JPH08235919A - Lighting system - Google Patents

Abstract

PURPOSE: To provide uniform illumination distribution in a projection plane. CONSTITUTION: A multilayer reflecting film 15 on a reflecting mirror 12 on which a halogen lamp 17 is arranged with the emission part axis P of a filament 19 directed perpendicular to the light axis Z is thicker than a part perpendicular to the emission part axis P in an area in the direction of the emission part axis P of the filament 19. In this way, the filament 19 has the outgoing light amount to the direction of the emission part axis P less than the outgoing light amount to the perpendicular direction of the emission part axis P, but the reflecting mirror 12, which has the multilayer reflecting film 15 thicker in an area in the direction of the emission part, axis P of the filament 19 to enhance its reflecting strength, is reduced in irregular projection light, reflected by the reflecting mirror 12, by a complemental relationship between the outgoing light amount and the reflecting strength to provide uniform illumination distribution in a projection plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device having a reflecting mirror whose illuminance distribution on a projection surface is substantially uniform.

[0002]

2. Description of the Related Art Conventionally, a high output lamp with a reflecting mirror has been used in an illuminating device such as a spotlight for shops, an OHP, an illuminating device as a light source of a liquid crystal projector, and the like. In this high-output lamp with a reflector, a light source such as a high-output halogen lamp or a small-sized short arc metal halide lamp is arranged in a concave reflector, and the light from the light source is emitted forward by the reflector to obtain a desired distribution. I try to get the light characteristics.

As shown in the sectional views of the first and second conventional illuminating devices in FIGS. 7 and 8, normally, in the high power lamps 1 and 2 with a reflecting mirror of the illuminating device of this type, a uniform light is emitted. The inner surfaces, which are the reflecting surfaces of the concave reflecting mirrors 3 and 4, are made spheroidal or paraboloidal so that radiation can be easily obtained, and the coiled filament 6 of the high-output halogen lamp 5 of the light source is formed.
And the discharge path 8 of the short arc metal halide lamp 7.
Is positioned near the focal points of the reflecting mirrors 3 and 4 along the optical axis direction.

Further, a comparatively large illuminating device used for outdoor illumination, an illuminating device used for spotlights, etc. are disclosed in Japanese Patent Laid-Open No. 5-289022 and Japanese Utility Model Publication 2-15.
As described in Japanese Laid-Open Patent Publication No. 213, some lamps are arranged such that the discharge path and the axial direction of the coil-shaped filament coincide with each other in the direction orthogonal to the optical axis of the reflecting mirror.

In such a lamp with a reflecting mirror, it is ideal that the light emitting portion is a point, but in reality, the discharge path of the light emitting portion, the filament and the like are linear light emitting portions having a length. The lamp as the light source is different from the point light source as the ideal light source. For this reason, the light emitting unit is made as small as possible so as to be as close to the point as possible, and the light emitting unit is devised so that ideal projection light can be obtained by correcting the shape of the reflecting mirror or the like.

For example, in the case where the lamp is arranged so that the linear light emitting portion overlaps with the optical axis of the reflecting mirror, the focal point of the reflecting mirror is deviated along the optical axis by the length of the light emitting portion. However, in the case of the circular reflecting mirror, the influence of the deviation from the focus position appears evenly in the entire circumferential direction of the projection light reflected by the reflecting mirror, and this is not a serious problem.

On the other hand, the above-mentioned Japanese Unexamined Patent Publication No. 5-28290
In the case of a lamp with a reflecting mirror or the like in which a linear light emitting portion has its axial direction orthogonal to the optical axis of the reflecting mirror, as described in Japanese Patent Publication No. 2 and Japanese Utility Model Publication No. 2-15213. The deviation from the focal point of the linear light emitting unit is not in the optical axis direction, and the amount of light emitted in the axial direction is relatively weaker than the amount of light emitted in the direction orthogonal to the axis of the linear light emitting unit.

The projection light emitted from the linear light emitting portion in each direction, reflected by the reflecting mirror, and projected in the forward direction causes unevenness in illuminance depending on the portion projected on the projection surface. For example, even if the projection light reflected by the reflecting mirror is made uniform in the central portion of the projection surface, it tends to be non-uniform with unevenness in the vertical and horizontal directions in the peripheral portion. It was

The influence of unevenness of the illuminance due to the projected portion on the projection surface is such that, in general illumination, the arc length formed in the discharge path of the light emitting portion or the effective light emission length of the filament is formed to be relatively short. However, it has not been a problem.

However, in a lighting device used for a light source of a liquid crystal projector or a projector, lighting of a museum, or the like,
It is necessary to perform uniform projection on a projection surface such as a screen placed at a predetermined distance, and it is not preferable that the projection light becomes uneven and the illuminance distribution on the projection surface becomes uneven. That is, in the illuminating device, even if the illuminance in the central portion of the projection surface is slightly higher than that in the peripheral portion, it is unlikely to be a problem from the viewpoint of the illumination effect, but there is a difference in the illuminance in the vertical and horizontal directions in the peripheral portion. Is not desirable, and it is required to minimize the difference.

It should be noted that the one disclosed in the above-mentioned Japanese Laid-Open Patent Publication No. 5-282902 considers heat dissipation by changing the characteristics of the reflecting surface of the reflecting mirror between the neck side and the flange side, and is actually fair. No. 2-15213 discloses that the thickness of the multilayer film on the inner surface is changed between the neck side portion and the flange side portion of the reflecting mirror to eliminate the color tone variation between the center of the projected light and the outer peripheral portion. However, it does not eliminate the non-uniformity of the projection light generated on the projection surface.

[0012]

As described above, a light source having a linear light emitting portion such as a discharge path or a filament is reflected so that the axial direction of the linear light emitting portion is a direction intersecting the optical axis of the reflecting mirror. In the illuminating device arranged on the mirror, the projection light reflected by the reflecting mirror has unevenness and the illuminance distribution on the projection surface is non-uniform. The present invention has been made in view of such a situation, and an object of the present invention is to provide an illumination device in which unevenness of projection light is reduced and the illuminance distribution in the projection surface is made uniform.

[0013]

The illuminating device of the present invention includes a reflecting mirror in which a reflecting film is applied to the inner surface of a spheroid or a paraboloid of revolution that is widened toward the front opening. In a lighting device configured by arranging a light source having a linear light emitting portion orthogonal to the optical axis of the reflecting mirror, the film thickness of the reflection film on the inner surface of the reflecting mirror is linear in the axial direction portion of the linear light emitting portion. It is characterized in that it is thicker than the portion in the direction orthogonal to the axis of the light emitting portion and has a distribution in the circumferential direction of the reflecting mirror. When is set to 1,
The axial part has a thickness of 1.05 to 1.2, and the inner surface of the spheroid or the paraboloid of revolution which is widened toward the front opening is covered with the reflective film. In a lighting device in which a light source having a linear light emitting portion orthogonal to the optical axis of the reflecting mirror is arranged in the attached reflecting mirror, a reflecting film on the inner surface of the reflecting mirror is provided in a portion orthogonal to the axis of the linear light emitting portion. In comparison, the visible light reflectance in the axial direction portion of the linear light emitting portion is high, and further, the light source is a discharge lamp, and further, the light source. Is a halogen lamp.

[0014]

In the illuminating device constructed as described above, the film thickness of the reflection film of the reflecting mirror in which the axial direction of the linear light emitting portion of the arranged light source is orthogonal to the optical axis is the axis of the linear light emitting portion. The directional part is thicker than the axially orthogonal part. As a result, the amount of light emitted in the axial direction of the linear light emitting unit is weaker than the amount of light emitted in the direction orthogonal to the axis of the linear light emitting unit, but the reflecting mirror has a film thickness of the reflective film in the axial direction portion of the linear light emitting unit. The thickness is thicker and the reflection intensity is higher. Due to the complementary relationship between the amount of emitted light and the reflection intensity, the unevenness of the projection light reflected by the reflecting mirror can be reduced, and the illuminance distribution on the projection surface can be made uniform.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 is a front view, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 3 is a diagram showing a film thickness ratio of a reflective film of a reflecting mirror, and FIG. 4 is an illuminance measuring optical system. It is a block diagram of a system, FIG. 5 is a figure which shows the screen of an illuminance measuring optical system, and FIG. 6 is a top view of another light source.

In FIG. 1 to FIG. 3, 11 is a halogen lamp with a reflecting mirror which is an illuminating device, and the reflecting mirror 12 is a spheroidal surface or a paraboloid of revolution which is expanded toward a circular front side opening 13. The reflective base 14 has an inner surface, and the multilayer reflective film 15 adhered to the inner surface of the reflective base 14. A halogen lamp 17 of a light source is fixed to a neck portion 16 at a rear portion of the reflecting mirror 12 with a heat resistant adhesive 18.

In the halogen lamp 17, a coiled filament 19 is sealed inside a bulb 20 made of glass, and terminals 22 exposed to the outside are connected to both ends of the filament 19 via lead portions 21. There is. The halogen lamp 17 is fixed so as to be located near the focal point of the reflecting mirror 12, and is arranged so that the direction of the light emitting portion axis P of the filament 19 is orthogonal to the direction of the optical axis Z of the reflecting mirror 12. .

On the other hand, the reflective mirror 12 is formed by depositing a multilayer reflective film 15 on the inner surface of the reflective substrate 14 by a vacuum deposition method. The multilayer reflective film 15 has a film structure of the reflective substrate 14+ [HL] ⁶ [H 'L'] ⁶ + air H: 1 / 4λ film of zinc sulfide (λ = 720 nm) L: 1 / 4λ film of magnesium fluoride (λ = 720n)
m) H ': 1 / 4λ film of zinc sulfide (λ = 530 nm) L': 1 / 4λ film of magnesium fluoride (λ = 530n)
m).

The film formation is performed as follows. That is, in the vapor deposition, the chamber was evacuated to 4 × 10 ⁻³ Pa and the thin films of magnesium fluoride and zinc sulfide were alternately changed to 12
Layers are formed, and then 12 layers are formed by changing the film thickness. At the time of this film formation, a correction plate is installed between the reflection substrate 14 and the vapor deposition source in the chamber, and adjustment is performed so that the film thickness distribution is optimized while changing its shape and position.

The multilayer reflective film 15 of the alternating layers of magnesium fluoride and zinc sulfide thus formed has a final total film thickness in the portion of the filament 19 in the direction of the light emitting portion axis P shown in FIG. The film thickness in the X region and the X'region is 1.05 to 1.2 times thicker than the film thickness in the Y region and the Y'region, which are portions of the filament 19 in the direction orthogonal to the light emitting portion axis P. , The X region and the X'region have higher reflection intensity. The change in the film thickness ratio in the circumferential direction of the broken line circle Q shown in FIG. 1 is as shown by the curve B in FIG. 3, and the film thickness ratio is maximum at X and X ′, Y and Y. ′ Is the smallest.

Next, the light distribution characteristic of the halogen lamp 11 with a reflecting mirror having the above-described structure was evaluated by the illuminance measuring optical system 23 shown in FIG. The illuminance measuring optical system 23
A lamp holder 24 for setting the halogen lamp 11 with a reflecting mirror, which is an illuminating device to be measured, and an optical axis W of the illuminating device to be measured.
A condenser lens 25, an aperture 26, a projection lens 27, a screen 28, a illuminance meter 29 with a viewing angle of 1 degree, and a power supply 30 for turning on the illumination device to be measured are arranged in this order in the upward projection direction.

The screen 28 is vertically and horizontally divided into three equal parts, and is divided into nine sections (a), (b), (c), (d),
Divided into (e), (f), (g), (h) and (i),
The illuminance of each section is measured by the illuminometer 29. The size of the screen 28 is 810 mm × 61.
0 mm, illuminating device under test and condenser lens 25
The distance between the condenser lens 25 and the aperture 26 is 16 mm, the distance between the aperture 26 and the projection lens 27 is 135 mm, the distance between the projection lens 27 and the screen 28 is 2500 mm, and the illuminance meter 29 is the screen. 28 to 1000 mm-1500 mm
The illuminance is measured at the position.

As the halogen lamp 11 with a reflecting mirror, for example, a reflecting mirror 12 having a diameter of 50 mm is provided with 82V, 410.
A halogen lamp 17 of W is fixed, and is set in the lamp holder 24 so that the direction of the light-emitting portion axis P of the filament 19 is horizontal, and the screen 28 is divided into 9 sections (a), (b), (c). , ..., (h), (i) were measured, and the measurement results were as shown in (Table 1). At the same time, the same structure as the halogen lamp 11 with a reflecting mirror is prepared except that the thickness of the multilayer reflecting film is the same on the entire surface of the reflecting mirror. It is shown in (Table 1).

[0024]

[Table 1]

As a result, in the comparative example, the illuminances in the regions (b) and (c) are relatively lower than those in the regions (d) and (f), whereas in the embodiment, the illuminances are (d) and (f). )region,
The areas (b) and (c) showed almost the same illuminance.

As described above, according to this embodiment, the reflecting mirror 1
Since the reflection intensity is increased by forming the film thicknesses in the X region and the X ′ region of the filament 19 of No. 2 corresponding to the direction of the light emitting portion axis P, the complementary relationship between the amount of light emitted from the halogen lamp 17 and the reflection intensity. The unevenness of the projected light can be reduced, and the illuminance distribution on the screen 28, that is, the projection surface can be made uniform.

In the above embodiment, the halogen lamp 17 is used.
The halogen lamp 11 with a reflecting mirror in which the above is fixed to the reflecting mirror 12 has been described, but a lamp with a reflecting mirror may be configured using a single-base metal halide lamp 31 as shown in FIG. 6 as a light source. In this structure, an arc is formed in the discharge path 34 between the opposing electrodes 33a and 33b sealed in the bulb 32, and the film thickness of the multilayer reflective film on the inner surface of the reflecting mirror (not shown) to which the metal halide lamp 31 is fixed is 33a, 3
3b, that is, a portion of the discharge path 34 of the linear light emitting portion in the direction of the light emitting portion axis P'is thicker than a portion in the direction orthogonal to the light emitting portion axis P '. Reference numeral 35 is a base, and 36 is a terminal.

As a result, the degree of reflection of the reflecting mirror is increased at the light emitting portion axis P'of the discharge path 34, unevenness of the projected light is reduced as in the halogen lamp 11 with a reflecting mirror, and the illuminance on the projection surface is reduced. The distribution can be made uniform. The film thickness distribution of the multilayer reflective film of the reflecting mirror is adjusted, for example, within the above range so that an appropriate illuminance distribution can be obtained according to the characteristics of the light source used.

Further, when a lamp with a reflecting mirror is constructed by using a discharge lamp of both caps as a light source, similarly, the film thickness of the multilayer reflecting film on the inner surface of the reflecting mirror is the axial direction of the light emitting portion of the discharge path which is a linear light emitting portion. Therefore, it may be provided so as to be thicker than the portion in the direction orthogonal to the light emitting unit axis.

Further, in the above-mentioned embodiment, the reflecting mirror 12 having the circular opening on the front side 13 is used. However, when a double-base halogen lamp or a double-base discharge lamp is used as the light source, it is adjusted to the shape of the light source. Alternatively, a reflecting mirror having an oblong or square front opening may be used.

In a lamp with a reflecting mirror, the reflecting surface corresponding to the base side is also provided with a reflecting characteristic,
By forming the base-side reflecting surface relatively thick to increase the reflection intensity, it is possible to enhance the reflected light from the base-side reflecting surface that emits a small amount of light emitted from the light source.

[0032]

As is apparent from the above description, according to the present invention, the film thickness of the reflection film of the reflecting mirror in which the axial direction of the linear light emitting portion of the arranged light source is orthogonal to the optical axis is linear light emission. Since the axial portion of the portion is thicker than the axially orthogonal portion, the unevenness of the projection light is reduced, and the illuminance distribution on the projection surface can be made uniform.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a diagram showing a film thickness ratio of a reflecting film of a reflecting mirror according to an embodiment of the present invention.

FIG. 4 is a configuration diagram of an illuminance measuring optical system.

FIG. 5 is a diagram showing a screen of an illuminance measuring optical system.

FIG. 6 is a plan view of another light source according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view of a first conventional lighting device.

FIG. 8 is a cross-sectional view of a second conventional lighting device.

[Explanation of Codes] 11 ... Halogen Lamp with Reflecting Mirror 12 ... Reflecting Mirror 13 ... Front Side Opening 15 ... Multilayer Reflective Film 17 ... Halogen Lamp 19 ... Filament P ... Light Emitting Axis Z ... Optical Axis

Claims (5)

[Claims] 1. A linear mirror perpendicular to the optical axis of the reflecting mirror is provided in a reflecting mirror in which a reflecting film is applied to the inner surface of a spheroidal surface or a paraboloid of revolution that spreads toward the front opening. In a lighting device configured by arranging a light source having a light emitting portion, a film thickness of a reflective film on the inner surface of the reflecting mirror is thicker in an axial direction portion of the linear light emitting portion than in an axial orthogonal portion of the linear light emitting portion. An illumination device having a distribution in the circumferential direction of the reflecting mirror. 2. The film thickness of the reflective film is 1.05 to 1.
The lighting device according to claim 1, wherein the lighting device is 2. 3. A line perpendicular to the optical axis of the reflecting mirror is formed in a reflecting mirror having a reflecting film coated on the inner surface which is a spheroidal surface or a paraboloid of revolution which is widened toward the front opening. In a lighting device in which a light source having a linear light emitting portion is arranged, the reflective film on the inner surface of the reflecting mirror reflects visible light in the axial direction portion of the linear light emitting portion as compared with the axial direction orthogonal portion of the linear light emitting portion. A lighting device characterized by a high rate. 4. The lighting device according to claim 1 or 3, wherein the light source is a discharge lamp. 5. The lighting device according to claim 1 or 3, wherein the light source is a halogen lamp.