit block 9 for controlling the drive elements 8. A block diagram of the circuit block 9 is shown in FIG. 2. The

Circuit block 9 has an input 10 for counting pulses and a reset input 11, six outputs 12 for controlling the drive elements 8 and an overflow output 13. Counting pulses arriving at input 10 are fed to a circuit block 14 which is designed as a BCD component (binary coded display) and has seven outputs 15 for direct control of a conventional 7-segment display and an overflow output 13. The seven outputs 15, the logical state of which indicates whether a partial area 3 (FIG. 1) serving as a segment should be visible or not, are fed to an interface circuit 16 which determines the rotational position for the elements 6, 7 corresponding to the segments 3 to be covered and controls the drive elements 8. The specific configuration of the interface circuit 16 is essentially determined by the type of drive elements 8. The display element 1 can be reset to the number "0" via the reset input 11. Every tenth counting pulse arriving at input 10 triggers a pulse at overflow output 13. It is not necessary to perform the functions of the circuit block 14 and the interface circuit 16 separately. A single circuit block can also be provided, which directly carries out the necessary electronic processing from the arrival of a counting pulse until the corresponding number is displayed.

To display a number consisting of several digits, as shown in FIG. 3, a plurality of display elements 1 can be combined in a cascade connection to form a display arrangement serving as a counter, the overflow output 13 of a display element 1 with the input 10 of the display element displaying the next higher decimal place 1 is connected. If a decimal number with a decimal place is to be displayed, as is the case, for example, with consumption meters or with odometers for displaying tenths of the unit of measure, the display element 1 displaying this position preferably has a different color combination than the other display elements 1. It is also possible to provide a number k of segments that is different from the number seven. It is also possible to combine a plurality of display elements 1 to represent multi-digit numbers, the number displayed also being able to belong to a number system other than the decimal system. The number of counting pulses that trigger a pulse at the overflow output 13 must be adjusted accordingly.

So that the information about the number shown is not lost in the event of a power failure of the circuit block 9 (FIG. 2), the circuit block 9 is either equipped with a captive memory 18 or intelligent sensors are arranged on the display element 1, by means of which the exact rotational position is arranged the elements 6, 7 can be detected. Instead of the memory 18, a circuit part is then provided which converts the signals supplied by the sensors into the value of the number shown. These sensors can also be used to precisely regulate the rotational position of the elements 6, 7 when a new number is set. The sensors can e.g. capacitive or optical type.

The display element 1 has lateral dimensions that are comparable to the dimensions of a conventional display element of a counter for consumption meters of all kinds, such as Electricity meters are in the range of about 2 * 3 to 5 * 8 mm ^. The linear dimensions of the elements 6, 7 are thus less than ten, typically one to four millimeters. There are various, predominantly micromechanical technologies which are suitable for the production of the elements 6, 7 and the associated drive elements 8. The circuit block 9, optionally the memory 18 and / or the sensors are advantageously directly in the surface 2 of the display element 1, e.g. in CMOS technology, integrated, the display element 1 consists of silicon.

For example, electrostatic or electromagnetic micromotors can be used as drive elements 8, in which a rotor is rotated electrostatically by means of a stator. Such motors can be manufactured in various technologies such as the technology of "Silicon Surface Micromachining" or "LIGA" (German acronym for lithography, electroforming, molding) technology. An overview of various technologies can be found in the article "A survey ofthe present State of microsystem technology" by S. Fatikow, U. Rembold and G. Wöhlke in the Journal of Design and Manufacturing (1994), volume 4, page 293 - 306. An electrostatic micromotor with a particularly high torque is known, for example, from the article "Integrated Electrostatic Stepper Motors, Microfabricated Sensors and Actuators, 1991, IMT, University of Neuchatel, pp. 11-13. From the aforementioned article by S. Fatikow et al., an electrostatically driven micro-vibromotor is also known. In this micro-vibromotor, a linear reciprocating motion is transferred into the rotary motion of a rotor. The micro-vibromotor offers the advantage that it manages with lower voltages than an electrostatic micromotor Instead of an electric one, a pneumatic drive type is also possible, in which an air flow generated by means of a micropump, the E elements 6, 7 rotates into the desired position. A suitable electrostatic powered pump with a micro membrane is also in the article by S. Fatikow et al. described. With other micropumps, their pumping movement takes place using the memory metal effect or a thermally controlled bimetal actuator. Also known are micromechanical transmissions that can be connected as a mechanical transmission stage between the drive element 8 and the elements 6, 7.

In a special embodiment of the display element 1 described, the elements 6, 7, as shown in FIG. 4, are designed as disks, the edge of which is provided with teeth 20. The teeth 20 of adjacent elements 6, 7 engage in one another, so that the rotary movements of all elements 6, 7 are rigidly coupled. Only a single drive element 8 is required to represent the digits "0" to "9". The drive element 8 rotates each element 6, 7 step by step by a predetermined angle Δφ = 3607p, where p is an integer. After p steps, each element 6, 7 has rotated through 360 °. If p = 10, the digits "0", "1", ..., "9" can be displayed one after the other. The elements 6, 7 are now formed with slots 21 such that in each discrete rotational position ψQ = 0 °, ψ \ = Δφ, cf> 2 = 2 * Δφ, ..., φ 9 = 9 * Δφ which is the corresponding digit performing segments 3 are exposed and the other segments 3 are covered. The display element 1 shown in FIG. 4 displays the number "2". With one disk 6, more than one slot 21 is drawn, with the other disks 6, 7 only one slot 21 is drawn. Since there is the possibility that a certain surface of the elements 6, 7 would have to be part of a slot 21 at a rotational position φ _a , but not in another rotational position φb, better results can be achieved with p = l 1 or p = 13. In these cases, the electronic circuit 9 is expanded by a logic circuit so that the drive element 8 rotates the elements 6, 7 by the angle (p-9) * Δφ when changing from the number "9" to the number "0". In another solution, it is possible that the rotation by the angle (p-9) * Δφ does not occur all at once when changing from the number "9" to the number "0", but is distributed over different number changes, so that an optimal arrangement the contactor 21 can be reached. The electronic circuit 9 is to be adapted accordingly. Another possibility is to choose a subdivision into p = 10 steps so that after ten steps the elements 6, 7 are rotated through 360 °, but the elements 6, 7 are not at the same angle with each step Δφ are rotated, but by a predetermined angle θ _n with n = 0, 1, ..., 9. The sum of the angles ΘQ + θ \ + Θ2 + ... + θ _n is 360 °. The electronic circuit 9 is therefore expanded by memory elements that cannot be used for storing the currently displayed number and for storing the angles ΘQ, ..., θ _n , and is set up, in each case the elements 6, 7 upon arrival of a next count pulse by the change of the corresponding one Digits correct angle θ. Alternatively, the display element 1 is equipped with intelligent sensors for detecting the displayed digit and with memory elements that cannot be stored for storing the angles ΘQ, ..., θ _n , so that the elements 6, 7 also rotate by the correct angle θ when a next count pulse arrives .

In an advantageous embodiment, a lens for the optical enlargement of the numbers shown is arranged above each display element 1 (FIG. 1), which, with a constant visual impression, is a allows further miniaturization of the display elements 1 and a reduction in their unit costs.

5 shows a further exemplary embodiment of a display element 1 with k = 7 segments 3a, 3b. To cover the segments 3a, 3b, eight flaps are provided as movable elements 6, 7. One flap 6 is assigned to each of the segments 3a, and two flaps 7 are assigned to the segment 3b. The bearing elements 5 for the rotatable fastening of the flaps 6, 7 are arranged such that the flaps 6, 7 are rotatable about an axis arranged perpendicular to the surface 2 of the display element 1. The flaps 6 are dimensioned such that they can completely cover a segment 3a, the flaps 7 so that they can cover approximately half the length of the segment 3b. The flaps 6, 7 are formed in the vicinity of the bearing elements 5, for example as a gear 22, in which a gear 23 of the associated drive element 8 engages. The drive element 8 is, for example, a micromotor manufactured in "LIGA" technology, the rotor of which is rigidly coupled to the gear 23. The use of a transmission consisting of at least these two gear wheels 22, 23 allows a simple translation between the drive element 8 and the corresponding flap 6, 7, so that on the one hand the micromotor has to apply a lower torque and on the other hand a more precise adjustment of the rotational position the flaps 6, 7 is possible. In the representation of the various numbers or characters, each flap 6, 7 either covers the associated segment 3a, 3b or exposes it. In order to ensure that the flaps 6, 7 perfectly cover or release the segments 3a, 3b, two cams 24, 25 serving as stops are provided, which limit the freedom of movement of the flaps 6, 7. When a new number is set, the drive element 8 is activated for a predetermined period of time, which ensures that the assigned flap 6 or 7 is moved as far as the stop on the corresponding cam 24 or 25.

Instead of the rotatable flaps 6, 7, flaps displaceable along an axis can also be used. A combination of a rotary and a translational movement is also conceivable. Examples of such elements and a technology for making such elements are disclosed in Muller et al., U.S. Patent No. 4,740,410. described, which is hereby inserted as a reference.

FIG. 6 shows a display element 27 designed as a matrix with 5x7 pixels 26. For the sake of clarity, the same elements are not drawn 35 times, but only as often as is necessary for understanding. The pixels 26 represent first partial areas of a predetermined color and are arranged in five columns and seven rows. The background area has, as the second partial area 4, a color that clearly contrasts with the pixels 26. A movable element 28 is assigned to each pixel 26, so that each pixel 26 can be covered individually. The elements 28 are of the same color as the background area 4. The display element 27 is provided with an integrated electronic circuit 31 for controlling the elements 28. The circuit 31 has a counting pulse and a reset input, as well as an overflow output. A digit is displayed analogously to a display element formed with light-emitting diodes, in that the "luminous" pixels 26 are visible and the "non-luminous" pixels 26 are covered by the associated element 28. The elements 28 are held on the bearing elements 5 so as to be rotatable about an axis perpendicular to the surface 2 of the display element 27. The rotational movement of each element 28 is through two cams 24, 25 serving as stops are limited so that the associated pixel 26 is visible when the element 28 stops on the cam 24 and is not visible when it stops on the cam 25.

In the case of the cams 24, 25, photodiodes 29, 30 with an evaluation circuit are also integrated in the surface 2 of the display element 27 and connected to the circuit 31. The photodiodes 29, 30 and the evaluation circuit represent an intelligent sensor with which the position of the element 28 in natural ambient light can be detected electronically at any time, in particular after a power supply failure. The circuit 31 is therefore set up to query the position of all 5 × 7 elements 28 each time it is supplied with voltage again after an interruption. As soon as the circuit 31 receives a counting pulse, the circuit 31 ensures that the elements 28 are rotated up to the stop on the cam 24 if the corresponding pixel 26 has to be visible, or up to the stop on the cam 25 if the corresponding pixel 26 does not must be visible.

The element 28 can be manufactured in an expanded "LIGA" technology and, as shown in FIG. 7, preferably contains a rotor 32 made of electrically conductive material, which acts as a drive element in the side of the element 28 facing the surface 2 ( Fig. 6) is integrated. The surface 2 of the display element 27 is formed with integrated stators 33 for driving and a bolt for mounting the element 28. The number of rotor blades is e.g. four, the number of stators 33 eight. The electronic circuit 31 is constructed similarly to the circuit block 9 shown in FIG. 2 and will not be described in more detail here.

The display element 27 can be produced as any display element with m x n columns and rows. Other sensors, in particular of a capacitive type, can also be used to control the photodiodes 29, 30. It is also possible to provide the display element 27 with further electrical outputs, so that the number displayed and detected by the sensors after a power failure can be transmitted to the outside. Furthermore, a captive memory element can take over the function of the sensors.

The formation of the display element 27 with the counting pulse input 10 and the reset input 11 permits serial control for displaying a new number or a new character, by first setting the reset input 11 and then assigning the counting pulse input 10 one of the numbers or characters Number of counts is transmitted. However, other solutions are also conceivable in which there is a large number of inputs, so that a new number or a new character can be set at least partially as a unit.

The described micromechanical display elements 1, 27, which are designed as an electronic chip with micromechanical elements, have several advantages. This means that they can be read by the eye even when there is no power supply. If they are equipped with intelligent sensors, they also represent an unusable memory and are therefore particularly suitable for counters. The space required in depth is much less than with a conventional counter. Finally, they can be mounted directly on a circuit board like a semiconductor component. Smaller ones Inaccuracies in the design of the micromechanical elements hardly affect the visual impression that the display element conveys to a human viewer.

Instead of contrasting colors, the partial areas 3, 4 can also produce other optical effects, which e.g. based on diffraction and / or interference.

Claims

PATENT CLAIMS 1. Display element (1; 27) with movable elements (6, 7; 28) for the display of numbers and / or characters, characterized in that the surface (2) of the display element (1; 27) into first and second partial areas (3 , 4; 26, 4) different color is divided that the surface (2) bearing elements (5; 34) for receiving the movable elements (6, 7; 28) that the movable elements (6, 7; 28) of are similar in color to the second part surfaces (4) and that they are arranged in such a way that at least one part of the first part surfaces (3; 26) can be covered by at least part of the movable elements (6, 7; 28) so that one Number or a character is shown. 2. Display element (1) according to claim 1, characterized in that it is designed as a chip with micromechanical elements. 3. Display element (1) according to claim 1 or 2, characterized in that the first partial areas (3) are k segments of a segment display and that movable elements (6, 7) are present for almost completely covering or not covering the first partial areas (3) are. 4. Display element (1) according to claim 3, characterized in that the number k of the segments is seven. 5. Display element (27) according to claim 1 or 2, characterized in that the first partial areas (26) are arranged as pixels (26) of an nxm matrix in n columns and m rows and that each pixel (26) has a movable element (28 ) is assigned to cover or not cover. 6. Display element (1; 27) according to one of claims 1 to 5, characterized in that the display element (1; 27) has a counting pulse input (10) and a carry output (13). 7. Display element (1; 27) according to one of claims 1 to 6, characterized in that above the display element (1; 27) a lens is attached for the optical enlargement of the represented number or the displayed character. 8. Display element (1; 27) according to any one of claims 1 to 7, characterized in that intelligent sensors (29, 30) are provided so that the position of the movable elements (6, 7; 28) and thus the number or the displayed character can be recorded electronically even after the power supply has been cut off. 9. Display element (1; 27) according to one of claims 1 to 8, characterized in that an electronic circuit block (9; 31) is integrated in the display element (1; 27) to control the movable elements (6, 7; 28). 10. Display arrangement from a plurality of display elements (1; 27) according to one of claims 1 to 9 Representation of numbers, characterized in that in each case the carry output (13) of a display element (1; 27) is connected to the counting pulse input (10) of the display element (1; 27) representing the next higher number.