JPS6073323A - Photodetector - Google Patents

Abstract

PURPOSE:To improve measuring efficiency of intensity of a light by condensing beams from a specimen with a cylindrical condenser provided with a reflecting mirror on its inside surface and leading the light to a detector. CONSTITUTION:Light emitted from a laser beam source 2 is reflected with a rotating mirror 3 and flashed onto a specimen 1 moving in the direction of A after passing through incident slit 6 and read-out slit 7 of a condenser 4. The reflected beam is flashed onto the condenser 4 through the read-out slit and reflected with the reflecting mirror 8 provided on its inside surface and then condensed and flashed into detectors 5, 5. The output is added by an adder 11 after passing through amplifier 9, A/D convertor 10. Thus, measuring efficiency of intensity of the light is improved.

Description

Detailed Description of the Invention [Technique of the Invention 1 (Field 1)] The present invention is directed to an object such as a printing paper, a measuring phosphor, etc.
The present invention relates to a photodetection device that irradiates u L/- laser light and measures the intensity of the light emitted therefrom.

[Techniques of the invention (4: Background and problems thereof]) Conventional photodetecting devices have a laser beam irradiated on the surface of the object by placing, for example, a glass fiber r bar near the irradiation point of the beam. - A light guiding object of tγ was installed, and the light from the object was introduced from one end of the filled object, and the intensity of the light was measured by a detector at the other end.

However, in the conventional device described above, only a small portion of the light emitted from the object by laser beam irradiation is guided to the light guide and contributes to the measurement of the light intensity by the detector.
The measurement efficiency is extremely poor.

Therefore, unless the output of the incident laser beam is made sufficiently large, a signal with a practically acceptable S/N ratio cannot be obtained, and the scanning speed of the incident laser beam cannot be increased. .

[Objective of the Invention 1] The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to provide a photodetection device that can contribute to a significant improvement in the efficiency of measuring light intensity.

[Summary of the Invention] The outline of the present invention for achieving the above object is as follows.
11 A cylindrical condensing body surrounded by a mirror is provided with an incident slit for the laser beam and a reading slit that receives light from an object to be read irradiated with the incident laser beam, facing each other. The present invention is characterized in that a detector is provided at at least one end of the body to which light from the object is guided by the reflecting mirror.

[Embodiment of the Invention] An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In the figure, reference numeral 1 indicates an object such as printing paper or stimulable phosphor that can be read out by light. It is sent in the scanning direction A.

Above the object 1 is a laser beam for scanning the object 1 at high speed in the main scanning direction B (perpendicular to the sub-scanning direction A). l! 2 and a rotating mirror 3. The rotating mirror 3 for main scanning may be replaced with a polygonal rotating mirror.

Between the object 1 and the rotating mirror 3, a cylindrical condenser 4 is installed along the main scanning direction B close to the object 1, and a photomultiplier is installed at both ends of the condenser 4. Detectors 5, 5 for detecting light such as the like are also provided. The light condenser 4 has an upper and a lower part thereof facing each other, and has an entrance for receiving a laser beam scanned in the main scanning direction B and guiding the light R emitted from the object 1 into the light condenser 4 for reading. A slit 6 and a reading slit 7 are provided on the inner surface of the condenser 4, and the light R introduced from the reading slit 7 is transmitted to the detectors 5 at both ends.
A reflecting mirror 8 is provided around the periphery to guide the light while reflecting the light. The entrance slit 6 and the reading slit 7 have groove widths and lengths necessary to allow the incidence of the laser beam optically scanned in the main scanning direction B and the introduction of the light R without waste.

A reflecting mirror 8 disposed around the inner surface of the condenser has a reading ring.
It is formed with a curved surface that guides the light entering from the door to the detectors 5, 5 at both ends without waste.

In the figure, 9 is an amplifier, 10 is an A/D converter, and 11 is an adder.

Next, the operation of the above-mentioned components will be described.

A linear laser beam emitted from a laser light source 2 passes through a rotating mirror 3, an entrance slit 6 and a reading slit 7 of a condenser 4, and is irradiated onto an object 1. The light R emitted from the object 1 by this irradiation enters the cylindrical condensing body 4 through the reading slit 7, and is guided to the detectors 5.5 at both ends while being reflected by the reflecting mirror 8 on the inner surface. The light R guided in this way is outputted from each detector 5.5 as an electric signal according to the light intensity, and the output is amplified by each amplifier 9. For example, every 10 μs, each A/D The analog output is converted into a digital signal by a converter 10, and the signals are added by an adder 11 to perform measurement.

In this way, the laser beam is scanned in the main scanning direction B by the mirror 3 rotated by the drive device (not shown), and the object 1 is moved in the sub-scanning direction by the drive belt (not shown). By sequentially changing the irradiation point on the object 11, the image recorded on the object 1 will be read out as an electrical signal and measured sequentially.

This image signal is then sent to a reproducing device such as a laser recording device or a CRT display, and the image recorded on the object is reproduced and used for recording, 11J2 inspection, etc.

Although one embodiment of the present invention has been described above in detail, it goes without saying that the present invention is not limited to the above-mentioned embodiment and can be implemented with appropriate modifications within the scope of the gist of the present invention. Nor. For example, in the above embodiment, the detectors were provided at both ends of the cylindrical light collector, but the detector may be provided only at one end of the cylindrical light collector, and the light is focused on the detector provided at this one end. It guides the light that enters the body while reflecting it. Alternatively, the analog outputs from the detectors may be directly added as analogs. Furthermore, the present invention is also applicable to measuring the intensity of transmitted light.

[Effects of the Invention] As explained above, the present invention is configured so that light from an object can be guided to a detector without waste by using a cylindrical condenser with an anti-mirror arranged around the inner surface. As a result, the light intensity measurement efficiency is significantly improved, so even if the output of the scanning speed of the incident laser beam is decreased and the scanning speed of the incident laser beam is increased, the S/N ratio can be maintained sufficiently for practical use. This has the effect of making it possible to obtain a signal that is accurate.

[Brief explanation of the drawing]

1 and 2 are schematic illustrations showing an embodiment of the apparatus according to the invention. 1...Object, 2...Light source, 4...
...Concentrator, 5...Detector, 6...
Incidence slit, 7...Reading slit, 8...
...Reflector, R...Light.

Claims (1)

[Claims] A cylindrical condenser with a reflecting mirror surrounding the inner surface is provided with a laser light input ring 1 and a reading ring which receives light from an object to be read irradiated with the incident laser light, facing each other. 1. A photodetecting device, further comprising a detector provided at at least one end of the light condenser to which light from the counterweight is guided by the reflecting mirror.