Keypads and key switches

Keypad and key switch

Technical field

The present invention relates to a small keyboard, and also relates to a key switch for the small keyboard and the keyboard.

Background technique

Miniaturization of electronic products is a basic principle of technological progress. The competitive advantage and success of the production line depends on whether a company can provide products with increased functionality and increased portability. With the development of science and technology, it is increasingly possible to miniaturize electronic circuits below the human scale. As a result, the interface (such as display screen, keypad, cursor control device) alone determines the size of portable products. Therefore, the ergonomic quality and size of input devices (such as small keyboards) play an increasingly important role in the recognition and success of products.

One type of keypad or keyboard that provides a particularly space-saving input device is the Independent and Combination Key (IACK) keypad, which has multiple rows of effectively lower concave combinations interspersed in a row of effectively raised convex independent key areas Key area. The IACK keypad has independent and combined key areas, usually arranged in alternating rows and columns. The independent key area of my previous IACK keypad is such a small keyboard element, when it is pressed independently of the adjacent key, an output related to it is generated. On the contrary, the key combination area of my previous IACK keypad is such small keyboard elements that have adjacent independent keys (for example, the corners of the combination key area oriented diagonally), and do not correspond to them under the key pad Key switch. The output corresponding to the combined key area is generated by pressing two or more adjacent raised key areas combined together.

Even if there is no need to trigger switch combinations corresponding to other key areas to generate output for some key areas in the keypad, other improvements that lead to reliable operation of smaller and smaller keypads are also needed. For example, it is seeking to improve the structure of the key switch so that a single clear tactile feedback event can be used to reliably and almost simultaneously close multiple electrical connections. There is a type of keyboard or small keyboard, including the IACK keypad, which needs to realize multiple key switch contacts at the same time. The button dome (made of metal, plastic, etc.) that operates in the buckle mode provides high-quality tactile feedback. However, it is difficult to make reliable and instantaneous connection of more than one key switch contacts at a time.

Summary of the invention

According to one aspect of the present invention, an improvement is provided to a keypad having an array of key areas. The key area array includes a column of raised key areas and key areas interspersed between the raised key areas, and each raised key is The areas provide a corresponding character output, and the key areas interspersed between the raised key areas provide character output at least partly according to an operation algorithm, and the operation algorithm includes triggering at least one adjacent raised key area. The improved feature is that the corresponding and independently triggerable key switches are placed under the scattered key areas, and the operation algorithm also includes triggering the relevant switches under the scattered key areas.

Preferably, the center-to-center distance of adjacent raised key regions is less than about half the width of an adult's finger.

In some cases, the corresponding tactile feedback element is located under each raised key area and each scattered key area.

In some embodiments, the operating algorithm generates an output corresponding to the scattered key area in response to detecting the combined switch trigger, and the combined switch trigger includes any switch under the raised key area and a switch under the scattered key area. switch.

In some cases, the operation algorithm generates an output corresponding to the scattered key area in response to detecting the combined switch trigger, and the combined switch trigger includes a switch under the scattered key area and any one directly connected to the scattered key area. The switch below the adjacent raised key area.

In some cases, each switch placed under the scatter key area is directly connected to a switch placed under another scatter key area on its side, and connected to a switch placed under a raised key area on the other side. Switch on.

In at least some embodiments, the interspersed key area has a convex exposed surface. In other cases, they are basically flat.

In some cases, each raised key area includes a raised ridge that defines a top surface, and each scattered key area is directly adjacent to a plurality of raised key areas.

In some embodiments, the keypad includes a printed circuit board with traces that electrically connect each of at least some of the switches under the raised key areas to one switch under the corresponding scattered key area.

In some cases, the keypad has a printed circuit board with four electrical trace extensions that extend below each interspersed key area to form switch contacts. For example, the two trace extensions below each scatter key area can be connected to a tactile dome, while the other two trace extensions are connected to the exposed traces. When the scatter key area is triggered, The exposed trace momentarily enters an electrical contact state.

In some preferred structures, electrical traces in the intermittent contact between the printed circuit board and the inner surface of the metal button dome are used to trigger each switch placed under the interspersed key area. Preferably, the traces that are in intermittent contact with the surface of the button dome form three separate contacts, which are separated from each other on the circular contact area under the button dome. For example, the trace can be a pie under the button dome.

In some cases, each switch placed under the interspersed key area includes a tactile feedback element and a carbon electrode ring. In these cases, the tactile feedback element may be electrically passive. Each switch placed under the scatter key area can connect three signal traces to form a single channel from one side of the array to the switch, and two channel points from the other side of the array.

In some small keyboards, the raised or scattered key areas are respectively the areas of the molded plastic key pad, and the key pad flexes during the key activation process. In some cases, those key areas that are not areas of the molded plastic key pad are exposed through separate holes in the key pad. In some cases, the button dome actuators are molded so that they protrude from the lower surface of the key pad. The key pad can also be molded integrally with the product shell.

In other cases, the key area is the upper surface of the key fixed to the sheet, and the sheet remains stretched on a row of key switches. The stretched sheet may include, for example, an elastic resin sheet. Preferably, the elastic sheet maintains a stretched state of at least 20% in at least one direction. In some cases, the stretch sheet includes a plastic sheet, and the plastic sheet is molded to have elastically stretchable areas, such as wrinkles protruding from the main surface of the sheet.

According to another aspect of the present invention, an improvement is provided to a keypad. The keypad includes a key pad and a switch bottom layer located under the key pad. The key pad has an exposed upper surface that forms a separate raised surface. The key area, when the raised key area is pressed independently of the adjacent key area, an output related to it is generated. The key pad also defines other key areas scattered between the adjacent raised key areas and marks them with Indicates other related output. The improved feature is that the key pad is rigidly maintained in a stretched state across the switch bottom layer at its periphery.

In some embodiments, the raised key area is the upper surface of the rigid key fixed on the elastic sheet.

Preferably, the elastic sheet maintains a stretched state of at least 20% in a given direction, or keeps stretched in both orthogonal directions.

Some examples are characterized in that the key pad has a plastic sheet, and the plastic sheet is molded to have elastically stretchable areas, such as wrinkles protruding from the main surface of the sheet.

In some embodiments, the keymat defines a peripheral hole, which receives the pins of the rigid keypad housing when the keymat is extended.

According to the third aspect of the present invention, the key switch includes a printed circuit board having at least two switch contacts, the at least two switch contacts are usually electrically insulated from each other, and a metal button placed on the printed circuit board Dome. The dome has a raised middle area that forms a downwardly facing chamber. The chamber is defined on its edge by a ridge placed above the switch contact, so that when the button dome is triggered, the ridge around the central area is over the switch contact. The ring-shaped contact area of the dot mates with the printed circuit board to make electrical contact between the button dome and the switch contact.

In some embodiments, the button dome has an outer edge that is placed against and in electrical contact with the reference trace on the printed circuit board.

Preferably, the annular contact area is approximately one third of the nominal diameter of the metal dome.

In one illustrated embodiment, the switch contacts are wedge-shaped. Preferably, each switch contact extends over approximately 20 degrees in the circumferential direction of the contact area.

Preferably, the switch contacts are placed approximately equally spaced from each other around the contact area.

In some cases, the ridges form a continuous loop. In other cases, the ridge includes a circle of separated ridges or ridge segments.

In some applications, the button dome is placed on three separate switch contacts.

In some cases, the switch contacts are thick enough so that the flexed button dome touches all underlying switch contacts before touching any other surface of the PCB. Preferably, the button domes are thin enough and the switch contacts are separated by sufficient spacing so that the When the flexed dome contacts all the switch contacts below, the dome can further flex toward the PCB between adjacent switch contacts.

In another improvement of the present invention, the keypad includes a key pad and a switch bottom layer located below the key pad. The key pad has an exposed upper surface that forms a separate raised key area. When the adjacent key area presses the raised key area, it produces related output. The key pad also defines other key areas scattered between the adjacent raised key areas. The bottom layer of the switch includes the related and raised key areas. Switches and switches directly below the corresponding scatter area.

According to another improvement of the present invention, the keypad has an array of key areas, including a column of raised key areas and key areas interspersed between the raised key areas, and each raised key area provides a corresponding key area when triggered. The key areas interspersed between the raised key areas provide character output at least in part according to the operation algorithm. The operation algorithm includes triggering at least one adjacent raised key area, and the scattered key area has an obvious raised upper surface .

Placing multiple switches under one finger conflicts with the basic principle of reasonable ergonomic design: that is, to provide a clear tactile feedback for each received input. The high level (metal dome) tactile feedback provided in some of my early attempts produced unsatisfactory reliability of the combination keys, and each input had multiple "ticks". The final solution given by some of the embodiments disclosed here requires multiple simultaneous changes, including changes that will have some adverse effects. These changes include the addition of additional tactile feedback (as a way to solve the problem that there is already too much feedback) , Add a sub-array to the PCB array (without some of the improvements disclosed here), these changes will increase the number of lines of the central processing unit, and in some respects also include the use of non-raised and raised keys The inter-grading method abandons the early concept of IACK (that is, the raised key with a relatively diagonal angle produces an output related to the central composite key area), in which the non-raised key is dominant. In addition, the improved key pad structure improves the ability of ordinary fingers to reliably trigger independent and combined keys.

Provide a small keyboard structure, which uses the relative height and relative strength of a single dome structure, where the height and strength are relative to the four surrounding it, and the relatively weaker key pad itself is also used. Deflection force. This structure is particularly advantageous for use with convex, non-rising keys.

By narrowing the traces in contact with the discontinuities and thickening the metal of the traces, the reliability of multiple switches in contact with a single metal dome is increased, so that when the discontinuities are in contact with three separate contacts, they are located in three The part of the discontinuity between the separated contacts can be deflected towards the printed circuit board in terms of material. In particular, the reliability of achieving multiple contacts at a time can be enhanced, especially if the button dome and the trace are in contact with each other only at "three points" or at positions that divide the diameter into approximately three sections.

Under extreme temperature changes, the difference in material properties in the elastic keypad mesh structure held in the plastic casing may cause the failure of contact with the button dome. In order to maintain contact between the key pad actuator and the dome without using an adhesive (which increases service and manufacturing troubles), it is desirable to assemble the key pad in a pre-pressed or stretched state.

Some aspects of the present invention make it possible for a small keyboard, while at the same time, no matter whether it is a raised or a non-raised key, it still has clear and subjectively good tactile feedback for each key input. Other features disclosed and required herein can improve the durability of the keypad, such as providing a hard plastic keypad so that the keypad and the shell can be integrally formed, and the number of edges exposed on the tiled surface of the keypad is minimized. Additional improvements increase the service life and operability of the flexible key pad. The improved dome switch structure disclosed herein can utilize a single tactile feedback to the user to produce a reliable and almost simultaneous connection across two or more contact paths.

One or more embodiments of the present invention are described in detail in the drawings and the following description. Some of these embodiments are described with reference to the improvement of the IACK keypad, or with reference to those keypads with key areas. The output of the key area is only determined by the combination of switches related to the adjacent, raised key area. However, it should be understood that several aspects of the present invention are not limited to these types of keypads, and other aspects also have different operating algorithms. Other features, objects and advantages of the present invention will become apparent through the following description, drawings and appended claims.

Description of the drawings

Figure 1 shows the first printed circuit board (PCB) of the keypad, with some of the switches including exposed carbon electrodes and metal dome switch plates.

Figure 2 shows a cross-section of a keypad with raised and scattered key areas.

Figures 3 and 4 show the combined key area and the independent key area that trigger the thermoformed IACK key pad, respectively.

Figure 5 shows a narrow actuator column molded in a backfill elastomer.

Figures 6 and 7 show the operation algorithm for the keypad.

Figures 8 and 9 show circuit board layout diagrams used with Figures 6 and 7.

Fig. 10 shows a finger pressed on the raised key area.

Figure 11 shows a finger pressed on the raised non-rising key area.

Figure 12 shows a finger pressed on a flat non-rising key area.

Fig. 13 shows a finger pressed on a raised key area having a raised edge.

Figure 14 shows the elastic key pad removed from the housing.

Figure 15 shows the keypad of Figure 14 assembled.

Figure 16 shows a keypad with key pads molded with fold points.

Figure 17 shows a key pad with independent key areas defined on a rigid structure.

Fig. 18 is a cross-sectional view taken along line 18-18 in Fig. 17;

Figure 19 shows a key pad with a combined key area, which is defined on a rigid structure.

Fig. 20 is a cross-sectional view taken along the line 20-20 in Fig. 19.

Figure 21 is a cross-sectional view through the metal dome, which is designed to contact multiple switching elements at a time.

Figure 22 shows the PCB traces under the dome of Figure 21.

Figure 23 shows the discontinuous ring element on the underside of the metal dome.

Similar reference numerals are used in the various drawings to refer to similar elements.

detailed description

Figure 1 shows a switch 21, which houses a traditional button dome 12 made of metal or plastic (Figure 3) under the independent key 11 of the IACK keypad, so that it is located on the drive line 24 (shown vertically) and read An instantaneous connection is provided between the two lines at an intersection of the outlet line 26 (shown horizontally). The IACK keypad has a column of independent key areas 11 distributed between the combination key areas 22 (also refer to Figures 3 and 10). ). The base of the button dome 12 (preferably formed of metal) rests on the printed conductive substrate 29, and the printed conductive substrate 29 is in electrical contact with the driving line 24 on it, and the center of the switch 21 is electrically connected to the readout line 26 on its right side. Connected. In this way, triggering the related button dome 12 is electrically equivalent to triggering the switch on the upper right side of the expected combination key 22 and below the independent key 11. An auxiliary contact 20 is also shown, which is in electrical communication with the drive line 24 below it, and the auxiliary contact 20 is in electrical communication with the sense line 26 on its left side. The tape layer covers the button dome 12 to avoid contact with the auxiliary conductor 18 (FIG. 3 ), and also has a cutout corresponding to the auxiliary contact 20 to allow the auxiliary conductor to contact the PCB. In this way, triggering the related button dome 12 is electrically equivalent to triggering the switch located on the lower left side of the expected combination key 22 and below the independent key 11. Triggering these two independent keys 11 at the same time (opposite to each other on the diagonal across a combination key 22) gives the controller an instruction that it wants to trigger the central combination key.

2 shows the drive line 24 electrically insulated from the sense line 26, but at each independent intersection 14 corresponding to the position of the independent key region 11, the sense line 26 and the drive line 24 may be electrically connected. Similar to the previous IACK keypad, the software of the system records the input of the combination key as a result of triggering at least two diagonally adjacent (ie relatively adjacent) independent key regions 11. For example, the system records the triggers "E" and "L", or "F" and "K" as the intent to enter the number "3". However, in this array, the trace extension portion 50 extends from each of the four trace segments defining each combination key area 22 to each combination intersection point 15 where they are almost in contact with each other. The trace extension portion 50 extends into the contact area 141 in each combination key area 22. The trace extension 50 can be made of conductive ink, and the conductive ink can be selectively doped or changed in other ways, so that a unique resistance can be provided at each intersection during contact, so that the trace resistance can be detected by Be able to identify the intersection of contact.

Trigger the combination key 22 directly above the combination cross point 15 to close the contact between the adjacent ends of the four trace extension portions 50 at the combination cross point 15, thus connecting the adjacent pair of drive lines 24 and one. For the sense line 26, this is electrically equivalent to triggering all four surrounding independent intersections 14. Examples of switch structures connecting all four trace extensions 50 of a given combined intersection 15 are given in FIGS. 1 and 21-23.

FIGS. 3-4 show the operation of the IACK key pad 30a having a sheet 70 formed in an undulating surface shape, exposing the key area, and the key pad 30a includes elements for independent keys 11 and combination keys 22. The sheet 70 may be formed of a relatively hard material, such as polycarbonate or polyester, and formed by a process such as heating. For example, the thickness of the sheet is preferably 0.002 to 0.005 inches. Under each independent key area 11, there is an actuator 36 formed of other materials, which is formed in an appropriate position by injection molding or the like. The actuator 36 is placed directly above each high feedback position n (such as a metal or polyester dome). Similarly, under each key combination area 22, there is an actuator 36 and a high feedback button dome 12.

As shown in the figure, there is a difference in the gap between the lower surface of the actuator 36 and the button dome 12 associated therewith. The contact area between the sheet 70 and the actuator 36 of the independent key 11 is limited to the part where the independent key 11 does not deform during use, and is mainly the top flat area contacted by the finger 55 during the process of triggering the independent key 11. The purpose is to transmit force to the tactile feedback element 12 while minimizing the rigidity of the inclined side of the independent key 11. The structure or structures that transfer force between the sheet 70 and the tactile feedback element (button dome) 12 need not be connected to the sheet 70. The actuators 36 located under the independent key area 11 at rest are separated from their associated haptic elements by a distance "d", which is at least slightly greater than the stroke length of the haptic elements. In the illustrated embodiment, the height and stroke length of all button domes 12 are the same. Tactile feedback (especially giving a very clear and sensible feedback to a detected input) is a very important aspect of any keypad, and is in contrast to technologies that place multiple tactile elements directly under the users fingers (such as IACK). ) Essentially different. When the combination key 22 or the independent key 11 is pressed, this structure provides a separate, clear tactile feedback in the IACK keypad.

As shown in the figure, the independent key actuator 36 is only located below the highest plateau area of the independent key area 11, and the main part of the finger triggering force is applied to this area. In this way, in the process of triggering the key, the inclined sides of the raised independent key area 11 will not bend because they are not restricted by the actuator 36.

When the user's finger 55 presses and enters the characters printed on the combination key 22 (FIG. 3), some deformation occurs in the sheet 70', but the main result is that when the expected combination key area 22 flexes downward, The adjacent independent key area 11 also flexes downward. However, it is obvious that, as shown in FIG. 3, the button dome 12 directly below the combined key area 22 is unbuttoned at a lower deflection distance compared to the button dome 12 of the adjacent independent key area 11. This responds to the trigger combination key 22, providing a separate and obvious tactile feedback (such as from a metal or polyester fiber dome).

Conversely, when the user's finger 55 presses and triggers the independent key area 11 (FIG. 4 ), the button dome 12 directly below the independent key is first released before any of the surrounding tactile elements are unbuttoned. As long as the force required to deflect the sheet 70 around the independent key area 11 triggered by the deflection is less than the combined release force of the button dome 12 located below the adjacent key combination area 22, the selected independent key 11 will continue. Priority is always given to unlocking only the button dome 12 associated with it.

Figure 5 shows a key pad 30b, which is a variant of the embodiment of Figure 3, in which the actuator 36 is formed of a hard, light-permeable material, and/or has a conical shape to minimize material compression while Has improved light transmission performance. This can be formed by a two-step modeling, in which a mesh structure 97 made of an elastic material is formed first, and the actuator 36 is formed of a material with a higher hardness in the second step. Another alternative method is to use insert molding to manufacture the concentrator 36 in a softer elastic material. The upper surface of the concentrator 36 may be formed with letters or other symbols capable of distinguishing the key area.

FIG. 6 shows a decoding method that simplifies the software, which reduces the processing steps required to operate the IACK keypad and can ensure high-quality tactile feedback in the IACK keypad. In step 100, two types of keys are created in the software. They can simply be a list of two types of keys (11 and 22), or a list of one type of keys and consider the remaining keys as (by default) the second type of keys. The independent key 11 is designated as the auxiliary category, and the combination key 22 is designated as the dominant category. It is worth noting that the relative position of the specific independent key 11 and the combination key 22 is not part of the decoding algorithm, but the absolute position and class are used to define the expected output. In contrast, in some early IACK keypads, knowing the relative position of each key is essential for operation. In step 102, the system detects that the user has pressed an auxiliary key, such as the independent key 11. The system can display this key or wait for a given delay period. In step 104, before releasing the auxiliary key, the user presses (and the system detects) another key to trigger. The software does not need to analyze which diagonal is involved and perform the correlation between the selected diagonal and the combination key between the diagonal, because any key of the dominant type can replace the key of any auxiliary type. Referring briefly to Figure 9, in some previous IACK keypads, triggering the'A' key requires triggering the raised key areas 1 and 6, or 2 and 5. However, in this algorithm, the combination of any number key from 1 to 12 and'A' will produce the output of'A' just like the key'A' itself. The position of the independent key does not matter. In step 106, the system discards the auxiliary key and selects the dominant key. This algorithm may not be used in some prior art IACK keypad structures, which have high-quality tactile feedback and operate according to the following principle, that is, the relatively adjacent independent keys 11 indicate that they want to trigger the key combination. twenty two. In these cases, in order to reduce the overall size, the distance between the independent keys to be separated from each other is less than half the width of an adult finger, then at least two button domes 12 (in the small keyboard with button domes) need to be triggered to operate the combined key . This algorithm (or the algorithm of FIG. 7) combined with the raised key combination structure of FIG. 11 can allow high-quality tactile feedback for individuals in the IACK keypad.

Figure 7 shows another decoding method that simplifies the software, which reduces the processing steps required to operate the IACK keypad and can ensure high-quality tactile feedback in the IACK keypad. This method (similar to the method of FIG. 6) is suitable for use with the printed circuit board layout diagrams shown in FIGS. 8 and 9. In step 110, similar to step 100 in FIG. 29, two types of keys are distinguished. However, in step 112, another list is created in which each dominant key is associated with an adjacent auxiliary key. Referring to Figure 9,'A' is associated with 1, 2, 5 and 6;'B' is associated with 2, 3, 6 and 7;'C' is associated with 3, 4, 7 and 8; D'is associated with 5, 6, 9 and 10;'E' is associated with 6, 7, 1 0 and 11 are linked together;'F' is linked with 7, 8, 11 and 12. Note that the same result can be achieved by creating a single set of lists so that one of the predetermined elements belongs to a special class, such as'A,1,2,5,6';'B,2,3,6,7'; 'C, 3, 4, 7, 8';'D, 5, 6, 9, 10';'E, 6, 7, 10, 11';'F, 7, 8, 11, 12', where each A special character in this list (the first character in this example) is the dominant key. Other characters that mark physically adjacent keys can be arranged randomly, because the position relative to the dominant key (combination key 22) is not important. In step 115, the user presses multiple keys and the system detects these keys. In step 117, the system refers to the classification and priority order made in steps 110 and 112. If one or more auxiliary keys are detected in the initial input stroke, and the system subsequently detects a dominant key (before all auxiliary keys are invalid), in step 106, the system discards the auxiliary keys and selects the dominant key. Similar to the method in Figure 6, unlike many existing IACK keypads, the output is not entirely based on the combination of relatively adjacent keys. This method combined with the PCB layout of Figure 8 can also successfully distinguish independent, combined, and fuzzy key groups in a single cycle by driving adjacent drive lines at the same time. Specifically, in some prior art IACK keypads, it is possible to simultaneously drive adjacent lines and thereby determine a combination key in a single step, if two adjacent horizontal keys or two adjacent vertical keys are pressed , This way will produce vague results. This ambiguity requires a second cycle to determine the true state of the switch array. This problem is solved now, because the adjacent drive lines can be pulsed at the same time to provide unambiguous array information and accurately determine the group sum of independent keys and effective key combinations in a single cycle. This method can also be used for keypads where the keys are independently addressable, such as a keypad where each switch is a diode associated with it.

Fig. 8 shows the hardware structure for implementing the methods of Figs. 6 and 7. A readout line 26 has been added to measure the output of the combination key 22. The switch 21 dedicated to the input of those combination keys 22 is driven by the drive line 24 of the independent key 11. The input is provided to the combination key 22 using a bridge 31 that taps the signal from the drive line 24 of the individual key 11. The read line 26 leads to the processor 151. The electrical information on the drive line 24 can be read on the read line 26 to identify the switch of any combination key 22 or independent key 11. This information is preferably used in conjunction with the methods of FIGS. 6 and 7.

Figure 9 shows another PCB design, suitable for implementing the methods of Figures 6 and 7. In this example, the drive lines 24 labeled DR2, DR4, and DR6 directly feed the switch of the combination key 22.

10, the force exerted by the finger 55 is concentrated in its central area 34, this force is located at the crest of the curve and is concentrated under the bone. The force is transmitted through the central area 34, and the outside of the finger 55 is compliant around the raised key area 11. A partial depression 136 is formed between one side of the independent key 11 and the convex surface 38 of the combined key area 22. The partial depression 136 provides a tactile difference between the independent key 11 and the combination key 22.

FIG. 11 shows the finger 55 pressing the combination key 22. The convex shape 38 rests on the top of the combination key 22, giving a raised surface that meets the central area 34, but this rise is not as high as the independent key area 11, which must at least rise It is higher than the combination key area 22. This is because if the finger 55 is placed to trigger the combination key area 22 as shown in Figure 11, the fleshy finger 55 penetrates the keypad to a greater extent than placing the same finger as shown in Figure 10 to trigger the adjacent The independent key area 11 is deeper into the keypad. There is a recessed area 136 away from the central area 34 of the combination key 22, which separates the force of the fingers, thereby further concentrating the force in the central area 34 and helping to avoid dispersing the force to a larger area and adjacent independent keys 11 on. This increases the force transmission through the convex shape 38, allowing the finger 55 to trigger the combination key 22 (which includes a separate independently operable switch below to provide a very clear tactile response) while reducing the triggering of adjacent independent keys. 11 possibilities. The best relationship between the diameter of the independent key 11 and the diameter of the combined key 22 is approximately 1:2. However, the electronic device of FIG. 8 or 9 and the algorithm of FIG. 6 or 7 can allow one or more adjacent independent keys 11 to be triggered inadvertently, for example, due to inaccurate placement of fingers or excessively large fingers. Tactile feedback (preferably a very clear sensory feedback to a detected input) is an important aspect of any keypad. When the combination key 22 or the independent key 11 is pressed, these structures can provide a separate and clear tactile feedback in the IACK keypad.

FIG. 12 shows a finger pressing the combination key area 22, which has an effective flat shape 140. In addition, a separate independently operable switch under the key combination area provides a very clear tactile response.

Figure 13 shows a finger pressing the raised key area 11 of the keypad. The surface of the keypad in the keypad is basically flat. The individual keys 11 are distinguished by tactile elements 142 with clear contours such as rings or edges, and the combination The key 22 is concave.

Fig. 14 shows the keypad detached from the housing 90 of the related electronic device. The separated combination key 22 and the independent key 11 are bonded to the elastic sheet 41. In order to increase the reliability of the stable mechanical contact between the actuator 36 and the button dome 12, as shown in FIG. 15, the size of the manufactured elastic sheet 41 is smaller than that of the restricting element 143, so that the size of the At this time, the elastic sheet 41 is in a tensioned state. In other words, the elastic sheet 41 is assembled to the restricting element after being stretched (that is, in a tensioned state). This means that the distance between the restriction elements 143 across the housing is greater than the distance between the corresponding location features 49 in the sheet 41. But in one embodiment, the position of the key in the center (like the key in the middle here) is where they should be after assembly; the closer the key is to the edge, the closer to their position after installation. The keys are glued to the sheet 41, so once installed (and the sheet 41 is stretched), the keys are correctly positioned. The dimension "X" indicates the gap between adjacent keys before installation. Similarly, in one embodiment, the position of the actuator 36 or the metal dome 12 and the switch 48 of the dome is staggered (displaced) relative to the unassembled sheet 41, so that only after installation, it is printed on the PCB The actuator 36 on 23, the metal dome 12 and the switch 48 of the dome are aligned (as shown in Figure 15).

Referring to Figure 15, when the keypad is installed, "y" is used to indicate the gap between adjacent keys. At the edge of a typical keypad, the difference between "x" and "y" (the most affected key) is more than 20%, usually 20% to 80%. After installation, the key and actuator 36 are aligned with the switch 48. The size of the keypad is designed to be smaller than the opening in the housing 90. Another alternative method is to fix the key structure to the elastic sheet while the sheet is in a stretched state, so as to control the gap distance between the keys. When the elastic sheet 41a of the keypad of FIG. 16 is molded, it has wrinkles 47 or other elastic structures. For a given tension, they play a role in maintaining the tension in the elastic sheet in a wide temperature range. The distance between the restricting elements is greater than the distance between the corresponding position features 49 in the sheet 41, so that in the installed keypad, the fold 47 expands to a certain extent from its molded state.

Figure 17 shows an IACK keypad 10, including a plastic (very hard) mesh structure, about 0.5 to 1.0 mm thick, forming a continuous surface on the entire keypad area, which has holes, and the combination keys 22 pass through these The hole is exposed. The dotted area represents the range of the mesh structure 40. Since the net structure 40 is a plastic material, it can be made of the same material as the outer casing 90 of the product itself, and can be connected with the outer casing 90 of the product. This can provide important advantages in terms of design flexibility, aesthetics (due to the use of the same material, which eliminates the color matching of different materials and the need to use different tools for manufacturing), durability and cost. The tile structure is not used, so that the edges are eliminated, so that fiber materials such as sweaters will not be caught. The independent key 11 is given by a partial rise on the material of the mesh structure 40, and is triggered by the flexure of the hard plastic. The combination key 22 is a separate plastic (very hard) key located in a hole in the mesh structure 40. This has a sufficiently flexible and very hard small keyboard so that the user can feel the tactile feedback. It is also possible to provide additional grooves on the back side of the mesh structure to increase its flexibility. Preferably, the fluid plastic flows in a common direction during the manufacturing process. The transition area between the shell and the key pad can be made as thin as possible, or made of a material with lower hardness, such as polyurethane, so as to have extra flexibility on the edge of the key pad. Those relatively stationary parts (in this example, the independent keys 11 and the mesh structure 40) can be collectively referred to as panels of the keypad.

Referring again to FIG. 18, the combination key 22 includes a small (protruding) protrusion, or hillock, but its height is much lower than the height of the independent key 11. The independent key 11 is higher than the combined key 22 by about 0.25 to 0.75 mm. The overall height of the key from the lowermost surface of the actuator 36 to the highest surface above it makes the distribution of most of the force provided by the curvature of the user's finger (central area 34) (higher in the center, gradually decreasing toward the edge) suitable for combination The area of the key 22 includes the state after the button dome 12 has been triggered. In another embodiment, the independent key 11 and the combination key 22 have almost the same height. The discontinuous keys are held on the keypad 10 by elastic sheets 41. Although the mesh structure 40 is rigid, the overall structure can move relative to the PCB 23 and the mesh structure 40 can move relative to the combination key 22. This flexion/movement makes it possible to operate the IACK keypad with a rigid plastic surface.

FIG. 1 shows an example in which the combination key 22 and the mesh structure 40 are integrally molded together, and the individual keys 11 are not continuous. The relatively stationary part (in this example, the combination key 22 and the mesh structure 40) can be collectively referred to as the panel of the keypad 10. When the key combination 22 is pressed, the panel flexes.

Referring again to FIG. 20, the elliptical extension area of the combination key 22 is marked as "W" along its main axis. In this embodiment, compared with the embodiment of FIGS. 17 and 18, the extra width (outside the range of W) adjacent to the mesh structure 40 effectively increases the size of the combination key 22, thereby helping the designer to make the user's finger apply The distribution of the force does not trigger the raised key. It should also be noted that accidental triggering of the raised key 11 is acceptable because the only harm is the additional tactile feedback. The additional signals provided to the system will not cause problems. Although the net structure 40 is rigid, the overall structure can move relative to the PCB 23, and the net structure 40 can move relative to the independent key 11. This flexion/movement makes it possible to operate the IACK keypad with a rigid plastic panel. The discontinuous keys are held on the keypad 10 by the elastic sheet 41. By providing independent movement in both the independent key 11 and the combination key 22, as long as the mesh structure 40 is allowed to be at least as long as the key trigger stroke with low force deflection, the implementation of Figures 18 and 20 can also be implemented in the same product example.

With reference to Figures 21 and 22, the metal button dome 12 has a raised central area 212 that forms a downwardly facing cavity 13 defined at its rim by a geometric discontinuity 214 such as the ridge shown. The discontinuity 214 is placed on the at least two switch contacts 16, and the at least two switch contacts 16 are usually placed on the printed circuit board 23 electrically insulated from each other. The metal button dome 12 includes a rim 118 that rests on another electrically different switching element, which is the signal reference 224. The actuator 36 is placed to apply force to the raised central area 212 and thereby move it. It should be noted that the force applied by the actuator 36 is not transmitted down to the PCB 23 (below the center of the actuator 20), but transmitted by off-center material, in this example, the lower side of the discontinuity 214 located radially outside the center 17 of the actuator. In this way, the magnitude of the force applied by the actuator 36 does not act on a single point, but is distributed on a line, in this example a curve forming a circular contact area 230. The contact area 230 is approximately 1/3 of the nominal diameter of the metal dome 12, creating a "third" point or contact point (within the contact area 230) that is equidistant between the edges 118 and approximately equal to each other. Therefore, when one side of the discontinuity 214 contacts the first switching element 16, a torque is applied to the contact point, and the moment acts to force the other side of the discontinuity 214 to contact the second switching element 16. The purpose is to make two or more separate wires reliably connected to the common signal reference 224. The discontinuity 214 may be in the form of a downward annular recess, so that the raised central area 212 rises relative to the lower edge of the discontinuity 214 but is not separated from the rest of the button dome 12.

As shown in FIG. 22, the dome contacts three switching elements 16 along the contact area 230. The signal reference 224 serves as the fourth element. Via 32 connects switching element 16 to traces on the lower layer of the PCB. Each switching element 16 extends within an angle α, in this example α is approximately 20 degrees, which adds up to approximately 1/6 of the circumference of the contact area 230 formed by the switching element 16. By making the contact with one or two switching elements 16 into an unstable structure, reducing the value of α contributes to the purpose of the principle of operation explained in FIG. 21. Therefore even if two contacts have been established, the force applied to the central axis 17 will apply an increased moment to help establish the contact between the metal dome 10 and each switching element 16. The instability provided by the contact button dome 12, the increased local pressure through the torque provided near the contact trip point and the narrowing of the trace, are all foreseeable potential advantages of this method. Note that three switching elements 16 are shown, two (and a smaller range of four) switching elements 16 can also benefit from this design. As shown in FIG. 23, the discontinuity 214 may be formed as a ring having a divided ridge portion, and the length and gap of the ridge are selected to facilitate reliable contact with each switching element 16.

Further features of the keypad structure can be found in the following US patent applications: serial number 60/382,906 filed on May 23, 2002; serial number 60/419,843 filed on October 21, 2002; December 9, 2002 The serial number submitted on February 3, 2003 is 60/431,796; the serial number submitted on February 3, 2003 is 60/444,227, and their content is hereby incorporated as a reference.

Some embodiments of the invention have been described. However, it should be understood that various modifications can be made without departing from the spirit and scope of the present invention. Therefore, other embodiments are within the scope of the appended claims.