FIG. 4A is a block diagram of a switch circuit of the 18. In this regard, the keyboard housing 20 includes a
circuit of FIG. 4; left hand portion 22 and a right hand portion 24 that are
FIG. 5 is a pictorial view of another membrane key- mounted hingeably together through a living hinge,
board constructed in accordance with the present in- shown generally at 26. For the purpose of permitting
vention and illustrated forming a part of a foldable com- 5 the system 10 to be folded into a substantially flat pack
puter having a liquid crystal display panel; age for storage or transportation purposes, the right
FIG. 6 is an enlarged face view of a group of repre- portion 24 of the housing unit 20 is mounted hingeably
sentative keys of the keyboard of FIG. 5; to the liquid crystal panel 12 by a living hinge 27. An
FIG. 7 is a sectional view of the keys of FIG. 6 taken other living hinge 28 integrally connects a triangularly
substantially on line 7—7 thereof, illustrating an en- 10 shaped support flap 17 for helping to support the panel
larged circled portion; 12 in an upright position as shown in FIG. 1.
FIG. 8 is a block diagram of an electronic circuit The keyboard housing 20 is composed of a suitable
arrangement for the keyboard of FIG. 5; and thermoplastic material that may be folded repeatedly
FIG. 9 is a sectional view of the keys of FIG. 2 taken about the living hinges In this regard, it should be noted
substantially on line 9—9 thereof. 15 that when the left portion 22 of the keyboard housing 20
BEST MODE FDRCAHHNO OUT THE TM3 ^£ftEt*S5S£
IN VfcN I ION the right ^ left portion 22 and 24 become disposed at
Referring now to the drawings and more particularly an angle 8 of between about 25° and about 36° relative to FIG. 1 thereof, there is shown a membrane keyboard 20 to one another. A more preferred angle B is between system 10 which is constructed in accordance with the about 30° and about 33°, and a most preferred angle of present invention. The system generally comprises a 6 is about 31°.
liquid crystal display panel 12 for visually displaying The configuration of character keys in the left side 22 character information, a microprocessor 14 (FIG. 4) for and the right side 24 of the keyboard 16 is more fully processing information and a membrane keyboard 16 25 described in the above mentioned copending U.S. pafor permitting a user to enter information into the mi- tent application.
croprocessor 14 for processing and display purposes. The membrane keyboard 16 also includes a left side The display panel 12, microprocessor 14 and membrane keypad arrangement and right side keypad arrangement keyboard 16 are mounted in a substantially flat foldable shown generally at 30 and 31 respectively. As the consystem housing unit 18. In this regard, the housing unit 30 struction of the keypad arrangements 30 and 31 are 18 is foldable into a thin, flat generally rectangularly substantially similar to one another, only the leftside shaped compact unit that may be conveniently carried keypad arrangement 30 will be described in greater by a user. detail.
In operation, the system 10 permits a user to enter Considering now the keypad arrangement 30 in data quickly and accurately into the microprocessor 14 35 greater detail with reference to FIGS. 1-4, the left for processing purposes. In this regard, a skilled touch keypad arrangement 30 generally comprises a keypad typist is able to use the membrane keyboard 16 for en- printed circuit board 32 (FIG. 3) and a control circuit tering data at substantially the same speed and with 70 (FIG. 4) for generating electrical signals to produce substantially the same accuracy according to familiar sensory responses and codes when the individual chartouch typing techniques. 40 acter keys are depressed. Arrangement 30 also includes
To use the system 10, a user unfolds the housing unit a membrane panel 33 having a generally rectangular 18 into its operating configuration as best seer in FIG. 1. group of membrane character keys, such as keys 34-39 In this regard, when the housing unit 18 is unfolded, the shown in FIG. 2. The membrane keys, such as keys system 10 is immediately powered by the portable 34-39, are configured or arranged in a series of parallel power source causing the microprocessor 14 to produce 45 spaced apart, staggered rows, such as rows 40, 41, 43, a reference character such as a cursor on the display 45, and 47, and columns, such as 42, 44, and 46 to facilipanel 12. The user then begins entering information into tate touch typing techniques by an operator, the microprocessor 14 via the membrane keyboard 16 in As best seen in FIGS. 1 and 2, selected ones of the substantially the same manner as a touch typist would character keys have a character indicia dispersed do according to familiar touch typing techniques. 50 thereon, such as the character indicia 34D, 35F, 36G,
As best seen in FIG. 1, the interconnected membrane 37E, 38R, and 39T on keys 34 -39 respectively. The keys are arranged in rows and columns, where'the indi- character indicia on each of the selected keys, such as vidual rows of character keys have different transverse indicia 37E is disposed at an angle 6/2 relative to the height to facilitate the rapid and efficient entry of char- transverse dimension of the group 30. acter information. Also, as will be explained hereinafter 55 Considering now the panel 33 in greater detail with in greater detail, sensory responses are produced as the reference to FIGS. 2-3, the panel 33 generally cornuser enters information in order to further facilitate the prises a pair of inner and outer thin sheets of thermorapid and efficient entry of information. In this regard, plastic material bonded together by any suitable means, when a user presses any one of the character keys, the such as heat welding. In this regard, the panel 33 inuser will sense a tactile response in the form of a gentle 60 eludes an outer keypad sheet 51 for forming the individreaction force, indicating that the selected key has been ual character keypads, such as pads 34-39, and an inner successfully actuated. In addition, the user will also sheet 61 for establishing a communication path between hear a audible sound indicative of the selected key hav- the individual character keys, such is keys 34-39, and a ing been successfully actuated. plurality of keypad control circuits, such as the keypad
Considering now the membrane keyboard 16 in 65 control circuits 31A, 31B, and 31C as shown in FIG. 1. greater detail with reference to FIGS. 1-4, the key- For the purpose of forming the individual character board 16 generally comprises a keyboard housing 20 keypads, the keypad sheet 51 is molded into the characwhich forms an integral part of the system housing unit ter keys, each having finger engageable recessed key