JP4111617B2 - Optical scanning touch panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical scanning touch panel that optically detects the position of an indicator on a display screen.
[0002]
[Prior art]
With the spread of computer systems such as personal computers mainly, new information can be input by instructing on the display screen of a display device on which information is displayed by the computer system with a human finger or a specific indicator, Devices that give various instructions to a computer system are used.
[0003]
When an input operation is performed on the information displayed on the display screen of a display device such as a personal computer by a touch method, it is necessary to detect the contact position (indicated position) on the display screen with high accuracy. . As an example of a method for detecting the indicated position on the display screen as such a coordinate plane, an optical position detection method is proposed in Japanese Patent Application Laid-Open No. 62-5428. In this method, optical retroreflectors are arranged on both side frames of the display screen, the return light from the optical retroreflector of the angle-scanned laser beam is detected, and from the timing when the light beam is blocked by a finger or a pen. The presence angle of the finger or pen is obtained, and the position coordinates are detected from the obtained angle by the principle of triangulation. In this method, the number of parts is small and detection accuracy can be maintained, and the position of a finger, an arbitrary pen, or the like can be detected.
[0004]
Such an optical scanning touch panel that detects a position by using scanning light generally includes a retroreflector provided outside the display screen, a light emitting element that emits light such as laser light, and an angle of the emitted light. And two sets of optical units including light scanning means such as a polygon mirror for scanning, and a light receiving element for receiving the reflected light of the scanned light by a retroreflector. In each optical unit, light from the light emitting element is provided. Is scanned by the optical scanning means, and the light reflected by the retroreflector of the scanned light is reflected by the optical scanning means and received by the light receiving element. When an indicator such as a finger or an arbitrary pen exists in the scanning light path, the light reflected by the retroreflector is not received by the light receiving element. Therefore, based on the scanning angle of the optical scanning means in each optical unit and the light reception result of the light receiving element, the position of the indicator can be detected.
[0005]
[Problems to be solved by the invention]
In such an optical scanning touch panel, in one optical scanning, an interrupt signal is generated according to the end of scanning or confirmation of light shielding by an indicator, and a light receiving signal (from a retroreflector) detected by the light receiving element is detected. (Reflected light) is being read. Further, the start of scanning in one optical scanning is determined according to a reference signal that is directly input to the light receiving element after the light from the light emitting element is reflected by the optical scanning means in the optical unit. Such optical scanning control is independently performed in each optical unit, the timing of each reference signal is not matched, and the detection intervals do not match due to different optical scanning periods in each optical unit.
[0006]
Therefore, even if it is intended to realize highly accurate detection in the conventional optical scanning touch panel, the simultaneous detection of both optical units is not maintained, and a delay of one optical scanning at the maximum is caused by the difference in the optical scanning period. There is a problem that a time delay of position detection occurs.
[0007]
Further, the reference signal as described above does not correspond to the actual scanning angle of 0 ° (true scanning start reference line), and the scanning angle information detected based on the reference signal is matched with the design specifications of the optical unit. Therefore, there is a problem that it is necessary to correct the angle and to incorporate software for the correction.
[0008]
The present invention has been made in view of such circumstances, and can synchronize the start of optical scanning in a plurality of optical units, and can maintain the synchronization of detection in each optical unit and delay the time of position detection. An object of the present invention is to provide an optical scanning touch panel capable of minimizing the above.
[0009]
Another object of the present invention is to provide an optical scanning touch panel that eliminates the need for angle correction from the reference signal based on the design specification by receiving the scanning light of each other as a reference signal.
[0010]
[Means for Solving the Problems]
An optical scanning touch panel according to claim 1 includes an optical scanning unit that angularly scans light in a plane substantially parallel to a predetermined region, and a light receiving unit that receives scanning light from the optical scanning unit. a plurality of, in the light scanning touch panel is detected based on a light receiving output of the predetermined region on the light receiving means for the blocking position of the scanning light corresponding to a scanning angle of forming at representations, optical scanning of the previous SL plurality of optical units The optical scanning synchronizing means synchronizes the optical scanning based on the time difference when the light receiving outputs from the respective light receiving means corresponding to the reference scanning angle are respectively inputted as reference signals. and requirements that you have to.
[0011]
In the optical scanning touch panel of the present invention, the reference signals in a plurality of optical units are compared, and the timings of the reference signals are synchronized. Therefore, in each optical unit, the timing of the optical scanning start coincides and the optical scanning is performed in synchronization. As a result, there is almost no time delay in position detection.
[0013]
Also , the timing at which the scanning light is received is used as a reference signal for starting optical scanning. In this case, since the reference signal corresponds to the true scanning start reference line, the angle correction that is necessary in the case of the reference signal as in the related art becomes unnecessary.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof. FIG. 1 is a schematic diagram showing a basic configuration of an optical scanning touch panel according to the present invention.
[0015]
In FIG. 1, reference numeral 10 denotes a rectangular display screen such as a CRT or flat display panel (PDP, LCD, EL, etc.), a projection type video display device, etc. in an electronic device such as a personal computer. (Plasma display) display screen.
[0016]
For example, both corners of one short side (right side in the present embodiment) of the rectangular display screen 10 which is a range of a plane defined as a target area to be touched by an indicator S such as a finger or a pen. Optical units 1a and 1b each having an optical system including a light emitting element, a light receiving element, a polygon mirror, various lenses, and the like are provided outside. Further, a retroreflective sheet 7 as a retroreflector is provided on three sides excluding the right side of the display screen 10, that is, on the outer sides of the upper and lower sides and the left side.
[0017]
FIG. 2 is a diagram illustrating the configuration and optical paths of the optical units 1a and 1b. Both optical units 1a and 1b have the same internal configuration. The optical unit 1a (1b) includes a light emitting element 11 made of a laser diode (LD) that emits infrared laser light, a collimation lens 12 for making the laser light from the light emitting element 11 parallel light, and a retroreflective sheet 7. A light receiving element 13 composed of a photodiode (PD) that receives reflected light from the light, a slit plate 14 having a slit 14 a for limiting incident light to the light receiving element 13, and angle scanning of the laser light from the light emitting element 11. For example, the projection light from the collimation lens 12 to the polygon mirror 15 is limited by the quadrangular prism-shaped polygon mirror 15 and the aperture 16a, and the reflected light from the retroreflection sheet 7 via the polygon mirror 15 is received by the light receiving element. Aperture mirror 16 that reflects to side 13 and the light reflected by aperture mirror 16 is focused. It comprises a condenser lens 17 for a motor 18 for rotating the polygon mirror 15, an optical unit main body 19 for fixing the mounting of these optical members.
[0018]
The laser light emitted from the light emitting element 11 is collimated by the collimation lens 12, passes through the aperture 16 a of the aperture mirror 16, and then is in-plane substantially parallel to the display screen 10 by the rotation of the polygon mirror 15. Are scanned and projected onto the retroreflective sheet 7. The reflected light from the retroreflective sheet 7 is reflected by the polygon mirror 15 and the aperture mirror 16, then converged by the condenser lens 17, and incident on the light receiving element 13 through the slit 14 a of the slit plate 14. Is done. However, when the indicator S is present in the scanning light path, the projected light is blocked, and thus the reflected light does not enter the light receiving element 13.
[0019]
Each optical unit 1a, 1b includes light emitting element driving circuits 2a, 2b for driving each light emitting element 11, light receiving signal detection circuits 3a, 3b for converting the amount of light received by each light receiving element 13 into an electric signal, and each polygon mirror. A scanning synchronization control circuit 4 which is a characteristic part of the present invention is connected to control the operation of 15 to synchronize the start of optical scanning in each of the optical units 1a and 1b. Reference numeral 5 denotes an MPU that calculates the position and size of the indicator S and controls the operation of the entire apparatus. Reference numeral 5 denotes a display device that displays a calculation result of the MPU 5 and the like.
[0020]
The MPU 5 sends a drive control signal to the light emitting element driving circuits 2a and 2b, and the light emitting element driving circuits 2a and 2b are driven in accordance with the drive control signal, so that the light emitting operation of each light emitting element 11 is controlled. The light reception signal detection circuits 3 a and 3 b send the light reception signals from the respective light receiving elements 13 to the MPU 5. The MPU 5 calculates the position and size of the indicator S based on the light reception signal from each light receiving element 13 and displays the calculation result on the display device 6. The display device 6 can also serve as the display screen 10.
[0021]
In the optical scanning touch panel of the present invention, as shown in FIG. 1, for example, the optical unit 1b will be described. From the position where the projection light from the optical unit 1b is incident on the light receiving element 13, FIG. The position is scanned in the counterclockwise direction above, and reaches the position (Ps) reflected by the tip portion of the retroreflective sheet 7 to become a substantial scanning start position. And until the position (P1) reaching one end of the indicator S is reflected by the retroreflective sheet 7, it is blocked by the indicator S until the position (P2) reaching the other end of the indicator S, and thereafter Until the scanning end position (Pe) is reflected by the retroreflective sheet 7.
[0022]
In such optical scanning, the projection light from the light emitting element 11 does not reach the retroreflective sheet 7 but scans the aperture mirror 16 with the polygon mirror 15 and directly detects the detection light signal incident on the light receiving element 13. A reference signal for starting scanning is used. That is, the scanning angle is measured when such a reference signal is detected.
[0023]
Each optical unit 1a, 1b detects a reference signal by direct incidence of scanning light in this way. In each of the optical units 1a and 1b, the scanning light is configured to rotate independently at a constant period, and the phase is shifted due to subtle variations in circuit constants. Therefore, in the present invention, the phases of the reference signals in both the optical units 1a and 1b are compared, the rotational speed of the polygon mirror 15 on the optical unit 1b side is increased or decreased by PLL synchronization, and the timing (reference signal) for starting optical scanning is determined. Both optical units 1a and 1b are synchronized.
[0024]
FIG. 3 is a diagram showing an internal configuration of the scanning synchronization control circuit 4 that synchronizes both reference signals. The scan synchronization control circuit 4 includes a PLL circuit 21 and a clock generator 22. The PLL circuit 21 receives light reception signals (reference signals) from the light receiving elements 13 and 13 of both optical units 1a and 1b from the optical signal detection circuits 3a and 3b, and calculates the time difference from the number of clocks from the clock generator 22. A servo signal for adjusting the rotation timing based on the time difference is sent to the optical unit 1b. Then, the rotational speed of the polygon mirror 15 of the optical unit 1b is adjusted according to this servo signal, and the reference signals in both the optical units 1a and 1b are synchronized.
[0025]
4 (a) and 4 (b) are timing charts showing an example of synchronization control of such a reference signal. In the example of FIG. 4A, since the phase of the reference signal in the optical unit 1b is delayed from that of the reference signal in the optical unit 1a, a (+) servo signal is sent to the optical unit 1b and the polygon of the optical unit 1b is sent. Both reference signals are synchronized by increasing the rotation speed of the mirror 15. On the other hand, in the example of FIG. 4B, since the phase of the reference signal in the optical unit 1b is ahead of the phase of the reference signal in the optical unit 1a, a servo signal (−) is sent to the optical unit 1b to send the optical unit 1b. The rotation speed of the polygon mirror 15 is slowed to synchronize both reference signals.
[0026]
By the control operation in the scanning synchronization control circuit 4 as described above, the rotation period of the optical scanning in both the optical units 1a and 1b becomes constant so that the optical unit 1b is synchronized with the period of the optical unit 1a.
[0027]
Next, another embodiment of the present invention in which scanning light from one optical unit is used as a reference signal for starting optical scanning will be described. In this embodiment as well, synchronization processing is performed by PLL control as in the above-described embodiment using the direct incident light of scanning light in its own optical unit as a reference signal.
[0028]
FIG. 5A is a diagram showing a light reception signal in the light receiving element 13 in the optical unit 1a. In FIG. 5A, D _a1 is a received light signal (reference signal in the above-described embodiment) corresponding to the direct incident light from the polygon mirror 15 in the optical unit 1a, and D _a2 is a scan from the optical unit 1b. A light reception signal corresponding to light (a reference signal in the present embodiment), _Da3 represents a light reception signal corresponding to the reflected light from the retroreflective sheet 7.
[0029]
Moreover, the light reception signal in the light receiving element 13 in the optical unit 1b is shown in FIG. In FIG. 5B, as in FIG. 5A, D _b1 is a received light signal (reference signal in the above embodiment) corresponding to the direct incident light from the polygon mirror 15 in the optical unit 1b, D _b2 represents a light reception signal (reference signal in the present embodiment) corresponding to the scanning light from the optical unit 1a, and _Db3 represents a light reception signal corresponding to the reflection light from the retroreflective sheet 7.
[0030]
5A and 5B also show the rotation angle of the scanning light. The rotation angle of the scanning light is measured using a straight line connecting both optical units 1a and 1b as a scanning reference line. Therefore, the scanning angle in the light reception signals D _a2 and D _b2 is 0 °. The optical units 1a and 1b are provided in the non-scanning region, and the scanning angles in the light reception signals D _a1 and D _b1 are −α _a and −α _b . Specifically, α _a = α _b = about 6 °. The scanning angle in the light reception signals D _a3 and D _{b3 is} between β _a and β _b corresponding to Ps in FIG. 1 to 90 ° corresponding to Pe in FIG. Specifically, β _a = β _b = about 3 °.
[0031]
When the direct incident light (the received light signals D _a1 and D _b1 ) in each of the optical units 1a and 1b is used as a reference signal, the scanning angle is measured from a position shifted by α _a and α _b from the scanning reference line. The measurement value as it is cannot be used for the position detection process of the indicator S, and it is necessary to calculate the position detection of the indicator S after correcting the measurement value by the shift angles α _a and α _b . Further, since α _a and α _b also change according to the mounting specifications of the optical units 1a and 1b, complicated calibration with the display position for eliminating the mounting error is also necessary.
[0032]
On the other hand, in this embodiment, since the scanning light (light reception signals D _a2 and D _b2 ) from the opposing optical unit is used as a reference signal, the scanning angle is measured from the scanning reference line, which is described above. Without performing such angle correction, the measured value can be used as it is in the calculation of the position detection of the indicator S. Therefore, the configuration can be simplified and the design angle adjustment at the time of assembling the optical unit is not necessary. In addition, calibration with the display position can be simplified.
[0033]
By the way, in this Embodiment, it is necessary for scanning light to reach | attain the other optical unit 1b (1a) from one optical unit 1a (1b), and other members are put in the linear space of both optical units 1a and 1b. There may be a restriction that it cannot be provided. And it is common to provide the fixing member for fixing the display screen 10 in this linear space, and there exists a subject that this Embodiment cannot be implement | achieved.
[0034]
FIG. 6 is a schematic diagram showing an embodiment in which such a problem is solved. A fixing member 30 for fixing the display screen 10 is provided in the linear space of both the optical units 1a and 1b, but the scanning light is guided between the optical units 1a and 1b while avoiding the installation position of the fixing member 30. A prism light guide 31 is installed. FIG. 7 shows a configuration example of the prism light guide 31 and an internal optical path.
[0035]
Since the prism light guide 31 is provided so that the scanning light can be guided between the optical units 1a and 1b, the linear space is not essential, and the installation restriction of the fixing member 30 for fixing the display screen 10 is restricted. Relaxation can be achieved.
[0036]
Next, the optical scanning period in both optical units 1a and 1b is made constant (the optical scanning start timing is synchronized), and the scanning angle in both optical units 1a and 1b is also made constant. Will be described.
[0037]
FIG. 8 is a control block diagram in this embodiment. In FIG. 8, the same reference numerals as those in FIGS. 1 to 3 denote the same members. Each optical unit 1a, 1b is provided with a PLL circuit 41 that adjusts the phase shift of the rotation of the polygon mirror 15 and a clock generator 42 that generates a reference clock. The optical unit 1b is further provided with an adder 43 that adds the servo signal from the PLL circuit 41 and the servo signal from the PLL circuit 21.
[0038]
In the optical unit 1a, the rotation signal of the motor 18 for the polygon mirror 15 is input to the PLL circuit 41, and the difference from the reference rotation is obtained by converting into the number of clocks from the clock generator 42, and based on the difference. A servo signal for adjusting the rotation speed is fed back to the motor 18.
[0039]
In the optical unit 1b, the rotation signal of the motor 18 is input to the PLL circuit 41, and the difference from the reference rotation is obtained by conversion into the number of clocks from the clock generator 42, and the rotation speed is adjusted based on the difference. A servo signal is sent to the adder 43. A reference signal from the optical units 1a and 1b is input to the PLL circuit 21, and the time difference is obtained by converting the number of clocks from the clock generator 22, and a servo for adjusting the rotation speed based on the time difference. The signal is sent to the adder 43. These servo signals are added by an adder 43 and the added signal is fed back to the motor 18.
[0040]
By the control operation as described above, not only the optical scanning period of both optical units 1a and 1b can be made constant, but also the optical scanning angle can be made constant.
[0041]
Next, the calculation operation of the position and size of the pointing object S by the optical scanning touch panel of the present invention will be described. FIG. 9 is a schematic diagram showing an implementation state of the optical scanning touch panel. However, in FIG. 9, components other than the optical units 1a and 1b, the retroreflective sheet 7, and the display screen 10 are not shown. Moreover, the case where a finger is used as the pointing object S is shown.
[0042]
The polygon mirrors 15 in the optical units 1a and 1b are rotated so that the laser beams from the light emitting elements 11 are angularly scanned. As a result, the reflected light from the retroreflective sheet 7 enters each light receiving element 13. In this way, the amount of received light incident on each light receiving element 13 is obtained as a light receiving signal that is an output of the light receiving signal detection circuits 3a and 3b.
[0043]
In FIG. 9, θ00 and φ00 are angles from the reference line connecting both optical units 1a and 1b to the respective light receiving elements (corresponding to α _a and α _b in FIGS. 5A and 5B), θ0, φ0 is the angle from the reference line connecting the optical units 1a and 1b to the end of the retroreflective sheet 7 (corresponding to β _a and β _b in FIGS. _5A and _5B ), and θ1 and φ1 are the reference The angle from the line to the reference line side end of the indicator S, and θ2 and φ2 denote the angle from the reference line to the reference line and the opposite side end of the indicator S, respectively.
[0044]
When the indicator S exists in the optical path of the scanning light on the display screen 10, the reflected light from the indicator S of the light projected from the optical units 1 a and 1 b is not incident on each light receiving element 13. Therefore, in the state as shown in FIG. 9, when the scanning angle is from 0 ° to θ0, no reflected light is incident on the light receiving element 13 in the optical unit 1a, and the scanning angle is from θ0 to θ1. In the interval, the reflected light is incident on the light receiving element 13, and the reflected light is not incident on the light receiving element 13 when the scanning angle is between θ1 and θ2. Similarly, no reflected light is incident on the light receiving element 13 in the optical unit 1b when the scanning angle is from 0 ° to φ0, and reflected light is incident on the light receiving element 13 when the scanning angle is from φ0 to φ1. When the scanning angle is between φ1 and φ2, no reflected light is incident on the light receiving element 13.
[0045]
Next, processing for obtaining the coordinates of the center position (designated position) of the pointing object S (finger in this example) from the cut-off range obtained in this way will be described. First, the conversion from an angle based on triangulation to Cartesian coordinates will be described. As shown in FIG. 10, the position of the optical unit 1a is set to the origin O, the right side and the upper side of the display screen 10 are set to the X axis and the Y axis, and the length of the reference line (distance between the optical units 1a and 1b) is set to L. And The position of the optical unit 1b is assumed to be B. When the center point P (Px, Py) indicated by the indicator S on the display screen 10 is located at angles of θ and φ with respect to the X axis from the optical units 1a and 1b, respectively, the X coordinate of the point P The values of the Px and Y coordinates Py can be obtained by the following formulas (1) and (2), respectively, based on the principle of triangulation.
Px (θ, φ) = (tanφ) ÷ (tanθ + tanφ) × L (1)
Py (θ, φ) = (tan θ · tan φ) ÷ (tan θ + tan φ) × L (2)
[0046]
By the way, since the indicator S (finger) has a size, when the detection angle at the rising / falling timing of the detected light receiving signal is adopted, as shown in FIG. Four points (P1 to P4 in FIG. 11) of the edge portion are detected. These four points are all different from the designated center point (Pc in FIG. 11). Therefore, the coordinates (Pcx, Pcy) of the center point Pc are obtained as follows. Pcx and Pcy can be expressed by the following equations (3) and (4), respectively.
Pcx (θ, φ) = Pcx (θ1 + dθ / 2, φ1 + dφ / 2) (3)
Pcy (θ, φ) = Pcy (θ1 + dθ / 2, φ1 + dφ / 2) (4)
[0047]
Therefore, by substituting θ1 + dθ / 2 and φ1 + dφ / 2 represented by the equations (3) and (4) as θ and φ in the above equations (1) and (2), the coordinates of the instructed center point Pc are obtained. Can be sought.
[0048]
In the above-described example, the average value of the angle is first obtained, and the average value of the angle is substituted into the triangulation conversion formulas (1) and (2) to obtain the coordinates of the center point Pc that is the designated position. First, the orthogonal coordinates of the four points P1 to P4 are obtained from the scanning angle according to the triangulation conversion formulas (1) and (2), the average of the obtained coordinate values of the four points is calculated, and the center point It is also possible to obtain the coordinates of Pc. Further, it is possible to determine the coordinates of the center point Pc that is the designated position in consideration of the parallax and the visibility of the designated position.
[0049]
By the way, when the rotational angular velocity of each polygon mirror 15 is constant, information on the scanning angle can be obtained by measuring time. FIG. 12 is a timing chart showing the relationship between the light reception signal from the light reception signal detection circuit 3a and the scanning angle θ and scanning time T of the polygon mirror 15 in the optical unit 1a. When the scanning angular velocity of the polygon mirror 15 is constant, assuming that the scanning angular velocity is ω, the scanning angle θ and the scanning time T have a proportional relationship as shown in the following equation (5).
θ = ω × T (5)
[0050]
Therefore, the angles θ1 and θ2 at the time of falling and rising of the received light signal have the relationship between the scanning times t1 and t2 and the following expressions (6) and (7).
θ1 = ω × t1 (6)
θ2 = ω × t2 (7)
[0051]
Therefore, when the scanning angular velocity of the polygon mirror 15 is constant, it is possible to measure the blocking range and coordinate position of the indicator S (finger) using time information.
[0052]
In the optical scanning touch panel of the present invention, the size (cross-sectional length) of the indicator S (finger) can be obtained from the measured blocking range. FIG. 13 is a schematic diagram showing the principle of the cross-sectional length measurement. In FIG. 13, D1 and D2 are the cross-sectional lengths of the indicator S viewed from the optical units 1a and 1b, respectively. First, distances OPc (r1) and BPc (r2) from the positions O (0, 0) and B (L, 0) of the optical units 1a and 1b to the center point Pc (Pcx, Pcy) of the indicator S are as follows. It is obtained as shown in equations (8) and (9).
OPc = r1 = (Pcx ² + Pcy ² ) ^1/2 (8)
BPc = r2 = {(L-Pcx) ² + Pcy ² } ^1/2 (9)
[0053]
Since the cross-sectional length can be approximated by the product of the distance and the sine value of the cutoff angle, the cross-sectional lengths D1 and D2 can be measured according to the following equations (10) and (11).
D1 = r1 · 2sindθ / 2
= (Pcx ² + Pcy ² ) ^1/2 · 2 sin θ / 2 (10)
D2 = r2 · 2sindφ / 2
= {(L-Pcx) ² + Pcy ² } ^1/2 · 2 sin φ / 2
... (11)
[0054]
In the case of θ, φ≈0, it can be approximated as sinθ≈dθ≈tandθ, sindφ≈dφ≈tandφ. Therefore, in the equations (10) and (11), dθ or tandθ, dφ instead of sindθ and sindφ. Alternatively, tandφ may be used.
[0055]
【The invention's effect】
In the optical scanning touch panel of the present invention, the reference signals in the plurality of optical units are compared and the timings of the reference signals are synchronized, so that the optical scanning start timings coincide and the optical scanning can be performed synchronously. It is possible to minimize the time delay of the position detection.
[0056]
Further, in the optical scanning touch panel of the present invention, since the mutual scanning light is received and used as the reference signal, the angle correction from the reference signal based on the design specification is unnecessary, and the configuration can be simplified. is there.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a basic configuration of an optical scanning touch panel of the present invention.
FIG. 2 is a diagram illustrating a configuration and an optical path of an optical unit.
FIG. 3 is a diagram showing an internal configuration of a scanning synchronization control circuit.
FIG. 4 is a timing chart illustrating an example of reference signal synchronization control;
FIG. 5 is a diagram showing a light reception signal in a light receiving element.
FIG. 6 is a schematic view showing a main part of the optical scanning touch panel of the present invention.
FIG. 7 is a diagram illustrating a configuration example of a prism light guide and an internal optical path.
FIG. 8 is a control block diagram of the optical scanning touch panel of the present invention.
FIG. 9 is a schematic diagram showing an implementation state of the optical scanning touch panel.
FIG. 10 is a schematic diagram showing the principle of triangulation for coordinate detection.
FIG. 11 is a schematic diagram showing an indicator and a blocking range.
FIG. 12 is a timing chart showing a relationship among a light reception signal, a scanning angle, and a scanning time.
FIG. 13 is a schematic diagram showing the principle of cross-sectional length measurement.
[Explanation of symbols]
1a, 1b Optical unit 4 Scanning synchronization control circuit 5 MPU
7 Retroreflective sheet 10 Display screen (coordinate plane)
11 Light Emitting Element 13 Light Receiving Element 15 Polygon Mirror 18 Motor 21 PLL Circuit S Indicator

Claims (1)

A plurality of optical units each having an optical scanning means for angularly scanning light in a plane substantially parallel to the predetermined area, and a light receiving means for receiving scanning light from the optical scanning means; In the optical scanning type touch panel for detecting the blocking position of the scanning light to be formed based on the light receiving output of the light receiving means corresponding to the scanning angle ,
Includes the optical scanning synchronization means for synchronizing the optical scanning before Symbol plurality of optical units,
The optical scanning synchronization means synchronizes the optical scanning based on the time difference when the light receiving outputs from the respective light receiving means corresponding to the reference scanning angle are respectively inputted as reference signals. Type touch panel.

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