JP2000293311A - Optical scanning type touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical scanning touch panel capable of improving the S/N ratio of position detection of an indicated object. SOLUTION: This optical scanning touch panel scans light from optical units 1a and 1b on a display screen 10, receives reflected light from recursive reflection sheets 7 by the units 1a and 1b and detects the interruption position of scan light formed by an instructed object S on the basis of the light receiving output of reflected light corresponding to a scanning angle. In such a case, recursive reflection sheets 7a for a small incident angle having a light recursive reflection characteristic that becomes the strongest when an incident angle is small are provided in areas where an incident angle is small, and recursive reflection sheets 7b for a large incident angle having a light recursive reflection characteristic that becomes the strongest when an incident angle is large are provided in areas where an incident angle is large.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning type touch panel for optically detecting the position of a pointer on a display screen.

[0002]

2. Description of the Related Art With the spread of computer systems such as personal computers, new information is obtained by pointing a display screen of a display device on which information is displayed by the computer system with a human finger or a specific indicator. For example, a device for inputting an instruction or giving various instructions to a computer system is used.

When an input operation is performed on information displayed on a display screen of a display device such as a personal computer by a touch method, a contact position (pointed position) on the display screen is detected with high accuracy. There is a need. As an example of a method of detecting a designated position on a display screen which is a coordinate plane, an optical position detection method is disclosed in Japanese Patent Application Laid-Open No. 62-5428.
Has been proposed. This method arranges light retroreflectors on both side frames of a display screen, detects reflected light of an angle-scanned laser beam from this light retroreflector, and detects the timing at which the light 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, the detection accuracy can be maintained, and the position of a finger, an arbitrary pen or the like can be detected.

An optical scanning type touch panel which performs position detection by using such scanning light generally has a light retroreflector provided outside a display screen, a light emitting element for emitting light such as laser light, and a light emitting element. An optical scanning unit such as a polygon mirror that angularly scans the scanned light, and a plurality of optical units including a light receiving element that receives light reflected by the light retroreflector of the scanned light, and in each optical unit, The light scanning unit scans light from the light emitting element, and the light reflected by the light retroreflector of the scanning light is reflected again by the light scanning unit, and the reflected light is received by the light receiving element. I have. If an indicator such as a finger or an arbitrary pen exists in the path of the scanning light, the light reflected by the light retroreflector is not received by the light receiving element. Therefore, the positions of the pointers can be detected based on the scanning angle of the optical scanning unit in each optical unit and the result of light reception by the light receiving element.

[0005]

In such an optical scanning type touch panel, the light retroreflection characteristics of the light retroreflector greatly affect the S / N ratio for detecting the position of the pointer. This light retroreflection characteristic changes according to the incident angle of light. Therefore, in the conventional light scanning type touch panel using the light retroreflector having one kind of light retroreflection characteristics, the light retroreflection characteristics may be deteriorated depending on the incident angle of the scanning light, and the indicator There is a problem that the S / N ratio for position detection is low.

The present invention has been made in view of such circumstances, and by providing a plurality of light retroreflectors having different light retroreflection characteristics, it is possible to improve the S / N ratio of position detection of an indicator. An object is to provide an optical scanning type touch panel.

Another object of the present invention is to provide an optical scanning system capable of improving the S / N ratio for detecting the position of an indicator by configuring a light retroreflector so that the incident angle of the scanning light is substantially zero degrees. It is to provide a type touch panel.

Still another object of the present invention is to provide a protective material for protecting the light retroreflector so as to prevent deterioration of the light retroreflection characteristics due to moisture, dust, etc. An object of the present invention is to provide an optical scanning type touch panel capable of improving the S / N ratio.

[0009]

According to a first aspect of the present invention, there is provided an optical scanning type touch panel, comprising: a light retroreflector provided outside a predetermined area; and an angle of light in a plane substantially parallel to the predetermined area. A plurality of optical units each having a light scanning unit for scanning and a light receiving unit for receiving the light reflected by the light retroreflector on the scanning light by the light scanning unit; and a scan formed by an indicator in the predetermined area. In a light scanning type touch panel that detects a light blocking position based on a light receiving output of the light receiving unit corresponding to a scanning angle, the light retroreflector includes a plurality of light retroreflectors having different light retroreflection characteristics. It is characterized by being configured in combination.

In the optical scanning type touch panel according to the present invention, a plurality of light retroreflectors having different light retroreflection characteristics are combined. A light-retroreflector having the strongest light-retroreflection property when small is provided, and a light-retroreflector having the strongest light-retroreflection property when the incident angle is large in a region where the incident angle is large in optical scanning in the light scanning. Is provided. Therefore, it is possible to have an optimal light retroreflection characteristic according to the incident angle, and it is possible to improve the S / N ratio for detecting the position of the pointer.

The optical scanning type touch panel according to claim 2 is
A light retroreflector provided outside a predetermined region, an optical scanning unit for angularly scanning light in a plane substantially parallel to the predetermined region, and the light retroreflector of scanning light by the light scanning unit A plurality of optical units each having a light receiving unit for receiving the reflected light from the light receiving unit, and detecting a blocking position of the scanning light formed by the indicator in the predetermined area based on a light receiving output of the light receiving unit corresponding to a scanning angle. In an optical scanning type touch panel, a part of the light retroreflector has an incident angle of scanning light of substantially zero.
It is characterized in that the incident surface is inclined so as to be at a right angle.

In the optical scanning type touch panel according to the second aspect, the incident angle to the light retroreflector is set to substantially 0 degree, and even if the incident angle is large in the light scanning. By providing a light retroreflector having the strongest light retroreflection characteristics when the incident angle is small, the S / N ratio for detecting the position of the pointer can be improved.

According to a third aspect of the present invention, there is provided an optical scanning type touch panel.
In Claim 1 or 2, a protective material for protecting the light retroreflector is provided on a surface of the light retroreflector.

In the optical scanning type touch panel according to the third aspect of the present invention, a protective material for protecting the light retroreflector is provided, and the light retroreflector is protected from moisture, dust and the like.

According to a fourth aspect of the present invention, there is provided an optical scanning type touch panel.
According to a third aspect of the present invention, the surface of the protective material is subjected to a light reflection preventing treatment.

In the optical scanning type touch panel according to the present invention, the surface of the protective material is subjected to an anti-reflection treatment so as to suppress a decrease in the amount of light due to the reflection on the surface of the protective material and detect the position of the pointer. Can be improved.

An optical scanning type touch panel according to claim 5 is
According to a fourth aspect of the present invention, the antireflection processing of the protective material is optimized for an arbitrary incident angle of the scanning light on the light retroreflector.

In the optical scanning type touch panel according to the fifth aspect, the antireflection treatment of the protective material is optimized for an arbitrary angle of incidence on the light retroreflector, and the surface of the protective material is protected from light reflection. The amount of light reduction due to reflection is suppressed, and the S
/ N ratio can be improved.

An optical scanning type touch panel according to claim 6 is
According to a third aspect of the present invention, the protection member has a deflection function of changing the direction of the scanning light.

In the optical scanning type touch panel according to the present invention, the protective member has a deflecting function of changing the direction of the scanning light, and adjusts an incident angle with respect to the light retroreflector by the protective member. The S / N ratio for detecting the position of the pointer can be improved.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. FIG. 1 is a schematic diagram showing a basic configuration of an optical scanning type touch panel of the present invention.

In FIG. 1, reference numeral 10 denotes a rectangular display screen such as a CRT or a flat display panel (PDP, LCD, EL, etc.) in an electronic device such as a personal computer, a projection type video display device, etc. In the embodiment, it is configured as a display screen of a PDP (plasma display).

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 for touching with 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 kinds of lenses, and the like are provided outside the both corners.

Except for the right side of the display screen 10, 3
A retroreflective sheet 7 as a light retroreflector is fixed to the housing 8 on the sides, that is, outside the upper and lower sides and the left side. 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 near the optical units 1a and 1b on both the upper and lower sides), a low incident angle having the strongest light retroreflection characteristic when the incident angle is small. In the area where the incident angle is large (the area on the left side far from the optical units 1a and 1b on the upper and lower sides) where the incident angle is large, the strongest light retroreflection characteristic is obtained when the incident angle is large. And a retroreflective sheet 7b for high incidence angles having the following. Details of these retroreflective sheets 7a and 7b will be described later.

FIG. 2 is a perspective view showing the configuration of an optical system and optical paths 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 composed of a laser diode (LD) for emitting infrared laser light, and a light emitting element 11
A collimation lens 12 for converting the laser light from the laser beam into parallel light, a light receiving element 13 composed of a photodiode (PD) for receiving light reflected from the retroreflective sheet 7 (7a, 7b), and a light receiving element 13 A slit plate 14 having a slit 14a for limiting incident light, a polygon mirror 15 having, for example, a quadrangular prism shape for angularly scanning a laser beam from the light emitting element 11, and an aperture 16a from the collimation lens 12 to the polygon mirror 15. And an aperture mirror 16 that reflects the light reflected from the retroreflective sheet 7 (7a, 7b) via the polygon mirror 15 to the light receiving element 13 and focuses the light reflected by the aperture mirror 16. Condensing lens 17 for rotating and a motor 18 for rotating the polygon mirror 15
And an optical unit main body 19 for mounting and fixing each of these optical members.

The laser light emitted from the light emitting element 11 is
After being converted into parallel light by the collimation lens 12 and passing through the aperture 16a of the aperture mirror 16, the polygon mirror 15 is rotated to scan an angle in a plane substantially parallel to the display screen 10, and the retroreflective sheet 7 ( 7
a, 7b). And the retroreflective sheet 7
The reflected light from (7a, 7b) is reflected by the polygon mirror 15 and the aperture mirror 16, is then focused by the condenser lens 17, passes through the slit 14a of the slit plate 14, and enters the light receiving element 13. . However, when the indicator S exists in the path of the scanning light, the projection light is blocked, so that the reflected light does not enter the light receiving element 13.

Each of the optical units 1a and 1b includes a light emitting element driving circuit 2a and 2b for driving each light emitting element 11, a light receiving signal detecting circuit 3a and 3b for converting the amount of light received by each light receiving element 13 into an electric signal, A scanning synchronization control circuit 4 for controlling the operation of each polygon mirror 15 and synchronizing 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 pointer S and controls the operation of the entire apparatus.
This is a display device that displays the calculation results and the like in the PU5.

The MPU 5 includes light emitting element drive circuits 2a, 2b
The light emitting element driving circuits 2a and 2b are driven according to the driving control signal, and the light emitting elements 11
Is controlled. Light receiving signal detection circuits 3a, 3b
Sends a light receiving signal from each light receiving element 13 to the MPU 5. M
PU5 is based on the light receiving signal from each light receiving element 13,
The position and size of the pointer S are calculated, and the calculation result is displayed on the display device 6. The display device 6 can also serve as the display screen 10.

In such an optical scanning type touch panel according to the present invention, as shown in FIG. 1, for example, the optical unit 1b will be described. 1 is scanned counterclockwise on FIG. 1, and the retroreflective sheet 7 (7
The position (Ps) where the light is reflected at the leading end portion of FIG. The light is reflected by the retroreflective sheet 7 (7a) up to the position (P1) reaching one end of the pointer S, but is blocked by the pointer S until the position (P2) reaching the other end of the pointer S. The retroreflective sheet 7 (7a, 7a,
7b).

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

FIG. 4 is a graph showing light retroreflection characteristics of the two retroreflective sheets 7a and 7b. In FIG. 4, the horizontal axis represents the incident angle (degrees), the vertical axis represents the reflected light (μW), and ● − ● represents the retroreflective sheet 7 for a low incident angle.
The light retroreflection characteristic of a, and −- ○ indicate the light retroreflection characteristics of the retroreflection sheet 7b for a high incident angle. From FIG. 4, the light retroreflection characteristics of the retroreflective sheet 7a for a low incident angle decrease as the incident angle increases, and the incident angle of the retroreflective sheet 7b for a high incident angle increases to about 50 degrees. As a result, the light retroreflection characteristic increases, and the incident angle becomes about 30.
It can be seen that the light retroreflection characteristics of the two retroreflective sheets 7a and 7b coincide with each other. Therefore, as shown in FIG. 3, in the region where the incident angle is from 0 degree to 30 degrees, the retroreflective sheet 7a for the low incident angle is used, and the incident angle is 3 degrees.
By using the retroreflective sheet 7b for a high incident angle in a region larger than 0 degree, the S / S
It is possible to improve the N ratio.

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

In the example described above, the light retroreflector is constituted by a combination of two kinds of retroreflective sheets 7a and 7b having different light retroreflection characteristics. It goes without saying that a light retroreflector may be configured by combining the above retroreflective sheets.

FIGS. 7 and 8 are a schematic view and a sectional view showing the structure of the main part of another optical scanning type 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 a fluorine-based 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 (7a, 7b) is protected against moisture, dust, etc., so that the retroreflective sheet 7 (7a, 7b) due to adhesion of moisture, dust, etc. 7a, 7b) can be prevented from deteriorating.

The protective cover 21 is so arranged that almost all the 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 that an anti-reflection treatment is applied to the surface of.
FIG. 9 is a cross-sectional view showing the anti-reflection process. For example, an anti-reflection film 22 is formed on the light incident surface of the retroreflective sheet 7 (7a, 7b). By performing such an anti-reflection treatment, it is possible to prevent the scanning light from being reflected on the surface of the protective cover 21, and to suppress a decrease in the level of the reflected light on the retroreflective sheet 7 (7a, 7b) due to the reflection. And leads to an improvement in the S / N ratio.

Such an antireflection treatment (the antireflection film 22)
), The incident light is controlled by controlling the thickness of the antireflection film 22 so that the optical path length of the scanning light on the antireflection film 22 becomes λ / 4 (λ: wavelength of the scanning light). The antireflection characteristics can be optimally set for the corners. Therefore, for example, the retroreflective sheet 7a for the low incident angle having the characteristics as shown in FIG. 4 so that the antireflection characteristics for the incident angle with a low S / N ratio (the amount of reflected light is small) are optimized.
15 to 30 when the amount of reflected light is reduced
When the anti-reflection characteristic is optimized in the range of the incident angle in degrees, the S / N of the position detection of the pointer S at the incident angle is considered.
It is possible to improve the ratio.

FIG. 10 is a schematic view showing the structure of a main part of still another optical scanning type touch panel according to the present invention, and FIG.
It is the elements on larger scale of 0. 10 and 11, the same parts as those in FIGS. 7 and 8 are denoted by the same reference numerals. In this example, the incident angle of the scanning light becomes large (exceeds 30 degrees).
In the area, a plurality of low-incidence-angle retroreflective sheets 7a are provided so as to be inclined so that the incident angle becomes substantially 0 degrees. These respective retroreflective sheets 7a are fixed by the support members 23 arranged in a row 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, even in a region where the incident angle is originally large, the retroreflective sheet 7 can be used.
The incident angle to (7a) can be made substantially 0 degree, and the S / N ratio for detecting the position of the pointer S can be improved.

FIG. 12 is a schematic view showing the structure of a main part of still another optical scanning type touch panel according to the present invention, and FIG.
2 is a partially enlarged sectional view of FIG. In FIG. 12 and FIG.
7 and 8 are denoted by the same reference numerals. In this example, a retroreflective sheet 7a for a low incident angle is provided in all regions as a light retroreflector, and in a region where the incident angle is large (exceeding 30 degrees), The upper surface of the retroreflective sheet 7a is covered with a protective cover 24 having 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 the case of such a configuration, even in a region where the incident angle is originally large, as shown in FIG. 13, the protective cover 24 with a deflecting function allows the retroreflective sheet 7 (7a) to be formed. Can be made substantially zero degree, and the S / N ratio for detecting the position of the pointer S can be improved.

Finally, the operation of calculating the position and size of the pointer S by the optical scanning type touch panel of the present invention will be described. FIG. 14 is a schematic diagram illustrating an implementation state of the optical scanning touch panel. However, in FIG. 14, the optical units 1a, 1
b, retroreflective sheet 7 (7a, 7b), display screen 10
The other components are not shown. In addition, the indicator S
Shows a case where a finger is used.

The MPU 5 controls the polygon control circuit 4 to rotate the polygon mirrors 15 in the optical units 1a and 1b to scan the laser light from the light emitting elements 11 at an angle. As a result, the reflected light from the retroreflective sheet 7 enters each light receiving element 13. In this way, the amount of light received by each light receiving element 13 is obtained as a light receiving signal which is an output of the light receiving signal detecting circuits 3a and 3b.

In FIG. 14, θ00 and φ00 are angles from the scanning reference line to each light receiving element, and θ0 and φ0 are angles from the scanning reference line to the end of the retroreflective sheet 7 (7a, 7b). , Θ1 and φ1 indicate the angles from the scanning reference line to the reference line side end of the pointer S, and θ2 and φ2 indicate the angles from the scanning reference line to the reference line and the opposite end of the pointer S, respectively. .

The indicator S is placed on the optical path of the scanning light on the display screen 10.
Exists, the reflected light from the indicator S of the light projected from the optical units 1a and 1b does not enter each light receiving element 13. Therefore, in the state as shown in FIG. 14, no reflected light is incident on the light receiving element 13 in the optical unit 1a when the scanning angle is between 0 ° and θ0, and the scanning angle is between 0 ° and θ1. The reflected light is incident on the light receiving element 13 during the interval, and the reflected light is not incident on the light receiving element 13 when the scanning angle is between θ1 and θ2. Similarly, when the scanning angle is between 0 ° and φ0, no reflected light is incident on the light receiving element 13 in the optical unit 1b, and the scanning angle is φ
The reflected light is incident on the light receiving element 13 from 0 to φ1, and the reflected light is not incident on the light receiving element 13 when the scanning angle is from φ1 to φ2.

Next, a description will be given of a process for obtaining the coordinates of the center position (pointed position) of the pointing object S (in this example, the finger) from the blocking range thus obtained. First, conversion from an angle to rectangular coordinates based on triangulation 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 (the distance between the optical units 1a and 1b) is set to L. And Further, the position of the optical unit 1b is assumed to be B. Display screen 10
When the center point P (Px, Py) pointed by the above pointer S is located at an angle of θ or φ with respect to the X axis from the optical units 1a, 1b, respectively, the X coordinate Px, Y of the point P. The value of the coordinate Py can be obtained by the following equations (1) and (2), respectively, based on the principle of triangulation. Px (θ, φ) = (tanφ) ÷ (tanθ + tanφ) × L (1) Py (θ, φ) = (tanθ · tanφ) ÷ (tanθ + tanφ) × L (2)

By the way, since the pointing object S (finger) has a size, when the detected angle at the rising / falling timing of the detected light receiving signal is adopted, as shown in FIG. Four points at the edge of the finger (P in FIG. 16)
1 to P4). These four points are all different from the designated center point (Pc in FIG. 16).
Therefore, the coordinates of the center point Pc (Pc
x, Pcy). 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, θ1 expressed by the equations (3) and (4)
By substituting + dθ / 2, φ1 + dφ / 2 as θ, φ in the above equations (1) and (2), the designated center point P
The coordinates of c can be obtained.

In the example described above, first, the average value of the angle is obtained, and the average value of the angle is substituted into the conversion formulas (1) and (2) of the triangulation to obtain the center point Pc which is the designated position.
First, the orthogonal coordinates of the four points P1 to P4 are obtained from the scanning angles according to the conversion formulas (1) and (2) of the triangulation, and the average of the obtained coordinate values of the four points is calculated. Thus, the coordinates of the center point Pc can be determined. In addition, it is also possible to determine the coordinates of the center point Pc, which is the designated position, in consideration of the parallax and the visibility of the designated position.

When the scanning angular velocity of each polygon mirror 15 is constant, information on the scanning angle can be obtained by measuring the time. FIG. 17 is a timing chart showing the relationship between the light receiving signal from the light receiving signal detection circuit 3a and the scanning angle θ and the scanning time T of the polygon mirror 15 in the optical unit 1a. If the scanning angular velocity of the polygon mirror 15 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 (5). θ = ω × T (5)

Therefore, the angles θ1 and θ2 at the time of falling and rising of the light receiving signal are respectively set to the scanning times t1 and t2.
2 and the following equations (6) and (7) hold. θ1 = ω × t1 (6) θ2 = ω × t2 (7)

Therefore, when the scanning angular velocity of the polygon mirror 15 is constant, the pointer S is determined using the time information.
It is possible to measure the cutoff range and coordinate position of the (finger).

In the optical scanning type touch panel of the present invention, the size (cross-sectional length) of the pointer S (finger) can be obtained from the measured blocking range. FIG. 18 is a schematic diagram showing the principle of this cross-section length measurement. In FIG. 18, D
Reference numerals 1 and D2 denote cross-sectional lengths of the pointer S viewed from the optical units 1a and 1b, respectively. First, the optical units 1a and 1b
, Distances OPc (r1) from the positions O (0,0), B (L, 0) to the center point Pc (Pcx, Pcy) of the pointer S
BPc (r2) is obtained as in the following 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 section length can be approximated by the product of the distance and the sine value of the cutoff angle, the section lengths D1 and D2 are given by the following (1).
It can be measured according to equations (0) and (11). D1 = r1 · 2sin θ / 2 = (Pcx ² + Pcy ² ) ^1/2 · 2sin θ / 2 (10) D2 = r2.2sinφ / 2 = ｛(L−Pcx) ² + Pcy ² ｝ ^1/2 · sinφ / 2 … (11)

If θ, φ ≒ 0, sin
dθ ≒ dθ ≒ tan θ, sinφ ≒ dφ ≒ tand
Since it can be approximated to φ, s in equations (10) and (11)
Instead of indθ and sinφ, dθ or tan
θ, dφ or tanφ may be used.

[0056]

As described above, according to the present invention, a plurality of light retroreflectors having different light retroreflection characteristics are combined. It is possible to improve the S / N ratio for detecting the position of the pointer.

Further, since the incident angle to the light retroreflector is set to substantially 0 degree in a region where the incident angle in the light scanning is large, even if the incident angle is originally in the region where the incident angle is large, the incident angle is reduced. When it is small, it is possible to provide a light retroreflector having the strongest light retroreflection characteristics, and it is possible to improve the S / N ratio for detecting the position of the pointer.

Further, since the protective material for protecting the light retroreflector is provided, it is possible to protect the light retroreflector from moisture, dust and the like.

Further, since the surface of the protective material is subjected to the anti-reflection treatment, the decrease in the amount of light due to the reflection on the surface of the protective material is suppressed, and the S / N ratio for detecting the position of the pointer is improved. It is possible.

In addition, since the light reflection preventing treatment of the protective material is optimized for an arbitrary incident angle on the light retroreflector, a reduction in the amount of light due to reflection on the surface of the protective material is suppressed. Thus, it is possible to improve the S / N ratio for detecting the position of the pointer.

Since the protective member has a deflecting function of changing the direction of light, the protective member adjusts the incident angle with respect to the light retroreflector to detect the position of the pointer.
It is possible to improve the / N ratio.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a basic configuration of an optical scanning type touch panel of the present invention.

FIG. 2 is a perspective view showing a configuration and an optical path of an optical system in the optical unit.

FIG. 3 is a schematic diagram showing a configuration of a main part of the optical scanning touch panel of the present invention.

FIG. 4 is a graph showing light retroreflection characteristics of two types of retroreflective sheets.

FIG. 5 is an enlarged view of a boundary portion between two types of retroreflective sheets.

FIG. 6 is an enlarged view of a boundary portion between two types of retroreflective sheets.

FIG. 7 is a schematic diagram showing a configuration of a main part of another optical scanning type touch panel of the present invention.

FIG. 8 is a sectional view showing a configuration of a main part of another optical scanning type touch panel of the present invention.

FIG. 9 is a cross-sectional view illustrating a reflection prevention process of the protective cover.

FIG. 10 is a schematic diagram showing a configuration of a main part of still another optical scanning type touch panel of the present invention.

FIG. 11 is a partially enlarged view of FIG. 10;

FIG. 12 is a schematic diagram showing a configuration of a main part of still another optical scanning type touch panel of the present invention.

FIG. 13 is a partially enlarged sectional view of FIG.

FIG. 14 is a schematic diagram showing an implementation state of an optical scanning touch panel.

FIG. 15 is a schematic diagram showing the principle of triangulation for coordinate detection.

FIG. 16 is a schematic diagram showing an indicator and a cutoff range.

FIG. 17 is a timing chart showing a relationship between a light receiving signal, a scanning angle, and a scanning time.

FIG. 18 is a schematic diagram showing the principle of measuring the cross-sectional length.

[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 Housing 10 Display screen (coordinate plane) 11 Light emitting element 13 Light receiving element 15 Polygon Mirror 21 Protective cover 22 Anti-reflection film 23 Supporting material 24 Protective cover with deflection function S Indicator

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Fumihiko Nakazawa 4-1-1, Kamikodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Nobuyasu Yamaguchi 4-1-1 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture No. 1 Fujitsu Limited F term (reference) 2H089 HA40 JA10 QA16 TA16 TA17 TA18 UA09 2H093 NC50 NC53 NC72 ND60 NE06 5B068 AA04 AA22 AA33 BB20 BC04 5B087 AA02 AC15 CC02 CC03 CC05 CC09 CC12 CC15 CC34

Claims (6)

[Claims] A light retroreflector provided outside a predetermined area; an optical scanning unit for angularly scanning light in a plane substantially parallel to the predetermined area; A plurality of optical units each having a light receiving unit for receiving light reflected by the light retroreflector, wherein a light blocking position of the scanning light formed by the pointer in the predetermined area corresponds to a scanning angle. An optical scanning type touch panel for detecting based on an output, wherein the optical retroreflector is configured by combining a plurality of optical retroreflectors having different optical retroreflection characteristics. . 2. A light retroreflector provided outside a predetermined area, an optical scanning section for angularly scanning light in a plane substantially parallel to the predetermined area, and a light scanning section for scanning light by the optical scanning section. A plurality of optical units each having a light receiving unit for receiving light reflected by the light retroreflector, wherein a light blocking position of the scanning light formed by the pointer in the predetermined area corresponds to a scanning angle. In an optical scanning type touch panel that detects based on an output, a part of the light retroreflector has an incident surface inclined so that an incident angle of the scanning light becomes substantially 0 degrees. Optical scanning type touch panel. 3. The optical scanning type touch panel according to claim 1, wherein a protective material for protecting the light retroreflector is provided on a surface of the light retroreflector. 4. The optical scanning type touch panel according to claim 3, wherein a light reflection preventing treatment is applied to a surface of said protective material. 5. The light-scanning touch panel according to claim 4, wherein an anti-reflection treatment of the protective material is optimized for an arbitrary incident angle of the scanning light on the light retroreflector. 6. The optical scanning type touch panel according to claim 3, wherein the protection member has a deflection function of changing a direction of the scanning light.