JPS60261247A - Shading device - Google Patents

Abstract

PURPOSE:To simplify the constitution of a device by applying an electric field only to an optional liquid crystal pattern of a variable part by an electrode and changing the optical property of the liquid crystal pattern to form a correct shading pattern. CONSTITUTION:A guide plate 18 of a reading system of facsimile or the like is provided with a slit 20 through which the light from a light source 19 is transmitted, and an original 21 is moved along the guide plate 18 in the direction of an arrow. A plate 23 provided with a slit 24 is arranged on an optical axis 22 of the image of the original 21, and a shading device 13 is arranged between a lens 25 and the plate 23, and the optical image from the lens 25 is focused on an image sensor 26. At this time, the electric field is selectively applied to an optional liquid crystal pattern 15 by the electrode of the device 13 preliminarily to change the optical property of the pattern. Thus, a correct shading pattern is formed, and the quantity of light reaching the sensor 26 is controlled by the device to make the sensor output waveform flat.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to shading of a reading system in a facsimile or the like.

[Conventional technology]

A conventional example of a reading system in a facsimile machine, etc. will be explained based on FIGS. 3 passes through the slit 4 provided in the guide plate 2 and illuminates the surface of the document 1.
The array of surfaces is passed through a slit 7 in a plate 6 along an optical axis 5 and is imaged onto an image sensor 9 by a lens 8.

At this time, the amount of light reaching the image sensor 9 is controlled by adjusting the position of the shading plate 10 shown in FIG. 3(a) provided between the original 1 and the lens 8. Therefore, the sensor output waveform 11 shown in FIG. 3(b) before shading can be obtained by using the shading plate 10 cut into a predetermined shape as shown in FIG. 3(a), and the sensor output waveform 11 shown in FIG. A sensor output waveform 12 shown in FIG. 3(c) is obtained.

[Problem that the invention seeks to solve]

However, in such a conventional example, the shading plate is formed into a predetermined shape, so that subtle differences in characteristics of the light source and image sensor cannot be fully absorbed. As a result, there is a point where the sensor output waveform does not become flat and a ghost phenomenon occurs in the received image.

The present invention has been made in order to solve the above-mentioned problems, and its purpose is to provide a high-precision shading device that can reliably respond to changes in the characteristics of light sources, image sensors, etc., and that can perform Tee adjustment in a short time. It is about providing.

[Means for solving problems]

In order to achieve the above object, the present invention forms a variable part by arranging rectangular liquid crystal turns subdivided in the X-axis direction and the Y-axis direction in a mad link shape, and each liquid crystal pattern of the variable part is It is characterized in that electrodes are provided in the X-axis direction and the Y-axis direction, respectively, to apply electric fields.

[Effect]

The present invention having the above-mentioned characteristics forms an IE aging pattern by applying an electric field only to an arbitrary liquid crystal pattern in the variable part using electrodes, thereby changing the optical properties of this liquid crystal pattern.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 and 4.

FIG. 1 is a front view of this embodiment. In the figure, 13 is a shading device, and 14 is the shading device 13.
The glass 15 is a liquid crystal pattern provided in the glass 14, and forms a variable portion 16 and a fixed portion 17. The variable portion 16 has a rectangular liquid crystal pattern 15 subdivided into a plurality of parts.
are arranged in a matrix in the X-axis direction and the Y-axis direction, and the fixed part 17 is arranged adjacent to the variable part 16, and electrodes (not shown) are arranged in the X-axis direction and the Y-axis direction. This allows an electric field to be applied to any of the liquid crystal patterns 15 described above.

FIG. 4 is a block diagram of a reading system including a shading device. In the figure, 18 is a guide plate having a slit 20 through which light from 19 of a fluorescent lamp or the like passes.

Reference numeral 21 denotes an original that moves in the direction of the arrow along the guide plate 18, 22 an optical axis of an image on the surface of the original 21, and 23 a plate in which a slint 24 is provided. 25 is a lens placed behind the shading device 13, and 26 is an image sensor placed behind the lens 25.

Next, to explain the operation of the above structure, the document 21 is moved along the guide plate 18 in the direction of the arrow, and the light from the light source 19 is transmitted through the slit 2 provided in the guide plate 18.
0 to illuminate the surface of the original 21, the surface of the original 21 is passed through the slit 24 of the plate 23 along the optical axis 22, and is forged onto the image sensor 26 by the lens 25.

At this time, an electric field is applied selectively to any liquid crystal pattern 15 using the electrodes of the shading device 13 in advance to change the optical properties of the liquid crystal pattern 15 to form an appropriate shading pattern, and the shading device 13 is used to create an image. The amount of light reaching the sensor 26 is controlled to make the sensor output waveform in a flat state.

In this embodiment, the shading device 13 has a structure that can be used in place of the conventional grading plate 10, but if the shading device 13 has a similar structure to a filter, it can be integrated with the lens. If an enclosed shading device is configured, it can be used as a lens with a shading device.

Furthermore, by using a memory type liquid crystal, it is possible to obtain a power-saving type shading device that does not require power after energizing only the first cent.

〔Effect of the invention〕

As described above, according to the shading device according to the present invention, the variable portion is formed by arranging rectangular liquid crystal patterns subdivided in the X-axis direction and the Y-axis direction in a mad link shape, and each liquid crystal pattern of the variable portion is The electrodes that apply the electric field to
By providing the electrodes in the axial direction and the Y-axis direction, the electric field is applied to only the arbitrary liquid crystal pattern of the variable part using the electrodes, and the optical properties of the liquid crystal pattern are changed. This has the effect of performing highly accurate shading, and since the adjustment is made by applying an electric field to the liquid crystal pattern, the adjustment time can be shortened, and furthermore, the size and weight can be reduced.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of the present invention, and FIG. 2 is a configuration diagram showing a conventional example of a reading system in a facsimile machine 1, 1, etc.
Figure 3(a) is a front view of the shading plate;
Figure (b) is an explanatory diagram showing the sensor output waveform before U shading, Figure 3 (c) is an explanatory diagram showing the sensor output waveform after shading, and Figure 4 is the configuration of a reading system including an embodiment of the present invention. is 1. 13...Noating device 14...Crow 15
...Liquid crystal pattern 16. Variable part patent applicant: Oki Electric Industry Co., Ltd., patent attorney Takashi Kanakura Two-axis 1- 2-

Claims (1)

[Claims] I A variable part is formed by arranging rectangular liquid crystal patterns subdivided in the X-axis direction and the Y-axis direction in a matrix, and electrodes that apply an electric field to each liquid crystal pattern in the variable part are connected to the
The electrodes are provided in the axial direction and the Y-axis direction, and by applying an electric field only to an arbitrary liquid crystal pattern of the variable part, the optical property a of this liquid crystal pattern is changed to form an appropriate noeding pattern. A shading device characterized by: