KR100547192B1 - Anti-glare mirror by photochromic polymer matrix coating - Google Patents

Abstract

The present invention relates to a photochromic mirror made by coating a photochromic polymer matrix on a glass to a predetermined thickness so that transmittance or reflectance can be adjusted. More specifically, the front and bottom surfaces of the glass or transparent synthetic resin plate on each side of the upper and lower surfaces thereof are polished. The mirror is made through the deposition process on the inside, and the back side is coated with a polymer material including a photochromic organic compound, and an ultraviolet lamp is disposed on each side of the upper and lower surfaces of the polished glass to activate the photochromic coating layer and irradiated into the glass. The present invention relates to a vehicle anti-glare mirror that can change the reflectance of the photochromic mirror to protect the driver's vision from the strong light or sunlight of the vehicle.

In addition, when the optical sensor detects the intensity of light applied from the outside and sends a signal, the voltage control circuit recognizes the signal and supplies the required voltage to the lamp to adjust the amount of ultraviolet radiation to change the reflectance of the mirror. It was made possible.

Description

Anti-glare mirror by photochromic polymer matrix coating {ANTI-DAZZLING MIRROR UTILIZING PHOTOCHROMIC HIGH POLYMER MATRIX COATING}

1A and 1B are cross-sectional views showing the internal structure and visible light reflection of the Miller according to the present invention.

2A and 2B are cross-sectional views illustrating the principle of total internal reflection of a medium according to the present invention;

Figure 3 is a graph showing the reflectance for each wavelength band of the photochromic material coating layer in accordance with Example 1 of the present invention.

Figure 4 is a graph showing the reflectance for each wavelength band of the photochromic material coating layer according to the second embodiment of the present invention.

The present invention relates to a car anti-glare mirror that can protect the driver's field of view caused by strong light or sunlight of the car by coating the photochromic polymer matrix to a predetermined thickness of the glass to enable adjustment of the transmittance or reflectance. .

Conventionally, various methods have been studied in order to prevent glare due to light from the rear in a vehicle rearview mirror or a side mirror, among which various technologies have been used to apply a liquid crystal compound (see US Patent No. 6,175,479, 6,175,441, 6,193,912, 6,193,378, etc.).

Mirrors using such liquid crystal compounds have a fast and stable effect, but require high precision in manufacturing, have a high manufacturing price, and a small number of companies have monopolized the technology.

As a solution for this, a method of coating a photochromic organic compound on glass or a mirror (US Pat. No. 5,373,392, UK Patent No. 2115573, and European Patent No. 0568210 and its corresponding Japanese Patent No. Hei 6-51352) has been proposed.

The photochromic organic compound is a substance having a characteristic of changing to a specific color by ultraviolet rays contained in light, and being reduced to an initial color again when blocking light. An ultraviolet lamp is used to impart discoloration characteristics at night, Ultraviolet transmission mirrors with an insulating thin film coating on glass have been proposed.

Ultraviolet ray transmissive mirror is a mirror that transmits ultraviolet wavelength band and reflects visible wavelength band by reflecting light by repeatedly depositing material having high refractive index and low refractive index in multilayer structure by using insulating thin film coating which is generally used for optical applications. It is a technology that simultaneously gives the role and discoloration characteristics by ultraviolet light transmission.

However, when using the insulating thin film coating mirror manufactured by the above vapor deposition method, it is difficult to completely block visible light generated from the lamp, and economically, the process of forming the insulating thin film coating layer is complicated and difficult, resulting in many defect rates. There is a disadvantage in that productivity is reduced.

Accordingly, the present invention was devised to solve the above problems, and the present invention deviates from the technology using a liquid crystal compound that is monopolized and at the same time does not use an insulating coating mirror, and polishes glass or transparent plastic in the medium. Anti-glare mirror with excellent productivity, quality and price competitiveness by constructing a simple photochromic mirror that is easy to manufacture and reduces manufacturing cost through the study of a new method of discoloring photochromic materials by utilizing the total internal reflection characteristics of light. The purpose is to provide.

According to the present invention for achieving the above object, when the angle of incidence of the UV lamp is properly adjusted to enter the medium having a similar refractive index at an angle greater than the critical angle, the light is not emitted to the outside and total reflection occurs only inside the medium layer. In other words, when a photochromic polymer matrix containing a photochromic organic compound is coated on a medium having a similar refractive index such as glass or transparent plastic, and then the lamp is irradiated from the upper and lower sides of the medium, the light and the coating layer are the same. Recognition as a material causes total internal reflection to cause discoloration of the uniform photochromic coating layer.

In this case, it is important to arrange the lamp so that the incident angle of light with respect to the medium to be used is greater than or equal to the critical angle in order for ultraviolet light emitted from the lamp to form total internal reflection. The critical angle can be easily determined by knowing the refractive index of the medium to be used and substituting it into Snell's Law.

Important characteristics in the present invention include the uniformity, the response speed and the change in reflectance when discoloring through total reflection of the inside of the coating layer of ultraviolet rays, in addition, the life and durability of the ultraviolet lamp is also important.

BEST MODE Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is to provide a photochromic mirror for automobiles by coating a photochromic polymer matrix containing a photochromic organic compound in a predetermined thickness on a glass or transparent synthetic resin sheet.

In the present invention, the reflectance or transmittance of the mirror changes depending on the characteristics of the photochromic organic compound.

A photochromic organic compound is a substance having a characteristic of reversible color change that is changed to a specific color when the molecular structure is activated when exposed to sunlight or ultraviolet rays, and when light is blocked.

Representative photochromic organic compounds generally known include spiropyrane-based materials, spiroxazine-based materials, vylologen-based materials, and diarylethene-based materials.

Photochromic organic compounds such as spiropyran and spirooxazine are in the form of a solid powder and do not have photochromic properties in the solid state. In most cases, photochromic organic compounds are mixed with a polymer host and coated to manufacture a product. The characteristics such as discoloration and reduction rate, transmittance or reflectance, and durability are determined by the affinity of the photochromic organic compound and the polymer matrix.

Polymeric hosts for photochromic organic compounds include cellulose resins such as ethyl cellulose, acrylic resins such as polymethyl methacrylate, silicone resins, epoxy resins, polycarbonates, polystyrenes, polyvinyl alcohols, polyvinyl chlorides, and polyurethanes. Copolymerized polymers and the like are known.

1 is a view illustrating an internal structure of a photochromic mirror for a vehicle according to the present invention, and FIG. 1A illustrates a case in which the ultraviolet lamp 6 is in an OFF state, and FIG. 1B is in an ON state.

In the general configuration of the mirror configuration of the present invention, a medium 4, which is a glass plate or a transparent synthetic resin plate, is installed inside the housing 10 in which the optical sensor 9 is installed at one side, and the upper and lower side surfaces of the medium 4 are In the polished state, one or more ultraviolet lamps 6 and a reflecting plate 7 for maximizing their efficiency are selectively positioned, and silver or chromium is deposited on the inner surface of the medium to make a mirror reflecting light. A deposition material layer 5 is formed, and the outer surface is coated with a polymer coating layer 3 containing a photochromic organic compound, a UV blocking coating layer 2, and a protective glass 1 in order, and inside the housing 10. The PCB board 8 is provided.

The housing 10 is preferably made of a plastic material suitable for automotive use. In general, rectangular shaped products are used, but are not limited thereto.

In the state of FIG. 1A, it can be seen that almost all visible light flowing from the outside of the housing 10, that is, the air, is reflected by the deposition material layer 5 having the mirror, where the ultraviolet lamp 6 is in the OFF state. Of course, the ultraviolet ray contained in the external light is not introduced into the housing 10 by the UV blocking coating layer 2, so that the photochromic polymer coating layer 3 does not discolor.

On the other hand, FIG. 1B shows that the visible light flowing from the outside is absorbed by the photochromic coating layer 3 in a considerable amount, thereby reducing the amount of reflection. The UV lamp 6 emits light to discolor the photochromic coating layer 3 to prevent glare. It is.

For example, in the state of FIG. 1B, when the light sensor 9 recognizes that it is at night, when a lot of light flows into the light sensor 9 by the headlight of the vehicle following from behind, the PCB substrate 8 The ultraviolet lamp 6 emits light by the generated electrical signal.

At this time, the ultraviolet rays irradiated from the lamp 6 are transferred to the photochromic polymer coating layer 3 through total internal reflection of the medium 4 to induce uniform discoloration, which is an important point of the present invention. The lamp 6 may be installed at the same time on the upper and lower ends of the medium 4, or may be selectively installed at the upper or lower end as shown.

That is, when light is irradiated at an angle of incidence greater than the critical angle, all of the light is reflected according to Snell's Law, which is a general law of reflection. In the present invention, the light is prevented from being refracted to the outside. Ultraviolet rays irradiated from the lamp 6 are totally reflected inside the medium 4.

FIG. 2 is a diagram showing total internal reflection of light, and FIG. 2A shows that when light is incident from a dense medium to an insignificant medium, gradually increasing the incident angle θ _i results in total reflection at a specific angle. .

That is, when light is incident from a material having a large refractive index to a small material, when the incident angle is greater than or equal to the critical angle θ _imax , the phenomenon in which all of the light is reflected and transmitted through the interface is called internal reflection.

The critical angle θ _imax is an incident angle when the refractive angle θ _r is 90 °. The critical angle θ _imax can be determined by knowing the refractive index of each medium and using the Snell's Law indicated below.

_{n 0 sinθ imax = n 1 sin90} ° sinθ imax = (n 1 / n 0)

Where n ₀ (refractive index of glass) = 1.5, n ₁ (refractive index of air) = 1

sinθ _imax = (1 / 1.5) = 0.667 θ _imax = 41.8 °

When using glass, the critical angle was found to be about 42 °.

As shown in Fig. 2b, when the incident angle θ _i is larger than the critical angle θ _imax , that is, when the incident angle is irradiated with the angle of incidence 42 ° or more, all the light is reflected and transmitted through the interface between glass and air. Since total reflection occurs, in the present invention, the irradiation angle of the lamp 6 is set to be 42 ° or more with respect to the medium 4.

On the other hand, the polymer coating layer 3 containing the photochromic organic compound was coated on the outer surface of the medium (4), the UV blocking coating layer (2) made of a transparent polymer with an ultraviolet absorber added to the outside of the photochromic coating layer (3) In order to completely block external leakage of ultraviolet rays transmitted through the photochromic coating layer 3 without being partially absorbed by the photochromic coating layer 3, the photochromic coating layer was prevented from being contaminated and damaged.

The ultraviolet lamp 6 for activating the photochromic material is disposed on the upper and lower sides of the medium 4 coated with the photochromic support layer. In the present invention, the diameter of the lamp is very small and the ultraviolet cathode tube is excellent in vibration resistance. Fluorescent lamp (UV CCFL; UV Cold Cathode Fluoroscence Lamp) was used.

However, the diameter and the number of installation of the ultraviolet lamp 6 and the selective installation of the upper and lower ends of the ultraviolet lamp 6 according to the present invention may vary depending on conditions such as the area of the photochromic coating layer 3 to be discolored and the uniformity of discoloration. .

On the other hand, in order to increase the transmission efficiency of the ultraviolet ray of the ultraviolet ray lamp 6 into the medium, a reflector plate 7 in which aluminum is deposited is installed on the rear surface of the lamp, and the ultraviolet ray lamp 6 is turned on at the rear of the deposition material layer 5. The PCB board | substrate 8 of the voltage control circuit to turn off was arrange | positioned.

The PCB substrate 8 for the voltage control circuit recognizes and calculates a signal transmitted by the optical sensor 9 installed in a predetermined portion of the housing 10 and senses the external light quantity, and converts the voltage of the appropriate magnitude into an ultraviolet lamp. (6) to serve or cut off.

Hereinafter, the present invention will be described in detail with reference to Examples, which illustrate the present invention and do not limit the scope of the present invention.

Example 1

The photochromic organic compound coating solution was dissolved in 1 g of 1,3,3-trimethylindolinonaphthospiroxo photograph in 20 g of tetrahydrofuran, and 10 g of polymethylmethacrylate and 0.1 g of Cyasorb UV-5411 The product was prepared by addition.

The prepared coating solution was coated with a spin coater (5 cm × 20 cm) on a silver-coated polished mirror with a thickness of 15 μm and dried in an oven at 60 ° C. for 1 hour to prepare a photochromic mirror. Two cold cathode tube fluorescent lamps were attached to the polished upper and lower surfaces of the prepared photochromic mirror together with the reflection shades to measure reflectivity before and after discoloration of the photochromic coating.

The reflectivity of the photochromic mirror was measured using a spectrophotometer (Minolta CM-3600D).

As a result of measuring the average reflectance change in the visible wavelength range before and after discoloration, the reflectance, which was 89.6% before discoloration, decreased to 25.35% after 20 seconds of irradiation with ultraviolet rays, and the color recovery time required to recover the reflectance to 50%. The measurement time was 8 seconds.

Example 2

The photochromic organic compound coating solution was prepared by dissolving a photochromic material of blue and purple types in 20 g of tetrahydrofuran, and adding 5 g of ethyl cellulose and 0.1 g of Cyasorb UV-5411.

After the coating layer was formed under the same conditions as in Example 1 using the prepared coating solution, the spectrophotometer (Minolta CM-3600D) was used to measure reflectance before and after discoloration.

As a result of measuring the average reflectance change in the visible wavelength range before and after discoloration, the reflectance, which was 88.7% before discoloration, was reduced to 9.45% after 20 seconds of irradiation with ultraviolet rays, and the color recovery time was required to recover the reflectance to 50%. The measurement time was 15 seconds.

According to the present invention for preventing glare as described above, the inside of the medium only by glass or transparent synthetic resin, without forming an insulating film coating layer of a complicated process by repeatedly depositing a material having a high refractive index and a low refractive index in a multilayer structure Since photochromic can be achieved through total reflection, the structure is simple and easy to manufacture, which significantly reduces the defective rate, and the manufacturing cost is low, and the photochromic effect is high, and the glare caused by light can be effectively prevented. This is a very advanced invention that can improve quality and price competitiveness.

In addition, according to the present invention, the anti-glare mirror according to the present invention does not need to use expensive liquid crystal compounds exclusively performed by a few foreign companies, but does not pay expensive royalties by providing an anti-glare mirror having a corresponding function. It is possible to contribute to the base of the anti-glare mirror.

Claims (5)

In the configuration for preventing glare by using a photochromic material in the housing 10 in which a vehicle side mirror or a room mirror is formed, A deposition material layer 5 for reflecting light is formed on the rear surface of the medium 4, which is a glass plate or a transparent synthetic resin plate having a predetermined shape, and the polymer coating layer 3 and the UV blocking coating layer containing a photochromic organic compound on the front surface thereof. (2) is formed in this order, Anti-glare mirror by the photochromic polymer matrix coating, characterized in that one or more of the plurality of ultraviolet lamps (6) is selectively installed on the top and / or bottom of the medium. The method according to claim 1, The anti-glare mirror by the photochromic polymer matrix coating, characterized in that the ultraviolet lamp 6 is irradiated with the ultraviolet light incident on the medium 4 is larger than the critical angle. The method according to claim 1 or 2, The shade plate 7 of the shade shape for the reflection efficiency of ultraviolet rays is installed around the ultraviolet lamp 6, The anti-glare mirror by the photochromic polymer matrix coating, characterized in that when the ultraviolet light by the reflector is irradiated into the medium, it is irradiated larger than the critical angle. The method according to claim 1 or 2, The optical sensor 9 is installed at a predetermined position of the housing 10, An anti-glare mirror by a photochromic polymer matrix coating, characterized in that the PCB substrate (8) for controlling the lighting of the ultraviolet lamp (6) is installed in the housing in accordance with the amount of light detected from the optical sensor. The method according to claim 1 or 2, The anti-glare mirror by the photochromic polymer matrix coating, characterized in that the front surface of the housing (10) further comprises a protective glass (1) for protecting the sunscreen coating layer (2).

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