JP2017015966A - Light source device and projector - Google Patents

Abstract

A light source device and a projector capable of increasing a diffusion angle while suppressing loss of light are provided. A first light emitting element, a rod provided on the optical path of the first light emitted from the first light emitting element, the area of the light emitting surface being smaller than the area of the light incident surface, And a light diffusing member provided on the light source device. [Selection] Figure 2

Description

  The present invention relates to a light source device and a projector.

  2. Description of the Related Art Conventionally, projectors that use white light generated using fluorescence and laser light for image display are known (see, for example, Patent Document 1 below).

JP 2011-154168 A

  By the way, since the divergence angle of fluorescence is larger than the divergence angle of laser light, it causes color unevenness. Thus, it is conceivable to increase the divergence angle by diffusing laser light with a diffusing element. However, a diffusing element with a large diffusion angle may reduce the transmittance of laser light.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a light source device and a projector capable of increasing a diffusion angle while suppressing loss of light.

  According to the first aspect of the present invention, the first light emitting element is provided on the optical path of the first light emitted from the first light emitting element, and the area of the light emitting surface is larger than the area of the light incident surface. There is provided a light source device including a small rod and a light diffusing member provided on the optical path.

  According to the light source device according to the first aspect, since the radiation angle of the first light can be expanded by the rod, a light diffusion member having a relatively small diffusion angle can be employed. Therefore, the diffusion angle can be increased while suppressing loss due to the light diffusing member.

In the first aspect, it is preferable that the light diffusing member is provided between the light emitting element and the light emitting surface.
According to this structure, the light of the magnitude | size according to the area of the light emission surface of a rod can be inject | emitted.

In the first aspect, the first collimating lens on which the first light that has passed through the rod enters, the second light emitting element, and the light emitted from the second light emitting element is converted into the second light. A wavelength converting element that converts the light into the second light, a second collimating lens on which the second light enters, the first light transmitted through the first collimating lens, and the second collimating lens It is preferable to further include a light combining optical element that combines the second light.
According to this configuration, for example, by appropriately adjusting the area of the light exit surface and the focal length of the first collimating lens, the light flux width of the first light transmitted through the first collimating lens, and the second Since the difference with the width of the light beam bundle of the second light transmitted through the collimating lens can be reduced, the color unevenness of the combined light can be reduced.

In the first aspect, the shape of the light spot formed on the wavelength conversion element by the light emitted from the second light emitting element is preferably similar to the shape of the light emitting surface.
According to this configuration, by adjusting the magnification of the first collimating lens and the magnification of the second collimating lens, the cross-sectional shape of the light beam of the first light transmitted through the first collimating lens, Since the cross-sectional shape of the light beam bundle of the second light transmitted through the two collimating lenses can be made uniform, the color unevenness of the combined light can be further reduced.

In the first aspect, it is preferable to further include a uniform illumination optical system into which light emitted from the light combining optical element is incident.
According to this configuration, uniform illumination light can be obtained by uniform illumination optics.

In the first aspect, the area of the light incident surface is preferably larger than a light beam size of light emitted from the light diffusion member.
According to this configuration, since the rod can swallow the light emitted from the light diffusing member well, loss due to the light diffusing member can be suppressed.

  According to the second aspect of the present invention, the light source device according to the first aspect, a light modulation device that forms image light by modulating light from the light source device according to image information, and the image light A projection optical system for projecting is provided.

  Since the projector according to the second aspect includes the light source device according to the first aspect, it is possible to project an image in which light loss is small and color unevenness is suppressed.

Schematic which shows the optical system of a projector. The figure which shows schematic structure of a light source device. The figure which shows the structure of the diffusion plate which concerns on a modification. The figure which shows the structure of the diffusion plate which concerns on a modification. The figure which shows the structure of the diffusion plate which concerns on a 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.

  An example of the projector according to the present embodiment will be described. The projector according to the present embodiment is a projection type image display device that displays a color image on a screen (projected surface). The projector includes three liquid crystal light modulation devices corresponding to red, green, and blue light. The projector includes a semiconductor laser that can obtain light with high luminance and high output as a light source of the lighting device.

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 a light source device 2, a color separation optical system 3, a light modulation device 4R, a light modulation device 4G, a light modulation device 4B, a combining optical system 5, and a projection optical system 6. Is roughly provided.

  In the present embodiment, the light source device 2 emits white light W as illumination light toward the color separation optical system 3.

  The color separation optical system 3 is for separating the illumination light WL into red light LR, green light LG, and blue light LB. The color separation optical system 3 includes a first dichroic mirror 7a and a second dichroic mirror 7b, a first total reflection mirror 8a, a second total reflection mirror 8b, a third total reflection mirror 8c, and a first A relay lens 9a and a second relay lens 9b are roughly provided.

  The first dichroic mirror 7a has a function of separating the illumination light WL from the light source device 2 into red light LR and other light (green light LG and blue light LB). The first dichroic mirror 7a transmits the separated red light LR and reflects other light (green light LG and blue light LB). On the other hand, the second dichroic mirror 7b has a function of separating other light into green light LG and blue light LB. The second dichroic mirror 7b reflects the separated green light LG and transmits the blue light LB.

The first total reflection mirror 8a is disposed in the optical path of the red light LR, and reflects the red light LR transmitted through the first dichroic mirror 7a toward the light modulation device 4R. On the other hand, the second total reflection mirror 8b and the third total reflection mirror 8c are arranged in the optical path of the blue light LB, and direct the blue light LB transmitted through the second dichroic mirror 7b toward the light modulation device 4B. reflect.
It is not necessary to arrange a total reflection mirror in the optical path of the green light LG, and the green light LG is reflected toward the light modulation device 4G by the second dichroic mirror 7b.

  The first relay lens 9a and the second relay lens 9b are arranged on the light emission side of the second dichroic mirror 7b in the optical path of the blue light LB. The first relay lens 9a and the second relay lens 9b function to compensate for the optical loss of the blue light LB caused by the optical path length of the blue light LB being longer than the optical path lengths of the red light LR and the green light LG. have.

  The light modulation device 4R modulates the red light LR according to image information while allowing the red light LR to pass therethrough, and forms image light corresponding to the red light LR. The light modulation device 4G modulates the green light LG according to image information while allowing the green light LG to pass therethrough, and forms image light corresponding to the green light LG. The light modulation device 4B modulates the blue light LB according to image information while allowing the blue light LB to pass therethrough, and forms image light corresponding to the blue light LB.

  For example, a transmissive liquid crystal panel is used for the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. In addition, a pair of polarizing plates (not shown) are arranged on the incident side and the emission side of the liquid crystal panel so that only linearly polarized light in a specific direction passes therethrough.

  A field lens 10R, a field lens 10G, and a field lens 10B are disposed on the incident side of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively. The field lens 10R, the field lens 10G, and the field lens 10B are for parallelizing the red light LR, the green light LG, and the blue light LB incident on the respective light modulation devices 4R, 4G, and 4B. It is.

  The combining optical system 5 combines the image light corresponding to the red light LR, the green light LG, and the blue light LB when the image light from the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B enters. The combined image light is emitted toward the projection optical system 6. For example, a cross dichroic prism is used for the combining optical system 5.

  The projection optical system 6 is composed of a projection lens group. The projection optical system 6 enlarges and projects the image light combined by the combining optical system 5 toward the screen SCR. Thereby, an enlarged color video (image) is displayed on the screen SCR.

(Light source device)
Next, the configuration of the light source device 2 will be described. FIG. 2 is a diagram showing a schematic configuration of the light source device 2.

  The light source device 2 includes a dichroic mirror 80, a uniform illumination optical system 81, a first light source unit 100, and a second light source unit 101.

  The dichroic mirror 80 has an optical characteristic of reflecting blue light and passing yellow fluorescence including red light and green light. Accordingly, the dichroic mirror 80 reflects the blue light B from the first light source unit 100 and transmits the fluorescent light Y emitted from the second light source unit 101 as described later, thereby synthesizing the white light. W is generated. The dichroic mirror 80 corresponds to a “photosynthesis optical element” recited in the claims.

  The uniform illumination optical system 81 includes a first lens array 120, a second lens array 130, a polarization conversion element 140, and a superimposing lens 150. However, the polarization conversion element 140 can be omitted. The uniform illumination optical system 81 makes the intensity distribution of the white light W uniform in the illuminated area. White light W emitted from the uniform illumination optical system 81 enters the color separation optical system 3.

  The first light source unit 100 includes a first light source 21, a condensing optical system 22, a diffusion plate (light diffusing member) 23, a tapered rod 24, and a first pickup lens 25.

  The first light source 21 includes a semiconductor laser (first light emitting element) 21a that emits a light beam composed of blue laser light (peak of emission intensity: about 445 nm). In this embodiment, the 1st light source 21 may be comprised from several semiconductor laser 21a, and may be comprised from one semiconductor laser 21a. The semiconductor laser 21a may be a semiconductor laser that emits blue light having a wavelength other than 445 nm (for example, 460 nm).

  The condensing optical system 22 condenses the blue light B from the first light source 21 in the vicinity of the diffusion plate 23.

  The diffusion plate 23 diffuses the blue light B from the first light source 21 at a certain angle. As the diffusion plate 23, for example, polished glass made of optical glass can be used.

  In the present embodiment, the diffusing plate 23 is disposed in front of the light incident surface 24 a of the tapered rod 24. In other words, the diffusion plate 23 is disposed between the first light source 21 and the light exit surface 24b.

  The taper rod 24 has a light incident surface 24 a that faces the diffusion plate 23 and a light emission surface 24 b that faces the first pickup lens 25. In the taper rod 24, the area of the light exit surface 24b is smaller than the area of the light incident surface 24a.

  The light incident surface 24 a of the taper rod 24 is larger than the light beam size of the blue light B diffused by the diffusion plate 23. Thereby, since the taper rod 24 can swallow the blue light B emitted from the diffusion plate 23 satisfactorily, the loss of the blue light B can be suppressed.

  Based on such a configuration, the tapered rod 24 can emit the blue light B incident on the light incident surface 24a from the light emitting surface 24b in a state where the radiation angle is widely converted.

  The second light source unit 101 includes a second light source 31, a collimating optical system 32, a second pickup lens 33, and a rotating fluorescent plate 35.

  The second light source 31 includes a plurality of semiconductor lasers 31 a that emit blue laser light similar to the first light source unit 100. The plurality of semiconductor lasers 31a are arranged in an array in the same plane orthogonal to the optical axis ax1. The second light source 31 emits excitation light E composed of a plurality of blue laser lights.

  Light (excitation light E) emitted from the second light source 31 enters the collimating optical system 32. The collimating optical system 32 converts the excitation light E emitted from the second light source 31 into a parallel light beam. The collimating optical system 32 is composed of, for example, a plurality of collimator lenses 32a arranged in an array. The plurality of collimator lenses 32a are arranged corresponding to the plurality of semiconductor lasers 31a.

  The second pickup lens 33 substantially collimates the fluorescence emitted from the rotating fluorescent plate 35 and the function of causing the excitation light E from the dichroic mirror 80 to enter the phosphor layer 42 of the rotating fluorescent plate 35 in a substantially condensed state. With functions. The second pickup lens 33 is a convex lens.

  In the present embodiment, the second light source unit 101 is configured such that the shape of the light spot formed by the excitation light E on the phosphor layer 42 is similar to the shape of the light exit surface 24 b of the tapered rod 24.

  Here, the shape of the light emission region of the fluorescence Y is substantially equal to the shape of the light spot region by the excitation light E formed on the phosphor layer 42. The shape of the illumination area by the blue light B is defined by the shape of the light exit surface 24b. Therefore, in the present embodiment, it can be said that the shape of the illumination area by the fluorescence Y and the shape of the illumination area by the blue light B satisfy a substantially similar relationship.

  The rotating fluorescent plate 35 includes a motor 50, a disc 40, a reflective film 41, and a phosphor layer (wavelength conversion element) 42. The rotating fluorescent plate 35 emits fluorescence Y toward the same side as the side on which the excitation light E is incident. The disc 40 is made of a metal disc having excellent heat dissipation, such as aluminum or copper, and can be rotated by a motor 50.

  The phosphor layer 42 is formed in a ring shape along the circumferential direction of the disk 40. The phosphor layer 42 is excited by the excitation light E from the first light source 21 and emits fluorescence Y in the second wavelength band. The fluorescence Y is yellow light including red light and green light.

  The phosphor layer 42 includes phosphor particles that absorb the excitation light E, convert it into yellow fluorescence Y, and emit it. As the phosphor particles, for example, YAG (yttrium / aluminum / garnet) phosphors can be used. In addition, the material for forming the phosphor particles may be one kind, or a mixture of particles formed using two or more kinds of materials may be used as the phosphor particles.

  A reflective film 41 is provided on the side of the phosphor layer 42 opposite to the side on which the excitation light E is incident. The reflection film 41 has a function of reflecting the fluorescence Y generated by the phosphor layer 42 upward. In addition, it is preferable that the reflective film 41 consists of a specular reflective surface. In this way, the fluorescence Y generated from the phosphor layer 42 is specularly reflected by the reflection film 41, whereby the fluorescence Y can be efficiently emitted from the phosphor layer 42.

  The fluorescence Y is collimated by the second pickup lens 33 and passes through the dichroic mirror 80. The fluorescent light Y is combined with the blue light B reflected by the dichroic mirror 80 to generate white light W.

  By the way, if there is a difference between the size of the illumination area due to the fluorescent light Y and the size of the illumination area due to the blue light B, color unevenness occurs in the white light W.

  In general, the fluorescence Y is emitted from the phosphor layer 42 with a large radiation angle, so that the illumination area is relatively large, which may cause the color unevenness. In the light source device 2 of the present embodiment, the illumination area by the blue light B is enlarged by increasing the emission angle of the blue light B, and the occurrence of color unevenness is suppressed by reducing the difference in the size of the illumination area. ing.

In the light source device 2, the radiation angle of the blue light B is widely converted by the diffusion plate 23 and the taper rod 24 in the first light source unit 100.
Here, it can be assumed that the diffusion plate 23 has a large diffusion angle. However, as the diffusion angle increases, the light transmittance of the diffusion plate 23 decreases, so that loss due to passing through the diffusion plate 23 increases, resulting in a decrease in utilization efficiency.

  Since the light source device 2 of the present embodiment expands the emission angle of the blue light B by combining the diffusion plate 23 and the taper rod 24, the taper rod 24 reduces the blue light B even if the diffusion angle of the diffusion plate 23 is suppressed. The radiation angle can be expanded.

In the present embodiment, as described above, the shape of the illumination area by the fluorescence Y and the shape of the illumination area by the blue light B satisfy a substantially similar relationship. Therefore, by appropriately adjusting the focal length 25 of the first pickup lens and the focal length of the second pickup lens 33, the shape of the illumination area by the blue light B transmitted through the first pickup lens 25 and the second pickup A difference from the shape of the illumination area due to the fluorescence Y transmitted through the lens 33 can be reduced.
Therefore, according to the light source device 2 of the present embodiment, it is possible to generate the white light W with reduced color unevenness while suppressing the loss of the blue light B.

  Further, according to the projector 1 provided with the light source device 2, the image light is formed using light with little light loss and suppressed color unevenness, so that it is possible to display a bright and uniform image with high reliability. It becomes sex.

  In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.

In the above embodiment, the case where a gap is provided between the diffusion plate 23 and the taper rod 24 is described as an example, but the present invention is not limited to this.
For example, as shown in FIG. 3, the diffusion plate 23 may be attached to the light incident surface 24 a of the taper rod 24.
Alternatively, the diffusion plate 23 may be disposed between the light incident surface 24a and the light exit surface 24b of the tapered rod 24, that is, inside the tapered rod 24, as shown in FIG.

Moreover, in the said embodiment, although the structure which fixedly arrange | positioned the diffusion plate 23 was mentioned as an example, you may make it rotate a diffusion plate.
FIG. 5 is a diagram showing a schematic configuration of the rotating diffusion plate 123.
As shown in FIG. 5, the rotation diffusion plate 123 can be rotated by a motor 122. Thereby, while changing the incident position of blue light B temporally, the temperature rise of the rotation diffusion plate 123 can be suppressed, and the rotation diffusion plate 123 can be rotated to efficiently dissipate heat. Thereby, even when the output of the blue light B is high, it is possible to prevent the rotating diffusion plate 123 from being damaged.

  Moreover, in the said embodiment, although the projector 1 provided with the three light modulation apparatuses 4R, 4G, and 4B was illustrated, it is also possible to apply to the projector which displays a color image | video with one light modulation apparatus. A digital mirror device may be used as the light modulation device.

  Moreover, although the example which mounted the light source device by this invention in the projector was shown in the said embodiment, it is not restricted to this. The light source device according to the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Light source device, 4R, 4G, 4B ... Light modulation device, 6 ... Projection optical system, 21 ... 1st light source part, 21a ... Semiconductor laser, 23, 123 ... Diffusing plate, 24 ... Taper rod, 25 DESCRIPTION OF SYMBOLS ... 1st pick-up lens, 31 ... 2nd light source, 31a ... Semiconductor laser, 33 ... 2nd pick-up lens, 35 ... Rotating fluorescent plate, 42 ... Phosphor layer, 81 ... Uniform illumination optical system.

Claims (7)

A first light emitting element;
A rod provided on the optical path of the first light emitted from the first light emitting element, and a light emitting surface having an area smaller than that of the light incident surface;
A light diffusing member provided on the optical path. The light source device according to claim 1, wherein the light diffusion member is provided between the light emitting element and the light emitting surface. A first collimating lens on which the first light passing through the rod is incident;
A second light emitting element;
A wavelength conversion element that converts light emitted from the second light emitting element into second light;
A second collimating lens on which the second light is incident;
The photosynthesis optical element which synthesize | combines the said 1st light which permeate | transmitted the said 1st collimating lens, and the said 2nd light which permeate | transmitted the 2nd collimating lens is further provided. The light source device according to 1. The light source device according to claim 3, wherein a shape of a light spot formed on the wavelength conversion element by the light emitted from the second light emitting element is similar to a shape of the light emitting surface. The light source device according to claim 3, further comprising a uniform illumination optical system into which light emitted from the light combining optical element is incident. The light source device according to any one of claims 1 to 5, wherein an area of the light incident surface is larger than a light beam size of light emitted from the light diffusion member. The light source device according to any one of claims 1 to 6,
A light modulation device that forms image light by modulating light from the light source device according to image information;
A projection optical system that projects the image light.

Images