JPH08235343A - Image reader - Google Patents

Abstract

PURPOSE: To read an image having a high contrast and a high definition, to easily handle a device, and to eliminate a bad influence upon a control system and peripheral mechanisms by using a laser light source as the light source of read light. CONSTITUTION: The laser light source like an argon laser 80, a krypton laser, or a helium-cadmium laser is used as the read light source. For example, the argon laser 80 is used as the light source to emit the light whose wavelength is 488nm, and this light beam passes a pinhole 81 and is expanded by a magnifying lens 82. The expanded laser light illuminates the face of a liquid crystal recording medium 20 with a prescribed spread as convergent light by an illumination lens 7. The image of transmitted light modulated by the liquid crystal recording medium 20 is formed on a CCD sensor 75 by an image forming lens 74 and is converted to an electric signal. Thus, image read data having a high contrast and a high definition is obtained. Further, the laser like the argon laser 80 is easily handled and doesn't require a high voltage required for a xenon light source and has no influences upon the control system and peripheral devices.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading device, and more particularly to an image reading device recorded on a liquid crystal recording medium having a polymer-liquid crystal composite layer in which liquid crystal is dispersed and fixed in a resin. .

[0002]

2. Description of the Related Art A polymer-liquid crystal composite is formed, for example, by mixing a liquid crystal and a resin, dissolving them in a common solvent, coating the solution with a spinner or the like, and then evaporating and drying the solvent to form a liquid crystal phase. It is known that the resin phase can be produced by phase separation. As another method for producing a polymer-liquid crystal composite, a liquid crystal and a monomer or oligomer of an ultraviolet curable resin are dissolved in a common solvent, and the mixture of the liquid crystal and the monomer is dried at a temperature at which it becomes an isotropic phase, It can also be produced by subjecting a resin phase and a liquid crystal phase to phase separation by irradiating with ultraviolet rays and polymerizing a monomer.

The state of the phase separation of the liquid crystal phase and the resin phase is such that the liquid crystal phase having a spherical or other shape is dispersed in the resin,
There is a liquid crystal phase in which resin spheres are dispersed. The refractive index in the alignment direction of the liquid crystal phase is adjusted to be substantially equal to the refractive index of the resin. Since the refractive index in the non-aligned state is different from the refractive index of the resin, light is scattered at the interface between the liquid crystal phase and the resin in the non-aligned state immediately after manufacturing the liquid crystal medium, and the transmittance of the medium is lowered. When an electric field is applied to the liquid crystal medium to orient the liquid crystal in the direction perpendicular to the plane of the medium, light is transmitted without scattering.

When a smectic liquid crystal having a memory property is used as the liquid crystal, the alignment state is maintained even if the electric field is removed after the liquid crystal is aligned by applying an electric field. The orientation state is that after cooling by heating to a temperature at which the liquid crystal phase becomes an isotropic phase,
It can be returned to the non-oriented state.

As a method of recording image information on a liquid crystal medium, as shown in FIG. 1A, a corona charger 40 is used to corona-charge the entire surface of the liquid crystal medium 20 to orient the liquid crystal on the entire surface. After that, as shown in FIG. 1B, after heating the recording portion with the thermal head 50 to make the liquid crystal isotropic,
It can be recorded by cooling.

As another method for recording an image on a liquid crystal medium, as shown in FIG. 2, a liquid crystal recording medium 20 in which a transparent electrode 22 and a polymer-liquid crystal composite layer 23 are sequentially formed on a transparent support 21. And the transparent electrode 1 on the transparent support 11 in order.
2. The photosensor 10 having the photoconductive layer 13 laminated thereon is opposed to the photosensor 10 through an air gap, and the photosensor 10 is image-exposed in a state where a voltage is applied between both electrodes by using a power source 30. As a result, the electric field applied to the liquid crystal changes, and by aligning the liquid crystal according to the electric field, it is possible to record image information according to image exposure.

As another method for recording an image on a liquid crystal recording medium using an optical sensor, as shown in FIG. 3, a transparent electrode 12, a photoconductive layer 13, and a dielectric intermediate layer 14 are formed on a transparent support 11. , The polymer-liquid crystal composite layer 23, and the upper electrode 22 are sequentially laminated, the image is exposed to the sensor in the same manner as above, and a voltage is applied between both electrodes.
Image information can be recorded on the liquid crystal layer. In this case, the dielectric intermediate layer 14 may be omitted.

The image information recorded on the liquid crystal medium can be converted into an electric signal by an image reading device as shown in FIG. In FIG. 4, the liquid crystal recording medium 20 is irradiated with illumination light having an appropriate wavelength selected by an optical system including a light source 70, an IR cut filter 71, a bandpass filter 72, and a lens 74. The light transmitted through the liquid crystal medium is adjusted by the imaging lens 75 so as to form an image on the CCD line sensor 75. The liquid crystal recording medium is installed on a movable stage (not shown), and the stage is controlled by a stepping motor so that the transmitted light is CC'd as the stage moves.
Image information is read by converting it into an electric signal by the D sensor. The image signal converted into an electric signal is output to a CRT or a printer as needed.

[0009]

However, when an image is read by the optical system shown in FIG. 4, it is difficult to obtain good image data because the contrast of the liquid crystal medium is low. There is a xenon light source as a light source that can obtain relatively good image data, but it is very difficult to handle. Also,
It is necessary to apply a high voltage to the xenon light source, and there is a problem that noise generated at that time may adversely affect the control system of the image reading apparatus and peripheral devices. The present invention has been made in view of the above circumstances, and provides an image reading device capable of performing high-contrast and high-definition image reading, easy to handle, and not adversely affecting a control system and peripheral devices. The purpose is to

[0010]

In order to achieve the above object, the image reading apparatus of the present invention has an argon laser, a krypton laser, a helium-type laser as a light source for reading.
It is characterized by using a laser light source such as a cadmium laser. Further, the present invention is characterized by comprising a lens for expanding the light from the laser light source through the pinhole and a lens for illuminating the liquid crystal recording medium by converging the expanded light. The present invention also has a layer structure in which a polymer-liquid crystal composite layer is laminated on a photosensor having a photoconductive layer formed on a transparent electrode directly or via a dielectric intermediate layer, and an electrode layer is further formed. And the image is exposed to the photoconductive layer, and a voltage is applied between both electrodes.

[0011]

According to the present invention, laser light is used as a light source for reading a liquid crystal medium, and illumination light close to an ideal point light source is used, whereby high-contrast and high-definition image reading data can be obtained. Lasers such as lasers, krypton lasers, and helium-cadmium lasers are easy to handle and do not require a high voltage such as a xenon light source because they only need to emit light of the wavelength used. It does not affect.

[0012]

The present invention will be described in detail below. FIG. 5 is a diagram showing an embodiment of the image reading apparatus of the present invention. Light having a wavelength of 488 nm is emitted by using the argon laser 80 as a light source, and the beam is expanded by a magnifying lens 82 through a pinhole 81. The expanded laser light is converged by the illumination lens 73 to illuminate the surface of the liquid crystal recording medium 20 with a predetermined spread. The transmitted light modulated by the liquid crystal recording medium is formed by the imaging lens 7
At 4, the image is formed on the CCD sensor 75 and converted into an electric signal.

The argon laser 80 used here is CO
HEREN: Innova 300 series argon ion laser is used, and the pinhole 81 is 20
The thing with a micrometer was used.

[Method for Manufacturing Optical Sensor] An ITO film having a film thickness of 100 nm was formed by vapor deposition on a glass substrate having a thickness of 1.1 mm that had been thoroughly washed to obtain an electrode layer. On the electrode, 3 parts by weight of a bisazo pigment (DPDD-3: manufactured by Dainichiseika Kogyo Co., Ltd.) having the following structure [Chemical formula 1] as a charge generating agent,
Polyvinyl butyral 1 part by weight, 1,4-dioxane 98
1 part by weight and 98 parts by weight of cyclohexane are mixed and dispersed by a paint shaker for 6 hours to prepare a coating solution, and then 100
After drying at 1 ° C. for 1 hour, a charge generation layer having a film thickness of 300 nm was laminated.

[0015]

Embedded image

On this charge generation layer, 3 parts by weight of a compound having the following structure [Chemical formula 2] (DPDT-3: manufactured by Dainichiseika Kogyo Co., Ltd.) as a charge transport agent, a polystyrene resin (Electrochemical Industry Co., Ltd. HRM-3), 2 parts by weight, 1,1,2-trichloroethane (22 parts by weight), and dichloromethane (14 parts by weight) are mixed at 400 rpm for 0.4 seconds with a spinner and then applied at 80 ° C. for 2 minutes. A film having a thickness of 20 μm, which is composed of a charge generation layer and a charge transport layer, is formed by stacking a charge transport layer by drying for an hour
An optical sensor of the present invention having the photoconductive layer of was obtained.

[0017]

Embedded image

[Method for producing liquid crystal recording medium] 4 parts of dipentaerythritol hexaacrylate, smectic liquid crystal S
6 (trade name; manufactured by Merck) 6 parts, fluorine-based activator Florard FC-430 (trade name; manufactured by 3M Company) 0.2 part, photopolymerization initiator “Darocur 1173” (trade name; manufactured by Merck) 0 .2 parts of the mixture was adjusted to 30% solids with xylene.

This solution was applied to an ITO transparent electrode (film thickness of about 500).
ITO on glass substrate with Å, resistance; 80Ω / □)
The side surface is coated with a blade coater having a gap thickness of 50 μm, kept at 50 ° C., and UV of 0.3 J / cm ² is applied.
By irradiating light, an information recording medium having an information recording layer with a film thickness of about 6 μm was produced. A liquid crystal was extracted from the cross section of the information recording medium using hot methanol and dried, and then a scanning electron microscope (manufactured by Hitachi, Ltd., S-800, 10000).
When observing the internal structure, the surface of the layer is 0.6μ.
The inside of the layer is covered with a UV curable resin having a thickness of m.
It was found to have a structure in which resin particles of 1 μm were filled.

A cross section of this liquid crystal recording medium is schematically shown in FIG. In FIG. 6, 21 is a glass substrate, 22 is an ITO transparent electrode, and 23 is a liquid crystal recording layer.

The surface of the liquid crystal recording layer is covered with the skin layer 23-a, which serves to prevent the liquid crystal from seeping out from the surface. The inside of the liquid crystal layer is filled with polymer balls 23-b, and the space between them is filled with a liquid crystal phase 23-c.

[Image Recording Method] The optical sensor manufactured by the above method and the liquid crystal recording medium manufactured by the above method are arranged to face each other with a polyimide film as a spacer via an air gap layer of 10 μm, and an image is formed on the optical sensor. 720V, 40m between exposure so that the photo sensor side becomes positive between both electrodes
When a voltage of sec was applied, it was confirmed that image information corresponding to the subject was recorded on the liquid crystal recording medium.

[Reading of Image] The liquid crystal recording medium on which the image was recorded by the above method was separated from the optical sensor, and the transmitted light was read by the image reading apparatus shown in FIG. 5 and converted into an electric signal.

The liquid crystal recording medium is set on a stage (not shown) movable by a stepping motor (not shown), and C
In accordance with the timing of reading the transmitted light by the CD sensor, the light was moved by a distance corresponding to one pixel and read sequentially.

Reading was performed at 6 × 6 μm / pixel by controlling the moving pitch of the stage and the magnification of the CCD sensor.

When an image obtained from the image data read by the above method was displayed on the display, it was confirmed that the image data with good sharpness was obtained. Further, when a density histogram was created from the image data, the results shown in FIG. 7 were obtained. In FIG. 7, the horizontal axis is the concentration,
The vertical axis is frequency (arbitrary unit). For comparison, image reading was performed using an image reading apparatus using a xenon lamp as a light source as shown in FIG. 4 and the same liquid crystal recording medium as the one used for image reading by the above method. The reading light uses the bandpass filter 72,
Light having a central wavelength of 488 nm and a half width of 25 nm was selected and irradiated onto the liquid crystal medium. Similarly, as a result of displaying the image data on the CRT and comparing the image with the image read using the laser light source, it was confirmed that the image read by the laser has a higher sharpness.

FIG. 8 shows a density histogram obtained from image data obtained by reading an image using a xenon lamp as a light source. Comparing FIG. 7 and FIG. 8, it can be seen that when the laser light is used as the light source, the density range of the density histogram is wider and the image signal has a larger contrast.

Although the argon laser is used as the light source in the above embodiment, the same effect can be obtained by using another laser such as a krypton laser. Further, in the above-mentioned embodiment, the image reading for the separate type liquid crystal recording medium has been described, but the same effect can be obtained by applying the image reading for the integrated type liquid crystal recording medium as shown in FIG.

[0029]

As described above, according to the present invention, a laser beam is used as a reading light source and an ideal point light source is used, whereby a high-contrast and high-definition image reading can be performed, and an argon laser is used. Lasers such as a krypton laser and a helium-cadmium laser are easy to handle and do not require a high voltage such as a xenon light source at the time of lighting, so that it is possible to prevent the control system and peripheral devices from being adversely affected.

[Brief description of drawings]

FIG. 1 is a diagram showing an image recording method using corona charging and heating.

FIG. 2 is a diagram showing an image recording method by voltage application exposure.

FIG. 3 is a diagram showing an image recording method for an integrated liquid crystal recording medium.

FIG. 4 is a diagram showing a conventional image reading device.

FIG. 5 is a diagram showing an image reading apparatus according to the present invention.

FIG. 6 is a diagram showing a configuration of a liquid crystal medium.

FIG. 7 is a diagram showing a histogram when read by the image reading apparatus of the present invention.

FIG. 8 is a diagram showing a histogram when read by a conventional image reading device.

[Explanation of symbols]

10 ... Optical sensor, 20 ... Liquid crystal medium, 21 ... Glass substrate,
22 ... Transparent electrode, 23 ... Liquid crystal recording layer, 23-a ... Skin layer, 23-b ... Polymer ball, 23-c ... Liquid crystal phase, 8
0 ... Argon laser, 81 ... Pinhole, 82 ... Condensing lens, 73 ... Magnifying lens.

Claims (3)

[Claims] 1. An image reading apparatus for reading an image recorded on a liquid crystal recording medium having a polymer-liquid crystal composite layer in which a liquid crystal is dispersed and fixed in a resin, wherein a laser light source is used as a light source of the reading light. Reader. 2. The image according to claim 1, further comprising a lens for expanding light from a laser light source through a pinhole, and a lens for illuminating a liquid crystal recording medium so as to converge the expanded light. Reader. 3. The device according to claim 1, wherein
The polymer-liquid crystal complex layer has a layer structure in which an electrode layer is formed by being laminated directly on a photosensor having a photoconductive layer formed on a transparent electrode or via a dielectric intermediate layer, and An image information reading apparatus characterized by performing image exposure on a photoconductive layer and applying a voltage between both electrodes.