JPS61122738A - Optical coordinate input device - Google Patents

Abstract

PURPOSE:To prevent the titled device from detection of light other than that irradiated by a light pen by arranging a filter having a light emitting body absorbing area between a picture display device and an optical waveguide. CONSTITUTION:The filter 6 is arranged between the optical waveguide 6 and the display 2. Light having wavelength less than about 600nm out of that emitted from a picture element 12 on the display 2 is absorbed by the filter 16, a fluorescent substance 14 is not emitted and a photodetecting means 10 decides only the position irradiated by the light pen 4.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is based on the coordinate position t that is superimposed on the screen of a display device such as a personal computer and that is input by Oberley in order to select information such as a menu displayed on the display.
This invention relates to an optical coordinate input device for t-detection.

[Prior art]

The applicant has already added a material, such as coumarin 6 (C6) (manufactured by Wako Pure Chemical Industries, Ltd.) phosphor, to a light guide path having a light detection means, which has a few wavelengths in common with the wavelength of the light emitting region and the wavelength of the absorption region. We have proposed a light guide type optical coordinate human-powered device f that incorporates light as a light emitter.

This type of optical coordinate input device is used to record coordinate positions input by an operator in order to select information such as a menu displayed on the display. It is often used for detection.

FIG. 5 is a cross-sectional view of the optical coordinate input device provided over the display. As shown in the figure, when a predetermined position on the display 2 as an image display device is illuminated with a light source 4, the display becomes visible. A fluorescent body 8 in a light guide path 6 provided on the light guide path 6 emits light, and the fluorescent light propagates through the light guide path 6 and is detected by the light detecting means 10 to determine the irradiation position of the light pen 4.

FIG. 2 is a graph showing the light emission characteristics of the pixels 12 on DisGray 2. The vertical axis represents relative radiant energy and the horizontal axis represents wavelength (nm).

FIG. 3 is a graph showing the absorption characteristics of coumarin 6, which is the phosphor 8.

As shown in FIGS. 2 and 3, the graph of the emission characteristics of the display 20 and the graph of the absorption characteristics of coumarin 6 are shown at a wavelength of 350.
There is an overlapping portion between 600 nm and 600 nm.

By the way, the entire surface of the display 2 is illuminated, and when a pixel 12 on the display 2 that is different from the position irradiated by the light pen 4 emits light, the light emitting characteristics of the display 2 (FIG. 2) and the absorption characteristics of the silicon principal 14 are determined as described above. (FIG. 3) has an overlapping portion in the wavelength range of 350 to 600 nm, so the silicon element 14 receives the light emitted by the pixel 12 and emits light itself, which is detected by the photodetector 10. However, the light detection means also detects the light emitted from the silicon main body 14 located at a position other than the position irradiated by the light pen 4, resulting in a problem that the detection accuracy of such an optical coordinate input device is reduced.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a light guide type optical coordinate input device that is simple and has high detection accuracy in order to eliminate the above-mentioned drawbacks.

〔composition〕

In order to achieve the above object, the present invention provides a filter having an absorption region including the absorption region of the light emitter between the image display device and the light guide, and absorbs the absorption region of the light emitter out of the light emitted from the image display device. It is characterized by a filter absorbing light with a certain wavelength.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a side view of a light guide type optical coordinate input device according to an embodiment of the present invention, and the elements that perform the same functions as the conventional optical coordinate input device shown in FIG. A code is attached. In this embodiment, a filter 16 having absorption characteristics shown in FIG. 4 is provided between the light guide path 6 and the display 2.

As shown in FIGS. 3 and 4, the absorption characteristics of the phosphors 8 and 14 and the absorption characteristics of the filter 16 overlap at wavelengths of about 600 nm or less.

By the way, the light emitted from the pixel 12 of the display 2 having the light emitting characteristics shown in FIG. However, since the light has a wavelength of 600 nm or more, the phosphor does not emit light. This is because the phosphor 14 does not absorb light with a wavelength of 600 nm or more.

Therefore, the silicon element 14 does not emit light due to the light emitted from the pixel 12.

〔effect〕

As explained above in detail and concretely, a filter having an absorption region including the absorption region of the light emitter is provided between the image display device and the light guide, and the absorption region of the light emitter out of the light emitted from the image display device is provided. By absorbing light of a certain wavelength by a filter, the optical coordinate reading device according to the present invention can perform highly accurate coordinate reading.

[Brief explanation of drawings]

Fig. 1 is a side view of the light guide type optical coordinate input device according to this embodiment, Fig. 2 is a graph showing the light emission characteristics of a display gray device such as a CRT, and Fig. 3 is a graph showing the absorption characteristics of the phosphor. Figure 4 is a graph showing the absorption characteristics of the filter, and Figure 5 is a side view of a conventional light guide type optical coordinate input device.

Claims (1)

[Claims] (1) A light guide path provided on the image display device and having a light detection means is arranged in parallel, and a light emitting body is included in the light guide path,
When a predetermined position on the image display device is irradiated with a light source,
In an optical coordinate input device in which the light emitting body emits light and the light detecting means detects the light to detect the input position of the light source on the image display device; providing a filter having an absorption region that includes an absorption region of the light emitter;
An optical coordinate input device characterized in that, of the light emitted from the image display device, light having a wavelength in an absorption region of the light emitter is absorbed by the filter.