Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
153 words
Apparatus for position determination in a data space, the apparatus comprising a generally flat tablet (20) formed of a solid acoustically-conductive material; a movable element (30) adapted to be manually movable over the tablet surface, the element having a tapered tip (31) which contacts the surface of the tablet, and an acoustic transducer. (33) coupled to the tip (31); fixed acoustic transducer means (21,22) coupled to the tablet (20); means for energizing acoustic energy to propagate in either direction between the transducer (33) of the movable element (30)and the fixed transducer means (21,22), the midrange frequency of the energy being selected such that the wave length of the energy mode propagating parallel to the tablet surface is a function of the tablet thickness; and means for determining the time of propagation of the acoustic energy travelling, in either direction,between the transducer (33) of the movable element (30) and the fixed transducer means (20,21).
Claim 2
Dependent Claim
153 words
Apparatus for position determination in a data space, the apparatus comprising a generally flat tablet (20) formed of a solid acoustically-conductive material; a movable element (30) adapted to be manually movable over the tablet surface, the element having a tapered tip (31) which contacts the surface of the tablet, and an acoustic transducer. (33) coupled to the tip (31); fixed acoustic transducer means (21,22) coupled to the tablet (20); means for energizing acoustic energy to propagate in either direction between the transducer (33) of the movable element (30)and the fixed transducer means (21,22), the midrange frequency of the energy being selected such that the wave length of the energy mode propagating parallel to the tablet surface is a function of the tablet thickness; and means for determining the time of propagation of the acoustic energy travelling, in either direction,between the transducer (33) of the movable element (30) and the fixed transducer means (20,21).
Claim 3
Dependent Claim
159 words
Apparatus for obtaining position and writing pressure information in a data space, the apparatus comprising a generally flat tablet (20) formed of a solid acoustically-conductive material; a movable element (30) adapted to be manually movable over the tablet surface, the element including a piezoelectric transducer (33) coupled to a tapered tip (31) which contacts the surface of the tablet; fixed acoustic transducer means (21,22) coupled to the tablet (20); means for energising acoustic energy to propagate in either direction between the transducer (33) of the element (30) and the fixed transducer means (21,22); means for determining the time of propagation of the acoustic energy travelling, in either direction, between the transducer (33) of the element (20) and the fixed transducer means (21,22); and means for determining the amplitude of the acoustic energy which has propagated through the tablet (20), the pressure of the element tip (31) on the tablet (20) being determined as a function of the determined amplitude.
Claim 4
Dependent Claim
159 words
Apparatus for obtaining position and writing pressure information in a data space, the apparatus comprising a generally flat tablet (20) formed of a solid acoustically-conductive material; a movable element (30) adapted to be manually movable over the tablet surface, the element including a piezoelectric transducer (33) coupled to a tapered tip (31) which contacts the surface of the tablet; fixed acoustic transducer means (21,22) coupled to the tablet (20); means for energising acoustic energy to propagate in either direction between the transducer (33) of the element (30) and the fixed transducer means (21,22); means for determining the time of propagation of the acoustic energy travelling, in either direction, between the transducer (33) of the element (20) and the fixed transducer means (21,22); and means for determining the amplitude of the acoustic energy which has propagated through the tablet (20), the pressure of the element tip (31) on the tablet (20) being determined as a function of the determined amplitude.
Claim 5
Dependent Claim
37 words
Apparatus according to claim 1 or claim 2, further comprising means (125,71,72) for adjusting the amplitude of the acoustic energy as a function of the time of travel of the acoustic wave energy in the tablet (20).
Claim 6
Dependent Claim
46 words
Apparatus according to any of the preceding claims, wherein the energy mode propagating parallel to the tablet surface is compressional mode energy, and the frequency is selected such that the wavelength of the compressional mode energy is about four times the thickness of the tablet (20).
Claim 7
Dependent Claim
48 words
Apparatus according to any of claims 1 to 3, wherein the energy mode propagating parallel to the tablet surface is shear mode energy, and the frequency is selected such that the wavelength of the shear mode energy is about the same as the thickness of the tablet (20).
Claim 8
Dependent Claim
16 words
Apparatus according to any of the preceding claims, wherein the tablet (20) is formed of plastic.
Claim 9
Dependent Claim
20 words
Apparatus according to any of the preceding claims, wherein the fixed transducer means (20,21) are formed of a piezoelectric plastic.
Claim 10
Dependent Claim
24 words
Apparatus according to claim 7, wherein the fixed transducer means (20,21) comprise strips of piezoelectric plastic disposed on adjacent edges of the tablet (20).
Claim 11
Dependent Claim
25 words
Apparatus according to any of the preceding claims, wherein the movable element (30) is a stylus, and the tip (31) of the stylus is horn-shaped.
Claim 12
Dependent Claim
53 words
Apparatus according to any of the preceding claims,wherein the transducer (33) in the movable element (30) comprises a disc of piezoelectric material, and wherein the tip (31) is formed of a material whose acoustic impedance is between the acoustic impedance of the disc':of piezoelectric material and the acoustic impedance of the tablet material.
Claim 13
Dependent Claim
32 words
Apparatus according to any of the preceding claims, wherein the tip (31) of the movable element (30) includes a resilient contact (31A) which can slide along the surface of the tablet (20)..
Claim 14
Dependent Claim
15 words
Apparatus according to any of the preceding claims, wherein the acoustic energy is ultrasound energy.