JP4175715B2 - 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, a light retroreflector is disposed on both sides of the display screen, the return light of the angle-scanned laser beam is detected from the light retroreflector, and the light is blocked by a finger or a pen. Then, the presence angle of the finger or the pen is obtained from the position, 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 the emitted light. An optical scanning means such as a polygon mirror for angle scanning, a deflection element for deflecting reflected light of the scanning light by a retroreflector, and a light receiving element for receiving the deflected reflected light are provided. The optical scanning means scans the light, the reflected light from the retroreflector of the scanning light is reflected again by the optical scanning means, and the reflected light is received by the light receiving element via the deflecting element. Yes. 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, the positions of these indicators can be detected based on the scanning angle of the optical scanning means and the light reception result of the light receiving element.
[0005]
[Problems to be solved by the invention]
In the optical scanning touch panel, light that is directly incident on the light receiving element after the scanning light from the optical scanning unit scans the width of the deflecting element is used as a reference signal for one optical scanning. Further, the scanning light reaches one edge of the retroreflector, and the reflected light is received by the light receiving element to obtain a scanning start signal.
[0006]
When optical scanning is performed, the reference signal and the scanning start signal are very close to each other in terms of scanning time, and the reference signal affects the scanning start signal, which makes it difficult to distinguish both signals. . Therefore, conventionally, for example, the incident angle of the scanning light to the optical scanning means is separated by an angle corresponding to three times or more the beam size of the scanning light in mounting, thereby mitigating the influence. Such a technique restricts the degree of design freedom in mounting, and is a factor that hinders the realization of a compact configuration. In addition, it is necessary to set a specific slice level in order to separate the reference signal and the scanning start signal, and there is a problem that the circuit configuration becomes complicated.
[0007]
The present invention has been made in view of such circumstances, and an object thereof is to provide an optical scanning touch panel that can easily distinguish a reference signal and a scanning start signal with a simple configuration.
[0008]
[Means for Solving the Problems]
An optical scanning touch panel according to the present invention includes a light emitting means for emitting light, an optical scanning means for angularly scanning the light in a plane substantially parallel to a predetermined area, and scanning light from the optical scanning means. A light receiving means for receiving light, wherein the light emitting means detects the blocking position of the scanning light formed by the indicator in the predetermined area based on the light receiving output of the light receiving means corresponding to a scanning angle. be between the light scanning means and, in a region that does not interfere with the light path of the emitted from the light emitting means, in order to block the diffused light as a noise light not be the scanning light, the light irradiation Comprising a flat quadrangular prism-shaped light shielding means arranged along the longitudinal direction of the parallel light path from the light means to the optical scanning means, and a non-reflective treatment is applied to a portion on the optical path side of the light shielding means. And
[0009]
The reason why it is difficult to distinguish between the reference signal and the scanning start signal is that the reflected light, diffracted light, etc. from various members of the optical scanning touch panel are irradiated and reflected as noise light on the optical scanning means. It is considered that the reference signal has a shape in which the base is widened by being added to the scanning light, and the boundary with the subsequent scanning start signal becomes unclear. Therefore, in the present invention, the light shielding means is provided in a region not involved in the normal irradiation light path from the light emitting means to the light scanning means so that such noise light does not reach the light scanning means. By this light shielding means, noise light is blocked and does not reach the optical scanning means, but only regular scanning light is incident on the light receiving means, the falling edge of the reference signal becomes sharp, and the boundary with the scanning start signal is clear Thus, the reference signal and the scan start signal can be easily distinguished.
[0011]
Further, a non-reflective treatment is applied to the surface of the light shielding means on the side of the optical scanning means. Therefore, even when such noise light reaches the optical scanning means and is reflected, the non-reflective treatment is applied to the surface of the light shielding means on the optical scanning means side, so that the reflected light is incident on the light receiving means. Only the regular scanning light is incident on the light receiving means, the falling edge of the reference signal becomes sharp, the boundary with the scanning start signal becomes clear, and the reference signal and the scanning start signal can be easily discriminated. Yes.
[0012]
An optical scanning touch panel according to the present invention includes an optical scanning unit that scans an angle of light in a plane substantially parallel to a predetermined region, and a light receiving unit that receives scanning light from the optical scanning unit. In an optical scanning touch panel for detecting a blocking position of scanning light formed by an indicator in an area based on a light receiving output of the light receiving means corresponding to a scanning angle, between the light scanning means and the light receiving means, In order to block the diffused light as noise light that does not become scanning light in a region that does not obstruct the scanning light path by the optical scanning means, it is along the parallel light path from the optical scanning means to the light receiving means. In this case, the light shielding means is a flat quadrangular prism and is disposed on the optical path side of the light shielding means.
[0013]
In order to eliminate the influence of noise light on the light receiving means, a light shielding means is provided in a region on the scanning light incident side of the light receiving means that is not involved in the scanning light path. With this light blocking means, noise light does not reach the light receiving means, but only regular scanning light is incident on the light receiving means, the falling edge of the reference signal becomes sharp, the boundary with the scanning start signal becomes clear, and the reference signal And the scanning start signal can be easily distinguished.
[0016]
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.
[0017]
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.
[0018]
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.
[0019]
(First embodiment)
FIG. 2 is a diagram showing the configuration and optical path of the optical units 1a and 1b in the first embodiment. 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) for receiving reflected light from the light source, a polygonal prism 14 having a quadrangular prism shape for scanning the laser light from the light emitting element 11, and a polygon from the collimation lens 12 by an aperture 15a. The projection light to the mirror 14 is limited, the aperture mirror 15 that reflects the reflected light from the retroreflective sheet 7 through the polygon mirror 14 toward the light receiving element 13, and the reflected light from the aperture mirror 15 is received by the light receiving element 13. A condensing lens 16 for focusing the light and a motor 1 for rotating the polygon mirror 14 A light shielding member 18 that is provided on the side opposite to the scanning region with respect to the optical path between the aperture mirror 15 and the polygon mirror 14, and prevents the polygon mirror 14 from being irradiated with noise light, and these optical members. And an optical unit main body 19 for mounting and fixing. The condensing lens 16 is fixed in a cylindrical lens holder 20 fitted in the hollow portion of the optical unit body 18.
[0020]
The laser light emitted from the light emitting element 11 is collimated by the collimation lens 12, passes through the aperture 15 a of the aperture mirror 15, and then rotates within the plane substantially parallel to the display screen 10 by the rotation of the polygon mirror 14. Are scanned and projected onto the retroreflective sheet 7. Then, the reflected light from the retroreflective sheet 7 is reflected by the polygon mirror 14 and the aperture mirror 15, then converged by the condenser lens 17 and incident on the light receiving element 13. However, since the scanning light is blocked when the indicator S is present in the scanning light path, the reflected light does not enter the light receiving element 13.
[0021]
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. 14 is connected to a polygon control circuit 4 for controlling the operation of 14. 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.
[0022]
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 of the reflected light 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.
[0023]
In the optical scanning touch panel of the present invention, as shown in FIG. 1, for example, the optical unit 1 b will be described. The projection light from the optical unit 1 b is reflected by the aperture mirror 15. Scanning in the counterclockwise direction in FIG. 1 from the position directly incident on the light receiving element 13 reaches the position (Ps) reflected by the tip portion of the retroreflective sheet 7 and becomes the 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.
[0024]
In such an optical scanning, the projection light from the light emitting element 11 does not reach the retroreflective sheet 7 but scans the aperture mirror 15 with the polygon mirror 14 and directly detects the detection light signal incident on the light receiving element 13. Use as a reference signal. Further, the detection light signal reflected when the scanning light reaches the tip portion (Ps in FIG. 1) of the retroreflective sheet 7 becomes a scanning start signal, and then the reflected light from the retroreflective sheet 7 is received by the light receiving element 13. And a retroreflected signal is obtained. The scanning angle is measured from the time when this reference signal is detected.
[0025]
Next, the operation of the light shielding member 18 which is a characteristic part of the first embodiment will be described. 3A and 3B are diagrams showing a conventional example in which such a light shielding member does not exist. FIG. 3A is a schematic diagram of the configuration and the optical path of the conventional example, and FIG. 3B is a diagram illustrating the polygon mirror 14 in the conventional example. The figure which shows the beam shape of irradiation light, FIG.3 (c) is a figure which shows the reference signal and retroreflection signal in a prior art example. In FIG. 3A, the same parts as those in FIG.
[0026]
In the conventional example in which no light shielding member is present, diffused light as noise light that does not become scanning light is applied to the polygon mirror 14 as shown by a broken line in FIG. 3A and A in FIG. Light enters the light receiving element 13. As a result, the edge of the reference signal B shown in FIG. 3C is not sharp and the boundary with the subsequent retroreflection signal C becomes unclear, so that the reference signal B and the retroreflection signal C are accurately detected. Cannot be determined.
[0027]
On the other hand, FIG. 4 is a diagram showing the first embodiment in which the light shielding member 18 is present. FIG. 4A is a schematic diagram of the configuration and optical path of the first embodiment, and FIG. The figure which shows the beam shape of the irradiation light to the polygon mirror 14 in embodiment, FIG.4 (c) is a figure which shows the reference | standard signal and retroreflection signal in 1st Embodiment. As shown in FIG. 4A, the light shielding member 18 includes a flat rectangular columnar support member 18a along the longitudinal direction of a parallel light path from the aperture 15a toward the polygon mirror 14, and an optical path of the support member 18a. The non-reflective tape 18b is affixed to the surface on the side, and is disposed in an area on the opposite side of the scanning area with respect to the optical path so as not to obstruct the optical path.
[0028]
In the first embodiment, since such a light shielding member 18 exists, diffused light that becomes noise light is absorbed or scattered on the surface of the light shielding member 18 and is not irradiated onto the polygon mirror 14. Therefore, as shown in FIG. 4B, the diffused light component (component A as shown in FIG. 3B) on the side opposite to the scanning region disappears in the beam shape of the irradiation light to the polygon mirror 14, As a result, the edge of the reference signal B shown in FIG. 4C is sharp, the boundary with the subsequent retroreflection signal C is clear, and the reference signal B and the retroreflection signal C are accurately discriminated. it can.
[0029]
As described above, in the first embodiment, the light blocking member 18 is provided, and noise light that becomes diffuse light such as internally reflected light from the optical member such as the aperture mirror 15 and diffracted light from the aperture 15a is incident on the scanning optical system. Therefore, the reference signal and the retroreflective signal (scanning start signal) can be easily and accurately distinguished.
[0030]
(Second Embodiment)
FIG. 5 is a diagram showing the configuration and optical paths of the optical units 1a and 1b in the second embodiment. In FIG. 5, the same parts as those in FIG.
[0031]
In the second embodiment, the light shielding member 18 is erected on the optical unit main body 19 in the vicinity of the circumscribed circle of the polygon mirror 14 so that the longitudinal direction thereof is aligned with the axial direction of the polygon mirror 14. Other configurations, optical scanning operations, reference signal detection, and the like are the same as those in the first embodiment.
[0032]
The characteristics of the light shielding member 18 in the second embodiment will be described in detail. FIG. 6 is a schematic diagram of the configuration and optical path of an example of the second embodiment, and FIG. 7 is a schematic diagram of the configuration and optical path of another example of the second embodiment.
[0033]
In the configuration example shown in FIG. 6, the light shielding member 18 having a configuration in which the non-reflective tape 18 b is attached to the surface of the flat rectangular columnar support member 18 a on the aperture 15 a side is in the vicinity of the circumscribed circle of the polygon mirror 14. It is provided on the side opposite to the scanning region with respect to the path of the parallel light from 15a so as not to obstruct the optical path. In this example, since such a light shielding member 18 exists, the diffused light that becomes noise light indicated by the broken line in FIG. 6 is absorbed or scattered by the surface of the light shielding member 18 and is not irradiated onto the polygon mirror 14.
[0034]
In the configuration example shown in FIG. 7, the light shielding member 18 having a configuration in which the non-reflective tapes 18 b and 18 c are attached to the surface on the aperture 15 a side and the surface on the polygon mirror 14 side of the flat quadrangular columnar support material 18 a is provided on the polygon mirror 14. It is in the vicinity of the circumscribed circle, on the side opposite to the scanning area with respect to the path of parallel light from the aperture 15a, and provided in an area that does not obstruct the optical path. In this example, since such a light shielding member 18 exists, diffused light, which is noise light indicated by a broken line in FIG. 7, is absorbed or scattered on the surface of the light shielding member 18 and is not irradiated onto the polygon mirror 14. Further, as shown by a one-dot chain line in FIG. 7, even when diffused light that is noise light that reaches the polygon mirror 14 through the edge of the light shielding member 18 exists, the reflected light is absorbed by the back surface of the light shielding member 18. Or it is scattered and does not reach the light receiving element.
[0035]
Therefore, also in the second embodiment in which the light shielding member 18 having such a configuration is provided, the diffused light serving as noise light is prevented from entering the scanning optical system, as in the first embodiment. The edge of the signal is sharp, the boundary between the subsequent retroreflective signal is clear, and the reference signal and the retroreflective signal (scanning start signal) can be easily and accurately distinguished. In the second embodiment, since the light shielding member 18 is provided only in the vicinity of the polygon mirror 14, the area of the light shielding member 18 can be reduced as compared with the first embodiment.
[0036]
(Third embodiment)
FIG. 8 is a diagram showing the configuration and optical paths of the optical units 1a and 1b in the third embodiment. In FIG. 8, the same parts as those in FIG.
[0037]
In the third embodiment, a light shielding member 18 having an aperture having a scanning aperture width of the polygon mirror 14 is provided on the aperture mirror 15 side of the lens holder 20 that fixes the condenser lens 16. Other configurations, optical scanning operations, reference signal detection, and the like are the same as those in the first embodiment.
[0038]
The characteristics of the light shielding member 18 in the third embodiment will be described in detail. FIG. 9 is a schematic diagram of a configuration and an optical path of a conventional example in which such a light shielding member 18 does not exist, and FIG. 10 is a schematic diagram of a configuration and an optical path of a third embodiment in which the light shielding member 18 exists. In FIG. 9, the same parts as those in FIG.
[0039]
In the conventional example in which the light shielding member is not present, as shown by the solid line arrow in FIG. 9, when the scanning light from the polygon mirror 14 is irradiated to the aperture mirror 15 from an oblique direction, the reflected light is reflected on the inner surface of the lens holder 20. The light is scattered and reflected, and the scattered reflected light enters the light receiving element 13 as noise light. As a result, as shown in FIG. 11A, the width of the obtained reference signal is widened. Note that the hatched portion in FIG. 11A represents a noise component due to the scattered reflected light. Therefore, in the conventional example, since a wide reference signal is obtained, the boundary with the subsequent retroreflective signal (scanning start signal) becomes unclear, and it is difficult to distinguish both signals.
[0040]
On the other hand, in the third embodiment in which the light blocking member 18 is provided in the lens holder 20, the scanning light from the polygon mirror 14 is irradiated to the aperture mirror 15 in an oblique direction, as indicated by solid line arrows in FIG. Even in this case, the reflected light is blocked by the light shielding member 18 and is not incident on the light receiving element 13. As a result, as shown in FIG. 11B, an accurate reference signal consisting only of scanning light can be obtained. Therefore, in the third embodiment, since a reference signal having a narrow width is obtained, the boundary with the subsequent retroreflective signal (scanning start signal) becomes clear, and both signals can be easily and accurately distinguished. .
[0041]
(Fourth embodiment)
A fourth embodiment in which the reference signal and the retroreflected signal (scanning start signal) can be easily distinguished by narrowing the width of the reference signal will be described.
[0042]
FIG. 12 is a schematic diagram showing the arrangement design of the optical members of the optical unit 1a (1b) and the state of optical scanning. In the figure, δ is a scanning start angle (an angle formed by an optical axis of parallel light from the aperture 15a and an optical path of scanning light corresponding to Ps in FIG. 1), L1 is a distance from the aperture mirror 15 to the polygon mirror 14, w Denotes the width from the optical path of the scanning light in the aperture mirror 15 to the end on the detection area side (scanning area side). Therefore, when the beam width of the scanning light is d and the distance from the aperture mirror 15 to the light receiving element 13 is L2, if the following condition (1) is satisfied, the scanning light retroreflective sheet 7 The reflected light can be received by the light receiving element 13 without being blocked by the optical unit 1a (1b). And the position of each optical member is designed so that this condition (1) may be satisfied.
d / 2 + w> (L1 + L2) tan δ (1)
[0043]
When the design of the distance (L1) between the aperture mirror 15 and the polygon mirror 14 has a low degree of freedom and the length of L1 cannot be increased so much, the distance between the aperture mirror 15 and the light receiving element 13 while satisfying the condition (1) By setting (L2) to be long, the width of the reference signal can be reduced. FIG. 13 is a schematic diagram showing the positional relationship between these optical members when the polygon mirror 14 and the aperture mirror 15 are fixed, L1 is constant (30 mm), and the position of the light receiving element 13 is changed to change L2. FIG. Three positions of the light receiving element 13 are set ((1): L2 = 5 mm, (2): L2 = 10 mm, (3): L2 = 15 mm).
[0044]
FIG. 14 is an optical development when the optical member is arranged as shown in FIG. In FIG. 14, the reflection surface corresponds to the position of the polygon mirror 14, and the deflection surface corresponds to the position of the aperture mirror 15. FIG. 15 shows the reference signal and the subsequent retroreflection signal when the light receiving element 13 is arranged at each position.
[0045]
From FIG. 15, it can be seen that the width of the reference signal can be reduced by increasing L2, that is, by disposing the light receiving element 13 far from the aperture mirror 15. Therefore, when the distance (L2) between the light receiving element 13 and the aperture mirror 15 is increased, the width of the reference signal is shortened, and the reference signal and the retroreflective signal (scanning start signal) can be easily distinguished.
[0046]
Also, it can be seen that increasing L2 has the same effect as when the scanning start angle δ is increased from the relationship of condition (1).
[0047]
For example, when the distance (L1) between the aperture mirror 15 and the polygon mirror 14 is 10 mm and the scanning start angle δ is 20 °, the distance (L2) between the aperture mirror 15 and the light receiving element 13 is about 25 mm. You can do it.
[0048]
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. 16 is a schematic diagram showing an implementation state of the optical scanning touch panel. However, in FIG. 16, 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.
[0049]
The MPU 5 controls the polygon control circuit 4 to rotate the polygon mirrors 14 in the optical units 1a and 1b, thereby angle-scanning the laser beams from the light emitting elements 11. 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.
[0050]
In FIG. 16, θ00 and φ00 are angles from the reference line connecting both optical units 1a and 1b to each light receiving element, and θ0 and φ0 are the reference lines connecting both optical units 1a and 1b. The angle from the reference line to the reference line side end of the indicator S, and θ2 and φ2 are the angles from the reference line to the reference line of the indicator S and the opposite end. Each is shown. Here, (θ00 + θ0) or (φ00 + φ0) corresponds to the scanning start angle δ described above.
[0051]
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 shown in FIG. 16, 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.
[0052]
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. 17, 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 Px and Y-coordinate Py can be obtained by the following formulas (2) and (3) based on the principle of triangulation.
Px (θ, φ) = (tanφ) ÷ (tanθ + tanφ) × L (2)
Py (θ, φ) = (tan θ · tan φ) ÷ (tan θ + tan φ) × L (3)
[0053]
By the way, since the indicator S (finger) has a size, when the detection angle at the rising / falling timing of the detected light reception signal is adopted, as shown in FIG. Four points (P1 to P4 in FIG. 18) of the edge portion are detected. These four points are all different from the designated center point (Pc in FIG. 18). Therefore, the coordinates (Pcx, Pcy) of the center point Pc are obtained as follows. Pcx and Pcy can be expressed by the following equations (4) and (5), respectively.
Pcx (θ, φ) = Pcx (θ1 + dθ / 2, φ1 + dφ / 2) (4)
Pcy (θ, φ) = Pcy (θ1 + dθ / 2, φ1 + dφ / 2) (5)
[0054]
Therefore, by substituting θ1 + dθ / 2 and φ1 + dφ / 2 represented by the equations (4) and (5) as θ and φ in the above equations (2) and (3), the coordinates of the instructed center point Pc are obtained. Can be sought.
[0055]
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 (2) and (3) 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 (2) and (3), and the average of the obtained coordinate values of the four points is calculated. 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.
[0056]
By the way, when the scanning angular velocity of each polygon mirror 14 is constant, the information of the scanning angle can be obtained by measuring the time. FIG. 19 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 14 in the optical unit 1a. When the scanning angular velocity of the polygon mirror 14 is constant and 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 (6).
θ = ω × T (6)
[0057]
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 (7) and (8).
θ1 = ω × t1 (7)
θ2 = ω × t2 (8)
[0058]
Therefore, when the scanning angular velocity of the polygon mirror 14 is constant, it is possible to measure the blocking range and the coordinate position of the indicator S (finger) using the time information.
[0059]
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. 20 is a schematic diagram showing the principle of the cross-sectional length measurement. In FIG. 20, D1 and D2 are 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 (9) and (10).
OPc = r1 = (Pcx ² + Pcy ² ) ^1/2 (9)
BPc = r2 = {(L-Pcx) ² + Pcy ² } ^1/2 (10)
[0060]
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 (11) and (12).
D1 = r1 · 2sindθ / 2
= (Pcx ² + Pcy ² ) ^1/2 · 2 sin θ / 2 (11)
D2 = r2 · 2sindφ / 2
= {(L-Pcx) ² + Pcy ² } ^1/2 · 2 sin φ / 2 (12)
[0061]
In the case of θ, φ≈0, it can be approximated as sinθ≈dθ≈tandθ, sindφ≈dφ≈tandφ. Therefore, in the equations (11) and (12), dθ or tandθ, dφ instead of sindθ and sindφ. Alternatively, tandφ may be used.
[0062]
【The invention's effect】
As described above, in the present invention, since the light blocking means for blocking the noise light is provided so that the noise light does not reach the light scanning means, only the scanning light from the light scanning means is incident on the light receiving means. An accurate reference signal can be obtained, and the reference signal and the scan start signal can be easily distinguished.
[0063]
In addition, since the surface of the light shielding unit on the side of the optical scanning unit is subjected to non-reflection processing, even when noise light reaches the optical scanning unit, the reflected light is not incident on the light receiving unit, and the optical scanning is performed. Only the scanning light from the means is incident on the light receiving means, an accurate reference signal is obtained, and the reference signal and the scanning start signal can be easily discriminated.
[0064]
Since the light-shielding means having an aperture corresponding to the scanning aperture width of the optical scanning means is provided on the scanning light incident side of the light-receiving means, noise light does not reach the light-receiving means, and only the scanning light from the optical scanning means is received. By entering the light receiving means, an accurate reference signal can be obtained, and the reference signal and the scanning start signal can be easily distinguished.
[0065]
Since the optical member is arranged so as to satisfy the condition (1) described above, light can be scanned within a predetermined area and reflected light of the scanning light can be received. Further, since the distance (L2) from the deflecting means to the light receiving means is set to be long while satisfying the condition (1), the width of the reference signal can be reduced, and the discrimination between the reference signal and the scanning start signal is facilitated. Can be done.
[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 according to the first embodiment.
FIG. 3 is a diagram showing a configuration and an optical path in a conventional example without a light shielding member, a beam shape of light irradiated to a polygon mirror, a reference signal, and a retroreflection signal.
FIG. 4 is a diagram showing a configuration and an optical path, a beam shape of irradiation light to a polygon mirror, a reference signal, and a retroreflection signal in the first embodiment in which a light shielding member is present.
FIG. 5 is a diagram illustrating a configuration and an optical path of an optical unit according to a second embodiment.
FIG. 6 is a diagram illustrating a configuration and an optical path in an example of a second embodiment.
FIG. 7 is a diagram showing a configuration and an optical path in another example of the second embodiment.
FIG. 8 is a diagram illustrating a configuration and an optical path of an optical unit according to a third embodiment.
FIG. 9 is a diagram showing a configuration and an optical path in a conventional example in which no light shielding member is present.
FIG. 10 is a diagram illustrating a configuration and an optical path in a third embodiment in which a light shielding member is present.
FIG. 11 is a diagram illustrating a reference signal in the conventional example and the third embodiment of FIGS. 9 and 10;
FIG. 12 is a diagram showing an arrangement design of optical members of an optical unit and a state of optical scanning.
FIG. 13 is a diagram showing a positional relationship of optical members in the fourth embodiment.
FIG. 14 is an optical development view in the fourth embodiment.
FIG. 15 is a diagram showing a reference signal and a retroreflected signal in the fourth embodiment.
FIG. 16 is a schematic diagram showing an implementation state of the optical scanning touch panel.
FIG. 17 is a schematic diagram showing the principle of triangulation for coordinate detection.
FIG. 18 is a schematic diagram showing an indicator and a blocking range.
FIG. 19 is a timing chart showing a relationship among a light reception signal, a scanning angle, and a scanning time.
FIG. 20 is a schematic diagram showing the principle of cross-sectional length measurement.
[Explanation of symbols]
1a, 1b Optical unit 5 MPU
7 Retroreflective sheet 10 Display screen (coordinate plane)
DESCRIPTION OF SYMBOLS 11 Light emitting element 13 Light receiving element 14 Polygon mirror 15 Aperture mirror 16 Condensing lens 18 Light shielding member 18a Support material 18b, 18c Nonreflective tape 20 Lens holder S Indicator

Claims (2)

A light emitting means for emitting light; an optical scanning means for angularly scanning the light in a plane substantially parallel to a predetermined region; and a light receiving means for receiving scanning light from the optical scanning means. In an optical scanning touch panel that detects a blocking position of scanning light formed by an indicator in an area based on a light reception output of the light receiving unit corresponding to a scanning angle, between the light emitting unit and the optical scanning unit. In order to block the diffused light as noise light that does not become scanning light in a region that does not interfere with the path of the light emitted from the light emitting means, parallel light traveling from the light irradiating means to the optical scanning means An optical scanning type touch panel comprising a flat rectangular column-shaped light shielding means arranged along the longitudinal direction of the light shielding path, and a non-reflective treatment is applied to a portion of the light shielding means on the optical path side. Scanning light that includes an optical scanning unit that angularly scans light in a plane that is substantially parallel to the predetermined region, and a light receiving unit that receives scanning light from the optical scanning unit, and is formed of an indicator in the predetermined region In the optical scanning touch panel for detecting the blocking position of the light based on the light receiving output of the light receiving means corresponding to the scanning angle, a path of scanning light between the light scanning means and the light receiving means by the light scanning means In order to block diffused light as noise light that does not become scanning light in a region that does not hinder scanning light, a flat rectangular column-shaped light shielding means disposed along a path of parallel light from the light scanning means to the light receiving means And a non-reflective treatment is performed on a portion of the light shielding means on the optical path side.

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