JP2020052148A - Illumination device and projection type video display device - Google Patents

Abstract

To provide an illumination device capable of reducing the size while ensuring the efficiency of light use.SOLUTION: The illumination device includes: a lens unit 400 constituted of one or more lenses, which is disposed on the optical axis of the illumination light emitted from the light source; a total reflection prism 235 in which illumination light passing through the lens unit is incident on the light incident surface; and a display element 236 which is irradiated with illumination light incident on total reflection prism. The main plane of a lens of the lens unit, which is disposed immediately in front of the light entrance surface to emit illumination light to the light entrance surface of the total reflection prism, is arranged to be non-parallel to the light incident surface at an angle to the optical axis.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a lighting device used for, for example, a projection display apparatus.

  Patent Literature 1 discloses a projection display apparatus in which light obtained by exciting a phosphor provided on a phosphor wheel with an excitation light source is used as illumination light.

JP-A-2006-031402

  The present disclosure provides an illumination device and a projection-type image display device in which the size of a prism element that propagates illumination light to a display element is reduced and the device is reduced in size without lowering light use efficiency.

  The illumination device according to the present disclosure includes a light source, a lens unit disposed on an optical axis of illumination light emitted from the light source, one or more lenses, and illumination light passing through the lens unit. A total reflection prism incident on the incident surface, and a display element illuminated with illumination light incident on the total reflection prism, and immediately before the light incident surface so as to emit illumination light to the light incident surface of the total reflection prism. The main plane of the lens of the lens unit disposed at the position is not parallel to the light incident surface and is inclined with respect to the optical axis.

  INDUSTRIAL APPLICABILITY The present disclosure is effective in reducing the size of an illumination device without lowering the light use efficiency of the illumination device even when the illumination light to the prism is irradiated obliquely to the prism surface.

FIG. 1 is a diagram illustrating a configuration of a projection display apparatus equipped with a lighting device according to an embodiment. Diagram of phosphor wheel used in lighting device in embodiment Diagram of a transfer optical system used in the illumination device according to the embodiment Diagram of a prism used in a lighting device according to an embodiment FIG. 4 is a diagram illustrating a spot diagram on a display element surface of the illumination device according to the embodiment. The figure which shows the spot diagram of the display element surface concerning a comparative example.

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, an unnecessary detailed description may be omitted. For example, a detailed description of a well-known item or a redundant description of substantially the same configuration may be omitted. This is to prevent the following description from being unnecessarily redundant and to facilitate understanding by those skilled in the art.

The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the claimed subject matter.
(Embodiment)
Hereinafter, an embodiment will be described with reference to FIGS. 1 to 5.

[1. Overall configuration]
FIG. 1 is a diagram for explaining a configuration of an optical system of a projection display apparatus 1 equipped with the illumination device of the present disclosure. For convenience of the following description, FIGS. 1 to 4 assume an XYZ orthogonal coordinate system shown in the drawings.

  First, the light source optical system 20 of the projection display 1 will be described. The laser light source 201, which is an excitation light source, is a blue semiconductor laser, and includes a plurality of semiconductor lasers to realize a high-luminance lighting device. In FIG. 1, for example, five blue semiconductor lasers are illustrated side by side, but a plurality of blue semiconductor lasers are arranged on a plane in a matrix. The laser light source 201 is an example of a light source. The laser light, which is the excitation light emitted from each laser light source 201, is collimated by the corresponding collimating lens 202. The light emitted from the collimating lens 202 is substantially parallel light. The entire light flux of the parallel light is condensed by the lens 203, passes through the diffusion plate 204, and is then converted into substantially parallel light again by the lens 205. The laser beam that has been made substantially parallel by the lens 205 enters a dichroic mirror 206 that is arranged at an angle of about 45 degrees with respect to the optical axis.

  The diffusion plate 204 is a glass flat plate, and has a diffusion surface provided with fine irregularities on one surface. Further, the dichroic mirror 206 has a characteristic of reflecting light in the wavelength range of the blue semiconductor laser and transmitting light in other wavelength ranges.

  The laser light incident on the dichroic mirror 206 in the −X direction in the figure is reflected by the dichroic mirror 206 and emitted in the −Z direction in the figure. Thereafter, the laser light is condensed by the lenses 207 and 208 to excite the phosphor formed on the phosphor wheel device 10.

  As shown in the side view of FIG. 2A, the phosphor wheel device 10 includes a motor 101 and a rotating base member 102 formed of a disk-shaped plate that is driven to rotate about the rotation axis of the motor 101. Is done.

  As shown in the front view of FIG. 2 (b), the rotating base material 102 has a predetermined width W inside and outside the circumference on the circumference at a distance R1 from the rotation axis center A of the phosphor wheel. A phosphor section 103, a green phosphor section 104, and an opening 105 are formed.

  When the laser light from the laser light source 201 is focused on the red phosphor section 103 of the phosphor wheel device 10, the red phosphor section 103 is excited and emits red light. When the laser light from the laser light source 201 is focused on the green phosphor part 104 of the phosphor wheel device 10, the green phosphor part 104 is excited and emits green light. Further, laser light from the laser light source 201 condensed on the opening 105 of the phosphor wheel device 10 passes through the rotating base 102 of the phosphor wheel device 10.

  Returning to FIG. 1, the red light and the green light obtained by the phosphor wheel device 10 are emitted from the phosphor wheel device 10 in the + Z direction. The fluorescent light emitted in the −Z direction by the red phosphor section 103 and the green phosphor section 104 is reflected by the rotating base 102 and emitted in the + Z direction. These red light and green light are collimated by the lenses 208 and 207, pass through the dichroic mirror 206, are condensed by the condenser lens 217, and enter the rod integrator 218.

  On the other hand, the blue light of the blue semiconductor laser that has passed through the opening 105 travels along the path of the lens 209, the lens 210, the mirror 211, the lens 212, the mirror 213, the lens 214, the mirror 215, and the lens 216, and is reflected by the dichroic mirror 206. Are condensed by the condenser lens 217 and enter the rod integrator 218. The lenses 212, 214, and 216 function as relay lenses.

  Light emitted from the rod integrator 218 passes through a lens 230, a lens 231, and a lens 232 of the illumination optical system 30, and a TIR (total internal reflection) prism including a pair of a first prism 233 and a second prism 234. The incident light is incident on the optical modulator 235, and the incident light is modulated by a video signal by a DMD (Digital Micromirror Device) 236, which is a light modulation element, and emitted as the video light P. The lenses 230, 231, and 232 are a lens group of a relay optical system, and have a function of forming an image of light on the emission surface of the rod integrator 218 on the DMD 236. The lens group of the relay optical system including the lenses 230, 231, and 232 is an example of a lens unit.

  The light emitted from the DMD 236 enters the projection lens 237, and the light emitted from the projection lens 237 is enlarged and projected as image light P on a screen.

[2. Configuration of main part]
The configuration of the main part of the illumination optical system 30 will be described with reference to FIGS. As shown in FIG. 3, the illumination light from the light source emitted from the rod integrator 218 is transferred by a lens group 400 including three lenses 230, 231, and 232 arranged on the optical axis, and is transferred to the first lens group. The light enters the light incident surface 233a of the prism 233, is totally reflected by a minute gap formed at the abutting portion 235a of the first prism 233 and the second prism 234, and is emitted to the DMD 236.

  A main plane 232a (shown by a broken line) of the lens 232 disposed immediately before the light incident surface 233a of the first prism 233 is inclined with respect to the optical axis L at an optical axis angle α1. Further, the light incident surface 233a of the first prism 233 is arranged to be inclined at an optical axis angle α2 with respect to the optical axis L.

  Then, an optical axis angle α1 which is an angle between the optical axis and the main plane of the lens of the lens unit disposed immediately before the light incident surface, and a light which is an angle between the optical axis and the light incident surface of the total reflection prism. The axis angle α2 has a relationship of α1 ≠ α2, and the main plane 232a of the lens 232 and the light incident surface of the first prism are arranged non-parallel. Since the lens 232 is a plano-convex lens, the main plane 232a of the lens 232 and the plane 232b of the lens 232 are in a parallel relationship. Therefore, in FIG. 3, the angle between the optical axis L and the plane 232b is defined as the optical axis angle α1. It is illustrated.

  FIG. 4 is a diagram for explaining a comparative example of the present embodiment, in which the prism shape when the light incident surface 233a of the first prism 233 is arranged perpendicular to the optical axis is indicated by a broken line in the figure. Thus, the prism area 300 is added, and the prism area 300 is larger than the prism of the present embodiment.

  In the present embodiment, the illumination optical system includes a lens unit including three relay lenses, but this lens unit may include a single lens.

[3. Effects]
In the present embodiment, the first prism 233 is smaller because there is no prism area 300 as compared with the comparative example of FIG.

  FIG. 5 is a spot diagram when light from the exit surface of rod integrator 218 is transferred onto the display surface of DMD 236 in the present embodiment. FIG. 6 is a spot diagram when the light from the exit surface of the rod integrator 218 is transferred onto the surface of the DMD 236 when the main plane 232a of the lens 232 is not inclined with respect to the optical axis and has a vertical relationship. is there.

  A comparison between FIG. 5 and FIG. 6 shows that the scatter of light converging points in the spot diagram of FIG. 5 is small, and that light is efficiently propagated.

As described above, in the present embodiment, the lens 232 is disposed so that its main plane is inclined with respect to the optical axis, and the light incident surface 233a of the first prism 233 is disposed obliquely with respect to the optical axis. By arranging the main plane 232a of the lens 232 and the light incident surface 233a of the first prism 233 in a non-parallel manner, the size of the illumination device can be reduced without lowering the light use efficiency.
The embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which changes, replacements, additions, omissions, and the like are made. Further, it is also possible to form a new embodiment by combining the components described in the above embodiment.

  The present disclosure is applicable to a projection-type image display device such as a light source device or a projector.

DESCRIPTION OF SYMBOLS 1 Projection type video display apparatus 10 Phosphor wheel apparatus 20 Light source optical system 30 Illumination optical system 101 Motor 102 Rotating base material 103 Red phosphor part 104 Green phosphor part 105 Opening 201 Laser light source 202 Collimating lens 203, 205, 207, 208, 209, 210, 212, 214, 216 Lens 232, 230, 231 Lens 232a Main plane 232b Plane 204 Diffusion plate 206 Dichroic mirror 211, 213, 215 Mirror 218 Rod integrator 233 First prism 233a Light incidence surface 234 Second Prism 235 TIR prism 236 DMD
237 Projection lens 300 Prism area 400 Lens group α1, α2 Optical axis angle

Claims (4)

A light source and a lens unit including one or a plurality of lenses disposed on the optical axis of the illumination light emitted from the light source;
A total reflection prism in which the illumination light passing through the lens unit is incident on a light incident surface,
A display element to which illumination light incident on the total reflection prism is applied,
The principal plane of the lens of the lens unit disposed immediately before the light incident surface so as to emit illumination light to the light incident surface of the total reflection prism is non-parallel to the light incident surface, and with respect to the optical axis. Lighting device that is arranged at an angle.   The illumination device according to claim 1, wherein a light incident surface of the illumination light of the total reflection prism is arranged to be inclined with respect to the optical axis.   Assuming that the angle between the optical axis and the main plane of the lens of the lens unit disposed immediately before the light incident surface is α1, and the angle between the optical axis and the light incident surface of the total reflection prism is α2, The lighting device according to claim 1, wherein α1 ≠ α2.   A projection-type image display device, comprising the lighting device according to claim 1.