JP2013047736A - Light source device and projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device and a projection type display device, which use light emitting from a phosphor layer and achieve reduction in size and cost of an optical system.SOLUTION: The light source device includes a light source, a phosphor layer 110 that generates color light by using incident light 101 from the light source as excitation light, and an optical multilayer film 130 that is disposed on an interface where the color light generated in the phosphor layer 110 exits and transmits or reflects the light in accordance with optical characteristics. The optical multilayer film 130 transmits a component of the color light scattered in the phosphor layer 110, the component propagating in a direction at a first angle with respect to the principal ray of the incident light 101 from the light source to the phosphor layer 110, and reflects a component propagating in a direction at a second angle larger than the first angle.

Description

  The present invention relates to a light source device and a projection display device.

  Conventionally, projection display apparatuses using a lamp such as a high-pressure mercury lamp as a light source are known. As for the projection display device, a technique for efficiently taking in light emitted from a lamp into an optical system has been developed. For example, light emitted from the lamp is collected by a reflecting mirror and guided to an optical component disposed ahead of the reflecting mirror. The lamp has a large calorific value due to its characteristics, and it is relatively difficult to control the temperature. Further, the life of the lamp is generally 2000 hours to 3000 hours, and maintenance is an issue for the use of the lamp in the projection display device.

  Under these circumstances, in recent years, a projection display device using an LED (light emitting diode) or an LD (laser diode) as a semiconductor light source has been developed. A semiconductor light source has an extremely long life of about 10 times that of a general lamp and consumes less power. Therefore, it is expected to be applied to a projector or a television.

JP 2004-341105 A JP 2010-256457 A

  The LD is characterized by high directivity and straightness. Since the light from the LD is less spread, the optical system using the LD can use the light efficiently even if the optical component is downsized. Miniaturization of the optical component is advantageous for miniaturization of an optical system from an illumination optical system including a relay lens or the like to a projection optical system including a projection lens or the like, and can also reduce the manufacturing cost.

  In a projection display apparatus using an LD, a plurality of LDs are arranged as a light source in order to obtain brightness necessary for displaying an image. The light source is combined with an LD for each color light for color display. As an optical system from the light source to the projection optical system, a complicated system composed of many elements is configured, and it is difficult to construct an inexpensive system.

  With regard to such a problem, for example, Patent Documents 1 and 2 propose a technique for generating light from a phosphor using excitation light as light emitted from an LD. In this case, a plurality of different color light LDs are not required, and an inexpensive system can be constructed.

  In general, light emitted from a phosphor does not have high directivity and straightness like an LD, and scatters over a wide angle range. For this reason, in the conventional configuration using a phosphor, it is difficult to efficiently use light. In order to capture light effectively, the optical component has an increased outer diameter and aperture. This leads to an increase in the size of the optical system and may hinder the construction of an inexpensive system.

  The present invention has been made in view of the above, and uses a light emitted from a phosphor layer to obtain a light source device and a projection display device that can realize downsizing and cost reduction of an optical system. For the purpose.

  In order to solve the above-described problems and achieve the object, the present invention provides a light source, a phosphor layer that generates color light using light incident from the light source as excitation light, and the color light generated in the phosphor layer. An optical multilayer film that is provided at an emission interface and transmits and reflects light according to optical characteristics, and the optical multilayer film includes the color light scattered from the phosphor layer and the light source from the light source. The optical characteristic of transmitting the component traveling in the direction of the first angle with respect to the principal ray of light incident on the phosphor layer and reflecting the component traveling in the direction of the second angle larger than the first angle. It is characterized by having.

  According to the present invention, the light source device transmits light components generated in the phosphor layer in a small angle range through the optical multilayer film, so that the light can be used efficiently even if the optical component is downsized. To do. By reducing the size of the optical components, the entire optical system can be reduced in size and the manufacturing cost can be reduced. Of the light generated in the phosphor layer, a component in a large angle range can be effectively utilized by being reflected again by the phosphor layer after being reflected by the optical multilayer film. Thereby, the light source device and the projection display device can use the light emitted from the phosphor layer, and can realize downsizing and cost reduction of the optical system.

FIG. 1 is a diagram showing a schematic configuration of a projection display apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a schematic cross-sectional configuration of the rotating body. FIG. 3 is a diagram for explaining the relationship between the incident angle to the optical multilayer film and the transmittance. FIG. 4 is a diagram for explaining the color light generated in the phosphor layer and the transmission characteristics of the optical multilayer film. FIG. 5 is a plan view of the color wheel on the side on which light from the light source is incident. FIG. 6 is a plan view of the color wheel on the side opposite to the side on which light from the light source is incident. FIG. 7 is a diagram illustrating a schematic cross-sectional configuration of a rotating body according to a modification.

  Embodiments of a light source device and a projection display device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a diagram showing a schematic configuration of a projection display apparatus according to an embodiment of the present invention. The light source 100 is an LD. The color wheel 300 generates a plurality of color lights by the light 101 incident from the light source 100. The color wheel 300 has a rotating shaft 31 and a rotating body 32. The rotating body 32 rotates around the rotating shaft 31 by driving the rotating shaft 31. The light source 100 and the color wheel 300 constitute a light source device.

  The light pipe 40 equalizes the intensity distribution of light incident from the color wheel 300. The light pipe 40 reflects light on the inner surface a plurality of times to form a rectangular surface light source with uniform light intensity on the emission side end surface. The relay lens 50 uniformly illuminates the display element 60 with a surface light source formed in the light pipe 40. The light source 100, the color wheel 300, the light pipe 40, and the relay lens 50 constitute an illumination optical system.

  The display element 60 modulates the illumination light from the relay lens 50 according to the video signal to form a display image. The display element 60 forms a display image by controlling the reflection direction of incident light, for example. The projection optical system 70 enlarges the display image formed by the display element 60 and projects it on the screen 80. Note that the configuration of the projection display apparatus can be modified as appropriate.

  FIG. 2 is a diagram illustrating a schematic cross-sectional configuration of the rotating body. The rotating body 32 includes a phosphor layer 110, a base material 120, and an optical multilayer film 130. The phosphor layer 110 generates color light using the light 101 incident from the light source 100 as excitation light. The phosphor layer 110 is applied to the surface of the substrate 120 on the side on which the light 101 is incident. The base material 120 is a transparent plate member made of glass or the like.

  The optical multilayer film 130 is formed on the surface of the substrate 120 opposite to the side on which the phosphor layer 110 is applied. The optical multilayer film 130 has a structure in which dielectric thin films are laminated. The optical multilayer film 130 transmits and reflects light according to optical characteristics. The optical multilayer film 130 is provided in the rotating body 32 at the interface for emitting the color light generated in the phosphor layer 110.

  The color light generated in the phosphor layer 110 is scattered inside the phosphor layer 110 and travels in a wide angle range. The color light incident on the base material 120 from the phosphor layer 110 passes through the base material 120 and enters the optical multilayer film 130.

  Here, the optical characteristics of the optical multilayer film 130 will be described by paying attention to components that travel in the directions of 0 °, θ1 °, θ2 °, and θ3 ° among the colored light scattered by the phosphor layer 110. All of 0 °, θ1 °, θ2 °, and θ3 ° are angles with respect to the principal ray of the light 101 incident on the phosphor layer 110 from the light source 100. The component traveling in the 0 ° direction travels in the same direction as the principal ray of the light 101. Note that θ1 °, θ2 °, and θ3 ° are angles satisfying 0 ° <θ1 ° <θ2 ° <θ3 ° <90 °.

  FIG. 3 is a diagram for explaining the relationship between the incident angle to the optical multilayer film and the transmittance. The optical multilayer film 130 has a characteristic of a low-pass filter that transmits light having a wavelength lower than a predetermined wavelength. The transmission characteristics of the optical multilayer film 130 generally vary depending on the incident angle of light. The transmission characteristics of the optical multilayer film 130 shift to the short wavelength side as the incident angles increase from 0 ° perpendicularly incident on the optical multilayer film 130 to θ1 °, θ2 °, and θ3 °.

  FIG. 4 is a diagram for explaining the color light generated in the phosphor layer and the transmission characteristics of the optical multilayer film. The spectrum 250 of the colored light generated in the phosphor layer 110 has an upper limit wavelength that can be transmitted through the optical multilayer film 130 at an incident angle of θ2 °, and an upper limit wavelength that can be transmitted through the optical multilayer film 130 at an incident angle of θ3 °. Located between.

  The optical multilayer film 130 transmits the components traveling in the directions of 0 °, θ1 °, and θ2 ° (first angle) in the color light scattered by the phosphor layer 110, and θ3 ° (second angle). The component traveling in the direction of is reflected. In the optical multilayer film 130, the maximum angle of components that can be transmitted among the color light incident from the phosphor layer 110 is set between θ2 ° and θ3 °. The first angle is smaller than the maximum angle. The second angle is larger than the maximum angle.

  Of the color light scattered by the phosphor layer 110, the component transmitted through the optical multilayer film 130 is emitted from the rotating body 32. Of the colored light scattered by the phosphor layer 110, the component reflected by the optical multilayer film 130 passes through the base material 120 and enters the phosphor layer 110. The color light that has entered the phosphor layer 110 after being reflected by the optical multilayer film 130 is scattered again together with the color light generated by the phosphor layer 110.

  The color wheel 300 allows components having a small angle range to pass through the optical multilayer film 130 out of the color light scattered by the phosphor layer 110, thereby enabling emission of color light having a uniform traveling direction. By aligning the traveling direction of the color light from the color wheel 300, the color wheel 300 can efficiently make the color light incident on the light pipe 40.

  The projection display device narrows the angle range in which each color light scatters in the color wheel 300, so that light can be used efficiently even if the optical component is downsized. The projection display device can reduce the size of the entire optical system and the manufacturing cost by reducing the size of the optical components. The color wheel 300 reflects the component in the large angle range of the color light scattered by the phosphor layer 110 after being reflected by the optical multilayer film 130 and then again scattered by the phosphor layer 110. The color wheel 300 can be used effectively by scattering the light returned from the optical multilayer film 130 again by the phosphor layer 110. Thereby, the light source device and the projection display device can use the light emitted from the phosphor layer 110, and can realize downsizing and cost reduction of the optical system.

  FIG. 5 is a plan view of the color wheel on the side on which light from the light source is incident. FIG. 6 is a plan view of the color wheel on the side opposite to the side on which light from the light source is incident. The phosphor layer 110 has a red (R) phosphor layer 110R, a green (G) phosphor layer 110G, and a blue (B) phosphor layer 110B.

  The phosphor layer for R light 110 </ b> R is a first phosphor layer that generates R light as first color light using light 101 incident from the light source 100 as excitation light. The G light phosphor layer 110 </ b> G is a second phosphor layer that generates G light, which is second color light, using light 101 incident from the light source 100 as excitation light. The phosphor layer for B light 110B is a third phosphor layer that generates B light, which is the third color light, using the light 101 incident from the light source 100 as excitation light. The phosphor layer for R light 110R, the phosphor layer for G light 110G, and the phosphor layer for B light 110B are formed so as to divide a belt-like region forming a circle into three.

  The optical multilayer film 130 includes an optical multilayer film for R light 130R, an optical multilayer film for G light 130G, and an optical multilayer film for B light 130B. The R light optical multilayer film 130R is provided corresponding to the R light phosphor layer 110R. The R light phosphor layer 110 </ b> R and the R light optical multilayer film 130 </ b> R are arranged in the same position in the rotation direction of the rotating body 32. The optical multilayer film for R light 130 </ b> R is a first optical multilayer film having an optical characteristic of transmitting a component traveling in the first angle direction of the R light and reflecting a component traveling in the second angle direction. It is.

  The G light optical multilayer film 130G is provided corresponding to the G light phosphor layer 110G. The G light phosphor layer 110 </ b> G and the G light optical multilayer film 130 </ b> G are arranged with their positions matched in the rotational direction of the rotating body 32. The G light optical multilayer film 130G is a second optical multilayer film having an optical characteristic of transmitting a component traveling in the first angle direction of the G light and reflecting a component traveling in the second angle direction. It is.

  The B light optical multilayer film 130B is provided corresponding to the B light phosphor layer 110B. The phosphor layer for B light 110 </ b> B and the optical multilayer film for B light 130 </ b> B are arranged so that their positions coincide with each other in the rotation direction of the rotating body 32. The optical multilayer film 130B for B light transmits a component that travels in the direction of the first angle of the B light, and reflects the component that travels in the direction of the second angle. It is.

  The color wheel 300 rotates the rotating body 32 in a state where the light 101 from the light source 100 is incident, so that the R light phosphor layer 110R, the G light phosphor layer 110G, and the B light phosphor layer 110B. Sequentially, light 101 enters. When the light 101 is incident on the R light phosphor layer 110R, the color wheel 300 emits R light from the R light optical multilayer film 130R.

  The color wheel 300 emits G light from the optical multilayer film 130G for G light when the light 101 is incident on the phosphor layer 110G for G light. The color wheel 300 emits B light from the optical multilayer film 130B for B light when the light 101 is incident on the phosphor layer 110B for B light. In this way, the color wheel 300 sequentially emits R light, G light, and B light. The illumination optical system makes R light, G light, and B light incident on the display element 60 in a time-sharing manner.

  The color wheel 300 is not limited to one that generates three color lights of R, G, and B. The color wheel 300 may generate color light other than R, G, and B. The color wheel 300 only needs to generate color light of at least two colors.

  The color wheel 300 may generate color light such as yellow, magenta, and cyan. The color wheel 300 can be configured to generate desired color light by applying the phosphor layer 110 and the optical multilayer film 130 formed according to these color lights.

  The illumination optical system may apply a light source 100 that emits a certain color light, for example, B light, and the color light may simply pass through the color wheel 300. In this case, the color wheel 300 allows the B light from the light source 100 to pass through by providing the rotating body 32 with a region where the phosphor layer 110 and the optical multilayer film 130 are not provided. When a blue LD is used for the light source 100, the phosphor layer 110 can be efficiently excited with high energy, and the color light generated in the phosphor layer 110 can be extracted.

  FIG. 7 is a diagram illustrating a schematic cross-sectional configuration of a rotating body according to a modification. In the rotating body 33 according to the modification, the optical multilayer film 130 is provided on the same side as the side on which the light 101 from the light source 100 is incident with respect to the phosphor layer 110. The optical multilayer film 130 is formed on the surface of the substrate 120 on the light incident side. The optical multilayer film 130 is provided on the interface of the rotating body 33 for emitting the color light generated in the phosphor layer 110.

  The phosphor layer 110 is applied to the surface of the substrate 120 opposite to the side on which the optical multilayer film 130 is formed. The reflective film 140 is provided on the opposite side of the phosphor layer 110 from the side bonded to the substrate 120. The reflective film 140 reflects the color light from the phosphor layer 110.

  Light 101 from the light source 100 passes through the optical multilayer film 130 and the base material 120 and enters the phosphor layer 110. Color light reflected and scattered from the phosphor layer 110 is incident on the optical multilayer film 130 to the side on which the light 101 is incident. The optical multilayer film 130 transmits the components traveling in the directions of 0 °, θ1 °, and θ2 ° (first angle) in the color light scattered by the phosphor layer 110, and θ3 ° (second angle). The component traveling in the direction of is reflected.

  The reflective film 140 reflects the color light transmitted through the phosphor layer 110 to the side opposite to the side on which the light 101 is incident. The color light that has entered the phosphor layer 110 after being reflected by the reflective film 140 is scattered again together with the color light generated by the phosphor layer 110. Even when such a rotating body 33 is applied, the color wheel 300 can transmit components in a small angle range out of the color light scattered by the phosphor layer 110 through the optical multilayer film 130 and emit color light whose traveling direction is aligned. And

  The color wheel 300 can effectively use the light transmitted through the phosphor layer 110 to the side opposite to the side on which the light 101 is incident by scattering the color light reflected by the reflective film 140 again. Note that the reflective film 140 may be omitted as appropriate.

31 Rotating shaft 32, 33 Rotating body 40 Light pipe 50 Relay lens 60 Display element 70 Projection optical system 80 Screen 100 Light source 101 Light 110 Phosphor layer 110R Phosphor layer for R light 110G Phosphor layer for G light 110B Fluorescence layer for B light Body layer 120 Base material 130 Optical multilayer film 130R Optical multilayer film for R light 130G Optical multilayer film for G light 130B Optical multilayer film for B light 140 Reflective film 250 Spectrum 300 Color wheel

Claims (5)

A light source;
A phosphor layer that generates color light using light incident from the light source as excitation light;
An optical multilayer film provided at an interface for emitting the color light generated in the phosphor layer, and transmitting and reflecting light according to optical characteristics;
The optical multilayer film transmits a component traveling in a direction of a first angle with respect to a principal ray of light incident on the phosphor layer from the light source among the colored light scattered by the phosphor layer, A light source device having the optical characteristic of reflecting a component traveling in a direction of a second angle larger than the first angle.   2. The light source device according to claim 1, wherein the optical multilayer film is provided on a side opposite to a side on which light from the light source is incident with respect to the phosphor layer.   2. The light source device according to claim 1, wherein the optical multilayer film is provided on the same side as the side on which the light from the light source is incident with respect to the phosphor layer. A color wheel for generating a plurality of the colored lights by light incident from the light source;
The color wheel includes a first phosphor layer that is the phosphor layer that generates first color light using light incident from the light source as excitation light, and second color light using light incident from the light source as excitation light. A second phosphor layer that is the phosphor layer for generating
The first optical multilayer film, which is the optical multilayer film corresponding to the first phosphor layer, transmits a component traveling in the direction of the first angle in the first color light, and transmits the second Reflects the component traveling in the direction of the angle,
The second optical multilayer film, which is the optical multilayer film corresponding to the second phosphor layer, transmits a component traveling in the direction of the first angle of the first color light, and transmits the second The light source device according to any one of claims 1 to 3, wherein a component traveling in a direction of an angle is reflected. Illumination optics,
A display element that modulates illumination light from the illumination optical system to form a display image;
A projection optical system that projects the display image formed by the display element,
The illumination optical system includes:
A light source;
A phosphor layer that generates color light using light incident from the light source as excitation light;
An optical multilayer film provided at an interface for emitting the color light generated in the phosphor layer, and transmitting and reflecting light according to optical characteristics;
The optical multilayer film transmits a component traveling in a direction of a first angle with respect to a principal ray of light incident on the phosphor layer from the light source among the colored light scattered by the phosphor layer, A projection display device having the optical characteristic of reflecting a component traveling in a direction of a second angle larger than the first angle.

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