Optical position detection device and display system with input function
In an optical position detection device, when emitting the detection light from the light source section, the light receiving section receives the reflected light from the target object with the first light receiving element and the second light receiving element. The first light receiving element and the second light receiving element are arranged to have the intersection angle greater than 90° and smaller than 180°, the intersection angle being formed between the normal direction with respect to the light receiving surface of the first light receiving element and the normal direction with respect to the light receiving surface of the second light receiving element.
1. An optical position detection device comprising:
a light source device adapted to emit detection light, and to vary emission intensity of the detection light from one side of a space where the detection light is emitted toward the other side when emitting the detection light;
a light receiving section adapted to receive the detection light reflected in the space; and
a position detection section adapted to detect a position of a target object in the space based on a detecting signal output from the light receiving section,
wherein the light receiving section includes a first light receiving element having a light receiving surface pointed at the one side of the space and a second light receiving element having a light receiving surface pointed at the other side of the space at a position adjacent to the first light receiving element,
an intersection angle between a normal direction with respect to the light receiving surface of the first light receiving element and a normal direction with respect to the light receiving surface of the second light receiving element is larger than 90° and smaller than 180°,
the light source device reduces the emission intensity from the one side of the space toward the other side in a first period, and reduces the emission intensity from the other side of the space toward the one side in a second period having no overlap with the first period,
the position detection section detects the position of the target object based on a drive current value in the light source device when a level of the detecting signal in the first period and a level of the detecting signal in the second period become equal to each other,
the position detection section varies the drive current value in the first period and the drive current value in the second period based on a result of comparison between a level of the detecting signal in the first period and a level of the detecting signal in the second period when the light source device emits the detection light using a reference drive current value in the first period and the second period, and
when the level of the detecting signal in the first period and the level of the detecting signal in the second period become equal to each other, the position of the target object is detected based on a comparison result between an adjustment amount of the drive current value in the first period from the reference drive current value and an adjustment amount of the drive current value in the second period from the reference drive current value.
2. The optical position detection device according to claim 1 , wherein
the intersection angle is larger than 120° and smaller than 140°.
3. The optical position detection device according to claim 1 , wherein
the first light receiving element and the second light receiving element simultaneously detect the detection light reflected in the space.
4. The optical position detection device according to claim 1 , wherein
the first light receiving element and the second light receiving element detect the detection light reflected in the space in respective periods different from each other.
5. The optical position detection device according to claim 4 , wherein
the light source device sets the reference drive current value in the first period to be lower than the reference drive current value in the second period in a period in which the first light receiving element performs the detection, and sets the reference drive current value in the second period to be lower than the reference drive current value in the first period in a period in which the second light receiving element performs the detection.
6. The optical position detection device according to claim 5 , wherein
the light source device includes
a first light source adapted to emit the detection light in the first period,
a first amplification section adapted to amplify a current to be supplied to the first light source,
a second light source adapted to emit the detection light in the second period, and
a second amplification section adapted to amplify a current to be supplied to the second light source.
7. A display system with an input function comprising:
the optical position detection device according to claim 1 ; and
a display device provided with a display surface where an image is displayed,
wherein the display device switches the image based on the position of the target object in a direction along the display surface detected by the optical position detection device.
8. A display system with an input function comprising:
the optical position detection device according to claim 2 ; and
a display device provided with a display surface where an image is displayed,
wherein the display device switches the image based on the position of the target object in a direction along the display surface detected by the optical position detection device.
9. A display system with an input function comprising:
the optical position detection device according to claim 3 ; and
a display device provided with a display surface where an image is displayed,
wherein the display device switches the image based on the position of the target object in a direction along the display surface detected by the optical position detection device.
10. A display system with an input function comprising:
the optical position detection device according to claim 4 ; and
a display device provided with a display surface where an image is displayed,
wherein the display device switches the image based on the position of the target object in a direction along the display surface detected by the optical position detection device.
11. A display system with an input function comprising:
the optical position detection device according to claim 1 ; and
an image projection device adapted to project an image,
wherein the image projection device switches the image based on the position of the target object in a direction traversing a projection direction of the image detected by the optical position detection device.
12. A display system with an input function comprising:
the optical position detection device according to claim 2 ; and
an image projection device adapted to project an image,
wherein the image projection device switches the image based on the position of the target object in a direction traversing a projection direction of the image detected by the optical position detection device.
13. A display system with an input function comprising:
the optical position detection device according to claim 3 ; and
an image projection device adapted to project an image,
wherein the image projection device switches the image based on the position of the target object in a direction traversing a projection direction of the image detected by the optical position detection device.
14. A display system with an input function comprising:
the optical position detection device according to claim 4 ; and
an image projection device adapted to project an image,
wherein the image projection device switches the image based on the position of the target object in a direction traversing a projection direction of the image detected by the optical position detection device.