JPS62116192A - Display material and display device using same - Google Patents

Abstract

PURPOSE:To enable the recording and display of an image in a state being clear and easy to see, by providing a layer formed of a high-molecular recording material which is varied from a transparent state to a non-transparent state by heating and is returned from the non-transparent state to the transparent by cooling the same gradually after heating, and a non-transparent layer. CONSTITUTION:A layer formed of a multicomponent mixture polymer 2 being a high- molecular recording material which is varied from a transparent state to a non- transparent state by heating and is returned from this non-transparent state to the transparent by cooling the same gradually after heating is superposed on a non- transparent layer of a heat-absorbing black substrate 1 which is formed by dispersing carbon black or the like into polyethylene terephthalate or the like. The mixture polymer is in a transparent state (light transmittance is 90% or above) at a temperature t1, and it has two states, i.e. a completely amorphous state and a whitened state (light transmittance is 10% or below) which is a state of phase separation. The two states can be selected easily according to the speed of cooling to the state of temperature t1 after the temperature is raised above the transition point of temperature t2. An image can be recorded by a heating means such as a thermal head 11 or a heat pen 9 on a sheet A and further erased therefrom owing to the properties of the phase- separation layer superposed on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a display material capable of recording and erasing information such as characters by aging due to heat, and a display device using this material.

(Conventional technology) In recent years, information recording has become a new recording material.

There is a device that enables erasing, etc. based on a state change due to a change in the thermal properties of a heat-sensitive material (Japanese Unexamined Patent Publication No. 117140/1983).
Publication No.). This information recording body is formed by laminating a heat-sensitive material on a material such as glass or plastic. When a heat-sensitive material is held at a specific temperature to or higher, its state changes depending on the temperature. That is, the two state transition temperatures tt and t2 (tl<t2
), and after heating and holding at a temperature t2 or higher, the lagoon degree t
When cooled to below 0, the color turns white and becomes the maximum light shielding state. On the other hand, when this whitening heat-sensitive material is heated and maintained at a temperature range of t1 or higher and lower than t2, and then cooled to below to, the heat-sensitive material becomes transparent.

(Problems to be Solved by the Invention) However, since this recording medium is transparent, the heat absorption of only the base material and the heat-sensitive material causes a change in the thermal state of the heat-sensitive material, so that the thermal efficiency from the outside is not good.

Furthermore, since a white image is formed in a transparent recording medium, the contrast of the recorded image is poor and it is difficult to see.

The present invention eliminates the drawbacks of the conventional example described above, has excellent contrast and is easy to see, and even when thermal recording is performed from the display surface, thermal efficiency is improved by the black heat absorber, and images with good contrast are produced using a small amount of heat. The present invention provides a display material that enables the formation of a display material and a device using this material.

(Means for Solving the Problems) The display material of the present invention has a layer made of a polymeric recording material that changes from a transparent state to an opaque state when heated, and returns from the opaque state to a transparent state when slowly cooled after heating. It has an opaque layer. For recording and displaying on this display material, heating means is provided that acts on the polymer recording material layer of the display material, and the recorded image is visually observed from the polymer recording material.

(Example) Fig. 1 shows a recording sheet A which is a display material constituting the present invention.
In Figure 0, which is a cross-sectional view of , the black heat-absorbing base material 1 plays an important role among the features of the present invention. As a specific material, one in which carbon black, titanium black, etc. are dispersed in polyethylene terephthalate or the like can be used. In addition, the multicomponent mixed polymer 2, which is the L polymer recording material, undergoes phase separation by heating means and becomes transparent! Changes from island to white state. The mixed polymer that causes this phase separation is, for example, LC5T type (Lower Cr
1tical 5solution Tempretur
e) Several types of polymer combinations are known as systems exhibiting a phase diagram. For example, polyvinylidene fluoride and polymethyl acrylate, polyethyl acrylate,
Combinations with polymethyl methacrylate, polyethyl methacrylate, etc., and combinations of polycaprolactone and polycarbonate (R, E).

Bernstein et al. Macroso
polystyrene and polyvinyl methyl ether (M, Ban
ket, al, J, polya+, Sci, A
-210P1097~(1972)), styrene-acrylonitrile copolymer and polycaprolactone (L,
P, McMaster Macromolecules
8 P2O3 (1973)), styrene-acrylonitrile copolymer and polymethyl methacrylate
(L, P, McMaster Poly
*Prepr, 15 P254~(197
4)), polyvinyl nitrate and polymethyl acrylate (
Sanbe Akiyama et al., Collection of Polymer Papers 33 P238~ (197
B)), polyvinylidene fluoride and polyvinylmethylketoy (D, R, Paul at, at, Po1y+
s Eng, Sci.

18ρ1225~(1978)), or ethylene-vinegar vinyl copolymer and chlorinated rubber (J, LeHing
well, etc.

al,,PolyllPrepr,,14 P591
3-(1973)) and so on. These mixed polymers are heated to a temperature of 1. In the transparent state (90% or more in light transmission rate)
In this case, there is a completely defective state Y island and a white state (light transmittance of 10
% or less) and has two phase-separated states. These two states can be easily selected depending on the cooling rate to the temperature t1 state after raising the temperature to a transition point of temperature t2. Also, this temperature 1. Since the state has a wide temperature range around room temperature, the sea hA
This phase-separated layer, which does not require any heat insulating means or the like to maintain itself at a constant temperature, is laminated on the base material. Due to the properties of this phase-separated layer, it is possible to record and erase images on the sheet A using a heating means such as a thermal head or a hot pen. Sheet A may be provided with a protective layer 3 for protecting the phase separation layer 2 and further an antireflection layer 4 as a display surface to prevent reflection of light, if necessary.

2 and 3 are schematic diagrams showing a display device B using the sheet described above. This display device B has a display recording sheet 6 (hereinafter abbreviated as recording sheet) in the above-described embodiment in the device exterior 5. This recording sheet 6 is attached to the drive roller 7
It is stretched like an endless belt by a driven roller 8 and is driven intermittently. The rotation direction of each roller can be either left or right, and can be selected depending on recording and erasing conditions.

The image on the image forming sheet 6 is transparent at room temperature (transmittance 90%).
Above), the specific method of recording and displaying on the image forming sheet 6 which becomes opaque (transmittance 10% or less) by heating and quenching may be any heating means.
For example, a thermal pen 9 that has a heater at its pen-shaped tip.
By bringing the image forming sheet 6 into contact with the image forming sheet 6, an image can be directly written and recorded on the image forming sheet 61:. This pen 9 is used so that when it leaves the image forming sheet 6, the internal heater is automatically turned off. Furthermore, a recording device such as a pen-shaped device that utilizes heat generation by a light source can directly capture and display an image on one display surface. On the other hand, it is also possible to form an image of an external signal from a computer, word processor, etc. as a dot pattern using the thermal head 11 or heating means such as a laser. Such a thermal head or the like may be of a fixed type or a scanning type with respect to the sheet 6.

If the above-mentioned recording methods are used in combination, it becomes possible to write on an image recorded and displayed using an external signal using a thermal head, etc., using a thermal pen, etc. Also, with the heating means of these methods, f! 'Recording can be performed from the front or back side of the formed sheet 9. In recording from the phase separation layer 2 side of the image forming sheet 9, heat acts directly on the phase separation layer and further heats the black heat-absorbing substrate 1, so that the thermal efficiency for phase separation is as low as when the substrate 1 is only the transparent sheet. The light-to-heat conversion efficiency is better than that of the conventional one, especially when a light source is used as a heat source, and when a black heat-absorbing substrate is used. Furthermore, as described above, it is possible to record on the image forming sheet A from the back side of the image forming sheet A, that is, from one side of the black heat-absorbing substrate, using these heating means in the same way as from the front side.

In addition, if a sheet coated with Teflon (trade name) is used instead of the anti-reflection layer 3 of sheet A, the surface tension, which is a characteristic of Teflon itself, is small, so it can be displayed using a conventional white pen with good removability. It is also possible to record on a surface and erase it by rubbing. This white pen with good removability uses alcohols, cellosolves, and glycerin as solvents, for example.

Glycols or esters may be used, and in order to easily erase images, a material composed of components such as white pigment titanium oxide in spindle oil or the like may be used.

Note that the opaque layer of the display material of the present invention is not limited to black, but a dark color makes it easier to see the opaque portion of the polymeric recording material. Transparent does not mean that light does not pass through it, but rather that it has some kind of color.

Further, the shape of the display material is not limited to the edge web shape, but may be a cut sheet shape or a plate shape.

(Effect of the invention) By making the base material layer opaque, it is possible to improve the thermal efficiency of the polymer layer that undergoes phase separation due to heat, and it becomes possible to record and display images in a clear and easily visible state. At the same time, it has the effect of increasing thermal efficiency during recording.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged sectional view of a recording sheet which is a display material of the present invention, FIG. 2 is a perspective view of a display device using the recording sheet, and FIG. 3 is a sectional view of this display device. In fig. 1-m-black heat absorption base material layer 2--one phase separation layer 5--
--Device exterior A.6---Display recording sheet 9---
---Thermal pen 1o-----Display part 11----Thermal head 12---Illustrated as erasing part.

Claims (2)

[Claims] (1) A display material that has a layer made of a polymeric recording material and an opaque layer that changes from a transparent state to an opaque state when heated, and returns from the opaque state to the transparent state when slowly cooled after heating. (2) A display material comprising a layer made of a polymeric recording material and an opaque layer that changes from a transparent state to an opaque state by heating and returns from the opaque state to a transparent state again by slow cooling after heating, and this display material and a recording heating source acting on a polymeric recording material.