JPS62276956A - Picture information reader - Google Patents

Abstract

PURPOSE:To send accurate picture information without invasion of noise by adhering an optical guide and a photodetecting means at one point by means of a conductive adhesives. CONSTITUTION:An adhesives 58 is applied as a point to the midpoint of an emission face 56 of an optical guide 54 of a picture information reader 30 and the optical guide 54 and a long filter 52 are adhered by the adhesives 58. Thus, even if the optical guide 54 and the long filter 52 are expanded by the heating of a photo-multiplier 32, the possibility of the suppression of thermal expansion of the optical guide is precluded and the possibility of generation of cracks to the optical guide 54 is precluded.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention The present invention relates to an image information reading device, and more specifically, for example, in a radiation image information recording and reproducing system using a stimulable phosphor sheet. The present invention relates to an image information reading device that detects radiation image information obtained from a fluorescent phosphor sheet using a photomultiplier configured in an elongated shape via a light guide.

When certain types of phosphors are irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet light, etc.), a portion of this radiation energy is stored in the phosphor, and then this When the phosphor is irradiated with excitation light such as visible light, the phosphor generates stimulated luminescent light in response to the accumulated energy. A phosphor exhibiting such properties is called a stimulable phosphor.

Using this stimulable phosphor, radiation image information of a subject such as a human body is stored and recorded on a sheet made of stimulable phosphor, which is then scanned with excitation light such as a laser beam to produce stimulated luminescence. The applicant has developed a number of radiographic image information recording and reproducing devices that photoelectrically read this stimulated luminescent light to obtain an image signal, and further process the image signal to obtain a radiographic image of a subject with excellent diagnostic suitability. It has been proposed (for example, Japanese Patent Application Laid-Open No. 5
No. 5-12429, No. 56-11395, No. 55-1
No. 63472, No. 56-104645, No. 55-11
6340 etc.).

Therefore, image 1'fff! reads radiation image information from the stimulable phosphor sheet. An example of a lii reading device is shown in FIG. That is, this image information reading device includes a transport mechanism 4 that transports the stimulable phosphor sheet 2, an optical system 8 that irradiates the stimulable phosphor sheet 2 with a laser beam 6, and a stimulable phosphor sheet 1-2. It basically consists of a reading mechanism 10 that photoelectrically reads the image emotions K stored and recorded in the .

The conveyance mechanism 4 has an endless heald 14 stretched between a pair of rollers 12a and 12b, and this endless belt 14 conveys the stimulable phosphor sheet 2 in the sub-scanning direction (direction of arrow B). Further, the optical system 8 includes a laser oscillation tube 16 that outputs the laser beam 6, and a galvanometer mirror 20 that scans the laser beam 6 in the main scanning direction (arrow A direction) of the stimulable phosphor sheet 2. On the other hand, the reading mechanism 10 includes a light guide 22 that collects the stimulated luminescent light emitted from the stimulable phosphor sheet 2 by the laser beam 6, and a photomultiplier 24 that photoelectrically converts the stimulated luminescent light. It is comprised of a signal processing section 26 that performs predetermined processing on the electrical signal and displays it on a CRT or the like.

Next, the operation of the image information reading device configured as described above will be explained.

Laser light 6 outputted from laser oscillation tube 16 is irradiated onto stimulable phosphor sheet 2 via galvanometer mirror 20 . In this case, the laser beam 6 is deflected in one dimension by the galvanometer mirror 20 and scans the stimulable phosphor sheet 2 in the main scanning direction (in the direction indicated by the arrow). On the other hand, the stimulable phosphor sheet 2 is conveyed in the sub-scanning direction (direction of arrow B) by an endless belt 14 stretched between rollers 12a1 and 12b. As a result, the laser beam 6 scans the entire area of the stimulable phosphor sheet 2 two-dimensionally.

The stimulable phosphor sheet 2 irradiated with the laser beam 6 generates stimulated luminescent light in accordance with the image information stored and recorded thereon. This stimulated luminescent light is incident on one end surface of a transparent light guide 22 disposed near the stimulable phosphor sheet 2 . Here, in the light guide 22, one end surface located near the stimulable phosphor sheet 2 is formed in a straight line parallel to the main scanning direction (direction of arrow A), and gradually increases toward the other end. It is formed into a cylindrical shape, and the other end surface is connected to the light receiving surface of the photomultiplier 24. Therefore, the stimulated luminescent light entering from one end surface of the light guide 22 enters the photomultiplier 24 via this light guide 22. The stimulated luminescent light incident on the photomultiplier 24 is converted into image information as an electrical signal, and this image information is subjected to predetermined processing by the signal processing section 26 and then displayed on a display means such as a CRT. Alternatively, it will be recorded on a recording medium such as a magnetic tape.

Incidentally, in such an apparatus, a photomultiplier 24 having a circular light-receiving surface and a light guide 22 are used as the reading mechanism 10 for detecting stimulated luminescence light. In this case, the light guide 22 has a linear entrance surface close to the stimulable phosphor sheet 2, and a cylindrical exit surface coupled to the photomultiplier 24. , the processing becomes difficult and the processing cost is high.
It has been pointed out that the disadvantage is that it increases the manufacturing cost of the device. Furthermore, since the light guide 22 is largely deformed from its entrance surface to its exit surface, there is a problem in that a portion of the stimulated luminescence light guided inside the light guide 22 leaks to the outside, reducing light transmission efficiency. Therefore, such a reading mechanism 1
0, the stimulable phosphor sheet 2 and the photomultiplier 2
By setting a sufficiently large distance between the light guide 22 and the light guide 22, it is necessary to minimize the amount of deformation of the light guide 22 and ensure light transmission efficiency, which results in the inconvenience of increasing the size of the structure.

Therefore, in view of the above-mentioned problems, the applicant of the present application aims to detect light emitted from a stimulable phosphor sheet without using a large and complicatedly shaped light guide, thereby reducing the size and manufacturing cost. We have developed an image information reading device that can significantly improve light transmission efficiency and have already applied for a patent (Japanese Patent Application No. 156255/1982). The present invention relates to an elongated photomultiplier having a light-receiving surface extending along the main scanning direction and disposed close to a stimulable phosphor sheet in an image information reading device as described above. It was made by In this case, the light guide that guides the stimulated luminescence light emitted from the stimulable phosphor sheet by laser light irradiation to the photomultiplier has an entrance surface formed linearly along the main scanning direction of the sheet; The light guide 22 may have a substantially rectangular shape having a linear exit surface formed along the light receiving surface of the photomultiplier, and does not need to be transformed into a complicated shape like the light guide 22 described above. Therefore, the reduction in light transmission efficiency due to this light guide can be minimized, and the photomultiplier can be placed close to the sheet, which has the advantage of making the reading mechanism more compact. is obtained.

By the way, in order to ensure the light transmission efficiency and facilitate the processing work, such a light guide usually uses a light guide sheet-like member made of acrylic resin or the like. On the other hand, the elongated photomultiplier has a light receiving surface made of a member such as glass. The exit surface of the light guide and the light receiving surface of the photomultiplier must be coupled extremely tightly.

In this case, the light guide and photomultiplier are usually bonded together using a transparent adhesive or the like.

However, the acrylic resin constituting the light guide and the glass constituting the light receiving surface of the photomultiplier have significantly different coefficients of thermal expansion, and on the other hand, the photomultiplier undergoes considerable high heat when amplifying photoelectrons. emits.

Therefore, the length of expansion of the photomultiplier and the light guide differs as the temperature changes, and as a result, there is a possibility that cracks such as cracks may occur in the light guide. Moreover, not only the light transmission efficiency is significantly reduced, but also the problem arises that image information due to stimulated luminescence light is not transmitted accurately.

The present invention has been made in order to overcome the above-mentioned disadvantages, by joining the light detection means and the light guide that guides the light to the light detection means at one point using a light-guiding adhesive. Image information reading that can prevent cracks in the light guide due to heat generated by the light detection means, and therefore does not reduce the light transmission efficiency of the light guide and enables accurate transmission of image information. The purpose is to provide equipment.

In order to achieve the above object, the present invention provides main scanning means for main-scanning a sheet on which image information is recorded with a light beam and generating light containing the image information from the sheet;
Image information reading comprising a sub-scanning means for sub-scanning by moving the 1M destination light beam relative to the sheet in a direction substantially perpendicular to the main-scanning direction, and a light-detecting means for detecting light obtained from the sheet. In the apparatus, the light detection means includes a long photomultiplier having a light receiving surface extending along the main scanning line, and a light guide that guides light obtained from the sheet to the light detection means is used for the light detection. Preferred embodiments of the image information reading device according to the present invention will be described below with reference to the accompanying drawings, in particular, which is characterized in that it is configured to be bonded to the means at one point with a light-guiding adhesive. Explain in detail.

In FIG. 2, reference numeral 30 indicates an image information reading device according to the present invention. In this case, the same reference numerals are given to the same components as in the image information reading device shown in FIG. 1, and detailed explanation thereof will be omitted.

Therefore, the photomultiplier 32 constituting the image information reading device 30 employs an electrode structure generally referred to as a Venetian blind type. That is, Figure 3a
As shown in FIGS. and b, the main body 34 of the photomultiplier 32 is made of glass or the like, and has a cylindrical shape with a vacuum inside. A photocathode (optical power source) 38 is provided in the main body 34 facing a long light-receiving surface 36, and below the photocathode 38 there are a plurality of electrodes (dynodes) 40a to 40a having a secondary electron emission effect. A multiplier section 42 in which 40 m is combined is provided. Each of the dynodes 40a to 40m is formed into a blind shape by making a number of U-shaped cuts in one conductive plate and bending the plate. A shield electrode 44 is provided opposite to the dynode 40m at the lowest end of the multiplier 42, and an anode 46 inside the shield electrode 44 collects the electron flow multiplied by the multiplier 42 and takes it out as a signal. is installed. Each of these electrodes is electrically connected to a number of terminal groups 48 corresponding to the number of electrodes provided at one end of the main body 34. In this case, the dynodes 40a to 40m
The shield electrode 44 is fixedly held within the main body 34 via a support member 50 made of an insulator.

The long photomultiplier 32 used in this embodiment may be a conventionally known photomultiplier equipped with a multiplier section made of other types of electrodes or a multiplier section formed by combining a plurality of types of electrodes. It can also be formed by elongation.

Therefore, as shown in FIG. 4, on the light-receiving surface 36 of the photomultiplier 32 configured as described above, a long filter 52 that transmits only the stimulated luminescence light from the stimulable phosphor sheet 2 is installed. Joined.

In this case, the long filter 52 is the photomultiplier 3
It is made of the same glass member as the main body 34 that constitutes the light receiving surface 36 of No. 2, and both ends thereof are fixed to the photomultiplier 32 by, for example, healds (not shown).

On the other hand, a long light guide 54 made of a lightweight material such as acrylic resin is bonded to the long filter 52 . in this case,
At the center of the exit surface 56 of the light guide 54 from which the stimulated luminescent light from the stimulable phosphor sheet 2 exits, for example, an epoxy adhesive 58 is applied in dots as shown in FIG. is,
The light guide 54 is bonded to the elongated filter 52 via this adhesive 58. Note that a gap is defined between the light guide 54 and the long filter 52 by the thickness of the adhesive 58, and this gap is filled with a light-guiding liquid filler 60 having a high surface tension such as silicone oil. be done.

The image information reading device according to the present invention is basically constructed as described above.Next, its operation and effects will be explained.

Note that the operation of the image information reading device 30 according to the present invention is as follows.
This is substantially the same as the conventional image information reading device shown in the figure, and therefore its operation will be briefly described.

Therefore, the stimulable phosphor sheet 2 on which image information of the subject is recorded by X-rays or the like is conveyed in the sub-scanning direction (direction of arrow B) by an endless belt 14 constituting the conveyance system 4. On the other hand, the surface of the stimulable phosphor sheet 2 is irradiated with laser light 6 emitted from the laser oscillation tube 16 in the main scanning direction (arrow A direction), and the stimulable phosphor sheet 2
The image information of the subject stored and recorded is extracted as stimulated luminescence light. This stimulated luminescent light is produced by the stimulable phosphor sheet 2.
The light enters from the incident surface of the light guide 54 disposed along the main scanning direction, and enters the photocathode 38 from the light receiving surface 36 of the photomultiplier 32 via the elongated filter 52.

The photomultiplier 32 converts this stimulated luminescence light into an electrical signal and sends it to the signal processing section 26. Then, the signal processing unit 26 performs predetermined processing on the electrical signal, and then outputs the image information as a visible image on a CRT or the like or records it on a recording medium such as a magnetic tape.

Here, the photomultiplier 32 generates considerable heat when converting the stimulated luminescent light into an electrical signal. This heat heats the light receiving surface 36 of the photomultiplier 32, and also causes the long filter 52 bonded to the light receiving surface 36 to heat up.
and heating the light guide 54. As a result, the main body 34, the elongated filter 52, and the light guide 54 that constitute the light receiving surface 36 are each expanded mainly in the longitudinal direction by the heat.

In this case, the main body 34 constituting the light receiving surface 36 of the photomultiplier 32 and the elongated filter 52 are made of the same solid material. Therefore, their thermal expansion coefficients are the same, and there is no possibility that thermal strain will occur between the main body 34 and the elongated filter 52. However, the light guide 54 joined to the long filter 52 is usually made of a material such as acrylic resin in order to make it easy to process and lightweight. Therefore, since the elongated filter 52 and the light guide 54 have significantly different coefficients of thermal expansion, thermal distortion occurs when these members are integrally joined and heated, and the light guide 54
There is a risk that cracks may occur.

By the way, in the image information reading device 30 according to the present invention, an adhesive 58 is applied in dots to the center of the exit surface 56 of the light guide 54, and the light guide 54 is coated via the adhesive 58.
and the elongated filter 52 are joined together. Therefore,
The light guide 54 is heated by the photomultiplier 32.
Even when the long filter 52 is expanded, the thermal expansion of the light guide 54 is not suppressed. Therefore, thermal distortion does not occur due to the difference in the coefficients of thermal expansion, and there is no possibility that cracks such as cracks will occur in the light guide 54.

Note that a gap is defined between the long filter 52 and the light guide 54 by the thickness of the adhesive 58, and this gap is filled with a filler 60 such as silicone oil. Therefore, there is no possibility of problems such as uneven light transmission occurring due to differences in light transmittance between the adhesive bonded portion and the non-bonded portion. Here, it is also possible to configure the adhesive 58 to be applied to one end side of the exit surface 56 of the light guide 54.

As described above, according to the present invention, optical information obtained from a sheet-shaped recording medium is guided to a photodetecting means via a light guide, and the photodetecting means photoelectrically converts the optical information to obtain image information. In the information reading device, the light guide and the light detection means are configured to be joined at one point using a light-guiding adhesive. Therefore, when the light detecting means generates heat, there is no possibility that cracks or the like will occur in the light guide due to the difference in coefficient of thermal expansion between the light detecting means and the light guide. Therefore, it is possible to obtain an image information reading device in which the optical information collected by the light guide is extremely efficiently sent to the photodetecting means, and it is possible to transmit accurate image information without mixing noise. .

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
For example, it may be an image reading device that detects reflected light or transmitted light from a document sheet other than a radiation image information reading device. Of course, various improvements and changes in design are possible without departing from the gist of the present invention, such as by simply joining the guides.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an image information reading device according to the prior art, FIG. 2 is a configuration diagram showing an embodiment of an image information reading device according to the present invention, and FIG. 3a is a configuration diagram of an image information reading device according to the present invention. FIG. 3 is a sectional view taken along line bb of FIG. 3a; FIG. 4 is a side view of essential parts in an embodiment of the image information reading device according to the present invention; The figure is an exploded perspective view of essential parts of an embodiment of an image information reading device according to the present invention. 2...Storage phosphor sheet 4...Transportation mechanism 6.
...Laser light 8...Optical system 10...
Reading mechanism 30... Image information reading device 32... Photo multiplier 36... Light receiving surface 5
2... Long filter 54... Light guide 5
6... Injection surface 58... Adhesive 60
... Filler FIo, 1 FIG, 4

Claims (3)

[Claims] (1) Main scanning means for main-scanning a sheet on which image information is recorded with a light beam to generate light containing the image information from the sheet, and relatively moving the sheet and the light beam in the main scanning direction. In an image information reading device comprising a sub-scanning means that performs sub-scanning by moving in a substantially vertical direction, and a light detection means that detects light obtained from the sheet, the light detection means extends along a main scanning line. It consists of a long photomultiplier having a light-receiving surface, and is configured such that a light guide that guides the light obtained from the sheet to the light detection means is bonded to the light detection means at one point with a light-guiding adhesive. An image information reading device characterized by: (2) In the apparatus according to claim 1, the sheet is a stimulable phosphor sheet on which radiation image information is accumulated and recorded, and the light beam is accumulated and recorded on the stimulable phosphor sheet. The light detecting means includes a filter on the light receiving surface of the photomultiplier, and the light guide is attached to the filter at one point with adhesive. Image information reading device made by joining. (3) In the apparatus according to claim 1 or 2, a gap other than the joint between the light guide and the light detection means is filled with a light-guiding liquid filler. Information reading device.