JPH0573960A - Optical recording sheet - Google Patents

Abstract

PURPOSE:To provide good visibility without glittering in visual recognition, projection of a background and light transmission from behind. CONSTITUTION:This recording sheet has a light reflection layer 3 which reflects light for image recording and erasing and light for image viewing, a light scattering layer 2 which is formed on one surface of the light reflection layer 3 in order to scatter and reflect the light for image viewing and an optical recording layer 1 which is made of a resin contg. a photochromic compd. on the surface of the light scattering layer 2 on the side opposite from the surface formed with the light reflection layer 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reusable optical recording sheet used in an image forming apparatus or the like.

[0002]

2. Description of the Related Art Conventionally, an image forming layer formed of a functional molecule that undergoes a chemical change by temperature and light is provided, and the functional molecule is made flexible by heating.
There is known an optical recording sheet capable of forming an image by irradiating an optical signal according to the image signal and reproducing the formed image. It is classified into a reflection type or a transmission type depending on how the image is reproduced.

As shown in FIG. 4, in a reflection type optical recording sheet, for example, a heating layer for absorbing infrared rays such as carbon black to heat the optical recording sheet is formed on the surface of a substrate 14 such as glass, resin or paper. 13 is provided, and a reflecting layer 12 made of a metal film is provided on the heat generating layer 13. Further, on the reflective layer 12, there is provided a recording layer 11 for image formation, which is made of a resin containing a functional molecule that undergoes a chemical change by temperature and light, and the recording layer 11 is formed on the recording layer 11. A transparent protective substrate 10 made of glass or the like for protecting the substrate is provided.

When an image is formed on the optical recording sheet having the above-mentioned structure, the exothermic layer 13 is heated by the irradiation of infrared rays so that the functional molecules can change the temperature of the recording layer 11 by light. Raise until Then, an optical signal corresponding to the image signal is emitted from the protective substrate 10 side to form an image on the recording layer 11. When the image thus formed on the recording layer 11 is read, illumination light is emitted from the protective substrate 10 side. The illumination light is reflected from the reflective layer 12 below the recording layer 11, and the reflected light can be made stronger or weaker according to the change in the functional molecules of the recording layer 11, and an image can be read. (For example, Japanese Patent Laid-Open No. 61-176930)

[0005]

However, in the above structure, the reflection layer 12 is directly below the recording layer 11 and the light incident on the recording layer 11 is reflected directly to the recording layer 11 side, so that the light is visually observable. When it is used for a visual document that is directly recognized, there is a problem that the visibility deteriorates due to glare and background reflection.

Further, in the transmissive optical recording sheet, there is a problem that the light is transmitted from the back side and the visibility is deteriorated.

In view of the above problems of the prior art, it is an object of the present invention to provide an optical recording sheet which is free of glare, has no background reflection, has no light transmission from the back, and has good visibility. To do.

[0008]

According to the present invention of claim 1, there is provided a light reflecting layer for reflecting light for recording / erasing an image and light for visually recognizing an image, and a light reflecting layer for scattering and reflecting the light for visually recognizing an image. A light-scattering layer formed on one surface of the reflecting layer, and an optical recording layer formed of a resin containing a photochromic compound on the surface of the light-scattering layer opposite to the surface on which the light-reflecting layer was formed. It is an optical recording sheet.

The present invention according to claim 2 is formed on both surfaces of a light reflecting layer for reflecting the light for image recording / erasing and the light for visually recognizing the image and the light reflecting layer for scattering and reflecting the light for visually recognizing the image. An optical recording sheet having a light-scattering layer and an optical recording layer formed of a resin containing a photochromic compound on each of the surfaces of the light-scattering layer opposite to the surface on which the light-reflecting layer is formed. is there.

According to a third aspect of the present invention, a light-absorbing layer that absorbs light for recording / erasing an image, a light-scattering layer formed on both surfaces of the light-absorbing layer to scatter and reflect light for visual recognition of the image, and An optical recording sheet comprising an optical recording layer formed of a resin containing a photochromic compound on each surface of the light scattering layer opposite to the surface on which the light absorbing layer is formed.

[0011]

According to the present invention of claim 1, the light reflecting layer reflects the light for image recording / erasing and the light for visually recognizing the image, the light scattering layer scatters and reflects the light for visually recognizing the image, and the optical recording layer is Record the image.

According to a second aspect of the present invention, the light reflecting layer reflects light for image recording / erasing and light for visual recognition on both sides, and the light scattering layers on both sides of the light reflecting layer reflect light for visual recognition on the image. Are scattered and reflected, and an optical recording layer on both sides of the light reflecting layer records an image.

According to the present invention of claim 3, the light-absorbing layer absorbs light for image recording / erasing on both sides, and the light-scattering layers on both sides of the light-absorbing layer scatter and reflect light for visual recognition of the image. The optical recording layer on both sides records an image.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments.

FIG. 1 is a sectional view of an optical recording sheet of an embodiment according to the present invention of claim 1. That is, the bottom of the optical recording sheet is provided with the light reflecting layer 3 for reflecting the light for image recording / erasing and the light for visual recognition of the image coming from the upper side, and on the upper side of the light reflecting layer 3. In order to make it easier to visually recognize the image, a light scattering layer 2 for scattering and reflecting the light for image recognition is formed, and on the upper side of the light scattering layer 2,
An optical recording layer 1 for recording an image by heat or light is formed.

Next, a method for manufacturing the optical recording sheet formed as described above will be described.

First, as the light-scattering layer 2, a sheet of light-colored paper, such as white or milky white, or a bright color close to white, or a synthetic resin such as vinyl chloride, polypropylene, or polyethylene is formed. On one surface of the light scattering layer 2, a metal material such as aluminum or a metal compound material is formed into a metal film by a vapor deposition method or a sputtering method, or a metal powder and a synthetic resin are mixed to form a reflection film. Then, the light reflection layer 3 is provided. Then, on the other surface of the light scattering layer 2, a photochromic compound excellent in thermal stability, repeated durability, etc., for example, a diarylethene derivative,
An image forming film, which is a mixture of a polymer compound that gives the diarylethene derivative thermal dependence of quantum efficiency, such as polymethacrylic acid resin or polystyrene, is formed as the optical recording layer 1. By the way, when a photochromic compound is irradiated with light having a short wavelength, for example, a wavelength of 436 nm at a certain temperature or higher, its optical property changes, and as a result, the color changes to black, for example. When a long wavelength light, for example, a wavelength of 577 nm is irradiated to the changed portion at a certain temperature or higher,
Its optical properties are restored and, as a result, the color returns to light yellow transparent. (1-7-20, "Dithienylethenoic anhydride photochromic reaction with temperature dependence in polymer thin film", Toshio Harada, Fumio Tachizono, Kotaro Matsuura, Masahiro Irie, Polymer Preprint (Polyme
r Preprints), Japan vol. 40, No. 3 (1991) reference) Next, the operation of such an optical recording sheet will be described.

First, the optical recording sheet is heated until the temperature at which the photochromic compound of the optical recording layer 1 can be changed by light. As a heating method, for example, contact heating is performed with a heating roller having a heater for heating, or infrared absorption and heating is performed by irradiating the optical recording layer 1 with infrared rays to heat to a predetermined temperature. Next, an image signal for forming an image is converted into an optical signal, laser light having a wavelength of 436 nm, for example, is modulated with the image signal and applied to the optical recording layer 1. A part of the laser light incident on the optical recording layer 1 is consumed by the change of the photochromic compound, and a part of the laser light is transmitted through the optical recording layer 1 and incident on the lower light scattering layer 2. A part of the laser light incident on the light-scattering layer 2 is absorbed or scattered and reflected by the light-scattering layer 2, but since the laser light is convergent light, the proportion thereof is small, and the remaining laser light is light. It is transmitted to the reflective layer 3 and reflected there. The laser light reflected by the light reflection layer 3 travels in the opposite direction to that when the laser light is incident, and while being absorbed and scattered by the light scattering layer 2, the remaining part thereof is re-incident on the optical recording layer 1. A part of the laser light reflected by the light reflection layer 1 and re-incident on the optical recording layer 1 is also consumed for the change of the photochromic compound,
Laser light is effectively used. Then, the laser light corresponding to the image signal changes the color of the photochromic compound that has been changed, for example, turns black, and the photochromic compound that has not been changed does not change its color, for example, remains pale yellow transparent. .. When forming an image as described above, the optical recording sheet may be moved or the laser light source may be moved.

When visually recognizing the optical recording sheet on which an image is formed as described above, the surface of the optical recording layer 1 is irradiated with scattered illumination light. Most of the illumination light incident on the optical recording layer 1 is absorbed at the portion where the photochromic compound changes to black and appears black, and the illumination light is incident on the light scattering layer 2 below at the transparent portion where the photochromic compound does not change. To do. The light-scattering layer 2 is white and has a high reflectance, and the illumination light that has entered the light-scattering layer 2 is scattered light. Therefore, the light that has passed through the light-scattering layer 2 is reflected by the light-reflecting layer 3 and returns. Most of them, including the one, are scattered and reflected to the optical recording layer 1 side. The scattered reflected light is absorbed in a portion where the photochromic compound is changed to black and is not transmitted to the outside, and is transmitted to the outside in a transparent portion where the photochromic compound is not changed and the background looks white, and the light reflection layer 3 There is no glare and the blackened image forming part is easy to see and can be visually recognized. Further, since the light reflecting layer 3 reflects the light coming from behind and does not transmit it to the optical recording layer 1 side, it is not affected by the light on the back side of the optical recording sheet.

Next, when erasing the image formed on the optical recording sheet, first, the optical recording layer 1 is heated to a predetermined temperature in the same manner as when the image is recorded, and the optical recording layer 1 is formed in that state. For example, laser light having a wavelength of 577 nm may be emitted, or scattered light containing light having a wavelength of 577 nm may be emitted. The optical recording sheet from which the image has been erased can be recorded again and can be reused any number of times.

In the above embodiment, the light scattering layer has a function as a substrate, but the light reflecting layer is made of a sheet-like synthetic resin containing metal powder so as to have a function of the substrate, and the light reflecting layer is provided. A light scattering layer may be formed by forming a resin film in which particles that scatter and reflect light, for example, ceramic particles are mixed on the surface of the layer. Alternatively, the light scattering layer may be formed by directly vapor-depositing particles that scatter and reflect light on the surface of the light reflecting layer.

FIG. 2 is a sectional view of an optical recording sheet of an embodiment according to the present invention of claim 2. That is, in the central layer of the optical recording sheet, the image recording from the upper side and the lower side
A light-reflecting layer 3 for reflecting the erasing light and the light for visually recognizing the image is provided, and the light-reflective layer 3 is provided on the upper side and the lower side of the light-reflecting layer 3 for visually recognizing the image for easy visual recognition. Light scattering layers 2 and 6 for diffusing and reflecting the light are respectively formed so as to sandwich the light reflecting layer 3, and on the upper side of the upper light scattering layer 2 and the lower side of the lower light scattering layer 6, respectively. Optical recording layers 1 and 5 for recording an image by heat or light are respectively formed so as to sandwich the light reflecting layer 3 and the upper and lower light scattering layers 2 and 6 between the three layers.

Next, a method of manufacturing the optical recording sheet formed as described above will be described.

First, the upper light-scattering layer 2 is formed of a sheet of light-colored paper, such as white or milky white, or a bright color close to white, or a synthetic resin such as vinyl chloride, polypropylene or polyethylene. On one surface (lower surface in this case) of the light scattering layer 2, a metal material such as aluminum or a metal compound material is formed into a metal film by a vapor deposition method or a sputtering method, or metal powder and a synthetic resin are mixed. The light reflection layer 3 is provided by forming a reflection film by the above. On the lower surface of the light reflecting layer 3, a light-colored paper similar to white or milky white similar to the upper light scattering layer 2 or a synthetic resin such as vinyl chloride, polypropylene or polyethylene is formed in a sheet shape. The light scattering layer 6 is provided. Next, on the surface of the upper light-scattering layer 2 opposite to the surface on which the light-reflecting layer 3 is formed, a photochromic compound such as a diarylethene derivative having excellent thermal stability and repeated durability, and the quantum efficiency of the diarylethene derivative are provided. As the optical recording layer 1, an image forming film in which a polymer compound that gives the heat dependency of, for example, a polymethacrylic acid resin is mixed is formed. Further, the optical recording layer 5 is formed on the surface of the lower light scattering layer 6 opposite to the surface on which the light reflecting layer 3 is formed, in the same manner as the upper optical recording layer 1.

Next, the operation of such an optical recording sheet will be described.

First, the optical recording sheet is heated until the temperature of the photochromic compound in the upper optical recording layer 1 and the lower optical recording layer 5 is changed by light. As a heating method, for example, contact heating is performed with a heating roller having a heating heater incorporated therein, or infrared rays are radiated from both sides of the optical recording layers 1 and 5 to perform infrared absorption heating to heat to a predetermined temperature. Next, for example, laser light sources having a wavelength of 436 nm are provided on the upper side and the lower side of the optical recording sheet, and the image signals for forming respective images are converted into optical signals and modulated with the image signals to emit the upper laser light. The optical recording layer 1 is irradiated, and the lower laser beam is irradiated to the optical recording layer 5. The action of the laser light incident on the optical recording layers 1 and 5 thereafter becomes the same as that of the embodiment of the invention of the above-mentioned claim 1, so that the upper laser light forms an image on the optical recording layer 1 and the lower laser light is formed. The laser light of forms an image on the optical recording layer 5. Further, at this time, even if the upper and lower laser lights are simultaneously operated, the light reflecting layer 3 reflects the upper and lower laser lights and returns them to the respective laser light source sides, so that the optical recording layers on the opposite side are It does not interfere with image formation.

When visually recognizing, for example, the optical recording layer 1 side of the optical recording sheet on which images are formed on both sides as described above,
The surface of the optical recording layer 1 is irradiated with the scattered illumination light. Most of the illumination light incident on the optical recording layer 1 is absorbed by the photochromic compound to turn black and appears black, and the photochromic compound does not change and is incident on the light scattering layer 2 below in a transparent part. .. The light-scattering layer 2 is white and has a high reflectance, and the illumination light that has entered the light-scattering layer 2 is scattered light. Therefore, the light that has passed through the light-scattering layer 2 is reflected by the light-reflecting layer 3 and returns. Most of them including optical recording layer 1
Scattered and reflected to the side. The scattered reflected light is absorbed in a portion where the photochromic compound is changed to black and is not transmitted to the outside, and is transmitted to the outside in a transparent portion where the photochromic compound is not changed and is seen from the optical recording layer 1 side. If
The background looks white and there is no glare from the light reflection layer 3,
The blackened image forming portion is easy to see and can be visually recognized. Also, when visually recognizing the optical recording layer 5 side, the scattered illumination light may be applied to the surface of the optical recording layer 5 in the same manner as described above.

Next, when the image formed on the optical recording sheet is to be erased, first the optical recording layers 1 and 5 are heated to a predetermined temperature in the same manner as when the image was recorded, and in that state the optical recording layer 1, 5 from each side, for example wavelength 577nm
Laser light may be applied, or scattered light including light having a wavelength of 577 nm may be applied. In the case of erasing, the central light reflecting layer 3 reflects the erasing light back in the direction of the light, so that the image on one side can be selectively erased without interfering with the optical recording layer on the opposite side.

In the above embodiment, the upper and lower optical recording layers 1 and 5 of the light reflecting layer 3 are formed so as to change to the same color, but the present invention is not limited to this, and the upper and lower optical recording layers are formed. By changing the properties of the layers, for example, the color that changes such as black color on the upper side and red color on the lower side may be changed, or the recordable temperature may be changed on the upper side and the lower side. ..

FIG. 3 is a sectional view of an optical recording sheet of an embodiment according to the present invention of claim 3. That is, in the central layer of the optical recording sheet, the image recording from the upper side and the lower side
A light-absorbing layer 4 for absorbing the erasing light is provided, and on the upper side and the lower side of the light-absorbing layer 4, for facilitating the visual recognition of the image, the light for visual recognition of the image is scattered and reflected. Light-scattering layers 2 and 6 are formed so as to sandwich the light-absorbing layer 4, and an image is recorded by heat or light on the upper side of the upper light-scattering layer 2 and the lower side of the lower light-scattering layer 6. The optical recording layers 1 and 5 are for the light absorption layer 3, the upper and lower light scattering layers 2,
6 are formed so as to sandwich the three layers formed in 6.

Next, a method for manufacturing the optical recording sheet formed as described above will be described.

First, the upper light-scattering layer 2 and the lower light-scattering layer 6 are made of a sheet of light-colored paper such as white or milky white, or a synthetic resin such as vinyl chloride, polypropylene or polyethylene. Form. A light absorption layer 4 formed by mixing a light absorption material such as carbon with a synthetic resin is sandwiched between the light scattering layers 2 and 6. Next, on the surface of the upper light-scattering layer 2 opposite to the surface on which the light-absorbing layer 4 is formed, a photochromic compound, such as a diarylethene derivative, having excellent thermal stability and repeated durability is provided. An image forming film in which a polymer compound that imparts heat dependency, for example, a polymethacrylic acid resin is mixed is formed as the optical recording layer 1. Further, the optical recording layer 5 is formed on the surface of the lower light scattering layer 6 opposite to the surface on which the light absorbing layer 4 is formed, in the same manner as the upper optical recording layer 1.

Next, the operation of the above embodiment will be described.

First, the optical recording sheet is heated until the photochromic compounds of the upper optical recording layer 1 and the lower optical recording layer 5 reach a temperature that can be changed by light. As a heating method, for example, contact heating is performed with a heating roller having a heating heater incorporated therein, or infrared rays are radiated from both sides of the optical recording layers 1 and 5 to perform infrared absorption heating to heat to a predetermined temperature. Next, for example, laser light sources having a wavelength of 436 nm are provided on the upper side and the lower side of the optical recording sheet, and the image signals for forming the respective images are converted into optical signals and modulated by the image signals to be recorded on the optical recording layer 1. Irradiate 5. The operation of the laser light incident on the upper optical recording layer 1 will be described. Part of the laser light incident on the optical recording layer 1 is consumed for the change of the photochromic compound and part of the laser light is transmitted through the optical recording layer 1. Lower light scattering layer 2
Incident on. A part of the laser light incident on the light-scattering layer 2 is absorbed or scattered and reflected by the light-scattering layer 2, but since the laser light is convergent light, the proportion thereof is small, and the remaining laser light is absorbed. It penetrates to layer 4 and is absorbed there. Therefore, the upper laser light is blocked by the light absorption layer 4, and does not affect the lower optical recording layer 5. Then, by the laser light corresponding to the image signal, the color of the photochromic compound that has been changed is changed to, for example, black, and the color of the photochromic compound that has not been changed does not change, for example, remains pale yellow and transparent. An image is formed on the optical recording layer 1. The lower laser light also forms an image on the lower optical recording layer 5 like the upper laser light, the light absorption layer 4 absorbs the lower laser light, and the laser light is transmitted to the optical recording layer 1 side. It does not interfere with the image formation of the upper optical recording layer 1.

When visually recognizing, for example, the optical recording layer 1 side of the optical recording sheet on which images are formed on both sides as described above, the surface of the optical recording layer 1 is irradiated with scattered illumination light. Most of the illumination light incident on the optical recording layer 1 is absorbed at the portion where the photochromic compound changes to black and appears black, and the illumination light is incident on the light scattering layer 2 below at the transparent portion where the photochromic compound does not change. To do. The light-scattering layer 2 is white and has a high reflectance, and the illumination light incident on the light-scattering layer 2 is scattered light. Therefore, except for the light that has passed through the light-scattering layer 2 and is absorbed by the light-absorbing layer 4, Most of them are scattered and reflected on the optical recording layer 1 side. The scattered reflected light is absorbed in the part where the photochromic compound is changed and turned black and does not transmit to the outside, the scattered reflected light is transmitted to the outside in the transparent part where the photochromic compound does not change, and the background looks white, The blackened image forming portion is easy to see and can be visually recognized. Also, when visually recognizing the optical recording layer 5 side, the scattered illumination light may be applied to the surface of the optical recording layer 5 in the same manner as described above.

When erasing the image formed on the optical recording sheet, first, the optical recording layers 1 and 5 are heated to a predetermined temperature in the same manner as when the image is recorded, and in that state, the optical recording layer 1 and 5 are heated. 5 may be irradiated with laser light having a wavelength of 577 nm, or may be irradiated with scattered light containing light having a wavelength of 577 nm from each side. Even if it is erased, the light absorption layer 4 in the center
Prevents the erasing light from absorbing and transmitting to the opposite side, so that the image on one side can be selectively erased without interfering with the optical recording layer on the opposite side.

In the above embodiment, a light absorbing material such as carbon was used for the light absorbing layer 4, but instead of this, a selective absorbing material that selectively absorbs only the light of the wavelengths of the recording light and the erasing light is used. A light absorption layer may be formed.

Further, in all of the above examples, the photochromic compound may be another photochromic compound instead of the diarylethene derivative, and the polymer compound may be another polymer compound instead of polymethacrylic acid resin or polystyrene.

[0039]

As is clear from the above description, the present invention has the advantages that glare does not occur, the background does not show up, there is no light transmission from behind, and the visibility is good.

Further, since the optical recording layer is formed on both sides of the light reflecting layer or the light absorbing layer, it is convenient because double-sided recording can be selectively performed.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical recording sheet of an embodiment according to the present invention of claim 1.

FIG. 2 is a cross-sectional view of an optical recording sheet of one embodiment according to the present invention of claim 2.

FIG. 3 is a sectional view of an optical recording sheet of an embodiment according to the present invention of claim 3.

FIG. 4 is a sectional view of a conventional optical recording sheet.

[Explanation of symbols]

 1 Optical Recording Layer 2 Light Scattering Layer 3 Light Reflecting Layer 4 Light Absorbing Layer 5 Optical Recording Layer 6 Light Scattering Layer 10 Protective Substrate 11 Recording Layer 12 Reflective Layer 13 Exothermic Layer 14 Substrate

Claims (3)

[Claims] 1. A light-reflecting layer that reflects light for recording / erasing an image and light for visually recognizing an image, and light scattering formed on one surface of the light-reflecting layer to scatter and reflect the light for visually recognizing the image. An optical recording sheet comprising a layer and an optical recording layer formed of a resin containing a photochromic compound on the surface of the light scattering layer opposite to the surface on which the light reflecting layer is formed. 2. A light reflecting layer for reflecting light for recording / erasing an image and light for visually recognizing an image, and light scattering formed on both surfaces of the light reflecting layer for scattering and reflecting the light for visually recognizing the image. Layer, and an optical recording layer formed of a resin containing a photochromic compound on each surface of the light scattering layer opposite to the surface on which the light reflecting layer is formed Sheet. 3. A light-absorbing layer that absorbs light for image recording / erasing, light-scattering layers formed on both sides of the light-absorbing layer for scattering and reflecting light for visual recognition of images, and the light-scattering layers. An optical recording sheet comprising an optical recording layer formed of a resin containing a photochromic compound on each surface opposite to the surface on which the light absorption layer is formed.