JP2003337658A - Light scanning touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light scanning touch panel, which can detect the extent of the influence of disturbance light, and can prevent the situation in which an accurate calculation result cannot be acquired due to the disturbance light. <P>SOLUTION: In a state in which during a predetermined time clocked with a timer, an off signal is outputted from an MPU 5 to light-emitting element drive circuits 2a (2b) and the light-emitting operation of a light-emitting elements 11a (11b) is halted, a polygon mirrors 16a (16b) is rotated. The maximum value and the minimum value of the received light output from light-emitting elements 13a (13b) in the meantime are detected with the MPU 5. The difference in the maximum value and the minimum value is sought, and the difference is compared with a reference value. If the difference is large, disturbance light (panel light or the like) which affects the calculation operation of the light scanning touch panel exists, and if the difference is small, the disturbance light which affects the calculation operation does not exist. Thereby, the extent of the influence of the disturbance light on the calculation operation of the light scanning touch panel is detected. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION [0001] The present invention relates to a computer system.
On the display screen of the display device on which information is displayed
Optical scanning type that optically detects the position and size of the pointer
Related to touch panels. 2. Description of the Related Art Computers such as personal computers
With the spread of computer systems, computer systems
The person on the display screen of the display device on which information is displayed by the system
By pointing with your finger or a specific indicator,
Enter information or send information to a computer system.
Devices for giving various instructions are used. [0003] Tables of such personal computers and the like
Touch method for the information displayed on the display screen of the display device
When performing an input operation, touch on the display screen.
It is necessary to detect the position (pointed position) with high accuracy. this
To detect the indicated position on the display screen with such a coordinate plane
As a law, "Carroll system" is known (for example,
See Patent Document 1. ). This method uses the border on the front of the display screen.
The light emitting element and the light receiving element are
Form a matrix of light on the front of the display screen, finger or
The position where light is blocked by pen contact is detected. This one
Method, high S / N can be obtained and applied to large display devices.
Although it is possible to expand, the light emitting element and the light receiving element
The resolution of detection is proportional to the spacing between
In order to improve the performance, it is necessary to narrow the spacing
You. Therefore, use a thin object such as a pen tip for a large screen.
In order to accurately detect the contact position even if it touches
Increases the number of light emitting elements and light receiving elements to be arranged,
The structure becomes bulky and the signal processing becomes complicated
There's a problem. Another optical position detecting method has been disclosed.
(For example, see Patent Document 2). This method
Focusing light such as a laser beam from the outside of the display screen at an angle
Two of the reflected light from a dedicated pen that scans and has reflective means
The angle at which the dedicated pen exists from the timing of
Position coordinates by applying the obtained angle to the principle of triangulation.
Is detected by calculation. This method greatly reduces the number of parts
It is possible to have a high resolution.
You. However, a special reflective pen must be used.
There is a problem in operability such as no
Cannot be detected. [0005] Still other optical position detection methods have been proposed.
(For example, see Patent Document 3). This method uses a table
Position the light retroreflector on both sides of the display screen and scan the angle.
Of the returning laser beam from this retroreflector
When the light is blocked by a finger or pen
From the angle of the finger or pen, and
Position coordinates are detected based on the principle of angular survey. in this way,
The number of parts is small and the detection accuracy can be maintained.
The position of the button can be detected. In addition, it is not only the position of a finger, an arbitrary pen or the like.
Optical detection method that also detects the size
Has been proposed by the same applicant as the present invention (for example,
See Patent Document 4. ). This method is almost parallel to the display screen
At least two light sources for angularly scanning a laser beam in a plane
Place the receiver in the corner of the display screen and at least
A light retroreflector is provided along three sides, and
Measures the scanning light blocking range with an indicator such as a finger or pen,
The position of the pointer in the scanning plane is determined by the principle of triangulation.
In addition to the calculation, the size of the indicator is also calculated. [Patent Document 1] US Patent No. 4,267,443 [Patent Document 2] Japanese Patent Application Laid-Open No. 57-2111637 [Patent Document 3] Japanese Patent Application Laid-Open No. Sho 62-5428 [Patent Document 4] SUMMARY OF THE INVENTION Problems to be Solved by the Invention Light is scanned angularly.
The above three conventional examples have a plurality of light reflecting surfaces.
The polygon mirror is rotated to realize angular scanning of light.
You. And the light from the light retroreflector during angular scanning of light
Return light is detected, and the detection level is adjusted to a predetermined threshold level.
The light beam is blocked by a finger or pen
Detected as a cutoff range. Such an optical scanning type touch
Panel is not affected by disturbance light such as illumination light.
And many. However, in the conventional example, the state of disturbance light
The calculation operation is performed without considering
Environment is not determined.
There is a problem that accurate calculation results cannot be obtained due to
You. The present invention has been made in view of such circumstances.
The degree of the influence of the disturbance light can be detected, and the
Scanning that can prevent situations where accurate calculation results cannot be obtained
It is intended to provide a type touch panel. [0010] An optical scanning type touch panel according to the present invention is provided.
The touch panel emits light in a plane substantially parallel to the predetermined area.
An optical scanning unit for angularly scanning the light,
An optical element and a scanning light formed by an indicator in the predetermined area.
The cutoff position is determined based on the output of the light receiving element corresponding to the scan angle.
Scanning type touch panel with a measuring unit
And means for turning off the scanning light and counting a predetermined time.
And a scanning light for the predetermined time measured by the timer.
Is turned off and the optical scanning unit is activated,
Calculates the difference between the maximum value and the minimum value of the light receiving result at the light receiving element
Calculating means, and a difference calculated by the calculating means and a predetermined basis.
Comparing means for comparing with a quasi-value.
You. In the optical scanning type touch panel according to the present invention, the predetermined
Turn off the scanning light over time to activate the light scanning unit,
The difference between the maximum value and the minimum value of the light receiving result of the light receiving element during that time
Is obtained, and the obtained difference is compared with a predetermined reference value. This difference
When it is large, the influence of disturbance light is large, and this difference is small.
In such a case, it is considered that the influence of disturbance light is small. Therefore,
By calculating the difference and comparing it with the reference value, the disturbance light
The degree of influence can be detected. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to its embodiments.
This will be specifically described with reference to the drawings shown. FIG. 1 shows the present invention.
FIG. 2 is a schematic diagram illustrating a basic configuration of an optical scanning type touch panel.
You. In FIG. 1, reference numeral 10 denotes a personal computer.
CRT or flash in electronic devices such as computers
Display panel (PDP, LCD, EL, etc.)
It is a display screen of a projection type video display device or the like, and in the present embodiment,
Is 92.0 cm (horizontal) × 51.8 cm (vertical) and 10 diagonal
PDP having a display size of 5.6 cm (plasma display)
Play) display screen. An indicator (blocking object) such as a finger or a pen
Flat area defined as target area for touching by S
One short side of this rectangular display screen 10 that is the area of the surface
Outside of both corners (right side in this embodiment)
Built-in optical system including element, light receiving element, polygon mirror, etc.
Optical transmission / reception units 1a and 1b provided in
ing. Also, three sides excluding the right side of the display screen 10
In other words, retroreflection is on the outer sides of the upper and lower sides and the left side.
A seat 7 is provided. These parts are located on the front of the housing
Shielded by an eaves-shaped shield (not shown) installed on the side
It is arranged in the state where it was done. Reference numeral 70 denotes a light shielding member.
The light shielding member 70 is provided between the two light transmitting / receiving units 1a and 1b.
To prevent direct light from entering the
The light projected from the unit 1a enters the light transmitting / receiving unit 1b
From the optical transmission / reception unit 1b
So that the emitted light does not enter the light transmitting / receiving unit 1a.
It is provided on a line connecting the two light transmitting and receiving units 1a and 1b.
You. Also, the light shielding member 70 has a light reflectance of practical use.
0 ", which is almost the same as the height of the retroreflective sheet 7.
It is configured to the same height. FIG. 2 shows the inside of the optical transmission / reception units 1a and 1b.
It is a schematic diagram which shows a structure and an optical path. Both light transmitting and receiving unit 1
a and 1b are laser diodes emitting infrared laser light.
Light-emitting elements 11a and 11b
a, collimation for converting the laser light from 11b into parallel light
From the data lenses 12a and 12b and the retroreflective sheet 7
Light receiving elements 13a and 13b for receiving reflected light of
From display screens, illumination lights, etc., which are incident on the children 13a and 13b.
Light cut filter that blocks the visible light component of external light
14a, 14b and reflected light to the light receiving elements 13a, 13b.
Beam splitters 15a and 15b for guiding the light,
For angularly scanning the laser beams from the elements 11a and 11b
For example, a polygon mirror having a quadrangular prism shape is provided.
I do. The rotation of the polygon mirrors 16a and 16b
This realizes angular scanning of light of 90 degrees or more. Light receiving element 1
3a and 13b are polygons at the start of each scan.
Receiving laser light scanned from mirrors 16a and 16b
The timing of the synchronization signal is determined by
For correcting the rotational speeds of the mirrors 16a and 16b
Used to generate The light emitted from the light emitting elements 11a and 11b
Laser light is collimated by the collimator lenses 12a and 12b.
And passes through beam splitters 15a and 15b described later.
After the rotation, the polygon mirrors 16a and 16b rotate
Angle scanning in a plane substantially parallel to the display screen 10.
And projected on the retroreflective sheet 7. And recursive
Light reflected from the reflection sheet 7 is reflected by the polygon mirror 16a,
16b and reflected by the beam splitters 15a and 15b.
After passing through the visible light cut filters 14a and 14b.
Then, the light enters the light receiving elements 13a and 13b. However, projection
When the indicator S exists in the optical path of the light, the projection light is blocked.
Therefore, the reflected light enters the light receiving elements 13a and 13b.
Never. Each light transmitting / receiving unit 1a, 1b has a light emitting element.
Light emitting element driving circuits 2a, 2 for driving the elements 11a, 11b
b and the light receiving amounts of the light receiving elements 13a and 13b are converted into electric signals.
Light receiving signal detecting circuits 3a and 3b to be replaced and a polygon mirror
A polygon control circuit 4 for controlling the operations of 16a and 16b;
Is connected. Reference numeral 5 indicates the position of the pointer S.
And size, and control the operation of the entire device.
MPU 6 displays the calculation results and the like in MPU 5
Display device. Such an optical scanning type touch panel of the present invention.
In FIG. 1, as shown in FIG.
The unit 1b will be described.
The projection light from the scanning opening is directly incident on the light receiving element 13b.
From the starting position through the position shielded by the light shielding member 70
Retroreflective sheet scanned counterclockwise on FIG.
7 reaches a position (Ps) where the light is reflected at the tip portion. Soshi
Until the position (P1) reaching one end of the pointer S
Reflected by the retroreflective sheet 7, the other end of the pointer S
Until the position (P2) leading to
Retroreflected until the scanning position (Pe)
The light is reflected by the sheet 7. However, in the optical transmission / reception unit 1a, in FIG.
Light scanning is performed in a clockwise direction. Here, the optical transceiver
The knit 1a is clockwise below the display screen 10 in FIG.
The side is the scanning start direction, and the light transmission / reception unit 1b is
1. Open the upper side of the display screen 10 in the counterclockwise direction on 1
The reason for the start direction will be described. In the case of the light transmitting / receiving unit 1b, a display screen
10 Either the upper side or the left side is the scanning start direction.
However, when viewed from the optical transmission / reception unit 1b, the display image
Reflection because the upper side of the surface 10 is closer in distance than the lower side
A large amount of light, and the reflective surface of the retroreflective sheet 7
Is almost right angle on the upper side of the display screen 10 so that the reflected light
Because the amount is large, the upper side of the display screen 10 is scanned.
Start direction. In other words, the light transmitting / receiving unit 1b
, The lower side of the display screen 10 is set as the scanning start direction.
, The lower side of the display screen 10 is farther in distance than the upper side
As a result, the amount of reflected light at the start of scanning becomes smaller, and
The amount of reflected light because the reflective surface of the reflective sheet 7 is curved
Becomes smaller. However, regarding the curvature of the retroreflective sheet 7,
Is not an essential problem, and a configuration that does not bend
Of course, it is also possible to take. By the way, as shown in FIG.
The retroreflective sheet 7 has the two light transmitting / receiving units 1a and 1b.
The side that is set as an opening so that it surrounds the display screen 10
Are arranged in a “U” shape. Further, reference numeral 7
a, 7b, both light transmitting and receiving units 1
a, 1b, the projection angle of light from retroreflective sheet 7 to small
A portion to be reduced, specifically, both light transmitting and receiving units 1a and 1b
Are arranged at right angles to two sides (in FIG. 1, the upper side
Far from both the light transmitting and receiving units 1a and 1b).
A retroreflective sheet is provided in a sawtooth shape on the portion. The saw-toothed portion of such a retroreflective sheeting
7a and 7b, for example, from the light transmitting / receiving unit 1b.
The light is emitted from the position of Ps to the sawtooth portion 7 of the retroreflective sheet.
Retroreflection as scanning proceeds to position P3 at one end of b
Since the angle of incidence on the sheet 7 gradually decreases, the amount of reflected light
Also decrease accordingly. However, the retroreflective sheet
From the position P3 of one end of the serrated portion 7b to the position P4 of the other end thereof.
Is substantially perpendicular to the serrated portion 7b of the retroreflective sheeting.
Incident on the laser, avoiding further reduction in retroreflectivity
It is. FIG. 3 shows the relationship between the MPU 5 and other circuits.
FIG. The polygon control circuit 4
Pulse motor 21 for rotating mirrors 16a and 16b
And a pulse motor drive circuit for driving the pulse motor 21
22. The MPU 5 includes light emitting element drive circuits 2a, 2b
To the drive control signal, and emit light according to the drive control signal.
The element driving circuits 2a and 2b are driven to drive the light emitting element 11
The light emission operations of a and 11b are controlled. And the off signal
Is output from the MPU 5 to the light emitting element drive circuits 2a and 2b.
While the light emitting elements 11a and 11b stop emitting light.
As a result, laser light is emitted from the light emitting elements 11a and 11b.
Not to be. The light receiving signal detecting circuits 3a and 3b are light receiving elements.
Sends the light receiving signal of the reflected light at 13a, 13b to MPU5
You. The MPU 5 receives light receiving signals from the light receiving elements 13a and 13b.
The position and size of the pointer S are calculated based on the
The calculation result is displayed on the display device 6. In addition, the display device 6
The display screen 10 can also be used. Also, MP
U5 is based on the light receiving signals from the light receiving elements 13a and 13b.
Then, the optical scanning start timing is detected. Furthermore, MPU
5 is a drive control signal for driving the pulse motor 21
To the pulse motor drive circuit 22. The MPU 5 calculates the position and size of the pointer S.
Read-only memo that stores the algorithm of the output procedure
(ROM) 25, values in the middle of the calculation procedure, and indicators
Measure the position of S, the calculated value of the size, and the cutoff range of the scanning light
Writable memory for storing threshold values for
(RAM) 26 and timing of detected optical scanning start
And a timer 27 for measuring a predetermined time from the time. FIG. 4 shows an example of the configuration of the light receiving signal detection circuit 3a.
FIG. The light receiving signal detection circuit 3b also receives the signal.
The configuration is the same as that of the optical signal detection circuit 3a.
Will be described by substituting "b" for "a" at the end of the reference numeral. The light receiving element 13a determines the amount of received light in proportion to the current value.
Current / voltage (I /
V) Output signal from light receiving element 13a by converter 30a
(Current) into a voltage signal. Current / voltage converter 30
The voltage signal output from the low-pass filter 31a
The amplifier 32a passes through one of the comparators 33a.
The signal is input to the input terminal as a signal to be compared. This con
The output of the parator 33a is input to a first timer 34a.
The output is input to the MPU 5. Amplifier 3
The output of 2a is also provided to A / D converter 36a.
And converted into a digital signal and input to the MPU 5.
The other input terminal of the comparator 33a has MP
The digital signal output from U5 is a D / A converter 35a
Is converted to an analog signal and the comparison threshold value Ref
Is entered as This threshold Ref will be described later.
Thus, the setting is performed by the MPU 5. Further, the output of the low-pass filter 31a is
One input terminal of the comparator 38a via the amplifier 37a
Input to the slave as a signal to be compared. This comp
The output of the radiator 38a is input to a second timer 39a.
The output is input to the MPU 5. In addition,
The threshold value TH for comparison of the parator 38a is detected by timing.
Between the maximum output at the time and the maximum output at the indication position detection
Level is set. The light receiving signal detection circuit 3a having such a configuration
(The same applies to 3b) and the operation of the MPU 5 will be described.
The threshold value TH for comparison in the comparator 38a is
Maximum output at the time of detecting the imming and maximum output at the time of the indication position detection
And the comparator 38a receives the signal
The optical element 13a is a light directly reflected from the polygon mirror 16a.
Outputs a signal "1" only during the period when
In other periods, the signal “0” is output. Follow
Therefore, the output signal of the comparator 38a changes from "0" to "0".
The timing of rising to 1 "is the timing of the start of optical scanning.
It becomes. The second timer 39a includes a comparator 38a
Output signal rises from "0" to "1"
(Time to start optical scanning)
Rise from "0" to "1"
The timing operation is continued until the start timing). That is, the second
Timer 39a is reset at each optical scanning start timing
And the measurement result is output to MPU5.
You. Thus, the second timer 39a uses the comparator
Time when the output signal of 38a rises from "0" to "1"
Interval (time interval from start of optical scanning to start of next optical scanning)
, The rotation of the polygon mirror 16a is
You can monitor your condition. The output of the amplifier 32a is an A / D converter 36a
Is converted into a digital signal and input to the MPU 5
Therefore, the MPU 5 operates the light receiving element 13a during a certain period.
Output signals can be monitored as digital signals
It is. The MPU 5 sends a digital signal to the D / A converter 35a.
Output the analog signal and convert it to an analog signal.
To the other input terminal of the comparator 33a.
It is possible to give. Then, the comparator 33a
Is the threshold given by the output of the amplifier 32a and the MPU5.
Ref, and the output of the amplifier 32a
If it is more than the above, "1" is output.
0 ". The first timer 34a outputs
The duration of the “1” output and “0” output from the
Time measurement is performed, and the time measurement result is output to the MPU 5. Next, according to the optical scanning type touch panel of the present invention.
The operation of calculating the position and size of the pointer S will be described.
You. FIG. 5 is a schematic diagram showing an implementation state of the optical scanning type touch panel.
FIG. However, in FIG. 5, the light transmitting / receiving units 1a, 1
b, components other than the retroreflective sheet 7 and the display screen 10
Is not shown. Also, using a finger as the pointer S
Shows the case where The MPU 5 controls the polygon control circuit 4.
As a result, the polygon mirrors in the light transmitting / receiving units 1a and 1b are
By rotating the mirrors 16a, 16b, the light emitting elements 11a, 1
The laser beam from 1b is angularly scanned. This results in recursive
Light reflected from the reflection sheet 7 is transmitted to the light receiving elements 13a and 13b.
Incident. Thus, the light enters the light receiving elements 13a and 13b.
The received light amount of the emitted light is the output of the light reception signal detection circuits 3a and 3b.
Is obtained as a light receiving signal. In FIG. 5, θ00 and φ00 represent both optical transmissions.
From the reference line connecting the receiving units 1a and 1b to the light emitting element 11
a, 11b are transmitted from the polygon mirror 16a, 1
6b directly reflects and enters the light receiving elements 13a and 13b
The angles θ0 and φ0 connect the two light transmitting and receiving units 1a and 1b.
The angle from the reference line to the end of the retroreflective sheet 7 is
θ1 and φ1 are the distance from the reference line to the end of the pointer S on the reference line side.
The angles θ2 and φ2 are opposite to the reference line of the pointer S from the reference line.
The angle to the side end is shown. FIG. 6A shows a case where the pointer S does not exist.
And waveform of light receiving signal by light receiving element 13a
FIG. 6 shows a waveform of the threshold Ref in the data 33a.
(B) shows the comparison output by the comparator 33a at that time.
4 shows a waveform of a force signal. In the case of the optical transmission / reception unit 1b
The same applies to this. When the scanning angle is θ00 (φ00), the light receiving element
13a (13b) is directly from the light emitting element 11a (11b)
Receive light. This state corresponds to the output signal of the comparator 38a.
Is detected as the timing when “0” changes to “1”.
And the cycle is counted by the second timer 39a.
You. This allows the MPU 5 to operate the polygon mirror 16a.
Since the rotation cycle of (16b) can be monitored, rotate it
The correction of the rotation of the pulse motor 21
This is performed by controlling the polygon control circuit 4 first. Ma
In addition, from the start of optical scanning, the timer 27 in the MPU 5
A predetermined elapsed time is measured. It should be noted that a polygon mirror as in this embodiment is used.
If 16a (16b) is a regular polygon with four faces,
In one cycle measured by the second timer 39a, the polygon
This means that the rotator 16a (16b) has rotated １ ／. When no indicator S exists in the optical path of the scanning light
Is the timing of θ00 (φ00) shown in FIG.
Input to the light receiving element 13a (13b)
After the radiation, the reflected light from the retroreflective sheet 7 is received by the light receiving element.
13a (13b). From the retroreflective sheet 7
As shown in FIG. 6A, the amount of reflected light
Of the retroreflective sheet 7 at an angle of θ0 (φ0)
Is the largest because it receives reflected light from nearby parts.
After that, the farthest diagonal of the retroreflective sheet 7 gradually decreases
Once at the corner in the direction, then gradually increase to 90 °
At one angle, and one cycle of scanning is completed. By the way, the comparator 33a has a threshold value.
When Ref is set, the MPU 5
The output signal of “a” is “1”, in other words, the comparator
33a is equal to or higher than the threshold value Ref.
Of the time measured by the first timer 34a that measures the time
You. If the device is normal, the direct
Relatively short "1" output and recurrence due to incident light
A relatively long time caused by the light reflected from the reflection sheet 7 "
1 "output is obtained as an output signal of the comparator 33a.
It is. However, it is caused by the light directly incident on the light receiving element 13a.
The "1" output for a relatively short time is output by the second timer 39a.
Since it is synchronized with the clock cycle, it is shown in FIG.
As described above, the MPU 5 reflects light reflected from the retroreflective sheet 7.
Only the duration of the relatively long "1" output due to
The measured time is stored in the RAM 26. FIG. 7A shows a case where the pointer S exists.
Waveform of light receiving signal by light receiving element 13a and comparator
FIG. 7 shows a waveform of the threshold Ref at 33a.
(B) shows the comparison output by the comparator 33a at that time.
4 shows a waveform of a force signal. In the case of the optical transmission / reception unit 1b
The same applies to this. The indicator S is placed on the optical path of the scanning light on the display screen 10.
Is present, the light is transmitted and received from the optical transmission / reception units 1a and 1b.
The reflected light of the emitted light from the indicator S is received by the light receiving element 13a,
13b. Therefore, it is shown in FIG.
In such a state, when the scanning angle is between 0 ° and θ0,
No reflected light is incident on the optical element 13a, and the scanning angle is θ0.
Between θ and θ1, reflected light is incident on the light receiving element 13a.
When the scanning angle is between θ1 and θ2, the light receiving element 13
No reflected light is incident on a. Similarly, if the scan angle is 0 °
From φ0 to φ0, the reflected light is not incident on the light receiving element 13b.
The light receiving element 1 is not provided when the scanning angle is between φ0 and φ1.
3b is reflected light and scanning angle is from φ1 to φ2
The reflected light does not enter the light receiving element 13b during the interval. Such angles are shown in FIGS. 7A and 7B.
Comparison between the light receiving signal level and the threshold value Ref as shown in FIG.
As a result, in other words, the rising or falling of the received light signal
It is determined from the timing of the beam (FIGS. 8A and 8B).
reference). Therefore, the range of interruption by the finger of the person as the indicator S is
Is determined as dθ = θ2-θ1, dφ = φ2-φ1
Can be Note that θ00 and φ00 and θ0 and φ0 are
A reference line connecting the two light transmitting / receiving units 1a and 1b and the light receiving element 1
Positional relationship with 3a, 13b and end of retroreflective sheet 7
Needless to say, it is known from the positional relationship of the parts. Here, the optical scanning type touch panel of the present invention
Threshold Ref for detecting the range of cutoff of scanning light by
Will be described. In the case of light scanning, a signal which falls below the threshold Ref is received.
When the light level is not detected, that is, when there is no indicator S
If determined, during a predetermined time period measured by the timer 27
Then, the MPU 5 turns off the light emitting element drive circuit 2a (2b).
A signal is output, and the light emitting element 11a (11b) emits light.
To stop. During this time, the MPU 5 changes the A / D
The light receiving element 13a (13
b) adding a predetermined value (margin voltage) to the light receiving output,
The digital addition value is output to the D / A converter 35a.
The D / A converter 35a is a digital converter output from the MPU 5.
Signal to an analog signal and output to the comparator 33a.
Threshold value (reference voltage) Ref for comparison output
To set. Note that this margin voltage is
Fluctuation of received light due to noise, digital data during A / D conversion
Based on ring error, accumulated time-series received light data, etc.
Is determined. The MPU 5 performs the following operation.
Of the disturbance light for the calculation operation of the optical scanning touch panel
Detect the degree of impact. Predetermined time measured by timer 27
Between the MPU 5 and the light emitting element drive circuit 2a (2b)
An off signal is output to emit light from the light emitting element 11a (11b).
With the operation stopped, the polygon mirror 16a (16
b) is rotated. During this time, the A / D conversion
The light receiving element 13a (13
The maximum value and the minimum value in the light receiving output of b) are
To detect. The difference between the maximum value and the minimum value is calculated, and the difference is calculated.
Is compared with a reference value, and the comparison result is output. When the difference between the maximum value and the minimum value is large,
Greatly affects the calculation operation of the optical scanning touch panel.
When there is disturbance light (illumination light, etc.), and the difference is small
, There is disturbance light that greatly affects the calculation operation
I can't say that. Therefore, for example, as the reference value,
When adopting the margin voltage, the reference value (margin
Voltage), the light scanning type touch panel
Judgment that the environment is such that ambient light cannot be used
On the other hand, the difference is smaller than the reference value (margin voltage).
In the event of a disturbance, you can use the optical scanning touch panel
Judge that the environment is light. Therefore, the difference and the reference value
By outputting the comparison result with (margin voltage),
Whether or not the optical scanning touch panel is usable
It can be easily determined. Next, the cutoff range determined in this way is
Of the center position (pointing position) of the pointing object S (finger in this example)
A process for obtaining coordinates will be described. First, triangulation
The conversion from the angle based on the coordinates to the rectangular coordinates will be described. As shown in FIG.
As shown in FIG.
Set the right and upper sides of the surface 10 to the X and Y axes, and set the length of the reference line.
The distance (the distance between the light transmitting and receiving units 1a and 1b) is L.
Further, the position of the light transmitting / receiving unit 1b is assumed to be B. Display screen
The center point P (Px, Py) indicated by the indicator S on 10
Are θ and φ with respect to the X axis from the light transmitting / receiving units 1a and 1b.
, The X coordinate P of the point P
The values of the x and Y coordinates Py are calculated according to the principle of triangulation.
Can be obtained as in the following equations (1) and (2).
You. Px = (tan φ) ÷ (tan θ + tan φ) × L (1) Py = (tan θ · tan φ) ÷ (tan θ + tan φ) × L (2) By the way, the indicator S (finger) has a size. There
Therefore, the rise / fall of the detected light reception signal
FIG. 10 shows the case where the detection angle at the timing is adopted.
As described above, the four points (P in FIG. 10) at the edge of the pointer S (finger)
1 to P4). Any of these four points
Also differs from the designated center point (Pc in FIG. 10).
Therefore, the coordinates of the center point Pc (Pc
x, Pcy). Px = Px (θ, φ), Py =
If Py (θ, φ), Pcx and Pcy are
They can be expressed as the following equations (3) and (4), respectively. Pcx = Pcx (θ1 + dθ / 2, φ1 + dφ / 2) (3) Pcy = Pcy (θ1 + dθ / 2, φ1 + dφ / 2) (4) Θ1
+ Dθ / 2, φ1 + dφ / 2 are calculated by the above equations (1) and (2).
By substituting as θ and φ, the designated center point P
The coordinates of c can be obtained. In the example described above, first, the average of the angles is calculated.
Calculate the value and calculate the average value of the angle using the conversion formula for triangulation.
Substituting into (1) and (2), the center point Pc which is the designated position
The coordinates of the triangulation were calculated first.
According to (1) and (2), four points P1 to P4
Calculate the rectangular coordinates, calculate the average of the four coordinate values
It is also possible to obtain the coordinates of the center point Pc.
is there. Consider parallax and the visibility of the indicated position.
It is also possible to determine the coordinates of the center point Pc which is the designated position.
It is possible. By the way, as described above, the polygon mirror
−16a, 16b, the rotational angular velocities are constant.
By measuring the time, the information of the scanning angle can be obtained.
You. FIG. 11 shows a light receiving signal from the light receiving signal detecting circuit 3a.
And the scanning angle θ and the scanning time T of the polygon mirror 16a.
6 is a timing chart showing the relationship between the two. Polygon
When the scanning angular velocity of the mirror 16a is constant, its scanning angle
Assuming that the speed is ω, the scanning angle θ and the scanning time T
The proportional relationship shown in the expression (5) holds. θ = ω × T (5) Therefore, the falling and rising of the received light signal
The angles θ1 and θ2 at the time of scanning correspond to the respective scanning times t1 and t2.
2 and the following equations (6) and (7) hold. θ1 = ω × t1 (6) θ2 = ω × t2 (7) Accordingly, the polygon mirrors 16a and 16b
If the scanning angular velocity is constant, using the time information,
Measuring the cutoff range and coordinate position of the pointer S (finger)
Is possible. Also, the optical scanning type touch panel of the present invention
Is the size of the pointer S (finger) from the
Plane length) can also be obtained. FIG. 12 shows this cross section.
It is a schematic diagram which shows the principle of length measurement. In FIG. 12, D
1 and D2 are viewed from the light transmitting and receiving units 1a and 1b, respectively.
The section length of the pointer S. First, the optical transmitting / receiving unit 1a,
From position O (0,0), B (L, 0) of position 1b, pointer S
Distance OPc (r) to the center point Pc (Pcx, Pcy)
1), BPc (r2) is expressed by the following equations (8) and (9).
Desired. OPc = r1 = (Pcx ^Two + Pcy ^Two ) ^1/2 ... (8) BPc = r2 = ｛(L-Pcx) ^Two + Pcy ^Two ｝ ^1/2 (9) The section length is the product of the distance and the sine value of the cutoff angle.
Since it can be approximated, the cross-sectional lengths D1 and D2 are given by the following (1)
It can be measured according to equations (0) and (11). D1 = r1 · sind θ = (Pcx ^Two + Pcy ^Two ) ^1/2 · Sin θ ··· (10) D2 = r2 · sin φ = ｛(L-Pcx) ^Two + Pcy ^Two ｝ ^1/2 · Sin φ ... (11) When θ, φ ≒ 0, sin
dθ ≒ dθ ≒ tan θ, sinφ ≒ dφ ≒ tand
Since it can be approximated to φ, s in equations (10) and (11)
Instead of indθ and sinφ, dθ or tan
θ, dφ or tanφ may be used. Next, the light emission of the light emitting elements 11a and 11b is turned off.
The operation of the on / off control will be described. Optical scanning of the present invention
Type touch panel, when optical scanning stops, or
When the light scanning speed is low, the light emitting elements 11a and 11b
Stop the light emission operation and operate the
To avoid harm to the body of the data. Light scanning type touch panel at power-on
When the motor is started, the pump rotated by the pulse motor 21
The rotation speed of the rigon mirrors 16a and 16b reaches the steady rotation speed
It takes a certain amount of time to do so. Therefore, the operator
The polygon mirrors 16a and 16b are fixed in consideration of safety.
After reaching the normal rotation speed, the light emitting elements 11a and 11b are turned on.
And Thereafter, the scan opening obtained by the second timer 39a is opened.
Optical scanning speed based on the measurement result of the start timing interval
Is monitored by the MPU 5. And the light scanning speed is
When the speed becomes lower than the speed, specifically, the second timer
The measurement result obtained in 39a became larger than the predetermined value
In this case, the off signal is supplied to the light emitting element driving circuits 2a and 2b by M
The light is output from the PU 5 and the light emission operation of the light emitting elements 11a and 11b.
Stop the operation. Therefore, the scanning speed of the laser light is slow.
The laser beam is continuously radiated to the operator.
And secure the safety of the operator. However, when manufacturing an optical scanning type touch panel, etc.
Since the optical system needs to be adjusted, the pulse motor 21
Are stopped and the light-emitting elements 11a and 11
b needs to emit light. Therefore, the optical scanning type of the present invention
In the touch panel, the operation mode (scan speed
Function to turn off the laser beam when the temperature is slow)
There is a switch that can be selected. Of this switch
When the scanning speed is lower than the predetermined speed due to the switching operation
The operation mode to turn off the laser light and the scanning speed are slow
Operation mode that does not turn off the laser light, depending on the situation.
It is possible to use properly. As described above, the light scanning type touch of the present invention is
The panel turns off the scanning light for a predetermined time and
Activate the inspection unit and measure the maximum
Find the difference between the value and the minimum value, and compare the difference to a predetermined reference value.
So that the degree of the influence of disturbance light can be detected.
Thus, an erroneous detection operation can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a basic configuration of an optical scanning type touch panel of the present invention. FIG. 2 is a schematic diagram showing an internal configuration and an optical path of an optical transmission / reception unit. FIG. 3 is a block diagram of an optical scanning type touch panel of the present invention. FIG. 4 is a block diagram illustrating a configuration example of a light reception signal detection circuit. FIG. 5 is a schematic view showing an embodiment of the optical scanning type touch panel of the present invention. FIG. 6 is a waveform diagram showing a waveform of a light receiving signal when no indicator is present and a waveform of a comparison output signal thereof. FIG. 7 is a waveform diagram showing a waveform of a light receiving signal and a waveform of a comparison output signal when an indicator is present. FIG. 8 is a timing chart showing a level change of a light receiving signal. FIG. 9 is a schematic diagram showing the principle of triangulation for coordinate detection. FIG. 10 is a schematic diagram showing an indicator and a cutoff range. FIG. 11 is a timing chart showing a relationship between a light receiving signal, a scanning angle, and a scanning time. FIG. 12 is a schematic diagram showing the principle of measuring the cross-sectional length. [Description of Signs] 1a, 1b Light transmitting / receiving units 2a, 2b Light emitting element driving circuits 3a, 3b Light receiving signal detecting circuit 5 MPU 7 Retroreflective sheet 10 Display screen (coordinate plane) 11a, 11b Light emitting elements 13a, 13b Light receiving element 16a , 16b Polygon mirror 25 ROM 26 RAM 27 Timer 33a (33b), 38a (38b) Comparator 34a (34b) First timer 39a (39b) Second timer

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G06F 3/03 380 G06F 3/03 380A (72) Inventor Nobuyasu Yamaguchi 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. Fujitsu Limited (72) Inventor Yasuhide Iwamoto 4-1-1, Kamidadanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture F-term within Fujitsu Limited (reference) 2F065 AA03 DD11 FF02 FF09 FF31 HH14 JJ05 LL15 LL16 LL62 MM16 MM26 QQ25 QQ29 QQ33 2H045 BA12 BA22 BA32 CA82 DA11 DA31 5B068 AA04 BB18 DE00 5B087 AA02 AC09 BC06 CC02 CC03 CC05 CC09 CC34

Claims (1)

Claims: 1. An optical scanning section for angularly scanning light in a plane substantially parallel to a predetermined area, a light receiving element for receiving a part of the scanning light, and an instruction for the predetermined area. Means for turning off the scanning light, and measuring a predetermined time in an optical scanning type touch panel including a measuring unit for measuring a blocking position of the scanning light formed by an object based on an output of the light receiving element corresponding to a scanning angle. A timer, and arithmetic means for calculating a difference between a maximum value and a minimum value of a light receiving result at the light receiving element when the scanning light is turned off and the light scanning unit is operated by turning off the scanning light for the predetermined time. A light scanning type touch panel comprising: a comparison unit that compares the difference calculated by the calculation unit with a predetermined reference value.