JP5440355B2 - Optical path synthesis device, illumination device, projection-type image display device, and electronic apparatus - Google Patents

Description

  The present invention relates to an optical path synthesis device that synthesizes light from a light source that emits light of different wavelengths into the same optical path, and an illumination device that synthesizes and emits light that is modulated and emitted from the plurality of light sources in the same direction. The present invention relates to a projection type image display device such as a laser scanning projector provided with the illumination device, and an electronic apparatus including the projection type image display device.

  In recent years, a projection type image display apparatus (hereinafter referred to as “projector”) using an LED, a laser, or the like has been actively developed, and is expected as a small and portable projector.

  For example, as described in Patent Document 1, a scanning small projector combining a laser of three primary colors and a MEMS (Micro Electro Mechanical Systems) mirror has few components and can be miniaturized. Many developments are underway.

  FIG. 11 shows a conventional example of a scanning projector comprising such three primary color lasers and a MEMS mirror. In the projector shown in FIG. 11, the semiconductor lasers 1-R, 1-G, 1-B that emit laser beams of R (red), G (green), and B (blue), respectively, and the semiconductor laser 1-R, Lenses 2-R, 2-G, 2-B that condense laser light from 1-G and 1-B, and dichroic that reflects only red light, green light, and blue light and transmits other light, respectively. Mirrors 3-R, 3-G, 3-B, MEMS (Micro Electro Mechanical Systems) 501 with mirrors with variable tilt angles, and mirrors of MEMS mirror device 501 are rotated in the horizontal and vertical directions. And a control circuit 502 that emits laser light whose light intensity is modulated from the semiconductor lasers 1-R, 1-G, and 1-B in accordance with the input video signal. The control circuit 502 includes a mirror control unit and a modulation unit, and forms an image on the screen 503 by modulating the laser light intensity in synchronization therewith.

  For example, as described in Patent Document 2, three light sources, red, green, blue, 601R, 601G, and 601B are combined by a dichroic prism 602 and condensed by a condenser lens 603, for example. As shown in FIG.

  In such a configuration, the number of condensing lenses is one, but the dichroic prism 602 is composed of right-angled triangular prisms having the same shape. That is, a prism having the same thickness is inserted between the light source and the lens.

  The color synthesizing method described in Patent Document 1 requires a condensing lens for each laser, which increases the number of parts, and causes a problem that hinders reduction in size and weight.

  In the method described in Patent Document 2, since the optical material has different refractive indices for different wavelengths, this configuration allows the lens to be optimized for one wavelength. For other wavelengths, spherical aberration occurs. That is, there is a problem that it is difficult to realize a lens having a small aberration for all light having different wavelengths.

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide an optical path synthesis device, an illumination device, a projection image display device, and an electronic apparatus that can contribute to miniaturization and improvement of wavefront quality of a light beam. To do.

In order to solve the above problems, an optical path combining device according to the present invention combines at least two light sources having different wavelengths, a right-angle prism that combines light from at least two light sources into the same optical path, and the same optical path. A right-angle prism is formed by bonding four right-angled triangular prisms of different sizes so that the right-angled portions are gathered in one place. Features.

  According to the present invention, it is possible to provide an optical path synthesis device, an illumination device, a projection-type image display device, and an electronic device that can contribute to miniaturization and improvement of wavefront quality of a light beam.

1 is a configuration diagram of an optical path synthesis device according to a first embodiment of the present invention. It is a block diagram of the coupling lens 5 which concerns on embodiment of this invention. It is a figure which shows the performance simulation result of the coupling lens of this embodiment. It is a figure which shows the relationship between the focal distance f of the coupling lens 5 with respect to each wavelength, and the thickness of the dichroic prism 4. FIG. It is a figure which shows the relationship between the focal distance f of the coupling lens 5 with respect to each wavelength, and the thickness of the dichroic prism 4. FIG. It is a figure which shows the example of a design of the coupling lens 5 designed using the dichroic prism. It is a block diagram of the optical path synthesis apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram of the projection type image display apparatus which concerns on the 3rd Embodiment of this invention. It is a block diagram of the MEMS mirror which concerns on this embodiment. It is a figure which shows the electronic device which concerns on the 4th Embodiment of this invention. It is a block diagram of the scanning projector which consists of the laser of the conventional 3 primary colors, and a MEMS mirror. It is a figure which shows the example which synthesize | combines the light of the conventional 3 colors light source, respectively red, green, blue, 601R, 601G, and 601B with the dichroic prism 602, and condenses with the condensing lens 603. FIG.

  Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a configuration diagram of an optical path synthesis device according to the first embodiment of the present invention.

  The optical path synthesis device includes a first light source 1 that emits light having a first wavelength λ1, a second light source 2 that emits light having a second wavelength λ2, and a third light that emits light having a third wavelength λ3. A light source 3, a dichroic prism 4, and a coupling lens 5 are provided. The light emitted from each light source is combined in the optical path by the dichroic prism 4, enters the coupling lens 5, and exits the coupling lens in a state where the optical axes of the respective light fluxes coincide.

  The first light source 1 is a semiconductor laser that emits light in the red wavelength region (hereinafter referred to as “red LD”), and the second light source 2 is a semiconductor laser that emits light in the green wavelength region (hereinafter referred to as “green LD”). As the third light source 3, a semiconductor laser that emits light in the blue wavelength region (hereinafter referred to as “blue LD”) can be used.

  The red, green, and blue wavelength regions refer to wavelength ranges of approximately 600 nm to 700 nm, 500 nm to 580 nm, and 400 nm to 480 nm, respectively. As the red LD, for example, an LD that emits light having a wavelength λ1 of 640 nm is a green LD. For example, an LD that emits light having a wavelength λ2 of 530 nm can be used, and an LD that emits light having a wavelength λ1 of 445 nm can be used as a blue LD. Below, it demonstrates based on this wavelength.

  FIG. 2 is a configuration diagram of the coupling lens 5 according to the present embodiment.

  As shown in FIG. 2, the performance of the coupling lens 5 was simulated by entering a light beam from the light beam emission side of the coupling lens 5.

  The simulation result is shown in FIG. The horizontal axis is the image height (mm), and the vertical axis is the wavefront aberration (λ). The broken line indicates the coupling lens performance designed in the state where the dichroic prism 4 is formed by the right-angle prism having the same shape, and the solid line indicates the coupling lens performance in the case where the dichroic prism 4 is formed by the right-angle prism having a different size. Indicates.

  The diameters of the incident light beams were both 2 (mm), and the focal length f of the coupling lens 5 was about 5 (mm).

  4 and 5 are diagrams illustrating the relationship between the focal length f of the coupling lens 5 and the thickness of the dichroic prism 4 with respect to each wavelength.

  FIG. 4 shows a case where the dichroic prism 4 is formed of right-angle prisms having the same shape, and FIG. 5 shows a case where the dichroic prism 4 is formed of right-angle prisms of different sizes.

  Here, the thickness of the dichroic prism with respect to the light of each wavelength is the distance that the light of the optical axis of the light source of each wavelength passes through the dichroic prism, and as shown in FIG. The thickness of the dichroic prism is distance AX + distance XD, the thickness of the dichroic prism with respect to light with a wavelength of λ2 is distance BX + distance XD, and the thickness of the dichroic prism with respect to light with a wavelength of λ3 is distance CX + distance XD. .

  The distance AX, the distance BX, and the distance CX correspond to the height of each right-angle prism.

  FIG. 6 is a design example of the coupling lens 5 designed using the dichroic prism of the present invention. The surface shapes of the 5-1 plane and the 5-2 plane shown in FIG. 2 are shown.

  In the above embodiment, a right-angle prism is described as an example. However, the present invention is not limited to this, and any dichroic prism having a configuration in which prisms are bonded to each other is applicable.

  FIG. 7 is a configuration diagram of an optical path synthesis device according to the second embodiment of the present invention.

  The optical path synthesis device includes a first light source 1 that emits light having a first wavelength λ1, a second light source 2 that emits light having a second wavelength λ2, and a third light that emits light having a third wavelength λ3. A light source 3. The light emitted from each light source passes through parallel plates 101, 102, and 103 having different thicknesses, and then the optical path is synthesized by a dichroic prism 104 having a structure in which right-angle prisms of equal size are bonded together, and enters a coupling lens 5. Then, the coupling lens is emitted in a state where the optical axes of the respective light fluxes coincide with each other.

  In the present embodiment, the same effect as that of the embodiment shown in FIG. 1 can be obtained even when parallel plates 101, 102, and 103 having different thicknesses are used in a dichroic prism having a structure in which right-angle prisms having the same size are bonded.

  In the above embodiment, a right-angle prism is described as an example. However, the present invention is not limited to this, and any dichroic prism having a configuration in which prisms are bonded to each other is applicable.

  FIG. 8 is a configuration diagram of a projection type image display apparatus according to the third embodiment of the present invention.

  This embodiment shows an example of a scanning projector (projection-type image display device) in which the optical path synthesis device shown in FIG. 1 is applied as an illumination device.

  Components and parts having the same functions as those in FIG. In the scanning projector (projection-type image display device) 30 shown in FIG. 8, in addition to the illumination device (optical path synthesis device) 20 shown in FIG. 1, scanning means for two-dimensionally scanning light emitted from the illumination device. 50, and a control unit 51 that controls the light source of the scanning unit 50 and the illumination device 20.

  The control device 51 modulates the light source so that a desired image is added in synchronization with the movement of the scanning means 50. The scanning unit 50 can swing the reflecting surface in the direction of the arrow 52 in FIG. 8, and can also swing the reflecting surface in the direction of the arrow 54 around the axis 53.

  As a result, a two-dimensional projection image is formed on the screen 55.

  As the scanning means 50, a galvanometer mirror, a polygon mirror, a MEMS mirror manufactured using a semiconductor process technology, or the like can be used. In particular, the MEMS mirror is extremely small and has low power consumption, and is most suitable for application to a small projector.

  Although FIG. 8 shows a single sheet movable in two axes, two mirrors movable in one axis may be used.

  FIG. 9 is a configuration diagram of the MEMS mirror according to the present embodiment.

  The MEMS mirror 90 that can be used as the scanning unit 50 of the present embodiment has a structure in which a micromirror 91 having a reflecting surface is supported by torsion bars 92 and 93. The micro mirror 91 reciprocates about the shaft 94 when the torsion bar 92 is twisted. Further, when the torsion bar 93 is twisted, a reciprocating motion about the shaft 95 is performed. By the reciprocating motion about both the axes 94 and 95, the normal direction of the deflection surface of the micromirror 91 changes two-dimensionally.

  For this reason, the reflection direction of the beam incident on the micromirror 91 is changed, so that the beam can be scanned in a two-dimensional direction.

  Further, the projection type image display apparatus 30 realized by the configuration of the present embodiment can be miniaturized by reducing the size of the light source unit and the micromirror.

  FIG. 10 is a diagram showing an electronic apparatus according to the fourth embodiment of the present invention.

  An example in which the projection type image display apparatus shown in the third embodiment mobile phone is built in an electronic apparatus will be described.

  FIG. 10 shows an example in which a micro-projection image display device 71 is built in a mobile phone 70. A cellular phone 70 incorporates an ultra-compact projection type image display device 71 and scans illumination light 72 on a screen 73 two-dimensionally to form an image. The screen 73 is not special and may be a desk or a wall, for example.

  In the present embodiment, an example in which the mobile phone is built in is shown. However, the present invention is not limited to this. For example, a digital camera, a notebook computer, a PDA, or the like may be used.

  According to the above embodiment, since light from three light sources having different wavelengths is optically combined by a single dichroic prism having a different thickness for each wavelength, the combined light is coupled by a single coupling lens. Thus, it is possible to configure a small-sized and low-aberration illumination device.

  Further, according to the above embodiment, the light from the three light sources having different wavelengths is optically combined by the single dichroic prism having different thicknesses for each wavelength, so that the combined light is coupled by the single coupling lens. It becomes possible to ring, and it is possible to configure a small-sized illumination device with small aberration.

  Further, according to the above embodiment, the illumination device, the means capable of two-dimensionally scanning the light emitted from the illumination device, and the outputs of three light sources having different wavelengths are synchronized with the movement of the operation means. Therefore, it is possible to realize a projection type image display apparatus that is small and has a small spot aberration on the projection surface.

  According to the above embodiment, since the projection type image display device is built in the electronic device, the image and video data of the electronic device can be projected on the screen on the spot, and information can be easily shared among a plurality of people. Can be done.

  The above-described embodiment is a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiment alone, and various modifications are made without departing from the gist of the present invention. Implementation is possible.

  The prism of the optical path synthesizer according to the present invention is characterized in that the higher the wavelength of light transmitted, the higher the prism.

  An illumination device according to the present invention includes the above-described optical path synthesis device.

  According to the present invention, there is provided a projection-type image display device including the above-described illumination device, a scanning unit capable of two-dimensionally scanning light emitted from the coupling lens of the illumination device, and having at least two or more wavelengths. And control means for controlling outputs from different light sources in synchronization with the movement of the operation means.

  An electronic apparatus according to the present invention includes the projection type image display device described above.

  INDUSTRIAL APPLICABILITY According to the present invention, the present invention can be applied to applications such as an optical path synthesis device, an illumination device, an image display device, a digital camera, a notebook computer, a PDA, and other electronic devices.

DESCRIPTION OF SYMBOLS 1 1st light source 2 2nd light source 3 3rd light source 4 Dichroic prism 5 Coupling lens 5-1, 5-2 Lens surface 6, 7, 8, 9 Lens 10 Parallel plate 20 Illuminating device (optical path combining device)
30 Scanning projector (projection type image display device)
DESCRIPTION OF SYMBOLS 50 Scanning means 51 Control apparatus 52, 54 Arrow 53 Axis 55 Screen 70 Cellular phone 71 Miniature projection type image display apparatus 72 Illumination light 73 Screen 90 MEMS mirror 91 Micro mirror 92, 93 Torsion bar 94, 95 Axis 101, 102, 103 , 104 Parallel plate 502 Control circuit 503 Screen 601R, 601G, 601B Light 602 Dichroic prism 603 Condensing lens

Japanese Patent No. 4031481 JP 2001-154607 A

Claims (5)

At least two different light sources of different wavelengths;
A right angle prism that combines light from the at least two light sources into the same optical path;
A coupling lens for coupling light synthesized in the same optical path;
Have
The right-angle prism is configured by bonding four right-angled triangular prisms having different sizes so that the respective right-angled spots are gathered in one place . The right-angle prism, the optical path synthesizing apparatus according to claim 1, wherein the height of the right-angle prism light of long wavelength corresponding to the height of the right triangle as those which transmits high.   An illumination device comprising the optical path synthesis device according to claim 1. Scanning means capable of two-dimensionally scanning light emitted from the coupling lens of the illumination device;
Control means for controlling the output from the light sources having different wavelengths of at least two or more in synchronization with the movement of the operation means;
A projection-type image display device comprising the illumination device according to claim 3.   An electronic apparatus comprising the projection type image display device according to claim 4.

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