JPS598636A - Glass mirror for rearview mirror - Google Patents

Abstract

PURPOSE:To obtain the titled easily preparable resultant mirror having the preventing effects on the dazzling, by depositing the vapor of Al on a blue glass plate, containing SiO2, Al2O3, CaO, MgO, Na2O, K2O, Li2O and a colorant, and having given transmittance characteristics. CONSTITUTION:A blue glass plate, containing 60-75wt% SiO2, 0.5-5wt% Al2O3, 5-15wt% CaO, 0-10wt% MgO, 6-16wt% total of CaO and MgO, 10-18wt% Na2O, 0-10wt% K2O, 0-1wt% Li2O, 11-19wt% total of Na2O, K2O and Li2O, and 0.05-0.4wt% CuO, 0.002-0.1wt% Cr2O3 and 0.0005-0.005wt% CoO as a colorant, and having the following transmittance characteristics is used: The transmittance of the glass plate of 2mm. thickness is a maximum of 80+ or -10% at 500nm wavelength and 0.75+ or -0.15 ratio between the transmittances at 450nm and 550nm wavelengths. Al vapor is then deposited on one side of the blue glass plate to give the aimed glass mirror for a rearview mirror.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved glass mirror for a rearview mirror to prevent dazzling caused by reflected light.

Conventionally, rearview mirrors installed on vehicles such as automobiles are generally made of glass mirrors with chromium metal or aluminum vacuum-deposited on one side of the glass plate, but those with a reflective mirror surface coated with chromium metal have a reflective surface. rate is 40%
Because of the low level of reflection, it is often difficult to check the rear, especially at dusk.Those with aluminum-deposited reflective mirrors have a good reflectance of 8096, but
At night, the reflected light from the headlights of the vehicle behind the vehicle may cause a strong dazzle to the driver.

In order to prevent dazzle caused by strong reflected light from rearview mirrors, glass mirrors have been developed and put into practical use, which are made by coating transparent plate glass with almost no absorption with a multilayer coating of various metals. This glass mirror for rearview mirrors is designed so that the actual reflected light is 45 to 7096 meters centered around the wavelength of 50011 m, which has the highest visibility for humans, and further suppresses the reflected light from the headlights of the following vehicle as much as possible. wavelength 6
It is adjusted to block red light of 0.00 nm or more. However, in order to carry out metal multilayer coating treatment,
It requires a large capital investment in special vapor deposition equipment, as well as complex processes and advanced manufacturing techniques to perform several multilayer coatings.

The present invention has the same anti-glare effect as the above-mentioned glass mirror by vapor-depositing aluminum on a blue glass plate having predetermined transmittance characteristics instead of the above-mentioned glass mirror coated with a multilayer metal film. Moreover, it is an object of the present invention to provide a glass mirror for a rearview mirror that can be easily manufactured without requiring a special vapor deposition apparatus.

The present invention contains 5i0260-75% in weight percentage,
A/2030, 5-596. CaO5~1596.
M, gQ O ~ 10%, CaO + Mg0 6 ~ 169
6 + Na 2010~. 18%, K2O0~10
%, Lizo 0-196. 10+ for Na2O+
L12,011~19%1 CuOO,05 as colorant
~0.4%, CrzOa 0.002~0.196.
Contains Coo O, 0005 to 0.00596, and the transmittance of the glass is 2 mm thick at a wavelength of 500 nm.
It has a maximum value of 80±10% at wavelengths of 450 nm and 550 nm, and the ratio of transmittance at wavelengths of 450 nm and 550 nm is 1.0±0.1. wavelength 5
The ratio of transmittance between 00 nm and 600 nm is 0.75±0
This is a glass mirror for a rearview mirror made by vapor-depositing aluminum on one side of a blue glass plate No. 15.

In order to make it easy to check the rear view using the rearview mirror at dusk and to prevent the driver from being strongly dazzled by the light reflected from the headlights of the following vehicle, the substantial amount of light reflected from the reflective mirror surface must be at least 45%. 70%, but the present invention provides a rearview mirror with a wavelength of 5.
By using blue glass that has the highest transmittance at 0.001m, the actual reflected light is 45-70%,
In addition, it is possible to suppress light reflected from the headlights of vehicles following at night. Furthermore, it is undesirable for the reflected light color of a mirror surface to differ widely in color rendering during the daytime, so wavelengths of 4
Care is taken so that the transmittance curve at 50 to 55 Qnm approaches a flat line. In addition, blue is the color of reflected light from a mirror surface.
It has a physiological function that gives comfort to the human eye and reduces fatigue.

Next, the reason why the glass composition of the present invention is limited to the above range will be described.

5ins is used as the main component of glass, but if the content exceeds 7596, the softening temperature is high (too high, 6
If it is less than 0%, chemical durability deteriorates, which is not preferable.

Ae20m is used to prevent devitrification of glass and improve chemical durability, but if the content exceeds 596, striae will occur in the glass, and if it is less than 0.596, it will be difficult to maintain weather resistance. becomes.

When the CaO content exceeds 15%, devitrification occurs, and when it is less than 5%, weather resistance decreases. When MgO exceeds 1096, devitrification occurs. If the total content of 1CaO and MgO exceeds 1696, devitrification occurs, and if it is less than 6%, sufficient weather resistance cannot be obtained.

If the content of Na2O exceeds 8% per month, the expansion coefficient becomes too large and the side weatherability deteriorates, and if it is less than 10946, the meltability deteriorates and the expansion QI4 coefficient also decreases. LizO exceeding 1096 and exceeding 20.196 are both expensive in raw material cost compared to NazO and cannot be practically employed.

, Naz O* K2O*, and the total amount of Lis+O contained in 19. If it exceeds 1196%, the expansion coefficient becomes excessive and weather resistance deteriorates, and if it is less than 1196, the meltability deteriorates and the expansion coefficient decreases.

As the coloring agent, CuO, which absorbs in the near infrared region during oxidative melting, is used. Cu io/ exhibits a clear blue color in soda lime glass and has a wavelength of 800 to 9001 m.
It has an absorption peak at Cr2α exists mainly as 6+ Cr ions in soda lime glass during oxidative melting, and has a wavelength of 4501 m and a wavelength of 650 T.
It has a maximum absorption peak at 1 m, and has the function of maintaining the flatness of the transmittance curve in the wavelength range of 450 to 5501 m due to the balance with the absorption effect of CLIO. Co
O becomes Co io/ and coordinates four oxygen ions to become C
OO4 group is formed and colored blue.

Cu less than 00.05%, Cr20a less than 0.002%, Co.

If it is less than 0.0005%, each absorption capacity is insufficient and the desired absorption characteristics cannot be exhibited. Also CuOO, 4%C
If either r20n O, 196 or Coo O, 00596 exceeds, absorption at a wavelength of 500 nm increases and exceeds the permissible limit of the predetermined transmittance characteristics, which is not appropriate. The content of coloring components other than the above is Fe2
Om is 0.1% or less, M n 02 is 0.05% or less, and both are limited to the glass number and the amount introduced as impurities.

The glass of the present invention has a transmittance of 80±1 at a wavelength of 500 nm at a wall thickness of 2 mm due to the combination of colorants as described above.
096, the ratio of transmittance between wavelengths of 450 nm and 550 nm is 1.0±0.1, and wavelengths of 500 nm and 600 nm.
The color is adjusted so that the ratio of transmittance to

The subcomponents include B20a*Bad, SOs,
As2O5°Sbz Oa, C1, F, etc. may be added in an amount of 196 or less to promote melting and clarification.

Examples of blue glass according to the present invention are shown in the following table.

Oxide compositions are given in weight percentages. These glasses are made by mixing stone powder, aluminum hydroxide, calcium carbonate, dolomite, potassium carbonate, soda ash, and colorants such as cupric oxide, potassium dichromate, cobalt oxide, etc. according to the target composition, and then heating them in a crucible or tank furnace. melted at the wall thickness 2
．． A zero plate polishing plate was prepared and its transmittance characteristics were measured.

Regarding the sample of glass Nα3 shown in the above table, its spectral transmittance curve (1) and the spectral reflectance curve (2
) is shown in the drawing. The actual reflected light has a reflectance of 8096 on the aluminum evaporated surface and is absorbed again by the front glass, so it is determined by (transmittance of glass) 2xo,s, and the central maximum value of absorption at a wavelength of 500 nm. is 58%
Therefore, when applied to a rearview mirror, a great effect can be obtained in preventing glare from reflected light.

As detailed above, the glass mirror for rearview mirror of the present invention is made by vapor-depositing aluminum on one surface of a blue glass plate having predetermined transmittance characteristics, and has good color rendering properties of reflected light color in the daytime, and in the evening. This makes it easy to check the rear view at night, and also has an excellent anti-glare effect against reflected light from the headlights of following vehicles at night.

[Brief explanation of the drawing]

The drawing is a curve diagram showing the spectral transmittance characteristics of the glass and the spectral reflectance characteristics of reflected light according to the present invention. In the figure, (1) is a spectral transmittance curve, and (2) is a spectral reflectance curve. Patent applicant: Toshiba Glass Corporation Wavelength (nm)

Claims (1)

[Claims] Weight percentage: 810260-75%, Affi20.
0.5-5%. Ca03~15961Mg0O~10%, CaO+Mg
06-16% Na2010-1896. K2O0~1
0%, LhOO~196°Na 20+ to 20+Li
2011~19%, Cu0O,05~ as colorant
0,496. Cr2on 0.002-0.1%,
Contains Co0O, 0O05 to 0.00596, and the transmittance of the glass is 500n in wavelength in a glass with a wall thickness of 9mm.
It has a maximum value of 80±1096 in m, and the ratio of transmittance between wavelengths of 450 nm and 550 nm is 1.0±061. wavelength 50
The ratio of transmittance between 0 nm and 600 nm is 0.75±0
．． A glass mirror for a rearview mirror made by vapor-depositing aluminum on one side of a blue glass plate.