Coordinates input device

• US 5,518,078 A
• Filed: 11/06/1992
• Issued: 05/21/1996
• Est. Priority Date: 11/08/1991
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Shiraishi, Naoki, Hashimoto, Katsuhiko, Tsujioka, Hiroshi
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): Kim, Kevin
• Application Number:
  US07/972,908
• Time in Patent Office: 1,292 Days
• Field of Search: 178/18, 178/19, 178/20, 345/173, 345/174, 348/709.11, 382/13
• US Class Current: 178/18.05
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

In a panel member of a coordinates input device, a first input unit and a second input unit are set on a pair of transparent electrodes and the first input unit only allows input by a member of a relatively large pressing pressure such as by using a pen. The second input unit also allows input by pressing with a member of a relatively small pressing pressure, such as a finger, and thus is not limited to a pen. In order to achieve a coordinates input device of enhanced accuracy in the reading of pressing position by accurately measuring the pressing level at the pressing position, the device possesses a structure in which an X-direction resistive film and a Y-direction resistive film are separated by a tiny clearance and, when the pressing position is pressed, various switches are controlled by a specified procedure such that the X-direction and Y-direction levels of the contact resistance due to the pressing of the position are detected and, only when the pressing levels are sufficient, are coordinates of the pressing position measured.

Claims

1. A coordinates input device comprising:

a first input unit, at a lower portion a panel member, having a transparent resistance layer formed on the entire inner surface of predetermined first regions of each of a pair of opposed electric insulating transparent substrates, and an electrode formed at each of two opposite ends of each transparent resistance layer such that each pair of electrodes extend in mutually crossing directions; and

a second input unit, at an upper portion of said panel member, forming plural band-shaped transparent electrodes extending in mutually crossing directions, in second regions different from the first regions of the transparent substrates;

means to discriminate between input from the first input unit versus input from the second input unit without disabling input from either unit;

wherein bumps are disposed at predetermined intervals at least on one transparent substrate inner surface of the first input unit, and bumps are disposed on at least one transparent substrate inner surface of the second input unit at intervals greater than the intervals in the first input unit.

2. A coordinates input device as claimed in claim 1 wherein:

the bumps are formed approximately in a truncated cone, and the peripheral edge of the upper end contacting with the transparent resistance layer or transparent electrode formed on the confronting substrate is rounded.

3. A coordinates input device as claimed in claim 1 wherein:

the bumps are formed approximately in a truncated pyramid, and the peripheral edge of the upper end contacting with the transparent resistance layer or transparent electrode formed on the confronting substrate is formed rounded.

4. A coordinates input device as claimed in claim 1 wherein:

the height of the bumps in the first input unit is selected larger than the height of the bumps in the second input unit.

5. A coordinates input device comprising:

an input panel having a transparent resistance layer formed on mutually confronting inner surfaces of a pair of electric insulating transparent substrates, and an electrode formed at each of two opposite ends of each transparent resistive layer such that each pair of electrodes extend in mutually crossing directions,

first means for converting an analog signal from the electrodes into a digital signal according to a first input threshold signal or a second input threshold signal which is different from said input signal, and

threshold selecting means for selecting either the first input threshold signal or the second input threshold signal as the active threshold value in said means for converting an analog signal, said threshold selecting means including;

a control device for supplying signals of high level or low level to first and second signal lines, respectively, when said first input threshold is to be set, and for supplying signals of low level and high level to said first and second signal lines, respectively, when said second input threshold is to be set;

said first signal line connected to the base of a first transistor and said second signal line connected to the base of a second transistor, said first transistor connected between a common first supply voltage and a first resistor, and said second transistor connected between a common supply voltage and a second resistor;

said first resistor having a resistance lower than that of said second resistor, both said first and said second resistors connected to one end of a third resistor, which third resistor is connected at its other end to a common second supply voltage different than said first supply voltage;

an output of said threshold selecting means being connected to a node connecting said first resistor, said second resistor, and said third resistor.

6. A coordinates input device as claimed in claim 5 wherein said first and second input thresholds are set on the basis of the pressing force per unit area required to activate the input panel, and a first activation state of relatively large pressing pressure and a second activation state of relatively small pressing pressure are set.

7. A coordinates input device as claimed in claim 6 wherein:

the level of the threshold signal in the first activation state is selected higher than the level of the threshold signal in the second activation state.

8. A coordinates input device comprising a conductive first sheet member to which a voltage is applied so as to form a voltage gradient in a first direction therein, and a conductive second sheet member to which a voltage is applied so as to form a voltage gradient in a second direction orthogonal to the first direction therein, and disposed so that said sheet members confront each other across a uniform specific interval such that the sheet members may contact each other at a pressed position and wherein the pressed position is read by a combination of electric signals and further including:

first means for applying said voltage so as to form a voltage gradient in the first direction, and for detecting the pressing level in the first sheet member as an electric signal,

second means for applying said voltage so as to form a voltage gradient in the second direction, and for detecting the pressing level in the second sheet member as an electric signal,

first reading means for reading the pressed position as an electric signal level of a voltage gradient in the first direction, responsive to the detection signal in the first means, and,

second reading means for reading the pressed position as an electric signal of a voltage gradient in the second direction, responsive to the detection signal level of the second means.

9. A coordinates input device as claimed in claim 8 wherein:

a voltage is applied to either said first or said second conductive sheet members, wherein the pressing level is detected and the pressing position is read, and wherein a voltage is then applied to the other conductive sheet member, the pressing level is detected and the pressing position is read.

10. A method of measurement of coordinates using a coordinate input device, said method comprising the following steps performed in the order listed:

(a) applying voltage to one side of a conductive first sheet member of a coordinate input device for measurement of the X-direction pressing level;

(b) measuring the X-direction pressing level and, if sufficient, proceeding with step (c);

if not sufficient, ending the measurement;

(c) applying voltage to the side opposite said one side of a conductive first sheet member of said coordinate input device for measurement of the X-direction coordinate;

(d) measuring the X-direction coordinate;

(e) applying voltage to one side of a conductive second sheet member of said coordinate input device for measurement of the Y-direction pressing level;

(f) measurement of the Y-direction pressing level and, if sufficient, proceeding with step (g);

if not sufficient, ending the measurement;

(g) applying voltage to one side, while grounding the opposite side of a conductive second sheet member of said coordinate input device for measurement of the Y-direction coordinate;

(h) measuring of the Y-direction coordinate.