JP2956906B2 - Display panel - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a display panel having an arbitrary colored image formed on a substrate. Such a display panel is used, for example, as a tachometer of a vehicle, a dial of a speedometer, and the like.

[Prior art] Characters and numerals on a meter dial are conventionally formed by printing on a resin substrate. Among them, screen printing is often used, in which a printed coating layer can be printed thickly and a deep image can be obtained. ing.

However, image formation by screen printing involves the use of solvent-diluted liquids, which can be used to set up the work environment such as solvent volatilization and splashing, which can lead to contamination of the work environment and fire, or plate clogging and ink viscosity control. There is a problem that time is required and work management requires skill.

Therefore, in recent years, photopolymerizable inks aiming at eliminating the solvent of the ink and shortening the curing time have been proposed. The photopolymerizable ink utilizes the photocurability of the photopolymerizable resin, and has a low viscosity and fluidity before irradiation with light, so that the solvent can be eliminated.

[Problems to be Solved by the Invention] However, the photopolymerizable ink needs to add a reactive diluent (low molecular weight monomer component) in order to adjust the viscosity to be suitable for screen printing, and this is the same as the solvent. It behaves and unreacted substances volatilize over time from the coating film. In addition, since the molecular weight is reduced as a whole, there are problems such as large curing shrinkage, poor adhesion, and lack of flexibility, and high practicality such as high cost.

The present invention has been made in view of the above circumstances, and its object is to eliminate the need to use a solvent or a reactive diluent in production, to improve the working environment, improve workability, and excel in quality. It is an object of the present invention to provide a display panel capable of displaying an image in an arbitrary color.

[Means for Solving the Problems] The configuration of the present invention will be described with reference to FIG. 1. A display panel comprises a base 1 and image layers 2, 3 of arbitrary colors formed on the base 1.
And the image layers 2, 3, and 4 are formed of a colored film-shaped photopolymerizable resin composition containing a dye or a pigment, and the film-shaped photopolymerizable resin composition is formed on the substrate 1. And a predetermined portion thereof is exposed and cured to form an arbitrary image pattern.

The image layers 2, 3, and 4 made of the film-shaped photopolymerizable resin composition are formed by combining a plurality of layers on the substrate 1. In this combination, at least one image layer 4 has a transmission density of 2.0. It has the above-mentioned color hiding properties.

Further, as shown in FIG. 11, a light-transmissive base 1 and a first image pattern formed on the surface of the base 1
A first image layer 2 composed of a film-shaped photopolymerizable resin composition and a film-shaped photopolymerizable resin are provided on a back surface of the substrate 1 at a position facing at least a part of the first image layer 2. The display panel may be provided with a second image layer 2 ′ made of a composition for adjusting the amount of transmitted light.

[Action] The photopolymerizable resin composition is polymerized by light, cured, and firmly adheres to the substrate. Therefore, the photopolymerizable resin composition of a predetermined color is exposed through a negative mask only to a portion where an image is to be formed, and an unexposed portion is removed, whereby an arbitrary image pattern of an arbitrary color is formed on the substrate. Then, by combining this with a predetermined number of colors or a predetermined number of images, an arbitrary colored image can be easily formed.

Further, when the base is made of a light-transmitting material, a transmission type image is obtained by installing a light source on the back surface. If an image layer is formed on each of the front and back surfaces of the base and laminated, a plurality of display images can be obtained. It is a combination of image layers. Therefore, normally only the outermost layer is visually recognized as a reflection type image, but when the light source is turned on, the image becomes a transmission type, and an image in which a plurality of image layers are combined is visually recognized. Can be changed.

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

FIG. 2 shows a dial of a vehicle tachometer to which the present invention is applied, in which numerals, characters, scales, and the like are displayed by combining image layers made of a colored photopolymerizable resin composition. Here, for example, the area W, that is, the numbers and scales and characters of 0 to less than 6 are displayed in white, the areas R of 6 to 8 are displayed in red, and the background B excluding these numbers and scales is displayed in black.

FIG. 1 shows a partially enlarged sectional view of FIG. In the figure, reference numeral 1 denotes a substrate made of a transparent resin such as a polycarbonate sheet or an acrylic plate, and a white image layer 2 made of a white photopolymerizable resin composition is formed on the substrate 1 so as to cover the substrate. . A red image layer 3 made of a red photopolymerizable resin composition is formed on the white image layer 2, and an image pattern corresponding to the numbers and scales of the region R in FIG. 2 is formed. Further, a black image layer 4 made of a black photopolymerizable resin composition corresponding to the background B is formed thereon.

 The method for manufacturing the dial will be described below.

FIG. 3 shows the structure of the colored photopolymerizable resin film F used for forming the image layers 2, 3, and 4. In the figure, on the lower surface of the transparent support F2, a colored photopolymerizable resin composition layer F1 constituting an image layer is formed, and the lower surface of the colored photopolymerizable resin composition F1 is protected by a protective film F3. .

The colored photopolymerizable resin composition layer F1 includes, as base components, coloring materials such as pigments and dyes, a photopolymerizable resin (molecular weight of several tens to several hundreds) and a binder polymer (molecular weight of several hundreds to several tens ), A catalyst (photopolymerization initiator), an auxiliary agent (polymerization inhibitor), etc., and are colored to an arbitrary color by appropriately selecting a coloring material.

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 5 from the viewpoint of visibility, appearance, color density and the like.
5050 μm, preferably 10-15 μm.

The transparent support F2 is provided with a colored photopolymerizable resin layer F1 through the material.
In order to expose the substrate, it is desirable that the substrate has good light transmittance. Specifically, polyethylene terephthalate, polypropylene, polyethylene, polyvinyl alcohol, polyvinyl chloride and the like can be used. The film thickness is usually 10 to 150 μm, preferably 20 to 50 μm.

The protective film F3 protects the colored photopolymerizable resin layer F1 until it is attached to the base 1, and is preferably one that is easily peeled and removed, and specifically, polyethylene and polypropylene are preferable. Usually, the thickness is preferably set to 10 to 50 μm.

Photopolymerizable resin film of each color of white, red and black of the above configuration
FW, FR, and FB were prepared, and a display panel was manufactured according to the process shown in FIG.

First, in step (1), the substrate 1 (0.5 to 1.5 mm thick)
On the upper side, a white photopolymerizable resin film FW is stuck using a laminator 5 while peeling off the protective film FW3, and pressure-bonded.

Next, in step (2), exposure and curing are performed using an active energy ray, for example, ultraviolet ray 6, to form a transparent support layer FW2.
(Step (3)), and a white image layer 2 is formed on the base 1.
(A transmission density of 0.8 to 1.0). Here, an ultra-high pressure mercury lamp was used as an exposure machine. Exposure is 200 for white
500500 mJ / cm ² is preferred.

In step (4), a red photopolymerizable resin film FR was further pressed onto the white image layer 2 while peeling off the protective film FR3. A negative mask 7 corresponding to the region R in FIG. 2 was placed on the red photopolymerizable resin film FR, and after contact exposure (step (5)), the transparent support layer FR2 was peeled off (step (6)). The exposure amount is preferably from 200 to 500 mJ / cm ² .

Subsequently, in step (7), wet development with an alkali or a solvent or dry development is performed to remove non-exposed areas. The development method varies depending on the composition of the colored photopolymerizable resin layer. For example, in the case of alkali development, 1% NaCO ₃
The non-exposed area is dissolved and removed by spraying an aqueous solution. As a result, only the part which has been strongly adhered and cured by the reaction of light remains, and a red image layer 3 (transmission density 0.4 to 0.7) corresponding to the number and scale of the region R is formed on the white image layer 2.

Further, in order to form the numbers and scales of the region W and to make the display sharp, and to give it a function as a transmissive display panel, a black photopolymerizable resin film FB is used.
Performed the same process. First, in step (9), the black photopolymerizable resin film FB was pressure-bonded onto the red image layer 3 while the protective film FB3 was peeled off, and a negative mask 8 was placed to perform contact exposure (step (10)). Exposure is about 1000mJ
/ cm ² is preferable.

Next, the transparent support layer FB2 is peeled off (step (11)),
By developing (step (12)), a black image layer 4 (transparent density of 4 or more) is formed, and the display panel having the structure shown in FIGS. 1 and 2 is completed.

By forming an image layer having a concealing property (high transmission density) like the black image layer 4 in this way, the image is visually recognized as a reflection type image in the daytime, and a light source is installed on the back surface of the substrate at nighttime. Numbers and characters transmit light and shine in each color, and the black background portion does not transmit light, so that it can be used as a so-called transmissive image / illumination. In this case, it is desirable to use an image layer having a transmission density of 2.0 or more as the image layer having a hiding property.

The boundary between the image layer having the concealing property and each color is the fifth layer.
As shown in the figure, the concealable image layer 9 and another image layer 10 may be provided in contact with each other, but the edge of the concealable image layer 9 is placed on the other image layer 10 as shown in FIG. A beautiful image without a seam can be formed by superimposing them on the substrate.

Incidentally, the degree of curing tends to slightly decrease by coloring the photopolymerizable resin composition, but in the colored photopolymerizable resin composition constituting the image layer of the present invention, if the degree of curing is about 70% or more, Even if unreacted substances remain, it is considered that there is no effect on the image layer in practical use.

According to the study by the present inventors, the degree of cure and the image quality of the colored photopolymerizable resin composition show a tendency as shown in FIG. Here, the image quality is a color maintaining power, light resistance, adhesion to a substrate, film hardness, heat resistance, heat cycle resistance, and the like.
A practically usable image quality can be obtained with a curing degree of 70% or more.

Then, a colored photopolymerizable resin composition having a film thickness of 10 to 15 μm (thickness of 15 μm
About 1.3), image layers having various degrees of curing were formed by changing the exposure amount and the like (the relationship between the degree of curing and the film hardness at this time is shown in FIG. 8). The durability test was carried out under the conditions shown in Table 1 for the image layers having the respective curing degrees (50%, 70%, 100%). In the evaluation, if all of the check items are satisfied under each test condition,
When at least one was not satisfied, it was evaluated as x, and the results are shown in Table 1.

As shown in the table, if the degree of cure is about 70% or more,
As a display image layer, high image quality that can withstand long-term use can be realized. Further, it is sufficiently possible to obtain a curing degree of 100% by optimizing the film thickness, the coloring concentration, the exposure amount and the like.

Alternatively, as in this example, if the substrate is light-transmitting, after forming an image layer, the substrate is exposed again from the back surface side,
The degree of curing can be further improved. In some cases, light does not reach the lower part of the image layer by exposure only on the display surface side.However, by performing re-exposure through a light-transmitting substrate, the unreacted portion of the photopolymerizable resin is reduced, and the degree of curing is reduced. improves.

FIG. 9 shows a second embodiment of the present invention. In this embodiment, the base 1 and the lowermost image layer (here, the white image layer 2)
Between the adhesive layer 11 made of a transparent photopolymerizable resin composition
Is provided. Other configurations are the same as those in the first embodiment. Since the adhesive layer 11 is transparent and contains no dye or pigment,
The degree of curing is higher than that of the colored one, and the adhesion between the image layer and the substrate is enhanced. By combining exposure from the back side, the adhesion between the image layer and the substrate can be further strengthened, and a display panel having excellent processing resistance when drilling and assembling to a display panel can be obtained. The thickness of the adhesive layer 11 is usually
It is desirable that the thickness be about 0.1 to 100 μm. Especially 5-10μ
About m is preferable.

FIG. 10 shows the adhesion improving effect of this embodiment. The figure also shows the results of the case where only the display surface is exposed and the case where the back surface is exposed again in the configuration of the first embodiment. As is clear from the figure, although the configuration of the first embodiment can provide practically sufficient hardness, it can be seen that the adhesion is dramatically improved by providing an adhesive layer by backside exposure.

 FIG. 11 shows a third embodiment of the present invention.

In this embodiment, the dial of the tachometer for the vehicle shown in the first embodiment (see FIGS. 1 and 2) has
Images for adjusting the amount of transmitted light shown in FIG. 12 are stacked, and the brightness of the displayed image is prevented from being uneven by the light source installed on the back of the display panel.

The image for adjusting the amount of transmitted light (FIG. 12) is obtained by sequentially forming a white image layer 2 'of a predetermined pattern and a black image layer 4' on the lower surface of a base 1 'made of a transparent resin.
An image pattern is formed as shown in the figure. In the figure, a region B corresponds to a black image layer, a region W corresponds to a white image layer, and a light source is a region B.
It is installed almost in the center. The region C is configured such that the concealing property decreases as the distance from the light source increases, and the region C is relatively far away.
Does not form an image layer, and the transparent substrate is exposed. This image pattern is appropriately changed depending on the brightness of the light source and the position composition.

When manufacturing a display panel having the above structure, each base 1
Image layers 2, 3, and 4 (2'4 ') are formed on (1'), respectively, and reexposed from the back surface to improve the film hardness. If the adhesive layer shown in the second embodiment is provided, it is possible to further improve the adhesion. Thereafter, the substrate 1
The base 1 'is fixed by pasting or bolting so as to be in close contact with each other to obtain a finished product.

As described above, in the present invention, a display panel may be configured by laminating a plurality of substrates on which an arbitrary image layer is formed, and changing the displayed image between the reflective type and the transmissive type. Is also possible. For example, if a decoration image serving as a background is arranged between the character image and the light amount adjustment image, only the outermost character image is visible as a reflection type in the daytime, but when the light source is turned on, the background is added to the character image. Image and a display panel with high decorativeness can be obtained.

In the present invention, the surface of the image layer is roughened, and a glossy image can be obtained by suppressing the glossiness.
When viewed as a reflection type image, it is possible to provide light prevention on the image surface, a sense of calmness in color tone, and the like. As a method for this, the contact surface of the colored photopolymerizable resin film with the colored photopolymerizable resin composition layer of the transparent support is previously roughened, or the surface is hot pressed after the image layer is formed. It can be realized by roughening the surface. For example, by changing the roughness of a transparent support (polyethylene terephthalate; PET), as shown in FIG.
It can be reduced to 11% (the roughness of the transparent support is 0.5 μm) and 2% (the roughness of the transparent support is 2-3 μm).

In the above embodiment, the image is composed of three colors of white, red and black, but the display panel of the present invention is not limited to this.
Films having any color can be arbitrarily combined. If the display panel is not a transmissive display panel, the substrate does not need to be made of a transparent resin, and may be colored.

[Effects of the Invention] Since the display panel of the present invention has an image composed of a colored film-form photopolymerizable resin composition, it can be formed into an arbitrary colored image simply by sticking it to a substrate and curing a predetermined portion. Therefore, there is no need to prepare a printing plate as in the related art, and no ink is required. Therefore, problems such as viscosity control of the ink, contamination of the working environment due to evaporation of the solvent, and clogging of the plate do not occur. Furthermore, it is possible to form a high-resolution image compared to the conventional method (up to about 50 lines by the screen printing method,
100 lines or more are possible), and it is also possible to express shades of color that were not possible with the screen printing method.

In addition, since the base is made of a highly permeable material and has a laminated structure, various images can be displayed, and a display panel excellent in aesthetic appearance and decorativeness can be obtained. In addition, the steps of forming image layers on a plurality of substrates are performed in parallel, and thereafter, the layers may be laminated and integrated to facilitate the production. Further, by performing re-exposure from the back surface side of the substrate, the degree of curing of the image layer can be improved and the adhesion between the image layer and the substrate can be ensured, so that the durability is remarkably improved.

[Brief description of the drawings]

1 to 8 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 a partially enlarged cross-sectional view of a colored photopolymerizable resin film for forming an image layer used in this example, FIG. 4 is a diagram showing a dial manufacturing process,
5 and 6 are partially enlarged cross-sectional views of the image layer boundary portion of the dial, FIG. 7 is a diagram showing a relationship between the degree of curing of the colored photopolymerizable resin composition and image quality, and FIG. 8 is a degree of curing. FIG. 9 to FIG. 10 are diagrams showing the relationship between the film hardness and the second embodiment of the present invention,
FIG. 9 is a partially enlarged sectional view of the display panel, FIG. 10 is a diagram showing the effect of improving the adhesion by the present embodiment, and FIGS. 11 to 13 show a third embodiment of the present invention. FIG. 11 is a partially enlarged sectional view of the display panel, FIG. 12 is a partially enlarged sectional view of the transmitted light amount adjusting image, and FIG. 13 is a front view of the transmitted light amount adjusting image.
The figure shows the relationship between the roughness of the transparent support and the gloss. 1, 1 '... base 2, 2' ... white image layer 3 ... red image layer 4, 4 '... black image layer

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshio Koura 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References JP-A-62-267738 (JP, A) JP-A-60- 212098 (JP, A) Japanese Utility Model Showa 62-193517 (JP, U) JP-B 54-15691 (JP, B2) JP-B 55-28741 (JP, B2) JP-B 53-37212 (JP, B2) JP-B-55-29780 (JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01D 13/02

Claims (4)

(57) [Claims] An image forming apparatus comprising: a substrate; and an image layer of an arbitrary color formed on the substrate, wherein the image layer is composed of a colored film-shaped photopolymerizable resin composition containing a dye or a pigment, A display panel wherein the film-shaped photopolymerizable resin composition is disposed on the substrate, and a predetermined portion thereof is exposed and cured to form an arbitrary image pattern. 2. The display panel according to claim 1, wherein said image layer comprising said film-like photopolymerizable resin composition is formed by combining a plurality of layers on said substrate. 3. The display panel according to claim 2, wherein in the combination of the film-like photopolymerizable resin composition, at least one layer has a color concealing property having a transmission density of 2.0 or more. 4. A light-transmitting substrate, a first image layer made of a film-like photopolymerizable resin composition for forming a first image pattern on the surface of the substrate, A second image layer for adjusting the amount of transmitted light, which is formed of a film-shaped photopolymerizable resin composition, is provided at a position opposite to at least a part of the first image layer on the back surface. Display panel.