JPS59177850A - Tungsten halogen lamp with dichroic mirror - Google Patents

Abstract

PURPOSE:To decrease irregularities in brightness and temperature distribution on the irradiated surface by installing a tungsten halogen lamp inside a dichroric mirror having a selective reflection film on its inner surface and performing diffusion treatment on part of the bulb of the tungsten halogen lamp. CONSTITUTION:In a tungsten halogen lamp with a dichroic mirror, a tungsten halogen lamp 4 having a frost surface 7 formed by diffusion treatment on the outer surface of a bulb 6, is installed inside a dichroic mirror 3. The dichroic mirror 3 is made by forming a multilayered selective reflection film 2 having a selective reflection characteristic on the inner surface of a glass base body 1 through vapordeposition. Since light discharged from a filament 5 toward the mirror 3 is partially diffused by passing through the frost surface 7, light with a high luminance traveling from the filament 5 and light with a low lumiance traveling from the bulb surface become incident upon the point (P3) located in the inner side of the mirror 3 as well as the point (P4) located in the opening side of the mirror 3. Therefore reflected light includes both main reflected light (F3), (F4) and diffused reflected light (F'3), (F'4). As a result, irradiation can be carried out without causing any irregularity in brightness and variation in temperature distribution on the irradiated surface.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is particularly applicable to 8-screen projectors and overhead projectors.
The present invention relates to a non-volatile light bulb with a guichroic mirror for use in optical equipment such as, for example, or for general lighting in museums, stores, and the like.

Conventional structure and problems A halogen light bulb is a combination of a dichroic mirror and a halogen light bulb, and is small.
It combines the feature of a halogen light bulb with a mirror, which is the ability to maintain good light distribution performance, and the feature of being able to significantly reduce infrared radiation, which is a drawback of halogen light bulbs.

About this halogen bulb with dichroic mirror
To explain using a diagram, a single or compound ellipsoidal rotation is formed by depositing a multilayer selective reflection film 2 having selective reflection characteristics that reflects visible light and transmits infrared light on the inner surface of a compressed glass substrate 1. A halogen light bulb 4 is incorporated into a dichroic mirror 3 on the surface at a position where the desired light distribution characteristics can be obtained.

Gengas is sealed inside.

Halogen bulbs with dichroic mirrors, which are equipped with halogen bulbs with transparent pulp, have a small light-emitting area, making it easier to control light distribution and increasing the efficiency of light use.
The eccentricity of the filament or a slight shift in the filament position greatly changes the light distribution characteristics, and therefore has a significant impact on the illuminance distribution on the irradiated surface. It is also called jin, in which the shadow of the filament is reflected on the irradiated surface. For this reason, the inner surface of the mirror should be made polyhedral or have small convex or concave depressions (
Stipples (referred to as hammer marks) are provided to diffuse reflection, but if the diffusivity of the mirror is increased, it becomes difficult to control the light and the efficiency decreases, making it difficult to achieve the desired light distribution performance. Therefore, the mirror should be made diffusive (there is a limit).

With mirrors such as aluminum vapor-deposited mirrors or aluminum mirrors.
・The distribution temperature of the Rogen bulb is almost the same as the distribution temperature of the Rogen bulb itself, but in the case of the Rogen bulb with a dichroic mirror, the temperature distribution is
The distribution temperature is generally several tens of K (Kelvin) higher than that of a rogen bulb alone. Furthermore, the distribution temperature varies depending on the direction of light irradiation, and generally the distribution temperature increases as the distance from the optical axis increases, and depending on the dichroic mirror, the light color becomes bluish. This is because the spectral reflectance of the dichroic mirror is not constant and changes depending on the wavelength. Furthermore, the spectral reflection characteristics of this mirror vary greatly depending on the thickness of the reflective film and the angle of incidence of light. FIGS. 2 and 3 show changes in the transmission characteristics of the dichroic mirror with respect to the thickness of the reflective film and the angle of incidence.

As the thickness of the reflective film increases and the angle of incidence increases, the reflective film will allow more light on the long wavelength side to pass through, so the long wavelength side will be cut off as reflected light, and the light color will be bluish. (distribution temperature becomes higher).

The following and generalization will be explained. FIG. 4 shows radiation paths of light (visible light and infrared light) in the case of an elliptical rotating mirror. The light emitted from the filament 5 is converted into visible light F1 by the multilayer reflective film 2. The light is separated into two components: F2 and infrared light IR1 and IE2, and mainly only visible light is emitted to the front surface of the mirror. In this case, even if the thickness of the multilayer reflective film 2 is the same on the rear side P1 and the opening side P2 of the mirror, the distance through which light passes is longer on P2 and is equivalent to an apparent thicker reflective film.

Therefore, the distribution temperature of the reflected light F2 from P 2 becomes high. In an elliptical rotating mirror, the reflected light F1 from the rear side P is irradiated in the optical axis direction, and the reflected light F2 from the aperture side P2 is irradiated in a direction away from the optical axis, so the distribution temperature increases as the distance from the optical axis increases. , for example, in the case of 3050 at the center of the optical axis,
It becomes 3200-3300 in the peripheral direction. The reflective film is made by alternately depositing two compounds with different refractive indexes many times, and it is very likely that unevenness in film thickness (deposition unevenness) will occur, not only between mirrors but also locally on a single mirror. The film thickness is uneven. Norogen light bulbs with glaucroic mirrors that use mirrors with large film thickness irregularities are not suitable for illumination because the irradiated surface becomes partially reddish or bluish. A difference of 50 degrees in distribution temperature can be discerned by the human eye, while a difference of 200 degrees or more poses a problem in use. Especially those with dichroic mirrors.
In the case of rogen light bulbs, as the temperature distribution increases, the light color becomes yellowish or greenish, resulting in extremely poor color rendering. In this way, a gicroic mirrored norogen bulb incorporating a transparent pulp bulb has a large effect on the light distribution characteristics due to filament eccentricity and filament misalignment, and the filament casts a shadow on the irradiated surface. etc., making it difficult to obtain illumination with even brightness. Further, unevenness in light color is likely to occur due to unevenness in the thickness of the reflective film of the dichroic mirror, and furthermore, unevenness in light color is also likely to occur at the center and periphery of the optical axis of the irradiated surface.

Purpose of the Invention The present invention reduces the influence of filament eccentricity, filament misalignment, etc. on delivery characteristics, provides illumination with less uneven brightness, and at the same time reduces the variation in light color due to unevenness in the reflective film thickness of a dichroic mirror. To provide a dichroic mirror-equipped non-rogen light bulb which has good illumination effects with a small amount of light.

Structure of the Invention The present invention has a structure in which a selective reflective film is formed on the inner surface of the dichroic mirror, and a halogen bulb with diffusion treatment applied to at least a portion of the surface of the pulp is provided inside the dichroic mirror, and the mirror and the halogen bulb are integrated. In this case, the light emitting state of the halogen bulb is diffused to the extent that the filament is almost invisible, so the light emitting part of the filament is enlarged and the brightness (brightness) of this part is also significantly reduced. Furthermore, the bulb surface around the filament also shines due to scattered light and the light emitting area becomes larger. This is the first halogen light bulb with dichroic ink mirror! (The 1-bright characteristic combines two features: the light-condensing light distribution characteristic by the high-intensity light emitting part with a small area and the diffused light distribution characteristic by the low-intensity light-emitting part H15 having a large area.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below using the meat side.

FIG. 5 is a sectional view of a halogen light bulb with a dichroic mirror, which is an embodiment of the present invention. As shown in the figure, this halogen light bulb with a dichroic mirror includes a multilayer selective reflection film 2 having selective reflection characteristics on the inner surface of a glass substrate 1.
A halogen light bulb 4 whose outer surface of a bulb 6 is subjected to diffusion treatment to form a frosted surface 7 is provided inside a dichroic mirror 3 formed by vapor deposition. To form the 70 stroke surface of the bulb 6, the outer surface of the bulb 6 is roughened mechanically by sandblasting or the like, or chemically by roughening with butic acid or the like.

Figure 6 is an explanatory diagram of the Dyke R-Fickmiller Ice halogen bulb when this bulb is used, and the filament 5
The light emitted from the direction of the dichroic mirror 3 (:
is partially diffused by passing through the frost surface 7. Therefore, the light from the high brightness part of the filament 5 and the light from the low brightness part from the bulb surface (diffused light) also enter the point P3 on the back side of the mirror and the point P4 on the opening side. These reflected lights include the strong main reflected light F3. 2 of F4 and weak diffuse reflection light F3', F4'
Contains 1f1. Ru.

Among these, the main reflected light F3. F4 obtains the brightness and spread of brightness necessary for a non-rogen light bulb with a luminescent mirror, and diffuse reflected light F3/, F
4/ serves to reduce unevenness in brightness and variation in temperature distribution. FIG. 7 shows an example of the light distribution curve of a halogen light bulb with a dichroic mirror, where curve E is a conventional halogen light bulb with a transparent bulb, and curve F is a halogen light bulb whose outer surface is diffused. The light distribution curve of a transparent halogen bulb is uneven and has poor axial symmetry.

On the other hand, in the case of a halogen bulb that has undergone diffusion treatment, the center luminous intensity is slightly lower, but the curve has less fluctuation and has good axial symmetry. Comparing the lighting conditions of the two bulbs, it is clear that they have been treated with diffusion treatment...The Rogen bulb has less uneven lighting, and the illuminance changes gradually from the center of the optical axis, giving a visually uniform feeling. receive.

A comparison of the difference in temperature distribution between the center of the optical axis and the periphery within the same irradiated surface of a conventional halogen bulb with a transparent bulb and a halogen bulb with a dichroic mirror incorporating a halogen bulb with diffusion treatment on the outer surface of the bulb revealed that the transparent In the case of a halogen bulb, which has a diffused temperature of 150 to 200 in the case of a norogen bulb, the difference in temperature distribution decreases to 90 to 130. In addition, non-uniformity in temperature distribution due to local variations in the thickness of the selective reflective film can be greatly improved with diffusion-treated halogen bulbs, and it is not practical to use dichroic mirrors with some variation in film thickness. Variations in temperature distribution can be suppressed to a non-problematic level.

As for the method of imparting diffusivity to the bulb surface of a halogen light bulb, a heat-resistant white paint film may be formed, and similar effects can be expected by applying these diffusion treatments to a portion of the bulb. In addition to glass, the substrate on which the selective reflection film is entirely formed may be made of a heat-resistant material that transmits infrared rays, such as resin or ceramic.

Effects of the Invention As described above, by diffusing at least a portion of the surface of the halogen bulb provided inside the dichroic mirror formed on the entire surface of the selective reflection film, the radiation from the filament, t'1. The light is diffused by the bulb surface, and the light emitting part of the halogen bulb is expanded from the filard to the entire surface of the bulb. For this reason, a large amount of diffused light from the bulb surface enters the dichroic mirror, so that high-quality illumination with less unevenness in brightness and less variation in temperature distribution can be obtained on the illuminated surface.

Moreover, the light distribution characteristics are less affected by eccentricity or deformation of the filament, resulting in stable/reading quality. Also, change the dichroic mirror shape to polyhedron +c 1. A predetermined light distribution performance can be obtained without special processing such as providing small convex or concave holes.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the structure of a conventional halogen light bulb with a dichroic mirror, Figures 2 and 3 are diagrams showing the spectral transmittance of the dichroic mirror, and Figure 4 is an explanatory diagram of a conventional light bulb with a dichroic mirror. FIG. 5 is a structural sectional view of a halogen light bulb with a dichroic mirror according to the present invention, FIG. 6 is an explanatory diagram thereof, and FIG. 7 is a diagram showing a light distribution curve. 1 glass substrate, 2...selective reflective film, 3...
Dichroic mirror, 4...Halogen'ε bulb. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
blatantly
Saddle 2

Claims (1)

[Claims] A halogen light bulb with a dichroic mirror, characterized in that a halogen light bulb is provided inside a dichroic mirror having a selective reflection film formed on the inner surface, and a diffusion treatment is applied to at least a part of the surface of the bulb of the halogen light bulb.