JP2011133899A - Light guide apparatus and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide apparatus that can take in more optical fluxes emitted from a light source and can emit an optical flux gently angled with the optical axis rather than large angled, and also to provide a projector using this light guide apparatus. <P>SOLUTION: The light guide apparatus 224 includes: a hollow cylindrical light tunnel 240 having an externally rectangular shape; and a glass rod 242. The light tunnel 240 makes an incident port 246 at one end of the opening and an exiting port 247 at the other end, having a reflection area 241 on the inner surface, with the inner space made as a light guide. The glass rod 242 has a flaring slope 243 from the incident port 246 end to the exiting port 247, wherein the slope 243 is arranged inside the light guide of the light tunnel 240, making the bottom of the glass rod 242 be a light emitting port. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light guide device and a projector using the light guide device.

  Today, data projectors are widely used as image projection apparatuses that project screen display images, video images, and the like of personal computers onto a screen. This projector uses a high-intensity light source, and a lamp unit in which a concave reflecting mirror as a reflector is attached to a small high-intensity discharge lamp such as a metal highland lamp or an ultra-high pressure mercury lamp is incorporated in the projector as a projector light source device. There are many cases.

  In this lamp unit, a rotating parabolic reflector or a rotating ellipsoidal reflector is often used. A high-intensity discharge lamp is installed at the elliptical focal point of the reflector and emitted toward the front and rear. The reflected light is reflected by the rotating parabola or the ellipsoidal reflector and condensed on a light guide device such as a light tunnel or a light guide rod.

  The light from the light source device incorporating a high-intensity discharge lamp such as an ultra-high pressure mercury lamp is composed of a red filter, a green filter, and a blue filter, and is red using a color wheel that rotates at a rotation speed of 120 times per second, The green, blue light is passed through the light guide rod and the like, and then condensed by a lens onto a micromirror display element generally called DMD. A color image is displayed on the screen according to the amount of light in the on state reflected toward the projection port.

  Here, DMD means that a minute mirror cell is swung by a control signal, the direction of reflected light is controlled, and the light incident on the display element is reflected by the light source side optical system in the direction of the projection lens which is the projection side optical system. The on-state light and the off-state light reflected in the direction of the light absorbing plate are used, and the color image is projected onto the screen by controlling the time during which the red, green, and blue light is turned on.

  The light source side optical system of such a projector is composed of a light source device including a reflector that collects light, a color wheel, a light guide device such as a light tunnel and a light guide rod that makes light uniform, and a light source side lens group. ing.

  With regard to this light guide device, many inventions have been made in order to emit light in a more uniform manner. For example, in Japanese Patent Application Laid-Open No. 2003-57514, a light guide device is proposed in which a hollow rectangular cylindrical body having an inner surface as a reflecting surface is combined in the vicinity of an emission port of a solid glass rod that is a rectangular column. . In this proposal, it is possible to make the light flux density uniform while suppressing the attenuation of the light amount by the light guide device for the light incident at various angles.

JP 2003-57514 A

  In a conventional light guide device, a projection lens due to the aperture ratio of a projection lens such as a light source side lens group for irradiating light to the display element or a projection side optical system that projects light reflected by the display element on a screen. Since there is a limit to the angle of the illumination light beam that can be captured in the light beam, a combination of optical systems after the light guide device is required to use a light beam having a large angle with the optical axis out of the light beam emitted from the end face of the light guide device. There is a problem that it becomes complicated and becomes a useless ray bundle that cannot be actually used.

  The present invention has been made in view of the problems of the prior art as described above, and takes in more light bundles emitted from the light source device, and light bundles having a large angle with the optical axis are also light rays with a moderate angle. An object of the present invention is to provide a light guide device that can emit light as a bundle from a light exit and a projector using the light guide device.

  The light guide device (224) of the present invention includes a cylindrical light tunnel (240) having a rectangular parallelepiped outer shape and a hollow inside, and a glass rod (242), and the light tunnel (240) has one end of an opening. Is the incident port (246), the other end is the exit port side end (247), the inner surface has a reflective surface (241) and the inner space is a light guide, and the glass rod (242) is on the incident port (246) side From the exit side end (247) side of the glass rod (242) by placing the inclined portion (243) in the light guide path of the light tunnel (240). It is a light exit.

The inclined portion (243) is symmetrical with respect to the horizontal plane including the optical axis and symmetrical with respect to the vertical plane including the optical axis.
Also, the glass rod (242) may have a prismatic part (244) at the bottom of the inclined part (243), and the reflecting surface (241) in the light tunnel (240) is inclined from the entrance (246) side. It may be formed in the middle of the part (243).

Furthermore, the glass rod (242) has a quadrangular pyramid shape, is arranged so that the central axis is located on the optical axis, the upper surface is arranged substantially on the same plane as the entrance (246), and the bottom surface is a light tunnel. It may be arranged on substantially the same plane as the exit opening side end (247) of (240), and its bottom surface may have the same size as the exit opening side end (247) of the light tunnel (240).
In addition, the vicinity of the end of the inclined portion on the incident port (246) side may be a tip portion (245) having a large inclination angle.

  The projector of the present invention includes a light source device (210), a light source side optical system (220), a display element (230) that generates a projection image, a projection side optical system (250) that projects the projection image, Projector control means (181), the light source side optical system (220) includes a color wheel (221), a light guide device (224), a light source side lens group (226), and a mirror (228). As the light guide device (224), a combination of various glass rods (242) and a light tunnel (240) as described above is used.

  According to the present invention, a light bundle that takes in a light bundle emitted from a light source device, and a light bundle having a large angle with the optical axis can be emitted from a light exit as a light bundle having a gentle angle. It is possible to efficiently irradiate the transmitted light to the display element and to provide a projector capable of projecting a bright image.

1 is a perspective view of a projector according to the present invention. The top view which removed the upper surface of the projector which concerns on this invention. The perspective view which shows the Example whose front-end | tip of the glass rod of the light guide device which concerns on this invention is a point. The perspective view which shows the Example whose front-end | tip of the glass rod of the light guide device which concerns on this invention is linear. The figure which shows typically the reflective path | route of the light guide device which concerns on this invention. The perspective view which shows the other example whose front-end | tip of the glass rod of the light guide device which concerns on this invention is a point. The perspective view which shows the other example whose front-end | tip of the glass rod of the light guide device which concerns on this invention is linear. The perspective view which shows the other shape of the glass rod of the light guide apparatus which concerns on this invention. The perspective view which shows the further another shape of the glass rod of the light guide apparatus which concerns on this invention. The perspective view which shows another shape of the glass rod of the light guide apparatus which concerns on this invention. The perspective view which shows another shape of the glass rod of the light guide apparatus which concerns on this invention. The perspective view which shows the shape which used the front-end | tip of the glass rod of the light guide device which concerns on this invention as the surface.

  The projector 100 according to the best mode for carrying out the present invention includes a light source device 210, a light source side optical system 220, a display element 230 that generates a projection image, a projection side optical system 250 that projects the projection image, and a projector. The light source side optical system 220 includes a color wheel 221, a light guide device 224, a light source side lens group 226, and a mirror 228.

  The light guide device 224 includes a cylindrical light tunnel 240 having a rectangular parallelepiped outer shape and a hollow inside, and a glass rod 242. The light tunnel 240 emits one end of the opening at the entrance 246 and the other end. The mouth side end 247 has a reflection surface 241 on the inner surface, and the inner space serves as a light guide path.

  Further, the glass rod 242 has an inclined portion 243 that widens toward the exit end 247 from the entrance 246 side, and is inclined in the light guide path of the light tunnel 240 so that the central axis is located on the optical axis. The portion 243 is disposed, the tip of the glass rod 242 is disposed on substantially the same plane as the incident port 246, and the bottom surface is disposed on substantially the same plane as the exit port end 247.

  According to this best mode, the light beam emitted from the light source device is captured, and the light beam having a large angle with the optical axis is also emitted from the bottom surface of the glass rod as the light exit port as a light beam having a gentle angle. The projector can be provided with a light guide device capable of forming a bright projection image.

  The projector according to the present invention has a built-in microcomputer as a projector control means, and has a projection port 123 having a lens cover 121 on the front panel 120 of a case that is a substantially rectangular parallelepiped as shown in FIG. On the top panel 110 of the case are keys and indicators such as a power switch 111, manual image quality adjustment key 113, automatic image quality adjustment key 114, power lamp indicator 112, light source lamp indicator 115, overheat indicator 116, and speaker inside. It has a loudspeaker hole 118 and an open / close lid 119, and a back panel (not shown) has various signal input terminals such as a power connector, a USB terminal connected to a personal computer, a video terminal for inputting image signals, and a mini D-sub terminal. A projector 100 having

  The upper lid 119 has subkeys for fine adjustment of image quality and image and various operation settings of the projector 100. An intake port is provided on the left side panel of the case and an exhaust port is provided on the right side panel 140. A port 145 is provided and has a cooling fan inside.

  In addition, the front panel 170 has a forefoot member 170 that can adjust the amount of protrusion at the front of the bottom panel, and a fixed rear foot member 175 at the rear left and right of the bottom panel. By changing the front height of the projector 100, it is possible to project an image according to the height of the screen.

  In the projector 100, as shown in FIG. 2, a light source device 210 incorporating a discharge lamp 211 such as an ultra-high pressure mercury lamp, and a color wheel 221 and a light guide device 224 as a light source side optical system 220, The illumination side optical system has a plurality of light source side lens groups 226 and one mirror 228.

  Furthermore, the circuit board 180 to which the lamp power supply circuit 187 and the projector control means 181 are attached, the light source side optical system 220 that irradiates the display element 230 with the light emitted from the light source device 210, and the plurality of pixels in the row direction and the column direction. A display element 230 that displays an image by controlling the reflection of incident light arranged in a matrix, and a projection-side optical system 250 that projects light emitted from the display element 230 onto a projection surface such as a screen. The projector 100 incorporates a lens group 253 and a movable lens group 255.

  The circuit board 180 is provided with a projector control means 181 by a microcomputer. The control means 181 controls the operation of each circuit in the projector. When the power switch 111 is turned on, the discharge of the light source device 210 is performed. The lamp 211 is turned on, and the cooling fan 190 is driven at a rated speed according to the output of the discharge lamp 211 and the fan shape and arrangement of the cooling fan 190. The projector 100 is put into a standby state while the air inside the panel 140 is exhausted from the exhaust port 145.

When the temperature of the discharge lamp 211 rises to a predetermined temperature and the light emission is stabilized, an image can be projected by inputting an image signal.
In addition, when the power switch 111 is turned off, the discharge lamp 211 is turned off, and the cooling fan 190 is continuously driven for a predetermined time of about several minutes by a timer to cool the inside of the projector 100 and then perform all operations. Control such as stopping is also performed.

  The display element 230 is a display element 230 having no means for coloring incident light such as a color filter. In this embodiment, a micromirror display element generally abbreviated as DMD (Digital Micromirror Device) is used. Yes. The horizontal to vertical ratio of the micromirror display element is usually 4: 3.

  The micromirror display element is configured to convert light incident from an incident direction inclined in one direction with respect to the front direction into an on-state light beam in a front direction and an off-state light beam in an oblique direction by switching the tilt directions of the plurality of micromirrors. The light is incident on the micromirror tilted in one tilt direction and turned into an on-state light beam reflected in the front direction by this micromirror, and tilted in the other tilt direction. The light incident on the micromirror is reflected off-axis by the micro-mirror to form an off-state light beam, and the off-state light beam is absorbed by the light-absorbing plate. The image is displayed by dark display by reflection of the light.

  The light source device 210 includes a discharge lamp 211 inside, and an elliptical spherical reflector whose inner surface is a reflecting surface, and an explosion-proof surface is installed in front of the reflector so as to close the opening in front of the reflector. The discharge lamp 211 is connected by a conductive wire so that power can be supplied from the lamp power supply circuit 187, and the discharge lamp 211 emits light and is reflected by the reflecting surface of the reflector to irradiate light in front of the light source device 210. .

  The light source side optical system 220 that makes the light emitted from the light source device 210 enter the micromirror display element 230 includes a color wheel 221, a light guide device 224, a light source side lens group 226 that is a plurality of lenses, and a mirror 228. It consists of. The color wheel 221 has a thin disk shape and has a color filter on the plane for sequentially coloring the light emitted from the light source device 210.

  The light guide device 224 is disposed at a position where the incident surface faces the exit side of the color wheel 221, and guides the light incident from the incident port while reflecting the light from the reflection surface on the inner peripheral surface of the light guide device 224. The light is emitted from the injection port as light having a uniform intensity distribution.

  The mirror 228 of the light source side optical system 220 reflects the light emitted from the light source device 210 and transmitted through the color wheel 221, the light guide device 224, and the light source side lens group 226 toward the display element 230. Light is projected onto the display element 230 from a direction inclined in one direction with respect to the front direction.

  The projection-side optical system 250 includes a fixed lens barrel that contains a fixed lens group 253, and a movable lens group 255 that is engaged with the fixed lens barrel and that can move forward and backward in the axial direction by a rotating operation. The projection-side optical system 250 includes a lens barrel and forms a zoom lens by a combination of a plurality of lenses incorporated in these lens barrels.

  As described above, the projector 100 emits light from the light source device 210 in one direction, and rotates the color wheel 221 of the light source side optical system 220 at a high speed, thereby entering the light source side optical system 220 from the light source device 210. The colored light is sequentially colored by the color wheel 221, and the intensity distribution is made uniform by the light tunnel 240 of the light guide device 224, and directed to the display element 230 by the light source side lens group 226 and the mirror 228 as the light source side optical system 220. Project.

  When the light from the light source device 210 is stabilized after a predetermined time has elapsed since the power was turned on, the monochrome image of each color is displayed on the display element 230 in synchronization with the projection period of each colored light transmitted through the color wheel. By sequentially writing the data, the single color image of each color is sequentially formed on the display element 230 by the on-state light beam reflected in the front direction of the display element 230, and the single color image light of each color sequentially emitted from the display element 230 is projected on the projection side. The image is magnified by the lens groups 253 and 255 of the optical system 250 and projected onto the projection surface, and a full-color image in which the single-color images of the three colors are superimposed is displayed on the projection surface.

  As shown in FIGS. 3 and 4, the light guide device 224 of the present embodiment has a cylindrical light tunnel 240 whose outer shape is a rectangular parallelepiped shape, and whose inside is also a rectangular parallelepiped cavity, and a light tunnel 240. And a glass rod 242 having a refractive index larger than that of air.

The light tunnel 240 has a rectangular parallelepiped outer shape and a hollow hollow inside, and has an opening 246 at one end of the opening, an exit end 247 at the other end, and a reflecting surface 241 on the inner surface. In addition, the internal space is used as a light guide path by forming the reflection surface 241 on the inner surface.
In addition, the opening portions at both ends of the light tunnel 240 are formed at a ratio of approximately 4: 3, in the same manner as the horizontal / vertical ratio of the micromirror display element, in order to emit a light beam that matches the shape of the micromirror display element. ing.

The glass rod 242 has a shape having an inclined part 243 that widens toward the exit side end 247 from the incident port 246 side, and the inclined part 243 is disposed in the light guide path of the light tunnel 240. is there.
The inclined portion 243 is shaped vertically symmetrical with respect to the horizontal plane including the optical axis and symmetrical with respect to the vertical plane including the optical axis.

  The glass rod 242 of the light guide device 224 shown in FIG. 3 has a quadrangular pyramid shape, and the bottom surface is formed in the same shape with the same size as the light exit side end 247 of the light tunnel 240. The central axis of the glass rod 242 is located on the optical axis of the emitted light, the tip of the glass rod 242 is located on the substantially same plane as the incident port 246, and the bottom surface is located on the same plane as the exit side end 247. The length from the entrance 246 to the exit end 247 of the light tunnel 240 and the height from the bottom to the tip of the glass rod 242 are the same.

  Further, the glass rod 242 of the light guide device 224 shown in FIG. 4 has an angle at which the upper and lower inclined surfaces of the inclined portion 243 of the glass rod 242 intersect the optical axis, and the left and right inclined surfaces of the inclined portion 243 of the glass rod 242 are the optical axes. All of the angles intersecting with are formed as the same angle, and the tip of the glass rod 242 has a linear shape extending sideways.

  Then, the central axis of the glass rod 242 is positioned on the optical axis of the light emitted from the light source device 210, the tip of the glass rod 242 is disposed on substantially the same plane as the entrance 246, and the bottom is the exit side end 247. They are arranged on substantially the same plane, and the length from the entrance 246 to the exit end 247 of the light tunnel 240 and the height from the bottom to the tip of the glass rod 242 are substantially the same.

  Compared with the glass rod 242 shown in FIG. 3, the tip of the glass rod 242 has the same opening angle as the glass rod 242 shown in FIG. The angle of diffusion of the light beam emitted in the vertical direction of the glass rod 242 and the light beam emitted in the horizontal direction can be made the same.

  In the light guide device 224 in which the glass rod 242 having the inclined portion 243 as described above is inserted into the light tunnel 240, as shown in FIG. 5, incident light incident from the incident port 246 is firstly inclined portion of the glass rod 242. The incident light beam is refracted and enters the inclined portion 243, and light having a large opening angle with the optical axis is emitted from the other inclined surface. At this time, since the refractive index of the glass rod 242 is larger than that of air, the angle formed by the optical axis and the light beam is larger than the opening angle with respect to the optical axis of the light incident on the inclined portion 243 with respect to the optical axis of the light emitted from the inclined portion 243. The opening angle becomes smaller.

The light transmitted through the inclined portion 243 of the glass rod 242 is reflected by the reflecting surface 241 and is incident on the inside of the inclined portion 243 again from the inclined surface of the inclined portion 243 of the glass rod 242.
As described above, the light transmitted through the glass rod 242 has a smaller opening angle with respect to the optical axis while repeatedly entering and exiting the glass rod 242, and the light that has entered the glass rod 242 is critical to the slope of the inclined portion 243. A corner is reached and total reflection occurs inside the glass rod 242.

Then, the angle formed by the optical axis is further reduced by total reflection, and is emitted to the outside from the bottom surface of the glass rod 242.
In addition, light that has a small angle with the optical axis of the light beam incident from the entrance 246 by repeating total reflection on the inclined surfaces facing each other in the inclined portion 243 of the glass rod 242 is reduced with respect to the size of the opening. The longer the length of 242 is, the greater the effect of reducing the angle with the optical axis.

  Further, a light beam having a gentle incident angle is transmitted a few times through the inclined portion 243, and has a superimposing effect of reducing the light amount loss because it starts total reflection relatively near the entrance 246, that is, in a thin portion of the glass rod 242.

  In order to reduce the angle of the incident light beam on the exit side, the reflection surface of the light tunnel 240 is widened so that the incident surface side of the light tunnel 240 is reduced without using the glass rod 242 as in this embodiment. However, since the area of the entrance 246 that takes in the incident light beam is reduced, the size of the entrance 246 becomes smaller than the size of the light beam emitted from the reflector of the light source device 210, and the light guide A light flux that cannot be taken into the device 224 is generated, and a light flux that cannot be used is generated, so that the effective light flux does not increase as a result.

  Then, in the light guide device 224 in which the glass rod 242 provided with the inclined portion 243 is arranged in the light tunnel 240, all the light beams incident on the light guide device 224 reach the critical angle of the glass rod 242 and start total reflection. After that, since light does not leak to the outside of the glass rod 242, the reflection surface 241 in the light tunnel 240 becomes unnecessary after all incident light starts total reflection inside the glass rod 242.

  Therefore, as shown in FIGS. 6 and 7, a reflecting surface 241 in the light tunnel 240 formed between the entrance 246 side and the middle of the inclined portion 243 can be used, and the central axis of the glass rod 242 can be used. Is arranged in the light guide path of the light tunnel 240 so as to be on the optical axis line, and the fixture of the glass rod 242 is installed in a portion where the reflection surface 241 of the light tunnel 240 is not formed, or the reflection surface 241 The light tunnel 240 is formed over the entire length of the light tunnel 240 and is shorter than the glass rod 242. The glass rod 242 and the light tunnel 240 can be supported by individual support tools.

  By using such a light guide device 224, incident light having a large angle with the optical axis can be emitted from the light exit opening on the bottom surface of the glass rod 242 with a small angle with the optical axis in the light guide path. In addition, incident light having a small angle with the optical axis can start total reflection earlier, reduce reflection on the inner surface of the light tunnel 240, and increase the efficiency of the light quantity uniformity effect emitted from the light exit. .

  Further, as another shape of the light guide device 224, as shown in FIGS. 8 and 9, the light tunnel 240 has an inner portion of the light tunnel 240 at the exit side end of the inclined portion 243 of the glass rod 224 shown in FIGS. What formed the square pillar part 244 substantially the same shape as shape can also be used.

  Here, in both the light guide devices 224 shown in FIGS. 8 and 9, the tip of the glass rod 242 is disposed on substantially the same plane as the entrance 246 of the glass tunnel 240, and the bottom surface of the prism portion 244 is emitted from the light tunnel 240. Although it is positioned substantially on the same plane as the mouth side end 247, the bottom surface of the glass rod 242 may be protruded from the exit side end 247.

  By forming the glass rod 242 from the inclined portion 243 and the prismatic portion 244 in this way, a contact surface between the inner surface of the light tunnel 240 and the glass rod 242 is secured, and the light tunnel 240 and the glass rod 242 are fixed. It can be strong.

  Even when such a light guide device 224 is used, since the glass rod 242 has the inclined portion 243 that spreads from the entrance port 246 side toward the exit port side end 247 side, the light guide device 224 described above. In the same manner as above, incident light having a large angle with the optical axis can be emitted from the bottom surface of the glass rod 242 with a small angle with the optical axis in the light guide, and incident light having a small angle with the optical axis can be emitted. There is also an effect that the number of reflections is reduced, and the efficiency of the light quantity uniformity effect emitted from the light exit is increased. Further, since the prism 244 is provided at the bottom of the inclined portion 243 of the glass rod 242, the glass rod 242 and the light The attachment strength with the tunnel 240 is also increased.

Further, as shown in FIGS. 10 and 11, as the light guide device 224 including the glass rod 242 of another shape, the vicinity of the end portion on the incident port 246 side of the inclined portion 243 is formed as a tip portion 245 having a large inclination angle. Some will do.
This light guide device 224 is also arranged in the light guide path of the light tunnel 240 so that the central axis of the glass rod 242 is located on the optical axis, and the tip of the glass rod 242 is substantially flush with the entrance 246 of the light tunnel 240 The bottom surface is disposed on substantially the same plane as the emission port side end 247.

  According to the light guide device 224 having such a shape, the light incident from the incident port 246 first enters the tip portion 245 having a large inclination angle, and the angle formed with the optical axis is rapidly converted by the tip portion 245. After that, the angle formed with the optical axis is made gentle by the inclined portion 243 having a gentle inclination angle, and the light bundle is made uniform, and this uniform light bundle is emitted from the light exit port which is the bottom surface of the glass rod 242. Is done.

  Even when the light guide device 224 having such a shape is used, the glass rod 242 has the inclined portion 243 that spreads from the incident port 246 side toward the output port side end 247 side. Similar to the light guide device 224, incident light having a large angle with the optical axis can be emitted from the light exit port with a small angle with the optical axis in the light guide path, and also with a small angle with the optical axis. Incident light has the effect of reducing the number of reflections on the inner surface of the light tunnel 240 and increasing the efficiency of the uniform amount of light emitted from the light exit. Further, since the inclined portion 243 and the tip portion 245 having a large inclination angle are provided, incident light having a large angle with the optical axis can be quickly converted into a gentle angle.

  The glass rod 242 shown in FIG. 10 has a sloped portion 243 and a tip portion 245 both of which are formed as slopes having a quadrangular pyramid shape, and the glass rod 242 shown in FIG. Are the same, and the angles at which the top, bottom, left and right inclined surfaces of the tip 245 intersect the optical axis are also the same.

Furthermore, as another shape of the light guide device 224, as shown in FIG. 12, a glass rod having a quadrangular pyramid shape disposed inside the light tunnel 240 described above can be used.
Here, the upper surface of the glass rod 240 is disposed substantially on the same plane as the incident port 246 of the glass tunnel 240, and the bottom surface is disposed on substantially the same plane as the emission port side end 247.
Incidentally, the shape of the tip is shaped so that the ratio of horizontal to vertical is approximately 4: 3, similar to the shape of the micromirror display element.

  In this way, by using the glass rod 242 having a truncated pyramid shape, the tip is less likely to break than the glass rod 242 having a sharp tip or a linear shape as described above, and the tip is flat. Therefore, safety is also improved. Furthermore, since the tip is a flat surface, the manufacture is facilitated.

  Even when the light guide device 224 having such a shape is used, the glass rod 242 has the inclined portion 243 that widens toward the exit port side end 247 from the entrance port 246 side. Similar to the optical device 224, incident light having a large angle with the optical axis can be emitted from the light exit through a small angle with the optical axis in the light guide.

  Incidentally, the glass rod 242 of each embodiment shown in the drawings has an inclined portion 243 as a whole, such as a pyramid shape or a truncated pyramid shape, a rod rod portion 244 at the bottom of the inclined portion 243, Although the example in which the inclination angle of the portion 243 is changed in the middle and the tip portion 245 is individually illustrated, the glass rod 242 having the truncated pyramid shape and the glass rod 242 having the tip portion 245, and the exit side end There may be a combination such as having a prism portion 244 in the 247 direction, or increasing the inclination angle near the tip even in the shape of a truncated pyramid.

  And this invention is not limited to the form of the above Example, A change and improvement are possible freely in the range which does not deviate from the summary of invention.

100 Projector 110 Top panel
111 Power switch 112 Power lamp indicator
113 Manual image quality adjustment key 114 Automatic image quality adjustment key
115 Light source lamp indicator 116 Heating indicator
118 Loudspeaker 119 Open / close lid
120 Front panel 121 Lens cover
123 Projection port 130 Rear panel
140 Right side panel 145 Exhaust port
150 Left side panel 155 Air intake
160 Bottom panel 170 Forefoot member
175 Rear foot member 180 Circuit board
181 Projector control means 187 Lamp power circuit
190 Cooling fan 210 Light source device
211 Discharge lamp 220 Light source side optical system
221 Color wheel 222 Wheel motor
224 Light guide device 226 Light source side lens group
228 Mirror 230 Display element
240 Light tunnel 241 Reflecting surface
242 Glass rod 243 Slope
244 Square column 245 Tip
246 Entrance 247 Exit side end
250 Projection-side optics 253 Fixed lens group
255 Movable lens group

Claims (12)

A cylindrical light tunnel with a rectangular parallelepiped outer shape and a hollow inside, and a glass rod,
The light tunnel has one end of an opening as an entrance, the other end as an exit end, a reflection surface on the inner surface, and an internal space as a light guide,
The glass rod has an inclined portion that spreads from the entrance side toward the exit side, and an inclined portion is disposed in the light guide path of the light tunnel so that the bottom surface of the light tunnel serves as a light exit. A light guide device.   2. The light guide device according to claim 1, wherein the inclined portion is vertically symmetrical with respect to a horizontal plane including an optical axis and symmetrical with respect to a vertical plane including the optical axis.   The light guide device according to claim 1, wherein the glass rod includes a prism portion at a bottom portion of the inclined portion.   4. The light guide device according to claim 1, wherein the reflection surface in the light tunnel is formed between the entrance and the middle of the inclined portion. 5.   The glass rod has a quadrangular pyramid shape, is arranged so that the central axis is located on the optical axis, the upper surface is located substantially on the same plane as the entrance, and the bottom is the exit side end of the light tunnel. The light guide device according to any one of claims 1 to 4, wherein the light guide device is located on substantially the same plane, and the bottom surface has the same size as the light exit side end of the light tunnel.   6. The light guide device according to claim 1, wherein a vicinity of an incident port side end portion of the inclined portion is a tip portion having a large inclination angle. A light source device;
A light source side optical system;
A display element for generating a projection image;
A projection-side optical system that projects a projection image;
Projector control means,
The light source side optical system includes a color wheel, a light guide device, a light source side lens group, and a reflection mirror,
The light guide device includes:
A cylindrical light tunnel with a rectangular parallelepiped outer shape and a hollow inside, and a glass rod,
The light tunnel has one end of an opening as an entrance, the other end as an exit end, a reflection surface on the inner surface, and an internal space as a light guide,
The projector according to claim 1, wherein the glass rod has an inclined portion that spreads from the entrance side toward the end of the exit side, and an inclined portion is disposed in the light guide path of the light tunnel.   The projector according to claim 7, wherein the inclined portion of the glass rod is vertically symmetric with respect to a horizontal plane including an optical axis and symmetric with respect to a vertical plane including the optical axis.   The projector according to claim 7 or 8, wherein the glass rod includes a prism portion at a bottom portion of the inclined portion.   10. The projector according to claim 7, wherein the reflection surface in the light tunnel is formed between the entrance and the middle of the inclined portion.   The glass rod has a quadrangular pyramid shape, is arranged so that the central axis is located on the optical axis, the upper surface is located substantially on the same plane as the entrance, and the bottom is the exit side end of the light tunnel. The projector according to any one of claims 7 to 10, wherein the projector is located on substantially the same plane, and the bottom surface has the same size as an exit side end of the light tunnel.   The projector according to any one of claims 7 to 11, wherein a vicinity of an incident port side end portion of the inclined portion is a tip portion having a large inclination angle.

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