JPS6411059U

JPS6411059U -

Info

Publication number: JPS6411059U
Application number: JP10487187U
Authority: JP
Priority date: 1987-07-08
Filing date: 1987-07-08
Publication date: 1989-01-20

Description

[Brief explanation of the drawing]

第１図は本考案の第１実施例の構成を示す回路
図、第２図は白基準の読み取りの初期時のセンサ
出力、第３図は基準となるセンサ出力、第４図は
本考案の光量補正後のセンサ出力、第５図ａは本
考案の光量補正後のセンサ出力の次段の信号処理
のブロツク図、第５図ｂは本考案の光量補正後の
センサ出力の次段の信号処理のブロツク図、第６
図はセンサの光電変換特性、第７図はＬＥＤアレ
イの電流―照度特性、第８図はＬＥＤアレイの電
圧―照度特性、第９図は本考案の第２実施例の構
成を示す回路図、第１０図はセンサの光電変換特
性図、第１１図はＡ／Ｄコンバータの動作領域を
示す説明図、第１２図はその出力の説明図、第１
３図はＬＥＤの光量の経時変化特性図である。 Fig. 1 is a circuit diagram showing the configuration of the first embodiment of the present invention, Fig. 2 is the sensor output at the initial stage of reading the white reference, Fig. 3 is the reference sensor output, and Fig. 4 is the sensor output of the present invention. Figure 5a is a block diagram of the next stage signal processing of the sensor output after the light quantity correction of the present invention, and Figure 5b is the next stage signal of the sensor output after the light quantity correction of the present invention. Processing block diagram, No. 6
The figure shows the photoelectric conversion characteristics of the sensor, FIG. 7 shows the current-illuminance characteristics of the LED array, FIG. 8 shows the voltage-illuminance characteristics of the LED array, and FIG. 9 is a circuit diagram showing the configuration of the second embodiment of the present invention. Fig. 10 is a photoelectric conversion characteristic diagram of the sensor, Fig. 11 is an explanatory diagram showing the operating range of the A/D converter, Fig. 12 is an explanatory diagram of its output,
FIG. 3 is a characteristic diagram of the change in light amount of the LED over time.

Claims

[Claims for Utility Model Registration] 1. In a document reading optical device using an LED array light source and a contact type image sensor, the peak in the output of the image sensor when the white reference is read by the image sensor before reading the document. means for detecting a level; a reference voltage generating means for generating a reference voltage corresponding to a peak level of an image sensor output serving as a reference; detecting a ratio between the reference voltage and the peak level; An image signal reading correction device comprising a light amount control means for controlling the light amount of an LED array light source. 2. Image signal reading correction according to claim 1 of the utility model registration claim, characterized in that the light amount control means is configured to set the current applied to the LED array light source according to the ratio between the reference voltage and the peak level. Device. 3. The light amount control means includes a differential amplifier that generates a voltage difference between a reference voltage and a peak level, and an output of the differential amplifier that controls the current or voltage supplied to the LED array light source to adjust the output of the differential amplifier. An image signal reading correction device according to claim 1, characterized in that the image signal reading correction device is configured to include a energization control circuit section that operates so that the energization becomes zero.