JP3931030B2 - Position detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light-blocking optical digitizer that detects the pointing position coordinates of a pointer on a detection surface. In particular, the present invention relates to an optical digitizer having a reduced height at which it is detected that an indicator touches a detection surface.
[0002]
[Prior art]
In place of the resistive film type or electromagnetic induction type digitizer, an optical type digitizer having a more accurate detection capability has attracted attention. FIG. 5 shows an example of an optical digitizer using a linear image sensor. FIG. 5A is a schematic plan view of the optical digitizer. FIG.5 (b) is the side view of the partial cross section. As shown in the figure, when a pen 2 as an indicator is placed on the detection surface 1, the indicated position coordinates are detected by the principle of triangulation by two detection units 3 provided above the detection surface 1. is there. Each of the two detection units 3, as shown in FIG. 5 (b), has a configuration of arranging the LED light source 11 on the imaging lens 9 of the linear image sensor 13. When nothing is blocking the light on the detection surface 1, the light that has passed through the detection surface 1 and entered the retroreflective member 22 from the detection unit 3 passes through the reverse optical path to the detection unit 3. Come back. When the pen 2 or the like is placed on the detection surface 1, a part of the optical path of the light is blocked, and the detection unit 3 cannot be returned. Since this shadow portion can be imaged by the image sensor 13, the direction of the shadow is detected by the two detection units 3 and 3 , so that the direction in which the light is blocked can be detected. That is, if the direction in which the pen 2 exists can be detected by the detection units 3 and 3 at two different known positions, the indicated position coordinates of the pen 2 can be calculated by the principle of triangulation.
[0003]
[Problems to be solved by the invention]
However, in the example shown in FIG. 5, as shown in FIG. 6, the detection surface of the optical path of the outgoing light radiated from the light source 11 toward the detection surface 1 and the optical path of the return light reflected from the retroreflective member 22. LED light sources 11 before the pen touches the detection surface (with the pen floating) because the heights of the light sources are not matched and in particular the outgoing optical path is far away from the detection surface 1. Touch detection is performed at the time when the light beam emitted from the light and directed toward the retroreflective member 22 is blocked. For this reason, there is a problem that when a character such as a kanji is written with a pen, the character continues. Further, in the touch operation with a finger, touch detection is performed even when there is no actual touch on the detection surface, so that the operability is poor.
[0004]
In view of such circumstances, an object of the present invention is to provide an optical digitizer capable of performing touch detection near a detection surface.
[0005]
[Means for Solving the Problems]
In order to solve such a problem, a position detection device according to the present invention has a rectangular detection surface provided with retroreflective members on three sides excluding one side, and an indicator positioned on the detection surface. A light source that emits a light beam toward the detection surface at each end of the one side of the detection surface, an imaging unit that receives the retroreflected light from the retroreflective member, and the imaging unit to detect the designated position coordinates An imaging lens that forms an image of the retroreflected light provided on the front surface of the lens, and a shadow generated by the indicator located on the detection surface blocking the optical path is detected by each of the imaging means, and triangulation In the position detection device that calculates the coordinate position of the indicator according to the principle of
In the vicinity of the left and right sides of the imaging lens, the light beam emitted from the light source is located at a position where the height of the light beam emitted from the light source and the return light beam reflected by the retroreflective member from the detection surface is the same. Mirror means for bending a light beam toward the detection surface is provided.
[0006]
Further, the mirror means is a curved mirror, and may have a function of condensing or diffusing the light beam of the light source. The light source may be provided at the left and right positions of the imaging lens and the curved mirror, and emit light toward the curved mirror from a direction approximately parallel to the detection surface.
[0007]
A position detection device according to another aspect of the present invention has a rectangular detection surface provided with retroreflective members on three sides excluding one side, and the indication position coordinates of the indicator located on the detection surface are obtained. In order to detect, a light source that irradiates light toward the detection surface at both ends of the one side of the detection surface, an imaging unit that receives retroreflected light from the retroreflective member, and a front surface of the imaging unit And an imaging lens for imaging the retroreflected light, and a shadow generated by the indicator located on the detection surface blocking the optical path is detected by each imaging means, and based on the principle of triangulation In the position detection device that calculates the coordinate position of the indicator,
The light receiving surface of the imaging means is arranged in a direction perpendicular to the direction of the detection surface,
A mirror that folds the imaging field of the imaging means at a position in the vicinity of the light source where the outgoing light beam emitted from the light source and the return light beam reflected by the retroreflective member have the same height from the detection surface. Means are provided.
[0008]
The mirror means may be configured as a part of a lens member of the imaging lens.
[00 09 ]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Parts denoted by the same reference numerals as those used in the drawings represent the same thing.
[00 10 ]
FIG. 1 is a diagram showing a preferred embodiment of an optical digitizer that detects the coordinate position of an indicator based on the triangulation principle of the present invention. In order to solve the above problem, the inventor of the present invention needs to make the difference between the angle of the light beam emitted from the light source toward the detection surface and the angle at which the retroreflected light beam enters the linear image sensor as small as possible. I noticed. However, if the light source is arranged beside the imaging lens, the light source hits the lens, the image sensor, or the optical path therebetween. As a result of careful consideration, it is effective to bend the light beam with a mirror means in order to further reduce the opening of the angle between the two light beams rather than limiting the size of the light source (light emitting diode) or the member of the linear image sensor. I came up with the idea shown in Fig. 1.
[00 11 ]
FIG. 1A shows a linear image sensor 13, an imaging lens 9, and a light source (light emitting diode) 11 inside a detection unit 3 provided on the left and right sides of one side of the detection surface, which are the main parts of the position detection device of the present invention. 4 is a view of the positional relationship of the mirror 12 as viewed from the side. FIG. 1B shows the positional relationship among the linear image sensor 13, the imaging lens 9, the light source (light emitting diode) 11, and the mirror 12 in the detection unit 3, which is the main part of the position detection apparatus of the present invention, and the light beam traveling direction. It is the figure seen from (the direction which looks at the linear image sensor 13 from the position of the pen 2). As shown in the figure, by arranging the light source downward and bending the traveling direction thereof by the mirror 12 by approximately 90 degrees, the height from the detection surface of the outgoing and the return of the light beam can be made the same. Moreover, as shown in FIG. 1B, the mirror 12 can be disposed in the immediate vicinity of the imaging lens 9. The retroreflective member 22 shown in FIG. 5 and FIG. 6 is a member having a function of returning a light beam in the same direction as the direction of the light beam. Is reduced to about 1/10. As shown in FIG. 1, by arranging the mirror 12 in the immediate vicinity of the imaging lens 9, the optical paths for going and returning are well aligned, and in combination with the provision of two light sources 11, a sufficient signal can be obtained. Strength can be obtained.
[00 12 ]
FIG. 1C is a diagram illustrating an example in which the mirror in the embodiment is changed to a cylindrical concave mirror. In FIG. 1A, the mirror is a plane mirror. However, the mirror may be a cylindrical curved mirror so that the light rays of a wide light source are condensed in the vertical direction to form a beam parallel to the detection surface. Thus, by using a curved mirror as the mirror, it is possible to efficiently use the light beam of the light source for touch detection and coordinate detection of the indicator. Here, the cylindrical curved mirror refers to a mirror having a cylindrical curved surface.
[00 13 ]
【Example】
Next, an embodiment of the present invention will be described with reference to FIG. FIG. 2 is a diagram showing an embodiment in which light sources are arranged on the left and right using cylindrical mirrors. This figure is a plan view, and the inside of the detection unit 3 is viewed from above. Cylindrical concave mirrors 25 are arranged on both the left and right sides of the imaging lens 9, and the light source 11 is arranged on both sides as shown in the figure. A linear image sensor 13 is placed at a position connecting the images of the imaging lens. With this configuration, the light from the light source is emitted at the same height (or almost the same height) as the height of the light beam incident on the linear image sensor 13 (height from the detection surface 1 for detecting the position of the pen 2). It is possible to cast on the position detection surface.
[00 14 ]
FIG. 3 is a diagram showing an embodiment in which linear image sensors are arranged downward. 3A shows the light beam from the side, and FIG. 3B shows the light beam from the traveling direction. In this embodiment, the light source 11 emits a light beam directly toward the detection surface without being bent. The linear image sensor 13 has a light receiving surface disposed downward. The retroreflected light beam from the retroreflective member 22 provided around the detection surface 1 is bent by approximately 90 degrees by the mirror 12 and enters the linear image sensor 13. Also in this embodiment, the height of the two light beams from the detection surface can be made substantially the same.
[00 15 ]
FIG. 4 is a diagram showing an embodiment in which the imaging lens and the mirror member are configured by one optical member. This embodiment is a modified embodiment of the embodiment in which the linear image sensor shown in FIG. When the linear image sensor is arranged downward, the light incident on the linear image sensor is bent by the light beam bending means (mirror means), and immediately after that, is refracted by the imaging lens. The inventor of the present invention thought that the mechanism of the detection unit of the present invention can be further simplified by configuring the mirror and the lens as an integral optical member. FIG. 4A is a view of this embodiment as viewed from the side, and FIG. 4B is a view of the embodiment as viewed from the traveling direction of the light beam. A feature of the present invention is that an imaging lens 19 with a mirror is provided instead of the mirror 12 and the imaging lens 9 shown in FIG.
[00 16 ]
FIG. 7 shows a manufacturing method of the imaging lens with a mirror. FIG. 7A is a diagram of the convex lens viewed from the traveling direction of the light beam, and FIG. 7B is a diagram of the convex lens viewed from the side. This convex lens has a spherical surface on one side and a flat surface on the other side. As shown in the figure, this lens is cut into three parts 41, 42, and 43, and 41 and 43 are discarded, and 42 is taken out and used. Further, the end portion on the plane side is cut at an angle of 45 degrees as shown in FIG. The image forming lens 19 with a mirror shown in FIG. Since the surface cut at 45 degrees is totally reflected on the same principle as a prism, it functions as a mirror. In addition, in order to explain the configuration of the imaging lens 19 in an easy-to-understand manner, this manufacturing method has been shown.
[00 17 ]
The optical digitizer of the present invention is not limited to the illustrated examples described above, and it is needless to say that various modifications can be made without departing from the scope of the present invention. For example, an optical digitizer having a large detection surface can be realized by realizing the left and right light sources as a set of a plurality of LEDs. This is an effect that can be realized by the present invention by relaxing restrictions on the space of the light source.
[00 18 ]
【The invention's effect】
As described above, according to the optical digitizer of the present invention, since it is possible to provide an optical digitizer capable of performing touch detection near the detection surface, it is possible to accurately detect whether the pen tip has touched or moved away from the detection surface. Therefore, an optical digitizer suitable for character recognition can be provided. Further, even in a touch operation with a finger, since the operator's actual feeling that the finger touches the detection surface coincides with the touch detection of the apparatus, an excellent effect that an optical digitizer with good operability can be provided can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of an optical digitizer according to the present invention.
FIG. 2 is a diagram showing an embodiment in which light sources are arranged on the left and right sides using cylindrical mirrors.
FIG. 3 is a diagram showing an embodiment in which linear image sensors are arranged downward.
FIG. 4 is a diagram illustrating an embodiment in which an imaging lens and a mirror member are configured by one optical member.
FIG. 5 is a diagram showing an optical digitizer using a linear image sensor.
FIG. 6 is a diagram illustrating a problem of an optical digitizer using a linear image sensor.
FIG. 7 is a diagram for explaining a method of manufacturing an imaging lens and a mirror member when the optical lens and the mirror member are constituted by one optical member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Detection surface 2 Pen 3 Detection unit 9 Imaging lens 11 Light source (light emitting diode, LED)
12 Mirror 13 Linear Image Sensor 19 Imaging Lens 22 with Mirror Retroreflective members 24 and 25 Cylindrical concave mirror

Claims (5)

A rectangular detection surface provided with retroreflective members on three sides excluding one side, and both end portions of the one side of the detection surface to detect the indicated position coordinates of the indicator located on the detection surface the respective positions slightly upward from the detection surface a is a light source that emits toward Cow beam to the retroreflective member provided to the two sides passes over the detection plane intersecting at a right angle of the detection surface, the recursive An indicator located on the detection surface, having an imaging unit comprising an image sensor that receives retroreflected light from a reflecting member, and an imaging lens that is provided in front of the imaging unit and forms an image of the retroreflected light In the position detection device that detects the shadow caused by blocking the optical path by each imaging means, and calculates the coordinate position of the indicator according to the principle of triangulation,
In the vicinity of the left and right sides of the imaging lens, the height of the outgoing light beam emitted from the light source provided sideways with respect to the detection surface and the return light beam reflected by the retroreflective member from the detection surface are the same. A position detecting device, comprising: mirror means for bending most of the light rays emitted from the light source toward the retroreflective member at a position where The position detection device according to claim 1,
The position detecting device, wherein the mirror means is a curved mirror and has a function of condensing or diffusing the light beam of the light source. The position detection device according to claim 2,
The light source is provided at the left and right positions of the imaging lens and the curved mirror, and emits light toward the curved mirror from a direction approximately parallel to the detection surface. A rectangular detection surface provided with retroreflective members on three sides excluding one side, and both end portions of the one side of the detection surface to detect the indicated position coordinates of the indicator located on the detection surface A light source that emits a light beam directed to the retroreflective member provided on two sides passing through the detection surface and intersecting at right angles to the detection surface at respective positions slightly above the detection surface, and the retroreflection An indicator located on the detection surface, the imaging means including an image sensor configured to receive retroreflected light from a member, and an imaging lens provided on a front surface of the imaging means for imaging the retroreflected light; In the position detection device that detects the shadow caused by blocking the optical path by each imaging means, and calculates the coordinate position of the indicator according to the principle of triangulation,
In the vicinity of the left and right sides of the imaging lens, the height of the outgoing light beam emitted from the light source provided downward with respect to the detection surface and the return light beam reflected by the retroreflective member from the detection surface are the same. A position detecting device, comprising: mirror means for bending most of the light rays emitted from the light source toward the retroreflective member at a position where The position detection device according to claim 4,
The position detecting device, wherein the mirror means is a curved mirror and has a function of condensing or diffusing the light beam of the light source.

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