JP6993608B2 - Transparent screens, video display systems, and methods for manufacturing transparent screens - Google Patents

Description

The present invention relates to a transparent screen, an image display system, and a method for manufacturing a transparent screen.

As a transparent screen used for showcases, exhibition cases for works of art, windows of buildings / showrooms, partitions, etc., the view on the opposite side can be visually recognized from the observer side, and the observer can see the image irradiation device such as a projector. A transparent screen has been proposed that allows the image emitted from the projector to be visually recognized.

Such transparent screens are classified as rear type or front type. The front-type transparent screen scatters and reflects the light emitted from the image illuminating device installed on the same side as the observer side with respect to the transparent screen on the surface of the transparent screen substrate, and the scattered and reflected light. Is configured to be displayed on the surface of a transparent screen as an image. On the other hand, the rear type transparent screen scatters and transmits the light emitted from the image irradiation device installed on the opposite side of the observer side to the transparent screen, and displays the scattered and transmitted light as an image. It is configured.

For example, Patent Document 1 discloses a transmissive transparent screen in which a light scattering layer formed by dispersing a light scattering material (for example, hollow beads) in a transparent binder is formed on an intermediate layer of two transparent substrates. There is.

Japanese Patent No. 4847329

However, since the transparent screen as described above contains a resin binder and a light scattering material in the intermediate layer, the image becomes unclear, the transparent screen becomes cloudy, or the transparent screen looks dark. Therefore, as a whole, the haze indicating the degree of cloudiness tends to be high as an index related to transparency. As a result, since the resin layer has low light resistance, it has a drawback that the color changes due to aged deterioration when used in an environment exposed to sunlight.

Therefore, the present invention provides a transparent screen that has a clear image and maintains high transparency.

A transparent screen, an image display system, and a method for manufacturing a transparent screen that solves the above problems have the following features.
That is, the transparent screen according to the present invention is a transparent screen for displaying an image, and has irregularities on at least one main surface, and the arithmetic roughness Ra on the main surface having the irregularities is 1 nm or more and 500 nm or less. It is composed of a transparent screen substrate having an average length RSm of a roughness curve of 200 nm or more and 5000 nm or less.
With such a configuration, the transparent screen can maintain high transparency. In addition, the image projected from the projector can be clearly displayed on the transparent screen. Here, the "video" in the present specification includes both a "moving image" whose display content changes with the passage of time and a "still image" whose display content does not change with the passage of time.

Further, the maximum height roughness Rz on the main surface having the unevenness is 30 nm or more and 600 nm or less.
As a result, the image projected from the projector can be clearly displayed on the transparent screen while maintaining the high transparency of the transparent screen.

Also, the haze is less than 60% in the wavelength range of visible light.
As a result, the high transparency of the transparent screen can be maintained.

Also, the haze is less than 30% in the wavelength range of visible light.
This makes it possible to maintain the high transparency of the transparent screen.

Further, the transparent screen is composed of a plurality of transparent screen substrates, and the unevenness of the main surface of the transparent screen substrate is in contact with another transparent screen substrate.
This makes it difficult for dirt to adhere.

Further, the image display system according to the present invention includes the transparent screen according to any one of claims 1 to 5, and a projector that projects image light onto the transparent screen. , It is configured to project image light on the uneven side of the transparent screen.
As a result, the high transparency of the transparent screen can be maintained, and the image projected from the projector can be clearly displayed on the transparent screen.

Further, the method for manufacturing a transparent screen according to the present invention is a method for manufacturing a transparent screen for displaying an image, in which at least one main surface of a glass substrate is subjected to wet sandblasting treatment to form irregularities on the main surface.
This makes it possible to obtain a transparent screen that maintains high transparency and maintains the resolution of the image displayed on the transparent screen.

Further, on the main surface, irregularities are formed in which the arithmetic roughness Ra is 1 nm or more and 500 nm or less, and the average length RSm of the roughness curve is 200 nm or more and 5000 nm or less.
As a result, the high transparency of the transparent screen can be maintained, and the image projected from the projector can be clearly displayed on the transparent screen.

According to the present invention, it is possible to obtain a transparent screen having a clear image and maintaining high transparency.

It is a schematic side sectional view which shows the transparent screen which concerns on 1st Embodiment of this invention. It is a schematic side sectional view which shows the transparent screen which concerns on 2nd Embodiment of this invention. It is a schematic side sectional view which shows the transparent screen which concerns on 3rd Embodiment of this invention. It is a schematic side sectional view for demonstrating a rear type transparent screen. It is a schematic side sectional view for demonstrating a rear type transparent screen.

Next, a mode for implementing the transparent screen and the image display system according to the present invention will be described with reference to the attached drawings.

The image display system 10 shown in FIG. 1 is an embodiment of an image display system provided with a transparent screen according to the present invention. The video display system 10 shown in FIG. 1 is a front-type video display system 10. The transparent screen scatters and reflects the light emitted from the image illuminating device installed on the same side as the observer side with respect to the transparent screen on the surface of the transparent screen substrate, and the scattered and reflected light is used as an image. , Is configured to display on the surface of a transparent screen.
The image display system 10 includes a transparent screen 20 for displaying an image and a projector 30 arranged diagonally above the transparent screen 20. The transparent screen 20 is a transparent screen according to the present invention, and the projector 30 is an example of a projector that projects an image on the transparent screen according to the present invention. In FIG. 1, the "observer side" is the side where the observer X exists, that is, the left side of the paper.

The image display system 10 displays an image on the transparent screen 20 by projecting the image light L from the projector 30 onto the transparent screen 20.
The transparent screen 20 can be used, for example, as a partition for partitioning a space.

The projector 30 is a projector capable of projecting the image light L on the transparent screen 20. The image light L is scattered by the transparent screen 20 to become reflected light R, and the image is displayed on the transparent screen 20. A part of the image light L is scattered and transmitted through the transparent screen 20. Therefore, the image can be confirmed from the side opposite to the observer X side. However, when the image is confirmed from the side opposite to the observer X side, the image appears to be inverted. Examples of the projector include a short focus projector. The short focus projector is a projector capable of projecting the image light L from a close distance of 10 to 90 cm.

(1) Transparent screen according to the first embodiment Next, the transparent screen 20 will be described. The transparent screen 20 is composed of, for example, a glass substrate, a quartz substrate, a transparent resin substrate such as polycarbonate, a crystallized glass substrate, a transparent ceramic substrate, and the like. In this embodiment, the transparent screen 20 is made of a glass substrate. Concavities and convexities are formed on at least one main surface 20a of the transparent screen 20. In FIG. 1, the unevenness is formed on the observer X side. As the glass substrate constituting the transparent screen 20, for example, a glass substrate made of aluminosilicate glass or borosilicate glass can be used. When the glass substrate is made of alkali-containing aluminosilicate glass, the glass substrate may have a chemically strengthened layer on the surface.
The thickness of the transparent screen 20 is preferably, for example, about 30 μm to 5 cm. When the transparent screen 20 is made of a glass substrate as in the present embodiment, if the thickness is 100 μm or less, the transparent screen 20 has flexibility, so that the shape of the transparent screen 20 can be freely designed.

The transparent screen 20 has translucency. The term "translucency" means that the light (sunlight, illumination, etc.) emitted from the opposite side of the transparent screen of the observer X is transmitted to the observer X side. For example, the average transmittance of visible light (wavelength range (380 nm to 780 nm)) of the transparent screen 20 is 40% or more. As a result, the light emitted from the opposite side of the transparent screen of the observer X can be transmitted to the observer X side. Specific examples of the glass substrate having such an average transmittance include soda lime glass, borosilicate glass, aluminoborosilicate glass, aluminosilicate glass, lithium aluminosilicate glass and the like.

The unevenness of the main surface 20a of the transparent screen 20 has an arithmetic mean roughness Ra of 1 nm or more and 500 nm or less.

Since the arithmetic mean roughness Ra on the main surface 20a of the transparent screen 20 is in such a range, the transparent screen 20 can display the image projected from the projector 30 while maintaining high transparency in the transparent screen 20. It can be clearly displayed on the top.

In the case of the present embodiment, the lower limit of the arithmetic mean roughness Ra on the transparent screen 20 is set to 1 nm, but it is preferably set to 10 nm, and more preferably set to 15 nm.
Further, although the upper limit of the arithmetic mean roughness Ra is set to 500 nm, it is preferably set to 400 nm, and more preferably set to 300 nm.

In the case of the present embodiment, since the average length RSm of the roughness curve on the transparent screen 20 is 200 nm or more and 5000 nm or less, the image projected from the projector 30 can be clearly displayed on the transparent screen 20. can.

In the case of the present embodiment, the lower limit of the average length RSm of the roughness curve in the transparent screen 20 is set to 200 nm, but it is preferably set to 250 nm, and more preferably 350 nm.
Further, although the upper limit of the average length RSm of the roughness curve is set to 5000 nm, it is preferably set to 4500 nm, and more preferably set to 4000 nm.

In the case of the present embodiment, in the transparent screen 20, since the maximum height roughness Rz is 30 nm or more and 600 nm or less, the image projected from the projector 30 is displayed on the transparent screen 20 while maintaining high transparency. Can be displayed clearly.

In the case of the present embodiment, the lower limit of the maximum height roughness Rz on the main surface 20a of the transparent screen 20 is set to 30 nm, but it is preferably set to 35 nm, more preferably 40 nm.
Further, although the upper limit of the maximum height roughness Rz is set to 600 nm, it is preferably set to 500 nm, and more preferably set to 400 nm.

The unevenness of the transparent screen 20 is such that the haze, which indicates the degree of cloudiness as an index related to transparency, is visible light from the viewpoint of the observer X sandwiching the transparent screen 20 and visually recognizing an object or a landscape on the opposite side where the observer X is located. It is formed so as to be less than 60% in the wavelength range (380 nm to 780 nm).
By setting the haze of the transparent screen 20 to less than 60%, high transparency can be maintained, and the observer X can visually recognize an object or a landscape on the opposite side of the transparent screen 20.

In the case of the present embodiment, the haze of the transparent screen 20 is set to less than 60%, but is preferably less than 50%, more preferably less than 30%, still more preferably less than 20%. ..

Further, it is possible to form an antifouling film for preventing dirt from adhering to at least one main surface of the transparent screen 20 and imparting water repellency and oil repellency.
The antifouling film preferably contains a fluorine-containing polymer containing silicon in the main chain. As the fluorine-containing polymer, for example, a polymer having a —Si—O—Si— unit in the main chain and having a water-repellent functional group containing fluorine in the side chain can be used. The fluorine-containing polymer can be synthesized, for example, by dehydrating and condensing silanol.

When the transparent screen 20 has an antifouling film, the unevenness of the surface of the antifouling film is within the range of the above-mentioned surface roughness (arithmetic surface roughness Ra, average length RSm of roughness curve, maximum height roughness Rz). As such, unevenness is formed on the main surface 20a of the transparent screen 20.
Further, when the transparent screen 20 has an antifouling film, unevenness is formed on the main surface 20a of the transparent screen 20 so that the haze of the transparent screen 20 after forming the antifouling film is within the above range.

Further, a film for imparting various functions may be attached to at least one main surface of the transparent screen 20. Examples of the film include a colored film, an antifouling film, an antireflection film, an antiglare film, and a breaking film.

Next, a method of manufacturing the transparent screen 20 having irregularities on the main surface 20a will be described.
The unevenness is formed by applying a wet blast treatment to the main surface 20a.
In the wet blast treatment, abrasive grains composed of solid particles such as alumina and a liquid such as water are uniformly agitated to form a slurry, which is then used from an injection nozzle to a work made of glass using compressed air. This is a process of forming irregularities on the work by injecting the work at a high speed.

In the wet blast treatment, when the slurry ejected at high speed collides with the work, the abrasive grains in the slurry scrape the surface of the work, so that unevenness is formed on the surface of the work. In this case, the abrasive grains sprayed on the work and the fragments of the work scraped by the abrasive grains are washed away by the liquid sprayed on the work, so that the number of particles remaining on the work is reduced. The transparent screen 20 is obtained by processing a work having irregularities on its surface into a desired size and shape by cutting or the like.

The surface roughness of the unevenness formed on the main surface of the work by the wet blast treatment can be adjusted mainly by the particle size distribution of the abrasive grains contained in the slurry and the injection pressure when the slurry is injected onto the work.

In the wet blasting process, when the slurry is sprayed onto the work, the liquid carries the abrasive grains to the work, so finer abrasive grains can be used compared to the dry blasting process, and when the abrasive grains collide with the work. The impact of the slurry is reduced, and it is possible to perform precise processing. When the dry blast treatment is used, it is difficult to form unevenness of an appropriate size even with small abrasive grains. By applying the wet blast treatment to the work in this way, it is easy to form unevenness of an appropriate size on the main surface 20a of the transparent screen 20, maintain high transparency, and display the image projected from the projector 30. , Can be clearly displayed on the transparent screen 20.

In the dry blast process, processing heat is generated in the work due to friction when the injected abrasive grains collide with the work, but in the wet blast process, the liquid constantly cools the surface of the work during the process. Therefore, the work is not heated by the blasting process. Further, it is possible to form irregularities on the main surface 20a of the transparent screen 20 by applying the dry blast treatment, but in the dry blast treatment, the impact when the abrasive grains collide with the main surface of the transparent screen 20 is large. Too much, the surface roughness of the main surface 20a on which the unevenness is formed tends to be large, and the transparency of the transparent screen 20 tends to be impaired.

Further, as a method of forming irregularities on the main surface 20a of the transparent screen 20, there is a method of etching the main surface 20a of the transparent screen 20 with hydrogen fluoride (HF) gas or hydrofluoric acid, and these etchings are used. The unevenness obtained tends to be small, and it tends to be difficult to clearly display the image.

(2) Transparent screen according to the second embodiment FIG. 2 is a schematic cross-sectional view showing the transparent screen 40 according to the second embodiment of the present invention. The transparent screen 40 has a structure in which two transparent screen substrates 41 having a main surface 41a having irregularities formed on one side thereof are superposed on each other. Specifically, it has a structure in which the main surfaces 41a of the transparent screen substrate 41 are overlapped with each other. Dirt easily adheres to the uneven surface of the transparent screen, and it is difficult to clean it. Since the transparent screen 40 according to the second embodiment does not have unevenness exposed, it is difficult for dirt to adhere to the transparent screen 40 and it is easy to clean.

The two transparent screen substrates 41 may be adhered to each other with an adhesive such as resin. Examples of the adhesive include a transparent adhesive made of a thermoplastic resin such as ethylene-vinyl acetate copolymer (EVA) and thermoplastic polyurethane (TPU).

(3) Transparent screen according to the third embodiment FIG. 3 is a schematic cross-sectional view showing the transparent screen 50 according to the third embodiment of the present invention. The transparent screen 50 has a structure in which a transparent screen substrate 51 having a main surface 51a on which irregularities are formed and a transparent screen substrate 52 having no irregularities are superposed on each other. Specifically, the structure is such that the main surface 51a of the transparent screen substrate 51 and the main surface 52a of the transparent screen substrate 52 are overlapped with each other. Since the main surface 51a on which the unevenness is formed is not exposed to the outside, it is difficult for dirt to adhere to it. The two transparent screen substrates 51 and 52 may be adhered with an adhesive such as resin.

In the above-described embodiment, the front-type video display system is used, but a rear-type transparent screen may be used, for example, as shown in FIGS. 4 and 5. In FIGS. 4 and 5, in the image display system 60, the image light L is projected from the projector 30 arranged in the direction opposite to the observer X side, and the image light L is scattered by the transparent screen, transmitted and scattered. It becomes light S, and an image is displayed on the transparent screen 20.

Next, an example of the transparent screen 20 having irregularities formed on the main surface 20a will be described. However, the transparent screen 20 is not limited to this.

[Preparation of sample]
In this example, samples 1 to 4 were prepared as examples of the transparent screen 20, and samples 5 and 6 were prepared as comparative examples.
As the transparent screen 20 used for the samples 1 to 6, an alkali-containing aluminosilicate glass substrate having a thickness of 1.1 mm was used.

The transparent screens 20 of the samples 1 to 4 as examples were produced by subjecting the above glass substrate having a thickness of 1.1 mm to a wet blast treatment to form irregularities on one of the main surfaces 20a.
Specifically, the glass substrate is placed on the glass substrate with a slurry prepared by uniformly stirring the abrasive grains composed of alumina having a particle size of # 4000 and water on the entire one main surface. Wet blasting was repeated twice using air having a predetermined processing pressure while moving the processing table at a speed of 10 mm / s. As the abrasive grains, abrasive grains having a polygonal shape were used.

In sample 1, the processing pressure when the slurry was sprayed onto the glass substrate was 0.1 MPa, and in sample 2, the processing pressure when the slurry was sprayed onto the glass substrate was 0.12 MPa, and sample 3 was used. The processing pressure when the slurry was sprayed onto the glass substrate was 0.15 MPa, and in the sample 4, the processing pressure when the slurry was sprayed onto the glass substrate was 0.25 MPa.

In the transparent screen 20 of the sample 5 as a comparative example, the main surface of the glass substrate is not treated. That is, the transparent screen 20 of the sample 5 is untreated.
The transparent screen of the sample 6 as a comparative example is applied to one main surface of the glass substrate by injecting a liquid containing the SiO ₂ component, and the applied liquid containing the SiO ₂ component is dried on the main surface. It was produced by forming a SiO ₂ coating film.

[Measurement of surface roughness]
The surface roughness of the main surface 20a on the transparent screen 20 of the samples 1 to 6 was measured. The surface roughness was measured on the main surface 20a subjected to the wet blast treatment for the samples 1 to 4, the main surface 20a on either side of the sample 5, and the SiO ₂ coating on the sample 6. This was done for the main surface 20a on the side where the film was formed.

The parameters of the measured surface roughness are the arithmetic surface roughness Ra, the maximum height roughness Rz, and the average length RSm of the roughness curve.
However, the arithmetic surface roughness Ra and the maximum height roughness Rz were measured for the samples 1 to 6, and the average length RSm of the roughness curve was measured for the samples 1 to 4, 6.

The arithmetic surface roughness Ra and the maximum height roughness Rz for the samples 1 to 5 were measured using an atomic force microscope (AFM).

The atomic force microscope used was an atomic force microscope (SPM unit: Division Icon, Controller unit: Nano Specpe V) manufactured by Bruker, and measurements were carried out based on JIS B0601-2013. Further, the measurement conditions were carried out using the tapping mode so that the scan rate was 1 Hz and the number of acquired data was 512 × 512 for the area of the measurement area 10 × 10 μm.

In the measurement of the arithmetic surface roughness Ra and the maximum height roughness Rz for the sample 6, since the measured value of the sample 6 is larger than the measured value of the samples 1 to 5, the measured value is larger than that of the atomic force microscope. This was done using a suitable laser microscope.
Further, the measurement of the average length RSm of the roughness curve for the samples 1 to 4 and 6 needs to measure a wider range than the other parameters measured in this example, and therefore has a wider range than the atomic force microscope. It was measured using a laser microscope suitable for measurement.

The laser microscope used was a Keyence laser microscope (VK-X250), and measurements were carried out based on JIS B0601-2013.
Further, the measurement was carried out so that the number of acquired data was 1024 × 768 pixels and the reference length was about 1/5 of the measurement area in the area of about 32 × 24 μm in the measurement area.

[Measurement result of surface roughness]
The measurement results of the surface roughness performed on the samples 1 to 6 will be described.
Table 1 shows the measurement results.

As shown in Table 1, the arithmetic surface roughness Ra is in the range of 6.9 nm to 18.4 nm for the samples 1 to 4 as examples, and the arithmetic surface roughness increases as the processing pressure of the wet blast treatment increases. The value of Ra also tends to increase. For sample 5, which is an untreated comparative example, Ra was smaller than that of samples 1 to 4, and was 0.2 nm. For sample 6, which is a comparative example in which the SiO ₂ coating film was formed, Ra was larger than that of samples 1 to 4, and the diameter was 146 nm.

The maximum height roughness Rz is in the range of 173 nm to 385 nm for the samples 1 to 4 as examples, and the value of the maximum height roughness Rz tends to increase as the treatment pressure of the wet blast treatment increases. .. Sample 5, which is an untreated comparative example, was smaller than Samples 1 to 4 and had a diameter of 14 nm. The sample 6 which was a comparative example in which the SiO ₂ coating film was formed was larger than the samples 1 to 4 and had a diameter of 831 nm.

The average length RSm of the roughness curve is in the range of 888 nm to 1220 nm for the samples 1 to 4 as examples, and the average length RSm of the roughness curve tends to increase as the treatment pressure of the wet blast treatment increases. It is in. The sample 6 which was a comparative example in which the SiO ₂ coating film was formed was larger than the samples 1 to 4 and had a diameter of 14404 nm.

[Measurement of haze]
Haze was measured for Samples 1, 4 and 6. The haze was measured based on JIS K7136 and JIS K7361-1 using a haze computer (Haze Computer HZ-2) manufactured by SUGA TESTINSTRUMENTS.

[Measurement result of haze]
As shown in Table 1, the haze is in the range of 0.22% to 1.77% for the samples 1 to 4 as examples, and the haze value increases as the treatment pressure of the wet blast treatment increases. There is a tendency. For sample 6 which is a comparative example in which the SiO ₂ coating film was formed, it was 10.9%, which was larger than that of samples 1 to 4.

[Video resolution evaluation]
The resolution of the image displayed on the transparent screen 20 by the projector 30 was evaluated. As an evaluation method, whether or not the image displayed on the transparent screen 20 can be clearly seen was evaluated in five stages shown below. 5: Clear image is visible 4: Image is sufficiently visible but less clear than 5 3: Image is visible 2: Image is visible but unclear, 1: Image is slightly visible and unclear.

[Resolution evaluation result]
As shown in Table 1, the resolution of the image was 3 or 4 for the samples 1 to 3 as examples, and 5 for the sample 4. The value was 1 for sample 5, which is an untreated comparative example. The number was 5 for sample 6, which is a comparative example in which the SiO ₂ coating film was formed.

[Visibility of the image on the opposite side of the transparent screen]
The visibility of the background on the opposite side where the observer X is located was evaluated with respect to the transparent screen 20. As an evaluation method, it was evaluated whether or not the observer X stood at a position 1 m away from the front of the transparent screen 20 and could see the background on the opposite side of the transparent screen 20. The case where the background on the opposite side of the transparent screen 20 was visible was marked with ◯, and the case where the background was not visible or was visible but was unclear was marked with x, and the visibility on the opposite side was determined.

[Results of visibility evaluation on the opposite side]
As shown in Table 1, the visibility on the opposite side was 0 for Samples 1 to 4 as Examples, and ○ for Sample 5 which was an untreated Comparative Example, and the Comparative Example in which the SiO ₂ coating film was formed was formed. For sample 6, the value was x.

[Comprehensive evaluation of each sample]
As shown in Table 1, for the samples 1 to 4 as examples, since the shape of the unevenness of the main surface 20a of the transparent screen 20 is appropriate, the image resolution is 3 or more and the visibility of the background on the opposite side is high. Good evaluation results such as ○ were obtained.
On the other hand, in the untreated sample 5, the resolution of the image was as low as 1 because the unevenness of the main surface 20a of the transparent screen 20 was small.
Further, in the sample 6 which is a comparative example in which the SiO ₂ coating film was formed, the unevenness was too large, so that the visibility of the background on the opposite side of the transparent screen 20 was x.

10 Video display system 20 Transparent screen 20a Main surface 30 Projector

Claims (7)

A transparent screen that displays images
Has unevenness on at least one main surface,
It is composed of a transparent screen substrate having an arithmetic average roughness Ra of 1 nm or more and 500 nm or less and an average length RSm of a roughness curve of 888 nm or more and 5000 nm or less on the main surface having irregularities. Characterized transparent screen. The transparent screen according to claim 1, wherein the maximum height roughness Rz on the main surface having irregularities is 30 nm or more and 600 nm or less. The transparent screen according to claim 1 or 2 , wherein the haze is less than 60% in the wavelength range of visible light. The transparent screen according to any one of claims 1 to 3 , wherein the haze is less than 30% in the wavelength range of visible light. The transparent screen is composed of a plurality of transparent screen substrates, and the unevenness of the main surface of the transparent screen substrate is in contact with another transparent screen substrate. The transparent screen according to any one of claims 4 . The transparent screen according to any one of claims 1 to 5 .
A projector that projects image light onto the transparent screen is provided.
The projector is a video display system characterized in that it is configured to project video light onto the unevenness of the transparent screen. A method of manufacturing a transparent screen that displays images.
Wet sandblasting is applied to at least one main surface of the glass substrate to create irregularities on the main surface where the arithmetic average roughness Ra is 1 nm or more and 500 nm or less, and the average length RSm of the roughness curve is 888 nm or more and 5000 nm or less. A method of manufacturing a transparent screen, characterized in that it is formed.

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