The present invention relates to multilayer glass.
Light-emitting parts equipped with light-emitting diodes (LEDs) are provided by installing LEDs in a gap formed between two glass sheets, and by sealing the gap with a sealing material. Patent Literature 1 mentioned below describes a light emission structure in which electrodes are formed on the surfaces of two glass sheets and the electrodes are connected to LEDs.
Patent Literature 1: Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2009-512977
In Patent Literature 1 mentioned above, LEDs are sealed within a gap with a lead glass frit. Sealing the gap with a glass frit involves melting the glass frit and joining the glass sheets together. A processing temperature for the lead glass frit is generally high, and therefore, there is a possibility that the LEDs are damaged by processing heat during a sealing process.
The present invention has been made in view of a problem noted above and is intended to decrease the processing temperature for a multilayer glass in which optical elements are packed and reduce the possibility of damaging the optical elements during processing.
A multilayer glass pertaining to the present invention is such that a gap formed between glass plates is sealed with a sealing material that can be fixed at a process temperature that is lower than the processing temperature for optical elements.
According to a multilayer glass pertaining to the present invention, it is possible to decrease the process temperature for a multilayer glass including optical elements.
Problems, configurations, and advantageous effects which are other than noted above will become apparent from the following description of embodiments.
The glass plates 10 and 11 are of planar glass and, for example, those having high transmittance for visible light can be used as them. The surface of the inner side (abutting the gap 5) of each glass plate is preferably flat from a perspective of convenience for placing conductors 30 thereon, but the inner side may, for example, have a gently curved surface. The glass plates 10 and 11 are not necessarily required to be equal in size. Although the type of the glass plates 10 and 11 is not defined specifically, soda-lime glass, white sheet glass, air-cooled hardened glass, etc. may expediently be used.
The conductors 30 are each formed in two wires connected to an anode and a cathode of an LED 2. Separate conductors 30 may be provided for each LED 2 or a plurality of LEDs 2 may be connected in series with a single conductor 30, as depicted in
On a part of the surface of the glass plate 11 that does not overlap with the glass plate 10, the conductors 30 are formed so as to be pulled out. By connecting these pulled out conductors with an external circuit (not depicted), power can be supplied to the LEDs 2. By making this part having the pulled out conductors non-overlapping with the glass plate 10, connection with an external circuit and assembly are facilitated. In the case of sandwiching the conductors 30 between the glass plates, as depicted in
The LEDs 2 are turned on by applying a voltage to the LEDs 2 from an external circuit (not depicted) via the conductors 30. Light of the LEDs 2 mainly irradiates the outside periphery of the multilayer glass through the glass plates 10 and 11.
As the conductors 30, metal wires having a low electrical resistance can be used. The conductors 30 are formed in advance on the glass plate. As the conductors 30, it is preferable to use a transparent electrode of indium tin oxide (ITO: tin-doped indium oxide), indium zinc oxide (IZO), and a carbon nanotube among others, because the conductors 30 become less apparent. Even metal wires can be made nearly transparent by thinning its film thickness. Also, a Flexible Printed Circuit (FPC) with the conductors 30 mounted thereon may be sandwiched for use between the glass plates. In this case, it is also possible to mount optical elements on the FPC beforehand.
As the low-temperature sealing material 4, it is preferable to use a sealing material whose melting point is as low as possible and its softening point is preferably not more than 350° C., and more preferably, not more than 300° C. The softening point termed here refers to a second endothermic peak temperature by differential thermal analysis (DTA). For example, vanadic glass (glass containing vanadium as a constituent element) such as AG2O—V2O5—TeO2 has a softening point ranging from, approximately, 220° C. to 280° C. and it is preferable as the low-temperature sealing material 4, because it can seal the gap 5 at the above-mentioned temperature. It is also preferable as the sealing material for hardened glass in which compression stress is relieved and its hardening performance decreases when its temperature is increased up to 400° C. or above. In addition, particularly to suppress crystallization of glass, it is possible to add a substance mentioned below in a very low dose to vanadic glass: BaO, WO3, Y2O3, La2O3, Al2O3, Fe2O3, etc. To reduce the generation of stress at seal portions, a low thermal expansion filler (ZWP filter) may be dosed to match thermal expansion of the glass plates and thermal expansion of the seal portions. Alternatively, a metal filler (such as Sn or Al) may be dosed to relieve stress.
In a process of sealing the gap 5 with the low-temperature sealing material 4, a way that heats the entire multilayer glass 1 at a temperature from 220° C. to 280° C. or a way that locally heats only in the vicinity of the seal portions may be used. In the latter case, the glass may be prevented from being broken by preheating the entire glass to decrease the temperature difference between locally heated portions and other portions. Since the melting point of the low-temperature sealing material 4 is low, even in a case where the sealing process is performed after optical elements 2 are installed within the gap 5, damage to these members can be reduced. Moreover, even in a case where the conductors 30 are disposed in the vicinity of the seal portions as depicted in
Vanadic glass has low gas permeability, while having a property of adsorbing gas. Hence, when the gap 5 is put in a vacuum state (or near vacuum state), it is possible to adsorb internal gas, while preventing entering of air from outside, and therefore, the degree of vacuum after sealing can be increased or maintained.
The gap 5 is a space that is sandwiched between the glass plates 10 and 11 and formed inside the multilayer glass. The distance between the glass plates 10 and 11 (height of the gap 5) ranges, for example, approximately, from 0.2 mm to 10 mm. By providing the gap 5, the heat insulation property of the multilayer glass 1 can be improved. It is preferable that the gap 5 is internally vacuum, e.g., at approximately 10̂-3 Pa, from a perspective of adiabaticity. As necessary, inter alia, argon gas, air, or a desiccant may be packed in the gap 5. In either a case where the gap 5 is made internally vacuum or a case where gas is packed, the gap 5 has a refraction index of 1, whereas optical members such as lenses which are mounted on the optical elements 2 (e.g., LEDs or cameras) are made of glass or resin having a refraction index of 1.4 to 1.6. Hence, the difference between these refraction indexes enables the optical members to function as lenses.
Since the multilayer glass 1 pertaining to this first embodiment uses the low-temperature sealing material 4 (e.g., vanadic glass) in the seal portions, it is possible to decrease processing temperature when joining the glass plates 10 and 11 together and reduce thermal damage to the LEDs 2 and the conductors 30. In addition, since vanadic glass adsorbs gas, in a case where the gap 5 is made internally vacuum, it is possible to adsorb gas, even if emitted by the LEDs 2 or the like, and maintain the degree of vacuum. By maintaining the degree of vacuum within the gap 5, it is possible to maintain the heat insulation property of the multilayer glass 1.
In this first embodiment, since the low-temperature sealing material 4 serves as isolation between the gap 5 and outside, it is possible to prevent that the optical elements 2 are exposed to halogen gas or sulfidizing gas and corrodes or deteriorates. In addition, the low-temperature sealing material 4 provides an advantageous effect of preventing some of light emitted by the LEDs from leaking out of the gap 5 unnecessarily.
A processing temperature (a softening point for a glass sealing material) when fixing the low-temperature sealing material 4 has an effect on a temperature that is applied to the optical elements mounted on the glass plate and is, preferably, lower than a processing temperature when manufacturing the optical elements 2 or a temperature when mounting the optical elements on the glass. This is because, if the gap 5 is sealed at a higher temperature than the processing temperature for the optical elements 2, the processing heat for the sealing increases the probability of thermal damage to the optical elements 2. The processing temperature for the optical elements 2, termed here, is, for example, a temperature when depositing semiconductor layers. If heat that is higher than this temperature is applied, there is a possibility that the optical elements are subjected to unintended processing; therefore, a sealing temperature was set to be lower than this temperature. If a temperature when processing the optical elements 2 differs for different processes, the lowest temperature should be selected as a reference and it is preferable to set the sealing temperature lower than the lowest temperature. In addition, in a case where the optical elements 2 include a member made of resin or the like, it is preferable that a temperature of the optical elements 2, when fixing the low-temperature sealing material 4, is set to be lower than either the processing temperature for the resin or the temperature when mounting the optical elements 2, whichever is higher.
The spacer 6 can be made of a material such as, e.g., glass, ceramics, and resin. The shape of the spacer 6 can be selected appropriately. For instance, if a spherical glass bead is used as the spacer 6, a suitable number of spacers 6 are distributed within the gap 5 before sealing the gap 5, and then the gap 5 is sealed. Alternatively, columnar spacers 6 may be arranged on the glass plate and fixed by applying heat.
If it is desired to avoid that the glass plate 10 and the LEDs 2 contact with each other, the height of each spacer 6 should be made higher than the height of the LEDs 2 and each spacer 6 should be placed relatively near each LED 2. If it is sufficient to avoid that glass plates 10 and 11 contact with each other, the height of each spacer 6 may not necessarily be higher than the height of the LEDs.
Placing spacers 6 within the gap 5 can prevent the glass plates 10 and 11 from bending and contacting with each other, especially when the gap 5 has internally been put in a vacuum state. In other words, it is possible to prevent degradation in the heat insulation property of the multilayer glass 1.
According to the structure depicted in
In the third embodiment, since both the top and bottom edges of each LED 2 contact with a conductor, heat that is generated when the LEDs 2 emit light can be dissipated through both the glass plates 10 and 11. This provides an advantageous effect of decreasing the temperature of the LEDs 2 and increasing light emission efficiency. In addition, if the multilayer glass 1 is used outdoors, as heat is conducted to the glass plates, it is possible to lessen snow and ice accretion on the surfaces of the glass plates. To further reduce snow and ice accretion, a nichrome wire or the like may be placed inside the glass plates to heat them appropriately. [0033]
By adjusting the film thickness of the conductors 30, it is possible to reflect light in a particular wavelength region, taking advantage of an interference effect. For instance, sunburn can be prevented by reflecting ultraviolet light. Alternatively, temperature rise because of unnecessary sun radiation can be suppressed by reflecting infrared light. A wavelength region to be reflected and a wavelength region to be transmitted may overlap partially or may be made not to overlap completely.
Members to transmit light or reflect light can be provided separately from the conductors 30. For instance, the conductors 30 are configured as is the case for the first through third embodiments and members to reflect light with a particular wavelength may be placed in portions where the conductors 30 are not formed. Alternatively, a subset of the conductors 30 may be used only to reflect light, without being connected to the LEDs 2.
It is preferable to propagate an imaging signal to be transmitted and received by the camera 7 using a wire that has less signal degradation. For example, by fixing the FPC with a conductor 30 mounted thereon onto the surface of a glass plate and connecting it with the camera 7, it is possible to form the conductor 30 that is of a better quality than when the conductor 30 is directly formed on the surface of the glass plate.
The surface of the glass plate 11 may be provided with concave portions or convex portions and the camera 7 may capture an image across these portions; thereby, the glass plate 11 itself can be allowed to function as a lens. Likewise, the surface of the glass plate 10 or 11 may be provided with concave portions or convex portions and can be allowed to function as a lens to converge and spread light. Moreover, these concave portions or convex portions can be used as members for fitting and positioning the LEDs 21, 22, and camera 7.
In this fifth embodiment 5, one manner of utilization conceivable is that a computer becomes aware of a viewer 9 coming close to the multilayer glass 1 based on an image captured by the camera 7 and the LEDs 21 and 22 illuminate the object 8 according to instructions of the computer. In addition, it is also possible to display characters and graphics suitable for, inter alia, the age of the viewer 9 using the LEDs arranged in an array described with
When a user looks in the inside of the refrigerator, the light modulation film 100 turns to the light transmitting state and the inside of the refrigerator is illuminated by the LEDs 2 as necessary. This enables it to view the inside of the refrigerator without opening and closing the front door, and therefore, it is possible to save energy consumption to maintain the temperature inside the refrigerator.
A coefficient of overall heat transmission which indicates the heat insulation performance of the multilayer glasses 1a to 1c is preferably smaller than 1 W/m2·K, and more preferably, smaller than 0.5 W/m2·K. To improve the heat insulation performance, a multilayer glass having two or more layers of gap 5 may be used.
The present invention is not limited to the described embodiments and various modifications are included therein. The foregoing embodiments are those described in detail to explain the present invention clearly and the present invention is not necessarily limited to those including all components described. In addition, a subset of the components of an embodiment can be replaced by components of another embodiment. Also, components of an embodiment can be added to the components of another embodiment. Also, for a subset of the components of each embodiment, other components can be added to the subset or the subset can be removed or replaced by other components.
In the foregoing embodiments, as the LEDs 2, just the LED elements can be used, in addition to packaged ones. Also in the foregoing embodiments, although examples are described in which optical elements are placed between the glass plates 10 and 11, it is also possible to add another glass plate separated by a gap. In this case, because of additional gaps, inter alia, heat insulation performance and noise barrier performance can be improved.
Number | Date | Country | Kind |
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2015-100929 | May 2015 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2016/057994 | 3/14/2016 | WO | 00 |