1. Technical Field
The present invention relates to an optical position detection device which detects a target object optically.
2. Related Art
There are various kinds of optical position detection devices which detect a target object optically. Among such various kinds of optical position detection devices, a device configured to include two light source sections for detection and one light detecting section is disclosed in JP-T-2003-534554. As shown in FIG. 8, JP-T-2003-534554 proposes that detection light L2 is emitted from two light source sections for detection 12 toward a target object Ob through a light transmissive member 40 and detection light reflected from the target object Ob is transmitted through the light transmissive member 40 and is then detected by a light detecting section 30, for example. In the optical position detection device, the relationship of the distance between one of the two light source sections for detection 12 and the target object Ob and the distance between the other light source section for detection 12 and the target object Ob can be seen if the two light source sections for detection 12 are driven so that the difference therebetween is obtained on the basis of a detection result of the light detecting section 30, for example. Therefore, the position of the target object Ob can be detected.
In the configuration shown in FIG. 8, however, there is a problem in that the relationship of the distance between one of the two light source sections for detection 12 and the target object Ob and the distance between the other light source section for detection 12 and the target object Ob becomes the same when the target object Ob shown as a target object Ob1 is located inside a region between the two light source sections for detection 12 and when the target object Ob shown as a target object Ob2 is located outside the region between the two light source sections for detection 12. For this reason, when calculating the relationship of the distance between one of the two light source sections for detection 12 and the target object Ob and the distance between the other light source section for detection 12 and the target object Ob, it is not possible to determine whether the distance between the two light source sections for detection 12 is to be internally divided or externally divided.