JP4212500B2 - Projection display device - Google Patents

Description

  The present invention relates to a projection display apparatus such as a liquid crystal projector.

  FIG. 5 is a diagram showing an optical system of a three-plate color liquid crystal projector. The light emitting unit 2 of the light source 1 is composed of an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp or the like, and the irradiation light is emitted as parallel light by the parabolic reflector 3 and guided to the integrator lens 4.

  The integrator lens 4 is composed of a pair of lens groups 4a and 4a, and each pair of lenses guides light emitted from the light source 1 to the entire surface of the liquid crystal light valves 31, 32, and 33. The light that has passed through the integrator lens 4 is unified into, for example, S-polarized light by the polarization conversion device 5 and then guided to the first dichroic mirror 8.

  The first dichroic mirror 8 transmits light in the red wavelength band and reflects light in the cyan (green + blue) wavelength band. The light in the red wavelength band transmitted through the first dichroic mirror 8 is reflected by the total reflection mirror 9 to change the optical path. The red light reflected by the total reflection mirror 9 passes through the condenser lens 10 and passes through the transmissive liquid crystal light valve 31 for red light, and is modulated. On the other hand, the light in the cyan wavelength band reflected by the first dichroic mirror 8 is guided to the second dichroic mirror 11.

  The second dichroic mirror 11 transmits light in the blue wavelength band and reflects light in the green wavelength band. The light in the green wavelength band reflected by the second dichroic mirror 11 passes through the condenser lens 12 and is guided to the transmissive liquid crystal light valve 32 for green light, and is modulated by being transmitted therethrough. The light in the blue wavelength band that has passed through the second dichroic mirror 11 is guided to the transmissive liquid crystal light valve 33 for blue light through the total reflection mirrors 14 and 16, the relay lenses 13 and 15, and the condenser lens 17. The light is modulated by passing through it.

  Each of the liquid crystal light valves 31, 32, 33 includes a panel portion 31b, in which liquid crystal is sealed between an incident-side polarizing plate 31a, 32a, 33a and a pair of glass substrates (with pixel electrodes and alignment films formed). 32b, 33b and output side polarizing plates 31c, 32c, 33c. The modulated light (each color video light) modulated by passing through the liquid crystal light valves 31, 32, 33 is synthesized by the dichroic prism 18 to become color video light. The color image light is enlarged and projected by the projection lens 19 and is projected and displayed on the screen 20.

An opening for intake or exhaust is formed in an apparatus housing (not shown) located on the back side or side of the light source 1. The opening is provided with a louver for preventing leakage light from the light source 1 from coming out of the housing and ensuring ventilation. Further, there is known a projection display apparatus that achieves both improvement in exhaust efficiency and shielding of unnecessary light (see Patent Document 1).
Japanese Patent Laid-Open No. 2003-262921

  However, if a sufficient light-shielding property is obtained by the louver, the clearance becomes narrower and the resistance to the exhaust gas increases, so that the exhaust efficiency decreases.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a projection display apparatus capable of improving exhaust efficiency and blocking unnecessary light.

  In order to solve the above-described problem, a projection display apparatus according to the present invention is a projection display apparatus that modulates and projects light emitted from a light source by an image display panel. A gap between the lower end of the inclined piece portion and the lower end of the louver opening, the louver comprising the inclined piece portion and the louver opening, and a lattice plate disposed outside the louver and having a plurality of lattice openings. The horizontal light leaking from the light is shielded by the horizontal element portion of the lattice plate between adjacent lattice openings, and is parallel light along the inclined piece portion leaking from the gap between the lower surface of the inclined piece portion and the lower end of the louver opening. Is also configured to be shielded from light by the lateral element portion.

  In the above configuration, light leaks from between the lower end of the inclined piece portion of the louver and the lower end of the louver opening, but each lateral element portion of the lattice plate exists on a horizontal line at the position of each gap. Therefore, light shielding by each lateral element portion is performed, and both improvement in exhaust efficiency and light shielding of unnecessary light can be achieved.

  The upper surface of each of the lateral element portions may be an inclined surface with the outer end positioned above the louver side end. According to this, since the light leaked from the louver is reflected on the upper surface of each lateral element portion, the reflected light can be directed to the inside of the device as much as possible, and the light shielding property is further improved.

  As described above, according to the present invention, the louver and the lattice plate located outside the louver are provided, and the relationship between these is devised so that the leakage light from the louver is caused by each lateral element portion of the lattice plate. There is an effect that both the improvement of the exhaust efficiency and the shielding of unnecessary light can be achieved.

  Hereinafter, a projection display apparatus according to an embodiment of the present invention will be described with reference to FIGS. In this embodiment, the liquid crystal projector uses three transmissive liquid crystal display panels, and the image generation optical system is the same as the liquid crystal projector of FIG. 5 used in the description of the conventional example. The description of the image generation optical system is omitted, and the light blocking structure that blocks the leaked light from the light source 1 will be mainly described.

  FIG. 1 is a perspective view showing a light source 1 and a light shielding structure in a liquid crystal projector, and a part of an apparatus housing 50 is cut out so that the light source 1 and a cooling fan 40 can be seen.

  An opening for ventilation (in this embodiment, for exhaust) is formed on the back side of the light source 1. A grid plate 51 is provided outside the opening. A louver 52 is provided inside the opening. A cooling fan 40 is disposed between the louver 52 and the light source 1. The inside air heated by the heat generated from the light source 1 and the like is sucked by the cooling fan 40 and discharged outside the device.

  FIG. 2 is a sectional view showing the positional relationship between the louver 52 and the lattice plate 51 and the structure of each. The louver 52 has a plurality of inclined pieces 52a formed by, for example, pressing a flat iron plate. The louver opening 52b is obtained by forming the inclined piece 52a, but the portion existing at the position of the louver opening 52b is inclined to become the inclined piece 52a, so that the lower end of the inclined piece 52a is formed. And the horizontal line at the lower end of the louver opening 52b do not coincide with each other, and a gap α exists between the horizontal lines.

  Each horizontal element portion 51a of the lattice plate 51 is present on a horizontal line at the position of each gap α, and has a vertical thickness (height) that intersects the horizontal lines.

  Leakage light is generated between the lower end of the inclined piece portion 52a of the louver 52 and the lower end of the louver opening 52b (gap α), but each lateral element portion 51a of the lattice plate 51 is on a horizontal line at the position of each gap α. Since it exists and has a vertical thickness that intersects the two horizontal lines, the leaked light is blocked by each horizontal element portion 51a, so that both exhaust efficiency can be improved and unnecessary light can be blocked.

  In addition, by further increasing the vertical thickness of each horizontal element portion 51a shown in FIG. 2, the louver side upper end and the outer lower end of the lattice opening 51b can be positioned on the extension line of the lower surface of the inclined piece portion 52a. . In the case of such a configuration, although the grating opening 51b is somewhat narrowed, the light shielding property is further improved.

  On the other hand, as shown in FIG. 3, the upper surface of each lateral element portion 51a is inclined with the outer end positioned above the louver side end, thereby extending the lower surface of the inclined piece portion 52a. It is also possible to position the upper end and the outer lower end of the lattice opening 51b on the louver side. Here, the leaked light that leaks from the louver opening 52b and hits the upper surface of each lateral element portion 51a may be reflected by the upper surface and exit to the outside of the lattice plate 51. As described above, by making the upper surface of each horizontal element portion 51a an inclined surface, the reflected light from the upper surface of each horizontal element portion 51a can be directed to the inside of the device as much as possible, and the light shielding property is further improved.

  Further, as shown in FIG. 4, the vertical thickness of each horizontal element portion 51a of the lattice plate 51 (vertical thickness intersecting with both horizontal lines) is secured at the outer end of each horizontal element portion 51a. May be. With the configuration shown in FIG. 4, the angle of the upper surface (inclined surface) of each horizontal element portion 51a can be made steep, and the reflected light from the upper surface of each horizontal element portion 51a can be reliably directed to the inside of the apparatus. Yes.

  In the example described above, an image generation optical system using three transmissive liquid crystal display panels is shown. However, the present invention is not limited to such an image generation optical system, and other image generation optical systems are used. It can also be applied to.

It is the perspective view which showed the light-shielding structure of the liquid crystal projector of embodiment of this invention. It is sectional drawing which showed the positional relationship and each structure of a louver and a lattice board. It is sectional drawing which showed the positional relationship of a louver and a lattice board, and the other example of each structure. It is sectional drawing which showed the positional relationship of a louver and a lattice board, and the other example of each structure. It is explanatory drawing which illustrated the optical system of the liquid crystal projector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 51 Grid plate 51a Lateral element part 51b Grid opening 52 Louver 52a Inclined piece part 52b Louver opening

Claims (2)

In a projection display apparatus that modulates and projects light emitted from a light source by an image display panel, a louver composed of a plurality of inclined pieces and a louver opening formed in the apparatus housing, and on the outside of the louver The horizontal light leaking from the gap between the lower end of the inclined piece portion and the lower end of the louver opening is arranged by a horizontal element portion of the lattice plate between adjacent lattice openings. In addition to being shielded from light, it is configured so that parallel light along the sloped piece leaking from the gap between the lower surface of the sloped piece and the lower end of the louver opening is also shielded by the lateral element part. Projection-type image display device. 2. The projection image display device according to claim 1, wherein an upper surface of each of the lateral element portions is inclined with an outer end positioned above the louver side end. Display device.

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