JP2015191004A - Light source device and image projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device that can accurately detect the output state of a plurality of light sources, and an image projection device.SOLUTION: A light source device 2 includes: a plurality of light sources 11 that emit laser beams; an optical member 21 that transmits or reflects a part of the light emitted from the plurality of light sources 11; an optical system 22 on which the light transmitted or reflected by the optical member 21 is made incident; and a light detection part 23 that detects the light emitted from the optical system 22, where the optical system 22 includes at least one of an integrator optical system 22b that makes the intensities of rays of light made incident thereon uniform and emits the light and a diffusion optical system that diffuses light made incident thereon and emits the light.

Description

  The present invention relates to a light source device including a plurality of light sources that emit laser light and a light detection unit that detects light. The present invention also relates to an image projection apparatus including a light source device.

  Conventionally, as a light source device, a light source device including a light source that emits laser light and a light detection unit that detects light is known (for example, Patent Document 1). According to such a light source device, since the light detection unit can detect a part of the laser light emitted from the light source, the output state of the light source can be detected.

  By the way, in the light source device according to Patent Document 1, the light detection unit is disposed on the optical path of the laser light emitted from the light source, and laser light other than the laser light of the backbone system (system actually used as the device). Therefore, the arrangement of the light detection unit cannot be flexibly handled. Therefore, in a light source device having a plurality of light sources, only the output state of a specific light source such as one or two can be detected, and thus the output state of the entire light source cannot be detected accurately.

JP 2003-228868 A

  Therefore, in view of such circumstances, an object of the present invention is to provide a light source device and an image projection device that can accurately detect output states of a plurality of light sources.

  The light source device according to the present invention includes a plurality of light sources that emit laser light, an optical member that transmits or reflects a part of the light emitted from the plurality of light sources, and light that is transmitted or reflected by the optical member. An incident optical system; and a light detection unit that detects light emitted from the optical system, the optical system including an integrator optical system that emits light with uniform light intensity of incident light and an incident light And at least one of a diffusion optical system that diffuses and emits the emitted light.

  According to the light source device of the present invention, the optical member transmits or reflects a part of the laser light emitted from the light source. The optical system receives light transmitted or reflected by the optical member. Thereafter, the light detection unit detects light emitted from the optical system.

  The optical system includes an integrator optical system (or / and a diffusing optical system that diffuses and emits incident light) that emits light with uniform intensity of incident light. Not only the light emitted from the light source but also the light emitted from a plurality of light sources can be comprehensively detected. Therefore, it is possible to accurately detect output states of a plurality of light sources.

In the light source device according to the present invention, the light emitted from the plurality of light sources is emitted from the second surface toward the optical member by making the light parallel to the first surface. A collimator optical system, and the optical member is arranged so that the reflected light reflected by the optical member is incident on the second surface of the collimator optical system, and the optical system includes the reflected light Arranged so as to be emitted from the first surface of the collimator optical system toward the optical system,
It may be configured as follows.

  According to such a configuration, the divergent light emitted from the plurality of light sources is incident on the first surface of the collimator optical system, and the light emitted from the second surface of the collimator optical system is converted into parallel light, which is optical. Head to the member. Since the optical member is disposed at a predetermined position, the reflected light reflected by the optical member enters the second surface of the collimator optical system. At this time, since the optical member reflects parallel light, the reflected light incident on the second surface of the collimator optical system is parallel light.

  And since the optical system is arrange | positioned in the predetermined position, the said reflected light radiate | emits toward the optical system from the 1st surface of a collimator optical system. At this time, since the reflected light incident on the second surface of the collimator optical system is parallel light, the light emitted from the first surface of the collimator optical system becomes convergent light. Accordingly, the collimator optical system has not only a function of collimating the diverging light emitted from the light source and emitting it to the optical member, but also a function of converging the parallel light reflected by the optical member and emitting it to the optical system.

  Moreover, in the light source device according to the present invention, the optical system includes an incident part on which the reflected light emitted from the first surface of the collimator optical system is incident, and the incident part is an element of the collimator optical system. It may be arranged at the condensing position of the reflected light emitted from the first surface.

  According to such a configuration, the incident part of the optical system into which the reflected light emitted from the first surface of the collimator optical system is incident is disposed at the condensing position of the reflected light. Thereby, since the light detection part can detect the light radiate | emitted from the several light source more comprehensively, it can detect the output state of a several light source more correctly.

  Moreover, in the light source device according to the present invention, the optical member includes a planar incident surface on which light is incident so as to reflect a part of the light emitted from the light source, and is formed only of optical glass. The optical system may be arranged so that the reflected light reflected by the optical member is incident thereon.

  According to such a configuration, when light emitted from the light source is incident on the incident surface of the optical member, a part of the light is reflected on the incident surface of the optical member. Further, since the optical system is disposed at a predetermined position, the reflected light reflected by the optical member is incident on the optical system.

  Since the optical member is formed only of optical glass and the incident surface of the optical member is formed in a flat shape, an error in reflectance due to the wavelength of light (ripple in the reflectance graph with respect to the wavelength of light) is suppressed. be able to. Therefore, even if the wavelengths of the laser beams emitted from the plurality of light sources change with changes in usage conditions, environmental conditions, etc., the output states of the plurality of light sources can be accurately detected.

  In addition, the image projection apparatus according to the present invention includes at least one of the light source devices, and one of the lights transmitted and reflected by the optical member is detected by the light detection unit, and the other is projected light. Used.

  As described above, the present invention has an excellent effect that the output states of a plurality of light sources can be accurately detected.

1 is an overall schematic diagram of an image projection apparatus according to an embodiment of the present invention. It is the principal part schematic diagram of the light source device which concerns on the same embodiment, Comprising: It is the figure which showed the condition of the core system light. It is the principal part schematic diagram of the light source device which concerns on the same embodiment, Comprising: It is the figure which showed the condition of the detection light. It is the figure which showed the relationship of the reflectance with respect to the incident angle in the optical member which concerns on the embodiment. It is a whole schematic diagram of the image projector which concerns on other embodiment of this invention. It is a principal part schematic diagram of the light source device which concerns on the embodiment. It is a principal part schematic diagram of the light source device which concerns on further another embodiment of this invention.

<First Embodiment>
Hereinafter, a first embodiment of a light source device and an image projection device according to the present invention will be described with reference to FIGS. In each figure (the same applies to FIGS. 5 to 7), the dimensional ratio in the drawing does not necessarily match the actual dimensional ratio.

  As shown in FIG. 1, the image projection apparatus 1 according to the present embodiment includes a plurality (three in the present embodiment) of light source devices 2 (2R, 2G, and 2B) that emit light of different colors. Yes. Further, the image projection device 1 receives the laser light emitted from the light source device 2 and generates an optical image, and the light image emitted from the image optical system 60 is incident and projected onto the screen 80. Projection optical system (for example, projection lens) 70.

  The first light source device 2R emits light of a first color (for example, red), the second light source device 2G emits light of a second color (for example, green), and a third light source The device 2B emits light of a third color (for example, blue). That is, the plurality of light source devices 2R, 2G, and 2B emit light having different wavelengths.

  The image optical system 60 includes a spatial modulation element 60a that converts the light emitted from the light source device 2 into an optical image, a total reflection prism 60b, and a dichroic prism 60c. In addition, the image optical system 60 includes a reflection mirror 60d that reflects the laser light emitted from the second light source device 2G. In the present embodiment, each spatial modulation element 60a is a digital micromirror device. The image optical system 60 may include a spatial modulation element 60a that is a transmissive or reflective liquid crystal element.

  As shown in FIG. 2, the light source device 2 includes a plurality (five in FIG. 2) of light sources 11 that emit laser light, and a plurality (five in FIG. 2) to which the laser light emitted from each light source 11 is incident. ) Optical fiber 12. The light source device 2 also includes a collimator optical system 13 into which the light emitted from the optical fiber 12 is incident, an optical member 21 that reflects a part of the light emitted from the collimator optical system 13, and the optical member 21. The converging lens 14 into which the incident light is incident is provided.

  The light source device 2 includes a rod integrator 15 into which light emitted from the converging lens 14 is incident, and an imaging lens 16 into which light emitted from the rod integrator 15 is incident. Further, the light source device 2 includes an optical system 22 into which light reflected by the optical member 21 is incident, and a light detection unit 23 that detects light emitted from the optical system 22. In FIG. 2, a one-dot chain line indicates light from the light source 11 to the optical member 21, and a two-dot chain line indicates light transmitted through the optical member 21.

  Although not shown, each light source 11 includes at least one semiconductor laser that emits laser light. Moreover, each light source 11 may be provided with the lens for making the laser beam radiate | emitted from the semiconductor laser efficiently inject into the optical fiber 12 as needed.

  The plurality of optical fibers 12 are arranged so that their emission surfaces are flush with each other. That is, the emission surfaces of the plurality of optical fibers 12 are arranged on the same plane. For example, the emission surface side of the plurality of optical fibers 12 has a so-called bundle structure that is held by a holding member (not shown) in a bundled state.

  The collimator optical system 13 includes a collimator lens. Light that is emitted from the plurality of light sources 11 and diverges through the optical fiber 12 is incident on the first surface 13a of the collimator optical system 13, and the collimator optical system 13 converts the light into parallel light and converts it into an optical member 21. It radiates | emits from the 2nd surface 13b toward.

  The converging lens 14 converges the light transmitted through the optical member 21 and emits the light toward the rod integrator 15. The collimator optical system 13 and the converging lens 14 form an image of the exit surface of the optical fiber 12 on the entrance surface of the rod integrator 15.

  The rod integrator 15 emits light with uniform intensity of incident light so that the illuminance on the exit surface is uniform. The imaging lens 16 forms an image of the exit surface of the rod integrator 15 on the incident surface of the spatial modulation element 60 a of the image optical system 60.

  As shown in FIG. 3, the optical member 21 includes a planar incident surface 21 a on which light emitted from the second surface 13 b of the collimator optical system 13 is incident. The optical member 21 is formed in a flat plate shape. The optical member 21 is arranged so that the reflected light reflected by the optical member 21 enters the second surface 13 b of the collimator optical system 13.

  In the present embodiment, the optical member 21 is formed of only optical glass. The optical member 21 is provided with a dielectric multilayer film (reflection suppression coating) on an incident surface (or / and an output surface) of a flat optical glass, and reflects (or transmits) part of incident light. The structure of being a member to be used may be used.

  The optical system 22 includes an incident portion 22a where the reflected light emitted from the first surface 13a of the collimator optical system 13 is incident, and an integrator optical system 22b where the reflected light emitted from the incident portion 22a is incident. Yes. In the present embodiment, the incident portion 22a is a reflecting member that reflects incident reflected light toward the integrator optical system 22b.

  In FIG. 3, a one-dot chain line indicates light from the light source 11 to the optical member 21, a two-dot chain line indicates light transmitted through the optical member 21, and a broken line indicates light reflected by the optical member 21. Yes. The parallel reflected light reflected by the optical member 21 is incident on the second surface 13b of the collimator optical system 13, and the collimator optical system 13 converges and emits the reflected light from the first surface 13a.

  The optical system 22 is arranged so that the reflected light emitted from the first surface 13 a of the collimator optical system 13 is directed to the optical system 22. Specifically, the incident portion 22 a of the optical system 22 is disposed at a condensing position of reflected light emitted from the first surface 13 a of the collimator optical system 13.

  The integrator optical system 22 b equalizes the light intensity of the incident light and emits it toward the light detection unit 23. In the present embodiment, the integrator optical system 22b is composed of a rod integrator. The integrator optical system 22b may be composed of a fly eye lens, or may be composed of both a rod integrator and a fly eye lens.

  The light detection unit 23 is an optical sensor that measures the amount of light. In the present embodiment, the light detection unit 23 receives a part of the light emitted from the optical system 22 (integrator optical system 22b) and measures the amount of light. The light detection unit 23 may receive all of the light emitted from the optical system 22 and measure the light amount.

  In this way, the light transmitted through the optical member 21 is emitted from the light source device 2 and used as projection light (basic light) of the image projection device 1. The light reflected by the optical member 21 is detected by the light detection unit 23 and used as detection light for detecting the output states of the plurality of light sources 11. Then, the control unit 90 controls the output of the light source 11 based on the amount of light detected by the light detection unit 23, for example, with power (current, voltage) supplied to the light source 11.

  Here, the material of the optical member 21 will be described.

  In the reflectance of the optical member 21, there may be an error due to the wavelength of light (ripple in the graph of the reflectance with respect to the wavelength of light). For example, in an optical member in which a dielectric multilayer film (reflection suppressing coating) is applied to the incident surface of a flat optical glass, generally, the reflectance (for example, 0.5%) serving as a reference is There is an error of ± 0.05 to 0.15% (10% to 30% of the reference reflectance) depending on the wavelength of light.

  On the other hand, in the optical member 21 formed only of the flat optical glass, there is no error due to the wavelength of light with respect to the reference reflectance (for example, 4%). Therefore, the structure that the optical member 21 is formed only with optical glass is preferable.

  Further, the optical member 21 is disposed so that the incident surface 21a is inclined and intersects the optical axis L1 of the light emitted from the collimator optical system 13. Therefore, the incident angle θ1 at which the light emitted from the collimator optical system 13 enters the optical member 21 will be described with reference to FIG.

  As shown in FIG. 4, as the incident angle of light with respect to the optical member 21 is different, the reflectance at the incident surface 21 a of the optical member 21 is also different. The graph of FIG. 4 is obtained by calculating the reflectance of light incident on the optical member 21 of optical glass (refractive index: 1.5) from air (refractive index: 1) from the Fresnel equation. In FIG. 4, a solid line R1 indicates the case of P-polarized light, and a broken line R2 indicates the case of S-polarized light.

  For example, when light is incident on the optical member 21 at an incident angle of 45 °, most of the reflected light becomes S-polarized light. Then, the closer the incident angle is to 0 degrees (that is, the angle incident perpendicularly to the optical member 21), the smaller the difference in reflectance due to polarized light. Specifically, if the incident angle is 10 ° or less, the difference in reflectance due to polarized light is 20% or less, and if the incident angle is 5 ° or less, the difference in reflectance due to polarized light is almost eliminated.

  Therefore, the incident angle θ1 at which the light (optical axis L1) emitted from the collimator optical system 13 enters the optical member 21 is preferably 10 ° or less. The incident angle θ1 at which the light (optical axis L1) emitted from the collimator optical system 13 enters the optical member 21 is more preferably 5 ° or less.

  As described above, according to the light source device 2 according to the present embodiment, the optical member 21 reflects a part of the laser light emitted from the light source 11. Then, the light reflected by the optical member 21 enters the optical system 22. Thereafter, the light detection unit 23 detects a part of the light emitted from the optical system 22.

  Since the optical system 22 includes the integrator optical system 22b that uniformizes and emits the light intensity of incident light, the light detection unit 23 receives not only light emitted from the specific light source 11 but also a plurality of light sources 11. The emitted light can be comprehensively detected. Therefore, the output states of the plurality of light sources 11 can be accurately detected.

  Further, according to the light source device 2 according to the present embodiment, divergent light emitted from the plurality of light sources 11 is incident on the first surface 13a of the collimator optical system 13 via the optical fiber 12, and the collimator optical system. The light emitted from the second surface 13 b of the thirteenth light becomes parallel light and travels toward the optical member 21. Since the optical member 21 is disposed at a predetermined position, the reflected light reflected by the optical member 21 enters the second surface 13 b of the collimator optical system 13. At this time, since the optical member 21 reflects the parallel light, the reflected light incident on the second surface 13b of the collimator optical system 13 is parallel light.

  Since the optical system 22 is disposed at a predetermined position, the reflected light is emitted from the first surface 13 a of the collimator optical system 13 toward the optical system 22. At this time, since the reflected light incident on the second surface 13b of the collimator optical system 13 is parallel light, the light emitted from the first surface 13a of the collimator optical system 13 becomes convergent light. Thereby, the collimator optical system 13 not only has a function of collimating the light emitted from the light source 11 and emitting it to the optical member 21, but also a function of converging the light reflected by the optical member 21 and emitting it to the optical system 22. Have both.

  Further, according to the light source device 2 according to the present embodiment, the incident portion 22a of the optical system 22 on which the reflected light emitted from the first surface 13a of the collimator optical system 13 is incident is at the condensing position of the reflected light. Has been placed. Thereby, since the light detection part 23 can detect the light radiate | emitted from the several light source 11 more comprehensively, it can detect the output state of the several light source 11 more correctly.

  Further, according to the light source device 2 according to the present embodiment, when light emitted from the light source 11 is incident on the incident surface 21 a of the optical member 21, a part of the light is reflected on the incident surface 21 a of the optical member 21. Is done. Further, since the optical system 22 is disposed at a predetermined position, the reflected light reflected by the optical member 21 enters the optical system 22.

  Since the optical member 21 is formed only of optical glass and the incident surface 21a of the optical member 21 is formed in a flat shape, the reflectance error due to the wavelength of light (ripple in the reflectance graph with respect to the wavelength of light). Can be suppressed. Therefore, even if the wavelengths of the laser beams emitted from the plurality of light sources 11 change with changes in usage conditions, environmental conditions, etc., the output states of the plurality of light sources 11 can be accurately detected.

Second Embodiment
Next, a second embodiment of the light source device and the image projection device according to the present invention will be described with reference to FIGS. 5 and 6, the parts denoted by the same reference numerals as those in FIGS. 1 to 4 represent the same configurations or elements as those in the first embodiment, and the description thereof will not be repeated.

  As shown in FIG. 5, the image projection apparatus 1 according to the present embodiment includes a light source device 2 that emits light of different colors (for example, red, green, and blue) repeatedly in order. Further, the image projection apparatus 1 includes an image optical system 60 and a projection optical system 70.

  In the present embodiment, the spatial modulation element 60 a forms an image of each color by synchronizing with the light source device 2. Note that the image optical system 60 may be configured such that the light is color-separated and an image of each color is formed by the plurality of spatial modulation elements 60a, and then color synthesis is performed again. In such a configuration, the light source device 2 may emit light of different colors at the same time.

  As shown in FIG. 6, the light source device 2 includes a plurality of light sources 11, a plurality of optical fibers 12, a collimator optical system 13, an optical member 21, an optical system 22, and light detection for each color (wavelength). Part 23. A configuration including the light source 11, the optical fiber 12, the collimator optical system 13, the optical member 21, and the optical system 22 is referred to as a light source unit 10.

  A plurality (three in the present embodiment) of the light source units 10 emit light of different colors (wavelengths). The first light source unit 10R emits light of a first color (for example, red), the second light source unit 10G emits light of a second color (for example, green), and a third light source The unit 10B emits light of a third color (for example, blue).

  The light source device 2 includes a converging lens 14, a rod integrator 15, and an imaging lens 16. Further, the light source device 2 includes a combining optical system 17 that combines the light emitted from the plurality of light source units 10 and enters the converging lens 14. The combining optical system 17 includes a reflecting mirror 17a and a dichroic mirror 17b.

  As described above, according to the light source device 2 according to the present embodiment, the converging lens 14, the rod integrator 15, and the imaging lens 16 are made common to the plurality of light source units 10. Therefore, the apparatus can be simplified.

  In addition, this invention is not limited to the structure of above-described embodiment, Moreover, it is not limited to an above-described effect. In addition, the present invention can be variously modified without departing from the gist of the present invention. For example, the configurations and methods of the plurality of embodiments described above may be arbitrarily adopted and combined (the configurations and methods according to one embodiment may be combined with the configurations and methods according to the other embodiments). Further, it is of course possible to arbitrarily select configurations, methods, and the like according to various modifications described below and adopt them in the configurations, methods, and the like according to the above-described embodiments.

  In the light source device 2 according to the above embodiment, the optical system 22 is configured such that light reflected by the optical member 21 is incident, and the light detection unit 23 detects light emitted from the optical system 22. . However, the light source device according to the present invention is not limited to such a configuration. For example, in the light source device according to the present invention, as shown in FIG. 7, the optical system 22 receives light that passes through the optical member 21, and the light detection unit 23 detects light emitted from the optical system 22. It may be configured to do.

  According to such a configuration, light transmitted through the optical member 21 (indicated by a two-dot chain line in FIG. 7) is detected by the light detection unit 23 and used as detection light for detecting the output states of the plurality of light sources 11. It is done. In the configuration according to FIG. 7, the light reflected by the optical member 21 (shown by a broken line in FIG. 7) is emitted from the light source device 2 and used as the projection light of the image projection device 1.

  In the light source device 2 according to the above embodiment, the light reflected by the optical member 21 is incident on the optical system 22 via the collimator optical system 13. However, the light source device according to the present invention is not limited to such a configuration. For example, the light source device according to the present invention may be configured such that the light reflected by the optical member 21 is directly incident on the optical system 22.

  Moreover, in the light source device 2 according to the above-described embodiment, the optical system 22 includes the integrator optical system 22b. However, the light source device according to the present invention is not limited to such a configuration. For example, in the light source device according to the present invention, the optical system may include a diffusion optical system that diffuses and emits incident light, and includes both the integrator optical system 22b and the diffusion optical system. The structure of, may be used. The diffusion optical system is composed of a diffusion plate.

  In the light source device 2 according to the above-described embodiment, the collimator optical system 13 is configured by one collimator lens. However, the light source device according to the present invention is not limited to such a configuration. For example, in the light source device according to the present invention, the collimator optical system may include a plurality of lenses.

  In such a collimator optical system, the first surface that receives the light emitted from the plurality of light sources 11 and emits the reflected light reflected by the optical member 21 toward the optical system 22 is provided in a predetermined lens. The second surface on which the reflected light that is emitted from the light source 11 toward the optical member 21 and reflected by the optical member 21 is incident is provided in another lens.

  Moreover, in the light source device 2 which concerns on the said embodiment, it is the structure that the optical member 21 is formed in flat form. However, the light source device according to the present invention is not limited to such a configuration. For example, in the light source device according to the present invention, the optical member 21 is also used as the collimator optical system 13 or the converging lens 14, that is, the light reflected by the incident surface of the collimator optical system 13 or the converging lens 14 is optical. It may be configured to be incident on the system 22.

  DESCRIPTION OF SYMBOLS 1 ... Image projector, 2 ... Light source device, 2R ... 1st light source device, 2G ... 2nd light source device, 2B ... 3rd light source device, 10 ... Light source part, 10R ... 1st light source part, 10G ... 2nd light source part, 10B ... 3rd light source part, 11 ... Light source, 12 ... Optical fiber, 13 ... Collimator optical system, 13a ... 1st surface, 13b ... 2nd surface, 14 ... Converging lens, 15 ... Rod integrator , 16 ... Imaging lens, 17 ... Synthetic optical system, 17a ... Reflecting mirror, 17b ... Dichroic mirror, 21 ... Optical member, 21a ... Incident surface, 22 ... Optical system, 22a ... Incident part, 22b ... Integrator optical system, 23 DESCRIPTION OF SYMBOLS ... Photodetection part 60 ... Image optical system, 60a ... Spatial modulation element, 60b ... Total reflection prism, 60c ... Dichroic prism, 60d ... Reflection mirror, 70 ... Projection optical system, 80 ... Screen, 90 ... Control , L1 ... optical axis, .theta.1 ... incident angle

Claims (5)

A plurality of light sources for emitting laser light;
An optical member that transmits or reflects part of the light emitted from the plurality of light sources;
An optical system on which light transmitted or reflected by the optical member is incident;
A light detection unit for detecting light emitted from the optical system,
The optical system is a light source device including at least one of an integrator optical system that emits light with uniform light intensity of incident light and a diffusion optical system that diffuses and emits incident light. A collimator optical system that radiates and emits light from the plurality of light sources is incident on the first surface, converts the light into parallel light, and exits from the second surface toward the optical member;
The optical member is arranged so that the reflected light reflected by the optical member is incident on the second surface of the collimator optical system,
The light source device according to claim 1, wherein the optical system is arranged so that the reflected light is emitted from the first surface of the collimator optical system toward the optical system. The optical system includes an incident portion on which reflected light emitted from the first surface of the collimator optical system is incident.
The light source device according to claim 2, wherein the incident unit is disposed at a condensing position of reflected light emitted from the first surface of the collimator optical system. The optical member includes a planar incident surface on which light is incident so as to reflect a part of the light emitted from the light source, and is formed only of optical glass.
The light source device according to claim 1, wherein the optical system is arranged so that reflected light reflected by the optical member is incident thereon. Comprising at least one light source device according to any one of claims 1 to 4,
Of the light transmitted and reflected by the optical member, one is detected by the light detection unit, and the other is an image projection device used as projection light.