JPH02201526A - Method for reading in light reception output signal of optical touch panel - Google Patents

Abstract

PURPOSE:To increase the sweep speed by reading the light reception output signal of one unit optical system in each of plural unit optical system groups into a storage device in the case of a signal level for light non-emission and reading light reception output signals of all unit optical systems in the group into the storage device in the case of a signal level for light emission. CONSTITUTION:An optical touch panel consists of a light emitting element array 11, a photodetector array 12, a display device 13, and a light shielding material 14. Plural unit optical systems constituting the light emitting element array 11 and the photodetector array 12 are divided into plural groups and are swept, and the light reception output signal of one of plural unit optical systems of each group is read into the storage device in the case of the signal level for light non-emission, and light reception output signals of all unit optical systems of the group are read into the storage device in the case of the signal level for light emission. Thus, the sweep speed is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of reading a light reception output signal of an optical touch panel into a storage device.

[Conventional technology]

FIG. 2a is an explanatory diagram of the optical touch panel.

In FIG. 2a, 11 is a light emitting element array, Ila is a light emitting element, 12 is a light receiving element array, 12a is a light receiving element, 13 is a display, and 14 is a light shielding object.

The optical touch sensor has a display unit 1 as shown in Figure 2a.
A light emitting element row 11 in which a large number of infrared light emitting elements 11th are arranged around the display surface of 3, and a large number of infrared light receiving elements 1.
A light-receiving element row 12 in which light-receiving elements 2a are arranged is arranged horizontally and vertically to face each other, and a light-emitting element 11h and a light-receiving element 1 are arranged facing each other.
2a are sequentially swept in the horizontal and vertical directions, and the received light output signal level is stored for each unit optical system when the light emitting element is not emitting light and when it is emitting light. A device that reads the information into the device, compares the levels, detects the orthogonal coordinates of the position of the light-shielding object 14 touched at the intersection of the infrared ray matrix formed on the display surface of the display 13, and outputs the position information. It is.

FIG. 2 is an explanatory diagram of the configuration of the unit optical system, where lla is a light emitting element, 12a is a light receiving element, 15a and 15b are analog switches, 16 is an amplifier, 17 is a load resistor, and 18 is a light receiving output signal. When this unit optical system receives a sweep signal,
First, the analog switch 153 is turned on, and the light receiving element 12h is brought into operation. Next, analog switch 15
When b is closed for a certain period of time, the light emitting element 11h emits light, and when the light receiving element 12m receives the light, a current flows through the load resistor 17, and the voltage generated is transmitted to the amplifier 16 and amplified to produce a light reception output signal. Output as 18.

This light reception output signal 18 is caused by pulse noise caused by a transient current when the analog switch 15h is turned on, dark current of the light reception element 12 and disturbance when the light reception element 12a is activated, even if the light emitting element 11m is not emitting light. It includes a low level signal generated when a current due to light flows through the load resistor 17 and a high level signal generated when the light emitting element 11h emits light.

Of these signals, the low-level signal and high-level signal are read into a storage device (not shown) at a certain timing, but conventionally, the signals are first read after waiting for the noise to decay. It was reading a low level signal and then a high level signal.

FIG. 3 is a conventional reading time chart of the light reception output signal 18 shown in FIG. In FIG. 3, (a) is a nozzle that drives the analog switch 15a.

(b) is a Noculus that drives the analog switch 15b.

(C) is the waveform of the received light output signal 18 (in the figure, tw is the reading timing time) is the low level signal reading/main pulse. (E) Is it high level signal reading? It's Luz.

A large number of unit optical systems arranged horizontally and vertically around the display surface of the display unit are moved vertically by sweeping, the light-receiving element is activated by the pulse in (a), and the light-emitting element is activated by the pulse in (b). The pulse of (a), which occurs when the analog switch 15m is connected due to the 9 pulses, is emitted after the period of time jw has elapsed until the pulsing noise attenuates and reaches a steady state. The low-level signal is read into the storage device and then emitted, and the high-level signal is read into the storage device by the Noculus (e).

As described above, in the conventional method of reading the light reception output signal of an optical touch panel into a storage device, a low level signal is read before a high level signal is read.

[Problem to be solved by the invention]

As mentioned above, the optical touch panel arranges a large number of unit optical systems around the display surface of the display device, sweeps them to form an infrared ray matrix, and touches the display surface to emit the infrared rays. It is used by being incorporated into a system that detects the orthogonal coordinates of the position of a light-blocking object, outputs the position information, and obtains a response from the conbeater that receives this information, so a fast detection speed is required. be done. However, conventionally, as mentioned above, the pulse noise generated when driving the light receiving element of the unit optical system is attenuated, and the low level signal of the light receiving output signal is read after a period of time until the steady state is reached, and then the light is emitted. It drove the elements and read high-level signals. This period of time occupies a considerable amount of the time required to read the light receiving output signal of the unit optical system, so it is not possible to increase the sweep speed or increase the speed of detecting the position of the touched object. 3゜The present invention is not affected by the above-mentioned pulse noise,
It is an object of the present invention to provide a method for reading a received light output signal that can read a low level signal to increase the sweep speed and increase the detection speed.

[Means to solve the problem]

In order to solve the above problems, the present invention divides a plurality of unit optical systems forming the light emitting element row and the light receiving element row into a plurality of groups including an arbitrary number of the unit optical systems. The groups are sequentially swept, and the respective levels of the light reception output signal when the unit optical system is not emitting light and when it is emitting light are read into the storage device for each group. The measurement is performed for each unit optical system, and the signal level at the time of light emission is determined for all the unit optical systems included in the group to increase the sweep speed and the detection speed.

[Effect]

As described above, the present invention divides a plurality of unit optical systems into a plurality of groups, reads the received light output signal of the unit optical system into a storage device for each group, and sets the signal level of the unit optical system in the group when no light is emitted. This was done for only one unit optical system, and the signal level at the time of light emission was determined for all unit optical systems included in the group, so it is possible to reduce the r/Grus characteristics that occur when switching and driving the unit optical system by sweeping. The noise attenuation is only timed when reading the signal level when no light is emitted, and the signal level when light is emitted can be read immediately after switching, making it possible to significantly increase the sweep speed.

〔Example〕

Embodiments of the present invention will be described with reference to FIG. 1 and FIG. 2. FIG. 1 is a time chart of one embodiment of the present invention. That is, in addition to forming the light emitting element array and the light receiving element array shown in FIG. It shows the time relationship when dividing, sweeping and driving to obtain a light reception output signal and reading the signal levels in the non-emission state and in the emission state into the storage device.

In the embodiment shown in FIG. 1, the large number of unit optical systems is divided into m groups, each group is made up of n unit optical systems, and the signal when the light is not emitted among the light receiving output signals of the light receiving element is This is a case where the reading of the level is performed only for the first unit optical system for each group, and the reading of the signal level at the time of light emission is performed for all of the n unit optical systems that make up the group. .

In FIG. 1, (a) shows the light receiving element driving pulse and the light emitting element driving pulse of the first unit optical system of each group (1 to m). Hereinafter, (b), r-t, and b) indicate the second, n1th, and nth drive pulses, respectively. (E) is the light receiving output signal of all light receiving elements, (F)
is a pulse that reads the signal level when no light is emitted into the storage device,
(g) is a signal that reads the light reception output signal level at the time of light emission into the storage device.

The length of the light-receiving element drive loop of the first unit optical system in (a) is set to a time that allows the signal level when no light is emitted and the signal level when light is emitted to be read into the storage circuit.

That is, the first unit optical system is swept, and the light receiving element driver I
When the light receiving element is driven by the #JJ pulse, the second
When the analog switch 15a shown in FIG. Then, the signal level is read into the storage device using the signal level reading pulse during non-emission shown in FIG.
4) Drive the light emitting element to emit light, and read the signal level when emitting light as shown in Figure 1 (g). The level of the light reception output signal at the time of light emission is read into the storage device.

As described above, the present invention divides a plurality of unit optical systems into a plurality of groups, and calculates the signal level when no light is emitted read in one unit optical system in one group, and the signal level of all the unit optical systems in the group. This method detects the presence or absence of a light-blocking object by comparing the level of the received light output signal when emitting light.
Simply drive the light-emitting element and read the level of the light-receiving output signal when emitting light, without waiting for the nozzle noise generated when each unit optical system is swept-driven to sufficiently attenuate. Therefore, the length of the light-receiving element drive/guru can be shortened. Therefore, compared to the conventional method of alternately reading the light reception output signal level when no light is emitted and when the light is emitted for each unit optical system, the sweep speed can be significantly increased. Note that the reading of the signal level when no light is emitted is not limited to the first unit optical system of each group as in the above embodiment;
It goes without saying that any one of the numbers .about.mth is fine.

Further, the number of unit optical systems constituting the group may be changed in the horizontal direction and the vertical direction, or may be changed between the ends and the center in each of the directions.

〔Effect of the invention〕

As described above in detail, according to the present invention, a plurality of unit optical systems forming the light emitting element array and the light receiving element array of the optical touch Zener are divided into a plurality of groups and swept, and the light reception output signal is stored. The signal level when no light is emitted is read into the device for one of the multiple unit optical systems that make up the group, and the signal level when light is emitted is read for all the unit optical systems that make up the group. This has the effect that the sweep speed can be increased, and therefore the detection speed can be increased. Furthermore, even if the brightness of the ambient light incident on the light receiving element array of the optical touch panel differs depending on the location of the light receiving element array, for each group Since the signal level difference can be detected, the effect of accurately detecting the presence or absence of a light blocking object can be expected.

[Brief explanation of the drawing]

Fig. 1 is a time chart of an embodiment of the present invention, Fig. 2a
is an explanatory diagram of the optical touch control, Figure 2 is Figure 2a
FIG. 3 is a conventional reading time chart of the received light output signal 18 shown in FIG. 2. 1 No. Light emitting element row, l1m... Light emitting element, 12.
... Light receiving element row, 12a... Light receiving element, 13... Display, 14... Light blocking object, 15a, 15b... Analog switch, 16... Amplifier, 17... Load resistor, 18 ...Light reception output signal. Patent applicant: Minato Electronics Co., Ltd. Explanatory diagram of optical touch gunnel Figure 2 Q Imvec +VCC Explanatory diagram of the configuration of the unit optical system in Figure 2 a (a) Analog switch 15a drive pulse Figure 2 Light reception output of Conventional reading time chart of signal 18

Claims (1)

[Claims] (1) A light-emitting element row and a light-receiving element row are disposed horizontally and vertically opposite to each other around the display surface of the display device, and a single light-emitting element facing each other forms both the element rows. A plurality of unit optical systems in which the light receiving element and the light receiving element work together are sequentially swept and driven in the horizontal and vertical directions to form an optical matrix, and the respective levels of the light receiving output signal when no light is emitted and when light is emitted are memorized. In the method for reading a light reception output signal of an optical touch panel, the plurality of light reception output signals are read into a device, the signal levels are compared, the orthogonal coordinates of the position of a light-blocking object that is touched on the display surface are detected, and the position information is outputted. The unit optical system is divided into a plurality of groups including an arbitrary number of unit optical systems, the groups are sequentially swept, and both signal levels to be compared in order to perform the detection are read into a storage device. , for each group, the signal level when not emitting light is determined for one unit optical system in the group, and the signal level when emitting light is determined for all unit optical systems included in the group. How to read the light reception output signal of an optical touch panel.