JPH01154120A - Image formation - Google Patents

Abstract

PURPOSE:To express a flickerless extra fine color image with brightness of a hard copy by heating a high polymer layer on an arbitrary color, fixing it from an opaque diffused condition to a transparent condition and forming a desired color image. CONSTITUTION:When the high polymer liquid crystal 11a is provided on the color pattern 12a in a white diffused condition, the whole surface is perceived almost white. Then, for instance, a sole part corresponding to G is heated to the temperature of isotropic condition or higher by means of a thermosensible head or other heating means, and when the heating means is removed, the high polymer liquid crystal layer 11a which is a upper layer of the G part is fixed in the transparent condition. Other parts which are not heated remain white and a green image is perceived on a white ground from the high polymer liquid crystal layer side 11a. Thus, the extra fine color image is obtained with the brightness of the hard copy and the color image is displayed repeatedly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to outputting an image by receiving an image signal output from a floppy disk, an optical disk, a magneto-optical memory medium, a computer, etc., or a facsimile signal or other image signal. The present invention relates to an image forming method for display, and particularly to an image forming method for outputting diversified color images.

[Prior Art] Traditionally, video output from televisions and VTRs, and output from interactions with computers, have been displayed on display monitors such as CRTs and TN (twisted nematic) liquid crystal displays, and documents have been displayed using word processors, facsimiles, etc. High-definition images such as 2 figures have been output and displayed on paper as printed hard copies.

[Problems to be Solved by the Invention] However, although CRTs output beautiful images when outputting the above-mentioned moving images, flickers and scan results due to insufficient resolution impair visibility when it comes to images that remain static for a long time. lower.

Furthermore, although conventional liquid crystal displays such as the above-mentioned TN liquid crystal have achieved thinner devices, they still have problems such as the labor involved in manufacturing them, such as sandwiching the liquid crystal between glass substrates, and the screen being dark. there were.

Furthermore, CRTs and TN liquid crystals have drawbacks such as the fact that they do not have a stable image memory even while outputting the above-mentioned still image, so that beams and pixel voltages must be constantly accessed.

On the other hand, images printed on paper are high-definition,
In addition, although a stable memory image can be obtained, if a large number of images are used, it takes space to organize them, and it is also a waste of resources if a large amount is discarded.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method that can express high-definition color images, which have conventionally been obtained only as hard copies, with the same sharpness as hard copies, and can repeatedly display color images.

[Means to Solve the Problems] The image forming method according to the present invention includes a polymer layer that becomes transparent and opaque by heating or holding at a predetermined temperature, and a color pattern provided adjacent to the polymer layer. This method is characterized in that an arbitrary color image is formed by fixing the polymer layer on an arbitrary color from an opaque scattering state to a transparent state by heating.

As the polymer layer that can be used in the present invention, a material exhibiting thermotropic liquid crystallinity is suitable. Examples of this include so-called side-chain type polymer liquid crystals, in which low-molecular liquid crystals with main chains such as methacrylic acid polymers and siloxane polymers are added in pentant form, and also used in the fields of high-strength, high-elasticity, heat-resistant fibers and resins. Examples include main chain polymer liquid crystals such as polyester-based or polyamide-based liquid crystals.

Furthermore, those having a smectic, nematic, cholesteric, or other phase, discotic liquid crystal, etc. can be used.

Furthermore, a polymer liquid crystal having a phase exhibiting Smc'' by introducing asymmetric carbon into the polymer liquid crystal and exhibiting ferroelectricity may also be preferably used.

Specific examples of polymer liquid crystals will be illustrated below, but the present invention is not limited thereto.

H)! M praise = 18,000 10CH2-CH).

H3 JtCH2-C)n Solvents for coating and forming these films include dichloroethane, DMF, cyclohexane, etc., as well as tetrahydrofuran (T)IF), acetone, ethanol, and other polar or non-polar solvents, or other polar or non-polar solvents such as these. A mixed solvent is used, and these can be selected depending on factors such as solubility with the polymer liquid crystal used, the material of the substrate to which it is coated, wettability with the surface layer provided on the surface of the substrate, and film-forming properties. Needless to say.

[Function] Hereinafter, as a specific example of a polymer liquid crystal, the structural formula (
The basic configuration of the present invention will be explained in detail using a liquid crystal represented by I).

The polymer liquid crystal was dissolved in dichloroethane, and the solution was applied using an applicator onto a polyester-based transparent substrate that had been washed with alcohol.

Thereafter, when it was left in an atmosphere of 95° C. for 10 minutes, a white scattering film was formed. This film thickness was over 10 μm when the wt% of the polymer liquid crystal before coating was 20%.

When the thus obtained white sheet was scanned with a thermal head, the transparent portion was fixed according to the 9-character graphic pattern. When this sheet was introduced onto a black background with an optical density of 1.2, a clear black-on-white display was obtained.

Furthermore, when the sheet was introduced onto an ordinary overhead projector, a clear negative projected image was obtained in which the characters and pattern portions were projected in white.

Next, the entire surface of the sheet on which the above pattern was recorded is
When heated to 90°C and then kept at about 90°C for a few seconds, the entire surface returned to its original white scattering state, and it remained stable even if returned to room temperature, so it was recorded again.

display could be made.

The above phenomenon occurs in a film state below the glass transition point in which the polymeric liquid crystal maintains a stable memory state, a liquid crystal film state in which it can substantially transition to an optically scattering state, and an isotropic state at higher temperatures. It can be controlled because it can take at least three isotropic film states in which the molecules are aligned.

Next, with reference to FIG. 1, the principle process of providing a polymer liquid crystal layer on a transparent substrate and carrying out the image forming method of the present invention will be explained.

In FIG. 1, the above-mentioned scattering state is the state indicated by ■ in the figure. When this is heated to T2 (Tiso = isotropic state transition temperature) or higher as shown in ■a using a heating means such as a thermal head or a laser, and then rapidly cooled, the light transmission becomes almost the same as in the isotropic state as shown in ■ in the figure. The state is fixed. In this rapid cooling state, it is sufficient to naturally dissipate heat from the substrate into the air without using any particular cooling means. This isotropic state is
It is stable at room temperature or room temperature below 〒1 (Tg=glass transition temperature), and is stable as an image memory.

On the other hand, after heating to 72 or more as in ■a, the liquid crystal temperature Tl
-72, for example, for one to several seconds, the scattering intensity increases again during this holding time as shown in (b), and returns to the original scattering state (■) at room temperature, and this state becomes stable below the TI. Retained.

In addition, as shown by ■ in the figure, if the liquid crystal temperature is maintained between 71 and 72 for a period of about 10 milliseconds to 1 second, an intermediate transmission state can be maintained at room temperature in that area. It is also possible to use it as a gradation expression.

In other words, in this example, the transmittance or scattering intensity can be controlled by how long the liquid crystal temperature is maintained at room temperature after being heated to an isotropic state, and it is stable below the TI. It is something that can be maintained. Furthermore, in the above case, the temperature at which the state is returned to the scattering state is faster when the temperature is closer to 2000 within the liquid crystal temperature.
If the liquid crystal is left at the temperature for a relatively long time, even if it is not heated to an isotropic state, regardless of the previous state,
It is possible to return to the scattered state.

In the image forming method of the present invention, a more beautiful image can be obtained by actively adding a factor that makes the scattering state more intense. For this purpose, the above-mentioned polymeric liquid crystal is dissolved in the above-mentioned solvent such as dichloroethane, []MF (dimethylformamide), or cyclohexane, and then applied to the substrate, and the solvent is volatilized, or after it is volatilized. , liquid crystal temperature (75℃~110℃)
It is desirable that a stable optical scattering film has already been formed by keeping it for a certain period of time.

One of the optimal conditions for forming the film is that the amount of polymeric liquid crystal added to the solvent is such that a clear solution or viscous state is obtained after addition and stirring. For example, when a polymer liquid crystal having the above structural formula is dissolved alone in dichloroethane, the wt% concentration of the polymer liquid crystal is 1.
At 0%, the solution is cloudy and micellar, but at a relatively high concentration of about 15% to 25%, a stable, transparent, viscous solution is obtained. This tendency is also observed in combinations with several other types of polymeric liquid crystals and solvents. When this transparent viscous solution is applied to a well-cleaned substrate such as glass or polyester using an applicator, wire bar, or dipping, and maintained at the liquid crystal temperature, the results are lower than when similarly applied in the micellar form. , an optical scattering film with very high uniformity can be obtained.

At this time, the substrate was subjected to non-orientation treatment or was subjected to extraction treatment in multiple directions using ethyl alcohol, etc., and in either case, stains on the surface were considerably eliminated.

As the solvent for the polymeric liquid crystal, it is also possible to add a mixed solvent of a plurality of solvents, a mixture other than the polymeric liquid crystal material, a pigment material, and the like to the extent that it does not adversely affect the coating.

Further, in order to prevent dust from adhering to the back surface of the substrate or the surface of the polymer liquid crystal and from being charged, the back surface and the front surface may be subjected to a weak conductive treatment.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 FIG. 2 is a diagram showing an example of the layer structure of an image carrier for carrying out the image forming method according to the present invention.

In this configuration, colors of blue (B), green (G), red (R), black (BL), or yellow (Y), magenta (M), cyan (C), and black (BL) are applied on the base +3a. A mosaic or striped color pattern is provided as the background 12a,
The polymer liquid crystal layer 11 is placed on this pack ground 12a.
It is formed by applying a as a white scattering layer.

The color pattern described above can be formed into a thick or thin film of 12 lines per mm or more for each color, for example, by a conventionally known printing method such as halftone printing. In this example, this color pattern may be printed directly on the substrate, or may be applied in the form of a film to the substrate.

Next, the polymer liquid crystal as described above is provided by coating, etc. as described above, but at this time, if necessary, a transparent film of polyester resin, aramid, polyimide, etc. is coated or laminated on the color pattern as an intermediate layer. Alternatively, a polymer liquid crystal may be provided thereon. In this case, for the polymer liquid crystal shown by the above structural formula, if the layer thickness is about 2 gm or more, it will become a white scattering layer that can provide a sufficient optical coating effect for the color pattern of the underlying layer, and optimally. It is about 5 gm to 15 lm.

Next, the method of forming a color image in this example will be explained using FIG. In FIG. 3, a stripe pattern of B, G, R, and BL is used as a background 12a as a color pattern.

Here, if a polymer liquid crystal is provided on this color pattern in a white scattering state as described above, the entire surface can be visually recognized as being substantially white. After that, using a thermal head or other heating means, for example, only the part corresponding to G is heated to a temperature higher than the isotropic state, and when the heating means is removed, the polymer liquid crystal layer above the G part is fixed in a transparent state. The other parts that were not heated remain white, and a green image on a white background is visible from the polymer liquid crystal layer side. Similarly, if a polymer liquid crystal layer corresponding to only H and only B is heated, red and blue colors will be visible on a white background, respectively. Also, for example, R,! When a polymer liquid crystal layer corresponding to l-G, G and B, B and R1, or all of R, G, and B is heated, a color that is a mixture of these colors can be seen, but in this example, especially when you want to produce black. A BL stripe pattern was also provided to increase this density.

As an example, a thermal head with 12 dots per 1 mm is used to precisely scan a sheet of the image carrier formed in such a manner that three sets of B, G, R, and BL are each formed per 1 mm, that is, a total of 12 lines per 1 mm. However, when heat was generated every three dots as the heat generating portion corresponding to B, an image was formed whose entire surface appeared almost blue.

The image formed in this example is a color image on a white background, and is usually as clear as a color image drawn on paper.

In this case, a clearer image can be visually recognized by illuminating with appropriate white light from the front polymer liquid crystal side.

Embodiment 2 FIG. 4 shows another embodiment of the layer structure of an image carrier for carrying out the image forming method according to the present invention.

The difference in this configuration from Fig. 2 is that the background 12
Instead of a, transparent B, G, and R color filter patterns 12b are used, and the substrate 13b having the same is also made of a transparent material such as polyethylene terephthalate or glass. Furthermore, in this example, the polymer liquid crystal layer 11b does not need to be particularly white;
As in the previous example, a strong scattering state is sufficient, and if necessary, a dye or the like may be further added.

In this example, as in Example 1, - as an example, l m
Using a thermal head with 12 dots per m, B, G, R
4 pairs per mm each, or a total of 12 per II
As shown in FIG. 5, the sheet of the image carrier is scanned every two dots as a heat generating part corresponding to the green filter in this part. When the polymer liquid crystal is made almost transparent and then projected onto a screen from the substrate side or from the polymer liquid crystal side by transmission or reflection using a conventional overhead projector, green light is projected corresponding to this scanning area, and other The area was almost completely dark. Similarly, B and G.

When the polymer liquid crystal in the portion corresponding to all R was made almost transparent and then projected, a nearly white projected image was obtained.

The image projected in this example is basically a high-contrast negative image, and various color combinations are possible. can produce full-color images.

Note that this image is backlit with a fluorescent lamp, an EL (electroluminescent) panel, etc., and good visibility can be obtained even when viewed directly using transmitted light.

Example 3 A small amount of a laser-absorbing dye given by the structural formula (Et=-C2H5) was added to the polymer liquid crystal layer in Example 2, and a laser scanning system such as a polygon mirror or a galvanomirror (here, By modulating the image using a semiconductor laser (with a central emission wavelength of 830 nm) and selecting and scanning a portion corresponding to a predetermined color, it was possible to make the polymer liquid crystal layer in a predetermined portion almost transparent.

As a result, a transmission (projection) image similar to that shown in FIG. 5 was obtained.

Note that the laser-absorbing dye, etc. can be selected arbitrarily, and by appropriately selecting it in accordance with the emission wavelength of the laser used, the efficiency of heat generation by the dye, etc. can be designed to be good.

Example 4 In the layer structure shown in FIG. 2 of Example 1, the base 1
3a was selected here to be transparent, and the structure was such that the laser could be irradiated from the base side.

Here, for example, the pattern B uses a laser-absorbing dye (such as IR-750 manufactured by Nippon Kayaku Co., Ltd.) whose absorption peak wavelength is around 750 nm, and the pattern G uses a laser whose absorption peak wavelength is around 820 nm. Absorbing dye (
IR-820, etc.), and the R pattern has a laser absorption dye with an absorption peak wavelength around 780 nm (GY
-9, etc.) are provided on the substrate side by printing or the like, or added by mixing a small amount of each into these color patterns.

Therefore, as a laser for irradiating these, the emission center wavelength is 750 nm for each of B, G, or R.
By modulating and scanning a semiconductor laser with a wavelength of around 820 nm or 780 nm according to the selection of each of B, G, and R, heat can be transferred to the corresponding polymer liquid crystal part and the part can be made transparent. can.

In this way, there is greater latitude in the precision of the laser irradiation resist for each color.

Note that for the BL pattern in Figure 2, the polymer liquid crystal corresponding to this part may be made transparent using any of the lasers mentioned above, or it may be irradiated with all of the laser beams mentioned above. or lasers of other wavelengths may be used.

It is also possible to perform image formation in the same manner with the configuration shown in FIG.

Furthermore, in this case, the color pattern may be a random mosaic pattern if each absorbing dye can be designed to be insensitive to other color irradiating lasers.

In all of the embodiments described above, the formed image can be erased by means of holding the image carrier at a predetermined temperature, that is, a temperature at which a liquid crystal phase is obtained, for a predetermined period of time, and image formation can be repeated.

This polymer liquid crystal as described above has sufficient heat resistance and strong film strength, so there is basically no problem in repeated image formation, but if necessary, the surface may be modified to further increase the strength. A N-retaining layer of polyimide, aramid, etc. may be provided by laminating or coating with fluororesin or the like.

FIG. 6 is a block diagram showing an example of the case where the present invention is applied to a projection display device, in which the image carrier belt 21 is
The one shown was used.

In this apparatus, after a predetermined color image is formed on an image carrier belt 21 by a heat-sensitive heater 22, a lens 25
, is projected onto the screen 24 by a projection optical system consisting of a light source 26. Thereafter, the image is maintained at the liquid crystal temperature for a certain period of time by the erasing surface heater 23, and the surface of the image carrier is uniformly erased to an optically scattering state again, in preparation for the formation of the next screen.

In addition, microfilm-sized or slide-sized projection display devices can also be formed using a laser as a writing means.

[Effects of the Invention] As explained above, according to the present invention, it is possible to express a flicker-free, high-definition color image with the same clarity as a hard copy. The present invention can be applied to various devices such as a projection device or a device that uses a color image as an intermediate medium.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between temperature and transmittance (scattering intensity).
2 and 3 are diagrams showing the first embodiment, FIG. 4 and pJS5 are diagrams showing the second embodiment, and FIG. 6 is a configuration diagram of the projection display device. 11a, llb...Polymer liquid crystal layer 12a...Background 12b...Color filter pattern 13a, 1
3b ---Base 21... Image carrier belt 22... Thermal head 23... Erasing surface heater 24... Screen 25... Lens 26... Light source

Claims (4)

[Claims] (1) A method of forming image information using a polymer layer that becomes transparent and opaque by heating or holding at a predetermined temperature, and a color pattern, in which the polymer layer on an arbitrary color becomes opaque by heating. An image forming method characterized by forming an arbitrary color image by fixing from a scattering state to a transparent state. (2) The image forming method according to claim 1, wherein the polymer layer contains a polymer liquid crystal material. (3) The image forming method according to claim 2, wherein the polymer layer transitions to a white scattering state at a liquid crystal temperature. (4) The image forming method according to any one of claims 1 to 3, wherein the color pattern is a color filter pattern.