KR101501525B1 - Color tunable mechanoluminescent composite film and method for tuning color of the same - Google Patents

Abstract

Disclosed is a composite film which emits light in a mechanically controllable color system, and a method of controlling the color. Embodiments of the present invention are made up of a mixture of at least two stress-emitting materials emitting light by the applied mechanical energy and a stress-transferring material for transferring mechanical energy externally applied to the stress-emitting material, The first luminescence spectrum of the first stress luminescent material and the second luminescence spectrum of the second stress luminescent material are different from each other among the two or more stress luminescent materials.

Description

TECHNICAL FIELD [0001] The present invention relates to a mechanical light-emitting composite film and a color tunable mechanical colorimetric composite film,

The present invention relates to a light-emitting composite film, and more particularly, to a composite film which emits light in a mechanically controllable color and a method for controlling the color.

The phenomenon of light emission in a mechanical manner, that is, light generated by applying a force to a material has been known for a long time under the name of mechanoluminescence (mechanical luminescence; triboluminescence, fractoluminescence, deformation-luminescence etc.) Is not only uncertain, but is also treated as an academic interest.

For example, X-ray emission (Camara et al. Nature 2008) and ultraviolet emission by ultrasound (Eddingsaas et al. Nature 2006) due to scrape tape peeling in a vacuum state have produced a great deal of academic repercussions The possibility of industrial application is very low due to the fundamental problem that light is generated by friction or breakage.

In order to solve these industrial application problems, the Xu group of the Institute of Industrial Science and Technology (AIST) has developed an elastic or plastic deformation in some materials instead of triboluminescence and fractoluminescence caused by the phenomenon of friction or fracture We have tried to apply non-destructive mechanical luminescence phenomenon called deformation luminescence which generates light to some stress sensors.

In order to apply such a mechanical luminescence phenomenon to various practical industries, brightness, lifetime and color control are very important factors. However, until now, due to limitations of materials themselves, many studies have not been conducted. In particular, due to the limitations of the brightness and lifetime (or reproducibility) of the light emitted from the material, there is no development of technology for color control.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for independently controlling two or more kinds of colors by uniformly mixing at least two stress luminescent materials with a stress transmission material.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

According to one aspect of the present invention, there is provided a mechanically light-emitting composite film comprising: at least two light-emitting materials emitting light by mechanical energy applied; Wherein the first luminescence spectrum of the first stress-luminescent material and the second luminescence spectrum of the second stress-luminescent material of the at least two stress-luminescent materials are composed of a mixture of a stress- Respectively.

In one embodiment, the intensities of the first and second luminescence spectra can be independently adjusted based on the amounts of the first and second stress luminescent materials.

In one embodiment, as the mixing ratio of the first stress luminescent material and the second stress luminescent material is changed, the color expressed in the mechanical light emitting composite film can be adjusted.

In one embodiment, the color expressed in the mechanical light emitting composite film can be adjusted as the delivery period of the mechanical energy applied to the first and second stress luminescent materials is changed.

In one embodiment, the stress transfer material is an elastic organic material having a transmittance of 80% or more in a visible light region. The elastic organic material may include polydimethylsiloxane (PDMS), silicone rubber, UV curable epoxy As shown in FIG.

As described above, according to the embodiment of the present invention, it is possible to expand the application field of the mechanical luminescence phenomenon that has been limited to existing academic research as an industry. The embodiments of the present invention can be applied to illumination and display through color control, and also to bio-imaging such as artificial skin and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating an internal configuration of a mechanical light emitting composite film capable of color adjustment according to an embodiment of the present invention. FIG.
2 is a graph showing spectral characteristics of light generated in a composite film according to the present invention at a tensile-restoring rate of 200 cpm (cycle per minute); Fig.
3 is a view for explaining an aspect in which a luminescent color is changed according to a composition ratio of a stress-stimulated luminescent material constituting a composite film according to the present invention.
4 is a view for explaining an aspect in which a spectrum changes according to a composition ratio of a stress-stimulated luminescent material constituting a composite film according to the present invention.
5 is a view for explaining an aspect in which a luminescence spectrum is changed when a generation period of a stress applied to a stress luminescent material constituting a composite film according to the present invention is changed.
6 is a view for explaining an aspect in which a luminescence spectrum is changed when changing the generation period of a stress applied to a stress luminescent material in various composition ratios of a stress luminescent material constituting a composite film according to the present invention.
FIG. 7 is a view for explaining a method of manufacturing a composite film including a character pattern having various colors shown in FIG. 8; FIG.
FIG. 8 illustrates a composite film including a character pattern having various colors according to an application example of the present invention. FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating an internal configuration of a color light controllable mechanical light emitting composite film according to an embodiment of the present invention; FIG.

As shown in FIG. 1, the mechanical light-emitting composite film which can be used in the present invention includes at least two light-emitting materials emitting light by mechanical energy applied thereto, and a light- Of the stress-transferring material. Here, the first luminescence spectrum of the first stress luminescent material and the second luminescence spectrum of the second stress luminescent material are different from each other among the at least two stress luminescent materials.

That is, according to the embodiment of the present invention, the principle of independently controlling two kinds of colors by uniformly mixing two kinds of stress luminescent materials with an elastic organic material (stress transmission material) is used.

In FIG. 1, the two stress relieving materials include copper-doped zinc sulfide (hereinafter, referred to as Zns: Cu) which expresses green light and zinc sulfide doped with copper or manganese (Hereinafter referred to as PDMS) is used as the stress transmission material for transmitting the stress to the light emitting material, but the present invention is not limited thereto.

In another embodiment, the stress relieving material may be ZnS: Mn, ZnS: Cu, Mn, ZnS: Cu, Pb, ZnS: Cu, Pb, Mn, MgF2: Mn, La2O2S: Eu, Y2O2S: Cu, EuD4TEA, EuD4TEA Eu, Sr2MgSi2O7: Eu, Sr2MgSi2O7: Eu, Ca2MgSi2O7: Eu, Sr2MgSi2O7: Eu, Sr2MgSi2O7: Eu, Sr2MgSi2O7: Eu, (Ba, Ca), TiO3: Pr3 +, ZnGa2O4: Mn, MgGa2O4: Mn, Ca2Al2SiO7: Ce, ZrO2: Ti, ZnS: Mn, Te, Materials) include optically transparent (transparency of 80% or more in visible light region) including PDMS, and durable silicone rubber or UV curable epoxy can be widely used.

Further, the inventive concept of the present invention can be found in a wide range of color control by using a light emitting material which can display various emission colors that can be displayed on a color coordinate system without being restricted to only the material which expresses green and red light .

In order to manufacture a composite film capable of color adjustment according to an embodiment of the present invention, it is necessary to ensure an improved mechanical light emission intensity and a material characteristic of a life span. For this, in the embodiment of the present invention, a transparent PDMS having a very strong elastic force and durability can be used as a stress transmission material.

The PDMS has the following three advantages as a stress transmission material.

1. PDMS does not adhere to the stress luminescent material when it is mixed with the stress luminescent material because of its low interfacial free energy. When the stress-emitting material and the stress-transferring material are strongly adhered, the interfacial state may be broken as the adhesive surface slips under various deformation conditions. In the case of PDMS, the surface of the stress-emitting material is not adversely affected, Stress can be transmitted.

2. Because PDMS is optically transparent, the mechanically emitted light can be transmitted to the outside without loss of light.

3. Because PDMS is durable, it does not break even if repeated stress is applied for a long time.

FIG. 2 is a graph showing spectral characteristics of light generated in the composite film according to the present invention at a tensile-restoring rate of 200 cpm (cycle per minute).

As shown in Fig. 2, the mechanical emission spectrum of green light in ZnS: Cu stress light emitting material and the mechanical light emission spectrum of red light in ZnS: Cu and Mn stress light emitting material are observed by the externally applied mechanical energy.

As one embodiment for adjusting the color of light emitted from the composite film having the above-mentioned configuration, a method of changing the composition ratio of two or more stress-emitting materials constituting the composite film is proposed. In actual experiments, the Zns: Cu and the ZnS: Cu and Mn were mixed in a ratio of red: green (O: G) in the ratio of 10: 0, 9: 1, 8: 2, 7: : 4, 5: 5, 0:10. The ratio of PDMS to the total luminescent material was maintained at 7: 3.

A stretching-releasing system was used to observe the optical properties of the mechanical luminescence emitted from the composite film, and the results are shown in FIG.

3 is a view for explaining an aspect in which a luminescent color is changed according to a composition ratio of a stress-stimulated luminescent material constituting a composite film according to the present invention. As shown in FIG. 3, as the ratio of G (green) increases at the ratio of O: G, the color of light emitted from the composite film changes from red to green. As shown in FIG. 4, the intensity of the spectrum corresponding to the green increases as the G ratio increases.

As another embodiment for adjusting the color of light emitted from the composite film according to the present invention, a method of changing the delivery cycle (or the tensile-restoration rate) of the mechanical energy applied to the composite film is proposed. That is, depending on how fast the stress is applied to the composite film, the color of the light to be developed is changed. This will be described in detail with reference to Figs. 5 to 6. Fig.

5 is a view for explaining an aspect in which the emission spectrum is changed when the generation period of the stress applied to the stress luminescent material constituting the composite film according to the present invention is changed. Referring to FIG. 5, it can be seen that when the tensile-resilience rate increases from 200 cpm to 500 cpm, the emission spectrum shifts to the left. This is because the doping position of Cu in ZnS: Cu is located at various energy levels. That is, as the rate of stress change increases, light of a wavelength range of high energy is emitted.

On the other hand, color control in the composite film according to the present invention may be a combination of the two methods described above. This will be described in detail with reference to FIG. 6 is a view for explaining an aspect in which the emission spectrum is changed when changing the generation period of the stress applied to the stress luminescent material in various composition ratios of the stress luminescent material constituting the composite film according to the present invention.

6 shows the result of indirectly measuring the color change and the spectral change result with respect to the high stress change rate (500 cpm or more) by making the composite film according to the present invention with a thick film inorganic EL and applying an electrical frequency thereto. do.

6, the spectra (a, b, c, d, e, f) of Zns: Cu and Mn are kept constant as the frequency changes, And it is found that it is shifted to the left side. This result means that the light emitted from the color coordinate is blue shifted. In addition, it can be confirmed that the spectrum of the light is changed depending on the composition ratio of 'Zns: Cu, Mn': 'ZnS: Cu' (O: G).

On the other hand, when only Zns: Cu, Mn is used as a stress-stimulated luminescent material, the spectrum is kept constant despite the change of the frequency, since it acts only as a sensitizer in case of Cu in Zn: Cu, Mn , Even though there are various energy levels in Cu, Mn maintains a constant state.

As described above, in the composite film according to the present embodiment, not only the composition ratio of the stress-stimulated luminescent material constituting the composite film, but also the period of the stress applied to the composite film are variously changed to realize a wide color adjustment range.

Examples of application of the above-described characteristics (spectrum ratio depending on the composition ratio or stress generation period) of the composite film according to the present invention are described with reference to Figs. 7 and 8. Fig. FIG. 7 is a view for explaining a method for manufacturing a composite film including a character pattern having various colors shown in FIG. 8, and FIG. 8 is a view for explaining a method for manufacturing a composite film including a character pattern having various colors Fig.

As shown in FIG. 7, a composite film was produced by using a screen printing technique in order to implement characters having various color patterns as shown in FIG. First, a mask for silkscreen printing is formed on a glass substrate in a predetermined pattern, and a paste in which at least two stress-emitting materials are mixed is applied on the mask (a). In FIG. 7, paints (two or more of the above-mentioned stress-stimulated luminescent materials were mixed and mixed) prepared so as to express green, orange, and yellow, respectively, were used.

Next, the applied paint is pushed by a squeegee to impregnate the paint into the mask gap to form a character pattern (b). Then, PDMS is applied as a stress transfer material on the formed letter pattern as a transparent substrate (c), followed by curing for 30 minutes in an environment of 70 ° C (d). Thereafter, when the curing of the PDMS is completed, the glass substrate is separated to complete the composite film (e).

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (10)

At least two stress luminescent materials which emit light by the applied mechanical energy and a stress transfer material which transmits mechanical energy externally applied to the stress luminescent material,
The first luminescence spectrum of the first stress luminescent material and the second luminescence spectrum of the second stress luminescent material are different from each other among the at least two stress luminescent materials,
The color developed in the mechanical light-emitting composite film is controlled as the delivery period of the mechanical energy applied to the first and second stress luminescent materials is changed,
The color expressed in the mechanical light-emitting composite film is controlled as the mixing ratio of the first stress luminescent material and the second stress luminescent material is changed
Wherein the light-shrinkable mechanical light-emitting composite film is characterized by comprising: The method according to claim 1,
The intensities of the first and second luminescence spectra are independently adjusted based on the amounts of the first and second stress luminescent materials
Wherein the light-shrinkable mechanical light-emitting composite film is characterized by comprising: delete delete The method according to claim 1,
The stress transmitting material is an elastic organic material having a transmittance of 80% or more in a visible light region,
The elastic organic material may be at least one of polydimethylsiloxane (PDMS), silicone rubber, and UV cured epoxy
Wherein the light-shrinkable mechanical light-emitting composite film is characterized by comprising: A method of adjusting the color in a mechanical light emitting composite film composed of at least two stress luminescent materials emitting light by the applied mechanical energy and a stress transmission material for transferring mechanical energy externally applied to the stress luminescent material In this case,
The first luminescence spectrum of the first stress luminescent material and the second luminescence spectrum of the second stress luminescent material are different from each other among the at least two stress luminescent materials,
Changing a mixing ratio of the first stress luminescent material and the second stress luminescent material;
And changing the delivery period of the mechanical energy applied to the stress luminescent material
Wherein the light-emitting layer is formed of a light-emitting layer.
delete delete Providing a first stress luminescent material emitting light by an applied mechanical energy and a second stress luminescent material having an emission spectrum different from the first stress luminescent material;
Providing a stress transfer material for transferring mechanical energy externally applied to the first and second stress luminescent materials to form a composite film;
Generating stress on the composite film in a first cycle; And
Changing the stress in the first period to the second period,
The step of providing the stress-
And changing the mixing ratio of the first stress luminescent material and the second stress luminescent material
A method for adjusting the color of a mechanical light emitting composite film.

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