JP2012013897A - Light source unit and projection-type display apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source unit that can be mounted on a projection-type display apparatus of 3-plate type which employs a phosphor as a light source, and a projection-type display apparatus employing the same.SOLUTION: In a light source unit, a semiconductor laser 1 emits exciting lights. A reflection-type color wheel 4 of a disk shape, on which red, green and blue phosphor regions are formed every prescribed angle, receives the exciting lights emitted from the semiconductor laser 1 to thereby emit red, green and blue lights as fluorescent lights. A rotation mechanism 10 causes the reflection-type color wheel 4 to rotate about the axis through the center of the disk shape at a prescribed rotating speed. A dichroic mirror 2 reflects either of the incident exciting light from the semiconductor laser 1 and the incident fluorescent light from the reflection-type color wheel 4, and transmits the other. An afocal optical system having at least each one of a positive optical member 6 and a negative optical member 5 transforms the size of a luminous flux of the fluorescent light from the reflection-type color wheel 4.

Description

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

In a projection display device such as a liquid crystal projector, a discharge lamp such as an ultrahigh pressure mercury lamp or a xenon lamp has been conventionally used as a light source. In recent years, the use of a light emitting diode or a semiconductor laser as a light source or the like has been studied in recent years.
Patent Document 1 has a plurality of fan-shaped segment regions on a circular transparent base material that can be controlled in rotation, and at least two of the segment regions of the transparent base material have excitation light emitted from a semiconductor laser. A light source device is described that includes an excitation light source in which layers of different phosphors that receive and emit light in a predetermined wavelength band are arranged and irradiates the phosphor with excitation light in the visible light region.

JP 2009-277516 A

  By the way, the light source device described in Patent Document 1 irradiates the phosphor layer with excitation light while rotating the disk-shaped transparent substrate on which the phosphor layer is formed, thereby red, green, and blue. The three primary color lights are emitted in order. Therefore, it is suitable for a field sequential color projection display device that switches the signals for the three primary colors of the display device in time sequence and correspondingly emits the three primary color lights in order, but for a three-plate projection display device. It could not be applied as it is.

  The present invention has been made in view of such problems, and provides a light source device that can be mounted on a three-plate projection display device using a phosphor as a light source, and a projection display device using the same. With the goal.

In order to solve the above-described problems of the prior art, the present invention forms a semiconductor phosphor (1), a red phosphor region, a green phosphor region, and a blue phosphor region for each predetermined angle, A disk-like reflective color wheel (4) that receives excitation light emitted from the semiconductor laser (1) and emits red light, green light, and blue light as fluorescent light, and the reflective color wheel (4) as a circle. A rotation mechanism (10) that rotates at a predetermined number of rotations about a plate-shaped center; an excitation light from the incident semiconductor laser (1); and an incident fluorescence from the reflective color wheel (4) A dichroic mirror (2) that reflects one of them and reflects the other, a positive optical member (6) that converts the size of a fluorescent light beam from the reflective color wheel (4), and a negative optical member (5 Afoka with at least one To provide a light source apparatus comprising: the optical system, the.

Said structure WHEREIN: The thermal radiation part (4b, 4c) may be formed in the surface on the opposite side to the surface into which the excitation light of the said reflection type color wheel (4) injects.
Moreover, you may make it provide the baffle part which guide | induces the cooling air at the time of the said thermal radiation part (4c) rotating to the thermal radiation part (9) adjacent to a semiconductor laser.
In addition, the light source device includes: a device (111r, 111g, 111b) that modulates light emitted from the light source device; and a projection lens (113) that projects light modulated by the device. A projection display device is provided.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the light source device which can be mounted in a 3 plate type projection type display apparatus using a fluorescent substance as a light source. In addition, a three-plate projection display device can be configured using a light source device using a phosphor as a light source.

It is a block diagram which shows the light source device of the 1st Embodiment of this invention. It is a top view which shows the structure of the light-incidence surface of the reflection type color wheel 4 shown in FIG. 3 is a cross-sectional view showing an example of a reflective color wheel 4. FIG. It is sectional drawing which shows the other example of the reflection type color wheel 4. FIG. FIG. 3 is a configuration diagram illustrating a cooling structure of the reflective color wheel 4 in the light source device according to the first embodiment of the present invention. It is a perspective view which shows the fin 4b shown in FIG. FIG. 3 is a configuration diagram showing a cooling structure of a portion including a reflective color wheel 4 in the light source device according to the first embodiment of the present invention. It is a perspective view which shows the fin 4c shown in FIG. It is a perspective view which shows the fin 4c shown in FIG. It is a figure which shows the projection type display apparatus using the light source device which concerns on 1st Embodiment.

  Embodiments of a light source device and a projection display device according to the present invention will be described below with reference to the drawings. In all the drawings, parts having common functions are denoted by the same reference numerals, and description of the parts once described is omitted.

<First Embodiment>
FIG. 1 is a configuration diagram illustrating a light source device according to a first embodiment of the present invention. The semiconductor laser 1 emits one of ultraviolet light, near ultraviolet light, and blue-violet light. Although FIG. 1 shows an example in which three CAN type semiconductor lasers are used, one or a plurality of semiconductor lasers other than three may be used. Laser light emitted from the semiconductor laser 1 is converted into substantially parallel light by the lens 1 a and travels toward the dichroic mirror 2. The dichroic mirror 2 has a characteristic of reflecting any one of ultraviolet light, near ultraviolet light, and blue-violet light that is emitted from the semiconductor laser 1 and transmitting blue light, green light, and red light having longer wavelengths than those.

  The laser light that has been made substantially parallel light by the lens 1a is reflected by the dichroic mirror 2 and turned 90 degrees, and is converged by the first convex lens 3 to be condensed at a predetermined position. A reflective color wheel 4 is disposed at a position where the laser light is condensed. The reflective color wheel 4 has a disk shape. The central portion of the reflective color wheel 4 is connected to a motor 10 as a rotating mechanism, and the reflective color wheel 4 is arranged in a rotatable state. Here, blue-violet is light having a wavelength of about 405 nm, and visible light is light having a wavelength of 410 nm to 700 nm.

  FIG. 2 is a plan view showing the structure of the light incident surface of the reflective color wheel 4. The central part of the reflective color wheel 4 is a part connected to the motor. In the peripheral portion of the reflective color wheel 4, phosphor layers 8 (8RL, 8GL, 8BL) are sequentially provided in predetermined angular units. In FIG. 2, the segment angle of the reflective color wheel 4 is set to 2 degrees. The phosphor layer 8RL is a layer including a phosphor that emits red light when excited by ultraviolet light, near ultraviolet light, or blue-violet light. The phosphor layer 8GL is a layer including a phosphor that emits green light when excited by ultraviolet light, near ultraviolet light, or blue-violet light. The phosphor layer 8BL is a layer including a phosphor that emits blue light when excited by ultraviolet light, near ultraviolet light, or blue-violet light.

  FIG. 3 is a cross-sectional view showing an example of the reflective color wheel 4. The base material 7 of the reflective color wheel 4 is made of glass or metal. FIG. 3 shows a case where the substrate 7 is a metal. As the substrate 7, at least one surface subjected to a mirror surface treatment or a mirror surface state is used. In FIG. 3, 7a indicates a mirror state. The phosphor layer 8RL, the phosphor layer 8GL, and the phosphor layer 8BL in FIG. 2 are obtained by mixing the phosphor 8R, 8G, or 8B and the binder 8b in FIG. 3 and applying them to a predetermined thickness. Here, the phosphor is applied by a precipitation method or a printing method.

  FIG. 4 is a cross-sectional view showing another example of the reflective color wheel 4. In this example, the base material 7 is glass. On one surface of the substrate 7, a reflective film 7 m such as a dichroic mirror that transmits ultraviolet light, near ultraviolet light, or blue-violet light, which is laser light, and reflects visible light is provided. On the reflective film 7m, a molded product 8a formed by mixing the phosphor 8R, the phosphor 8G, or the phosphor 8B is bonded. In the following embodiments, it is possible to arbitrarily combine whether the substrate 7 is made of metal or glass, provided by a method of applying a phosphor layer, or provided by a method of adhering a molded product.

  Returning to FIG. 1, the phosphor of the phosphor layer 8 (8RL, 8GL, 8BL) emits fluorescence upon receiving laser light as excitation light. The diffused light emitted from the phosphor is converted into substantially parallel light by the first convex lens 3, and after passing through the dichroic mirror 2, a concave lens 5 that functions as a negative optical member and a second convex lens 6 that functions as a positive optical member. The collimated light with a desired diameter is obtained. Here, the concave lens 5 and the second convex lens 6 constitute an afocal system.

The reflective color wheel 4 rotates at a rotational speed such that the three primary color lights emitted from the second convex lens 6 in time order can be regarded as white light. Generally, a frequency at which a so-called color break is not visible is assumed to be 1000 Hz or more.
The segment angle is S (degrees), the rotational speed of the reflective color wheel 4 is R (rpm), and the lighting cycle of RGB light for 1 second is X.
Since X = (R ÷ 60) × (360 ÷ (3 × S)) = (2 × R) ÷ S,
The number of revolutions where the color break is not visible is
R = (S × X) ÷ 2
It becomes. If X = 1000Hz,
R = 500 × S
It becomes.
When S = 2 degrees, R = 1000 (rpm), and when S = 8 degrees, R = 4000 (rpm).

  That is, when S = 2 degrees, the rotational speed of the reflective color wheel 4 may be 1000 (rpm) or more, and when S = 8 degrees, the rotational speed of the reflective color wheel 4 may be 4000 (rpm) or more. The rotation of the reflective color wheel 4 does not need to be synchronized with the image display period of the display element, and there is no problem even if the rotational speed of the reflective color wheel 4 is uneven. In FIG. 1, the semiconductor laser light may pass through the dichroic mirror 2 and enter the phosphor assembly 4, and the light emitted from the phosphor may reflect the dichroic mirror.

  FIG. 5 is a configuration diagram showing a cooling structure of the reflective color wheel 4 in the light source device according to the first embodiment of the present invention. Fins 4 b functioning as heat radiating portions are formed integrally with the reflective color wheel 4 on the surface opposite to the laser light incident side of the reflective color wheel 4. The reflective color wheel 4 is rotatable by a motor 10. FIG. 6 is a perspective view showing the fin 4b shown in FIG. The reflective color wheel 4 is integrally formed with fins 4 b, which are rotated by a motor 10. Since the fins 4b shown in FIG. 6 are concentric, the reflective color wheel 4 itself is cooled, but there is little diffusion of air due to centrifugal force.

  FIG. 7 is a configuration diagram showing a cooling structure of a portion including the reflective color wheel 4 in the light source device according to the first embodiment of the present invention. Fins 4 c functioning as heat radiating portions are provided on the back surface of the reflective color wheel 4. 8 and 9 are perspective views showing the fins 4c shown in FIG. These fins 4c diffuse air by centrifugal force. The reflective color wheel 4 is rotated by a motor 10 disposed at the center. The reflection type wheel 4 is covered with a duct 15 whose outer periphery functions as a wind guide portion. An incident window 15 a is provided at the laser beam incident portion of the duct 15. An air intake window 15b is provided in the vicinity of the motor 10, and a discharge window 15c is provided in the vicinity of the heat sink 9 adjacent to the semiconductor laser 1 and functioning as a heat radiating portion. As the motor 10 rotates, the cooling air 16 flows from the window 15b and cools the reflective color wheel 4 while being diffused by the fins 4c and cooling the heat sink 9 of the semiconductor laser 1 through the outer periphery of the duct 15 to discharge the window. It flows out of 15c.

A higher rotation speed of the reflective color wheel 4 is desirable for cooling, but if the rotation speed is too high, noise due to wind noise of the fins 4b increases, so it is preferable to set the rotation speed to 1800 rpm or less.

  As shown in FIG. 5, a semiconductor laser 1 that generates excitation light of ultraviolet light, near-ultraviolet light, and blue-violet light, a dichroic mirror 2, a lens 1a that condenses the excitation light emitted from the semiconductor laser 1, and an excitation A light source device including a reflective color wheel 4 having a layer containing a phosphor that emits light and a motor 10 for rotating the reflective color wheel 4, and fins 4 b are formed on the reflective color wheel 4. As a result, the cooling efficiency of the reflective color wheel 4 can be increased. Further, as shown in FIG. 7, the wind obtained by rotating the color wheel to which the fins 4c are added can be used for cooling the semiconductor laser 1 and other components. 5 and 7, since the reflective color wheel 4 is used for reflection, many fins 4b or 4c can be arranged effectively. 5 and 7, the semiconductor laser light may pass through the dichroic mirror 2 and enter the phosphor assembly 4, and the light emitted from the phosphor may reflect the dichroic mirror.

  FIG. 10 is a diagram illustrating a projection display device using the light source device according to the first embodiment. Illumination light (white light) emitted from the light source device has the light intensity distribution made uniform by the first integrator 101 and the second integrator 102, and the polarization direction is aligned in one direction by the polarization conversion element 103. In the present embodiment, the polarization direction of the light emitted from the polarization conversion element 103 is P-polarized light. The P-polarized light emitted from the polarization conversion element 103 passes through the condenser lens 104 and is separated into blue light (P-polarized light) and red-green light (P-polarized light) by the B / RG separation cross dichroic mirror 105. Blue light (P-polarized light) has its optical path bent by the mirror 106 and passes through the B field lens 109b.

  The P-polarized light that has passed through the B field lens 109b passes through a wire grid type polarization beam splitter (hereinafter referred to as “WG-PBS”) 110b, and the S-polarized component of the light modulated by the B device 111b is for B. The light is reflected by the WG-PBS 110b and travels toward the synthetic dichroic prism 112. The red / green light separated by the B / RG separation cross dichroic mirror 105 is bent in the optical path by the mirror 107 and separated by the RG dichroic mirror 108 into red light and green light. As in the case of blue light, the field lens 109r, 109g, WG-PBS 110r and 110g, and the S-polarized component of the light modulated by the devices 111r and 111g is reflected by the WG-PBS 110r and 110g and then travels to the combined dichroic prism 112. Three colors are synthesized by the synthesis dichroic prism 112 and projected onto the screen by the projection lens 113. Although the projection type display device of the above embodiment uses a reflective liquid crystal element, a transmissive liquid crystal element may be used.

1 semiconductor laser, 2 dichroic mirror, 3 first convex lens,
4 reflective color wheel,
4b, 4c fins (heat dissipating part),
5 concave lens (negative optical member), 6 second convex lens (positive optical member),
7 base material,
8 phosphor layer,
8R red phosphor, 8G green phosphor, 8B blue phosphor,
8RL red phosphor layer, 8GL green phosphor layer, 8BL blue phosphor layer,
9 heat sink, 10 motor (rotating mechanism),
15 Duct (wind guide part), 15a Incident window, 15b Air intake window,
15c spout window,
16 Cooling air,
101 first integrator, 102 second integrator,
103 polarization conversion element, 104 condenser lens,
105 B / RG separation cross dichroic mirror, 106 mirror,
107 mirror, 108 RG dichroic mirror,
109r, 109g 109b field lens,
110r, 110g, 110b WG-PBS,
111r, 111g, 111b Device 112 Synthetic dichroic prism, 113 Projection lens

Claims (4)

A semiconductor laser;
A red phosphor region, a green phosphor region, and a blue phosphor region are formed at predetermined angles, and red light, green light, and blue light are emitted as fluorescence upon receiving excitation light emitted from the semiconductor laser. A disc-shaped reflective color wheel,
A rotating mechanism for rotating the reflective color wheel at a predetermined rotational speed around a disc-shaped center;
A dichroic mirror that reflects either the excitation light from the incident semiconductor laser or the incident fluorescence emitted from the reflective color wheel;
An afocal optical system having at least one positive optical member and one negative optical member for converting the size of the fluorescent light flux from the reflective color wheel;
A light source device comprising:   The light source device according to claim 1, wherein a heat radiating portion is formed on a surface of the reflective color wheel opposite to a surface on which excitation light is incident.   The light source device according to claim 2, further comprising an air guide unit that guides cooling air generated when the heat radiating unit rotates to a heat radiating unit adjacent to the semiconductor laser. The light source device according to any one of claims 1 to 3,
A device for modulating light emitted from the light source device;
A projection lens for projecting light modulated by the device;
A projection display device comprising:

Images