JPS6112170A - Picture writer - Google Patents

Abstract

PURPOSE:To correct ununiformity different in luminous amount attenuation rates by obtaining a correction amount of ununiformity by a measuring value of the luminous amount attenuation rate, and inserting a luminous amount correcting plate between a luminous amount variable light source and a photosensitive recording medium. CONSTITUTION:A digital picture signal maximizing the output luminous amount of a luminous amount modulator 2 is transmitted from an input terminal 11. A photo deflector 4 is shaken, the light is received by a luminous amount detector 6 to measure the luminous amount at each scanning point. The analog luminous amount signal is converted (7) into a digital luminous amount signal and inputted to an operating circuit 8, and the digital luminous amount correction signal is outputted to a buffer memory 9. The digital picture signal from the input terminal 11 and the digital luminous amount correction signal from the buffer memory 9 are converted (10) into the analog signal, added (13) and outputted to a luminous amount modulator driver 13. The luminous amount corresponding to a digital picture signal is received by the luminous amount detector 6, and recorded by synchronizing the digital picture signal and the deflection of the optical polarizer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a light beam scanning image writing device that uses a scanning optical system that scans a light beam, and more particularly.

The present invention relates to a technique that is effective when applied to image writing devices that widely require light intensity gradation.

[Background technology]

Generally, when image information such as medical images is stored in a storage device, a light beam scanning image writing device is used as a technical means for copying this image information onto a photosensitive recording medium or the like.

The light beam scanning technology means in such a light beam scanning image writing device is based on various conditions regarding the optical transmission path from the light source to the light receiving unit such as a photosensitive recording medium or a light amount detector, such as the optical path of the light beam. It was non-uniform depending on the scanning position of the light receiving section.

Conventionally, devices using this optical system have narrow light intensity gradations and narrow scanning ranges, making it possible to ignore non-uniformity.

However, in order to widen the gradation of the light intensity of the scanning light beam and to widen the scanning range in order to miniaturize the device, there is a problem that non-uniformity depending on the scanning position cannot be ignored.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a technical means capable of correcting non-uniformity of the light quantity attenuation rate, which varies depending on the light beam scanning position, in a light beam scanning type image writing device.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, in a light beam scanning image writing device, the light intensity attenuation rate that changes depending on the light beam scanning position is measured, the amount of correction for non-uniformity is determined from this measured value, and this correction amount is synchronized with the light beam scanning. A non-uniformity correction technique that changes the light intensity of a variable light source by changing the light intensity, or a non-uniformity correction plate that corresponds to the amount of non-uniformity correction measured and prepared in advance is inserted between the variable light source and the photosensitive recording medium. This method uses corrective technical means.

[Structure of the invention]

Hereinafter, the configuration of the present invention will be explained along with examples. In all the explanations of the embodiments, parts having the same functions are denoted by the same reference numerals, and repeated explanations thereof will be omitted.

1 and 2 are diagrams for explaining an image writing device according to an embodiment of the present invention, with FIG. 1 being a block diagram showing the overall schematic configuration thereof, and FIG.

FIG. 2 is a block diagram showing a specific configuration of the arithmetic circuit shown in FIG. 1. FIG.

In FIG. 1, l is a light source, 2 is a light amount modulator that modulates the amount of light, 3 is a light amount modulator driving device that generates a modulation signal for the light amount modulator 2, and 4 is a vibrating mirror.

A light deflector such as a rotating mirror, and 5 an fθ lens that focuses the light beam at a position proportional to the deflection angle of the light deflector 4.

A light condenser such as an fθ mirror, 6 a light intensity detector that measures the light intensity at each scanning point, and 7 an analog-to-digital converter (hereinafter simply referred to as , A/D converter), 8 is an arithmetic circuit that generates a digital light amount correction signal for correcting the digital light amount signal, 9 is a buffer memory that stores the output digital light amount correction signal of the arithmetic circuit 8, and 10 is a digital light amount A digital-to-analog converter (hereinafter simply referred to as a D/A converter) that converts a correction signal into an analog light amount correction signal, 11
is the terminal into which the digital image signals that make up the image are input,
12 is a D/A converter that converts a digital image signal into an analog image signal, and 13 is an addition circuit that adds the analog image signal and the analog light amount correction signal.

In FIG. 2, 14 is a terminal into which the digital light amount signal at each scanning position from the A/D converter 7 is input, 15 is an inverter that inverts the input digital light amount signal at each scanning position, and 16 is an inverter. 17 is a minimum value detector that detects and outputs the minimum value among the digital light amount signals at each scanning position that have been inverted by the inverter 15; Minimum value detector 17
19 is a subtracter that calculates the difference between the digital light amount signal at each scanning position stored in buffer memory 16 and the minimum value stored in buffer memory 18; An interpolator 21 interpolates data in accordance with the scanning position of a digital image signal inputted to an input terminal 11, and an output terminal 21 outputs a digital light amount correction signal after arithmetic processing.

Next, the operation of this embodiment will be explained.

In FIGS. 1 and 2, since nothing is input to the buffer memory 9 at first, a digital light amount correction signal is input to the buffer memory 9.

A digital image signal that maximizes the output light amount of the light amount modulator 2 is sent from the input terminal 11. The light deflector 4 is swung, the light quantity detector 6 receives the light, and the light quantity at each scanning point is measured. At this time, a plurality of light receiving elements may be measured, or - number of light receiving elements may be placed in order at each scanning point, and the optical deflector 4 may be swung. The analog light amount signal obtained here is converted into a digital light amount signal by the A/D converter 7 and input to the arithmetic circuit 8. In the arithmetic circuit 8, as shown in FIG.
to invert it and convert it to negative logic. The converted digital light amount signal at each scanning position is stored in a buffer memory 16,
First, the signal is output to the minimum value detector 17, and the minimum value at each scanning position is determined and stored in the buffer memory 18. A subtracter 19 calculates the difference between this minimum value and the value of the converted digital light amount signal at each scanning position stored in the buffer memory 16.
Find it by Furthermore, data is interpolated using the interpolator 20 so as to match the scanning position of the digital image No. 4g inputted to the input terminal 11. If the scanning position of the digital image signal and the scanning position of the measured digital light amount signal match, the interpolator 20 can be omitted. The digital light amount correction signal that has undergone the arithmetic processing is output from the output terminal 21 to the buffer memory 9.

The digital image signal from the input terminal 11 and the digital light amount correction signal from the buffer memory 9 are converted into an analog image signal and an analog light amount correction signal by D/A converters 12 and 10, respectively, and the two signals are converted by the adder circuit 13. The sum is added and output to the light amount modulator driving device 3. The two digital signals may be added in their digital form and converted into an analog signal after the addition.

By synchronizing the digital image signal and the deflection of the optical deflector 4, the light amount detector 6 can receive the amount of light corresponding to the digital image signal. When a photosensitive recording medium is placed at the position of the light amount detector 6, an image corresponding to a digital image signal can be written on the photosensitive recording medium.

3 and 4 are diagrams for explaining an image writing device according to another embodiment of the present invention, in which FIG. 3 is a block diagram showing the overall schematic configuration, and FIG. FIG. 3 is a block diagram showing a specific configuration of an arithmetic circuit for manufacturing the light amount correction plate shown in FIG.

The image writing device of this embodiment uses a light amount correction plate 22 in place of the light amount attenuation rate detector and the light amount correction circuit of the image writing device of the example shown in FIG. It is a medium.

That is, the image writing apparatus of this embodiment inputs a light beam from a light source 1 to a light amount modulator 2, as shown in FIG. On the other hand, the digital image signal input to the input terminal 11 is converted into an analog image signal by the D/A converter 12 and input to the light amount modulator driving device 3. The light beam is modulated by the output signal of the light quantity modulator driving device 3 and is incident on the light deflector 4. Digital image signal and the optical deflector 4
The deflection of the light is synchronized and the light is made to enter the light amount correction plate 22.

This light amount correction plate 22 writes onto the photosensitive recording medium 23 an image corresponding to the input digital image signal with a uniform attenuation rate of the light amount at any scanning position.

The light amount correction plate 22 uses an arithmetic circuit shown in FIG. 4 to measure in advance the light amount attenuation rate that changes depending on the light beam scanning position, calculates a light amount correction value from this measured value, and calculates the light amount correction value based on this light amount correction value. Create.

Next, the arithmetic circuit shown in FIG. 4 will be explained.

This arithmetic circuit has almost the same circuit configuration as the arithmetic circuit shown in FIG. The value detector 17 determines the minimum value at each scanning position and stores it in the buffer memory 18. A subtracter 19 calculates the difference between this minimum value and the digital image signal at each scanning position stored in the buffer memory 16.

Furthermore, data is interpolated using an interpolator 20 to match the scanning position of the digital light amount signal. If the scanning position and the scanning position of the measured digital light amount signal match, the interpolator 20 can be omitted.

The digital light amount correction plate signal for which the calculation processing has been completed is output from the output terminal 21. Light amount correction plate 2 corresponding to this signal
2 is made and inserted between the light condenser 5 and the photosensitive recording medium 23.

The light amount correction plate 22 can be manufactured not only from an arithmetic circuit, but also by inserting a Yin-Yang reversal film at the position of the light amount correction plate 22 and exposing it by shaking the light deflector 4, and using this as the light amount correction plate. You can also do that.

〔effect〕

As explained above, according to the novel technical means disclosed in this application, the following effects can be obtained.

(1) In a light beam scanning image writing device, measure the light intensity attenuation rate that changes depending on the light beam scanning position, use this measurement value to determine the amount of correction for non-uniformity, and synchronize this correction amount with the light beam scanning. The amount of light from the light source can be changed by adjusting the amount of light emitted from the light source, or by inserting a light amount correction plate between the light source and the photosensitive recording medium that corresponds to the amount of non-uniformity correction measured and prepared in advance. It is possible to correct the non-uniformity of different light quantity attenuation rates.

(2) By eliminating the non-uniformity of the light attenuation rate due to the scanning position that occurs in the optical system that scans the light beam, it is possible to record the image corresponding to the image signal on the image recording medium. The matched image can be written to a photosensitive recording medium.

The present invention has been specifically explained above using examples, but
It goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit thereof.

[Brief explanation of drawings]

1 and 2 are diagrams for explaining an image writing device according to an embodiment of the present invention. FIG. 1 is a block diagram showing the overall schematic configuration, and FIG. 3 and 4 are diagrams for explaining an image writing device according to another embodiment of the present invention, and FIG. FIG. 4 is a block diagram showing the overall schematic configuration of the light amount correction plate, and FIG. 4 is a block diagram showing an arithmetic circuit for manufacturing the light amount correction plate shown in FIG. In the figure, l: light source, 2: light amount modulator, 3: light amount modulator drive device, 4: light deflector, 5: light collector, 6: light amount detector , 7... A/D converter, 8...
・Arithmetic circuit. 9.16.18...Buffer memory, 10,12...
・D/A converter, 11.14...input terminal, 13...
- Addition circuit, 15... Inverter, 17... Minimum value detector, 20... Interpolator, 21... Output terminal, 22...
'・Light amount correction plate, 23... Photosensitive recording medium.

Claims (2)

[Claims] (1) In a light beam scanning type image writing device consisting of a light intensity variable light source, a light deflector, a photosensitive recording medium, etc., a light intensity attenuation rate detector that measures a light intensity attenuation rate that changes depending on the light beam scanning position, and the light intensity An image writing device comprising a light amount correction circuit that corrects the light amount of a light beam according to the output of an attenuation rate detector. (2) In a light beam scanning image writing device consisting of a variable light source, a light deflector, a photosensitive recording medium, etc., light intensity correction is made based on a light intensity attenuation rate that changes according to a pre-measured light beam scanning position. An image writing device characterized by comprising a nonuniformity correcting means for inserting a plate between a variable light amount light source and a photosensitive recording medium.