JPS642925B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an optical signal divider used for dividing an optical signal into functional patterns in an analog tomography apparatus or the like.

(B) Prior Art When processing an optical signal, there are various cases in which it is necessary to divide the optical signal into functional patterns. Here, an analog tomography apparatus will be explained as an example. The applicant has already applied for an analog tomography device (Japanese Patent Application No. 53-37528 and
70534), convolution processing is performed on the optical signal obtained from the radiation detector while keeping it as an analog signal. First, a fan-shaped radiation beam that spreads within one plane is emitted, and the fan-shaped radiation beam that has passed through the object is detected by radiation detectors arranged in a row. Then, the profile (projection) becomes f(x), where x is the arrangement direction of the radiation detectors.
Data is obtained. In analog tomography equipment, this profile data is obtained as a light band 1 whose brightness changes in proportion to f(x) in the x direction, as shown in Figure 1, from a scintillator, which is a radiation detector. (The brightness is constant in the direction perpendicular to the x direction).

The convolution of profile f(x) and correction function g(x) is expressed as ∫ ^∞ _-∞ f(x')·g(x-x')dx'. Therefore, by relatively moving the mask 2 having light transmission windows 21 to 25 corresponding to the correction function g(x) shown in FIG. 1 in the x direction, the windows 21, 23, 25 corresponding to the positive portion and the window 22, 2 corresponding to the negative part.
After dividing the sum of the amounts of light passing through 4 and converting them into electrical signals, the convolution shown by the above equation can be performed by taking the difference.

(C) Purpose This invention is to separate an optical signal by dividing it at a dividing line of a light transmission window (in the above example, the line of g(x) = 0) corresponding to a function pattern provided on a mask as described above. The purpose of the present invention is to provide a splitter for optical signals that can lead to

(D) Configuration The optical signal splitter according to the present invention uses two prisms, and arranges them so that their respective optical signal input surfaces are adjacent to each other in one plane and their boundaries are straight lines. The boundary line on the optical signal input surface is made to coincide with the division line of the light transmission window forming the functional pattern in the mask, and the optical signal is led separately from the output surface of each of these two prisms.

(E) Embodiment In FIG. 2, an optical signal splitter 3 according to the present invention is composed of two prisms 4 and 5. These prisms 4 and 5 are parallelepiped-shaped prisms, and upper surfaces 41 and 51 are input surfaces for optical signals, and lower surfaces 4 and 5 are parallelepiped-shaped prisms.
6 and 56 are the output surfaces, and the other surfaces (side surfaces)
42 to 45 and 52 to 55 are provided with appropriate coatings to form reflective surfaces that reflect 100% of the light.
The input surfaces 41 and 51 are adjacent to each other in one plane, and the boundary line 3a thereof is a straight line. mask 2
is provided with a light transmission window 2b corresponding to the function pattern. The mask 2 is placed on the input surface 4 so that the dividing line 2a of this mask 2 coincides with the boundary line 3a.
1, Overlap on 51.

With this configuration, an optical signal incident from one of the windows divided by the dividing line 2a enters the input surface 41 of one prism 4, is reflected in the prism 4, and is guided to the output surface 46. Furthermore, the light entering from the other window divided by the dividing line 2a is transmitted to the input surface 51.
The light enters the prism 5, is reflected, and is guided to the output surface 56. In this case, the light output from the output surfaces 46 and 56 is the light that entered from the input surfaces 41 and 51 and was propagated in the prisms 4 and 5 by being reflected by the side wall surfaces, etc. This corresponds to the sum of the mixed and added lights.

With this optical signal divider 3, no matter how complex the function pattern is or what kind of dividing line there is, it is easy to use by simply aligning the dividing line 2a of the mask 2 with the boundary line 3a. The optical signal can be divided into two parts.

Therefore, the direction of the dividing line 2a of the mask 2 is set as the x direction, and the shape of the window 2b of the mask 2 is determined by the correction function g(x).
A light band 1 having a light intensity distribution f(x) in the x direction is imaged on the surface of this mask 2, and then the prisms 4 and 5 to which the mask 2 is attached are integrated into this It is moved in the x direction relative to the light band 1. And the output surface 4 of the prisms 4 and 5
Each of 6 and 56 is provided with a suitable photodetector that generates an electrical signal corresponding to the total output light of each surface thereof, and the electrical signal from the photodetector is provided at each position of the above-mentioned x-direction movement. If the difference is taken, it means that a convolution of f(x) and g(x) has been performed.

Note that the shape of the prism is not limited to the parallelepiped shape shown in FIG. 2, but also the lower surfaces 76, 86 as shown in FIG.
The optical signal splitter 6 can also be formed using rectangular parallelepiped prisms 7 and 8 whose only surfaces are inclined. In this case, part 7 of the side surfaces 73, 83
3b and 83b are transparent, and the other parts 73a and 83b are transparent.
83a as a reflective surface, and the side surfaces 72, 74, 75, 8 except for the upper surface 71, 81 which is the input surface.
2, 84, 85 and lower surfaces 76, 86 are reflective surfaces. The shapes of the output surfaces 73b and 83b can be adapted to the input surface of a photoelectric device or the like that is brought into close contact with the output surfaces.

(f) Effects The optical signal splitter according to the present invention has a simple structure, is easy to manufacture, and can correspond to any function pattern.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view for explaining division of optical signals in an analog tomography apparatus, FIG. 2 is a schematic perspective view showing one embodiment of the present invention, and FIG. 3 is another embodiment. FIG. 1... Light band, 2... Mask, 2a... Parting line, 2b, 21-25... Light transmission window, 3, 6...
Divider, 4, 5, 7, 8... Prism, 41, 5
1, 71, 81...Input surface, 46, 56, 73
b, 83b...Output surface.

Claims (1)

[Claims] 1. Two prisms are arranged so that their optical signal input surfaces are adjacent to each other in one plane and their boundaries are straight lines, and the boundaries on the optical signal input surfaces are formed into light transmission windows forming a function pattern in a mask. An optical signal splitter configured to match the dividing line of the prism and to guide optical signals separately from the output faces of each of the two prisms.