JPH0624906Y2 - Optical touch screen device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an optical touch screen device for touching a display screen of a display device such as a CRT with a finger or the like and inputting information displayed at the position, More specifically, the present invention relates to an optical touch screen device that detects a position on the screen designated by a finger by blocking a light beam that crosses the screen with a finger.

<Prior Art> Optical touch screen devices have recently been used as various man-machine interface devices because data can be input by a simple method such as specifying the position of specific display information displayed on the screen with a finger. Has been done.

FIG. 3 is a conceptual diagram of the configuration of this type of optical touch screen device. In the figure, 1 is a display screen (screen) such as a CRT, 21 to 2n are light emitting elements arranged on one of two sides of the display screen 1 facing each other, 31 to 3n are light receiving elements arranged on the other side, 4 Is a plurality of light emitting elements 21 to
A light source drive circuit 5 for sequentially emitting 2n inputs signals from a plurality of light receiving elements, and sequentially receives signals from the light receiving elements at the timing when the light emitting elements facing each other emit light, and the light beam from the light emitting elements is blocked. It is a position detection circuit that detects the position touched on the screen depending on whether or not it is touched. The light source drive circuit and the position detection circuit are both provided in one set for detecting the X-axis direction position and one set for detecting the Y-axis direction position.

FIG. 4 is an operation conceptual diagram showing a state in which a finger touching the screen interrupts a light beam that crosses the screen in the optical touch screen device configured as described above.

In the conventional apparatus, in FIG. 4, for example, when the finger enters the light beam from the position A indicated by the broken line and is then removed at the position B indicated by the solid line, the position detection circuit 5
Has been configured to detect the final position B point where the finger is removed as the position designated by the finger.

The position specified by the finger is shifted from the A point position to the B point position because the position where the light beam crosses is slightly apart from the top of the screen and the operation of pulling out the human finger. Is caused by the circular movement of the arm around the elbow (movement of the finger in the upward direction).

<Problems to be Solved by the Invention> For this reason, in the conventional apparatus, there has been a problem that the operator often detects a position on the screen different from the desired position designated on the screen.

The present invention has been made in view of such a problem, and an object thereof is to realize a touch screen device capable of accurately detecting a desired position designated by an operator.

<Means for Solving the Problems> According to the present invention to achieve such an object, a light emitting element is arranged on one side of two pairs facing a touch screen and a light receiving element is arranged on the other side, and the light emitting elements are sequentially emitted. In a touch screen device including a position detection circuit that detects the coordinate position touched on the touch screen from the timing at which the light reaching the light receiving element is blocked, the position coordinate signal obtained from the position detection circuit is output. A first coordinate signal holding means for holding, a delay means for delaying the position coordinate signal from the first coordinate signal holding means for a certain time, and a light beam for detecting whether the light beam crossing the screen is blocked or not. If the beam is blocked, an ON signal is output, and if the light is not blocked, an OFF signal is output. The second coordinate signal holding means for inputting the position coordinate signal from the delaying means and holding the position coordinate signal only when the force is applied, and the ON signal output from the beam breakage detecting means. Selecting means for selecting and outputting the position coordinate signal from the first coordinate signal holding means, and selecting and outputting the position coordinate signal from the second coordinate signal holding means when the OFF signal is output from the beam break detecting means. And are provided.

<Operation> The point where the light beam that crosses the screen is first blocked by the operator's finger is closest to the position coordinate specified by the operator. The second coordinate signal holding means holds the position coordinate signal designated first by a certain time before the operator removes the finger from the light beam, and the selecting means detects the beam disconnection when the finger is removed. Upon receiving the OFF signal from the means, the position coordinate signal held in the second coordinate signal holding means is selected and output. This eliminates the deviation between the position coordinates of the point where the finger is first placed in the light beam and the position coordinates of the point where the finger is removed.

<Embodiment> An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the essential parts of an embodiment of the present invention. In the figure, 1 is a display screen (screen),
21 to 2n are light emitting elements such as LEDs, 31 to 3n are light receiving elements such as phototransistors, and 4 are light emitting elements 21 to 21.
The 2n light emitting element drive circuit 5 is a position detection circuit for inputting signals from each of the plurality of light receiving elements and timing signals from the light emitting element drive circuit 4. Although only one set of systems for detecting the position in the X-axis direction is shown here, it is assumed that a similar circuit is actually provided in the Y-axis direction. These configurations are the same as the conventional ones.

6 is a first coordinate signal holding means for holding the position coordinate signal output from the position detection circuit 5, and 7 is a delay means for delaying the coordinate signal from the first coordinate signal holding means 6 by a predetermined constant time Ta. .

Reference numeral 8 denotes a beam break detecting means for receiving signals from the plurality of light receiving elements 31 to 3n and detecting whether or not a light beam traversing the display screen 1 is blocked by a finger or the like, and 9 denotes this beam break detecting means 8 Is a gate circuit for holding the coordinate signal from the delay unit 7 in the second coordinate signal holding unit 10 when outputting an ON signal indicating beam breakage (a state in which a finger or the like blocks the light beam). Reference numeral 11 is a selecting means for selecting a signal from the first coordinate signal holding means 6 or the second coordinate signal holding means 10 according to the signal from the beam breakage detecting means 8 and outputting it as a coordinate signal.

The operation of the apparatus thus configured will be described below.

FIG. 2 is a diagram showing a state in which a finger enters a light beam that traverses the display screen 1 until the finger exits.

Assuming that the finger is inserted as shown by the broken line, the light beam is blocked at the point A. The position detection circuit 5 first detects the position coordinate XA of the point A. This position coordinate signal X
A is applied to the first coordinate signal holding means 6 and held there.

The position detection circuit 5 detects disconnection of a plurality of light beams from the light emitting element at a constant scanning cycle, and the position coordinate signal updated at a constant cycle is output from here.

The beam break detecting means 8 detects whether or not the finger is inside the light beam, and when the finger is inside the light beam, outputs an ON signal indicating a state where the light beam is blocked.
The selecting means 11 receives this ON signal and selects the position coordinate signal XA held in the first coordinate signal holding means 6,
This is output as a position coordinate signal.

On the other hand, the position coordinate signal XA held in the first coordinate signal holding means 6 is delayed by the delay means 7 for a predetermined time and applied to the gate circuit 9. Upon receiving the ON signal from the beam break detecting means 8, the gate circuit 9 gives the position coordinate signal XA delayed by Ta by the delay means 7 to the second coordinate signal holding means 10 to hold it. Here, the delay time Ta in the delay means 7 is determined in consideration of the time (Tsec) from the time when the finger is put into the light beam to the time when the finger is pulled out.

Next, assuming that the finger moves as shown by the solid line in FIG. 2 and comes off from the point B, the beam breakage detecting means 8 detects that the finger has come off, and from this, the OFF signal indicating this is selected by the gate circuit 9 and the selection. Output to the means 11.

Upon receiving the OFF signal, the selecting means 11 selects the position coordinate signal XA held in the second coordinate signal holding means 10 and outputs it as the position coordinate signal. Further, the gate circuit 9 receives the OFF signal and is in a closed state, and thereafter, the signal from the delay means 7 is not sent to the second coordinate signal holding means 10.

At this point, the first coordinate signal holding means 6 has
The position coordinate signal XB of the point B where the finger is pulled out is held.

In this way, the position designated by the finger is changed from the point A to the point B during the time from when the finger is put into the light beam until when the finger is pulled out.
Even if it moves to the point, the position coordinate signal XA of the point A where the finger is first put (this point is the position closest to the desired position designated on the display screen by the operator) can be always output.

In the above embodiment, the beam breakage detecting means 8 is shown as one block, but this means may be provided in the position detecting circuit 5.

<Effects of the Invention> As described in detail above, according to the present invention, by adding a simple circuit, even if the position where the operator's finger is pulled is different from the desired coordinate position initially specified, It is possible to obtain various position coordinate signals.

[Brief description of drawings]

FIG. 1 is a block diagram showing the construction of an essential part of an embodiment of the present invention, FIG. 2 is a view showing a state in which a finger enters a light beam that traverses a display screen until the finger comes out, and FIG. FIG. 4 is a schematic diagram showing the configuration of a conventional optical touch screen device.
FIG. 9 is an operation conceptual diagram showing how a light beam that crosses the screen is blocked by a finger touching the screen in the optical touch screen device configured as shown in the figure. 1 ... Display screen (screen) 21-2n ... Light emitting element, 31-3n ... Light receiving element 4 ... Light emitting element drive circuit, 5 ... Position detection circuit 6 ... First coordinate signal holding means 7 ... Delay means, 8 ... Beam disconnection detection means, 9 ... Gate circuit, 10 ... Second coordinate signal holding means, 11 ... Selection means

Claims (1)

[Scope of utility model registration request] 1. A light emitting element is arranged on one side of two pairs of sides facing a touch screen, and a light receiving element is arranged on the other side, and the light emitting elements are made to sequentially emit light so that the light reaching the light receiving element is blocked from the timing of touching. In a touch screen device including a position detection circuit that detects a coordinate position touched on the screen, a first coordinate signal holding unit that holds the position coordinate signal obtained from the position detection circuit, and the first coordinate A delay means for delaying the position coordinate signal from the signal holding means for a fixed time, and whether or not the light beam that crosses the screen is blocked is detected. If the light beam is blocked, the ON signal is output, and the light is not blocked. In this case, the beam disconnection detecting means for outputting an off signal and the position coordinate signal from the delay means are output only when an on signal is output from the beam disconnection detecting means. Second coordinate signal holding means for inputting and holding the position coordinate signal, and when the ON signal is output from the beam break detecting means, selects and outputs the position coordinate signal from the first coordinate signal holding means. And a selection means for selecting and outputting the position coordinate signal from the second coordinate signal holding means when an off signal is output from the beam breakage detecting means.