Abstract:
Depressible home keys built into an overlay for a touch-sensitive keyboard offer rest positions for the fingers of a typist, and recesses in the overlay allow engagement of the touch sensor while providing tactile feedback to the typist when engaging non-home keys. The significant difference in elevation between the recesses and the rest of the overlay prevents accidental engagement of spaces between the keys or of multiple keys at one time. This configuration for touch-sensitive keyboards can be embodied in an overlay for a touch screen or for a tablet computer, as a stand alone keyboard, or as a stand alone keyboard that includes a touch screen that provides multiple sets of characters and/or commands to be used with specific computer programs.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to providing tactile feedback for all keys on a touch-sensitive keyboard. 
         [0002]    Numerous embodiments of touch-sensitive keyboards exist in the prior art including ones that provide means by which the typist can push depressible keys to provide tactile point of reference and tactile feedback, including U.S. Patent Application # 20130002584 A1, U.S. Pat. No. 8,692,783 B2, U.S. Pat. No. 8,558,796 B2, U.S. Pat. No. 8,243,038, U.S. Pat. No. 6,880,998, U.S. Pat. No. 7,659,885, U.S. Pat. No. 7,403,191, U.S. Patent Application # 20100238119 A1, and U.S. Pat. No. 8,206,047 B1. However, none of these keyboards take advantage of the lighter touch that touch-sensitive surfaces and touch screens afford, and instead force the user to push every key. Furthermore, none of these solutions prevent the inadvertent engagement of multiple keys. 
         [0003]    Other embodiments of touch-sensitive keyboards exist in the prior art that include overlays with recesses or holes in the overlay positioned above the keys of the keyboard, as in U.S. Pat. No. 8,692,783 and U.S. Patent Application # 20130079139 A1, but such embodiments require the user to keep his or her hands elevated above the overlay, because they do not provide rest positions for the fingers. 
         [0004]    My U.S. Pat. No. 6,869,289 introduced the concept of depressible keys in the home row in an otherwise touch-sensitive keyboard. The current patent application extends that principle by uniquely addressing the need for tactile feedback for all keys and the need to prevent inadvertent multi-key strikes. 
         [0005]    It would be advantageous to provide an overlay for touch-sensitive keyboards, including touch screens, that incorporates depressible home keys allowing users to rest their fingers and maintain an overall tactile sense of the keyboard&#39;s placement and incorporates depressions in the overlay for all other keys. These depressions allow engagement of the touch-sensitive surface below the overlay and provide tactile feedback as the user engages all non-home keys. In this way, we take advantage of the lighter touch we have come to expect from touch screens, while maintaining overall sensory awareness of all keys, allowing typists to touch type without looking at the keys. Furthermore, the raised elevation of the overlay where there are no depressions prevents accidental engagement of spaces between the keys or of multiple keys at one time. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    It is an object of the invention to provide a tactile overlay for a touch-sensitive keyboard including eight depressible home keys for the fingers and depressions in the overlay for all non-depressible keys. The overlay prevents engagement of the touch-sensitive keyboard where there are no depressions or depressible keys in the overlay and prevents the accidental engagement of multiple keys at one time. 
         [0007]    It is a further object of the invention to provide a modified form of construction which includes a transparent tactile overlay for a touch-sensitive screen that provides eight depressible transparent dome home keys for the fingers, two depressible transparent dome home keys for the thumb, and depressions in the overlay for all non-depressible keys. Ends of the overlay with a micro-suction bottom surface keep the overlay in position over the onscreen virtual keyboard. The overlay prevents engagement of the touch-sensitive screen where there are no depressions or depressible keys in the overlay and prevents the accidental engagement of multiple keys at one time. 
         [0008]    It is a further object of the invention to provide a modified form of construction which includes a transparent tactile overlay for the touch-sensitive screen of a tablet computer that provides eight depressible transparent dome home keys for the fingers, one depressible transparent elongated dome home key for the thumbs, and depressions in the overlay for all non-depressible keys. In this form of construction, the left and right halves of the overlay are set at an oblique angle relative to one another. The overlay prevents engagement of the touch-sensitive screen where there are no depressions or depressible keys in the overlay and prevents the accidental engagement of multiple keys at one time. The edges of the overlay are formed to bend around the edges of the tablet computer to keep the overlay in position on the tablet computer. 
         [0009]    It is a further object of the invention to provide a modified form of construction which includes a transparent tactile overlay for the touch-sensitive screen of a smart phone that provides four depressible transparent dome home keys for the fingers, one depressible transparent dome home key for a thumb, and depressions in the overlay for all non-depressible keys. The overlay prevents engagement of the touch-sensitive screen where there are no depressions or depressible keys in the overlay and prevents the accidental engagement of multiple keys at one time. The edges of the overlay are formed to bend around the edges of the smart phone to keep the overlay in position on the smart phone. 
         [0010]    It is a further object of the invention to provide a modified form of construction which includes a keyboard that has a convexly arced shape with the left and right halves of the keys spatially separated from one another to make room for a 3D sensor built into the middle of the keyboard. 
         [0011]    It is a further object of the invention to provide a modified form of construction which includes an inflatable and deflatable tactile overlay that is permanently attached to a touch screen, providing eight depressible home keys for the fingers, two depressible home key for the thumbs, depressions in the overlay for all non-home keys, and a raised surface surrounding all keys. The raised surface surrounding all keys, the sloping sides of the depressions, and the raised and depressible home keys all can be deflated to lay flat against the touch screen. The overlay prevents engagement of the touch screen where there are no depressions or depressible keys in the overlay and prevents the accidental engagement of multiple keys at one time. 
         [0012]    It is a further object of the invention to provide a modified form of construction which includes a transparent tactile overlay for a tablet computer that provides eight depressible transparent dome home keys for the fingers, two depressible transparent dome home keys for the thumbs, and depressions in the overlay for all non-depressible keys. In this form of construction, the overlay is built into a removable screen cover for the tablet computer. The overlay prevents engagement of the tablet&#39;s touch screen where there are no depressions or depressible keys in the overlay and prevents the accidental engagement of multiple keys at one time. 
         [0013]    It is a further object of the invention to provide a modified form of construction which includes a transparent tactile overlay that provides eight depressible transparent dome home keys for the fingers, two depressible transparent dome home keys for the thumbs, and depressions in the overlay for all non-depressible keys. This transparent tactile overlay is permanently affixed to a touch sensitive screen built into the horizontal portion of a laptop computer. Variable sets of characters and commands can be chosen to appear on the horizontal touch sensitive screen so it can be used as a data input keyboard for various programs running on the laptop computer. The overlay prevents engagement of the touch-sensitive screen where there are no depressions or depressible keys in the overlay and prevents the accidental engagement of multiple keys at one time. 
         [0014]    It is a further object of the invention to provide a modified form of construction that includes a tactile overlay for a touch-sensitive keyboard that provides eight depressible dome home keys for the fingers, one depressible elongated dome home key for the thumbs, and depressions in the overlay for all non-depressible keys. In this form of construction, the left and right halves of the keys are set at an oblique angle relative to one another and are separated to make room for an elevated touch-sensitive platform. The overlay prevents engagement of the touch-sensitive screen where there are no depressions or depressible keys in the overlay and prevents the accidental engagement of multiple keys at one time. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0015]    The present invention will be more fully understood by reference to the following detailed descriptions thereof when read in conjunction with the attached drawings, and wherein: 
           [0016]      FIG. 1  is a perspective view of a preferred embodiment of the keyboard in accordance with the present invention in which a tactile overlay for a touch-sensitive keyboard includes eight depressible home keys for the fingers and depressions in the overlay for all non-depressible keys; and 
           [0017]      FIG. 2  is a perspective view of a modified form of construction of the keyboard in accordance with the present invention in which a transparent tactile overlay for a touch-sensitive screen provides eight depressible transparent dome home keys for the fingers, two depressible transparent dome home keys for the thumbs, and depressions in the overlay for all non-depressible keys. Ends of the overlay with a micro-suction bottom surface keep the overlay in position over the onscreen virtual keyboard; and 
           [0018]      FIG. 3  is a perspective view of a further modified form of construction of the keyboard in accordance with the present invention in which a transparent tactile overlay for the touch-sensitive screen of a tablet computer provides eight depressible transparent dome home keys for the fingers, one depressible transparent elongated dome home key for the thumbs, and depressions in the overlay for all non-depressible keys. In this form of construction, the left and right halves of the overlay are set at an oblique angle relative to one another. The edges of the overlay are formed to bend around the edges of the tablet computer to keep the overlay in position on the tablet computer; and 
           [0019]      FIG. 4  is a perspective view of a still further modified form of construction of the keyboard in accordance with the present invention in which a transparent tactile overlay for the touch-sensitive screen of a smart phone provides four depressible transparent dome home keys for the fingers, one depressible transparent dome home key for a thumb, and depressions in the overlay for all non-depressible keys. The edges of the overlay are formed to bend around the edges of the smart phone to keep the overlay in position on the smart phone, and 
           [0020]      FIG. 5  is a perspective view of an even still further modified form of construction of the keyboard in accordance with the present invention in which the keyboard has a convexly arced shape with the left and right halves of the keys spatially separated from one another to make room for a 3D sensor built into the middle of the keyboard that can track the motion of the fingers and hands of a user in the space above said touch screen for the purpose of providing interactive control in mid-air of a computerized device; and 
           [0021]      FIG. 6  is a perspective view of an even yet still further modified form of construction of the keyboard in accordance with the present invention in which an inflatable and deflatable tactile overlay is permanently attached to a touch screen, providing eight depressible home keys for the fingers, two depressible home key for the thumbs, and depressions in the overlay for all non-home keys. The raised surface surrounding all keys and the raised and depressible home keys all can be deflated to lay flat against the touch screen; and 
           [0022]      FIG. 7  is a perspective view of the form of construction of the keyboard shown in  FIG. 6  in which the inflatable and deflatable tactile overlay is shown deflated. The raised surface of the tactile overlay surrounding all keys as well as the dome home keys are shown deflated to lay flat against the touch-sensitive screen; and 
           [0023]      FIG. 8  is a perspective view of a even yet further still modified form of construction of the keyboard in accordance with the present invention in which a transparent tactile overlay for a tablet computer provides eight depressible transparent dome home keys for the fingers, two depressible transparent dome home keys for the thumbs, and depressions in the overlay for all non-depressible keys. In this form of construction, the overlay is built into a removable screen cover for the tablet computer; and 
           [0024]      FIG. 9  is a perspective view of a even further modified form of construction of the keyboard in accordance with the present invention in which a transparent tactile overlay provides eight depressible transparent dome home keys for the fingers, one depressible transparent dome home key for a thumb, and depressions in the overlay for all non-depressible keys, including an elongated depression in the overlay for a non-depressible touch-sensitive key for a thumb that allows a thumb of the typist to move back and forth across its elongated depressed surface to scroll through and select alternate sets of data input commands that then appear on the touch-sensitive screen. The transparent tactile overlay is permanently affixed to a touch sensitive screen built into the horizontal portion of a laptop computer. Variable sets of characters and commands can be chosen to appear on the horizontal touch sensitive screen so it can be used as a data input keyboard for various programs running on the laptop computer; and 
           [0025]      FIG. 10  is a perspective view of a yet even still further modified form of construction of the keyboard in accordance with the present invention in which a tactile overlay for the keyboard provides eight depressible dome home keys for the fingers, one depressible elongated dome home key for the thumbs, and depressions in the overlay for all non-depressible keys. In this form of construction, the left and right halves of the overlay are set at an oblique angle relative to one another and are separated to make room for an elevated touch-sensitive platform. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    In  FIG. 1 , there is shown a perspective view of a preferred embodiment of the keyboard in accordance with the present invention in which a tactile overlay  1  for a touch-sensitive keyboard  2  includes eight depressible home keys for the fingers  3  and depressions in the overlay  1  for all non-depressible keys  4 . The tactile overlay  1  prevents engagement of the touch-sensitive keyboard  2  where there are no depressions or depressible keys in the tactile overlay  1  and prevents the accidental engagement of multiple keys at one time. Many different approaches could be taken to achieve satisfactory results in the production of the tactile overlay  1 , including the following: Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch sensor except where the non-depressible keys  4  are, and has holes where the dome shaped depressible home keys  3  are, and has thin sheet(s) of thermoformed flexible plastic that form the dome shaped depressible home keys  3 . Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch sensor except where the non-depressible keys  4  are, with holes where the dome shaped depressible home keys  3  are, and with silicone dome depressible home keys  3 . Thermoformed flexible plastic like HDPE that creates an air gap between the plastic and the touch sensor except where the keys are. Machined plastic thick enough to prevent engagement of the touch sensor, with holes machined out for all keys, and with thin sheet(s) of thermoformed flexible plastic for dome shaped depressible home keys  3 . Machined plastic thick enough to prevent engagement of the touch sensor, with holes machined out for all keys, and with silicone dome depressible home keys  3 . Injection-molded plastic thick enough to prevent engagement of the touch sensor except where the keys are, with silicone dome depressible home keys  3 . Injection-molded plastic thick enough to prevent engagement of the touch sensor except where the keys are, with holes left for all keys, and with a secondary thin sheet of thermoformed flexible plastic for dome shaped depressible home keys  3 . However, it cannot be said that there is one best method for achieving the overlay  1  as all of these approaches have their benefits and drawbacks; and 
         [0027]    In  FIG. 2 , there is shown a perspective view of a modified form of construction of the keyboard in accordance with the present invention in which a transparent tactile overlay  5  for a touch-sensitive screen  6  provides eight depressible transparent home keys for the fingers  7 , two depressible transparent home keys for the thumbs  8 , and depressions in the overlay  5  for all non-depressible keys  4 . The tactile overlay  5  prevents engagement of the touch-sensitive screen  6  where there are no depressions or depressible keys in the tactile overlay  5  and prevents the accidental engagement of multiple keys at one time. Ends of the overlay with a micro-suction bottom surface  9  keep the transparent tactile overlay  5  in position on the touch-sensitive screen  6 . Many different approaches could be taken to achieve satisfactory results in the production of the tactile overlay  5 , including the following: Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch-sensitive screen  6  except where the non-depressible keys  4  are, and has holes where the dome shaped depressible home keys  7  and  8  are, and has thin sheet(s) of thermoformed flexible plastic that form the dome shaped depressible home keys  7  and  8 . Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch-sensitive screen  6  except where the non-depressible keys  4  are, with holes where the dome shaped depressible home keys  7  and  8  are, and with silicone dome depressible home keys  7  and  8 . Thermoformed flexible plastic like HDPE that creates an air gap between the plastic and the touch-sensitive screen  6  except where the keys are. Machined plastic thick enough to prevent engagement of the touch-sensitive screen  6 , with holes machined out for all keys, and with thin sheet(s) of thermoformed flexible plastic for dome shaped depressible home keys  7  and  8 . Machined plastic thick enough to prevent engagement of the touch-sensitive screen  6 , with holes machined out for all keys, and with silicone dome depressible home keys  7  and  8 . Injection-molded plastic thick enough to prevent engagement of the touch-sensitive screen  6  except where the keys are, with silicone dome depressible home keys  7  and  8 . Injection-molded plastic thick enough to prevent engagement of the touch-sensitive screen  6  except where the keys are, with holes left for all keys, and with a secondary thin sheet of thermoformed flexible plastic for dome shaped depressible home keys  7  and  8 . However, it cannot be said that there is one best method for achieving the overlay  5  as all of these approaches have their benefits and drawbacks; and 
         [0028]    In  FIG. 3 , there is shown a perspective view of a further modified form of construction of the keyboard in accordance with the present invention in which a transparent tactile overlay  5  for the touch-sensitive screen  6  of a tablet computer  10  provides eight depressible transparent home keys for the fingers  7 , one depressible transparent elongated home key for the thumbs  11 , depressions in the overlay for all non-depressible keys  4 , and six depressible transparent command keys  12 . In this form of construction, the left and right halves of the keys are set at an oblique angle relative to one another. The tactile overlay  5  prevents engagement of the touch-sensitive screen  6  where there are no depressions or depressible keys in the transparent tactile overlay  5  and prevents the accidental engagement of multiple keys at one time. The edges  13  of the transparent tactile overlay  5  are formed to bend around the edges of the tablet computer  10  to keep the transparent tactile overlay  5  in position on the tablet computer  10 . Many different approaches could be taken to achieve satisfactory results in the production of the tactile overlay  5 , including the following: Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch-sensitive screen  6  except where the non-depressible keys  4  are, and has holes where the dome shaped depressible keys  7 ,  11 , and  12  are, and has thin sheet(s) of thermoformed flexible plastic that form the dome shaped depressible keys  7 ,  11 , and  12 . Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch-sensitive screen  6  except where the non-depressible keys  4  are, with holes where the dome shaped depressible keys  7 ,  11 , and  12  are, and with silicone dome depressible keys  7 ,  11 , and  12 . Thermoformed flexible plastic like HDPE that creates an air gap between the plastic and the touch-sensitive screen  6  except where the keys are. Machined plastic thick enough to prevent engagement of the touch-sensitive screen  6 , with holes machined out for all keys, and with thin sheet(s) of thermoformed flexible plastic for dome shaped depressible keys  7 ,  11 , and  12 . Machined plastic thick enough to prevent engagement of the touch-sensitive screen  6 , with holes machined out for all keys, and with silicone dome depressible keys  7 ,  11 , and  12 . Injection-molded plastic thick enough to prevent engagement of the touch-sensitive screen  6  except where the keys are, with silicone dome keys  7 ,  11 , and  12 . Injection-molded plastic thick enough to prevent engagement of the touch-sensitive screen  6  except where the keys are, with holes left for all keys, and with a secondary thin sheet of thermoformed flexible plastic for dome shaped depressible keys  7 ,  11 , and  12 . However, it cannot be said that there is one best method for achieving the overlay  5  as all of these approaches have their benefits and drawbacks; and 
         [0029]    In  FIG. 4 , there is shown a perspective view of a still further modified form of construction of the keyboard in accordance with the present invention in which a transparent tactile overlay  5  for the touch-sensitive screen  6  of a smart phone  14  provides four depressible transparent home keys for the fingers  7 , one depressible transparent home key for a thumb  11 , and depressions in the overlay for all non-depressible keys  4 . The transparent tactile overlay  5  prevents engagement of the touch-sensitive screen  6  where there are no depressions or depressible keys in the transparent tactile overlay  5  and prevents the accidental engagement of multiple keys at one time. The edges  13  of the transparent tactile overlay  5  are formed to bend around the edges of the smart phone  14  to keep the transparent tactile overlay  5  in position on the smart phone  14 . Many different approaches could be taken to achieve satisfactory results in the production of the tactile overlay  5 , including the following: Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch-sensitive screen  6  except where the non-depressible keys  4  are, and has holes where the dome shaped depressible home keys  7  and  11  are, and has thin sheet(s) of thermoformed flexible plastic that form the dome shaped depressible home keys  7  and  11 . Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch-sensitive screen  6  except where the non-depressible keys  4  are, with holes where the dome shaped depressible home keys  7  and  11  are, and with silicone dome depressible home keys  7  and  11 . Thermoformed flexible plastic like HDPE that creates an air gap between the plastic and the touch-sensitive screen  6  except where the keys are. Machined plastic thick enough to prevent engagement of the touch-sensitive screen  6 , with holes machined out for all keys, and with thin sheet(s) of thermoformed flexible plastic for dome shaped depressible home keys  7  and  11 . Machined plastic thick enough to prevent engagement of the touch-sensitive screen  6 , with holes machined out for all keys, and with silicone dome depressible home keys  7  and  11 . Injection-molded plastic thick enough to prevent engagement of the touch-sensitive screen  6  except where the keys are, with silicone dome depressible home keys  7  and  11 . Injection-molded plastic thick enough to prevent engagement of the touch-sensitive screen  6  except where the keys are, with holes left for all keys, and with a secondary thin sheet of thermoformed flexible plastic for dome shaped depressible home keys  7  and  11 . However, it cannot be said that there is one best method for achieving the overlay  5  as all of these approaches have their benefits and drawbacks; and 
         [0030]    In  FIG. 5 , there is shown a perspective view of an even still further modified form of construction of the keyboard in accordance with the present invention in which a tactile overlay  1  for a touch-sensitive keyboard  2  includes eight depressible home keys for the fingers  3  and depressions in the overlay  1  for all non-depressible keys  4 . The tactile overlay  1  prevents engagement of the touch-sensitive keyboard  2  where there are no depressions or depressible keys in the tactile overlay  1  and prevents the accidental engagement of multiple keys at one time. In this form of construction, the keyboard  2  has a convexly arced shape with the left and right halves of the keys spatially separated from one another to make room for a 3D sensor  15  built into the middle of the keyboard  2  that can track the motion of the fingers of a user in the space above said touch screen for the purpose of providing interactive control in mid-air of a computerized device. Many different approaches could be taken to achieve satisfactory results in the production of the tactile overlay  1 , including the following: Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch sensor except where the non-depressible keys  4  are, and has holes where the dome shaped depressible home keys  3  are, and has thin sheet(s) of thermoformed flexible plastic that form the dome shaped depressible home keys  3 . Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch sensor except where the non-depressible keys  4  are, with holes where the dome shaped depressible home keys  3  are, and with silicone dome depressible home keys  3 . Thermoformed flexible plastic like HDPE that creates an air gap between the plastic and the touch sensor except where the keys are. Machined plastic thick enough to prevent engagement of the touch sensor, with holes machined out for all keys, and with thin sheet(s) of thermoformed flexible plastic for dome shaped depressible home keys  3 . Machined plastic thick enough to prevent engagement of the touch sensor, with holes machined out for all keys, and with silicone dome depressible home keys  3 . Injection-molded plastic thick enough to prevent engagement of the touch sensor except where the keys are, with silicone dome depressible home keys  3 . Injection-molded plastic thick enough to prevent engagement of the touch sensor except where the keys are, with holes left for all keys, and with a secondary thin sheet of thermoformed flexible plastic for dome shaped depressible home keys  3 . However, it cannot be said that there is one best method for achieving the overlay  1  as all of these approaches have their benefits and drawbacks; and 
         [0031]    In  FIG. 6 , there is shown a perspective view of an even yet still further modified form of construction of the keyboard in accordance with the present invention in which an inflatable and deflatable tactile overlay  18  is permanently attached to a touch-sensitive screen  6 , providing eight depressible transparent home keys for the fingers  7 , two depressible transparent home keys for the thumbs  8 , and depressions in the tactile overlay  16  for all non-depressible keys  4 . The tactile overlay  18  prevents engagement of the touch-sensitive screen  6  where there are no depressions or depressible keys in the tactile overlay  16  and prevents the accidental engagement of multiple keys at one time. The raised surfaces of the tactile overlay  18  surrounding the depressions for all non-depressible keys  4  as well as the transparent home keys  7  and  8  can all be deflated to lay flat against the touch-sensitive screen  6  as shown in  FIG. 8 . For this form of construction of the keyboard, it would be best to use the inflatable and deflatable Tactile Layer technology created by Tactus Technology of Freemont, Calif.; and 
         [0032]    In  FIG. 7 , there is shown a perspective view of the form of construction of the keyboard shown in  FIG. 6  in which the inflatable and deflatable transparent tactile overlay  16  is shown deflated. The raised surfaces of the transparent tactile overlay  16  surrounding the depressions for all non-depressible keys  4  as well as the transparent home keys  7  and  8  are all shown deflated, laying flat against the touch-sensitive screen  6 ; and 
         [0033]    In  FIG. 8 , there is shown a perspective view of an even yet further still modified form of construction of the keyboard in accordance with the present invention in which a transparent tactile overlay  5  for a tablet computer  10  provides eight depressible transparent home keys for the fingers  7 , two depressible transparent home keys for the thumbs  8 , and depressions in the overlay  5  for all non-depressible keys  4 . The tactile overlay  5  prevents engagement of the touch-sensitive screen  6  of the tablet computer  10  where there are no depressions or depressible keys in the tactile overlay  5  and prevents the accidental engagement of multiple keys at one time. In this form of construction, the overlay  5  is built into a removable screen cover  17  for the tablet computer  10 , and in this perspective view the removable screen cover  17  is shown lifted off of the tablet computer  10 . Many different approaches could be taken to achieve satisfactory results in the production of the tactile overlay  5 , including the following: Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch-sensitive screen  6  except where the non-depressible keys  4  are, and has holes where the dome shaped depressible home keys  7  and  8  are, and has thin sheet(s) of thermoformed flexible plastic that form the dome shaped depressible home keys  7  and  8 . Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch-sensitive screen  6  except where the non-depressible keys  4  are, with holes where the dome shaped depressible home keys  7  and  8  are, and with silicone dome depressible home keys  7  and  8 . Thermoformed flexible plastic like HDPE that creates an air gap between the plastic and the touch-sensitive screen  6  except where the keys are. Machined plastic thick enough to prevent engagement of the touch-sensitive screen  6 , with holes machined out for all keys, and with thin sheet(s) of thermoformed flexible plastic for dome shaped depressible home keys  7  and  8 . Machined plastic thick enough to prevent engagement of the touch-sensitive screen  6 , with holes machined out for all keys, and with silicone dome depressible home keys  7  and  8 . Injection-molded plastic thick enough to prevent engagement of the touch-sensitive screen  6  except where the keys are, with silicone dome depressible home keys  7  and  8 . Injection-molded plastic thick enough to prevent engagement of the touch-sensitive screen  6  except where the keys are, with holes left for all keys, and with a secondary thin sheet of thermoformed flexible plastic for dome shaped depressible home keys  7  and  8 . However, it cannot be said that there is one best method for achieving the overlay  5  as all of these approaches have their benefits and drawbacks; and 
         [0034]    In  FIG. 9 , there is shown a perspective view of a still even yet further modified form of construction of the keyboard in accordance with the present invention in which a transparent tactile overlay  5  provides eight depressible transparent home keys for the fingers  7 , one depressible transparent home key for a thumb  8 , and depressions in the overlay  5  for all non-depressible keys  4 , including an elongated depression in the overlay  5  for a non-depressible touch-sensitive key for a thumb  18  that allows a thumb of the typist to move back and forth across its elongated depressed surface to scroll through and select alternate sets of data input commands that then appear on the touch-sensitive screen  6 . The transparent tactile overlay  5  is permanently affixed to a touch sensitive screen  6  built into the horizontal portion of a laptop computer  19 . The tactile overlay  5  prevents engagement of the touch-sensitive screen  6  where there are no depressions or depressible keys in the tactile overlay  5  and prevents the accidental engagement of multiple keys at one time. Variable sets of characters and commands can be chosen to appear on the horizontal touch-sensitive screen  6  so it can be used as a data input keyboard for various programs running on the laptop computer  19 . Many different approaches could be taken to achieve satisfactory results in the production of the tactile overlay  5 , including the following: Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch-sensitive screen  6  except where the non-depressible keys  4  and  18  are, and has holes where the dome shaped depressible home keys  7  and  8  are, and has thin sheet(s) of thermoformed flexible plastic that form the dome shaped depressible home keys  7  and  8 . Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch-sensitive screen  6  except where the non-depressible keys  4  and  18  are, with holes where the dome shaped depressible home keys  7  and  8  are, and with silicone dome depressible home keys  7  and  8 . Thermoformed flexible plastic like HDPE that creates an air gap between the plastic and the touch-sensitive screen  6  except where the keys are. Machined plastic thick enough to prevent engagement of the touch-sensitive screen  6 , with holes machined out for all keys, and with thin sheet(s) of thermoformed flexible plastic for dome shaped depressible home keys  7  and  8 . Machined plastic thick enough to prevent engagement of the touch-sensitive screen  6 , with holes machined out for all keys, and with silicone dome depressible home keys  7  and  8 . Injection-molded plastic thick enough to prevent engagement of the touch-sensitive screen  6  except where the keys are, with silicone dome depressible home keys  7  and  8 . Injection-molded plastic thick enough to prevent engagement of the touch-sensitive screen  6  except where the keys are, with holes left for all keys, and with a secondary thin sheet of thermoformed flexible plastic for dome shaped depressible home keys  7  and  8 . However, it cannot be said that there is one best method for achieving the overlay  5  as all of these approaches have their benefits and drawbacks; and 
         [0035]    In  FIG. 10 , there is shown a perspective view of a yet even still further modified form of construction of the keyboard in accordance with the present invention in which a tactile overlay  1  for a touch-sensitive keyboard  2  provides eight depressible home keys for the fingers  3 , one depressible elongated dome home key for the thumbs  20 , and depressions in the overlay for all non-depressible keys  4 . The tactile overlay  1  prevents engagement of the touch-sensitive keyboard  2  where there are no depressions or depressible keys in the tactile overlay  1  and prevents the accidental engagement of multiple keys at one time. In this form of construction, the left and right halves of the keys are set at an oblique angle relative to one another and are separated to make room for an elevated touch-sensitive platform  21 . Many different approaches could be taken to achieve satisfactory results in the production of the tactile overlay  1 , including the following: Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch sensor except where the non-depressible keys  4  are, and has holes where the dome shaped depressible home keys  3  and  20  are, and has thin sheet(s) of thermoformed flexible plastic that form the dome shaped depressible home keys  3  and  20 . Thermoformed semi-rigid plastic or injection molded plastic that creates an air gap between the plastic and the touch sensor except where the non-depressible keys  4  are, with holes where the dome shaped depressible home keys  3  and  20  are, and with silicone dome depressible home keys  3  and  20 . Thermoformed flexible plastic like HDPE that creates an air gap between the plastic and the touch sensor except where the keys are. Machined plastic thick enough to prevent engagement of the touch sensor, with holes machined out for all keys, and with thin sheet(s) of thermoformed flexible plastic for dome shaped depressible home keys  3  and  20 . Machined plastic thick enough to prevent engagement of the touch sensor, with holes machined out for all keys, and with silicone dome depressible home keys  3  and  20 . Injection-molded plastic thick enough to prevent engagement of the touch sensor except where the keys are, with silicone dome depressible home keys  3  and  20 . Injection-molded plastic thick enough to prevent engagement of the touch sensor except where the keys are, with holes left for all keys, and with a secondary thin sheet of thermoformed flexible plastic for dome shaped depressible home keys  3  and  20 . However, it cannot be said that there is one best method for achieving the overlay  1  as all of these approaches have their benefits and drawbacks.