Patent Publication Number: US-2011055697-A1

Title: Alphanumeric keypad for touch-screen devices

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE 
     This application claims priority to U.S. Application Ser. No. 61/237,182 filed Aug. 26, 2010, which is incorporated by reference herein in its entirety. 
    
    
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     [Not Applicable] 
     MICROFICHE/COPYRIGHT REFERENCE 
     [Not Applicable] 
     FIELD OF THE INVENTION 
     The present invention relates generally to touch-screen electronic devices and systems, such as cell phones, smart phones, calculators, handheld scanners, gaming systems, remote controls, GPS navigation devices, and ultra small laptop computers. More particularly, the invention relates to a touch-screen keypad for data entry into such systems. 
     BACKGROUND OF THE INVENTION 
     As touch-screen electronic devices continue to be reduced in size, device manufacturers are increasingly challenged with designing alphanumeric keypads that are small yet accurate and easy to use. Typically these devices display  26  distinct buttons (one for each letter in the alphabet) in an area that is about 1200 sq. mm—thus, the surface area allocated to each button is less than 50 sq. mm. The buttons are typically arranged in rows and/or columns with minimal spacing between adjacent buttons. 
     Given the large number of small, closely spaced buttons, accurate entry of alphanumeric characters can be difficult—particularly for those with large hands or those who have difficulty reading small type. 
     Furthermore, since touch-screens do not provide tactile feedback, it is very difficult to input text without visually verifying whether each letter has been correctly selected. Similarly, it is difficult to accurately enter a phone number on a numeric keypad without visual verification—even though the keys are typically much larger. 
     It is therefore, an object of the present invention to improve the accuracy and ease of entering alphanumeric characters into touch-screen devices both with and without visual verification. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the invention is achieved via two design methods: 
     1. The use of a multi-function button that allows entry of multiple distinct characters. This multi-function button visually presents a primary key and one or more additional keys formed in subtending portions. Each button represents two or more alphanumeric characters. 
     2. The deterministic actuation of multiple distinct buttons in sequence as the user slides a finger across multiple buttons. More specifically, an actuated button can be either adjacent or non-adjacent to the previously actuated button. 
     One embodiment of the present invention is an alphanumeric keypad for a touch-screen smart phone such as an Apple iPhone phone. A second embodiment of the invention is a numeric keypad for dialing phone numbers on a touch-screen phone. 
     The first embodiment—an alphanumeric keypad—comprises a modification to the QWERTY keypad layout that organizes letters according to the frequency of letter usage. More specifically, letters are placed to allow selection of the most frequently used letters just by touching the touch-screen display and selection of less frequently used letters by sliding a finger to a subtending portion of a key. 
     In this embodiment, a specialized software algorithm will be used to accurately detect entry of each alphanumeric character that is displayed. It is envisioned that typical applications for this embodiment would be smart phone devices such as the iPhone phone or Blackberry Storm device and portable navigation devices such as a Garmin device. 
     In this embodiment, a touch sensitive display screen would consist of both single-function buttons and multi-function buttons. Each multi-function button visually indicates a primary key, which is selected by touching, and a second key formed as a subtending portion, which is selected by sliding down to the subtending portions. 
     This keypad comprises sixteen (16) single-function buttons and six (6) multi-function buttons to enter one of 28 characters (26 letters plus two punctuation marks). 
     This keypad consists of only six (6) buttons per row versus typical touch-screen keypads, which have nine (9) to ten (10) buttons on each row. Thus, the buttons in this embodiment are much wider than typical touch-screen keypads. 
     The second embodiment—a numeric keypad—comprises twelve (12) single function buttons (the numbers 0 to 9, *, and #) arranged in 4 rows as is typically done on current numeric touch-screen keypads. The present invention differs from current designs, since multiple numbers can be entered in sequence by sliding from one key to adjacent or non-adjacent keys. 
     BENEFITS OF THE INVENTION 
     The key benefits of the present invention are:
         a. The width of each button is much greater.   b. The alphanumeric labels on the buttons are more readable.   c. The user can select and enter characters more accurately, especially with one hand.   d. The user can enter numbers or letters with less visual verification.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the primary display of a keypad embodiment of the present invention having a modified QWERTY layout on a touch-screen device such as the Apple iPhone phone. 
         FIG. 2  shows a secondary display of the keypad embodiment for entry of numeric and special characters. 
         FIG. 3  shows a comparison of the keypad of  FIG. 1  and a traditional QWERTY keypad layout on a touch-screen device such as the Apple iPhone phone. 
         FIG. 4  shows user actuation for selection of the letter (F) and the letter (I)—which are frequently used letters—on the keypad of  FIG. 1 . 
         FIG. 5  shows user actuation for selection of a letter (X)—which is an infrequently used letter—on the keypad of  FIG. 1 . 
         FIG. 6  shows user actuation of the letters (U) and (P) sequentially by sliding a finger between adjacent buttons on the keypad of  FIG. 1 . 
         FIG. 7  shows user actuation of the letters (T) and (0) sequentially by sliding a finger between non-adjacent buttons on the keypad of  FIG. 1 . 
         FIG. 8  shows user actuation of the letters (H), (I), and (T) sequentially by sliding to a second button—then changing the sliding direction to a third button on the keypad of  FIG. 1 . 
         FIG. 9  shows user actuation of the letters (P), (I), and (N) sequentially by sliding diagonally between multiple buttons. 
         FIG. 10  shows user actuation of numbers and characters on the secondary display of  FIG. 2 . 
         FIG. 11  shows user actuation of the numbers (2), (8), and (9) sequentially by sliding between multiple buttons on a numeric keypad that is used to dial phone numbers. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to Table 1, an important aspect of the design is the incorporation into the design of the frequency of letter usage in the English language. In this embodiment, the primary letters are used of 99% of the time—and thus can be selected more easily and rapidly with a typical touch contact with the screen. The second letters require an additional sliding movement—but since they are rarely selected—do not impact the speed of entering text. Also referring to Table 1, the top and bottom rows—Row 1 and Row 2 contain less frequently used letters, which facilitates the entry of multiple sequential letters. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Touch 
                   
                 Slide 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 W 
                 1.9% 
                   
                   
               
               
                   
                 Y 
                 1.7% 
               
               
                   
                 U 
                 2.7% 
               
               
                   
                 P 
                 2.0% 
               
               
                   
                 Row 1 
                 8.4% 
               
               
                   
                 E 
                 12.5% 
               
               
                   
                 R 
                 6.1% 
               
               
                   
                 T 
                 9.3% 
               
               
                   
                 I 
                 7.3% 
               
               
                   
                 O 
                 7.6% 
               
               
                   
                 L 
                 4.1% 
               
               
                   
                 Row 2 
                 46.9% 
               
               
                   
                 A 
                 8.0% 
               
               
                   
                 S 
                 6.5% 
               
               
                   
                 D 
                 4.0% 
               
               
                   
                 H 
                 5.5% 
               
               
                   
                 N 
                 7.1% 
               
               
                   
                 M 
                 2.5% 
               
               
                   
                 Row 3 
                 33.7% 
               
               
                   
                 C 
                 3.1% 
                 Q 
                 0.1% 
               
               
                   
                 F 
                 2.3% 
                 Z 
                 0.1% 
               
               
                   
                 G 
                 2.0% 
                 X 
                 0.2% 
               
               
                   
                 V 
                 1.0% 
                 J 
                 0.2% 
               
               
                   
                 B 
                 1.5% 
               
               
                   
                 K 
                 0.7% 
                   
               
               
                   
                 Row 4 
                 10.5% 
                   
                 0.6% 
               
               
                   
                 Total 
                 99.4% 
                   
                 0.6% 
               
               
                   
                   
               
            
           
         
       
     
     
       
         
           
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
             
            
               
                   
                 Letter Frequency in the English Language 
               
               
                   
                 e t a o i n s r h l d c u m f p g w y b v k x j q z 
               
               
                   
                 Letter Frequency of the Most Common 1st Letter in Words 
               
               
                   
                 t o a w b c d s f m r h i y e g l n p u j k 
               
               
                   
                 Letter Frequency of the Most Common 2nd Letter in Words 
               
               
                   
                 h o e i a u n r t 
               
               
                   
                 Letter Frequency of the Most Common 3rd Letter in Words 
               
               
                   
                 e s a r n i 
               
               
                   
                 Letter Frequency of the Most Common Last Letter in Words 
               
               
                   
                 e s t d n r y f l o g h a k m p u w 
               
               
                   
                 More than half of all words end with: e t d s 
               
               
                   
                 e s t d n r y o f g a l h m u k i w p c x b z v j q 
               
               
                   
                 Digraph Frequency 
               
               
                   
                 th he an in er on re ed nd ha at en es of nt ea ti to io le is ou 
               
               
                   
                 ar as de rt ve 
               
               
                   
                 Trigraph Frequency 
               
               
                   
                 the and tha ent ion tio for nde has nce tis oft men 
               
               
                   
                 Word Frequency for the Most Common Words 
               
               
                   
                 the of and to in a is that be it by are for was as he with on his 
               
               
                   
                 at which but from has this will one have not were or all their 
               
               
                   
                 an i there been many more so when had may today who would 
               
               
                   
                 time we about after dollars if my other some them being its no 
               
               
                   
                 only over very you into most than they day even made out first 
               
               
                   
                 great must these can days every found general her here last 
               
               
                   
                 new now people public said since still such through under up 
               
               
                   
                 war well where while years before between country debts 
               
               
                   
                 good him interest large like make our take upon what 
               
               
                   
                   
               
            
           
         
       
     
     Referring to Table 2, the example embodiment also relies on other letter usage statistics (e.g., common words, diagraphs frequency, etc.) to optimally arrange letters for maximum speed and accuracy of text entry. 
     Referring to  FIG. 1 , a touch screen phone  101  includes a touch screen display  103  having a touch-operated keypad  105 . Keypad  105  graphically displays sixteen (16) single-function buttons  111  and six (6) multi-function buttons  121  that are used to enter one of twenty-eight (28) alphanumeric characters (twenty-six letters plus two punctuation marks) into device  101 . Each single-function button  111  and each multi-function button  121  is a discrete rectangular area of the touch display  103 . 
     Button  121  has a primary key  123  and a secondary key  125 . Primary key  123  is located as the upper portion of the rectangular area of button  121 , for example, the top one-half of the rectangular area, and visually presents a primary alphabet character to be entered by dual-function button  121 . Secondary key  125  is located as the lower portion of the rectangular area of button  121 , for example, the bottom one-half of the rectangular area, and visually presents a secondary alphabet character to be entered by dual-function button  121 . 
     A primary key  123  is actuated by touching anywhere on the entire button  121  and then releasing contact. The secondary key  125  is actuated by touching anywhere on button  121 , and then sliding downward, and then releasing contact. 
     The specialized software algorithm that is used to determine the selected letter for a button  121  is as follows: 
     1. If the starting touch-point and ending touch-point are equal (within a defined margin of error), the actuation is defined as a “touch” motion and one of the six primary letters are selected (i.e., C, F, G, V, B, or K). 
     2. If the starting touch-point and ending touch-point are different (greater than the margin of error), the distance travelled horizontally (x-axis) and vertically (y-axis) is computed. 
     3. If the ending point is vertically below the starting point, the secondary character in the lower subtending portion of the button  121  is selected (i.e., Q, Z, X, J, comma, or period). 
     Referring to  FIG. 2 , a secondary display of the keypad for entering numbers and special characters is shown. A user can alternate between the primary display in  FIG. 1  and the secondary display of  FIG. 2  by actuating button  131 , which is on both the primary and secondary displays. 
     The present invention has been implemented as an iPhone Application using Xcode Version 3.2.2 and iPhone Software Development Kit (SDK) Version 3.1.3 Printed Copies of the four C-Code files that were written for said iPhone Application implementation are filed herewith as Exhibits A, B, C, and D incorporated herein by reference. As will suggest itself, other software may be used to implement the present invention on other specific phones and types of devices. 
       FIG. 3  shows a comparison of an embodiment of the present invention at  101  with the current state of the art that is available on the iPhone at  301 . 
     Referring to  FIG. 4 , screenshots  401 ,  403  show the selection of a primary letter “F” using a multi-function button  121  ( FIG. 1 ). In screenshot  401 , the button  121  is touched (contacted) and a “pop-up” display  411  of the letter “F” appears above the touched button on the display  103 , as shown. In screen shot  403 , the touch contact is removed and pop-up  411  is removed and the letter “F” is added to the display as text in the display area above keypad  105 . Similarly in screenshots  405  and  407 , selection of the letter “I” on a single-function button  111  ( FIG. 1 ) is shown. 
     Referring to  FIG. 5 , screenshots  501 ,  503  and  505  show the selection of a lower letter on a multi-function button  121  ( FIG. 1 ). In screenshot  501 , a multi-function button  121  is touched so that a “pop-up” display  511  with the letter “g” occurs above the touched button on the display  103 , as shown. In screenshot  503 , the user maintains contact with button  121  and with a sliding motion moves a finger down to the lower portion, i.e., the secondary key  125 , of button  121 . The pop-up  511  is removed and a new popup display  513  with the letter “X” appears on the screen above the touched button. In screenshot  505 , the touch contact is removed, pop-up display  513  is removed and the letter “Y” is added to the display as text in the display area above keypad  105 . As shown in screen shots  501 ,  503 , the first pop-up  511  and the second pop-up  513  are highlighted with a different color, e.g., pop-up  511  is white and pop-up  513  is red, to provide confirmation to the user that the secondary character will be entered. 
     Referring to  FIG. 6 , screenshots  601 ,  603 , and  605  show sequential entry of multiple letters by sliding from a first button  111  to a second adjacent button  111 . In screenshot  601 , a single-function button  111  is touched (contacted) and a “pop-up” display  611  with the letter “U” appears on the screen. In screenshot  603 , the user maintains contact with the “U” button  111  and then with a sliding motion moves a finger laterally to the adjacent button, the “P” button  111 . In response to this sliding action between two buttons  111 , the pop-up display  611  is removed; the letter “U” is added as text; and a new pop-up display  613  with the letter “P” appears on the screen. In screenshot  605 , the touch contact is removed from the “P” button, the pop-up display is removed and the letter “P” is added to the display as text. As shown in screenshots  603  and  605 , the first button  111  contacted and the adjacent button  111  are highlighted with a color (e.g., green) different than the original color of the buttons (e.g., white) during a multi-button sequence to provide confirmation to the user that multiple letters will be entered. 
     Referring to  FIG. 7 , screenshots  701 ,  703 , and  705  show sequential entry of multiple letters by sliding from a first button to a second non-adjacent button. In screenshot  701 , a single-function button  111  is touched (contacted) and a “pop-up” display  711  with the letter “T” appears on the screen. In screenshot  703 , the user maintains contact with button  111  and then with a sliding motion moves a finger laterally across the adjacent button and to a non-adjacent button  111 , where the finger stops but remains in contact with the non-adjacent button  111 . The pop-up display  711  is removed; the letter “T” is added as text; and a new popup display with the letter “O” appears on the screen. In screenshot  705 , the touch contact is removed from the “O” button, the pop-up display  713  is removed and the letter “O” is added to the display as text. The buttons (“T” and “O”) remain green highlighted momentarily, e.g., 300 milliseconds, and then the green highlighting is removed. This provides visual feedback to the user that those letters were successfully entered. An important aspect of this invention is the determination of whether to actuate an intermediate button—in this case button  111  with the letter “I”—since it is contacted as the finger moves to the non-adjacent button. A number of different selection criteria can be implemented by those skilled in the art to accurately detect non-selection of intermediate buttons. In this embodiment, two methods are implemented concurrently to determine if intermediate buttons should be activated: 
     1. The instantaneous speed of the finger is continuously monitored and if the speed at the time of contact of the intermediate button drops below a pre-determined threshold—the intermediate button is activated. 
     2. The instantaneous direction of the finger movement is continuously monitored (i.e., via well known mathematical formulas applied to the change in X &amp; Y coordinates). If a differential direction is above a pre-determined threshold at the time of contact of the intermediate button,—the intermediate button is selected. In this embodiment, direction is measured in degrees between 0 and 360 degrees with a threshold of 25 degrees. 
     Referring to  FIG. 8 , screenshots  801 ,  803 , and  805  show actuation of three buttons in sequence in which a change in direction is detected. As seen from screenshots  801  and  803 , the initial direction of the finger movement is 360 degrees (vertically up), beginning at the button for the letter “H” and moving to the button for the letter “I”. In screenshot  805 , the direction of movement changes to 270 degrees (horizontally to the left) moving from the button for the letter I to the button for the letter “T”. Since the direction change is 90 degrees, which is greater than the 25 degrees, the intermediate button for the letter “I” is actuated. If the movement would have continued vertically up to the button for the letter “U”, the letter “I” would not have been entered. 
     Similarly in  FIG. 9 , the same principle of direction change can be applied to diagonally adjacent buttons as well. 
     Referring to  FIG. 10 , the same methods shown in  FIGS. 7 ,  8 , and  9  are applied to the secondary display that is used for numbers and other characters. 
     Referring to  FIG. 11 , a second embodiment—a numeric keypad for entering phone numbers—is shown. The same principles as described for the alphanumeric keypad are implemented as shown in screenshots  1101 ,  1103 ,  1105 . In this embodiment, the user can subsequently place a telephone call by pressing the “Call” button. 
     A distinct novelty of the present invention is the deterministic actuation of multiple sequential buttons via pre-defined thresholds. Deterministic actuation solves a long-standing problem that has plagued prior-art implementations text entry via finger movements on touch-screen devices. Since the prior art was not deterministic, complex and inaccurate methods such as dictionary look-ups to “predict” button actuation was necessary. In addition, the present invention allows entry of partial words by sequential button actuation—which is not possible with the prior art. 
     As detailed in this application and its associated figures, the use of multi-function buttons and multiple, sequential button actuations are clear advances over the known art for alphanumeric character entry in touch-screen devices. In addition, the proposed invention can be cost effectively reduced to practice using appropriate adaptations of current software and hardware design techniques.