JP2845290B2 - Coordinate input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device for inputting cursor position coordinate data in a display device used for a personal computer or the like.

[0002]

2. Description of the Related Art One type of coordinate input device such as cursor position coordinate data on a display device is provided with a sphere, and the position of the cursor on a display screen is changed by the rotation of the sphere. Can be changed arbitrarily.

FIG. 4 is a schematic diagram of such a coordinate input device, wherein 1 is a sphere, 2 is a housing, 3X and 3Y are driven rollers, 4X and 4Y are rotating shafts, 5X and 5Y are choppers,
6X and 6Y are photo interrupters, and 7X and 7Y are conductors.

In FIG. 1, a sphere 1 is provided in a housing 2 so that a part of the sphere 1 is outside the housing 2 and is rotatable with respect to a center point thereof. Followed rollers 3X, 3Y fixed to rotating shafts 4X, 4Y are pressed against the surfaces of two radial spheres 1 different by 90 °. These rotating shafts 4X,
Fixed to the ends of the 4Y are slits 5X and 5Y in which slits of the same size are provided at equal intervals over the entire outer peripheral portion, and an LED is provided for each of the slits 5X and 5Y.
Photo interrupters 6X and 6Y each including a light emitting element such as a photo transistor and a light receiving element such as a photo transistor. These light-emitting elements emit light when a driving voltage is applied thereto via the conductive wires 7X and 7Y, and the light-emitting elements 5X and 5Y emit light.
As the Y rotates, the conductor 7
A pulse is obtained via X and 7Y.

By operating a portion of the sphere 1 that has come out of the housing 2 with a fingertip or the like, the sphere 1 rotates about its center point. Now, assuming that the sphere 1 is rotated in the direction of the arrow X, the driven roller 3X rotates in a direction corresponding to the rotation direction, and the chopper 5X also rotates in that direction, and the light receiving element of the photointerrupter 6X generates a pulse. When the sphere 1 is rotated in the direction of the arrow Y, the driven roller 3Y rotates in a direction corresponding to the rotation direction, and
Rotates in that direction, and the light receiving element of the photointerrupter 6Y generates a pulse. Of course, if the sphere 1 is rotated in a direction different from the directions of the arrows X and Y, the choppers 5X and 5Y rotate, and the light receiving elements of the photointerrupters 6X and 6Y generate pulses.

The photo-interrupters 6X, 6Y are positioned with respect to the nippers 5X, 5Y such that the outer peripheral portion provided with the slits of the nippers 5X, 5Y is located between the light-emitting element and the light-receiving element. . The light emitting element emits light at all times and the light is received by the light receiving element. However, when the tips 5X and 5Y rotate, the light from the light emitting element is chopped by the slits and the light shielding portion between the slits. You. Thus, a pulse is obtained each time the slit passes from the light receiving element.

The number of pulses corresponding to the amount of rotation of the sphere 1 is obtained from these light receiving elements. Therefore, the pulses from the photointerrupters 6X and 6Y are counted, and the cursor is moved on the display screen of the display device by a distance corresponding to these count values. Can be changed.

Here, if the rotation of the sphere 1 in the directions of the arrows X and Y is forward rotation, and the rotation of the sphere 1 in the opposite direction is reverse rotation, the cursor on the screen shown in the figure is moved right and left according to the forward and reverse rotation of the sphere 1 , Can be moved up and down. For this purpose, means for detecting the forward and reverse directions of the sphere 1 are provided. This will be described below.

Each of the photointerrupters 6X and 6Y shown in FIG. 4 is provided with two pairs of light-emitting elements and light-receiving elements opposed thereto (hereinafter referred to as photodetectors). FIG. 5 shows the arrangement of the light emitting elements in these two photodetectors.
5Y, 8A and 8B are these light-emitting elements, and 10 is a chopper 5
It is a slit.

In FIG. 5, if n slits 10 are provided on the outer periphery of the chopper 5, the slit pitch θ is 360 ° ÷ n. Light emitting element 8A, 8B
Is an odd multiple of 1/4 of this slit pitch θ, that is,
Assuming that m is an integer of 1 or more, they are arranged at a distance d corresponding to (2m-1) θ / 4.

[0011] Therefore, now, as shown, (at this time, m = 2) the distance d is Suritsutopitsuchi 3q / 4 corresponds to the output pulse A-phase pulse P _A of the light receiving element (not shown) facing the light emitting element 8A when the output pulse of the light receiving element (not shown) facing the light emitting element 8B and B-phase pulse P _B, when rotating in the direction of arrow R from the state Chiyotsupa 5 is shown, as shown in FIG. 6, a-phase pulse P _a B phase pulse P _B is が cycle of these pulses (90
°) proceeds, when rotating in the opposite direction to the arrow R from Chiyotsupa 5 is illustrated state, as shown in FIG. 7, 1/4 period of the B-phase pulse P _B is these pulses to the A-phase pulse P _A (90 °) late. Thus, the phase relationship between the A-phase pulse P _A and B phase pulse P _B is reversed with ± 90 ° depending on the direction of rotation of the Chiyotsupa 5. Therefore, by detecting this phase relationship, it is possible to determine the rotation direction of the chopper 5, that is, the forward or reverse rotation of the sphere 1 (FIG. 4).

FIG. 8 is a block diagram showing one conventional means for forming the position coordinate data of the cursor by processing the A and B phase pulses, and 6 is a photointerrupter 6 of FIG.
X or 6Y, 8A and 8B are light emitting elements, 9A and 9B are light receiving elements, 11 is an up-down counter, 12 is a rotation direction detecting circuit, and 13 is a control unit.

In FIG. 1, light emitting elements 8A and 8B are shown in FIG.
And the light receiving elements 9A and 9B are opposed to the light emitting elements 8A and 8B, respectively. The outer periphery where the slits are arranged is composed of the light emitting elements 8A and 8B and the light receiving element 9.
A and 9B, and the rotation of the chopper obtains an A-phase pulse P _A and a B-phase pulse P _B having the phase relationship shown in FIGS. 6 and 7 from the light receiving elements 9A and 9B.

The up-down counter 11 outputs an A-phase pulse P
Each edge of the _A and B phase pulses P _B is counted, and the count value N is supplied to the control unit 13. A-phase pulse P
_{The A} and B phase pulses P _B are supplied to the rotation direction detection circuit 12,
The direction of rotation of the chopper at each edge of the pulses P _A and P _B is detected. As shown in FIGS. 6 and 7, the A-phase pulse P _A
Different from ± 90 ° in accordance with the rotational direction of the phase relationship between the B-phase pulse P _B is Chiyotsupa for the level of B-phase pulse P _B at edges of the A-phase pulse P _A, A at the edge of the B-phase pulse P _B By determining the level of the phase pulse P _A, the level of the output signal V _R of the rotation direction detection circuit 12 differs depending on the rotation direction of the chopper, and indicates the rotation direction. The output signal V of the rotation direction detection circuit 12
_{By R} , the counting direction of the up-down counter 11 is changed. The control unit 13 processes the count value N from the counter 11, is moved by a distance corresponding to the direction to the count value N corresponding cursor on the level of the signal V _R on the display screen. As described above, by rotating the sphere 1 (FIG. 4) with a fingertip, the cursor can be moved in an arbitrary direction on the display screen by an arbitrary distance.

[0015]

In order to mount the coordinate input device on a keyboard, it is necessary to reduce the size of the coordinate input device. Photointerrupters also need to be small. In order to reduce the size of the photointerrupter, the distance between the photodetectors provided therein and the slit pitch θ (2 m-
1) It is necessary to keep the value corresponding to / 4 and to make it as small as possible, that is, to arrange the two photodetectors in the photointerrupter as close as possible.

However, when the two photodetectors are brought closer to each other, the following problem occurs. That is,
In order to reduce the size of the photointerrupter, as shown in FIG. 9, recesses 14 and 15 are provided in the respective projecting portions of the U-shaped photointerrupter 6 and two recesses 14 are provided in one recess 14.
The two light emitting elements 8A and 8B are molded and fixed with a transparent molding member 16, and the light emitting elements 8A and 8B are
A, 8B, two light receiving elements 9A, 9
B is molded and fixed by a transparent mold member 17, and when the light emitting elements 8A and 8B and the light receiving elements 9A and 9B are arranged close to each other, as shown in FIG.
A receives the light LA1 from the light emitting element 8A opposed thereto, but also receives a part of the light LB2 from the light emitting element 8B, and the light receiving element 9B also receives light from the light emitting element 8B opposed thereto. Not only the light LB1 but also some light LA2 from the light emitting element 8A is received. If light receiving from the light emitting elements 8B, 8A where the light receiving elements 9A, 9B do not face each other is referred to as light interference, the light interference causes the chopper 5 to chop light from the light emitting elements 8A, 8B. However, the phase relationship between the pulses P _A and P _B from the light receiving elements 9A and 9B may deviate from the above ± 90 °, and an error may occur in the detection of the rotation direction of the chopper.

An object of the present invention is to provide a coordinate input device which solves such a problem, reduces the size of the photointerrupter, and can prevent malfunction.

[0018]

In order to achieve the above object, the present invention provides a method in which first and second light emitting elements of the same interrupter emit light alternately, and the first light emitting element emits light when the first light emitting element emits light. A first means for latching the output of the first light receiving element facing the first light emitting element; and a second means for latching the output of the second light receiving element opposed to the second light emitting element when the second light emitting element emits light. .

[0019]

When the first light receiving element receives the light from the second light emitting element, and the second light receiving element receives the light from the first light emitting element, the first means emits the first light. The output of the first light receiving element when the element emits light is latched, and the second means latches the output of the second light receiving element when the second light emitting element emits light. The output level depends on whether the first light receiving element has received the light from the first light emitting element, and the output level of the second means is that the second light receiving element has the second light receiving element. This depends on whether or not light from the element has been received. Thus, light interference is eliminated.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an essential part of an embodiment of a coordinate input device according to the present invention. Reference numerals 18A and 18B denote latch circuits, and portions corresponding to those in FIG.

In FIG. 1, one light emitting element 8A is driven by a pulse voltage _VA as shown in FIG. 2 to emit light intermittently, and the other light emitting element 8
B also intermittently emits light when by connexion driving the pulse voltage V _B having a phase different from the pulse voltage V _A shown in FIG. That is, the light emitting elements 8A and 8B emit light alternately, and their light emitting periods do not overlap. These pulse voltages V _A , V _B
Is set sufficiently higher than the chopping frequency by a chopping machine (not shown).

Therefore, when the light receiving elements 9A and 9B are shielded from light by the chopper, their outputs are zero.
When light passes through the slit of the chopper, the light receiving element 9
A and 9B output pulse trains P _A ′ and P _B ′ that match the light emission timing of the light emitting elements 8A and 8B. In this case, the light emitting elements 8A and 8B are arranged close to each other, and the light receiving element 9A is arranged to face the light emitting element 8A, and the light receiving element 9B is arranged to face the light emitting element 8B. Taking the case of rotating to R as an example, as described in FIG. 10, the light receiving element 9A also receives light from the light emitting element 8B, and the light receiving element 9B also receives light from the light emitting element 8A. Therefore, the output pulse train P _A ′ of the light receiving element 9A is provided.
As shown in FIG. 3, a pulse generated by receiving light from the light emitting element 8A shown by a solid line and a light emitting element 8 shown by a broken line
It is composed of a pulse due to the reception of light from B, and even if the light from the light emitting element is blocked by the chopper and the pulse shown by the solid line disappears, there is a pulse shown by the broken line for a while. Output pulse train P _B 'of light receiving element 9B
Similarly, as shown in FIG. 3, it is composed of a pulse obtained by receiving light from the light emitting element 8B shown by a solid line and a pulse generated by receiving light from the light emitting element 8A shown by a broken line, and shown by a broken line. The pulse is output from the light receiving element 9B prior to the pulse indicated by the solid line. For this reason, the period of only the pulse indicated by the broken line of the pulse train P _A ′ and the period of the pulse indicated by the broken line of the pulse train P _B ′ may partially overlap.

In FIG. 1, the output pulse P _A ′ of the light receiving element 9A is supplied to a latch circuit 18A, and the control unit 1
It is latched by Ratsuchiparusu phi _A from 3. The output pulse train P _B ′ of the light receiving element 9B is
Is supplied to the B, it is latched by Ratsuchiparusu phi _B from the control unit 13. Here, as shown in FIG. 2, the latch pulse φ _A is within the pulse period of the pulse voltage _VA driving the light emitting element 8A, and the latch pulse φ _B is within the pulse period of the pulse voltage V _B driving the light emitting element 8B. It is in. Therefore, since the latch pulse φ _A has the same timing as the pulse indicated by the solid line in the output pulse train P _A ′ of the light receiving element 9A shown in FIG. 3, the latch circuit 18A performs the pulse indicated by the solid line in the pulse train P _A ′. Only to be latched,
Was but connexion, from the latch circuit 18A, as shown in FIG. 3, pulse representing a period of the pulse indicated by this solid line is present is output as the A-phase pulse P _A. Similarly, because Ratsuchiparusu phi _B is the timing pulse shown by the solid line of the output pulse train P _B 'of the light receiving element 9B shown in FIG. 3 match, latch circuit 18B is able to latch only the pulses shown in this solid becomes, the but connexion, from the latch circuit 18B, as shown in FIG. 3, pulse representing a period of the pulse indicated by this solid line is present is output as a B-phase pulse P _B.

[0024] In this way, the latch circuit 18A is output A-phase pulse P _A by that receives light from the light-receiving element 9A is emitting device 8A, from the latch circuit 18B from the light receiving element 9B is emitting element 8B the B-phase pulse P _B by that receive light will be is output, the light receiving elements 9A is receiving light from the light emitting element 8B, the light receiving element 9B
Even if there is light interference that receives light from the light emitting element 8A,
An A-phase pulse P _A and a B-phase pulse P _{B which} are not affected by this are obtained. When the rotation direction of the chopper is opposite to the above, the A-phase pulse P _A and the B-phase pulse P _B
Is opposite to that shown in FIG. 3 as described with reference to FIGS.

[0025] was but connexion, the light emitting device 8A and 8B, be located close to the position of each optical interfering light receiving elements 9A and 9B is produced by the A-phase pulse P _A and B phase pulse P _B, the direction of rotation exactly signal V _R is obtained which represents the direction of Chiyotsupa from the detection circuit 12, it is possible to miniaturize the photo-interrupter 6.

The power consumption of the light emitting elements 8A and 8B is reduced as compared with the case where the generating elements 8A and 8B emit light continuously.

[0027]

As described above, according to the present invention,
The effect of light interference at the photointerrupter can be eliminated, so that the photointerrupter can be reduced in size and the rotational direction of the sphere can be determined with certainty.
It is possible to provide a low power consumption coordinate input device that is significantly reduced in size and does not malfunction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a coordinate input device according to the present invention.

FIG. 2 is a timing chart showing a light emission timing of a light emitting element and a latch timing of a latch circuit in FIG. 1;

FIG. 3 is a diagram showing input / output signals of the latch circuit in FIG. 1;

FIG. 4 is a diagram schematically illustrating an overall configuration of a mechanism unit of the coordinate input device.

5 is a diagram showing an arrangement relationship of two photodetectors of the photointerrupter of FIG. 4 with respect to a chopper.

FIG. 6 is a diagram showing a phase relationship between output pulses of two photodetectors when the chopper rotates in the direction of arrow R in FIG. 5;

FIG. 7 is a diagram showing the phase relationship between output pulses of two photodetectors when the chopper rotates in the direction opposite to the arrow R in FIG.

FIG. 8 is a block diagram showing an example of a conventional coordinate input device.

FIG. 9 is a perspective view showing an example of a photointerrupter used in a coordinate input device.

FIG. 10 is a diagram illustrating light interference in the photointerrupter illustrated in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sphere 5,5X, 5Y Jitter 6,6X, 6Y Photo interrupter 8A, 8B Light emitting element 9A, 9B Light receiving element 10 Slit 11 Counter 12 Rotation direction detecting circuit 18A, 18B Latch circuit

Claims (1)

(57) [Claims] 1. A first light-emitting element, a first light-receiving element facing the first light-emitting element, and a second light-receiving element facing the second light-emitting element are mounted on the same support. A photo-interrupter, and a chopper rotating with the rotation of the sphere chops the light from the first and second light-emitting elements, so that the pulses having different phases from the first and second light-receiving elements. A first means for alternately emitting light from the first and second light emitting elements, and an output level of the first light receiving element at a timing at which the first light emitting element emits light. And a third means for detecting the output level of the second light-receiving element at a timing at which the second light-emitting element emits light,
A coordinate input apparatus characterized in that pulses having different phases can be obtained from the second and third means.