JP2003262795A - Illuminator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminator which uses a solid light source and outputs light having uniform intensity distribution by simple constitution. <P>SOLUTION: In the illuminator 10, an illumination panel 12 having LED elements 14R to 14B to be a light source arranged in the state of an array is arranged on the side of the entrance 23 of a rod lens 20 whose cross section is square and whose inner surface is reflective. Light beams 71R to 71B are supplied without waste to the inside of the rod lens 20 from the LED elements 14R to 14B arranged at the entrance 23 of the rod lens 20 and further repeat multiple reflection within the rod lens to output homogenized light, thereby the illuminator 10 of high using efficiency of light is provided by simple constitution. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device capable of outputting light for color display by using a solid light emitting element such as an LED element as a light source.

[0002]

2. Description of the Related Art In an image display device such as a projector,
In order to display in color, light from a white light source is time-divided into three primary colors by a rotary color filter, and in synchronization with this, light valves are modulated for each color to form a color image.

[0003]

In the method using the color filter, a rotary type color filter having a disc-shaped radial region from the center of rotation, in which regions for transmitting each color are divided, is rotationally driven by a motor. Time-division into primary colors. Therefore, the optical paths of the respective colors are common, and the illumination part for outputting the light of the respective colors for display can be relatively compacted.

However, in the rotary filter, it is necessary to turn off the image display in the vicinity of the boundary of each color in order to prevent color mixture near the boundary, and the light utilization efficiency is reduced. Further, the color balance is uniquely determined by the filter and cannot be changed. Further, even though the optical path is compact, the rotary color filter also requires a motor, and a space for the motor is required, which makes it difficult to reduce the size. There is also a problem that noise of the motor is generated when the color filter is rotated.

On the other hand, there is an illuminating device using a solid light emitting element such as an LED. In recent years, a blue LED element has been put into practical use, and is an illumination device of a type that uses three-color LED elements that emit light of each color as a light source. This illumination device has the advantages that the life of the light source is long and the response speed of ON / OFF is fast, so that the color balance can be adjusted by ON / OFF. Further, there is an advantage that a color filter is unnecessary. Therefore, the utilization efficiency of light is high, and problems such as noise do not occur.

However, since the solid-state light-emitting element has a small light-emitting area, it is difficult to uniformly irradiate the light emitted from the solid-state light-emitting element on the surface of a light valve such as a liquid crystal or a mirror device. For example, it is necessary to control the spread of the light beams output from each of the light emitting elements using an expensive lens array so that they overlap each other. Since the color of the light output is different for each light emitting element and the relative luminous efficiency is also different, the lens array can be designed according to the number of light emitting elements required for each color, or the integration can be performed for each color. An expensive dichroic prism or the like is required to combine the emitted light. Therefore, even if the solid-state light emitting element is used, the illumination device is not necessarily compact and cannot be provided at low cost.

In view of the above, the present invention provides an illuminating device using a solid-state light emitting element, which has a low cost, a compact structure, and a high light utilization efficiency, and can display a bright, clear and high-quality color image. The purpose is to provide a projector.

[0008]

In a light guide whose periphery is surrounded by a reflective surface, the input light repeats multiple reflections on the peripheral surface, and at the exit of the light guide, the cross section of the light guide is crossed. The intensity distribution is almost uniform in the direction. Therefore, in the present invention, by simply arranging the solid-state light-emitting elements on the entrance side of the light guide path, it is possible to obtain the light beams of different colors integrated from the exit of the light guide path. That is, in the lighting device of the present invention, a light guide path having a rectangular cross section and an inner surface having reflectivity, and a plurality of types of solid state light emitting elements for emitting light of different colors are orthogonal to the light guide path on the incident side of the light guide path. And a lighting panel arranged in an array so as to form a plane.

Since this light guide path itself functions as an integrator or a rod lens, a light emitting element is arranged at the entrance of the light guide path so that the brightness or intensity (light amount) distribution in the cross-sectional direction is obtained from the exit of the light guide path. It is possible to obtain a uniform or nearly uniform luminous flux. Therefore,
By arranging the required number of solid-state light-emitting elements of each color on the entrance side of the light guide path, it is possible to obtain a light flux of each color with a uniform intensity distribution from the exit side. Therefore, without using an expensive optical element such as a lens array corresponding to each solid-state light-emitting element, the solid-state light-emitting element is used with an extremely simple configuration,
It is possible to provide an illuminating device capable of outputting a light flux of each color having a uniform intensity distribution.

Further, since the lighting device of the present invention uses the solid-state light emitting element as a light source, the color balance can be easily adjusted, the durability is high, and the light utilization efficiency is high. It has all the advantages of a lighting device that uses elements. For example, by providing a control unit that emits light by changing the irradiation timing and time for each type of solid state light emitting device, the color balance can be adjusted by intermittently lighting the solid state light emitting devices individually or as a whole, In addition to red, blue, and green, it is also possible to sequentially output white by simultaneous emission of all three colors within the time of one frame. Therefore, it is possible to easily perform color adjustment according to the usage environment, the business scene, the cinema scene, or the like.

Therefore, in a projector having the illuminating device of the present invention, a light valve that modulates the luminous flux output from the illuminating device to form an image, and a projection lens that projects the light from the light valve. , High light utilization efficiency, bright and beautiful color image can be displayed. The light valve is not limited to a transmissive type such as a liquid crystal, but a reflective type light valve such as a micromirror device can be adopted.

In order to make the light emitted from the plurality of solid state light emitting elements leak into the light guide path efficiently without leaking the light, the lighting panel is formed in an array form so that the solid light emitting elements form a plane orthogonal to the light guide path. It is desirable to place it in. With such an arrangement, the light output from each solid-state light emitting element can be input to the light guide path without being diffusely reflected or absorbed by the adjacent solid-state light emitting element. Also, when a plurality of solid state light emitting elements that output light of the same color are arranged, in order to obtain light with a more uniform intensity distribution from the output of the light guide, regular reflection should be performed on the surface around the light guide. To prevent it, it is desirable to arrange them randomly on the lighting panel. In order to output multi-color (full color) light, it is desirable to change the number (number) of elements that emit each color according to the relative luminous efficiency, etc., and arrange a plurality of solid state light emitting elements with low relative luminous efficiency. Will be required.

The outer size of the illumination panel can be set arbitrarily, but it is desirable that it is the same as or similar to the outer size of the light valve that switches the light flux emitted from the light guide path to form an image. That is, it is desirable to adopt an illumination panel having the same aspect ratio as the aspect ratio (aspect ratio) that defines the outer shape of the light valve. With this illumination panel, it is possible to employ a light guide path having a cross-sectional size aspect ratio equal to that of the light valve. And if the light guide paths have the same aspect ratio,
The aspect ratio of the light beam output from the outlet in parallel or while being expanded is the same as the aspect ratio of the light guide path, so the light output from the light guide path can be irradiated onto the light valve without waste, thus improving the light utilization efficiency. It gets even higher. In general, since the light output from the light guide path spreads, it is desirable that the cross section size of the light guide path is smaller than that of the light valve.

On the other hand, when the external size of the lighting panel and the aspect ratio of the cross-sectional size of the light guide path are different from the aspect ratio of the light valve, a cylindrical lens or toroidal lens is provided between the light guide path and the light valve. By enlarging or reducing in one direction, a light beam output from the light guide path at an appropriate radiation angle can be irradiated onto the light valve without waste.

When a device for switching by changing the angle of the mirror is adopted as the reflection type light valve, the reduction ratio in the switching direction is made small or the enlargement ratio is made large, and the reduction ratio in the direction perpendicular to the switching direction is made small. Increase or decrease the enlargement ratio. This reduces the angular distribution in the switching direction with respect to the direction perpendicular to the switching direction, increasing the resolution,
In addition, it becomes easier for the projection light to swallow the switched light.

Further, by providing a curved reflection panel such as an elliptical reflector, the luminous flux from the illumination panel can be efficiently guided to the light guide path. In this case, in order to prevent light leakage, it is desirable that the exit side end of the reflection panel is formed so as to be connected to the entrance side of the light guide path. Furthermore, by forming a fine structure on the reflecting surface of the reflecting panel, that is, by blazing the reflecting surface, the angle of the light beam emitted toward the light valve can be reduced, and the light utilization efficiency can be further improved.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a lighting device 1 of the present invention.
A schematic configuration of a projector 1 having 0 is shown. This projector 1 includes an illumination device 10 of the present invention, a light valve 50 that modulates a red light beam 72R, a green light beam 72G, and a blue light beam 72B emitted from the illumination device 10, and a light valve 50 that modulates the light valve 50. And a lens system 52 for forming a color image on the screen by irradiating the screen 55 with the luminous flux 73. In the projector 1 of this example, as the light valve 50, a micromirror device in which micromirrors that change the reflection direction of incident light and switch light of each pixel are arranged in an array is adopted.

As shown in FIG. 2, the illuminating device 10 has a prismatic light guide path 2 having a rectangular cross section and a reflective inner surface 21.
0, and since the incident light is multiple-reflected inside the light guide 20 to make the intensity uniform, the light guide 20
Are sometimes called rod lenses or integrators. Therefore, hereinafter, it will be referred to as a rod lens. An illumination panel 12 serving as a light source is attached to the entrance 23 side (incident side) of the rod lens 20.
The illumination panel 12 is provided on the incident side 23 of the rod lens 20,
An LED element (solid-state light emission) that includes a plane 13 orthogonal to the longitudinal direction of the rod lens 20 and outputs red light 71R, green light 71G, and blue light 71B to the plane of the rod lens 20 on the plane 13 is provided. Element) 14R, 1
4G and 14B are arranged in an array or matrix. Further, a plurality of LED elements 14 for each color
R, 14G, and 14B are arranged, and the elements of each color are randomly arranged. That is, the current L
Since the ED elements have different luminosity sensitivities for each color, it is necessary to change the number for each color in consideration of color balance. For example, red LED element 14R, green L
The ED elements 14G and the blue LED elements 14B are randomly arranged at a ratio of 2: 7: 1 based on the relative luminous efficiency.

The lighting device 10 includes these LED elements 14
The control section 40 is provided which can intermittently emit light or continuously emit R to 14B by changing the timing and time of irradiation (light emission) for each type, that is, for each LED element group of each color. The control unit 40 can drive the LED elements 14R to 14B in synchronization with a signal from the image control device 59 that controls the light valve 50. Therefore, the control unit 40 causes the LED element groups of any color to sequentially emit light within one frame time, and sequentially outputs only red light 71R, only blue light 71B, and only green light 71G. Or even three colors of L
It is also possible to simultaneously emit light from the ED element group and output white light 71W. Further, it is possible to sequentially output light of each color including the white light 71W. Therefore, it is possible to output from the projector 1 an image whose color has been adjusted according to the application such as a business scene or a cinema scene.

In this lighting device 10, the luminous flux 7 of each color supplied from the LED elements 14R to 14B of the lighting panel 12 is used.
1R to 71B are reflective inner peripheral surfaces 2 of the rod lens 20.
While being multiple-reflected at 1, the light is integrated inside the rod lens 20 so that the intensity distribution is evenly adjusted. The lighting device 10 further includes a cylindrical lens 48 arranged at the outlet 24 of the rod lens 20. Therefore, the light 7 output from the outlet 24 of the rod lens 20
Reference numeral 2 denotes the light valve 5 with the aspect ratio of the light valve 50 being enlarged or reduced in the vertical or horizontal direction by the cylindrical lens 48.
It is output toward 0. Therefore, by controlling the power of the cylindrical lens 48 and the distance to the light valve 50, the cross-sectional shape of the light 72R to 72B (including white) of each color output from the rod lens 20 at the position of the light valve 50 is written. The shape of the valve 50 can be matched. Therefore, the light 72 output from the rod lens 20 is not wasted and the light valve 50 is not wasted.
It is possible to irradiate the illuminating light to the illuminating device 10, and it is possible to provide the illuminating device 10 with high light utilization efficiency.

In the projector 1 of this example, a micromirror device having a switching direction is adopted as the light valve 50, and the switching direction S is set to the vertical direction. Therefore, the cylindrical lens 48 reduces the horizontal direction perpendicular to the switching direction S to adjust the aspect ratio. Lighting device 1
The light 72 of each color output from 0 has a large angular distribution in the horizontal direction with respect to the vertical direction, and conversely has a small angular distribution in the vertical direction. Therefore, since the angular distribution in the switching direction becomes small, it is easy to secure the resolution. In addition, the light 73 supplied from the illuminating device 10 and switched by the micromirror being inclined at a certain angle has a small angle distribution in the switching direction of the incident light 72, and thus the angle distribution of the reflected light 73 is small. Easy to swallow into the projection lens 52.

Therefore, contrary to the above, when adjusting the aspect ratio while expanding the outgoing light 72 by the cylindrical lens 48, it is desirable to expand in the switching direction S. On the other hand, in the case of an optical system in which the angular distribution in the switching direction S does not become small, F of the projection lens 52
It is desirable to increase the number so that it can be swallowed. However, separation from ineffective light is likely to be difficult.

This illuminating device 10 is a solid-state light source illuminating device which employs a rod lens 20 capable of making the light intensity uniform by multiple reflection of the inner surface 21 as an integrator. With the rod lens 20, basically, by guiding the light flux inside the rod lens 20, the rod lens 2
At the exit 24 of 0, a light beam whose intensity in the cross-sectional direction of the rod lens 20 is substantially uniform can be obtained. Therefore, when the solid-state light source is adopted, the LED is simply provided at the entrance 23 of the rod lens 20 without using an expensive optical element such as a lens array corresponding to each solid-state light-emitting element.
By simply arranging the elements 14R to 14B side by side, it is possible to obtain a light flux having a uniform aspect ratio and a desired aspect ratio from the exit 24 of the rod lens 20. Therefore, it is possible to provide a lighting device that uses a solid-state light source and that has a very simple structure and is inexpensive.

Further, in this example, the planar illumination panel 12 is provided at the entrance 23 of the rod lens 20 to provide a plurality of LEDs.
The elements 14R to 14B are arranged in a plane. Therefore, the luminous fluxes 71R to 71B output from the LED elements 14R to 14B are swallowed by the rod lens 20 without being absorbed by the adjacent LED elements, so that the light utilization efficiency is high. Further, since the illumination panel 12 is arranged in a state of being in close contact with the entrance 23 of the rod lens 20, light hardly leaks from the gap with the rod lens 20, and in this respect also, the light utilization efficiency is high.

When there are a plurality of LED elements of the same color, by arranging them in a plane at random,
This prevents the inner surface 21 of the rod lens 20 from being regularly multiple-reflected to generate a specific pattern in the light intensity distribution.

Since the lighting device 10 uses the LED elements 14R to 14B as the light source as described above,
It has all the advantages of a lighting device that uses a solid-state light source. For example, long life, quick response,
The advantage is that the running cost is low. Furthermore, as described above, the color balance can be adjusted and white light can be output by changing the time or timing of light emission of the LED elements 14R to 14B.
Further, it is possible to turn on the LED elements 14R to 14B at a high frequency so that color breakup is unlikely to occur, and by adopting the projector 1 it is possible to output a high quality image.

Further, since the rotary type color filter is unnecessary, the space therefor and the space for installing the motor are also unnecessary, and the device becomes compact. Further, in the illuminating device 10 of the present example, since color mixing is also performed by the rod lens 20, no expensive optical element such as a dichroic prism is required, and the optical path can be minimized.

Further, by making the aspect ratio of the cross section of the rod lens 20 similar to the aspect ratio of the light valve 50, the above-mentioned cylindrical lens 48 or similarly a toroidal lens having a large astigmatism is used. The light valve 50 without adjusting the aspect ratio of the light 72 output from the rod lens 20.
It is possible to adjust to

As shown in FIG. 3, in the illuminating device 11a, if the aspect ratio (vertical: horizontal) of the outer size of the light valve 50 is 3: 4, the cross section of the rod lens 20 and the outer size of the illuminating panel 12 are changed vertically. The size is 3x and the width is 4x. As a result, a light flux 72 having an aspect ratio of 3: 4 is output from the outlet 24, and the cross section of the light flux 72 expands in proportion to the distance while maintaining the aspect ratio. Therefore, by arranging the light valve 50 at an appropriate distance, the light emitted from the rod lens 20 can be applied to the light valve 50 without waste. Therefore, it is desirable that the cross section of the rod lens 20 is smaller than the light valve 50. In addition, the outlet 2 of the rod lens 20
It is also possible to arrange a lens 47 having an appropriate power in No. 4 to adjust the distance between the rod lens 20 and the light valve 50.

Further, in the above example, the LED elements 14R to 14B are arranged in a plane at the entrance 23 of the rod lens 20 so that the luminous fluxes output from them are guided to the rod lens 20 without leakage. Illumination device 11 shown in FIG.
In c, the elliptical reflector 16 is arranged at the entrance 23 of the rod lens 20, and the luminous flux 7 from the LED elements 14R to 14B is
1R to 71B are input to the rod lens 20 without omission. In particular, the end 16 on the exit side of the reflector 16
By integrating a so as to be connected to the incident side 23 of the rod lens 20, the reflector 16 and the rod lens 2 are integrated.
It is possible to prevent light from leaking through the gap with 0. Further, according to this method, a light flux that is multiple-reflected in the rod lens 20 and returns to the entrance side 23 is also reflected by the reflection panel 16 at the exit 2.
Reflect to the 4 side. Therefore, the light utilization efficiency can be further improved. Although the reflector 16 is not limited to an ellipse, the ellipse reflector is excellent in that it reflects light efficiently toward the rod lens 20.

Further, it is also effective to form a fine structure on the reflection surface 15a inside the reflection panel 16 to make it blaze, as in the illumination device 11d shown in FIG. The blazed reflecting surface 15a plays the role of a diffraction grating and can reduce the emission angle of the light beams 72R to 72B that pass through the rod lens 20 of the rod lens 20 and are emitted toward the light valve 50. It can be supplied to the valve 50. Therefore, the light utilization efficiency can be further improved.

In the above projector, an example in which a micromirror device is used for the light valve 50 has been described, but the present invention is not limited to this, and other types of light valves may be encountered, and light for extracting evanescent light may be encountered. It is also possible to use a switching device or a liquid crystal. Further, although an example in which an LED element is adopted as a light emitting source that constitutes the illumination panel 12 is described, the present invention is not limited to this, and other solid or semiconductor light emitting elements, solid state light emitting elements such as organic EL, solid state or semiconductor lasers are used. It is also possible.

[0033]

As described above, according to the present invention,
It is possible to realize an illuminating device using a solid-state light source with a simple structure in which a plurality of types of solid-state light-emitting elements are arranged at the entrance of a light guide path whose inner surface is a reflecting surface, and further, the strength is made uniform. Illumination light can be output. Therefore,
It is possible to provide a simple and low-cost lighting device that can take full advantage of solid-state light sources, such as easy adjustment of color balance.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a projector using an illumination device of the present invention.

FIG. 2 is a diagram showing an outline of the lighting device shown in FIG.

FIG. 3 is a diagram showing an outline of a lighting device different from the lighting device shown in FIG.

FIG. 4 is a diagram showing an outline of an illuminating device different from the illuminating device shown in FIG.

FIG. 5 is a diagram showing an outline of an illumination device further different from the illumination device shown in FIG.

[Explanation of symbols]

1 Projector 10, 11a, 11c, 11d Illumination device 12 Illumination panel 13 Supporting surface (flat surface) 14R, 14G, 14B LED element 20 of each color 20 Rod lens 21 Light guide path (inner peripheral surface) 22 Entrance 23 Exit 40 Control part 50 Light valve 52 Projection lens 55 Screens 71R, 71G, 71B Incident light of each color emitted from LED elements 72R, 72G, 72B Light flux of each color output from the rod lens (emitted light)

Claims (17)

[Claims] 1. A lighting device having a light guide path having a rectangular cross section and a reflective inner surface, and an illumination panel in which a plurality of types of solid-state light emitting elements for emitting light of different colors are arranged on the incident side of the light guide path. . 2. The lighting device according to claim 1, wherein the solid state light emitting elements are arranged in an array on the lighting panel so as to form a plane orthogonal to the light guide path. 3. The solid-state light-emitting element according to claim 2, wherein at least one type of solid-state light-emitting element includes a plurality of solid-state light-emitting elements, and the plurality of solid-state light-emitting elements includes the lighting panel. Lighting devices that are randomly arranged in the. 4. The illumination device according to claim 2, wherein the outer size of the lighting panel is the same as or similar to the outer size of a light valve that switches light beams emitted from the light guide path to form an image. 5. The illumination device according to claim 1, wherein a cross-sectional size of the light guide path is the same as or similar to an outer size of a light valve that switches light beams emitted from the light guide path to form an image. 6. The illumination device according to claim 1, wherein a cross-sectional size of the light guide path is smaller than a size of a light valve that modulates a light beam emitted from the light guide path to form an image. 7. The illumination device according to claim 1, further comprising a cylindrical lens or a toroidal lens that expands or contracts a light beam emitted from the light guide path in one direction. 8. The light valve according to claim 7, wherein the light valve is a mirror device, and the luminous flux emitted from the light guide path is greatly expanded or reduced in the switching direction of the light valve by the cylindrical lens or the toroidal lens. Lighting equipment. 9. The light valve according to claim 7, wherein the light valve is a mirror device, and the light flux emitted from the light guide path is enlarged by the cylindrical lens or the toroidal lens in a direction perpendicular to a switching direction of the light valve. Or, a lighting device that greatly reduces. 10. The illumination device according to claim 1, further comprising a reflective panel that is curved so as to guide the light flux from the illumination panel to the light guide path. 11. The lighting device according to claim 10, wherein an end of the reflection panel on the emission side is connected to an incidence side of the light guide path. 12. The lighting device according to claim 10, wherein the reflection panel is an elliptical reflector. 13. The lighting device according to claim 10, wherein a fine structure is formed on a reflection surface of the reflection panel. 14. The lighting device according to claim 1, wherein each of the plurality of types of solid state light emitting elements includes the number of the solid state light emitting elements based on the relative luminous efficiency. 15. The illumination device according to claim 1, wherein the plurality of types of solid-state light emitting elements have a control unit capable of emitting light by changing a timing and a time of irradiation for each type. 16. The control unit according to claim 15,
A lighting device capable of simultaneously emitting light from the plurality of types of solid-state light-emitting elements. 17. The lighting device according to claim 1, a light valve that modulates a light beam output from the lighting device to form an image, and a projection that projects light from the light valve. A projector having a lens.