JP2006285042A - Light source device and combined light source apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical apparatus capable of illuminating an illumination object by eliminating variations in light intensity caused by the emission angle of a light emitting element such as an LED. <P>SOLUTION: A rod integrator 4 is disposed so that the range in which a main quantity of light emitted from the light emitting element 2 overlaps the input end face of a rod integrator 4. Illuminating light entering the rod integrator 4 is propagated while totally reflected by the side face of the rod integrator 4. At this point, since the illuminating light is mixed within the rod integrator 4 and variations in intensity, caused by the incident angle of the light emitting element 2, are corrected, the illuminating light is made uniform in illuminance. The illuminating light whose illuminance is made uniform is emitted to a relay lens section 6 from the output end face of the rod integrator 4, then passed through a total reflection prism 8 and a reflection type display device 10, and used as image light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technology of a light source device suitable for use in an illumination system (system) such as a projector or a semiconductor exposure apparatus.

Since a projector requires a large amount of light, a high-intensity lamp such as an arc lamp is used as the light source. However, arc lamps (xenon lamps, halogen lamps, metal halide lamps, etc.) have short lifetimes. For example, with metal halide lamps, the center intensity of light is reduced by 50% in about 1000 hours of use.
For this reason, a long-life light source is required. The device described in Patent Document 1 describes a light source device using a light emitting diode. If a light emitting diode is used, the lifetime as a light source becomes remarkably long, which is preferable.
JP-A-11-32278

By the way, in the light source of patent document 1, the emitted light of each LED which comprises LED group is led to the irradiation target object with the lens or the mirror. In this case, the light of one LED is guided to a certain point to be irradiated, but considering the distribution of illuminance in the irradiation area that the LED is responsible for, the intensity of the emitted light from the LED varies depending on the emission angle. Even after passing through an optical path such as a mirror or a mirror, variations in intensity remain, and the illuminance varies even in the final irradiation area.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an optical device capable of irradiating an irradiation object without variation in light intensity due to an emission angle of a light emitting element such as an LED. .

In order to solve the above problems, the present invention has a columnar main body extending from an input end face toward an output end face, and when light enters the input end face, the light is reflected inside the main body and faces the output end face. A light source device comprising: an optical mixing member configured to mix and output light incident on the input end surface; and a light emitting element provided in the vicinity of the input end surface of the optical mixing member. To do.
Also, it has a columnar main body extending from the input end face toward the output end face, and is configured to be directed toward the output end face while being reflected inside the main body when light is incident on the input end face, and is incident on the input end face. A plurality of light-emitting units each paired with a light-mixing member that mixes and outputs the emitted light and a light-emitting element provided in the vicinity of the input end face, and each light-emitting unit is configured to bundle the light-mixing members. Provided is a light source device characterized by being assembled together.
In this case, it has a columnar main body extending from one end face toward the other end face, and is configured to face the other end face while being reflected inside the main body when light is incident on the one end face. A second optical mixing member that mixes and outputs the light incident on the one end surface; and the one end surface includes a plurality of light exiting from the output end surfaces of the bundled optical mixing members. Light may be incident.

Further, in the above configuration, the light emitting element is disposed in the vicinity of the optical mixing member such that a range in which a main light amount is emitted overlaps with the input end face, and a boundary line of the range is located at an edge of the input end face. Is preferred.
A plurality of the light emitting elements provided in the vicinity of the input end face may be provided.
When a plurality of light emitting elements are provided, the light emitting elements may be divided into a plurality of groups having different wavelengths of output light.
In addition, a plurality of light source devices described above can be provided, and a composite light source device having an optical system that guides output light of each light source device to the same object to be irradiated can also be configured.

  Since the output light of the light emitting elements is mixed by the mixing member, the illuminance distribution in the irradiation area assigned to each light emitting element is made uniform. Further, since each light emitting element is disposed in the vicinity of the input end face of the mixing member, most of the effective light output from the light emitting element is incident on the mixing member, and a lens or the like is interposed between the light emitting element and the mixing member. Since there is no optical system, the emitted light is incident on the mixing member with almost no attenuation.

Hereinafter, embodiments of the present invention will be described.
<First Embodiment>
FIG. 1 shows a configuration of a DLP (registered trademark) (Digital Light Processing) type projector using a DMD (registered trademark) (Digital Micromirror Device) having an illumination optical device 100 according to the first embodiment of the present invention. Yes. The illumination optical device 100 includes a pair of light emitting elements 2 such as LEDs and a rod integrator 4.

  The rod integrator 4 is a rectangular parallelepiped transparent light guide, and is fixed in a state where the central axis thereof coincides with the optical axes of the light emitting element 2 and the relay lens unit 6. Here, the illumination light from the light emitting element 2 is incident on one end face of the rod integrator 4 (hereinafter referred to as the input end face 4 a), propagates while being totally reflected by the side face of the rod integrator 4, and the other end of the rod integrator 4. The light is emitted from the end face (hereinafter referred to as the output end face 4b) toward the relay lens unit 6.

  The light emitting element 2 is provided close to the input end face 4 a of the rod integrator 4. For example, as shown in FIG. 2, a range in which the main light amount of the light emitting element 2 is emitted overlaps the input end face 4a, and a boundary line L1 of the range is positioned at the edge of the input end face 4a. To. In this case, an optical system such as a lens is not provided between the light emitting element 2 and the input end face 4a, and the range for emitting the main light amount substantially overlaps the input end face 4a as described above. Most of the output light from the light emitting element 2 enters the rod integrator 4 without being attenuated.

  Light emitted from the rod integrator 4 passes through the relay lens unit 6 and becomes parallel light. The total reflection prism 8 totally reflects the illumination light that has passed through the relay lens unit 6 and enters the reflection type display device 10.

  FIG. 3A is a diagram showing the configuration of the reflective display device 10. The reflective display device 10 performs spatial modulation on the illumination light from the total reflection prism 8 for each pixel, and is configured by arranging a plurality of square micromirrors 101 of about 13 μm in a two-dimensional array. Yes.

  FIG. 3B is a diagram illustrating the operation of the micromirror 101. The micromirror 101 is supported by a pivot 105 on the semiconductor substrate 103 of the reflective display device 10. Each micromirror 101 deflects based on an electrostatic force generated when a transistor (not shown) formed on the array of the semiconductor substrate 103 is turned on, and illuminates light from the light emitting element 2 as effective reflected light (irradiates outside) 3), the micromirror 101 is brought into a state indicated by a solid line in FIG. 3B, and the illumination light is sequentially reflected toward the projection lens 12. On the other hand, in the case of invalid reflected light (light that is not irradiated to the outside), the micromirror 101 is placed in a state indicated by a broken line in FIG. 3B so that the illumination light is absorbed by the stopper 102. The micromirror 101 controls the reflection time to the projection lens 12 according to the magnitude of the pixel signal. For example, if the pixel signal is 8 bits, the amount of reflected light changes in 256 gradations. That is, the gradation for each pixel is expressed by controlling the reflection time of each micromirror 101.

  The illumination light reflected by the reflective display device 10 passes through the total reflection prism 8. The projection lens 12 projects the light reflected by the reflective display device 10 and transmitted through the total reflection prism 8 onto a screen (not shown).

According to the embodiment described above, the life of the light source can be extended by using the LED as the light source. Further, since the output light of the light emitting element 2 is mixed by the rod integrator 4, the illuminance on the surface of the two-dimensional matrix of the micromirror 101 of the reflective display device 10 to be irradiated becomes uniform. That is, the light emitting element 2 such as an LED has a light intensity characteristic as shown in FIG. Here, FIG. 4 is a diagram illustrating an example of a light distribution of illumination light emitted from the light emitting element 2. A general LED light distribution may be as shown in FIG. 4, and in this case, there is a problem that the light utilization efficiency deteriorates when only the output light at the center is used. Therefore, if the light emitted from the light emitting element 2 is guided as it is and the irradiation target is irradiated, the irradiation area that the light emitting element is responsible for varies due to the light intensity characteristics shown in FIG. In this embodiment, since the rod integrator 4 is used, the intensity variation due to the emission angle of the light emitting element is corrected and made uniform by the mixing effect due to the reflection of light in the rod integrator 4. Further, since the light emitting element 2 is disposed in the vicinity of the input end face 4a, most of the light output from the light emitting element 2 is incident on the rod integrator 4 without being attenuated. There is an effect that can take a lot.

  In the above-described embodiment, the solid rod integrator 4 is used. However, as shown in FIG. 5A, a hollow rod integrator 4 'may be used. The hollow rod integrator 4 'has a mirror on the inner surface, and the incident light is reflected by the inner mirror. The hollow rod integrator 4 'performs the same operation as that of the solid rod integrator 4 described above. However, in the case of the hollow rod integrator 4', as shown in FIG. It can be configured to be located inside the rod integrator 4 '.

Second Embodiment
FIG. 6 is a diagram showing a configuration of an illumination optical apparatus according to the second embodiment of the present invention. In the said 1st Embodiment, although the example using a pair of light emitting element 2 and the rod integrator 4 was shown, in this embodiment, this pair is provided with two or more. In the present embodiment, a hollow rod integrator 4 'is used.

  Here, an enlarged side view of the light emitting element 2 and the rod integrator 4 'is shown in FIG. As shown in this figure, in the present embodiment, the light emitting point of the light emitting element 2 is located in the rod integrator 4 '. Further, since the figure is a side view, each of the four light emitting elements 2 and the rod integrator 4 ′ is shown, but when viewed from the front, it is a 4 × 4 matrix.

Here, a perspective view of the rod integrators 4 ′, 4 ′,... Is shown in FIG. As shown in this figure, the rod integrators 4 ', 4',... Are bundled so as to form a 4 × 4 matrix when viewed from the front.
As shown in FIG. 8B, it is conceivable to use one rod integrator 40 having a large end surface area, but in this case, the number of times of light reflection inside the rod integrator 40 is reduced. In order to obtain the same effect as that shown in FIG. 8A, the length in the longitudinal direction of the rod integrator 40 must be increased, which causes problems such as an increase in the size of the apparatus.

  In the present embodiment, since the elongated rod integrator 4 ′ having a small end surface area is used in a bundle, the above-described problem does not occur. Furthermore, since the pair of the light emitting element 2 and the rod integrator 4 'are bundled in a matrix, there is an advantage that the amount of light output from the aggregate of the rod integrator 4' is increased.

Since the rod integrator 4 'is assembled, the boundary between them may be reflected in the illumination target.
Therefore, a rod integrator 42 may be further provided to cover each tip portion of the bundled rod integrator 4 '. FIG. 9 shows a side view of the rod integrator 4 ′ and the rod integrator 42 at this time. The rod integrator 42 has a rectangular parallelepiped hollow body, and the inner surface of the body is a mirror.

According to the above configuration, since the emitted light from the set of rod integrators 4 ′ is mixed by the rod integrator 42, the irradiation light with the boundary between the aggregates of the rod integrator 4 ′ disappearing is incident on the reflective display device 10. Will be.
Of course, a solid rod integrator may be used in this embodiment.

<Third Embodiment>
FIG. 10 is a diagram showing a configuration of an illumination optical apparatus according to the third embodiment of the present invention. In this embodiment, three light source units shown in the second embodiment are provided, and green, red, and blue LEDs are used as the respective light emitting elements. In FIG. 10, a unit using a green LED is shown as a unit U1, a unit using a red LED is shown as a unit U2, and a unit using a blue LED is shown as a unit U3.
In addition, relay lenses 6a, 6b, 6c and a cross dichroic prism 14 for guiding the emitted light of each unit U1 to U3 to the reflective display device 10 to be irradiated are provided.

  The illumination light emitted from the units U1 to U3 is converted into parallel light by the relay lenses 6a to 6c and emitted to the cross dichroic prism 14. The illumination light from the unit U 1 that has entered the cross dichroic prism 14 passes through the cross dichroic prism 14 and is emitted to the total reflection prism 8. The illumination light from the unit U2 is emitted by the cross dichroic prism 14 to the total reflection prism 8 with the optical path bent by 90 degrees. Similarly, the illumination light from the unit U3 is emitted by the cross dichroic prism 14 to the total reflection prism 8 after the optical path is bent by 90 degrees.

  As described above, the green, red, and blue illumination lights incident from the respective units are sequentially emitted, and the reflective display device 10 generates an image of the color at the timing when each color is emitted. As a result, a color image is generated.

<Other embodiments>
In each of the above-described embodiments, the illumination optical device has been described by way of example when applied to a DLP projector using DMD. However, in addition to the DLP system, there are various projectors such as an LCOS (Liquid Crystal On Silicon) system projector and a transmissive LCD projector. The illumination device according to the present invention can be applied to various projectors regardless of the display element or the optical system by making necessary modifications according to the system of the projector.

  Moreover, although the case where one rod integrator was provided in one light emitting element was shown in the said embodiment, the number of the light emitting elements with respect to a rod integrator is not restricted to one, A plurality may be sufficient. An example is shown in FIG. FIG. 11 shows a case where two light emitting elements 2 are provided for one rod integrator 4 ′.

  The color of the light emitting element is not limited to a single color, and a plurality of colors of LEDs may be provided as the light emitting element 2 as shown in FIG. In FIG. 12, “R”, “B”, and “G” indicate red, blue, and green LEDs, respectively. Furthermore, the number of LEDs is not limited to the 3 × 3 number shown in the above-described embodiment and FIG. 12, and a larger number (m × n) may be provided.

It is a figure which shows the structure of the projector which has the illumination optical apparatus which is 1st Embodiment of this invention. It is an example of arrangement | positioning of the light emitting element and rod integrator which concern on the same embodiment. FIG. 44E is an explanatory diagram of the reflective display device according to the embodiment. It is a figure which shows the light intensity distribution of the light emitting element which concerns on the same embodiment. It is a figure which shows the structure of the rod integrator which concerns on the same embodiment. It is a figure which shows the structure of the projector which has the illumination optical apparatus which is 2nd Embodiment of this invention. It is a side view of the light emitting element and rod integrator concerning the embodiment. It is a perspective view of the rod integrator concerning the embodiment. It is a figure which shows the structure of the rod integrator which concerns on the same embodiment. It is a figure which shows the structure of the projector which has the illumination optical apparatus which is 3rd Embodiment of this invention. It is the example of arrangement | positioning of the light emitting element and rod integrator in other embodiment. It is a figure which shows the structural example of the light emitting element in the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Light emitting element, 4, 4 ', 40 ... Rod integrator, 6 ... Relay lens part, 8 ... Total reflection prism, 10 ... Reflective display device, 12 ... Projection lens, 14 ... Cross dichroic prism, 100 ... Illumination optical apparatus

Claims (7)

It has a columnar body extending from the input end face toward the output end face. When light is incident on the input end face, the light is incident on the input end face while being reflected inside the body. An optical mixing member that mixes and outputs light; and
A light emitting device provided in the vicinity of an input end face of the optical mixing member. It has a columnar body extending from the input end face toward the output end face. When light is incident on the input end face, the light is incident on the input end face while being reflected inside the body. A plurality of light emitting units in which a light mixing member that mixes and outputs light and a light emitting element provided in the vicinity of the input end surface are paired,
Each of the light emitting units is configured to be assembled so that the light mixing members are bundled together.   A columnar main body extending from one end face toward the other end face, and configured to be directed toward the other end face while being reflected inside the main body when light is incident on the one end face; A second optical mixing member that mixes and outputs the light incident on the end surface, and a plurality of light beams emitted from the output end surfaces of the bundled optical mixing members are incident on the one end surface; The light source device according to claim 2, wherein:   The light emitting element is disposed in the vicinity of the optical mixing member so that a range in which a main light amount is emitted overlaps with the input end face, and a boundary line of the range is located at an edge of the input end face. The light source device according to claim 1.   5. The light source device according to claim 1, wherein a plurality of the light emitting elements are provided in the vicinity of the input end face.   4. The light source device according to claim 2, wherein each of the light emitting elements is divided into a plurality of groups having different wavelengths of output light.   A compound light source device comprising a plurality of light source devices according to claim 2 and an optical system for guiding output light of each light source device to the same irradiation object.

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