JP2019061110A - Luminaire apparatus and projector - Google Patents

Abstract

To provide a small size luminaire apparatus with little generation of speckle noises.SOLUTION: Disclosed luminaire apparatus comprises: a light source unit which includes: a first light-emitting device that outputs first light having a first wavelength; a second light-emitting device that outputs second light having a second wavelength, and which outputs light including the first light and the second light; a focusing optics for focusing the light output from the light source unit to a predetermined focusing position; and a diffusion portion for diffuses the light output from the focusing optics, which is disposed at a predetermined focusing position. The diffusion portion has diffusion characteristics such that the diffusion characteristic of the first light and the diffusion characteristic of the second light are different from each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lighting device and a projector.

  In recent years, projectors using a laser light source, which is a light source with a wide color gamut and high efficiency, are attracting attention for the purpose of enhancing the performance of the projector. For example, in Patent Document 1 below, a light source device having lasers of three colors of red, green, and blue, which are individually disposed, and two dichroic prisms that sequentially combine light emitted from lasers of the respective colors. And the projector provided with this is disclosed.

JP, 2013-231940, A

By the way, the laser light source has a problem of generation of speckle noise. In order to solve this problem, a method such as driving an optical element that transmits laser light is often used. In patent document 1, the optical element by which the unevenness | corrugation was formed in the surface is arrange | positioned between two fly eye lenses, and the structure which vibrates this optical element is employ | adopted. Besides, a method of rotating the diffusion plate using a motor has also been proposed.
However, due to factors such as the light output required to achieve the desired color balance not being the same for each emission color, and the current light output per laser chip being different for each emission color, the laser for each emission color The number of light sources used can not be the same.

  When the number of laser light sources is different for each emission color, the incident angle of light to the diffusion plate is different for each emission color, so the diffusion characteristics of the diffusion plate also need to be different for each emission color. This problem can be solved by separately arranging a diffuser having different diffusion characteristics for each light path of light of each luminescent color. However, in this configuration, the number of diffusion plates used increases, and a new problem arises that the illumination device becomes large.

  One aspect of the present invention is made to solve the above-described problems, and an object of the present invention is to provide a small-sized lighting device with less occurrence of speckle noise. Another object of the present invention is to provide a projector provided with the lighting device described above.

  In order to achieve the above object, a lighting device according to one aspect of the present invention comprises: a first light emitting device emitting a first light having a first wavelength; and a second light emitting device different from the first wavelength And a second light emitting device for emitting a second light having a wavelength of, a light source unit for emitting light including the first light and the second light, and emission from the light source unit A condensing optical system that condenses the emitted light at a predetermined condensing position; and a diffusion unit that is disposed at the predetermined condensing position and diffuses the light emitted from the condensing optical system, In the diffusion portion, the diffusion characteristics for the first light and the diffusion characteristics for the second light are different from each other.

  In the lighting device according to one aspect of the present invention, the diffusion characteristics for the first light and the diffusion characteristics for the second light in the diffusion portion are different from each other. As a result, even if the number of first light emitting devices and the number of second light emitting devices are different, and even if the incident angles of light of each light emitting color are different from each other, the diffusion angle distribution of the first light and the second light The diffusion angle distributions can be brought close to each other to compensate for the lack of diffusion performance for one light. As a result, the generation of speckle noise can be suppressed. Moreover, according to this configuration, since it is not necessary to dispose the diffusion unit having different diffusion characteristics for each light path of light having different wavelengths, a compact illumination device can be realized.

  In the lighting device according to one aspect of the present invention, the diffusion unit has a light transmission having a first surface on which light emitted from the light collecting optical system is incident, and a second surface different from the first surface. And the first surface transmits and diffuses the first light and reflects and diffuses the second light, and the second surface transmits and diffuses the first light. It may be configured to reflect light.

  According to this configuration, the first light emitted from the light collection optical system is diffused once when it passes through the first surface and enters the interior of the translucent substrate, and then is reflected by the second surface When the light is transmitted through the first surface and emitted from the light transmitting substrate, the light is diffused again. On the other hand, the second light emitted from the light collection optical system is diffused once when it is reflected by the first surface, and does not enter the interior of the light transmitting substrate. Thus, by diffusing the first light twice on the first surface and diffusing the second light once on the first surface, the diffusion characteristics of the first light and the diffusion characteristics of the second light And different diffusion units can be realized.

  In the lighting device according to one aspect of the present invention, the light source unit further includes a third light emitting device that emits third light having a third wavelength different from the first wavelength and the second wavelength; The first light, the second light and the third light are emitted in a first direction, and the number of the second light emitting devices is greater than the number of the first light emitting devices The second light emitting device is provided in rotational symmetry around a central axis of the first light so as to surround the first light emitting device, and the number of the third light emitting devices is the first light emitting device. The third light emitting devices may be provided so as to be rotationally symmetrical around the central axis of the first light so as to surround the first light emitting devices.

  According to this configuration, the occupied area of the light source unit including the first light emitting device, the second light emitting device, and the third light emitting device can be reduced. This makes it possible to realize a compact light source unit capable of emitting light including light of three different colors. Further, the central axis of the second light of the second wavelength and the central axis of the third light of the third wavelength can be aligned with the central axis of the first light of the first wavelength.

  In the lighting device according to one aspect of the present invention, the diffusion unit has a diffusion characteristic to the first light and a diffusion characteristic to the third light that are different from each other, and the third light is transmitted to the first surface. It may be configured to reflect and diffuse.

  According to this configuration, the first light emitted from the light collection optical system is diffused once when it passes through the first surface and enters the interior of the translucent substrate, and then is reflected by the second surface When the light is transmitted through the first surface and emitted from the light transmitting substrate, the light is diffused again. On the other hand, the third light emitted from the light collection optical system is diffused once when it is reflected by the first surface, and does not enter the interior of the light transmitting substrate. Thus, the first light is diffused twice on the first surface, and the third light is diffused once on the first surface, so that the first light diffusion characteristics and the third light diffusion characteristics And different diffusion units can be realized.

  In the lighting device according to one aspect of the present invention, the first light is blue, the second light is green, the third light is red, and the light source unit is a single light source. A first light emitting device, three of the second light emitting devices, and three of the third light emitting devices may be provided.

  According to this configuration, a compact light source device capable of emitting white light can be realized.

  In the lighting device of one aspect of the present invention, the first surface may include an anti-reflection film that prevents the reflection of the first light.

  According to this configuration, the ratio of the first light incident on the inside of the light transmitting substrate can be increased, so that the first light can be sufficiently diffused.

  In the illumination device according to one aspect of the present invention, the diffusion unit is a diffusion plate that is irradiated with the light condensed by the condensing optical system and diffuses the light, and a rotating unit that rotates the diffusion plate. And may be provided.

  According to this configuration, light whose diffusion angle distribution changes temporally is emitted from the lighting device, so that it is possible to provide a lighting device with less speckle noise.

  A projector according to an aspect of the present invention includes: the illumination device according to the aspect of the present invention; a light modulation device that forms image light by modulating light from the illumination device according to image information; and the image light And a projection optical device that projects the light.

  According to this configuration, a compact projector capable of projecting an image with less speckle noise can be realized.

It is a schematic block diagram of the projector of 1st Embodiment. It is a perspective view of a light source device. It is a front view of a light source device. It is an enlarged view of the principal part of a lighting installation. It is a figure which shows the optical path of the blue light in a diffusion plate. It is a figure which shows the optical path of the green light in a diffusion plate. It is a figure which shows the optical path of the red light in a diffusion plate. It is a schematic block diagram of the projector of 2nd Embodiment.

First Embodiment
Hereinafter, a first embodiment of the present invention will be described using FIGS. 1 to 7.
The projector of the present embodiment is an example of a liquid crystal projector provided with a light source device using a semiconductor laser.
In addition, in order to make each component intelligible in the following each drawing, the reduced scale of a dimension may be shown differently by component.

  The projector 10 of the present embodiment is a projection type image display device that displays a color image on a screen (projected surface) SCR. The projector 10 uses three light modulation devices corresponding to the respective color lights of red light LR2, green light LG2, and blue light LB2. The projector 10 uses, as a light emitting element of the light source device, a semiconductor laser capable of obtaining light with high brightness and high output.

FIG. 1 is a schematic configuration diagram of a projector 10 of the present embodiment.
As shown in FIG. 1, the projector 10 includes an illumination device 700, a color separation light guide optical system 200, a red light light modulation device 400R, a green light light modulation device 400G, and a blue light light modulation device 400B. , A synthetic optical system 500, and a projection optical device 600. The red light light modulation device 400R, the green light light modulation device 400G, and the blue light light modulation device 400B modulate the light from the illumination device 700 according to image information to form image light. The projection optical device 600 projects image light.

  The illumination device 700 includes a light source device 710, a condensing optical system 720, a diffusion device 740 (diffusion unit), a pickup optical system 730, and an integrator optical system 780. In the illumination device 700, the diffusion device 740, the pickup optical system 730, and the integrator optical system 780 are provided on the optical axis AX0 that coincides with the central axis of the light LW emitted from the illumination device 700. The light source device 710, the focusing optical system 720, and the diffusion device 740 are provided on an optical axis AX1 orthogonal to the optical axis AX0.

  Hereinafter, the direction in which the light LW is emitted from the lighting device 700 is referred to as Y direction, the direction in which light is emitted from the light source 710 is referred to as X direction, and the direction perpendicular to the X direction and the Y direction is referred to as Z direction. The optical axis AX1 is parallel to the X axis, and the optical axis AX0 is parallel to the Y axis.

FIG. 2 is a perspective view of the light source device 710. In FIG. 2, in order to make the drawing easy to see, illustration of the pedestals of some semiconductor lasers is omitted.
FIG. 3 is a front view of the light source device 710 as viewed from the light emission direction.
As shown in FIGS. 2 and 3, the light source device 710 includes a light source unit 750 and a holding member 712. The light source unit 750 includes at least one blue semiconductor laser 711 B (first light emitting device), a plurality of green semiconductor lasers 711 G (second light emitting devices), and a plurality of red semiconductor lasers 711 R (third light emitting devices). And.

  In the present embodiment, the light source unit 750 includes one blue semiconductor laser 711B, three green semiconductor lasers 711G, and three red semiconductor lasers 711R. The reason why the above example is preferable as the number of semiconductor lasers of each emission color will be described later.

  However, depending on the case, the light source device 710 may include a plurality of blue semiconductor lasers 711B, as long as it includes at least one blue semiconductor laser 711B. Further, the number of green semiconductor lasers 711 G and red semiconductor lasers 711 R may not necessarily be three. Also, the number of green semiconductor lasers 711G and the number of red semiconductor lasers 711R may be different.

  The blue semiconductor laser 711B emits blue light LB (first light having a first wavelength) having a first wavelength in the X direction (first direction). The first wavelength is, for example, 455 nm ± 20 nm. The green semiconductor laser 711G emits a green light beam LG1 having a second wavelength in the X direction (first direction). The second wavelength is, for example, 550 nm ± 30 nm. The red semiconductor laser 711R emits a red light beam LR1 having a third wavelength in the X direction (first direction). The third wavelength is, for example, 635 nm ± 20 nm.

  That is, each of the blue semiconductor laser 711B, the green semiconductor laser 711G, and the red semiconductor laser 711R emits color lights LB, LG1, and LR1 of different colors in the same direction. As a result, white light including the three color lights LB, LG1, and LR1 is emitted as the entire light source device 710 (light source unit 750).

  In the following description, the three green light beams LG1 emitted from the three green semiconductor lasers 711G are combined and referred to as a green light LG (second light having a second wavelength different from the first wavelength). The three red light beams LR1 emitted from the three red semiconductor lasers 711R are collectively referred to as red light LR (third light having a third wavelength different from the first wavelength and the second wavelength).

  Each of the blue semiconductor laser 711B, the green semiconductor laser 711G, and the red semiconductor laser 711R is configured of a CAN package type semiconductor laser. As shown in FIG. 2, each package 716 consisting of a pedestal 713 and a can 714 covering one surface side of the pedestal 713 includes one or more semiconductor laser chips 715 B and one or more semiconductor laser chips 715 B, as shown in FIG. A semiconductor laser chip 715G or one or more semiconductor laser chips 715R are accommodated.

  The blue semiconductor laser 711B includes a blue semiconductor laser chip 715B and a blue light package 716B that houses the blue semiconductor laser chip 715B.

  The green semiconductor laser 711G includes a green semiconductor laser chip 715G and a green light package 716G that houses the green semiconductor laser chip 715G.

  The red semiconductor laser 711R includes a red semiconductor laser chip 715R and a red light package 716R that accommodates the red semiconductor laser chip 715R therein.

  Each of the blue light casing 716 B, the green light casing 716 G, and the red light casing 716 R includes a pedestal 713 and a can 714. Further, in the example of FIG. 3, one semiconductor laser chip 715B, 715G, 715R is accommodated in each of the housings 716B, 716G, 716R, but a plurality of semiconductor laser chips 715B, 715G, 715R are respectively It may be housed inside the housings 716B, 716G, 716R.

  Since the luminous efficiency of the semiconductor laser (semiconductor laser chip) differs for each luminescent color, the light output of the semiconductor laser also differs for each luminescent color. That is, the luminous efficiency of the blue semiconductor laser 711B is higher than the luminous efficiency of the green semiconductor laser 711G and the luminous efficiency of the red semiconductor laser 711R. Even when the light emission efficiency of the semiconductor laser chip is relatively low, the light output emitted from the semiconductor laser chip can be increased by increasing the input power input to the semiconductor laser chip, but the increase in input power This raises the temperature of the semiconductor laser chip and causes a decrease in light emission efficiency and a decrease in lifetime. Therefore, if the input power is the same, the light output of the blue semiconductor laser 711B is higher than the light output of the green semiconductor laser 711G and the light output of the red semiconductor laser 711R.

As an example, Nichia Chemical Industry Co., Ltd., website, product information, "Laser diode (LD)" [online], [search on September 14, 2017], Internet <URL: http: //www.nichia Output of the blue semiconductor laser (Model No .: NDB7K75) is, for example, 3.5 W (use temperature: 25 ° C.), and the green semiconductor laser (Model No .: NDG7K75T) The light output of) is, for example, 1 W (use temperature: 25.degree. C.). Although not described in the above-mentioned homepage, a blue semiconductor laser array (model number: NUBM08-02) is provided, and this blue semiconductor laser array has a plurality of blue semiconductor lasers having a light output of 4.5 W (25 ° C.) Have.
Mitsubishi Electric Corporation website, news release, "Notice of 639nm red high power semiconductor laser released for projector" [online], [search on September 14, 2017], Internet <URL: http: //www.mitsubishielectric. According to co. jp / news / 2016 / 1214. html, the light output of the semiconductor laser for red light (model number: ML562G85) is, for example, 2.1 W (25 ° C.).

  When the light output at the above temperature 25 ° C. is converted to the light output at the actual use temperature 45 ° C., the light output of the semiconductor laser of each light emission color is as shown in Table 1 below.

  That is, the light output of one blue semiconductor laser (model number: NDB7K75) is 2.8 W, and the light output of one blue semiconductor laser included in the blue semiconductor laser array (model number: NUBM 08-02) is 4.1 W. The light output of one green semiconductor laser (model number: NDG7K75T) is 0.8 W, and the light output of one red semiconductor laser (model number: ML562G85) is 1.26 W.

  On the other hand, the light output of the semiconductor laser for each light emission color necessary to obtain white light (color temperature 6500 K) having a brightness of 1000 lm, 2000 lm, and 3000 lm, respectively, and for each light emission color required to obtain this white light The number of semiconductor lasers (CAN package type semiconductor lasers) is as shown in Table 2 below.

  As shown in the lowermost row of Table 2, the light output of the semiconductor laser for each emission color required to obtain white light with a brightness of 1000 lm is 1.23 W for the blue semiconductor laser and 2.3 W for the green semiconductor laser. It is 03 W and the red semiconductor laser is 2.92 W. Calculated from the required light output value [W] in Table 2 and the light output [W / piece] of the semiconductor laser per one in Table 1, the number of semiconductor lasers required to obtain white light with a brightness of 1000 lm There are one blue semiconductor laser (model number: NDB7K75), three green semiconductor lasers (model number: NDG7K75T), and three red semiconductor lasers (model number: ML562G85). This corresponds to the number of semiconductor lasers 711B, 711G, and 711R of the light source device 710 (light source unit 750) of the present embodiment. However, in Table 2, for the brightness of 3000 lm, one blue semiconductor laser included in the blue semiconductor laser array (model number: NUBM 08-02) is used.

  From the above, the light output of the light source device 710 of the present embodiment is suitable as a light source device of a small projector having a luminous flux of about 1000 lm.

  When one semiconductor laser includes one semiconductor laser chip, the luminous efficiency of the semiconductor laser is equal to the luminous efficiency of the semiconductor laser chip. When one semiconductor laser includes a plurality of semiconductor laser chips, the luminous efficiency of the semiconductor laser is equal to the sum of the luminous efficiencies of the plurality of semiconductor laser chips.

  According to the inventor's guess, it is possible that the light output of the semiconductor lasers 711 B, 711 G and 711 R of each light emission color may increase more than the above-mentioned values with the advance of the semiconductor laser technology in the future. The ratio of the number of semiconductor lasers 711 B, 711 G, 711 R of each color required for the same does not change. Therefore, in the present embodiment, the light source device 710 including one blue semiconductor laser 711B, three green semiconductor lasers 711G, and three red semiconductor lasers 711R is illustrated, but the number of semiconductor lasers is not limited to this example. It is not limited to.

  The holding member 712 corresponds to the number of the plurality of semiconductor lasers 711B, 711G, and 711R, and is formed of a circular plate material provided with seven holes corresponding to the dimensions of the can body 714. Although the material of the plate material is not particularly limited, for example, a metal having high thermal conductivity is desirable. Each of the plurality of semiconductor lasers 711 B, 711 G, 711 R is supported by the holding member 712 by one surface of the pedestal 713 contacting the holding surface 712 a of the holding member 712 in a state where the can 714 is inserted into the hole of the holding member 712 It is done. As described above, the holding member 712 has the holding surface 712a disposed so as to face the side opposite to the light emission direction of the plurality of semiconductor lasers 711B, 711G, and 711R.

  As shown in FIG. 3, among the plurality of semiconductor lasers 711 B, 711 G, and 711 R, the blue semiconductor laser 711 B is disposed on the holding member 712 so as to be positioned at the central portion of the light source unit 750. The plurality of green semiconductor lasers 711G and the plurality of red semiconductor lasers 711R are disposed in the peripheral region of the blue semiconductor laser 711B in the holding member 712 so as to surround the blue semiconductor laser 711B.

  The green semiconductor laser 711G and the red semiconductor laser 711R are disposed on the holding member 712 so as to be located on a virtual circle centered on the blue semiconductor laser 711B. The green semiconductor laser 711G and the red semiconductor laser 711R are alternately provided along the circumferential direction of the virtual circle.

  The center of the virtual circle may coincide with the central axis C1 (see FIG. 5) of the blue light LB of the blue semiconductor laser 711B. The central axis of the light of the red light beam LR1 emitted by each of the red semiconductor lasers 711R may be on the imaginary circle. The central axis of the light of the green light LG1 emitted by each of the green semiconductor lasers 711G may be on the imaginary circle.

According to the above arrangement, in the light source unit 750, the angles formed by the plurality of straight lines m connecting the light emission centers of the blue semiconductor laser 711B, the green semiconductor laser 711G and the red semiconductor laser 711R are equal to one another.
In addition, the lengths of the arcs of the respective fan-shaped arcs, each having a central angle formed by three straight lines m around the central axis C1 (see FIG. 5) of the blue light LB of the blue semiconductor laser 711B, They are equal to each other. The central angles of the plurality of sectors are equal to one another, all at 60 °.
Similarly, the lengths of the arcs of the respective fan-shaped arcs whose central angles are the angles formed by the three straight lines m at and near the semiconductor laser chip 715B are equal to one another. The central angles of the plurality of sectors are equal to one another, all at 60 °.

  In the plurality of semiconductor lasers 711 B, 711 G, and 711 R, the blue light casing 716 B, the green light casing 716 G, and the red light casing 716 R of the adjacent semiconductor lasers abut each other at the pedestal 713 portion. The pedestals 713 of the plurality of semiconductor lasers 711G and 711R may not be in contact with each other. That is, the central axes of the red light beam LR1 emitted by the red semiconductor laser 711R and the central axes of the green light beam LG1 emitted by the green semiconductor laser 711G may be alternately arranged at equal intervals on a virtual circle. .

As described above, the plurality of green semiconductor lasers 711G are provided in rotational symmetry around the central axis of the blue light LB in the peripheral region of the blue semiconductor laser 711B. Further, the plurality of red semiconductor lasers 711R are provided in rotational symmetry around the central axis of the blue light LB in the peripheral region of the blue semiconductor laser 711B.
The plurality of green semiconductor lasers 711G may be provided so as to be rotationally symmetric around the central axis of the blue light LB so as to surround the blue semiconductor laser 711B as long as the above-described arrangement and positional relationship are satisfied. Similarly, the plurality of red semiconductor lasers 711R are provided so as to be rotationally symmetric around the central axis of the blue light LB so as to surround the blue semiconductor laser 711B, satisfying the above-described arrangement and positional relationship. Just do it.

  The blue semiconductor laser 711B, the green semiconductor laser 711G, and the red semiconductor laser 711R are arranged such that the directions (long sides of the rectangular semiconductor laser chip) of the semiconductor laser chips 715B, 715G, 715R are the same. In the example shown in FIG. 3, the blue semiconductor laser 711B, the green semiconductor laser 711G, and the red semiconductor laser 711R are arranged such that the long sides of the semiconductor laser chips 715G and 715R are parallel to the Y axis.

  As described above, the blue semiconductor laser 711B, the green semiconductor laser 711G, and the red semiconductor laser 711R are disposed in the same direction (long side of the rectangular semiconductor laser chip) of the semiconductor laser chips 715B, 715G, 715R. The blue semiconductor laser 711 B and the green semiconductor laser 711 G, and the red semiconductor laser 711 R emit linearly polarized light in different directions due to the difference in oscillation mode. Specifically, the blue semiconductor laser 711 B and the green semiconductor laser 711 G emit P-polarized light to the diffusion plate 741, and the red semiconductor laser 711 R emits S-polarized light to the diffusion plate 741. In this case, the polarizing plates of the light modulators 400R, 400G, and 400B may be arranged in alignment with the polarization direction of light. In addition, the direction of the semiconductor laser chip 715R of the red semiconductor laser 711R is rotated 90 ° around the central axis of the emitted light (red ray LR1) with respect to the directions of the semiconductor laser chips 715B and 715G of the other semiconductor lasers 711B and 711G. By this, it is possible to make the direction of the linearly polarized light to be emitted the same.

  With the above configuration, the light source device 710 emits white light LW including the blue light LB, the green light LG, and the red light LR.

  As shown in FIG. 1, the condensing optical system 720 condenses the light LW emitted from the light source device 710 on a predetermined condensing position, specifically, on a diffusion plate 741 of a diffusing device 740 described later. The condensing optical system 720 is composed of one convex lens 721. The condensing optical system 720 may be composed of a plurality of lenses.

FIG. 4 is an enlarged view of the illumination device 700 including the light source device 710, the collection optical system 720, and the diffusion device 740.
As shown in FIG. 4, the diffusion device 740 includes a diffusion plate 741 and a motor 745 (rotation unit) for rotating the diffusion plate 741. The diffusion plate 741 has a first surface 741a on which the light emitted from the condensing optical system 720 is incident, and a second surface 741b opposite to the first surface 741a unlike the first surface 741a. . The diffusion device 740 is disposed at a predetermined condensing position of the condensing optical system 720 and diffuses the light emitted from the condensing optical system 720.

  The diffusion plate 741 is disposed such that the first surface 741a and the second surface 741b form an angle of 45 ° with the optical axis AX0 and the optical axis AX1, respectively. The light LW is diffused and reflected by the diffusion plate 741 to become diffused light having a predetermined angular distribution centered on the optical axis AX0, and is emitted from the diffusion device 740 toward the integrator optical system 780 shown in FIG.

FIG. 5 is a view showing an optical path of the blue light LB in the diffusion plate 741. As shown in FIG. FIG. 6 is a view showing an optical path of the green light LG in the diffusion plate 741. As shown in FIG. FIG. 7 is a view showing an optical path of the red light LR in the diffusion plate 741. As shown in FIG.
As shown in FIGS. 5 to 7, the diffusion plate 741 includes a translucent substrate 742, a diffusion structure 743, a wavelength selection film 746, an antireflection film 747, and a reflection film 748. The wavelength selective film 746 and the antireflective film 747 may be a film (multilayer film) having an integral structure. A film that exhibits a reflection preventing function for blue light and a reflection function for green light and red light can be realized by a dielectric multilayer film.

  The light transmitting substrate 742 is made of, for example, a light transmitting material such as glass. The diffusion structure 743 is composed of a concavo-convex portion formed on the first surface 742 a of the light-transmissive substrate 742 and has a smooth surface on which the wavelength selective film 746 and the antireflective film 747 can be coated. . As a specific example of the diffusion structure 743, for example, a microlens array, a holographic diffuser, a polished glass surface having a slightly melted surface, or the like is used.

  The wavelength selection film 746 is stacked on the diffusion structure 743 on the first surface 742 a of the translucent substrate 742. The wavelength selective film 746 is obtained, for example, by coating a dielectric multilayer film on the diffusion structure 743. The wavelength selective film 746 has characteristics of transmitting light in the blue range and reflecting light in the green range and the red range.

  The anti-reflection film 747 is stacked on the wavelength selection film 746 on the first surface 742 a of the translucent substrate 742. The antireflective film 747 is obtained, for example, by coating a dielectric multilayer film on the wavelength selective film 746. The antireflective film 747 has a characteristic of preventing reflection of light in the blue range.

  The reflective film 748 is formed on the second surface 742 b of the translucent substrate 742. The reflective film 748 is obtained, for example, by coating a dielectric multilayer film or a metal film such as silver or aluminum on the second surface 742 b of the translucent substrate 742. The reflective film 748 has a characteristic of reflecting light in the blue range. When the diffusion characteristic of blue light is insufficient only by the diffusion structure 743 of the first surface 742a, the second surface 742b of the translucent substrate 742 is similar to the first surface 742a. An uneven structure may be provided.

  According to the above configuration, the first surface 741a of the diffusion plate 741 has a function of transmitting and diffusing the blue light LB and reflecting and diffusing the green light LG and the red light LR. The second surface 741 b of the diffusion plate 741 has a function of reflecting the blue light LB.

  As shown in FIG. 5, the blue light LB is diffused by the diffusion structure 743 when passing through the first surface 742a and entering the interior of the translucent substrate 742 and then reflected by the second surface 742b. When the light is transmitted again through the first surface 742 a and emitted from the light transmitting substrate 742, the light is diffused again by the diffusion structure 743.

  As shown in FIG. 6, the green light LG is diffused by the diffusion structure 743 when being reflected by the first surface 742 a, and does not enter the inside of the translucent substrate 742. Similarly, as shown in FIG. 7, the red light LR is diffused by the diffusion structure 743 when it is reflected by the first surface 742 a and does not enter the interior of the translucent substrate 742. Thus, the blue light LB is diffused twice by the diffusion structure 743, while the green light LG and the red light LR are diffused once by the diffusion structure 743. That is, the diffusion characteristics for the blue light LB and the diffusion characteristics for the green light LG and the red light LR are different from each other.

  As shown in FIG. 4, the blue light LB is emitted from a single blue light semiconductor laser 711 B disposed at the center of the light source device 710. Thereafter, the blue light LB is condensed by the condensing optical system 720 and is incident on the diffusion plate 741.

  On the other hand, the green light LG composed of three green light rays LG1 is emitted from the three green light semiconductor lasers 711G provided in rotational symmetry around the central axis C1 of the blue light LB. Similarly, red light LR consisting of three red light beams LR1 is emitted from three red light semiconductor lasers 711R provided in rotational symmetry around the central axis C1 of blue light LB. Therefore, the central axis C2 of the green light LG coincides with the central axis C2 of the red light LR, and the central axis C2 coincides with the central axis C1 of the blue light LB.

  The green light LG and the red light LR are condensed by the condensing optical system 720 and enter the diffusion plate 741. At this time, the luminous flux width of the blue light LB is smaller than the luminous flux widths of the green light LG and the red light LR, and the incident angle distribution α1 of the blue light LB to the diffusion plate 741 is the green light LG and the red light LR to the diffusion plate 741. It is smaller than the incident angle distribution α2.

  Here, assuming that the number of times of diffusion of blue light LB and the number of times of diffusion of green light LG and red light LR in diffusion plate 741 is the same, blue light LB has an incident angle compared to green light LG and red light LR. The smaller the distribution, the smaller the diffusion angle distribution, and the smaller the speckle noise suppression effect. However, in the case of the present embodiment, as described above, the blue light LB is diffused twice by the diffusion plate 741, while the green light LG and the red light LR are diffused once by the diffusion plate 741. Therefore, even if the blue light LB has a smaller incident angle distribution than the green light LG and the red light LR, the diffusion angle distribution can be made equally large, and sufficient suppression effect of speckle noise can be obtained. it can.

  Returning to FIG. 1, the pickup optical system 730 is provided with a collimator lens 731. The collimator lens 731 collimates the light LW emitted from the diffusion plate 741 and emits the light LW toward the integrator optical system 780.

  The integrator optical system 780 includes a first lens array 781, a second lens array 782, and a superimposing lens 783. The integrator optical system 780 is an image forming area of the illuminance distribution of the light LW emitted from the collimator lens 731 for each of the red light light modulation device 400R, the green light light modulation device 400G, and the blue light light modulation device 400B. Make uniform in

  The first lens array 781 has a plurality of lenses 786 for dividing the light LW emitted from the diffuser 740 into a plurality of partial ray bundles. The plurality of lenses 786 are arranged in a matrix in a plane orthogonal to the optical axis AX0.

  The second lens array 782 includes a plurality of lenses 787 corresponding to the plurality of lenses 786 of the first lens array 781. The second lens array 782 combines the image of each lens 786 of the first lens array 781 with the superposing lens 783 at the rear stage with the red light light modulation device 400R, the green light light modulation device 400G, and the blue light light modulation. The image is formed at or near the image forming area of each of the apparatuses 400B. The plurality of lenses 787 are arranged in a matrix in a plane orthogonal to the optical axis AX0.

  The superimposing lens 783 condenses each partial light beam from the first lens array 781 and generates an image of each of the red light light modulation device 400R, the green light light modulation device 400G, and the blue light light modulation device 400B. They are superimposed on each other at or near the formation region.

  The color separation and light guide optical system 200 includes a dichroic mirror 240, a dichroic mirror 220, a reflection mirror 210, a reflection mirror 230, and a reflection mirror 250. The color separation light guide optical system 200 separates the white light LW emitted from the illumination device 700 into red light LR2, green light LG2 and blue light LB2, and red light LR2, green light LG2 and blue light LB2 The red light modulation device 400R, the green light modulation device 400G, and the blue light modulation device 400B are respectively led.

  A field lens 300R, a field lens 300G, and a field lens 300B are provided between the color separation light guide optical system 200 and the red light light modulation device 400R, the green light light modulation device 400G, and the blue light light modulation device 400B. Are arranged respectively.

  The dichroic mirror 240 reflects the blue light LB2 and transmits the red light LR2 and the green light LG2. The dichroic mirror 220 reflects the green light LG2 and transmits the blue light LB2. The reflection mirror 210 and the reflection mirror 230 reflect the red light LR2. The reflection mirror 250 reflects the blue light LB2.

  Each of the red light light modulation device 400R, the green light light modulation device 400G, and the blue light light modulation device 400B includes a liquid crystal panel that modulates incident color light according to image information to form an image. ing.

  Although illustration is omitted, light is incident between the field lens 300R, the field lens 300G, the field lens 300B, the red light light modulation device 400R, the green light light modulation device 400G, and the blue light light modulation device 400B. A side polarizer is arranged. Between the light modulation device for red light 400R, the light modulation device for green light 400G, the light modulation device for blue light 400B, and the combining optical system 500, an emission side polarization plate is disposed.

  The combining optical system 500 combines the image lights emitted from the red light light modulation device 400R, the green light light modulation device 400G, and the blue light light modulation device 400B. The composite optical system 500 is formed of a cross dichroic prism having a substantially square shape in plan view and four right-angled prisms bonded together, and a dielectric multilayer film is provided at a substantially X-shaped interface where the right-angle prisms are bonded together. There is.

  The image light emitted from the combining optical system 500 is enlarged and projected onto the screen SCR by the projection optical device 600.

  In the light source device 710 of this embodiment, based on the luminous efficiencies of the semiconductor lasers 711B, 711G, and 711R of the respective colors and the light outputs of the semiconductor lasers 711B, 711G, and 711R of the respective colors necessary to obtain white light. The number of semiconductor lasers 711B, 711G, and 711R of each color is set. That is, the number of blue semiconductor lasers 711 B having high luminous efficiency is as small as one, and the number of green semiconductor lasers 711 G and red semiconductor lasers 711 R having low luminous efficiency is set as large as three. In addition, a total of seven semiconductor lasers 711 B, 711 G, and 711 R are arranged as described above. Accordingly, it is possible to realize the light source device 710 which is easy to adjust the white balance of the emitted light in addition to the small size.

  Further, in the case of the present embodiment, as described with reference to FIG. 4, even if the diffusion plate 741 common to the blue light LB, the green light LG and the red light LR is used, The diffusion angle distribution of the incident blue light LB and the diffusion angle distribution of the green light LG and the red light LR incident on the diffusion plate 741 with a large incident angle distribution can be equalized. Thus, the lighting device 700 with less occurrence of speckle noise can be realized. In addition, it is not necessary to separately provide different diffusion devices in the light path of each color light, and a compact illumination device 700 can be realized.

  In the light source device 710 of the present embodiment, since the angles formed by a plurality of straight lines m connecting the light emission centers of two adjacent semiconductor lasers 711B, 711G, 711R are equal to each other, the occupied area of the light source unit 750 is reduced. be able to. The green semiconductor laser 711G and the red semiconductor laser 711R are disposed on the holding member 712 so as to surround the blue semiconductor laser 711B and to be located on a virtual circle centered on the blue semiconductor laser 711B. Further, the adjacent semiconductor lasers 711B, 711G, and 711R are disposed such that the blue light casing 716B, the green light casing 716G, and the red light casing 716R are in contact with each other. Thus, a compact light source device 710 capable of emitting white light can be realized without using a wavelength conversion element such as a phosphor.

  Furthermore, in the case of the present embodiment, since the anti-reflection film 747 is provided on the first surface 741 a of the diffusion plate 741, the ratio of the blue light LB entering the light transmitting substrate 742 can be increased. Thereby, the diffusion angle distribution of the blue light LB can be further broadened. The second surface 741 b of the diffusion plate 741 may specularly reflect the blue light LB or diffusely reflect the blue light LB. In the case of diffusely reflecting the blue light LB, the second surface 741b of the diffusion plate 741 may be provided with the same diffusion structure as that on the first surface 741a side. In this case, since diffusion occurs three times while the blue light LB passes through the diffusion plate 741, the diffusion angle distribution of the blue light LB can be further broadened.

  The projector 10 according to the present embodiment includes the illumination device 700 described above, so that the projector 10 is small in size, and can project an image with less speckle noise.

Second Embodiment
Hereinafter, a second embodiment of the present invention will be described with reference to FIG.
The configuration of the projector of the second embodiment is substantially the same as that of the first embodiment, and the configuration of the illumination device is different from that of the first embodiment. Therefore, the description of the entire projector is omitted, and only different parts will be described.
FIG. 8 is a schematic configuration diagram of a projector of the present embodiment.
In FIG. 8, the same components as in FIG. 1 used in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

  As shown in FIG. 8, the projector 15 includes an illumination device 705, a color separation light guide optical system 200, a red light light modulation device 400R, a green light light modulation device 400G, and a blue light light modulation device 400B. , A synthetic optical system 500, and a projection optical device 600.

  The illumination device 705 includes a light source device 710, an afocal optical system 723, a polarization separation element 760, a retardation plate 770, a condensing optical system 725, a diffusion device 740 (diffusion unit), and an integrator optical system 780. And. Among the above components, the configurations of the light source device 710, the diffusion device 740, and the integrator optical system 780 are the same as those in the first embodiment, and the description thereof will be omitted.

  In the illumination device 700, the diffusion device 740, the focusing optical system 725, the retardation plate 770, the polarization separation element 760, and the integrator optical system 780 are provided on the optical axis AX0. The light source device 710, the afocal optical system 723 and the polarization separation element 760 are provided on the optical axis AX1. In the first embodiment, the diffusion device 740 is disposed such that the diffusion plate 741 makes an angle of 45 ° with each of the optical axis AX0 and the optical axis AX1. On the other hand, in the present embodiment, the diffusion device 740 is disposed such that the diffusion plate 741 is perpendicular to the optical axis AX0.

  The afocal optical system 723 is provided downstream of the light source device 710. The afocal optical system 723 reduces the beam diameter of the light LW emitted from the light source device 710. The afocal optical system 723 includes a convex lens 724 and a concave lens 726.

  The light LW emitted from the afocal optical system 723 enters the polarization separation element 760. The polarization separation element 760 is disposed at an angle of 45 ° with respect to each of the optical axis AX0 and the optical axis AX1. The polarization separation element 760 has a polarization separation function of separating light incident on the polarization separation element 760 into an S-polarization component and a P-polarization component with respect to the polarization separation element 760. Specifically, the polarization separation element 760 reflects S-polarized light and transmits P-polarized light. In the case of this embodiment, the light source device 710 is set to emit s-polarized light, and the s-polarized light is reflected by the polarization separation element 760 and travels toward the retardation plate 770.

  The retardation plate 770 is composed of a 1⁄4 wavelength plate disposed in the optical path between the polarization separation element 760 and the diffusion device 740. The S-polarized light LWs reflected by the polarization separation element 760 is converted into, for example, clockwise circularly-polarized light LWc by transmitting through the retardation plate 770, and then enters the condensing optical system 725.

  The condensing optical system 725 condenses the light LWc emitted from the retardation plate 770 on a predetermined condensing position, specifically, on the diffusion plate 741 of the diffusion device 740. The condensing optical system 725 is composed of one convex lens 728. The condensing optical system 725 may be configured of a plurality of lenses. The condensing optical system 725 also serves as a pickup optical system that receives the light reflected by the diffusion plate 741.

  The clockwise circularly polarized light LWc incident on the diffusion plate 741 is converted into counterclockwise circularly polarized light by being reflected by the diffusion plate 741. The left-handed circularly polarized light is converted into P-polarized light LWp by passing through the retardation plate 770. The P-polarized light LWp passes through the polarization separation element 760 and enters the integrator optical system 780. In the present embodiment, it is necessary to prevent the polarization state of the light traveling on the optical path from the diffuser plate 741 to the polarization separation element 760 from being disturbed. The reason is that, when the light whose polarization state is disturbed becomes S-polarized light and enters the polarization separation element 760, it is reflected by the polarization separation element 760 and returns to the light source device 710 side.

  Also in the present embodiment, the projector 15 according to the first embodiment can realize a compact illumination device 705 with less generation of speckle noise and excellent white balance, and can project an image with less speckle noise. The same effect is obtained.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the present invention.
For example, in the above embodiment, the light source device including one blue semiconductor laser, three green semiconductor lasers, and three red semiconductor lasers has been exemplified, but the number of semiconductor lasers is not limited to this. . For example, the light source device may include a plurality of blue semiconductor lasers. In that case, the plurality of green semiconductor lasers and the plurality of red semiconductor lasers may be provided in rotational symmetry around the central axis of the entire light beam composed of the plurality of blue lights emitted from the plurality of blue semiconductor lasers.

  Furthermore, the light source device may be provided with semiconductor lasers of at least two colors such as blue and red.

  Although the example provided with the diffusion plate which was made rotatable by the motor was mentioned as a spreading | diffusion apparatus in the said embodiment, the fixed diffusion plate which does not have a motor may be used. Further, the diffusion device may have a configuration of swinging or vibrating the diffusion plate, for example, instead of rotating the diffusion plate.

  In addition, the number, arrangement, shape, material, dimensions, and the like of the respective components of the light source device, the lighting device, and the projector exemplified in the above embodiment can be appropriately changed.

  Although the projector including the three light modulation devices is illustrated in the above embodiment, it is also possible to apply to a projector which displays a color image by one light modulation device. In addition, a digital mirror device may be used as the light modulation device.

  Moreover, although the example which applies the illuminating device which concerns on this invention to a projector was shown in the said embodiment, it is not restricted to this. The lighting device according to the invention can also be applied to lighting devices such as automotive headlights.

  10, 15: Projector, 400B: Light modulator for blue light, 400G: Light modulator for green light, 400R: Light modulator for red light, 600: Projection optical device, 700, 705: Lighting device, 710: Light source device 711 B: semiconductor laser for blue light (first light emitting device), 711 G: semiconductor laser for green light (second light emitting device), 711 R: semiconductor laser for red light (third light emitting device), 715 B: blue light Semiconductor laser chip (first light emitting element), 715 G: semiconductor laser chip for green light (second light emitting element), 715 R: semiconductor laser chip for red light (third light emitting element), 720, 725: condensing Optical system 740: diffusion device (diffusion portion) 741: diffusion plate 742: translucent substrate 745: motor (rotational portion) 747: anti-reflection film 750: light source .

Claims (8)

A first light emitting device for emitting a first light having a first wavelength; and a second light emitting device for emitting a second light having a second wavelength different from the first wavelength. A light source unit that emits light including the first light and the second light;
A condensing optical system that condenses the light emitted from the light source unit at a predetermined condensing position;
A diffuser disposed at the predetermined condensing position and diffusing the light emitted from the condensing optical system;
Equipped with
The lighting device, wherein, in the diffusion unit, the diffusion characteristics for the first light and the diffusion characteristics for the second light are different from each other. The diffusion unit includes a translucent substrate having a first surface on which light emitted from the condensing optical system is incident, and a second surface different from the first surface.
The first surface transmits and diffuses the first light, and reflects and diffuses the second light,
The lighting device according to claim 1, wherein the second surface reflects the first light. A third light emitting device emitting a third light having a third wavelength different from the first wavelength and the second wavelength;
Equipped with
The first light, the second light and the third light are emitted in a first direction,
The number of second light emitting devices is greater than the number of first light emitting devices,
The second light emitting device is provided in rotational symmetry around a central axis of the first light so as to surround the first light emitting device.
The number of third light emitting devices is greater than the number of first light emitting devices,
The lighting device according to claim 2, wherein the third light emitting device is provided in rotational symmetry around the central axis of the first light so as to surround the first light emitting device. The diffusion unit has a diffusion characteristic for the first light and a diffusion characteristic for the third light, which are different from each other.
The lighting device according to claim 3, wherein the first light reflects and diffuses the third light. The first light is blue,
The second light is green,
The third light is red,
5. The light source unit according to claim 3, wherein the light source unit includes one of the first light emitting devices, three of the second light emitting devices, and three of the third light emitting devices. Lighting device as described.   The said 1st surface is an illuminating device as described in any one of the Claims 2-5 provided with the anti-reflective film which prevents reflection of said 1st light.   The diffusion unit includes a diffusion plate which is irradiated with the light condensed by the condensing optical system and diffuses the light, and a rotating unit which rotates the diffusion plate. Item 7. A lighting device according to any one of Items 6. A lighting device according to any one of claims 1 to 7;
A light modulation device that forms image light by modulating light from the lighting device according to image information;
A projection optical device for projecting the image light;
Equipped with a projector.

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