JP6467916B2 - Light source device and projector provided with light source device - Google Patents

Description

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

  2. Description of the Related Art In recent years, time division projectors that take out light of a plurality of wavelengths in a time division manner and form and project an image by sequentially modulating the extracted light of the plurality of wavelengths have become widespread. As a light source device used for such a time-division projector, for example, a light source that outputs white light and a rotating wheel to which a plurality of color filters are attached are used to convert white light emitted from the light source at a constant speed. The light is made incident on a rotating wheel that rotates in order to extract light of a plurality of wavelengths (for example, blue, green, and red light) in a time-sharing manner. In addition, by using a rotating wheel (phosphor wheel) having a phosphor layer instead of a color filter, a single wavelength of light emitted from a light source such as a semiconductor laser is incident on the rotating wheel, so that a plurality of wavelengths can be obtained in a time division manner There has also been proposed a light source device for taking out the light.

  In a conventional light source device, between the light source such as a semiconductor laser and the phosphor wheel on which the light emitted from the light source is incident, the light emitted from the light source is collected and incident on the phosphor wheel. In general, a condenser lens is disposed.

  When foreign matter such as dust adheres to the surface of the condenser lens, there is a problem that the accuracy of the image projected by the projector is lowered and the brightness of the image is not uniform. For this reason, it is desirable that dust foreign matter does not adhere to the surface of the condenser lens of the light source device used in the projector.

  Static electricity is considered as one of the causes of dust adhering to the surface of the condenser lens. That is, static electricity accumulates on the surface of the condenser lens, and dust having a positive or negative charge is attracted to the surface of the lens by the static electricity, so that the dust adheres to the surface of the condenser lens.

Conventionally, the techniques described in Patent Documents 1 and 2 are known as techniques for removing static electricity accumulated in a lens.
Patent Document 1 discloses an optical lens such as a spectacle lens having an antistatic coating. The antistatic coating comprises a first layer formed from TiO ₂ and a second layer formed from Al ₂ O ₃ , wherein the first layer and the second layer are provided adjacent to each other. Has been.
Patent Document 2 discloses an optical lens such as a spectacle lens having an antistatic coating. It is disclosed that the antistatic coating is formed by a conductive transparent film such as an ITO thin film.

JP 2012-78829 A US Patent Application Publication No. 2003/0179343

  An object of this indication is to provide the light source device which can prevent that dust adheres to the surface of an optical member, and a projector provided with the light source device.

  In order to solve the above-described problem, in a light source device according to an embodiment of the present invention, a plurality of light sources, an optical member that condenses light emitted from the plurality of light sources, and the optical member are collected. A light source device that converts at least a portion of the wavelength of the light, wherein the surface of the optical member has a first region on which a conductive film is formed, and is different from the first region. The light emitted from the plurality of light sources hits the second region.

  According to the embodiments of the present invention, it is possible to provide a light source device capable of preventing dust from adhering to the surface of the optical member, and a projector including the light source device.

It is a schematic diagram which shows embodiment of the light source device which concerns on this invention. It is a schematic diagram which shows the structure of the light source with which the light source device of embodiment of this invention is provided. It is a schematic diagram which shows the structure of the fluorescent substance wheel with which the light source device of embodiment of this invention is provided. It is a side view of a condensing lens. It is the front view of a condensing lens, and is the figure which looked at the condensing lens from the side by which the some light source is arrange | positioned. It is a schematic diagram showing one embodiment of a projector according to the present invention.

Hereinafter, a light source device according to an embodiment of the present invention and a projector including the light source device will be described in detail with reference to FIGS.
As illustrated in FIGS. 1 and 2, the light source device 1 of the present embodiment includes a plurality of light sources 10, a collimator lens 20 that converts light emitted from the plurality of light sources 10 into parallel light, and a plurality of light sources 10. A condensing lens 21 for condensing the light emitted from the phosphor, a phosphor wheel 30 for converting at least a part of the wavelength of the light collected by the condensing lens 21, and a drive for rotating the phosphor wheel 30. It includes a motor 40 that is a source, and a light receiving lens 50 that receives light whose wavelength has been converted by the phosphor wheel 30 and converts the light into parallel light. The condenser lens 21 corresponds to the “optical member” in the embodiment of the present invention.

  As shown in FIG. 1 and FIG. 2, the plurality of light sources 10 includes a plurality of semiconductor lasers 11 in which a traveling direction of emitted light is perpendicular to the exit surface of the plate 12 Are held in parallel. Specifically, eight semiconductor lasers 11 are held by one plate 12, and the eight semiconductor lasers 11 and one plate are arranged so as to overlap each other. That is, the plurality of light sources 10 are configured by a total of 16 semiconductor lasers 11. The semiconductor laser 11 can be a blue semiconductor laser. The emitted light of the blue semiconductor laser 11 is, for example, light having a specific wavelength as a peak in a wavelength band of 370 to 500 nanometers, preferably having a specific wavelength as a peak in a wavelength band of 420 to 500 nanometers. Light.

The surface of the plate 12 opposite to the emission surface is connected to a heat pipe (pipe-shaped heat sink) 13, and the heat pipe 13 is further connected to a plurality of fins 14 for cooling the heat pipe 13. Further, the plurality of fins 14 are provided with suction type fans 15, and a cooling medium (for example, air) is sucked into a space between the plurality of fins 14, and the heat pipe 13 can be cooled by forced convection cooling. That is, heat generated when the semiconductor laser 11 is driven can be efficiently cooled by the cooling device having the heat pipe 13, the plurality of fins 14, and the suction type fan 15.

  As shown in FIG. 1, the condensing lens 21 condenses light emitted from the plurality of light sources 10. The light condensed by the condenser lens 21 is irradiated on the phosphor wheel 30 so as to have a predetermined spot diameter. The phosphor wheel 30 is composed of a transparent disk-shaped member that transmits light, and rotates around a rotation axis. The center of the phosphor wheel 30 is fixed to the drive shaft 40 a of the motor 40. Here, the material of the phosphor wheel 30 may be any material having a high light transmittance. For example, glass, transparent ceramics, resin, a crystal substrate such as sapphire or gallium nitride, or the like can be used.

  FIG. 3 is a front view showing the appearance of the phosphor wheel 30. 3A shows a surface on which light from a plurality of light sources 10 enters the phosphor wheel 30 (a surface viewed from the direction indicated by an arrow A in FIG. 1. Hereinafter, it is also referred to as “incident surface” or “surface”. .). FIG. 3B shows a surface from which fluorescent light is emitted from the phosphor wheel 30 (a surface opposite to the incident surface; hereinafter, also referred to as “exit surface” or “back surface”). A spot SP indicated by a broken-line circle in FIG. 3A indicates a region irradiated with light condensed by the condenser lens 21. A fluorescent region FL indicated by a broken-line circle in FIG. 3B indicates a region where a phosphor layer, which will be described later, emits light by light from the condenser lens 21.

  As shown in FIG. 3, an annular transmission region (see FIG. 3A) having a width W <b> 1 from the outer peripheral edge is provided on the incident surface of the phosphor wheel 30. This transmission region is divided into three equal parts in the circumferential direction, and three transmission regions TR1, TR2 and TR3 are provided on the same circumference. 3A illustrates an example in which each of the angle ranges of the transmission regions TR1 to TR3 is about 120 °, the angle range of each of the transmission regions is not limited to this. For example, the angle range of each of the four transmissive regions may be set to about 90 ° by dividing the transmissive region into four equal parts in the circumferential direction.

  As shown in FIG. 3A, arc-shaped dielectric films 31 each having a width W1 are formed on the incident surface sides of the transmission regions TR1 and TR2. The dielectric film 31 can transmit light emitted from the blue semiconductor laser 11 among light emitted from the plurality of light sources 10 and reflect light in other wavelength bands. As this dielectric film 31, for example, a dichroic filter can be used. On the other hand, the dielectric film 31 is not formed on the incident surface side of the transmission region TR3. For this reason, the transmission region TR3 transmits light in the entire wavelength band without attenuating light in the specific wavelength band. Further, if the transmission region TR3 only transmits light emitted from the blue semiconductor laser 11, the dielectric film 31 may be formed in the transmission region TR3. Thereby, the dielectric film 31 is formed on the entire incident surface of the phosphor wheel 30, and the dielectric film forming process can be simplified.

Next, as shown in FIG. 3B, an arcuate phosphor layer 32R having a width W2 narrower than the width W1 of the transmission region is formed on the emission surface side of the transmission region TR1. The phosphor layer 32R is excited by light emitted from the blue semiconductor laser 11 of the light source 10, and generates fluorescence having a wavelength band different from the wavelength band of the light emitted from the blue semiconductor laser 11. In other words, the phosphor layer 32R can convert the wavelength of the light emitted from the blue semiconductor laser 11. The phosphor layer 32R generates fluorescence (red light) in a wavelength band of, for example, 550 to 780 nanometers. Specific examples of the material of the phosphor layer 32R include YAG, (Sr, Ca) AlSiN ₃ : Eu, CaAlSiN ₃ : Eu, SrAlSiN ₃ : Eu, and K ₂ SiF ₆ : Mn.

In addition, an arcuate phosphor layer 32G having a width W2 is formed on the emission surface side of the transmission region TR2. The phosphor layer 32G generates fluorescence in a wavelength band different from the wavelength band of the light emitted from the blue semiconductor laser 11 as in the phosphor layer 32R. In other words, the phosphor layer 32G can convert the wavelength of the light emitted from the blue semiconductor laser 11. The phosphor layer 32G generates fluorescence (green light) in a wavelength band of, for example, 500 to 650 nanometers by light emitted from the blue semiconductor laser 11. As an example of a specific material of the phosphor layer 32G, an oxide-based phosphor such as β-SiAlON: Eu, Lu ₃ Al ₅ O ₁₂ can be given.

  A phosphor layer is not formed on the emission surface side of the transmission region TR3. For this reason, the transmission region TR3 can transmit light in the entire wavelength band. However, speckle noise may be reduced by forming a scattering surface in the transmission region TR3 and dynamically diffusing the blue light emitted from the light source 10 by the rotation of the phosphor wheel 30.

  As shown in FIG. 1, the motor 40 is a brushless DC motor, and is fixed so that the drive shaft 40 a is orthogonal to the surface of the phosphor wheel 30. The motor 40 rotates the phosphor wheel 30 in the direction indicated by the arrow B in FIG. 3 at a rotation speed based on the frame rate of the moving image to be reproduced (the number of frames per second. The unit is [fps]). For example, when playing a moving image of 60 [fps], it is preferable to set the rotation speed of the phosphor wheel 30 to an integral multiple of 60 rotations per second.

  The light receiving lens 50 is an optical member that condenses light emitted from the phosphor layers 32R and 32G. That is, the light receiving lens 50 condenses the fluorescence generated in the phosphor layers 32R and 32G by the light emitted from the plurality of light sources 10 and emits it as the emitted light of the light source device 1.

  In the light source device 1 having the above-described configuration, light emitted from the plurality of blue semiconductor lasers 11 is collected by the condenser lens 21. The light condensed by the condenser lens 21 is irradiated on the phosphor wheel 30. The phosphor wheel 30 is rotated by the motor 40 in the direction of arrow B in FIG. The light condensed by the condenser lens 21 hits the spot SP on the incident surface of the phosphor wheel 30. When the spot SP is positioned on the transmission region TR1, the light collected by the condenser lens 21 enters the phosphor layer 32R, and the red light is emitted to the light receiving lens 50. Further, when the spot SP is located on the transmission region TR2, the light collected by the condenser lens 21 enters the phosphor layer 32G, and the green light is emitted to the light receiving lens 50. Furthermore, when the spot SP is positioned on the transmission region TR3, the phosphor layer is not formed, and thus incident blue light is emitted to the light receiving lens 50.

  In this manner, the light source device 1 repeatedly emits red, green, and blue light in order according to the rotation of the phosphor wheel 30.

FIG. 4 is a side view of the condenser lens 21. FIG. 5 is a front view of the condensing lens 21 and is a view of the condensing lens 21 from the side where the plurality of light sources 10 are arranged.
As shown in FIGS. 4 and 5, the condensing lens 21 is a substantially circular glass or plastic lens having a predetermined thickness, and a peripheral portion thereof is held by a metal holder 60. The holder 60 is fixed to the upper surface of the housing 70 of the light source device 1.

  As shown in FIG. 4, the light emitted from the plurality of light sources 10 is converted into parallel light by the collimator lens 20 and then enters the surface (incident surface 21 a) of the condenser lens 21. The light incident on the incident surface 21 a of the condenser lens 21 is refracted on the incident surface 21 a of the condenser lens 21 and the exit surface 21 b which is the opposite surface, and then travels toward the focal point FP of the condenser lens 21. Then, the position of the condenser lens 21 is adjusted so that the focal point FP of the condenser lens 21 coincides with the spot SP on the incident surface of the phosphor wheel 30 described above. Thereby, the condensing lens 21 can condense the light emitted from the plurality of light sources 10 and make it incident on the spot SP of the phosphor wheel 30.

  As shown in FIGS. 4 and 5, a conductive film 62, which is a film that can conduct electricity, is formed on the incident surface 21 a and the emission surface 21 b of the condenser lens 21. The peripheral edge of the conductive film 62 is in contact with a metal holder 60 that holds the condenser lens 21. Thereby, the conductive film 62 is electrically connected to the metal holder 60.

  The conductive film 62 can be formed of a metal film, for example. When the conductive film 62 is formed of a metal film, for example, copper or aluminum can be used as the material of the metal film. The metal film can be formed on the surface of the condenser lens 21 by using, for example, a sputtering method or a vapor deposition method. The conductive film 62 only needs to be a film that can conduct electricity, and can be formed of a transparent conductive film such as an ITO film or a film made of a conductive resin in addition to a metal film.

  Hereinafter, a region where the conductive film 62 is formed on the incident surface 21a and the emission surface 21b of the condenser lens 21 is referred to as a “first region 62a” and is a region other than the first region 62a. Is referred to as "second region 62b".

As shown in FIG. 5, the second region 62b in which the conductive film 62 is not formed is formed by a total of 16 regions each having a circular shape. The first regions 62a where the conductive film 62 is formed are formed between and around the second regions 62b, which are a total of 16 circular regions.
The shape of the second region 62b where the conductive film 62 is not formed is not limited to a circle, and may be an ellipse equivalent to the beam shape of the semiconductor laser, for example.

  As described above, the plurality of light sources 10 includes 16 blue semiconductor lasers 11. The light emitted from the 16 blue semiconductor lasers 11 strikes only the second region 62b, which is a total of 16 circular regions, out of the incident surface 21a and the exit surface 21b of the condenser lens 21. In other words, the second area 62b is formed only in the area where the light emitted from the plurality of light sources 10 (16 laser light sources 11 in total) strikes among the incident surface 21a and the emission surface 21b of the condenser lens 21. Yes.

  By configuring the second region 62b in this way, even when the conductive film 62 is formed on the incident surface 21a and the emission surface 21b of the condenser lens 21, the plurality of light sources 10 are formed by the conductive film 62. Therefore, the amount of light emitted from the light source device 1 can be prevented from decreasing.

  In addition, a conductive film 62 is formed in a first region, which is a region where light emitted from the plurality of light sources 10 does not strike, on the incident surface 21 a and the emission surface 21 b of the condenser lens 21. With the conductive film 62, static electricity accumulated inside or on the surface of the condenser lens 21 can be efficiently released. That is, static electricity accumulated in or on the surface of the condenser lens 21 can be released to the outside through the conductive film 62 and the metal holder 60 that can conduct electricity.

  When the casing 70 of the light source device 1 is formed of a metal such as iron or aluminum, the metal holder 60 is fixed to the upper surface of the casing 70, so that the inside or the surface of the condenser lens 21. The static electricity stored in can be released to the outside of the light source device 1 through the housing 70. In this case, the housing 70 is preferably connected to the ground.

  According to the light source device 1 according to the present embodiment, static electricity accumulated inside or on the surface of the condenser lens 21 can be efficiently released to the outside. Therefore, it is possible to prevent the dust from being attracted by static electricity, so that it is possible to effectively prevent the dust from adhering to the surface of the condenser lens 21.

  In the above embodiment, an example in which light emitted from the plurality of light sources 10 is collected by the condenser lens 21 has been described, but the present invention is not limited to such an embodiment. For example, the optical member for collecting the light emitted from the plurality of light sources 10 may be a mirror (for example, a concave mirror).

  When the light emitted from the plurality of light sources 10 is collected by a mirror, a conductive film 62 is formed on the surface of the mirror. In this case, like the above-described condenser lens 21, the conductive film 62 is formed in the first region on the surface of the mirror, and the conductive film 62 is not formed in the second region different from the first region. As shown in FIG. 5, the mirror surface is similar to the surface of the condensing lens 21 in that it includes a second region surrounded by the first region where the conductive film is formed and 16 conductive films are not formed. It can be explained by using. And the electrically conductive film 62 is formed so that the light emitted from the several light source 10 may hit only a 2nd area | region. Accordingly, static electricity accumulated inside or on the surface of the mirror can be released, so that dust can be prevented from adhering to the surface of the mirror.

(Application example of light source device 1)
Next, a schematic configuration when the light source device 1 shown in FIG. 1 is used as a light source device in a so-called one-chip DLP (Digital Light Processing) projector will be described with reference to FIG. In FIG. 6, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the projector 100 shown in FIG. 6, the light emitted from the light source device 1 is reflected by a DMD (Digital Micromirror Device) element 110 that is a light modulation unit, is condensed by a lens 120 that is a projection unit, and is collected on a screen S. Projected. The DMD element 110 is an array of fine mirrors corresponding to each pixel of an image projected on the screen S. The light emitted to the screen S by changing the angle of each mirror is converted in units of microseconds. Can be turned on / off. Here, when the angle of the mirror is such that the light emitted from the light source device 1 is reflected to the lens 120, the mirror is turned on, and when the mirror is not reflected to the lens 120, the mirror is turned off.

  Further, the gradation based on the image data of the image to be projected is changed by changing the gradation of the light incident on the lens 120 according to the ratio of the time during which each mirror of the DMD element 110 is turned on to the time when the mirror is turned off. Display is possible. As a result, color images (including moving images) are projected onto the screen S by performing gradation control with individual mirrors for each of red light, green light, and blue light sequentially emitted from the light source device 1. can do. The lens 120 is mainly composed of a projection lens, and projects an image formed by the DMD element 110 onto the screen S after being enlarged to a predetermined size.

  In the present embodiment, the DMD element is used as the light modulation means. However, the present invention is not limited to this, and any other light modulation element can be used depending on the application. Further, the light source device according to the embodiment of the present invention and the projector using the light source device are not limited to the above-described embodiments, and various other embodiments are included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Light source device 10,10 ', 10 "Light source 11 Blue semiconductor laser 12 Plate 13 Heat pipe 14 Fin 15 Fan 20 Collimating lens 21 Condensing lens (optical member)
30 phosphor wheel 31 dielectric film 32R, 32G phosphor layer 40 motor 40a drive shaft 50 light receiving lens 60 holder 62 conductive film 62a first region 62b second region 70 housing 100 projector 110 DMD element (light modulation means)
120 lens (projection means)

Claims (7)

Multiple light sources;
An optical member for condensing light emitted from the plurality of light sources at one point ;
A phosphor wheel that converts the wavelength of at least part of the light collected by the optical member, and a light source device comprising:
The incident surface and the emission surface of the optical member have a first region where a conductive film is formed, and light emitted from the plurality of light sources hits a second region different from the first region,
The light source apparatus according to claim 1, wherein the second region has a plurality of shapes corresponding to beam shapes of the plurality of light sources.   The light source device according to claim 1, wherein the optical member is a lens.   The light source device according to claim 1, wherein the optical member is a mirror.   The light source device according to claim 1, wherein the conductive film is a metal film.   The light source device according to claim 1, wherein the conductive film is electrically connected to a metal holder that holds the optical member. The beam shape of the plurality of light sources is an elliptical shape,
The light source device according to claim 1, wherein a shape of the second region is an elliptical shape. The light source device according to any one of claims 1 to 6 ,
A light modulation unit that sequentially modulates light of a plurality of wavelength bands emitted from the light source device to form an image based on image data;
Projection means for enlarging and projecting the image;
With projector.