JP5675320B2 - Light source device and projection-type image display device - Google Patents

Description

  The present invention relates to a light source device used for a projection display apparatus.

  In a projection-type image display apparatus that enlarges and displays a display screen of an image display element having a structure in which a plurality of reflective or transmissive liquid crystal panels or micromirrors are arranged on a screen or board as a projection surface, the projection surface is sufficient. The illumination optical system has been devised so as to obtain an enlarged image having a size and brightness. In particular, development of a projection-type image display apparatus using solid-state light emitting elements such as red, green, and blue light emitting diodes and organic EL has been performed.

  For example, there has been proposed a light source device that emits light with high efficiency even when excitation light emitted from a solid light source is visible light (see Patent Document 1).

JP 2009-277516 A

  When Patent Document 1 is applied, the following problems can be considered. FIG. 5 is a main part configuration diagram of a light source device assumed as a problem. In FIG. 5, the excitation light 2 emitted from the excitation light source 1 becomes substantially parallel light by the collimator lens 3 and enters the dichroic mirror 4. The dichroic mirror 4 has a characteristic of reflecting the wavelength range of the excitation light 2 and transmitting the wavelength range of the fluorescent light 8. Therefore, the excitation light 2 is reflected by the dichroic mirror 4, passes through the condenser lens 5, and then enters the rotation-controllable disk 100 coated with the phosphor 7. The condensing lens 5 has a curvature so that the incident parallel light is condensed at one place on the disk 100. The phosphor 7 on the disk 100 excited by the excitation light 2 emits fluorescence light 8. After passing through the condenser lens 5, the fluorescent light 8 becomes substantially parallel light, passes through the dichroic mirror 4, and enters the subsequent illumination optical system. Since the fluorescent light emitted from the phosphor 7 is emitted in all directions, there is fluorescent light 800 that cannot be captured by the condenser lens 5. In addition, since there is unconverted excitation light 200 that has not been converted into fluorescent light, the light utilization efficiency is reduced.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a light source device with improved brightness efficiency in a light source device that emits a phosphor with excitation light.

  In order to solve the above problems, one of the desirable embodiments of the present invention is as follows.

  The light source device includes a light source that emits excitation light and a metal member on which the excitation light is incident. The metal member has a recess at a site where the excitation light is incident, and the excitation light is emitted into the recess. A phosphor for generating fluorescent light when excited is applied.

  ADVANTAGE OF THE INVENTION According to this invention, in the light source device which light-emits fluorescent substance with excitation light, the light source device which improved the brightness efficiency can be provided.

The principal part block diagram of the light source device in a 1st Example. 1 is a diagram illustrating an optical system of a projection display apparatus according to a first embodiment. The principal part block diagram of the light source device in a 2nd Example. The figure which shows the optical system of the projection type video display apparatus in a 2nd Example. The principal part block diagram of the light source device assumed as a subject.

  Hereinafter, examples will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same part and the description is abbreviate | omitted about what was once demonstrated.

  FIG. 1 is a configuration diagram of a main part of a light source device according to a first embodiment.

  FIG. 1A shows an overall image of the optical system. The excitation light 2 emitted from the excitation light source 1 becomes substantially parallel light by the collimating lens 3 and enters the dichroic mirror 4. Since the dichroic mirror 4 has the above-described characteristics, the excitation light 2 is reflected by the dichroic mirror 4, passes through the condenser lens 5, and enters the metal member 6. The metal member 6 has a recess at a site where the excitation light is incident, and a phosphor 7 for generating fluorescent light from the excitation light is applied in the recess. The concave portion has a tapered shape such that the exit side opening of the fluorescent light 8 is larger than the entrance side opening.

  In FIG. 5, since organic silicon resin or the like was used as a binder for dispersing and solidifying the phosphor, it was necessary to rotate to prevent burning due to temperature. However, by using an inorganic binder, No body rotation is required. The fluorescent light 8 emitted from the phosphor 7 becomes substantially parallel light after passing through the condenser lens 5, passes through the dichroic mirror 4, and enters the subsequent illumination optical system.

  FIG. 1B is an enlarged view of the metal member 6 and shows the divergent light of the fluorescent light 8. The fluorescent light 8 emitted from the phosphor 7 is reflected by the taper portion of the metal member 6, and is converged to a certain angle of divergence at the opening of the metal member 6 without being diverged in all directions. All fluorescent light 8 can be captured by the lens 5. In addition, in order to reduce the angle of the fluorescent light 8 that directly diverges out of the metal member 6 without being reflected by the tapered portion, the region where the phosphor is applied to the tapered portion is deeper than half the depth of the concave portion. It is desirable to make it an area.

  FIG. 1C is an enlarged view of the metal member 6 and shows the light beam of the excitation light 2. Of the excitation light 2 incident on the phosphor 7, the unconverted excitation light 200 that has not been converted into fluorescence light is reflected by the phosphor 7, and is incident again on the phosphor 7 applied at another location, and the fluorescence. It is converted into light 8. Therefore, it is desirable that the phosphor is applied to at least two surfaces of the tapered portion. There is excitation light that is not converted into fluorescent light 8 even if it is incident on two surfaces of the phosphor 7, but the probability is low, so there is almost no problem.

  FIG. 2 is a diagram showing an optical system of a projection display apparatus including the light source device of FIG. When distinguishing elements arranged in the optical path of each color light, R, G, and B representing the color light are added after the reference numerals, and when it is not necessary to distinguish, the subscript of the color light is omitted.

  First, the principle of applying red light and green light to the liquid crystal display elements 19R and 19G with uniform illuminance will be described.

  A blue laser is used as the excitation light source 1. This is because the light emission area of the light source is small, so that it is easy to collect and collimate light. The blue excitation light 2 emitted from the excitation light source 1 enters the dichroic mirror 4 as described above. The dichroic mirror 4 has a characteristic of reflecting blue light and transmitting yellow light (green light and red light). Therefore, the blue excitation light 2 is reflected by the dichroic mirror 4, transmitted by the condenser lens 5, and condensed on the metal member 6 coated with a yellow phosphor (not shown).

  The yellow fluorescent light excited by the yellow phosphor is emitted from the metal member 6, passes through the condenser lens 5, becomes substantially parallel, passes through the dichroic mirror 4, and enters the polarization conversion integrator.

  The polarization conversion integrator is an optical integrator that performs uniform illumination including the first lens group 10 and the second lens group 11, and polarization of a polarization beam splitter array that converts light into linearly polarized light by aligning the polarization direction of light to a predetermined polarization direction. Conversion element 12.

  The light from the second lens group 11 is substantially aligned by a polarization conversion element 12 into a predetermined polarization direction, for example, Y-polarized light of linearly polarized light. The projected images of the lens cells of the first lens group 10 are superimposed on the liquid crystal display elements 19R and 19G by the condenser lens 13 and the collimating lenses 17R and 17G, respectively.

  At that time, the yellow fluorescent light passing through the condenser lens 13 is separated into red light and green light by the dichroic mirror 14. Since the dichroic mirror 14 has characteristics of transmitting green light and reflecting red light, among yellow light incident on the dichroic mirror 14, green light passes through the dichroic mirror 14 and is reflected by the reflection mirror 15. The collimating lens 17G becomes substantially parallel, and after the X-polarized light is removed by the incident-side polarizing plate 18G, the light enters the liquid crystal display 19G. On the other hand, the red light is reflected by the dichroic mirror 14, reflected by the reflecting mirror 16, becomes substantially parallel by the collimating lens 17R, and is incident on the liquid crystal display 19R after removing the X-polarized light by the incident side polarizing plate 18R. To do.

Next, the principle of irradiating the liquid crystal display device 19B with blue light with uniform illuminance will be described.
The light source 23 is a blue light source, for example, an LED light source. The blue light emitted from the light source 23 passes through the collimating lens 24 and the collimating lens 25, becomes substantially parallel, and enters the polarization conversion integrator for blue light.

  The polarization conversion integrator for blue light includes an optical integrator that performs uniform illumination including a third lens group 26 and a fourth lens group 27, and a polarization beam that converts light into a linearly polarized light with a predetermined polarization direction. And a polarization conversion element 28 of the splitter array. The light from the fourth lens group 27 is substantially aligned with a predetermined polarization direction, for example, Y-polarized light of linearly polarized light by the polarization conversion element 28. The projected images of the lens cells of the third lens group 26 are superimposed on the liquid crystal display elements 19B by the condenser lens 29, the reflecting mirror 30, and the collimating lens 17B, respectively. At that time, the X-polarized light is removed by the incident-side polarizing plate 18B.

  Subsequently, each of the liquid crystal display elements 19 (19R, 19G, 19B) constituting the light intensity modulation unit has a higher degree of polarization due to the incident-side polarizing plate 18 (18R, 18G, 18B) whose transmission axis is the Y direction. The light intensity is modulated in accordance with a color video signal (not shown) to form an X-polarized optical image of each color light.

  The X-polarized optical images of the respective color lights thus formed are incident on the exit-side polarizing plate 20 (20R, 20G, 20B). The exit-side polarizing plates 20R, 20G, and 20B are polarizing plates that have the transmission direction in the X direction. Thereby, an unnecessary polarized light component (here, Y-polarized light) is removed, and the contrast is increased.

  The thus formed Y-polarized optical image of each color light is incident on the light combining prism 21 which is a light combining means. At this time, the green light optical image is incident as X-polarized light (P-polarized light with respect to the dichroic film surface of the light combining prism 21). On the other hand, in the blue optical path and the red optical path, a 1 / 2λ wavelength plate (not shown) is provided between the output-side polarizing plates 20B and 20R and the light combining prism 21, so that the optical images of the X-polarized blue light and red light are The light is converted into an optical image of Y-polarized light (S-polarized light with respect to the dichroic film surface that performs color composition of the light combining prism 21) and then enters the light combining prism 21. This is because the spectral characteristics of the dichroic film are taken into consideration, so that the light is efficiently synthesized by so-called SPS synthesis in which green light is P-polarized light and red light and blue light are S-polarized light.

  Subsequently, in the light combining prism 21, a dichroic film (dielectric multilayer film) that reflects blue light and a dichroic film (dielectric multilayer film) that reflects red light are substantially X-shaped at the interface of four right-angle prisms. (Cross shape). Blue light and red light (S-polarized light with respect to the dichroic film surface) incident on the opposite incident surfaces among the three incident surfaces of the light combining prism 21 are crossed dichroic film for blue light and dichroic for red light. Each is reflected by the film. Further, the green light (P-polarized light with respect to the dichroic film surface) incident on the central incident surface travels straight. The optical images of these color lights are synthesized, and color image light (synthesized light) is emitted from the emission surface.

  The combined light emitted from the light combining prism 21 is projected onto a transmission or projection screen (not shown) by a projection lens 22 such as a zoom lens, and displays an enlarged projected image. Become.

  Here, the video display element has been described as a liquid crystal type video display element, but it goes without saying that the present invention can also be applied to a projection type video display apparatus using a DMD (Digital Mirror Device) element.

  FIG. 3 is a configuration diagram of the main part of the optical system of the light source device according to the second embodiment.

  FIG. 3A shows an overall image of the optical system. The difference from the first embodiment is that a rod lens 9 is mainly disposed between the condenser lens 5 and the metal member 6.

  FIG. 3B is an enlarged view of the metal member 6 and the rod lens 9 which is a glass member, and shows a divergent ray of the fluorescent light 8. Fluorescent light 8 emitted from the phosphor 7 enters the rod lens 9. The rod lens 9 has a tapered shape such that the exit side opening of the fluorescent light 8 is larger than the entrance side opening. Therefore, after the fluorescent light 8 is incident on the rod lens 9 and is repeatedly totally reflected inside the taper portion, it is narrowed down to a certain angle of divergence at the exit opening of the rod lens 9 without divergence in all directions. Therefore, all the fluorescent light 8 can be captured by the condenser lens 5.

  FIG. 3C is an enlarged view of the metal member 6 and the rod lens 9, and shows the light beam of the excitation light 2. As in FIG. 1C, the unconverted excitation light 200 is reflected by the phosphor 7, is incident again on the phosphor 7 applied at another location, and is converted into the fluorescence light 8. Therefore, it is desirable that the phosphor is applied to at least two surfaces of the recess. There is excitation light that is not converted into fluorescent light 8 even if it is incident on two surfaces of the phosphor 7, but the probability is low, so there is almost no problem.

  FIG. 4 is a diagram showing an optical system of the projection display apparatus including the light source device of FIG.

  The blue excitation light 2 emitted from the excitation light source 1 becomes substantially parallel by the collimating lens 3 and enters the dichroic mirror 31. The dichroic mirror 31 has a characteristic of reflecting blue light and transmitting green light. Accordingly, the blue excitation light is reflected by the dichroic mirror 31, condensed by the condenser lens 5, passes through the rod lens 9, and then enters the metal member 6 coated with a green phosphor (not shown).

  The green light excited by the green phosphor passes through the condenser lens 5 and becomes substantially parallel, passes through the dichroic mirror 31, passes through the condenser lens 32, and enters the dichroic mirror 33. The dichroic mirror 33 has a characteristic of transmitting green light and reflecting red light and blue light. Accordingly, the green light passes through the dichroic mirror 33 and enters the multiple reflection element 40. The condensing lens 32 is set to have such a curvature that the incident substantially parallel light is condensed on the incident opening of the multiple reflection element 40.

  The light source 34 is a red light source, for example, an LED light source. The red light emitted from the light source 34 becomes parallel by the collimating lens 35 and enters the dichroic mirror 38. The dichroic mirror 38 has a characteristic of transmitting red light and reflecting blue light. Therefore, the red light passes through the dichroic mirror 38, passes through the condenser lens 39, and enters the dichroic mirror 33.

  On the other hand, the light source 36 is a blue light source, for example, an LED light source. The blue light emitted from the light source 36 is collimated by the collimator lens 37 and enters the dichroic mirror 38. The dichroic mirror 38 has a characteristic of transmitting red light and reflecting blue light. Accordingly, the blue light is reflected by the dichroic mirror 38, passes through the condenser lens 39, and enters the dichroic mirror 33. The dichroic mirror 33 has a characteristic of transmitting green light and reflecting red light and blue light. Therefore, the red light and the blue light incident on the dichroic mirror 33 are reflected by the dichroic mirror 33 and enter the multiple reflection element 40.

  The condensing lens 39 is set to have such a curvature that the incident substantially parallel light is condensed on the entrance opening of the multiple reflection element 40. The red light, green light, and blue light incident on the multiple reflection element 40 are reflected a plurality of times by the multiple reflection element 40, and become light having a uniform illuminance distribution on the exit aperture surface of the multiple reflection element 40. The shape of the exit aperture surface of the multiple reflection element 40 is substantially similar to that of the DMD element 43. The condenser lens 41 is set to a curvature that enlarges and forms an image formed on the exit aperture surface of the multiple reflection element 40 on the DMD element 43. Accordingly, red light, green light, and blue light emitted from the exit aperture surface of the multiple reflection element 40 pass through the condenser lens 41, are reflected by the reflection mirror 42, and are then irradiated onto the DMD element 43 with a uniform illuminance distribution. The

  The excitation light source 1, the light source 34, and the light source 36 are solid-state light emitting elements with a fast response speed and can be time-division controlled. Accordingly, each color light is modulated by the DMD element 43 in a time division manner for each color light. Each color light reflected by the DMD element 43 enters the projection lens 44 and is enlarged and projected on a screen (not shown).

  Although the video display element has been described here as a DMD element, it is needless to say that the present invention can also be applied to a projection type video display apparatus using a liquid crystal type video display element.

DESCRIPTION OF SYMBOLS 1 ... Excitation light source, 2 ... Excitation light, 3 ... Collimating lens, 4 ... Dichroic mirror, 5 ... Condensing lens, 6 ... Metal member, 7 ... Phosphor, 8 ... Fluorescent light, 9 ... Rod lens, 200 ... Unconverted Excitation light

Claims (6)

A light source that emits excitation light;
A condensing lens for condensing excitation light from the light source;
A metal member on which the excitation light condensed by the condenser lens is incident,
The metal member has a recess at a site where excitation light collected by the condenser lens is incident, and a phosphor for generating fluorescent light from the excitation light is applied in the recess,
The fluorescent light excited by the phosphor is configured to enter the condenser lens ,
A light source device comprising a glass member having a tapered shape at an opening of the recess .   The light source device according to claim 1, wherein the recess has a tapered shape.   The light source device according to claim 1, wherein the phosphor is applied to at least two surfaces in the recess.   The light source device according to claim 1, wherein the phosphor is applied to a region deeper than half of the depth of the recess. A light source device;
An image display element;
An illumination optical system having a plurality of optical elements that irradiate the image display element with light from the light source device;
In a projection display apparatus comprising a projection lens that magnifies and projects an optical image formed by the image display element, the light source device includes:
A light source that emits excitation light;
A condensing lens for condensing excitation light from the light source;
A metal member on which the excitation light condensed by the condenser lens is incident,
The metal member has a recess at a site where excitation light collected by the condenser lens is incident, and a phosphor for generating fluorescent light from the excitation light is applied in the recess,
The fluorescent light excited by the phosphor is configured to enter the condenser lens ,
A projection-type image display device comprising a glass member having a tapered shape at an opening of the recess . 6. The projection display apparatus according to claim 5 , wherein the light source device is obtained by exciting a phosphor using a solid light emitting element as excitation light.

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