JP2674240B2 - Display panel and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a display panel on which an arbitrary colored image is formed on a substrate. Such a display board is used, for example, as a tachometer of a vehicle or a dial of a speedometer.

[Prior Art] The letters and numbers on the meter dial are conventionally formed by printing on a resin substrate. Among them, screen printing is often used because it allows the printed film layer to be printed thick and provides a deep image. Has been done.

However, in image formation by screen printing, since the ink used is a solvent-diluted liquid, there is a risk of work environment pollution due to solvent volatilization, fire hazard, plate clogging, and ink viscosity control. There is a problem that it requires skill and skill in work management.

Therefore, in recent years, photopolymerizable inks have been proposed aiming at making the ink solvent-free and shortening the curing time. The photopolymerizable ink utilizes the photocurability of a photopolymerizable resin. Since it has low viscosity and fluidity before light irradiation, it can be solvent-free.

[Problems to be Solved by the Invention] However, in the photopolymerizable ink, it is necessary to add a reactive diluent (a low molecular weight monomer component) in order to adjust the viscosity to a value suitable for screen printing. Behavior is exhibited, and unreacted substances volatilize over time from the coating film. Further, since the molecular weight is low as a whole, there are problems that curing shrinkage is large, adhesiveness is poor, and flexibility is poor, and the cost is high, so that practicality is not sufficient.

In addition, multicolor printing is also desired to improve the appearance and visibility of the dial, but in the case of current screen printing, as many plates and inks as the number of colors are required, which makes the process more complicated and costly. It will result in ups.

On the other hand, in the printing industry, offset printing is used as a mainstream of multicolor printing, but when this offset printing is used for a display board, the ink is in a liquid state,
Problems such as poor color density per plate will occur.

The present invention has been made in view of the above circumstances, and its purpose is to eliminate the need to use a solvent, a reactive diluent, or the like in production, improve the work environment, improve workability, and have excellent quality. Another object of the present invention is to provide a display panel capable of displaying an image in any color and a manufacturing method thereof.

[Means for Solving the Problem] The display board of the present invention is formed in a dot shape by being held by a substrate, a transparent photopolymerizable resin layer provided on the substrate, and the transparent photopolymerizable resin layer. And an image layer composed of at least one colored photopolymerizable resin composition layer.

The image layer is formed, for example, on the surface of the transparent photopolymerizable resin layer that faces the substrate, and the display board having such a structure displays a predetermined image on at least the colored photopolymerizable resin film supported by the support. An image forming step of forming a predetermined dot-shaped colored photopolymerizable resin layer on the support by exposing through a negative, and the uncured transparent photopolymerizable resin layer formed on the substrate An image layer forming step of forming an image layer by transferring the dot-shaped colored photopolymerizable resin layer to the surface facing the substrate, and exposing and curing the transparent photopolymerizable resin layer having the image layer. And a holding step of holding the image layer.

The transparent photopolymerizable resin layer is made of at least one of urethane acrylate, epoxy acrylate, and polyol acrylate, and has a film thickness of 0.5 to 20 μm.
It is preferable that The colored photopolymerizable resin layer is composed of at least three colors of yellow, magenta, and cyan,
The image layer is formed as a composite layer of these colored photopolymerizable resins.

[Function] The colored photopolymerizable resin composition is polymerized and cured by light. Therefore, the desired image layer is easily formed by exposing through the negative corresponding to the image to be displayed. Further, the transparent photopolymerizable resin composition holding the halftone dot image layer does not contain a coloring material and easily transmits light, so that a higher degree of curing can be obtained, and therefore a transparent photopolymerizable resin layer is formed. By interposing, the strength of the image layer is improved and the adhesion to the substrate is further improved. Further, as the dot-shaped colored photopolymerizable resin, particularly yellow, magenta, which are the three primary colors,
By using cyan and combining these colors, it is possible to display any color.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a vehicular tachomake dial to which the present invention is applied, in which numbers, letters, scales and the like are displayed by combining four color photopolymerizable resin composition layers of yellow, magenta, cyan, and black. Has been done. Where 0-6
Represents the number of rotations, and the unit is rpm / min.

FIG. 1 shows a partially enlarged sectional view of FIG. In the figure, 1 is a resin base made of a polycarbonate sheet, an acrylic plate or the like, and a transparent photopolymerizable resin layer 2 is formed on the base 1. An image layer 3 made of a colored photopolymerizable resin composition is formed on the transparent photopolymerizable resin layer 2, and an image pattern corresponding to the numbers, scales and the like in FIG. 2 is formed. The image layer 3 is configured as a composite layer of four color photopolymerizable resin composition layers of yellow, magenta, cyan, and black.

 The method of manufacturing the dial will be described below.

FIG. 3 shows the structure of the colored photopolymerizable resin film F used for forming the image layer 3. In the figure, on the upper surface of the support F3, a colored photopolymerizable resin composition layer F1 forming an image layer is formed, and the surface of the colored photopolymerizable resin composition layer F1 is protected by a protective film F2. There is.

The colored photopolymerizable resin composition layer F1 includes, as basic components, a coloring material such as a pigment and a dye, a photopolymerizable resin (molecular weight tens to thousands) as a film-forming component, and a binder polymer (molecular weight tens to tens of thousands). 10,000), a catalyst (photopolymerization initiator), an auxiliary agent (polymerization inhibitor), etc., and by appropriately selecting a colorant, it is colored in each color of yellow, magenta, cyan and black.

The density of each color was set as follows according to the density range of the screen printing ink on the meter dial.

Yellow ink …… 0.1 to 0.6 Magenta ink ...... 0.2 to 0.7 Cyan ink ...... 0.3 to 1.0 Black ink ...... 0.8 to 3.5 In addition, the density is set to 0 by using the transmission densitometer made by Dainippon Screen. Was measured without a filter.

As the photopolymerizable resin, for example, urethane acrylate, epoxy acrylate, polyol acrylate and the like can be used, and urethane acrylate is particularly preferably used. Further, as the binder polymer, an acrylic polymer is more preferable than its film property and sticking property. The film thickness is usually 0.5 to 20 μm, preferably 1 to 10 μm in view of color density, ease of exposure / development, aesthetics of images, and the like.

The composition components of the transparent photopolymerizable resin layer 2 are almost similar to those of the colored photopolymerizable resin layer 1 in which the pigment component is not added.

The support F3 supports the colored photopolymerizable resin layer F1 until it is transferred to the transparent photopolymerizable resin layer 2, and it is desirable that it can be easily peeled off. Specifically, polyethylene terephthalate, polypropylene, Polyethylene, polyvinyl alcohol, polyvinyl chloride, etc. can be used. The film thickness is usually 10 to 150 μm, preferably 20 to 50 μm.

A protective film F2 that can be easily removed by peeling,
Further, since the colored photopolymerizable resin layer F1 is exposed through this material, a material having a good light transmittance is desirable. Specifically, polyethylene and polypropylene are preferable. Generally, the film thickness is preferably 10 to 50 μm.

Prepare yellow, magenta, cyan, and black photopolymerizable resin films FY, FM, FC, and FB having the above-mentioned configurations,
A display panel was produced according to the steps shown in FIG.

First, in step (1), each film FY, FM, FC,
The FB is exposed through the corresponding image display negatives 41, 42, 43, 44, respectively.

At this time, as the negatives 41, 42, 43 and 44, halftone dot separation negatives prepared in advance using a color separation machine are used. As a result, the original image is color-separated into each color of yellow, magenta, cyan, and black, and at the same time, the halftone-separated negative in which the shade of the color is converted into the size of the halftone dot is obtained.

The exposure is performed with an active energy ray, for example, an ultraviolet ray L. Here, an ultrahigh pressure mercury lamp was used as an exposure device. The exposure dose is preferably 100 mJ / cm ² or more for each color. However,
The light emission wavelength may differ depending on the light source of the exposure machine, and is preferably appropriately selected within the range of 300 to 450 mJ / cm ² .

Next, in step (2), the protective film Y2 is peeled off, and in step (3), non-exposed areas are removed by performing wet development or dry development with an alkali or a solvent. Although the yellow photopolymerizable resin film FY is shown here, the same applies to other films. The developing method varies depending on the composition of the colored photopolymerizable resin layer. For example, in the case of alkaline development, a 1% NaCO ₃ aqueous solution is sprayed to dissolve and remove the unexposed area.

As a result, only the portions that react with light and are firmly adhered and cured remain, and the dot-like photopolymerizable resin layers Y, M, C and B are formed on the respective supports Y3, M3, C3 and B3. (Step (4)).

Then, these dot-shaped photopolymerizable resin layers Y, M, C,
The image layer 3 is formed by transferring B onto the transparent photopolymerizable resin layer 2. As shown in FIG. 5, it is convenient that the transparent photopolymerizable resin layer 2 is formed by pasting on the substrate 1 in advance, and the surface thereof is protected by the protective film 21 to form a substrate film.

In step (5) of FIG. 4, the protective film 21 of the base film is peeled off, and the transparent photopolymerizable resin layer 2 is bonded to the halftone dot-shaped photopolymerizable resin layer Y using the pressure-sensitive transfer machine 5.
M, C and B are sequentially transferred (steps (6) to (9)). As a result, the image layer 3 in which the photopolymerizable resin layers Y, M, C and B are combined is formed on the transparent photopolymerizable resin layer 2. After that, the image layer 3 is irradiated with ultraviolet rays again.
The transparent photopolymerizable resin layer 2 holding the is cured to complete the dial shown in FIG.

As described above, according to the present invention, by forming the image layer 3 on the transparent photopolymerizable resin layer 2 and holding it, the adhesion of the image layer 3 can be improved and the strength can be increased. Further, by combining the halftone dot-like photopolymerizable resin layers Y, M, C and B as in this embodiment, an image layer of any color can be formed, and further, the image layer 3 is the outermost layer. Since it is exposed to the outside, the depth of color and the calmness can be obtained when viewed with the naked eye.

Further, in particular, in terms of the function of the display panel, a pointer called a pointer is arranged in the center thereof, and a hole for that purpose and an outer diameter cutting by a press punch are performed.

Table 1 shows the adhesive force between the image and the substrate. Here, A is an adhesion of only the substrate 1 and the image layer 3, and B is a display board composed of the substrate 1, the transparent photopolymerizable resin layer 2 and the image layer 3. In addition, the cross-cut test showed that the number of cracks did not occur in 100 pieces.

In addition, the transparent photopolymerizable resin layer 2 must be disposed firmly and without impairing the appearance. That is, when there is uneven thickness of the layer thickness, pinholes, and the like, bubbles and unevenness are generated when the image is attached, which not only impairs the aesthetic appearance, but also may lead to blistering and fluffing of the image when the ambient temperature rises. Further, if the wall thickness is too thick, it may cause a decrease in flexibility after photocuring and a loss of light amount of the light source when viewed as a transmission image. Therefore, considering the above points and considering the material cost and the sticking property (coating property), the transparent photopolymerizable resin layer 2
The thickness is preferably 0.5 to 100 μm, more preferably 1 to 20 μm. Table 2 shows the results. Here, the adhesiveness was evaluated by a cross cut test, the flexibility was evaluated by a bending test, the light transmittance was evaluated by a transmission density measurement, and the sticking property was evaluated by a laminating test.

As shown in FIG. 6, the image layer 3 may be directly formed on the substrate 1 and the upper surface thereof may be covered with the transparent photopolymerizable resin layer 2. With this configuration, it is possible to block ultraviolet rays (sun rays or the like) to some extent, improve the color retention of the image layer 3, and improve the image quality. In this case, it is desirable that the transparent photopolymerizable resin layer 2 be made of a resin having high transparency so as not to reduce the visibility of the image.
Further, in order to improve the light resistance, a resin having a low ultraviolet transmittance may be used, or an ultraviolet absorber or the like may be mixed in the resin.

Further, in the present invention, after the image layer is formed, the surface can be roughened by hot pressing or the like to form a matte type image, which prevents light on the image surface when viewed as a reflection type image, and provides a calm appearance of the hue. Etc. can be given. This can also be achieved by roughening the contact surface of the transparent support with the resin layer in advance and peeling it off without using hot pressing.By changing the surface viscosity, the glossiness can be easily adjusted. Can be controlled.

Although four colors Y, M, C, and B are used as the halftone dot photopolymerizable resin layer in this embodiment, three colors Y, M, and C may be used, and a combination of these three colors may be used. Thus, it is possible to sufficiently express an arbitrary color. However, since it is difficult to express white only by combining these, it is desirable that the substrate has a white color or a color close to white. If the substrate has a color other than white, a white or near-color underlayer Is preferably formed on the substrate. When an image is formed on a transparent substrate, the desired image can be displayed by laminating another white substrate.

7 and 8 show examples of the structure of the display panel depending on the difference in the substrate color. FIG. 7 shows a reflection type image display panel, and FIG. 8 shows a transmission type image display panel.

In any case, the white or white layer is formed so as to be located in the image display direction, that is, on the back side of the image layer 3 when viewed from the recognition body 7. When the substrate 1 is colored such as black or red, it is desirable to form the white layer 6 between the substrate 1 and the transparent photopolymerizable resin layer 2 as shown in FIG. If a transparent substrate is used, is the white layer 6 formed on the back surface of the substrate 1 (7th
(B) and FIG. 7 (a), the image layer 3 held by the transparent photopolymerizable resin layer 2 may be further formed on the back surface of the substrate 1 to provide a double-sided display panel (see FIG. Figure 7 (d)). Further, the white-based layer 6 may be formed on the upper surface of the image layer 3 and the substrate 1 may be arranged on the recognition body 7 side (FIG. 7 (E)), or of course only the configuration of FIG. 7 (A) may be used.
FIG. 7C shows the case where the substrate 1 is white or white-based color. As the white layer 6, of course, Y, M, and
It is possible to use those having the same basic components as those of the colored photopolymerizable resin layers of C and B and changing the coloring material.
In that case, the concentration range is 0.3 to 1.0.

In the transmissive image display panel shown in FIG. 8, since the light from the light source 8 is transmitted, the substrate 1 needs to be light transmissive, and the white layer 6 is provided between the substrate 1 and the transparent photopolymerizable resin layer 2. Is preferably formed (FIG. 8 (a) (b)). Alternatively, the white layer 6 may be formed on the upper surface of the image layer 3 and the substrate 1 may be arranged on the recognition body 7 side (FIG. 8C).

[Effects of the Invention] As described above, in the display panel of the present invention, the image layer is composed of the dot-shaped colored photopolymerizable resin composition, and the dot-shaped image layer is formed as the transparent photopolymerizable resin layer. Because it was held firmly by
It is possible to realize a display panel having excellent adhesion between the image layer and the substrate and having high image quality.

Further, if the image layer is constituted as a composite layer of photopolymerizable resin composition layers of at least three primary colors of yellow, magenta and cyan, an image of any color can be easily formed.

Further, if the production method of the present invention is adopted, it is not necessary to prepare a printing plate as in the conventional case, and ink is not required. Therefore, viscosity control of ink, work environment pollution due to volatilization of solvent, and plate No problems such as clogging occur. Furthermore, if the photopolymerizable resin composition layer is formed into a film, the handling is easy, the work management is easy, and the manufacturing process is easy to automate.

[Brief description of the drawings]

1 to 5 show an embodiment of the present invention, FIG. 1 is a partially enlarged sectional view of a tachometer dial for a vehicle to which the present invention is applied, FIG. 2 is a front view of the dial, and FIG. Is an enlarged cross-sectional view of the photopolymerizable resin film for forming the image layer used in this example, FIGS. 4 (1) to 4 (9) are views showing the manufacturing process of the dial, and FIG. 5 is in this example. An enlarged cross-sectional view of the substrate film used, FIG. 6, FIG. 7 (a) to (e), and FIG. 8 (a) to (c) are partially enlarged cross-sectional views of a display panel showing another embodiment of the present invention. It is a figure. 1 ... Substrate 2 ... Transparent photopolymerizable resin layer 3 ... Image layer Y ... Colored photopolymerizable resin composition layer (yellow) M ... Colored photopolymerizable resin composition layer (magenta) C ... Colored Photopolymerizable resin composition layer (cyan) B ... Colored photopolymerizable resin composition layer (black)

Claims (8)

(57) [Claims] 1. A substrate, a transparent photopolymerizable resin layer provided on the substrate, and at least one kind of colored photopolymerizable resin retained in the transparent photopolymerizable resin layer and formed in a dot shape. A display panel having an image layer composed of a composition layer. 2. The display panel according to claim 1, wherein the image layer is formed on a surface of the transparent photopolymerizable resin layer that faces a surface of the transparent photopolymerizable resin layer facing the substrate. 3. The display panel according to claim 1, wherein the image layer is formed on the surface of the transparent photopolymerizable resin layer on the substrate side. 4. The display panel according to claim 1, wherein the transparent photopolymerizable resin layer is made of at least one of urethane acrylate, epoxy acrylate and polyol acrylate. 5. The transparent photopolymerizable resin layer has a thickness of 0.5 to 2
The display panel according to claim 1, wherein the display panel has a thickness of 0 μm. 6. The display panel according to claim 1, wherein the colored photopolymerizable resin composition layer comprises at least three colors of yellow, magenta and cyan. 7. A predetermined halftone dot-like colored photopolymerizable resin layer is formed on the support by exposing a colored photopolymerizable resin film supported by at least a support through a predetermined image display negative. An image forming step is performed by transferring the halftone dot colored photopolymerizable resin layer to the surface of the uncured transparent photopolymerizable resin layer formed on the substrate facing the substrate. A method of manufacturing a display board, comprising: an image layer forming step of forming; and a holding step of exposing and curing the transparent photopolymerizable resin layer having an image layer to hold the image layer. 8. In the image forming step, the colored photopolymerizable resin film sandwiched between the support and a protective film is formed,
An exposure step of exposing through a predetermined image display negative, a peeling step of peeling the holding film, and a predetermined halftone dot-like colored photopolymerizable resin layer by removing an unexposed portion formed by the exposure step. The method for manufacturing a display panel according to claim 7, further comprising: a halftone dot image forming step of forming