JP4454667B2 - Optical scanning touch panel - Google Patents

Description

  The present invention relates to an optical scanning touch panel that optically detects the position of an indicator on a display screen.

  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.

  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 reflected 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, etc. can be detected.

Such an optical scanning touch panel that detects a position by using scanning light generally includes an optical retroreflector provided outside the display screen, a light emitting element that emits light such as laser light, and the emitted light. An optical scanning unit such as a polygon mirror for angle scanning, and a plurality of optical units including a light receiving element for receiving reflected light of the scanning light by a light retroreflector. The light is scanned by the optical scanning unit, the reflected light from the optical retroreflector of the scanned light is reflected again by the optical scanning unit, and the reflected light is 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 light 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 unit in each optical unit and the light reception result of the light receiving element.
Japanese Patent Laid-Open No. 11-085377 JP 05-045507 A

  In such an optical scanning touch panel, the light retroreflective property of the light retroreflector greatly affects the S / N ratio of the position detection of the indicator. It changes according to the incident angle. Therefore, in a conventional optical scanning touch panel using an optical retroreflector having one kind of optical retroreflective property, the optical retroreflective property may be deteriorated depending on the incident angle of the scanning light. There is a problem that the S / N ratio of position detection becomes low.

  The present invention has been made in view of such circumstances, and is provided with a plurality of light retroreflectors having different light retroreflective characteristics, whereby an optical scanning type capable of improving the S / N ratio of the position detection of an indicator. An object is to provide a touch panel.

  Another object of the present invention is to provide an optical scanning touch panel that can improve the S / N ratio of the position detection of an indicator by configuring the optical retroreflector so that the incident angle of the scanning light is approximately 0 degrees. It is to provide.

  Still another object of the present invention is to provide a protective material for protecting the light retroreflector, thereby preventing deterioration of the light retroreflective characteristics due to moisture, dust, etc. An object of the present invention is to provide an optical scanning touch panel capable of improving the ratio.

An optical scanning touch panel described in the present application includes an optical retroreflector provided outside a predetermined region, an optical scanning unit that angularly scans light in a plane substantially parallel to the predetermined region, and the optical scanning unit And a plurality of optical units having a light receiving portion for receiving the reflected light of the light retroreflector of the scanning light by the scanning light blocking position corresponding to the scanning angle formed by the indicator in the predetermined region In the optical scanning touch panel that detects based on the light reception output of the light receiving unit, the optical retroreflector is configured by combining a plurality of optical retroreflectors having different optical retroreflective characteristics. To do.

In the optical scanning touch panel described in the present application, a plurality of optical retroreflectors having different optical retroreflection characteristics are combined. For example, when the incident angle is small in a region where the incident angle is small in optical scanning. A light retroreflector having the strongest light retroreflective property is provided, and a light retroreflector having the strongest light retroreflective property is provided in a region where the incident angle is large in light scanning when the incident angle is large. Yes. Therefore, the optical retroreflective characteristic can be obtained according to the incident angle, and the S / N ratio for detecting the position of the pointing object can be improved.

An optical scanning touch panel described in the present application includes an optical retroreflector provided outside a predetermined region, an optical scanning unit that angularly scans light in a plane substantially parallel to the predetermined region, and the optical scanning unit And a plurality of optical units having a light receiving portion for receiving the reflected light of the light retroreflector of the scanning light by the scanning light blocking position corresponding to the scanning angle formed by the indicator in the predetermined region In the optical scanning touch panel that detects based on the light reception output of the light receiving unit, a part of the optical retroreflector has an incident surface inclined so that an incident angle of the scanning light becomes substantially 0 degree. It is characterized by being.

In the optical scanning touch panel described in the present application, the incident angle to the optical retroreflector is set to substantially 0 degrees, and the incident angle is small even in a region where the incident angle is large in optical scanning. When it is small, a light retroreflector having the strongest light retroreflective characteristic can be provided to improve the S / N ratio for detecting the position of the indicator.

Light scanning-type touch panel according to the present application, the surface of the front Symbol light retroreflector, characterized in that is provided with a protective material that protects the light retro-reflector.

In the optical scanning touch panel described in the present application, a protective material for protecting the optical retroreflector is provided, and the optical retroreflector is protected from moisture, dust, and the like.

Light scanning-type touch panel according to the present application is characterized in that the surface of the front Symbol protective material are subjected to antireflection processing.

In the optical scanning touch panel described in the present application, the surface of the protective material is subjected to an anti-reflection treatment, and a decrease in the amount of light due to reflection on the surface of the protective material is suppressed, so that the S / The N ratio can be improved.

Light scanning-type touch panel according to the present application, for any angle of incidence of the scanning light Previous Stories light retroreflector, characterized in that are optimized for light reflection prevention treatment of the protective material.

In the optical scanning touch panel described in the present application, the light-reflective treatment of the protective material is optimized for an arbitrary incident angle on the optical retroreflector, and the light amount due to reflection on the surface of the protective material. It is possible to suppress the decrease and improve the S / N ratio of the position detection of the pointing object.

Light scanning-type touch panel according to the present application, the pre-Symbol protective material, and having a deflecting function to change the direction of the scanning light.

In the optical scanning touch panel described in the present application , the protective material has a deflection function that changes the direction of the scanning light, and the incident angle of the indicator is adjusted by adjusting the incident angle with respect to the optical retroreflector by the protective material. The S / N ratio for position detection can be improved.

  In the present invention, since a plurality of light retroreflectors having different light retroreflective characteristics are combined, an optimal light retroreflective characteristic can be obtained according to the incident angle, and the position of the indicator can be detected. It is possible to improve the / N ratio.

  In addition, since the incident angle to the optical retroreflector is substantially 0 degree in the region where the incident angle in the optical scanning is large, when the incident angle is small even though the region is originally in the region where the incident angle is large. A light retroreflector having the strongest light retroreflective property can be provided, and the S / N ratio for detecting the position of the indicator can be improved.

  In addition, since the protective material for protecting the light retroreflector is provided, the light retroreflector can be protected from moisture, dust and the like.

  In addition, since the antireflection treatment is applied to the surface of the protective material, it is possible to suppress the decrease in the amount of light due to the reflection on the surface of the protective material and to improve the S / N ratio of the position detection of the indicator. It is.

  In addition, since the light-reflective treatment of the protective material is optimized for any incident angle on the light retroreflector, the light quantity reduction due to reflection on the surface of the protective material is suppressed, and the indicator It is possible to improve the S / N ratio of the position detection.

  In addition, since the protective material has a deflecting function for changing the direction of light, the incident angle with respect to the light retroreflector is adjusted by the protective material to improve the S / N ratio of the position detection of the indicator. It is possible.

  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.

  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.

  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 light retroreflector is fixed to the housing 8 on the three sides excluding the right side of the display screen 10, that is, on the outer sides of both the upper and lower sides and the left side. Is provided. In the present invention, the retroreflective sheet 7 is configured by combining two types of retroreflective sheets 7a and 7b having different light retroreflective characteristics. In the region where the incident angle is small (the entire region on the left side and the right region close to the optical units 1a and 1b on both the upper and lower sides), the low incident angle having the strongest light retroreflective characteristics when the incident angle is small. The retroreflective sheet 7a is provided, and the region where the incident angle is large (the left region far from the optical units 1a and 1b on the upper and lower sides) has the strongest light retroreflective characteristic when the incident angle is large. Is provided with a retroreflective sheet 7b for high incident angles. Details of these retroreflective sheets 7a and 7b will be described later.

  FIG. 2 is a perspective view showing the configuration of the optical system and the optical path in the optical units 1a and 1b. Both optical units 1a and 1b have the same optical system. The optical units 1a and 1b include a light emitting element 11 formed 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 ( 7a and 7b), a light receiving element 13 composed of a photodiode (PD) for receiving reflected light, a slit plate 14 having a slit 14a for limiting incident light to the light receiving element 13, and a laser from the light emitting element 11. The projection light from the collimation lens 12 to the polygon mirror 15 is limited by, for example, a quadrangular prism-shaped polygon mirror 15 for angle scanning of the light and the aperture 16a, and the retroreflective sheet 7 (7a, 7a, 7a, An aperture mirror 16 for reflecting the reflected light from 7b) toward the light receiving element 13, and an aperture mirror; It comprises a condenser lens 17 for focusing the light reflected at 16, a motor 18 for rotating the polygon mirror 15, an optical unit main body 19 for fixing the mounting of these optical members.

  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. Is projected on the retroreflective sheet 7 (7a, 7b). Then, after the reflected light from the retroreflective sheet 7 (7a, 7b) is reflected by the polygon mirror 15 and the aperture mirror 16, it is focused by the condenser lens 17 and passes through the slit 14a of the slit plate 14, The light enters the light receiving element 13. 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.

  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 that controls the operation of 15 and synchronizes the start of optical scanning in each of the optical units 1a and 1b is connected. 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.

  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.

  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 (7a), and becomes a substantial scanning start position. And until the position (P1) reaching one end of the indicator S is reflected by the retroreflective sheet 7 (7a), it is blocked by the indicator S until the position (P2) reaching the other end of the indicator S. Then, the light is reflected by the retroreflective sheet 7 (7a, 7b) until the subsequent scanning end position (Pe).

  Next, the retroreflective sheet 7 constituting the characteristic part of the present invention will be described. FIG. 3 is a schematic diagram showing the configuration of the main part of the optical scanning touch panel of the present invention. As described above, the retroreflective sheet 7 is composed of a retroreflective sheet 7a for a low incident angle and a retroreflective sheet 7b for a high incident angle. As shown in FIG. A retroreflective sheet 7a for a low incident angle is provided in a region from 0 to 30 degrees, and a retroreflective sheet 7b for a high incident angle is provided in a region where the incident angle exceeds 30 degrees (maximum 60 degrees). Is provided.

  FIG. 4 is a graph showing the light retroreflective characteristics of both retroreflective sheets 7a and 7b. In FIG. 4, the horizontal axis represents the incident angle (degrees), and the vertical axis represents the reflected light (μW). ●-● represents the retroreflective characteristic of the retroreflective sheet 7a for a low incident angle. The circles indicate the light retroreflective characteristics of the retroreflective sheet 7b for high incident angles. From FIG. 4, the retroreflective sheet 7 a for low incident angles has a light retroreflective characteristic that decreases as the incident angle increases, and the retroreflective sheet 7 b for high incident angles increases the incident angle to about 50 degrees. It can be seen that the light retroreflective properties of both retroreflective sheets 7a and 7b match when the light retroreflective property increases and the incident angle is about 30 degrees. Therefore, as shown in FIG. 3, the retroreflective sheet 7a for the low incident angle is used in the region where the incident angle is 0 degree to 30 degrees, and the recursive for the high incident angle is used in the region where the incident angle is larger than 30 degrees. By using the reflective sheet 7b, it is possible to improve the S / N ratio of the position detection of the indicator S.

  FIG. 5 is an enlarged view of the boundary portion between the two retroreflective sheets 7a and 7b. At this boundary portion, the retroreflective sheets 7a and 7b are overlapped so that the retroreflective sheet 7a with the earlier optical scanning order is positioned above the retroreflective sheet 7b with the slower light scanning order. Therefore, since both the retroreflective reflection sheets 7a and 7b are overlapped at the boundary portion, it is possible to prevent a situation where the reflected light cannot be detected at the boundary portion. Such a configuration of the boundary portion is particularly necessary when the beam size of the scanning light is small. In addition, it is sufficient that no gap is formed between the retroreflective sheets 7a and 7b adjacent to each other at the boundary portion, and the configuration of the boundary portion such that both the retroreflective sheets 7a and 7b are in contact with each other as shown in FIG. It may be.

  In the above-described example, the light retroreflector is configured by combining two types of retroreflective sheets 7a and 7b having different light retroreflective characteristics. Of course, the light retroreflector may be configured by combining the reflective sheets.

  7 and 8 are a schematic view and a cross-sectional view showing a configuration of a main part of another optical scanning touch panel according to the present invention. 7 and 8, the same parts as those in FIGS. 3 and 5 are denoted by the same reference numerals. In this example, a protective cover 21 made of fluorine Teflon (registered trademark) resin is provided so as to be guided by the groove 8a of the housing 8 and cover the retroreflective sheet 7 (7a, 7b).

  By providing such a protective cover 21, the retroreflective sheet 7 (7 a, 7 b) is protected against moisture, dust, etc., so the retroreflective sheet 7 (7 a, 7 b) due to adhesion of moisture, dust, etc. ) Can be prevented from deteriorating.

  Antireflection treatment is applied to the surface of the protective cover 21 so that almost all light passes through the protective cover 21 and a sufficient amount of reflected light is obtained from the retroreflective sheet 7 (7a, 7b). It is preferable to keep it. FIG. 9 is a cross-sectional view showing this antireflection treatment. For example, an antireflection film 22 is formed on the light incident surface of the retroreflective sheet 7 (7a, 7b). By performing such an antireflection treatment, reflection of the scanning light on the surface of the protective cover 21 can be prevented, and a reduction in the level of reflected light on the retroreflective sheet 7 (7a, 7b) due to the reflection is suppressed. This leads to an improvement in the S / N ratio.

  In such an antireflection treatment (formation of the antireflection film 22), the antireflection film 22 is formed so that the optical path length of the scanning light in the antireflection film 22 is λ / 4 (λ: the wavelength of the scanning light). By controlling the film thickness, the antireflection characteristic can be set optimally for an arbitrary incident angle. Therefore, for example, the low reflection angle retroreflective sheet 7a having the characteristics shown in FIG. 4 is used so that the antireflection characteristics with respect to the incident angle with a low S / N ratio (the amount of reflected light is small) are optimized. In this case, when the antireflection characteristic is optimized in the range of the incident angle of 15 to 30 degrees where the amount of reflected light is reduced, the S / N ratio of the position detection of the indicator S at the incident angle is improved. It is possible.

  FIG. 10 is a schematic diagram showing the configuration of the main part of still another optical scanning touch panel of the present invention, and FIG. 11 is a partially enlarged view of FIG. 10 and 11, the same parts as those in FIGS. 7 and 8 are denoted by the same reference numerals. In this example, in a region where the incident angle of the scanning light is large (greater than 30 degrees), a plurality of retroreflective sheets 7a for low incident angles are tilted so that the incident angle is approximately 0 degrees. Provided. Each of these retroreflection sheets 7a is fixed by each support member 23 arranged in a line at a pitch of about 5 to 6 mm. The configuration in the region where the incident angle is small (30 degrees or less) is the same as the example shown in FIGS.

  In such an example, the incident angle to the retroreflective sheet 7 (7a) can be made substantially 0 degrees even in a region where the incident angle is large, and the S / N for detecting the position of the indicator S can be reduced. It is possible to improve the ratio.

  FIG. 12 is a schematic diagram showing a configuration of a main part of still another optical scanning touch panel of the present invention, and FIG. 13 is a partially enlarged sectional view of FIG. 12 and 13, the same parts as those in FIGS. 7 and 8 are denoted by the same reference numerals. In this example, the retroreflective sheet 7a for low incident angles is provided in all regions as a light retroreflector, and is in a region where the incident angle is large (greater than 30 degrees), for low incident angles. The upper surface of the retroreflective sheet 7a is covered with a protective cover 24 with a deflecting function having a light deflecting function. For example, a prism sheet can be used for the protective cover 24 with a deflection function. The configuration in the region where the incident angle is small (30 degrees or less) is the same as the example shown in FIGS.

  In such a configuration, even in a region where the incident angle is originally large, the incident angle to the retroreflective sheet 7 (7a) by the protective cover 24 with a deflection function as shown in FIG. Thus, the S / N ratio for detecting the position of the indicator S can be improved.

  Finally, 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. 14 is a schematic diagram showing an implementation state of the optical scanning touch panel. However, in FIG. 14, components other than the optical units 1a and 1b, the retroreflective sheet 7 (7a and 7b), and the display screen 10 are not shown. Moreover, the case where a finger is used as the pointing object S is shown.

  The MPU 5 controls the polygon control circuit 4 to rotate the polygon mirrors 15 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.

  In FIG. 14, θ00 and φ00 are the angles from the scanning reference line to each light receiving element, θ0 and φ0 are the angles from the scanning reference line to the end of the retroreflective sheet 7 (7a, 7b), θ1, φ1 indicates the angle from the scanning reference line to the reference line side end of the indicator S, and θ2 and φ2 indicate the angles from the scanning reference line to the reference line of the indicator S and the opposite end.

  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. 14, 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.

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. 15, 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 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)

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. 16) of the edge portion are detected. These four points are all different from the designated center point (Pc in FIG. 16). 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)

  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.

  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.

By the way, when the scanning angular velocity of each polygon mirror 15 is constant, the information of the scanning angle can be obtained by measuring the time. FIG. 17 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)

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)

  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.

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. 18 is a schematic diagram showing the principle of the cross-sectional length measurement. In FIG. 18, 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 (8) and (9).
OPc = r1 = (Pcx ² + Pcy ² ) ^1/2 (8)
BPc = r2 = {(L-Pcx) ² + Pcy ² } ^1/2 (9)

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 · 2 sin θ / 2 = (Pcx ² + Pcy ² ) ^1/2 · 2 sin θ / 2
(10)
D2 = r2 · 2 sin φ / 2 = {(L−Pcx) ² Pcy ² } ^1/2 · 2 sin φ / 2
... (11)

  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.

It is a schematic diagram which shows the basic composition of the optical scanning touch panel of this invention. It is a perspective view which shows the structure and optical path of the optical system in an optical unit. It is a schematic diagram which shows the structure of the principal part of the optical scanning touch panel of this invention. It is a graph which shows the light retroreflection characteristic of two types of retroreflection sheets. It is an enlarged view of the boundary part of two types of retroreflection sheets. It is an enlarged view of the boundary part of two types of retroreflection sheets. It is a schematic diagram which shows the structure of the principal part of the other optical scanning touch panel of this invention. It is sectional drawing which shows the structure of the principal part of the other optical scanning touch panel of this invention. It is sectional drawing which shows the reflection preventing process of a protective cover. It is a schematic diagram which shows the structure of the principal part of the other optical scanning touch panel of this invention. It is the elements on larger scale of FIG. It is a schematic diagram which shows the structure of the principal part of the other optical scanning touch panel of this invention. It is a partial expanded sectional view of FIG. It is a schematic diagram which shows the implementation state of an optical scanning touch panel. It is a schematic diagram which shows the principle of the triangulation for coordinate detection. It is a schematic diagram which shows an indicator and the interruption | blocking range. It is a timing chart which shows the relationship between a received light signal, a scanning angle, and scanning time. It is a schematic diagram which shows the principle of cross-section length measurement.

Explanation of symbols

1a, 1b Optical unit 5 MPU
7 Retroreflective sheet 7a Retroreflective sheet for low incident angle 7b Retroreflective sheet for high incident angle 8 Case 10 Display screen (coordinate plane)
DESCRIPTION OF SYMBOLS 11 Light emitting element 13 Light receiving element 15 Polygon mirror 21 Protective cover 22 Antireflection film 23 Support material 24 Protective cover with a deflection function S Indicator

Claims (2)

An optical unit provided outside a target area for touching by an indicator and having a light emitting element and a light receiving element that receives reflected light of the light emitted from the light emitting element;
A retroreflector provided outside the target area and reflecting light emitted from the light emitting element;
With
The retroreflector is a combination of a first retroreflective sheet and a second retroreflective sheet having different reflection characteristics with respect to an incident angle,
The first retroreflective sheet has a light retroreflective property with respect to light having an incident angle smaller than a predetermined angle, higher than the second retroreflective sheet,
The second retroreflective sheet has a light retroreflective property with respect to light having an incident angle greater than the predetermined angle, which is higher than the first retroreflective sheet,
The boundary between the first retroreflective sheet and the second retroreflective sheet is arranged so that the first retroreflective sheet is closer to the target area than the second retroreflective sheet. An optical scanning touch panel characterized by that. An optical unit provided outside a target area for touching by an indicator and having a light emitting element and a light receiving element that receives reflected light of the light emitted from the light emitting element;
A retroreflector provided outside the target area and reflecting light emitted from the light emitting element;
With
The retroreflector is a combination of a first retroreflective sheet and a second retroreflective sheet having different reflection characteristics with respect to an incident angle,
The first retroreflective sheet has a light retroreflective property with respect to light having an incident angle smaller than a predetermined angle, higher than the second retroreflective sheet,
The second retroreflective sheet has a light retroreflective property with respect to light having an incident angle greater than the predetermined angle, which is higher than the first retroreflective sheet,
The boundary between the first retroreflective sheet and the second retroreflective sheet is arranged so that the end of the first retroreflective sheet and the end of the second retroreflective sheet are in contact with each other. An optical scanning touch panel characterized by that.

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