JP2018120025A - Lighting system and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting system that can reduce optical loss, and to provide a projector that includes the lighting system.SOLUTION: A lighting system comprises a light source device, a light forming optical system, and a diffusion element. The light source device includes a first light emitting element that emits a first light beam and emits light including the first light beam. The light is made incident on the light forming optical system. The light forming optical system includes a first lens on which the first light beam is made incident. The light transmitting through the light forming optical system is made incident on the diffusion element. A lighting area formed by the light on the diffusion element has first edges that are recessed toward the inside of the lighting area. The first lens has a first rotational asymmetrical free-form surface.SELECTED DRAWING: Figure 4

Description

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

  2. Description of the Related Art In recent years, a light source device that generates fluorescence by making excitation light emitted from a laser array incident on a phosphor layer in a condensed state is known (for example, see Patent Document 1 below). In a projector using this light source device, the first and second integrator lens arrays are used to irradiate the light modulation device that is the illuminated region with fluorescence.

  In addition, in a projector, a technique is known in which excitation light emitted from a laser array is incident on a phosphor layer using two multi-lens arrays and a condenser lens to generate fluorescence (for example, the following) Patent Document 2). Due to the action of the two multi-lens arrays and the condenser lens, the spot of the excitation light on the phosphor layer becomes rectangular.

  Incidentally, since the image forming area of the light modulation device is rectangular, it is preferable that the cross-sectional shape of the light that illuminates the light modulation device is rectangular.

JP 2012-108486 A JP 2014-138148 A

  Therefore, the spot of the excitation light on the phosphor layer can be made rectangular by combining the light source device disclosed in Patent Document 1 with the two multi-lens arrays disclosed in Patent Document 2. Conceivable.

Even when the excitation light spot on the phosphor layer is rectangular, the emission region in the phosphor layer is not rectangular but has a shape close to a circle due to diffusion of excitation light and fluorescence inside the phosphor layer. Become.
When illuminating a rectangular illuminated area with a light bundle emitted from such a circular light emitting area, an image of a circular light source is formed on each lens of the second integrator lens array. Since each lens of the second integrator lens array has a rectangular shape, when a circular image is larger than the outer shape of the lens, a part of the circular image is incident on an adjacent lens, so that it deviates outside the illuminated area. Light loss will occur. If the circular image is made small in order to avoid this, the angle of the light beam becomes large and a loss occurs in the optical system at the subsequent stage.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the illuminating device which can reduce a light loss. Another object is to provide a projector including the lighting device.

  According to the first aspect of the present invention, a light source device including a first light emitting element that emits a first light beam, a light shaping optical system including a first lens on which the first light beam is incident, and the light A diffusing element on which light source light including the first light flux that has passed through the shaping optical system is incident, and an illumination area formed on the diffusing element by the light source light is recessed toward the inside of the illumination area An illumination device having a first edge and the first lens having a first rotationally asymmetric free-form surface is provided.

  In the illumination device according to the first aspect, since light is diffused by the diffusing element in the illumination area, the light emitting area spreads outside the illumination area at the first edge. As a result, the light emitting region has a shape in which at least a portion corresponding to the first edge portion is closer to a rectangle than the shape of the illumination region. Therefore, light in the light emitting region can be used efficiently, and light loss can be reduced. Further, since the first lens has the first rotationally asymmetric free-form surface, it is easy to control the shape of the illumination area.

The said 1st aspect WHEREIN: It is preferable that the external shape of the said illumination area | region has a some edge part including the said 1st edge part recessed toward the inner side of the said illumination area | region.
According to this configuration, the light emitting region in the diffusing element can be made closer to a rectangle.

  In the first aspect, it is preferable that the first rotationally asymmetric free-form surface is represented by Expression (1) in which x and y are variables.

  According to this configuration, since the curvature in the x direction and the curvature in the y direction can be designed independently, lens design is facilitated.

In the first aspect, it is preferable that the formula (1) includes at least one term represented by x ^2p y ^2p , where p is a positive integer.
According to this configuration, the size of the spot formed by the first light beam on the diffusing element in the diagonal direction (direction intersecting the x direction and the y direction) can be easily adjusted.

In the first embodiment, in the formula (1), when the h a positive integer, the coefficient of the term of x ^h C _j is preferably different from the coefficient C _j term of y ^h.
According to this configuration, the spot size can be independently adjusted in the x direction and the y direction.

In the first aspect, in the formula (1), the coefficient C _j of the term x ² y ⁴ is preferably different from the coefficient C _j of the term x ⁴ y ² .
According to this configuration, the size of the spot in the diagonal direction can be accurately adjusted in the x direction and the y direction.

In the first aspect, the light source device further includes a second light emitting element that emits second light, and the light shaping optical system includes a second lens on which the second light is incident, and the first lens It is preferable that the lens further includes a lens surface that makes the light and the second light incident on the diffusing element, and the second lens has a second rotationally asymmetric free-form surface.
According to this configuration, when the first light and the second light are used, the light emitting region in the diffusing element can be made close to a rectangle.

In the first aspect, the lens surface is preferably configured such that the chief ray of the first light and the chief ray of the second light are incident on different positions on the diffusing element. .
According to this configuration, an illumination area having a desired shape can be formed by combining the first light and the second light.

In the first aspect, the diffusion element preferably includes a wavelength conversion element.
According to this configuration, the emission region of the fluorescence emitted from the wavelength conversion element can be made closer to a rectangle. Therefore, loss of fluorescent light can be reduced.

  According to the second aspect of the present invention, the illumination device of the first aspect, a light modulation device that generates illumination light by modulating illumination light emitted from the illumination device according to image information, and the image light And a projection optical system for projecting.

  In the projector according to the second aspect, light loss in the illumination device is reduced.

Schematic which shows the optical system of a projector. The figure which shows schematic structure of an illuminating device. The figure which shows the shape of the light emission area | region produced | generated by the rectangular illumination area. The figure which shows the structure of a light shaping optical system and its periphery. The figure which shows the shape of the light emission area | region produced | generated by the pincushion-like illumination area | region. The figure which showed the spot shape of the blue laser beam. The figure which showed another form of the spot shape of a blue laser beam. The figure which showed the shape of each spot which forms the illumination area in a 3rd modification. The figure which showed the shape of each spot which forms the illumination area in a 4th modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

FIG. 1 is a schematic diagram illustrating an optical system of a projector according to the present embodiment.
As shown in FIG. 1, the projector 1 includes an illumination device 100, a color separation light guide optical system 200, a liquid crystal light modulation device 400R, a liquid crystal light modulation device 400G, a liquid crystal light modulation device 400B, and a cross dichroic prism 500. And a projection optical system 600.

  The lighting device 100 includes a first lighting device 101 and a second lighting device 102. The first lighting device 101 emits fluorescent light YL including red light and green light toward the color separation light guide optical system 200. The second illumination device 102 emits the blue light B toward the color separation light guide optical system 200.

  The color separation light guide optical system 200 includes a dichroic mirror 210, a reflection mirror 220, a reflection mirror 230, and a reflection mirror 250. The color separation light guide optical system 200 separates the yellow fluorescent light YL emitted from the first illumination device 101 into red light R and green light G, and supplies the light to the corresponding liquid crystal light modulation device 400R and liquid crystal light modulation device 400G. Light guide. The color separation light guide optical system 200 guides the blue light B emitted from the second illumination device 102 to the liquid crystal light modulation device 400B. The field lens 300R, the field lens 300G, and the field lens 300B are disposed between the color separation light guide optical system 200 and the liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B.

  The dichroic mirror 210 is a dichroic mirror that transmits a red light component and reflects a green light component. The reflection mirror 220 is a mirror that reflects the green light component. The reflection mirror 230 is a mirror that reflects a red light component. The reflection mirror 250 is a reflection mirror that reflects blue light components.

  The red light R that has passed through the dichroic mirror 210 is reflected by the reflecting mirror 230, passes through the field lens 300R, and enters the image forming region of the liquid crystal light modulation device 400R for red light. The green light G reflected by the dichroic mirror 210 is further reflected by the reflection mirror 220, passes through the field lens 300G, and enters the image forming region of the liquid crystal light modulation device 400G for green light. The blue light B reflected by the reflection mirror 250 passes through the field lens 300B and enters the image forming area of the liquid crystal light modulation device 400B for blue light.

The liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B modulate incident color light according to image information, and form a color image corresponding to each color light.
Although not shown, incident-side polarizing plates are respectively disposed on the light incident side of the liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B. An exit-side polarizing plate is disposed on the light exit side of each of the liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B.

  The cross dichroic prism 500 synthesizes each image light emitted from the liquid crystal light modulation device 400R, the liquid crystal light modulation device 400G, and the liquid crystal light modulation device 400B to form a color image. The cross dichroic prism 500 has a substantially square shape in plan view in which four right-angle prisms are bonded together, and a dielectric multilayer film is formed on a substantially X-shaped interface in which the right-angle prisms are bonded together.

  The color image emitted from the cross dichroic prism 500 is enlarged and projected by the projection optical system 600 to form an image on the screen SCR. The projection optical system 600 is composed of a plurality of projection lenses.

Then, the structure of the illuminating device 100 is demonstrated.
FIG. 2 is a diagram illustrating a schematic configuration of the illumination device 100. As shown in FIG. 2, the first illumination device 101 includes a first light source device 10, a light shaping optical system 20, a rotating fluorescent plate 30, a pickup optical system 60, a first lens array 120, and a second lens array. 130, a polarization conversion element 140, and a superimposing lens 150.

The first light source device 10 includes a light source unit 14 and a collimating optical system 15.
The light source unit 14 includes a plurality of semiconductor lasers 11 that emit blue laser light (for example, light having an emission intensity peak of about 445 nm) LB as excitation light. The semiconductor laser 11 may emit blue laser light having a wavelength other than 445 nm, for example, 460 nm.

  In the present embodiment, the plurality of semiconductor lasers 11 are two-dimensionally arranged. The plurality of semiconductor lasers 11 are arranged in a matrix (for example, 5 rows and 5 columns) in a plane perpendicular to the illumination optical axis 100ax. The first light source device 10 emits excitation light KS composed of a plurality of blue laser lights LB. In the present embodiment, the first light source device 10 corresponds to “light source device” in the claims, and the excitation light KS corresponds to “light source light” in the claims.

  The collimating optical system 15 has a plurality of collimating lenses 15a. The plurality of collimating lenses 15a are two-dimensionally arranged. Each of the plurality of collimating lenses 15 a is arranged corresponding to each of the plurality of semiconductor lasers 11. That is, the plurality of collimating lenses 15a are arranged in a matrix (for example, 5 rows and 5 columns).

  Each of the plurality of collimating lenses 15a collimates the corresponding blue laser light LB. In the present embodiment, the excitation light KS emitted from the first light source device 10 enters the light shaping optical system 20 as parallel light, and enters the rotating fluorescent plate 30 via the light shaping optical system 20. The configuration of the optical shaping optical system 20 will be described later.

  The rotating fluorescent plate 30 includes a motor 50, a base material 40, a dichroic layer 41, and a phosphor layer 42. The rotating fluorescent plate 30 emits fluorescent light YL toward the side opposite to the side on which the excitation light KS made of blue light is incident. That is, the rotating fluorescent plate 30 is a transmissive rotating fluorescent plate.

  The base material 40 is comprised from the material which has translucency, such as glass, quartz, sapphire, for example. The base material 40 can be rotated around a rotation axis by a motor 50. The base material 40 is a plate having a circular planar shape.

  The phosphor layer 42 includes an inorganic phosphor material whose planar shape is annular. As the phosphor layer 42, for example, a phosphor layer in which phosphor particles emitting yellow fluorescent light are dispersed in an inorganic binder such as alumina, or a phosphor layer in which phosphor particles are sintered without using a binder. Is used. The phosphor layer 42 is provided around the rotation axis on the one surface 40 a side of the substrate 40. In the present embodiment, the phosphor layer 42 corresponds to a “wavelength conversion element” and a “diffusion element” in the claims.

  Since the excitation light KS made of laser light is incident on the rotating fluorescent plate 30, heat is generated in the rotating fluorescent plate 30. In the present embodiment, the incident position of the excitation light KS on the rotating fluorescent plate 30 is temporally changed by rotating the substrate 40. As a result, the same portion of the rotating fluorescent plate 30 is always irradiated with the excitation light KS, and the rotating fluorescent plate 30 is locally heated and deteriorated.

  Hereinafter, an area where the excitation light KS is incident on the surface of the phosphor layer 42 is referred to as an illumination area, and an area where the fluorescent light YL generated by the excitation light KS incident on the illumination area is emitted is referred to as an emission area. Call it.

  Since the excitation light KS incident on the phosphor layer 42 travels while being refracted and reflected inside the phosphor layer 42, the excitation light KS is also irradiated to the phosphor particles arranged outside the illumination region in plan view. Is done. Further, the fluorescent light YL emitted from the phosphor particles also travels while being refracted and reflected inside the phosphor layer 42. As described above, the light emitting region of the phosphor layer 42 extends outside the illumination region by the excitation light KS, and thus the light emitting region is larger than the illumination region.

  The fluorescent light YL emitted from the light emitting region enters the pickup optical system 60. The pickup optical system 60 is composed of, for example, two pickup lenses 60a and 60b. The pickup optical system 60 collimates the fluorescent light YL and guides it to the first lens array 120.

  The first lens array 120 has a plurality of first small lenses 122 for dividing the fluorescent light YL into a plurality of partial light beams. The plurality of first small lenses 122 are arranged in a matrix in a plane orthogonal to the illumination optical axis 100ax. In the present embodiment, the shape of each of the first small lenses 122 is substantially similar (rectangular) to the shape of the image forming regions of the liquid crystal light modulation device 400R and the liquid crystal light modulation device 400G. Therefore, the overall shape of the first lens array 120 is also rectangular. Based on such a configuration, the partial light beams emitted from the first lens array 120 are efficiently incident on the image forming regions of the liquid crystal light modulation device 400R and the liquid crystal light modulation device 400G, respectively.

  The second lens array 130 has a plurality of second small lenses 132. Each of the plurality of second small lenses 132 has the same rectangular shape as each of the plurality of first small lenses 122. The first small lens 122 and the second small lens 132 are in a one-to-one correspondence with each other, and the plurality of second small lenses 132 are arranged in a matrix in a plane orthogonal to the illumination optical axis 100ax. Therefore, the overall shape of the second lens array 130 is also rectangular.

  The second lens array 130 cooperates with the subsequent superimposing lens 150 and the field lens 300R or the field lens 300G to convert the image of the first small lens 122 of the first lens array 120 into the liquid crystal light modulator 400R or the liquid crystal light modulator. It has a function of forming an image in the vicinity of the image forming area of the apparatus 400G.

Here, the case where the illumination area SA by the excitation light KS is rectangular is described as a comparative example. FIG. 3 is a simulation result showing the shape of the light emitting area HA when the shape of the illumination area SA is rectangular. In FIG. 3, the illumination area SA is indicated by a broken line.
As shown in FIG. 3, the light emitting area HA generated by the rectangular illumination area SA has no rectangular corners and has a shape in which the central part of each side bulges outward. Hereinafter, the shape in which the center part of each side bulges outside is referred to as a barrel shape.

  The shape of the fluorescent light YL emitted from the barrel-shaped light emitting area HA is substantially circular. In general, the light incident surface of the first lens array 120 has a rectangular shape. When the fluorescent light YL having a circular luminous flux enters the first lens array 120 having a rectangular light incident surface, the circular fluorescent light YL is cut out into a rectangular shape, and light loss occurs.

  On the other hand, it is also conceivable to reduce the light loss by making the size of the first lens array 120 and the second lens array 130 (the size of the long side of the rectangle) larger than the beam diameter of the fluorescent light YL. However, in this case, with the increase in size of the first lens array 120 and the second lens array 130, a new problem arises that the illumination device itself also increases in size.

  In the present embodiment, a plurality of images of the light emitting area HA of the rotating fluorescent plate 30 are formed on the lens surface of the second lens array 130. The image serves as a secondary light source.

  In the present embodiment, the lens surface of the second lens array 130 (the surface of the second small lens 132) and the light emitting area HA of the rotating fluorescent plate 30 are substantially conjugate with each other. Therefore, an image (secondary light source image) of the light emitting area HA of the rotating fluorescent plate 30 is formed on the lens surface of the second lens array 130 (the surface of the second small lens 132).

  The shape of the secondary light source image is the same as the shape of the light emitting area HA. Therefore, when the light emitting area HA has a barrel shape, the secondary light source image also has a barrel shape. In the present embodiment, the planar shape of the second small lens 132 is a rectangle. Therefore, the barrel-shaped secondary light source image is more likely to protrude from the rectangular second small lens 132 as compared with the rectangular secondary light development, and there is a possibility that the utilization efficiency of the fluorescent light YL is reduced. there were.

  In order to solve these problems, in the first illumination device 101 of the present embodiment, the shape of the illumination area SA of the excitation light KS is adjusted using the light shaping optical system 20, and the shape of the light emission area HA is substantially rectangular. It was made to become.

Hereinafter, a specific configuration of the light shaping optical system 20 will be described.
FIG. 4 is a diagram showing the configuration of the optical shaping optical system 20 and its periphery. For convenience of explanation, FIG. 4 shows only the phosphor layer 42 that is the object to be illuminated with the excitation light KS in the rotating fluorescent plate 30.
As shown in FIG. 4, the light shaping optical system 20 is provided on the light emission side of the first light source device 10, and the excitation light KS emitted from the first light source device 10 is incident thereon.

  In the present embodiment, the plurality of semiconductor lasers 11 constituting the first light source device 10 include a first semiconductor laser 11a and a second semiconductor laser 11b. Hereinafter, the blue laser light LB emitted from the first semiconductor laser 11a is referred to as blue laser light LB1, and the blue laser light LB emitted from the second semiconductor laser 11b is referred to as blue laser light LB2.

  The first light source device 10 corresponds to the “light source device” in the claims, the first semiconductor laser 11a corresponds to the “first light emitting element” in the claims, and the second semiconductor laser 11b corresponds to the patent. This corresponds to the “second light emitting element” in the claims.

  Further, the blue laser light LB1 corresponds to a “first light beam” in the claims, and the blue laser light LB2 corresponds to a “second light beam” in the claims.

The optical shaping optical system 20 includes a lens member 20a having a plano-convex lens shape, and a plurality of lenses 21 arranged in an array on the flat surface side of the lens member 20a. The lens member 20a has a lens surface 20a1 on the light incident surface side. The lens surface 20a1 has a function of causing each blue laser beam LB to enter (condense) the phosphor layer 42. Each of the plurality of lenses 21 may be formed integrally with the lens member 20a, or may be configured separately.
Each of the plurality of lenses 21 is provided corresponding to each of the plurality of semiconductor lasers 11. That is, the plurality of lenses 21 are arranged in a matrix (for example, 5 rows and 5 columns in FIG. 4).

  In the present embodiment, the light shaping optical system 20 is configured to illuminate the blue laser light LB emitted from each of the plurality of semiconductor lasers 11 in a state where a predetermined region of the phosphor layer 42 is superimposed. The blue laser beam LB being superimposed means a state in which the spots SP of the blue laser beams LB are substantially overlapped.

  An illumination area SA is formed on the phosphor layer 42 by overlapping the spots SP of the blue laser beams LB. Therefore, in the present embodiment, the shape of the illumination area SA substantially matches the shape of the spot SP of each blue laser beam LB.

  The plurality of lenses 21 includes a first lens 21a and a second lens 21b. The first lens 21a is provided corresponding to the first semiconductor laser 11a, and the second lens 21b is provided corresponding to the second semiconductor laser 11b.

  Therefore, the blue laser light LB1 emitted from the first semiconductor laser 11a is incident on the first lens 21a, and the blue laser light LB2 emitted from the second semiconductor laser 11b is incident on the second lens 21b.

  In the present embodiment, each of the plurality of lenses 21 is a free-form surface lens having a free-form surface. Each of the plurality of lenses 21 forms a spot SP that the corresponding blue laser beam LB forms on the phosphor layer 42. By using a free-form surface lens in this way, the shape of the spot SP can be easily controlled.

Hereinafter, the structure of the plurality of lenses 21 will be described using the first lens 21a as an example. The first lens 21a has a first free curved surface 22a defined by a polynomial having x and y as variables. The first free curved surface 22a is a rotationally asymmetric free curved surface. That is, in the present embodiment, the first free-form surface 22a corresponds to a “first rotationally asymmetric free-form surface” in the claims.
Specifically, the first free-form surface 22a is represented by the following formula (1). In the formula (1), an orthogonal coordinate system having a z-axis in a direction parallel to the optical axis of the first lens 21a is used.

In the above formula (1), m and n are integers of 0 or more, k is a conic constant, c is a curvature, c _j is a coefficient of x ^m y ⁿ , and j = [(m + n) ² + M + 3n] / 2 + 1, S = [(m ₁ + n ₁ ) ² + m ₁ + 3n ₁ ] / 2 + 1, r = (x ² + y ² ) ^1/2 . Note that m ₁ and n ₁ are upper limits of m and n, respectively.

The first free-form surface 22a of the first lens 21a includes at least one term represented by x ^2p y ^2p, where p is a positive integer. Hereinafter, “including at least one term represented by x ^2p y ^2p ” may be referred to as a first condition.

When the first condition is satisfied, the polynomial includes at least one of the terms x ² y ² , x ⁴ y ⁴ , x ⁶ y ⁶ .

  According to the first free-form surface 22a that satisfies such a first condition, the size of the spot SP formed by the blue laser beam LB1 on the phosphor layer 42 in the diagonal direction (direction intersecting the x direction and the y direction). Can be adjusted easily. Thereby, the shape of the spot SP can be shaped into a shape in which four edges are recessed inward. Hereinafter, a shape in which four edges are recessed inward is referred to as a bobbin shape.

In the first lens 21a (first free-form surface 22a), when the h a positive integer, the coefficient _{C j} terms of ^{x h} is different from the coefficient _{C j} term of ^{y h.} Hereinafter sometimes referred to be "coefficient C _j terms of x ^h is different from the coefficient C _j in the section y ^h" and the second condition.

  According to the first free-form surface 22a satisfying the second condition, the size of the spot SP formed by the blue laser light LB1 on the phosphor layer 42 can be adjusted independently in the x direction and the y direction.

In the first lens 21a (first free-form surface 22a), the coefficient C _j of the term x ² y ⁴ is different from the coefficient C _j of the term x ⁴ y ² . Hereinafter, “the coefficient C _j of the term of x ² y ⁴ is different from the coefficient C _j of the term of x ⁴ y ² ” may be referred to as a third condition.

  According to the first free-form surface 22a that satisfies the third condition, the size of the spot SP in the diagonal direction can be accurately adjusted in the x direction and the y direction.

  As described above, the first lens 21a has the first free-form surface 22a that satisfies the first to third conditions, and therefore forms a pincushion spot SP on the phosphor layer 42.

  Similarly, the second lens 21b has a second free curved surface 22b made of a rotationally asymmetric free curved surface. The second free-form surface 22b is defined by the polynomial of the above formula (1), and this polynomial satisfies the first to third conditions described above. The blue laser beam LB2 emitted from the second lens 21b having the second free-form surface 22b forms a pincushion spot SP on the phosphor layer 42, like the blue laser beam LB1. In the present embodiment, the second free-form surface 22b corresponds to a “second rotationally asymmetric free-form surface” in the claims.

  Similar to the first lens 21a and the second lens 21b described above, the remainder of the plurality of lenses 21 has a free-form surface defined by a polynomial that satisfies the first to third conditions. The blue laser light LB emitted from each lens 21 forms a pincushion-shaped spot SP on the phosphor layer 42.

  Further, the spots SP formed on the phosphor layer 42 are superimposed on each other by the lens surface 20a1.

  As described above, the light shaping optical system 20 of the present embodiment forms the pincushion-like illumination area SA on the phosphor layer 42 by superimposing the spots SP of the blue laser beams LB on the phosphor layer 42. .

FIG. 5 is a diagram showing a simulation result regarding the shape of the light emitting area HA generated by the pincushion-shaped illumination area SA. In FIG. 5, the illumination area SA is indicated by a broken line.
As shown in FIG. 5, the illumination area SA has a so-called pincushion shape having a plurality of edges SA1 to SA4 that are recessed toward the inside of the illumination area SA. In the present embodiment, the edge SA1 corresponds to a “first edge” in the claims.

As shown in FIG. 5, the light emitting area HA formed by the pincushion-shaped illumination area SA has a substantially rectangular shape.
Specifically, portions corresponding to the plurality of edge portions SA1 to SA4 recessed inward in the illumination area SA bulge outward, so that the shape of the light emitting area HA is substantially rectangular as a whole. The luminous flux shape of the fluorescent light YL emitted from the rectangular light emitting area HA is rectangular. Since the planar shape of the light incident surface of the first lens array 120 is rectangular, it is possible to capture fluorescence more efficiently than when the shape of the light beam of the fluorescent light YL is circular.

  The luminous flux shape of the fluorescent light YL may be set so as to be substantially similar to the planar shape of the light incident surface of the first lens array 120. For that purpose, for example, by appropriately adjusting the magnification of the pickup optical system 60, the fluorescent light YL can be efficiently taken into the first lens array 120 to further improve the light utilization efficiency.

  An image of the light emitting area HA, that is, a substantially rectangular secondary light source image is formed on the lens surface of the second lens array 130 (the surface of the second small lens 132). When the shape of the secondary light source image is rectangular, the secondary light source image is difficult to protrude from the second small lens 132. Therefore, the fluorescent light YL can be used efficiently.

  Further, in the present embodiment, the illumination area SA is configured by overlapping a plurality of spots SP, and thus has a highly uniform illuminance distribution. Therefore, even if the outputs of the plurality of semiconductor lasers 11 (the amount of blue laser light LB) vary, the phosphor layer 42 can be illuminated uniformly.

  Therefore, according to the first illumination device 101 of the present embodiment, the loss of the fluorescent light YL can be reduced.

  Returning to FIG. 2, the polarization conversion element 140 converts each partial light beam (fluorescence light YL) divided by the first lens array 120 into linearly polarized light having the same polarization direction.

  The superimposing lens 150 condenses the partial light beams emitted from the polarization conversion element 140 and superimposes them on the respective image forming regions of the liquid crystal light modulation device 400R and the liquid crystal light modulation device 400G or in the vicinity thereof. The first lens array 120, the second lens array 130, and the superimposing lens 150 constitute an integrator optical system that makes the in-plane light intensity distribution of the fluorescent light YL emitted from the rotating fluorescent plate 30 uniform.

  On the other hand, the second illumination device 102 includes a second light source device 710, a condensing optical system 720, a scattering plate 730, a pickup optical system 731, a lens integrator optical system 740, and a superimposing lens 760.

  Similar to the first light source device 10, the second light source device 710 includes a light source unit 14 and a collimating optical system 15. The light source unit 14 includes a semiconductor laser 11 that emits blue laser light LB. The number of semiconductor lasers 11 constituting the light source unit 14 may be one or more. Based on such a configuration, the second light source device 710 emits blue light B made of laser light.

  The condensing optical system 720 includes a first lens 722 and a second lens 724. As a whole, the condensing optical system 720 causes the blue light B to be incident on the scattering plate 730 in a substantially condensed state. The first lens 722 and the second lens 724 are convex lenses.

  The scattering plate 730 scatters the blue light B from the second light source device 710 with a predetermined scattering degree, and has a light distribution similar to fluorescence (red light and green light emitted from the rotating fluorescent plate 30). And As the scattering plate 730, for example, polished glass made of optical glass can be used.

  The pickup optical system 731 includes lenses 732 and 733. Each of the lenses 732 and 733 is a convex lens. The pickup optical system 731 collimates the blue light B scattered by the scattering plate 730 and makes it incident on the lens integrator optical system 740.

  The lens integrator optical system 740 includes lens arrays 750 and 751. The lens array 750 includes a plurality of small lenses 750a for dividing the blue light B into a plurality of partial light beams. The lens array 751 has a plurality of small lenses 751 a corresponding to the plurality of small lenses 750 a of the lens array 750. The lens array 751 forms an image of the small lens 750a of the lens array 750 together with the superimposing lens 760 in the subsequent stage in the image forming region of the liquid crystal light modulation device 400B or in the vicinity thereof.

  In the present embodiment, the blue light B emitted from the second illumination device 102 is reflected by the reflection mirror 250, passes through the field lens 300B, and enters the image forming region of the blue light liquid crystal light modulation device 400B.

  As described above, according to the first illumination device 101 of the present embodiment, the illumination area SA of the fluorescent light YL can be made closer to a rectangle by making the illumination area SA a pincushion shape. Thereby, high light utilization efficiency is realizable because the 1st lens array 120 takes in fluorescence light YL efficiently.

  According to the projector 1 of the present embodiment, since the illumination device 100 including the first illumination device 101 is provided, a bright color image can be displayed on the screen SCR.

  In the above embodiment, the pincushion-like illumination area SA is formed on the phosphor layer 42. However, the present invention is not limited to this. For example, the pincushion-like illumination area SA is used as the diffusion plate. It may be formed on top. In this case, diffused light having a substantially rectangular cross section is obtained.

  Moreover, in the said embodiment, although the structure which condenses blue laser beam LB on the fluorescent substance layer 42 by the lens member 20a (lens surface 20a1) of the optical shaping optical system 20 was mentioned as an example, this invention is not limited to this. . For example, instead of the lens member 20a, a lens surface having a condensing function may be provided on the light incident surface side of each lens 21.

  Alternatively, the free curved surface of each lens 21 may have a deflecting function for deflecting the traveling direction of light. In this way, each lens 21 can change the traveling direction of the blue laser light LB to be condensed on the phosphor layer 42, so that the lens member 20a is not necessary.

In addition, this invention is not limited to the content of the said embodiment and modification, In the range which does not deviate from the main point of invention, it can change suitably.
For example, in the above embodiment, the case where the illumination area SA is formed by superimposing each of the plurality of blue laser beams LB on the phosphor layer 42 is described as an example, but the present invention is not limited to this. Hereinafter, a modified example in the case of forming the illumination area SA will be described.

(First modification)
In the above-described embodiment, the case where the illumination area SA is formed by superimposing a plurality of spool-shaped spots SP is described as an example, but the present invention is not limited to this. For example, the first light source device 10 is composed of one semiconductor laser 11 (for example, the first semiconductor laser 11a), and only one spot of the blue laser light LB1 emitted from the first semiconductor laser 11a is used. A bobbin-shaped illumination area SA may be formed. In this case, the light shaping optical system 20 includes only the first lens 21a.

(Second modification)
The first light source device 10 may be composed of two semiconductor lasers 11 (for example, a first semiconductor laser 11a and a second semiconductor laser 11b). In this case, the light shaping optical system 20 includes only the first lens 21a and the second lens 21b.

  In this modification, the light shaping optical system 20 (lens surface 20a1) is configured to cause the spot SP1 of the blue laser light LB1 and the spot SP2 of the blue laser light LB2 to be incident on different positions on the phosphor layer 42. . That is, the spots SP1 and SP2 do not overlap each other on the phosphor layer 42.

FIG. 6 is a diagram showing spot shapes of the blue laser beams LB1 and LB2 according to the second modification.
As shown in FIG. 6, each of the spots SP1 and SP2 of the blue laser beams LB1 and LB2 has a shape in which the pincushion-like illumination area SA is halved, and the shapes of the spots are axisymmetric. In this modification, the free-form optical system 20 is designed with the free curved surfaces of the first lens 21a and the second lens 21b so as to form the spots SP1 and SP2 each having a half-pound shape. .

  By combining the spots SP1 and SP2 having such a shape, a bobbin-shaped illumination area SA can be formed on the phosphor layer.

FIG. 7 is a diagram showing another form of the spot shape of the blue laser beams LB1 and LB2.
As shown in FIG. 7, the spots SP <b> 1 and SP <b> 2 of the blue laser beams LB <b> 1 and LB <b> 2 have an elliptical shape and are arranged on the phosphor layer 42 so that their long axes intersect each other. The illumination area SB is formed on the phosphor layer 42 by synthesizing the spots SP1 and SP2. The shape of the illumination area SB is substantially a bobbin shape having four edge portions SB1 to SB4 recessed inward.

  In this modification, the light shaping optical system 20 is designed with the free curved surfaces of the first lens 21a and the second lens 21b so as to form the elliptical spots SP1 and SP2.

  In the second modification, the example in which the pincushion-like illumination areas SA and SB are formed by combining two spots that are not the pincushion-like shape has been described, but the pincushion-like illumination using three or more spots that do not overlap each other. A region may be formed.

(Third modification)
FIG. 8 is a diagram showing the shape of each spot forming the illumination area SA in this modification. In order to simplify the description in this modification, for example, a case where the illumination area SA is formed with three spots will be described as an example.

  As shown in FIG. 8, the illumination area SA of the present modification is formed in a pincushion shape by combining three spots SP1 to SP3. Each of the spots SP1 and SP2 is formed by halving the pincushion shape. The spot SP3 has the same pincushion shape as the illumination area SA.

As described above, in this modification, the spots SP1 to SP3 forming the illumination area SA have various shapes.
Also in this modification, the pincushion-shaped illumination area SA can be formed by combining the spots SP1 to SP3.

(Fourth modification)
In the above embodiment, as the pincushion-shaped illumination area SA, the edge parts SA1 to SA4 are curved, but the shape of the illumination area is not limited to this.

FIG. 9 is a diagram showing the shape of each spot forming the illumination area SC in this modification.
As shown in FIG. 9, the illumination area SC of the present modification includes a first illumination area S1, a second illumination area S2, a third illumination area S3, a fourth illumination area S4, and a fifth illumination area S5. Have

  For example, the first illumination region S1 is formed by combining a plurality of spots, and the overall shape is substantially square. The second illumination area S2, the third illumination area S3, the fourth illumination area S4, and the fifth illumination area S5 are each composed of one spot, and each shape is substantially square.

  The second illumination region S2, the third illumination region S3, the fourth illumination region S4, and the fifth illumination region S5 are arranged so as to partially overlap the four corners (corner portions) of the square first illumination region S1. . Therefore, the illumination area SC has a shape in which the outer shape of the first illumination area S1 is recessed inward with respect to the outer shapes of the second illumination area S2, the third illumination area S3, the fourth illumination area S4, and the fifth illumination area S5. ing. That is, the illumination area SC shown in FIG. 9 has a shape in which the four edge portions SC1 to SC4 are recessed inwardly in a step shape.

  As described above, even in the illumination area SC where the edges SC1 to SC4 are stepped, the light emission area HA of the fluorescent light YL can be rectangular.

  In the above-described embodiment, the projector 1 including the three liquid crystal light modulation devices 400R, 400G, and 400B is illustrated. However, the projector 1 can be applied to a projector that displays a color image with one liquid crystal light modulation device. A digital mirror device may be used as the light modulation device.

  In the above embodiment, an example in which the lighting device according to the present invention is mounted on a projector has been shown, but the present invention is not limited to this. The lighting device according to the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

  DESCRIPTION OF SYMBOLS 1 ... Projector, 10 ... 1st light source device, 11a ... 1st semiconductor laser, 11b ... 2nd semiconductor laser, 20 ... Light shaping optical system, 21a ... 1st lens, 21b ... 2nd lens, 22a ... First free-form surface (first rotationally asymmetric free-form surface), 22b ... Second free-form surface (second rotationally asymmetric free-form surface), 42 ... phosphor layer, 101 ... first illumination device, 102 ... second illumination 400B, 400G, 400R ... liquid crystal light modulator, 600 ... projection optical system, 710 ... second light source device, LB1 ... blue laser light (first light flux), LB2 ... blue laser light (second light flux), SA, SB, SC ... illumination area, SA1, SA2, SA3, SA4 ... edge, SB1, SB2, SB3, SB4 ... edge, SC1, SC2, SC3, SC4 ... edge, KS ... excitation light (light source light) .

Claims (10)

A light source device that includes a first light emitting element that emits a first light flux, and that emits light that includes the first light flux;
A light shaping optical system including the first lens on which the first light flux is incident and the light is incident;
A diffusion element on which the light transmitted through the light shaping optical system is incident,
The illumination area that the light forms on the diffusing element has a first edge that is recessed toward the inside of the illumination area;
The first lens has a first rotationally asymmetric free-form surface. The illuminating device according to claim 1, wherein an outer shape of the illumination area has a plurality of edges including the first edge that are recessed toward the inside of the illumination area. The lighting device according to claim 1, wherein the first rotationally asymmetric free-form surface is represented by an expression (1) having x and y as variables.
4. The lighting device according to claim 3, wherein, in the formula (1), when p is a positive integer, at least one term represented by x ^2p y ^2p is included. In the formula (1), when the h a positive integer, the coefficient of the term of x ^h C _j lighting apparatus according to claim 3 or 4 is different from the coefficient C _j term of y ^h. 5. The lighting device according to claim 3, wherein, in the formula (1), a coefficient C _j of a term of x ² y ⁴ is different from a coefficient C _j of a term of x ⁴ y ² . The light source device further includes a second light emitting element that emits a second light flux,
The light shaping optical system further includes a second lens on which the second light beam is incident, and a lens surface on which the first light beam and the second light beam are incident on the diffusing element,
The lighting device according to claim 1, wherein the second lens has a second rotationally asymmetric free-form surface. The illumination device according to claim 7, wherein the lens surface is configured such that the principal ray of the first light flux and the principal ray of the second light flux are incident on different positions on the diffusing element. The illuminating device according to any one of claims 1 to 8, wherein the diffusion element includes a wavelength conversion element. The lighting device according to any one of claims 1 to 9,
A light modulation device for generating image light by modulating illumination light emitted from the illumination device according to image information;
A projection optical system that projects the image light.