JPH0421122B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an incident position detection device for a light spot or the like for detecting the incident position of radiation by a light spot.

[Prior Art] Conventionally, image pickup tubes and CCDs (charge-coupled devices) have been known as two-dimensional detection devices for detecting the incident position of light spots, etc., but both are expensive and require processing circuits. It's complicated.

The applicant has already stated in Japanese Patent Application No. 60-274499,
We have proposed a device that detects the incident position of a plate containing a secondary light emitter, but in this case one-dimensional or multiple photoelectric conversion elements are required.

[Object of the Invention] An object of the present invention is to provide an incident position detection device for a light spot, etc., which can detect the incident position of a light spot, etc., with a simpler configuration.

[Summary of the invention] The gist of the present invention for achieving the above object is as follows:
A transparent or translucent strip member also containing a secondary luminescent material or a scattering material is disposed in close contact with the end face of a transparent or translucent plate containing a secondary luminous material or a scattering material, and A photoelectric conversion element is arranged at at least one end of the strip member, a light spot or radiation is made incident on the surface of the plate member, and secondary light or scattered light generated within the plate member is guided to the strip member. This is an incident position detection device for a light spot or the like, characterized in that it generates two-dimensional or scattered light again and detects the incident position of the light spot or radiation from the light intensity obtained by the photoelectric conversion element.

[Embodiments of the Invention] The present invention will be described in detail based on illustrated embodiments.

In FIG. 1, reference numeral 1 is a transparent or translucent plate made of, for example, synthetic resin and containing a fluorescent agent.
Strip members 2a to 2d made of transparent or translucent synthetic resin and containing a fluorescent agent are closely attached to each end surface 1a to 1d of the plate 1. and,
At the ends of these strip members 2a to 2d, photoelectric conversion elements 3a, 3a', 3 made of, for example, solar cells are installed.
b, 3b',..., 3d' are attached respectively, and these photoelectric conversion elements 3a, 3a', 3b, 3
The outputs of b', . . . , 3d' are input to an arithmetic processing circuit (not shown).

Here, when the light spot S is incident on the surface of the plate 1, the fluorescent agent in the plate 1 is excited by the light spot S and emits fluorescence in random directions, and this fluorescence propagates through the plate 1. and reaches each end face 1a to 1d. In this case, the fluorescence is attenuated while propagating through the plate 1, and the light intensity at each position of each end face 1a to 1d monotonically increases or decreases depending on the distance to the light spot S. The fluorescence emitted from the end faces 1a to 1d enters the strip members 2a to 2d, respectively, and is emitted again in a random direction by the fluorescent agent contained in the strip members 2a to 2d. propagates and enters the photoelectric conversion elements 3a, 3a', . . . , 3d' arranged at both ends thereof.

In this case, the fluorescent agent absorbs light in a wavelength band centered on about 500 nm and emits light in a wavelength band centered on about 600 nm, and the light in the wavelength band emitted from the plate 1 The strip member 2a~
It is desirable that the fluorescent agent 2d is in an absorbing relationship. Therefore, it is preferable that the fluorescent agent contained in the plate 1 and the fluorescent agent contained in the strip members 2a to 2d be of different types.

In order to find the position of the light spot S in the X direction in FIG.
The ratio of output from the ends of photoelectric conversion elements 3a and 3a', for example, the sum of the outputs of photoelectric conversion elements 3a and 3a', and the output of photoelectric conversion element 3c
By determining the ratio of the sum of the outputs of and 3c', the position of the light spot S on the surface of the plate 1 in the X direction can be determined regardless of the amount of incident light.

That is, if the length of the side of the plate 1 is D, and the shortest distance from the light spot S to the end surface 1a is x, then the photoelectric conversion elements 3a, 3a',
Output based on fluorescence light intensity obtained at 3c and 3c'
Pa and Pc are respectively Pa=K/f(x) Pc=K/{D-f(x)}. Here, K is the light intensity and size of the light spot S, the light conversion efficiency of the fluorescent agent, the plate 1, the strip member 2
is a constant that depends on the fluorescence decay rate in At this time, calculate the sum Pa + Pc and the difference Pa - Pc of the outputs of both photoelectric conversion elements 3a, 3a', 3c, 3c', and
If Pa−Pc is divided by the sum Pa+Pc, f(x)
=Pc·D/(Pa+Pc), and since the characteristics of f(x) can be determined in advance, it is possible to determine the distance x without depending on the light intensity of the light spot S, etc.

Note that the output characteristics from the end face of the plate 1 in this case are as shown in FIG.
There is a tendency for the output to be larger as the position is closer to the center of the area. On the other hand, when the fluorescence incident on the strip member 2 with the same amount of light is detected by the photoelectric conversion elements 3 at both ends and the sum is calculated, as shown in Figure 2b, the amount of light incident on the center part is reduced due to the attenuation of the light amount. The smaller it becomes. Therefore, both curves eventually cancel each other out, and the outputs obtained from the photoelectric conversion elements 3 at both ends become almost flat as shown in FIG. 2c.

Also, in the Y direction, two strip members 2b,
Photoelectric conversion elements 3b, 3b', 3 provided on the end face of 2d
The position of the light spot S can be similarly determined from the outputs of d and 3d', and it is possible to detect the two-dimensional position of the light spot S together with the X direction.

In FIG. 1, the light spot S on the plate 1 is
The position of
The position of the light spot S in the Y direction can be determined by the ratio of the outputs of 3c' and 3c'.

As mentioned above, the wavelength of the excited fluorescence varies depending on the wavelength of the incident light on the light spot S or the type of fluorescent material, but a filter that transmits only the excitation light of the fluorescent material contained in the strip member 2 is used. If it is provided in front of each photoelectric conversion element 3a, 3a', . Of course, it is desirable to expose only the surface of the plate 1 and block the rest from external light, but if it is not possible to form a complete dark box, the incident light of the light spot S is modulated and synchronized with this modulated light. The influence of external light may be removed by detecting only the outputs from the photoelectric conversion elements 3a, 3a', 3b, 3b', . . . , 3d'.

Further, in FIG. 3, only the two orthogonal end surfaces 1a and 1b of the plate 1 have strip members 2a and 1b, respectively.
2b is arranged, and light spots S are emitted from photoelectric conversion elements 3a, 3a', 3b, 3b' provided at the ends
I am trying to find the position of. Furthermore, although the photoelectric conversion elements 3 are provided at both ends of the strip member 2, measurements can be made even if the photoelectric conversion elements 3 are provided only at one end if the characteristics of the incident light are known.

Further, the plate 1 may have a curved surface instead of a flat surface as in the embodiment, and can be selectively used depending on the purpose of use, such as a spherical surface or a cylindrical shape. Furthermore, since the incident intensity can be reduced by roughening the surface of the plate 1, it is possible to give a roughness distribution to the surface and make the characteristics shown in FIG. 2 more linear.

Furthermore, the object to be measured is not necessarily a light spot, and a light spot can also be obtained in the plate 1 by point-like incidence of radiation. In this case, it is preferable that scintillators are scattered within the plate 1. In addition, the materials mixed into the plate 1 include fluorescent agents,
In addition to the scintillator, a light diffusing material such as simple aluminum powder may be mixed, although the light intensity will be reduced.

Incidentally, the application of this incident position detection device such as a light spot is generally considered to be a measuring device.
In addition, it can also be used in digitizer input devices for computers and the like. Furthermore, even when inputting figures, it is possible to sufficiently recognize the input by moving the light spot in chronological order.

[Effects of the Invention] As explained above, the device for detecting the incident position of a light spot, etc. according to the present invention has an extremely simple configuration and can determine the position of a light spot or radiation, which is not possible with conventional devices due to the cost. A large-sized detection device can also be manufactured at low cost.

[Brief explanation of drawings]

The drawings show an embodiment of the incident position detection device such as a light spot according to the present invention, and FIG. 1 is a perspective view thereof, FIG. 2a is an output characteristic diagram of a plate, and FIG. c is an overall output characteristic diagram, and FIG. 3 is a perspective view of another embodiment. Code 1 is a plate, 1a to 1d are end faces, 2a to 2d
3 is a strip member, and 3a to 3d' are photoelectric conversion elements.

Claims (1)

[Scope of Claims] 1. A transparent or translucent strip that also contains a secondary luminous material or a scattering material, in close contact with the end face of a transparent or semitransparent plate containing a secondary luminous material or a scattering material. A member is arranged, a photoelectric conversion element is arranged at at least one end of the strip member, and a light spot or radiation is incident on the surface of the plate, thereby generating secondary light or scattered light inside the plate. is introduced into the strip member to generate two-dimensional or scattered light again, and the incident position of the light spot or radiation is detected from the light intensity obtained by the photoelectric conversion element. Position detection device. 2. An incident position detection device for a light spot or the like according to claim 1, wherein the secondary light emitter is a fluorescent agent. 3. The strip members are arranged on opposite end faces of the plate, and the incidence position in the direction perpendicular to the longitudinal direction of the strip members is determined from the ratio of output of the photoelectric conversion elements arranged on these strip members. An incident position detecting device for a light spot or the like according to claim 1, which detects the incident position of a light spot. 4. Arranging the photoelectric conversion elements at both ends of the strip member, projecting the incident position of the plate onto the strip member from the ratio of the outputs of both photoelectric conversion elements, and calculating the longitudinal direction of the strip member. An incident position detection device for a light spot or the like according to claim 1, which detects an incident position.