JPH0519355A - Illuminating device - Google Patents

Abstract

PURPOSE:To increase a light quantity without making the spreading angle of light larger. CONSTITUTION:Light sources 6 and 7 are respectively arranged near a 1st focal point F1 and a 2nd focal point F2 in a reflection mirror 5 having an ellipsoidal shape. In such a case, the images at the light emitting parts of either light source and the other light source are superposed, and the size of the light emitting part is the same as that in the case of one light source, so that the light quantity is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device in a projection type display device.

[0002]

2. Description of the Related Art Generally, an illuminating device used in a projection type display device comprises a light source such as a halogen lamp and a metal halide lamp, and a reflecting mirror and a condenser lens of various shapes in order to enhance the efficiency of the light source and increase the light output. Become.

An example of the configuration of a conventional lighting device is shown in FIG.

FIG. 3A shows the case where the spherical reflecting mirror 1a is used. The light source 2 is arranged at the center of curvature, and the condenser lens 3 is arranged on the opposite side of the light source 2.

FIG. 3B shows the case where the parabolic reflector 1b is used. The light source 2 is arranged at the focal point of the paraboloid.

FIG. 3C shows the case where the elliptical reflecting mirror 1C is used. The light source 2 is arranged at the first focus, and the condenser lens 3 is arranged outside the second focus.

[0007]

Due to the widespread use of liquid crystal projectors and the like, an illumination device for projection type display devices that has high brightness and long life is becoming more and more necessary. Therefore, in order to brighten the light emitted from the lighting device, it is possible to increase the wattage of the lamp in the lighting device.

However, at that time, from the viewpoint of color rendering and reliability of the lamp, it is unavoidable to enlarge the light emitting portion of the lamp. As a result, the divergence angle of light becomes large due to the size of the light emitting portion.

In an optical system of a projector having a long optical path, a particularly large spread angle of light means that the amount of light finally reaching the screen is reduced. In other words, increasing wattage does not always lead to brightness.

In view of the above, the present invention provides an illuminating device which can be brightened without increasing the spread angle of light.

[0011]

According to item (1) above SUMMARY OF THE INVENTION are, as in FIG. 1, a reflecting mirror 5 having an elliptical sectional shape, distribution to the first focal point F ₁ and in the vicinity of the second focal point F ₂ near the ellipse The two light sources 6 and 7 are provided, and a light extraction opening 8 is formed on the front side of the reflecting mirror 5 in the irradiation direction.

A condenser lens 9 is arranged in front of the light extraction opening 8 to provide an illumination device for a projection type display device.

[0013]

The light emitted from the light source 6 arranged near the first focal point F ₁ is reflected by the elliptical surface of the reflecting mirror 5 and the second focal point F 1
Focus on around ₂ . Similarly, the light emitted from the light source 7 arranged near the second focus F ₂ is reflected by the reflecting mirror 5 and condensed near the first focus F ₁ . These lights are extracted to the outside through the opening 8 and irradiated by the condenser lens 9.

As described above, since the images of the light emitting portion of one light source lamp and the light emitting portion of the other one light source overlap with each other, the size of the light emitting portion is the same as that in the case of one light source. That is, the amount of light can be increased with the divergence angle of light being the same as when there is one light source.

[0015]

EXAMPLE An example in which the illumination device of the present invention is applied to a liquid crystal projector will be described. FIG. 1 is a sectional view of an illuminating device showing an embodiment of the present invention, and FIG. 2 is a configuration diagram of a liquid crystal projector.

The illuminating device of this embodiment comprises a reflecting mirror 5 having an elliptical surface shape, and two light sources 6 and 7 arranged near the first focus F ₁ and the second focus F ₂ of the ellipse. Thus, a light extraction opening 8 is formed on the front side of the reflecting mirror 5 in the irradiation direction.

The reflecting mirror 5 is an ordinary ellipsoidal reflecting mirror 2.
It is formed by facing each other up and down. The light sources 6 and 7 are 150 W metal halide lamps, and one light source 6 has a first focal point F in the reflecting mirror 5.
The light source 7 is arranged near ₁ and the other light source 7 is arranged near the second focus F ₂ .

The opening 8 is a circular hole located outside the second focal point F ₂ about the major axis of the ellipse of the reflecting mirror 5, and a condenser lens is provided in front of the opening 8. An optical lens 9 is provided.

As shown in FIG. 2, the optical system of the liquid crystal projector includes an illuminating device and R, G, and R, G, as optical shutters for controlling each light of red (R), green (G), and blue (B). B light liquid crystal panel 10, 11, 12
A heat ray cut filter 13 that transmits only visible light of the light emitted from the illumination device, an R reflection dichroic mirror 14 that reflects R light, and B reflection dichroic mirrors 15 and 16 that reflect B light. , G reflection dichroic mirror 17 that reflects G light, and total reflection mirrors 18 and 19
And a projection lens 20.

In the figure, 21 is a cooling fan, 22 is a hole for cooling air, and 23 is a light source support made of a translucent material.

In the above structure, when light is emitted from the light source 6 arranged near the first focal point F ₁ , the light emitted toward the opening 8 is directly emitted to the outside, and the other light is emitted from the reflecting mirror 5. Is reflected by the ellipsoidal surface of and is focused near the second focus F ₂ .

When light is emitted from the light source 7 arranged near the second focus F ₂ , it is reflected by the ellipsoidal surface of the reflecting mirror 5 except for the light directly emitted from the aperture 8, and the first focus F ₂ is emitted. Focused near ₁ . Then, similar to the light emitted from the light source 6, these lights are focused on the second focus F ₂ by the reflecting mirror 5.

As described above, the light emitted from the light sources 6 and 7 is reflected by the reflecting mirror 5 several times, so that the second focus F is obtained.
_The light is condensed to ₂ and is taken out of the reflecting mirror 5 through the opening 8.

Then, the light emitted from the illuminating device is advanced straight by the condenser lens 9, and the heat ray cut filter 1
Infrared light is cut off at 3, and is then color-separated into R, B, and G lights at an R reflection dichroic mirror 14 and a B reflection dichroic mirror 15, which are directly or totally reflected.
Are reflected by the liquid crystal panels 10, 1 of R, B, G respectively.
It is incident on 1 and 12.

The light of the image pattern of each color is transmitted through the three liquid crystal panels 10, 11 and 12, and is color-synthesized by the B reflection dichroic mirror 16 and the G reflection dichroic mirror 17 and projected forward through the projection lens 20. .

Here, the display size was enlarged and projected to 55 inches for white display, and the illuminance at the center of the screen was measured. When two 150 W metal halide lamps with an electrode distance of 5 mm were used as the light sources 6 and 7. Is about 160
There was a lux illuminance. In comparison with this, as a conventional lighting device, an ellipsoidal reflector and a distance between electrodes of 15 mm
About 90 when using 0W metal halide lamp
It was Lux. Similarly, when a 400 W metal halide lamp with a distance between electrodes of 10 mm was used in a conventional lighting device, it was about 140 lux.

Therefore, since the images of the light emitting portion of one light source and the light emitting portion of the other one light source overlap, the size of the light emitting portion is equal to that in the case of one light source. That is, the divergence angle of light can be increased almost twice as much as when the number of light sources is one, and an efficient bright illumination device can be realized.

Conversely, the divergence angle of light can be reduced without changing the brightness as compared with the case where there is only one light source.

By using such an illuminating device for a projection type display device, the amount of light is increased without enlarging the illuminating device, so that the projection type display device can be downsized.

The present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

For example, although the present embodiment is applied to the liquid crystal projector, the present invention is not limited to this and may be applied to a display device such as a rear projection type or a projector.

[0032]

As is apparent from the above description, according to the present invention, by arranging the light sources in the vicinity of the two focal points of the ellipse of the reflecting mirror having an elliptical shape, the light emitting portion of one light source and other Since the images of the light emitting parts of one light source overlap, the size of the light emitting part is the same as when there is one light source, and the divergence angle of the light is almost the same as when there is one light source It is possible to increase the number, and it is possible to efficiently realize a bright lighting device.

Further, by utilizing this illuminating device for the projection type display device, it is not necessary to enlarge the illuminating device,
The projection type display device can be downsized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a lighting device showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a liquid crystal projector.

FIG. 3 is a cross-sectional view of a conventional lighting device, and FIG.
A is a spherical reflector, FIG. 3-B is a parabolic reflector, and FIG. 3-C is an elliptical reflector.

[Explanation of symbols]

5 Reflector 6, 7 Light source 8 Aperture F ₁ First focus F ₂ Second focus

Claims (2)

[Claims] 1. An ellipsoidal reflecting mirror and two light sources arranged near a first focus and a second focus of the ellipse, and a light extraction opening is provided on the front side in the irradiation direction of the reflecting mirror. An illuminating device characterized by being formed. 2. An illumination device for a projection type display device, comprising the reflecting mirror and the light source according to claim 1, and a condenser lens disposed in front of a light extraction opening.