JPH04315764A - Lamp - Google Patents

Abstract

PURPOSE:To prevent a dielectric multilayer film from being peeled from the surface of the bulb of a lamp without affecting the optical characteristic of the lamp. CONSTITUTION:A dielectric multilayer film 9 is formed via a buffer layer 8 on the outside of the bulb 2 of a lamp by deposition or dipping method, etc. The buffer layer 8 is such that stress (tensile stress) generated between the layer 8 and the surface of the bulb 2 is smaller than that which may be generated if a transparent dielectric layer of a high refractive index is directly formed on the surface of the bulb; also, the dielectric multilayer film 9 comprises a transparent dielectric layer 9a of a high refractive index laid over a transparent dielectric layer 9b of a low refractive index.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lamp having a coating such as an infrared cut filter formed on the bulb surface.

0002

[Prior Art] A high refractive index dielectric layer such as titanium oxide and a low refractive index dielectric layer such as silicon oxide are alternately laminated on the surface of a bulb by vapor deposition or dipping. A lamp designed to prevent the transmission of (infrared rays) is disclosed in Japanese Patent Application Laid-open No. 57-119454 or Japanese Patent Application Laid-Open No. 61-1989.
It has been proposed in Publication No. 190853 and the like.

0003

[Problem to be Solved by the Invention] In the above-mentioned lamp, in order to improve optical properties such as selective transmission or selective reflection of light of a predetermined wavelength, it is necessary to increase the number of dielectric layers constituting the coating. become. However, as the number of layers increases, peeling tends to occur between the bulb surface and the first high refractive index dielectric layer.

[0004] Therefore, it has been considered to add phosphorus (P) to the coating solution for forming the dielectric layer, but this would lower the refractive index of the high refractive index dielectric layer and prevent the desired result. optical properties cannot be obtained.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a coating in which a transparent dielectric layer with a high refractive index and a transparent dielectric layer with a low refractive index are laminated on the surface of a bulb made of quartz or glass. In the formed lamp, the stress generated between the bulb surface and the high refractive index transparent dielectric layer constituting the first layer of the coating is applied directly to the bulb surface. A buffer layer was interposed to reduce the stress that would occur when a transparent dielectric layer was formed.

[0006]

[Operation] By interposing a buffer layer between the bulb surface and the transparent dielectric layer with a high refractive index that constitutes the first layer of the coating, the difference in thermal expansion coefficient between the bulb and the dielectric layer can be compensated for. The resulting stress can be alleviated.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is an overall view of a lamp according to the present invention, and FIG. 2 is an enlarged sectional view of a main part of the lamp.

The lamp 1 (halogen lamp) has a filament 3, an internal lead wire 4, and a bead 5 disposed inside a bulb 2 made of quartz or glass, and the internal lead wire 4 and the external lead wire 6 are connected with a molybdenum foil 7. There is.

A buffer layer 8 is provided on the outside of the valve 2.
A dielectric multilayer film 9 is formed by a vapor deposition method, a dipping method, or the like. In the case of the dipping method, the baking treatment after coating can be performed by lighting a bulb after coating and controlling the voltage to control the temperature, which also serves as aging.

Here, the buffer layer 8 is made of a material whose stress (tensile stress) generated between the buffer layer 8 and the surface of the bulb 2 is smaller than the stress generated when a transparent dielectric layer with a high refractive index is directly formed on the bulb surface. shall be. For this purpose, the material of the buffer layer to be applied, its film thickness, firing temperature, and firing time may be appropriately selected and formed.

The dielectric multilayer coating 9 is formed by laminating a transparent dielectric layer 9a with a high refractive index and a transparent dielectric layer 9b with a low refractive index, and the transparent dielectric layer 9a with a high refractive index is made of titanium oxide ( TiO2) and silicon oxide (SiO2) as the low refractive index transparent dielectric layer 9b.

Next, specific examples and comparative examples will be given to clarify the effects of the present invention.

(Example 1) Coating liquid for forming silicon oxide film (
A film with a thickness of 200 nm was formed on the surface of the quartz bulb by dipping using MOF manufactured by Tokyo Ohka Kogyo Co., Ltd., and then thermally decomposed at 500° C. for 30 minutes in a firing furnace to obtain a buffer layer. Then, a first layer of titanium oxide having a refractive index of 2.20 was formed to a thickness of 125 nm on the surface of this buffer layer by the same dipping method, and was fired at 500° C. for 30 minutes in a firing furnace. Next, 190 nm of silicon oxide with a refractive index of 1.45 was formed as a second layer in the same manner.
The film was formed to have a thickness of m and was fired in a firing furnace at 500°C for 30 minutes. This combination is then repeated until the seventh layer of titanium oxide is reached, and the thickness of the eighth layer of silicon oxide is 95 nm.
As a result, we completed a dielectric multilayer coating. The above layer structure (
Table 1) shows the results.

[0014]

[Table 1]

In Table 1, the center wavelength refers to the wavelength at which the reflectance is closest to 1. It can be seen that the dielectric multilayer coating having the layer structure shown in Table 1 shows no peeling, and has good spectral reflectance properties as an infrared reflective coating as shown in FIG.

(Example 2) Coating liquid for forming silicon oxide film (
A film with a thickness of 190 nm was formed on the surface of the quartz bulb by a dipping method using MOF manufactured by Tokyo Ohka Kogyo Co., Ltd., and then thermally decomposed at 500° C. for 30 minutes in a firing furnace to obtain a buffer layer. Then, a dielectric multilayer coating having a layer structure as shown in Table 2 was formed on the surface of this buffer layer. Note that the formed dielectric multilayer coating has the first to eighth layers for infrared reflection with a center wavelength of 1100 nm, and the ninth to first layers for infrared reflection.
Up to six layers are used for visible light control with a center wavelength of 600 nm. The dielectric multilayer coating thus obtained was difficult to peel off and had good spectral characteristics as shown in FIG.

[0017]

[Table 2]

(Example 3) A coating solution for forming a silicon oxide film (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used as a coating solution for forming a buffer layer.
A buffer layer with a thickness of 300 nm was formed using OCD T-7) manufactured by OCD Corporation, and a dielectric multilayer film having an 8-layer structure similar to that in Example 1 was formed on this buffer layer. The dielectric multilayer coating thus obtained had no peeling and had good spectral characteristics as shown in FIG. 3.

(Example 4) A dielectric multilayer film having a 16-layer structure as in Example 2 was formed on top of the same buffer layer as in Example 3. The dielectric multilayer coating thus obtained had no peeling and had good spectral characteristics as shown in FIG. 4.

(Example 5) After forming a buffer layer in the same manner as in Example 1 except that the firing temperature was 140° C. and the firing time was 15 minutes, a 16-layer dielectric was formed in the same manner as in Example 2. When a multilayer film was formed, no peeling phenomenon was observed, and the spectral characteristics were as good as those shown in FIG. 3.

(Comparative Example 1) When an attempt was made to form a dielectric multilayer film with the same 8-layer structure as in Example 1 without forming a buffer layer, a silicon oxide layer was formed as the sixth layer, and the temperature was increased from 500°C. During cooling, peeling occurred from the interface between the quartz bulb and the first layer, making it impossible to stack any more layers.

(Comparative Example 2) Phosphorus (P) was used as a coating liquid for forming a silicon oxide film and a coating liquid for forming a titanium oxide film.
MOF P- manufactured by Tokyo Ohka Kogyo Co., Ltd. with the addition of
Si-Film P-80210 and MOF P-
Using Ti-Film P-60210, (Table 3)
A dielectric multilayer coating with an eight-layer structure and a center wavelength of 1100 nm was formed as shown in FIG. At this time, the refractive index of the silicon oxide film had decreased to 1.46, and that of titanium oxide had decreased to 2.05.

[0023]

[Table 3]

As shown in FIG. 3, the optical properties of the dielectric multilayer coating obtained above were inferior to those of Example 1 in terms of infrared reflection properties. Furthermore, in order to obtain the same characteristics as in Example 1, it was necessary to add two more layers to make ten layers.

(Comparative Example 3) OCD manufactured by Tokyo Ohka Kogyo Co., Ltd., which is made by adding phosphorus (P) to a coating solution for forming a silicon oxide film.
-80210 was used to directly form a dielectric multilayer coating with a 16-layer structure similar to that in Example 2 on the bulb surface, but a 12th layer of silicon oxide was formed, and upon cooling from 500°C. Peeling occurred from the interface between the quartz bulb and the first layer, making it impossible to stack any more layers. At this time, treatments such as roughening the surface of the quartz bulb were performed, but peeling could not be prevented.

(Comparative Example 4) A film with a thickness of 200 nm was formed on a quartz bulb using a polymer obtained by the reaction of dichlorosilane and ammonia (polysilazane manufactured by Tonen Corporation) as a coating solution for forming a buffer layer. When an attempt was made to form a dielectric multilayer film with an eight-layer structure similar to that in Example 1 on this film, a fourth layer of silicon oxide film was applied, and a
Both films peeled off from the interface between the quartz bulb and the buffer layer upon cooling from °C, making it impossible to stack them any further.

[0027]

[Effects of the Invention] As explained above, according to the present invention,
The stress generated between the bulb surface and the high refractive index transparent dielectric layer that constitutes the first layer of the coating formed a high refractive index transparent dielectric layer directly on the bulb surface. A layer whose thermal expansion coefficient is larger than that of the bulb and smaller than the first layer, a transparent dielectric layer with a high refractive index, is interposed as a buffer layer, so that the stress is smaller than that of the first layer. It is possible to prevent the dielectric multilayer coating from peeling off from the bulb surface without affecting the optical properties.

[Brief explanation of drawings]

[Fig. 1] Overall view of a lamp according to the present invention

[Figure 2] Enlarged sectional view of the main parts of the lamp

[Figure 3] Graph showing the relationship between wavelength and reflectance

[Figure 4] Graph showing the relationship between wavelength and reflectance

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Lamp, 2... Bulb, 8... Buffer layer, 9... Dielectric multilayer coating, 9a... Transparent dielectric layer with high refractive index, 9b... Transparent dielectric layer with low refractive index.

Claims (2)

[Claims] 1. A lamp in which a coating film is formed on a bulb surface made of quartz or glass, in which a transparent dielectric layer with a high refractive index and a transparent dielectric layer with a low refractive index are laminated, wherein the bulb surface and a first layer of the coating are formed on the bulb surface. The stress generated between the transparent dielectric layer with a high refractive index that makes up the eye and the surface of the bulb is greater than the stress that would occur if a transparent dielectric layer with a high refractive index was formed directly on the bulb surface. A lamp characterized by interposing a buffer layer that becomes smaller. 2. The lamp according to claim 1, wherein a material constituting the buffer layer is selected to have a refractive index approximately equal to the refractive index of the bulb.