JP2018036456A - Projection type display apparatus, cooling control method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To include a reflection type liquid crystal display device and extend the life of a lamp.SOLUTION: A liquid crystal projector 1 comprises control means 70 that controls fan control means 98 so that a cooling force generated by a cooling fan 95 when light returning from a reflection type liquid crystal display device 50 to a lamp 10 has a first light intensity becomes higher than a cooling force when the returning light has a second light intensity equal to or less than the first light intensity.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a projection display device (projection image display device) having a reflective liquid crystal display element.

  Projection type display devices such as liquid crystal projectors generally use a lamp such as an ultrahigh pressure mercury lamp as a light source. In order to extend the life of the lamp, it is necessary to control the bulb temperature of the lamp within an appropriate range. Patent Document 1 discloses a projection display device that controls the number of rotations of a cooling fan that cools a lamp in accordance with a signal corresponding to return light from a rear surface of a diaphragm to a lamp and a signal corresponding to an ambient temperature of the lamp. Is disclosed.

Japanese Patent No. 5191741

  An LCoS (Liquid crystal on silicon) (trademark) panel is known as a reflective liquid crystal panel (reflective liquid crystal display element). When a reflective liquid crystal panel is used, part of the light irradiated on the reflective liquid crystal panel is returned to the lamp, increasing the lamp temperature and shortening the lamp life. Patent Document 1 does not consider the return light from such a reflective liquid crystal panel.

  It is an object of the present invention to provide a projection display device, a cooling control method, and a program that have a reflective liquid crystal display element and can improve the life of a lamp.

  A projection display device according to one aspect of the present invention includes a lamp as a light source, a cooling unit that cools the light source, a reflective liquid crystal display element that modulates light from the light source, and the reflective liquid crystal display element. The cooling power of the cooling means when the return light to the light source has a first light quantity is the cooling power of the cooling means when the return light has a second light quantity equal to or less than the first light quantity. Cooling control means for controlling the cooling means so as to be higher than the force.

  An object of the present invention is to provide a projection display device, a cooling control method, and a program that have a reflective liquid crystal display element and can improve the life of a lamp.

It is a flowchart for demonstrating the cooling control method of the lamp | ramp of this invention. It is a block diagram of the projection type display apparatus of this invention. It is a schematic sectional drawing which shows the cooling means of the lamp | ramp shown in FIG. It is a schematic sectional drawing which shows the structure of the liquid crystal display element shown in FIG. It is a figure which shows the light intensity distribution of the return light from the liquid crystal display element shown in FIG. 2 to a lamp | ramp. It is a schematic sectional drawing of the modification of the cooling means shown in FIG. It is a schematic sectional drawing which shows the state of the 1st air duct when the light shielding component shown in FIG. 2 is open. It is a schematic sectional drawing which shows the state of the 1st air guide path when the light shielding component shown in FIG. 2 is closed.

  FIG. 2 is a configuration diagram of the liquid crystal projector 1 as the projection display device according to the embodiment of the present invention. The liquid crystal projector 1 projects (projects) and displays an image on a screen 200 as a projection surface. The liquid crystal projector 1 includes a housing 1a, a lamp 10, an illumination optical system 20, a color separation / synthesis optical system 30, a projection optical system 40, a reflective liquid crystal display element 50, a storage unit 60, and a control unit 70. And an arithmetic means 80.

  The housing 1a is a box-shaped member that fixes and houses members constituting the liquid crystal projector 1. A part of the projection optical system 40 is exposed to the outside from the housing 1a, but it may not be exposed. The housing 1 a has an adjustment mechanism that adjusts the tilt of the liquid crystal projector 1. The installation method of the housing 1a (flooring, ceiling suspension, rear ceiling suspension, etc.) is not limited.

  The lamp 10 is a light source that generates light, and includes, for example, an ultrahigh pressure mercury lamp. FIG. 3 is a schematic sectional view showing a more detailed structure of the lamp 10. The lamp 10 includes a bulb 11, a reflector 12, an electrode 13, a lead wire 14 that supplies power to the electrode, and a connection portion 15 that connects the electrode 13 and the lead wire 14. γ is the optical axis of the liquid crystal projector 1.

  The bulb 11 emits white light with a continuous spectrum and is made of quartz glass. The reflector 12 condenses the light from the bulb 11 in a predetermined direction. The reflector 12 is composed of a mirror having a high reflectance and has a hemispherical shape. The electrode 13 emits electrons from the power supplied via the lead wire 14 by a power supply unit (not shown). Thereby, the lamp 10 emits light.

  When the lamp 10 is lit, the temperature of the entire lamp 10, particularly the bulb 11, rises due to heat generated by electron collision with the electrode 13. If the temperature of the bulb 11 continues to rise, the illuminance lowers due to the crystallization of the glass and the peeling of the connecting portion 15 occurs. Therefore, it is necessary to cool the bulb 11 and the connecting portion 15. Therefore, a cooling means for cooling the lamp 10 is provided.

  The cooling means includes a cooling fan 95 that sends wind, an air guide path 90 that guides the wind from the cooling fan 95 to the lamp 10, and a fan control means 98. The cooling fan 95 may be any name such as a fan or a blower as long as it is a blower (blower unit) that sends air. The fan control means 98 controls the number of revolutions of the cooling fan 95 by controlling the electric power applied to the cooling fan 95.

  The air guide path 90 individually cools the bulb 11 and the connection portion 15 of the lamp 10, and therefore the first air guide passage 91 that guides the wind for cooling the bulb 11 and the air flow for cooling the connection portion 15. And a second air guide path 92 that guides the air. Similarly, the cooling fan 95 includes a first cooling fan 96 connected to the first air guide path 91 and a second cooling fan 97 connected to the second air guide path 92. The fan control means 98 controls the driving of the first cooling fan 96 and the second cooling fan 97 individually and independently. Thereby, the bulb | ball 11 and the connection part 15 can each be maintained in a suitable temperature range, and the lifetime of the lamp | ramp 10 can be extended.

  The illumination optical system 20 transmits light that illuminates a reflective liquid crystal display element (hereinafter simply referred to as “liquid crystal display element”) 50 to the color separation / synthesis high school system 30. The illumination optical system 20 includes cylinder arrays 21 and 22, an ultraviolet absorption filter 23, a polarization conversion element 24, a front compressor 25, a total reflection mirror 26, a condenser lens 27, a rear compressor 28, and a light blocking component 29. And having.

  The cylinder arrays 21 and 22 are composites of photosensitive elements incorporated in a camera, a detector, a scanning device, and the like. The cylinder array 21 is a lens array having a refractive power in a direction perpendicular to the optical axis γ. The cylinder array 22 has a lens array corresponding to each lens of the cylinder array 21. In the present embodiment, the cylinder array 21 is disposed in front of the lamp 10 in the direction in which the light from the lamp 10 travels, and the cylinder array 22 is disposed in front of the ultraviolet absorption filter 23 described later.

  The ultraviolet absorption filter 23 absorbs ultraviolet rays. The ultraviolet absorption filter 23 is disposed between the cylinder array 21 and the cylinder array 22. The polarization conversion element 24 converts non-polarized light into predetermined polarized light. The polarization conversion element 24 is disposed in front of the cylinder array 22. The front compressor 25 is composed of a cylindrical lens having a refractive power in the horizontal direction. The front compressor 25 is disposed in front of the polarization conversion element 24.

  The total reflection mirror 26 has a function of reflecting light from the lamp 10. In the present embodiment, the total reflection mirror 26 bends the optical axis by 90 degrees. The total reflection mirror 26 is disposed in front of the front compressor 25. The condenser lens 27 collects light from the lamp 10 and illuminates the object uniformly by forming an image of the light source on the pupil of the projection optical system 40. The condenser lens 27 is disposed in front of the total reflection mirror 26.

  The rear compressor 28 is composed of a cylindrical lens having a refractive power in the horizontal direction. The rear compressor 28 is disposed in front of the condenser lens 27.

  The light blocking component 29 is configured by a reflection mirror on the incident side of the lamp 10. In this embodiment, the light blocking component 29 is configured to be movable so as to block light from the lamp 10 and allow light from the lamp 10 to pass. . The light blocking component 29 includes an aperture that blocks the light from the lamp 10 in stages and a shutter that blocks all the light from the lamp 10. The driving of the light blocking component 29 is controlled by the light blocking control means 75 according to the operation of the input means (not shown) by the user. For example, in a presentation that the reporter stands near the screen 200 and explains, light from the lamp 10 can be blocked by the light blocking component 29 so that the projected light does not enter the reporter's eyes.

  When the light blocking component 29 is closed, the light from the lamp 10 is reflected by the light blocking component 29 and returns to the lamp 10. This return light raises the temperature of the bulb 11. Therefore, when the light blocking control means 75 determines that the light blocking component 29 is closed, the information is transmitted to the control means 70, and the control means 70 determines the rotational speed of the first cooling fan 96 via the fan control means 98. Set high. Or you may lower the temperature of the wind of the 1st air guide path 91 so that it may mention later. When the light blocking control means 75 determines that the light blocking component 29 is opened, the information is transmitted to the control means 70, and the control means 70 determines the rotation speed of the first cooling fan 96 via the fan control means 98. Set low. Or you may raise the temperature of the wind of the 1st air guide path 91 so that it may mention later. As a result, the temperature of the bulb 11 can be kept constant regardless of the return light.

  The light shielding component 29 may completely block the light from the lamp 10 or may partially block the light. In the latter case, the light blocking control means 75 determines the aperture amount, the information is transmitted to the control means 70, and the valve 11 is changed by changing the rotational speed of the first cooling fan 96 via the fan control means 98. The temperature can be kept constant regardless of the return light. In this case, the control means 70 stores the relationship between the throttle amount and the rotation speed of the first cooling fan 96 in order to keep the temperature of the valve 11 constant in the storage means 60 and obtains it from the light blocking control means 75. Based on the obtained information, the rotational speed of the first cooling fan 96 is determined. Thereafter, the control means 70 controls the driving of the cooling fan 96 based on the determined rotational speed via the fan control means 98.

  The color separation / synthesis optical system 30 decomposes and synthesizes light from the lamp 10, and a dichroic mirror 31, a polarizing plate 32, a polarizing beam splitter 33, a quarter wavelength plate 35, and a color selective phase difference plate 36. And having.

  The dichroic mirror 31 reflects light in the blue (B) and red (R) wavelength regions and transmits light in the green (G) wavelength region. The dichroic mirror 31 is disposed in front of the rear compressor 28.

  The polarizing plate 32 shields P-polarized light and transmits S-polarized light, and includes polarizing plates 32a, 32b, and 32c. The polarizing plate 32a is a green incident-side polarizing plate in which a polarizing element is bonded to a transparent substrate, and is disposed between the dichroic mirror 31 and the polarizing beam splitter 33a. The polarizing plate 32b is a red-blue incident-side polarizing plate in which a polarizing element is bonded to a transparent substrate, and is disposed between the dichroic mirror 31 and the color selective phase difference plate 36a. The polarizing plate 32c is an emission-side polarizing plate (polarizing element) for red and blue in which a polarizing element is bonded to a transparent substrate, and is provided between the color selective phase difference plate 36b and the polarizing beam splitter 33c.

  The polarization beam splitter 33 has a polarization separation surface that transmits P-polarized light and reflects S-polarized light. The polarization beam splitter 33 includes polarization beam splitters 33a, 33b, and 33c. The polarizing beam splitter 33a is disposed at the subsequent stage of the polarizing plate 32a. The polarization beam splitter 33b is disposed at the subsequent stage of the color selective phase difference plate 36a. The polarizing beam splitter 33c is disposed at the subsequent stage of the polarizing beam splitters 33a and 33b.

  The quarter-wave plate 35 gives a phase difference of π / 2 (= λ / 4) to the electrolytic vibration direction (polarization plane) of incident light. The quarter wavelength plate 35 includes quarter wavelength plates 35R, 35G, and 35B. The quarter wavelength plate 35R is disposed between the polarization beam splitter 33b and the liquid crystal display element 50R. The quarter wavelength plate 35G is disposed between the polarization beam splitter 33a and the liquid crystal display element 50G. The quarter wavelength plate 35B is disposed between the polarization beam splitter 33b and the liquid crystal display element 50B.

  The color selective phase difference plate 36 converts the polarization direction of specific light by 90 degrees and includes color selective phase difference plates 36a and 36b. The color selective phase difference plate 36a converts the polarization direction of blue light by 90 degrees and does not convert the polarization direction of red light. The color selective phase difference plate 36a is disposed between the polarizing plate 32b and the polarizing beam splitter 33b. The color selective phase difference plate 36b converts the polarization direction of the red light by 90 degrees and does not convert the polarization direction of the blue light. The color selective phase difference plate 36b is disposed between the polarizing plate 32c and the polarizing beam splitter 33b.

  The projection optical system (projection means) 40 projects the reflected light from the liquid crystal display element 50 onto the screen 200, the lens barrel 40 a, a plurality of optical elements (not shown) housed therein, and an image projected onto the screen 200. And a shift mechanism 41 for shifting.

  FIG. 4 is a schematic cross-sectional view showing the structure of a liquid crystal display element (image forming element) 50 that represents the liquid crystal display elements 50R, 50G, and 50B shown in FIG. The liquid crystal display element 50 is a light modulation element that modulates light from the lamp 10 based on an input image signal, and is a reflective liquid crystal display element configured as an LCoS (trademark) panel.

The liquid crystal display element 50 is manufactured by enclosing a liquid crystal layer 55 between the first substrate 51 and the second substrate 56. The first substrate 51 includes a glass substrate 52, a transparent electrode 53, and an alignment film 54. A transparent electrode 54 is disposed on the glass substrate 52. The second substrate 56 includes an alignment film 57, a reflective electrode 58, and a Si substrate 59. On the Si substrate 59, a semiconductor circuit for driving the liquid crystal display element 50 is configured, and a reflective electrode 58 is disposed on the surface. On the first substrate 51 and the second substrate 56, alignment films 54 and 57 for arranging liquid crystal molecules are arranged on the surface side in contact with the liquid crystal layer 55, respectively. The transparent electrode 54 is an ITO electrode, and the reflective electrode 55 is an electrode mainly composed of Al or the like. The alignment film 56 is a film for aligning liquid crystal molecules in the vertical direction, and is formed by obliquely depositing an inorganic alignment film SiO ₂ or rubbing a polyimide film or the like.

  A liquid crystal material having negative dielectric anisotropy can be used for the liquid crystal material of the liquid crystal layer 51. Let Δn be the refractive index anisotropy of the liquid crystal material. The refractive index anisotropy is given by the difference between the refractive index ne of the liquid crystal molecules in the major axis direction and the refractive index no in the uniaxial direction. This refractive index value has chromatic dispersion characteristics, and has a unique value for each wavelength. By applying a voltage between the transparent electrode 54 and the reflective electrode 55, the direction of the liquid crystal material existing in the liquid crystal layer 51 is changed, the refractive index anisotropy Δn is changed, and the position relative to the polarized incident light is changed. Add phase difference. Light having a phase difference and a polarization axis different from the incident polarization axis is selectively transmitted or reflected by the polarization beam splitter 33 to be guided and projected to the projection optical system 40. The light having the same polarization axis as the incident polarization axis without a phase difference is returned to the lamp 10 by being selectively reflected or transmitted by the polarization beam splitter 33 with the reverse characteristics to the above.

  An image signal received from an external device connected to the liquid crystal projector 1 is stored in the storage unit 60. The computing unit 80 generates a signal to be applied to the liquid crystal display element 50 based on the image signal stored in the storage unit 60. The control unit 70 transmits the signal generated by the calculation unit 80 to the liquid crystal display element 50. The memory | storage means 60, the control means 70, and the calculating means 80 function as a cooling control means (cooling control apparatus).

  FIG. 5 is a diagram showing the distribution of return light from the liquid crystal display element 50 to the lamp 10. From FIG. 5, it can be seen that the light returns intensively to the bulb 11. As a result, the temperature rise of the bulb 11 increases and the crystallization of the glass proceeds. The connection portion 15 has little return light, and the temperature of the connection portion 15 hardly increases. Accordingly, the temperature of the bulb 11 can be optimized and the life of the lamp 10 can be improved without causing an excessive cooling load by causing the cooling condition of the bulb 11 to follow the light quantity (light intensity) of the return light.

  FIG. 1 is a flowchart for explaining a cooling control method for the lamp 10. “S” represents a step (process), “Y” represents Yes, and “N” represents No. The flowchart shown in FIG. 1 is executed by cooling control means configured as a microcomputer. The cooling control method is stored as a computer program in the storage unit 60 or other storage unit provided in the liquid crystal projector 1. Further, some or all of the functions of the cooling control means may be combined with other control means such as the fan control means 98. The computer program may be stored in a non-transitory computer readable storage medium.

  First, the control unit 70 analyzes an image signal received from the outside via the calculation unit 80 (S10), and creates a histogram representing the luminance distribution of the image of each frame (S12). The control means 70 determines whether or not a dark image has been acquired based on the histogram created by the calculation means 80 (S14). When a bright image is received, the proportion of the light projected from the lamp 10 is large, so that the return light from the liquid crystal display element 50 to the lamp 10 is reduced. When a dark image is received, the proportion of the light projected from the lamp 10 decreases, so that the return light from the liquid crystal display element 50 to the lamp 10 increases.

  For example, in a histogram of an image of one frame, consider a case where the horizontal axis is the luminance value and the vertical axis is the number of pixels (frequency). The control means 70 acquires information representative of the brightness of the image signal (hereinafter simply referred to as “brightness value”) obtained from the histogram by means of a simple average or a weighted average of the brightness values. In S14, the control means 70 compares the luminance value with a predetermined threshold value. When a bright image is acquired (when the luminance value is higher than the threshold value) (N in S14), the control unit 70 causes the fan control unit 98 to control the rotation speed of the first cooling fan 96 to be low ( S16). On the other hand, when a dark image is acquired (when the luminance value is equal to or less than the threshold value) (Y in S14), the control unit 70 causes the fan control unit 98 to control the rotation speed of the first cooling fan 96 to be high. (S18).

  In the present embodiment, the control means 70 has a second cooling power by the first cooling fan 96 when the return light from the liquid crystal display element 50 to the lamp 10 has the first light quantity. The fan control means 98 is controlled so as to be higher than the cooling power when the amount of light is present. The control unit 70 also cools a portion of the lamp where the return light is concentrated (that is, the bulb 11) based on information indicating the amount of return light from the liquid crystal display element 50 to the lamp 10. Controls the cooling power.

  The number of rotations of the first cooling fan 96 is not limited to two types, that is, a high-speed rotation number and a low-speed rotation number, but a plurality of three or more preset rotation numbers, or a continuously changing rotation number. It may be configured as. For example, the control means 70 stores the relationship between the brightness value and the applied power value corresponding to the rotation speed of the first cooling fan 96 in order to keep the temperature of the valve 11 constant in the storage means 60 in advance. The fan control means 98 may be controlled based on the relationship information and the luminance value information. As a result, the temperature of the bulb 11 can be kept constant regardless of the return light.

  In this embodiment, the control means 70 determines the magnitude of the amount of return light based on the histogram of the image signal created in S12. However, the control means 70 obtains a histogram of each color, performs weighting by the color component, and returns. You may judge the magnitude of the light quantity. The influence on the temperature rise of the lamp 10 is different for each color component. The influence on the temperature rise of the lamp 10 is the highest in green, followed by blue and red. Therefore, the control means 70 maximizes the green weight, then increases the blue weight, and minimizes the red weight in the image signal. By performing the weighting by the color component, it is possible to reflect the influence of each color corresponding to the temperature rise of the lamp 10 and to detect the temperature rise of the lamp 10 with high accuracy.

  Further, the luminance value of the image signal obtained in S12 may be weighted by the projection time, and the magnitude of the return light amount may be determined. Since the still image is projected for a long time, the influence of the return light is large, and since the moving image is a short-time projection, the influence of the return light is small. The projection time is measured from a clock provided in the cooling control means and a counter that counts the number of clocks. The control means 70 increases the weight as the projection time is longer, and decreases the weight as the projection time is shorter. Thereby, the detection accuracy of the quantity of return light can be improved. In this case, weighting for each color component may be further performed.

  Further, the magnitude of the amount of return light may be determined by further performing weighting according to the lighting time of the lamp 10. If the lighting time of the lamp 10 is short, its temperature is not high, so there are cases where it is not necessary to increase the cooling power of the cooling means even if the amount of return light is large. The lighting time of the lamp 10 may be measured from a clock provided in the cooling control means and a counter that counts the number of clocks. The control means 70 increases the weight as the lighting time of the lamp 10 is longer, and decreases the weight as the lamp 10 is shorter. Thereby, cooling corresponding to the temperature of the lamp 10 can be performed. Of course, one or both of the weighting for each color component and the weighting by the projection time may be combined.

  In addition, the control unit 70 may determine from an image signal of a plurality of frames instead of determining from an image signal of one frame. Further, an optical sensor (light quantity detection means) for detecting the light quantity of return light or projection light (not shown) may be provided, and the control means 70 may determine the light quantity of the return light based on the detection result of the optical sensor.

  Further, the control means 70 determines whether the received image signal represents a moving image or a still image, and if it is determined that the received image signal represents a moving image, the first control is performed so that a change in fan noise is not recognized by the viewer. You may control so that the rotation speed (namely, air volume) of the cooling fan 96 may not be changed.

  The control means 70 adjusts the amount of change in the rotational speed of the first cooling fan 96 to be within a predetermined range (that is, limits the amount of change), and suddenly increases noise due to the change in the rotational speed of the first cooling fan 96. You may prevent a change. Further, the control means 70 does not need to work when projecting a moving image, and does not work when projecting a still image.

  Further, instead of providing the two cooling fans of the first cooling fan 96 and the second cooling fan 97, one common fan is provided, and the partition walls of the first air guiding path 91 and the second air guiding path 92 are provided. May be configured to be movable. In this case, the control means 70 controls the drive means for moving the partition wall based on the amount of return light, and adjusts the ratio of the first air guide path 91 to the second air guide path 92 to thereby adjust the valve 11. The cooling performance may be adjusted.

  The cooling method is not limited to the method shown in FIG. FIG. 6 is a schematic cross-sectional view showing a method for controlling the cooling temperature of the valve 11 without changing the amount of air blown onto the valve 11. When the rotation speed of the cooling fan 95 and the size of the first air guide path 90 are changed, the noise and sound quality of the liquid crystal projector 1 are changed. Therefore, as shown in FIG. 6, a Peltier element 99 is attached to a part of the first air guide path 91, and the control means 70 changes the power applied to the Peltier element 99 according to the amount of return light, You may change the temperature of the wind sprayed on the valve | bulb 11. FIG.

  That is, when a bright image is acquired, the control means 70 maintains the rotational speed of the cooling fan 95 by the fan control means 98, and the Peltier element driving means (not shown) so that the power applied to the Peltier element 99 is reduced. To control. On the other hand, when acquiring a dark image, the control means 70 maintains the rotational speed of the cooling fan 95 by the fan control means 98 and maintains the rotational speed of the cooling fan 95 so that the electric power applied to the Peltier element 99 is increased. To control. In other words, the control means 70 detects the wind when the temperature of the wind sent from the first cooling fan 96 to the lamp 10 when the return light has the first light amount has the second light amount equal to or less than the first light amount. The electric power applied to the Peltier element 99 is controlled so as to be lower than the temperature of.

  Note that the power applied to the Peltier element 99 is not limited to two types of high power and low power, but may be configured to change three or more types of preset power or continuously. For example, the control unit 70 may store the relationship between the luminance value and the applied power to the Peltier element in the storage unit 60 in order to keep the temperature of the bulb 11 constant. In this case, the control means 70 may control the Peltier element driving means based on the relationship information and the acquired luminance value information. As a result, the temperature of the bulb 11 can be kept constant regardless of the return light.

  In the present embodiment, the Peltier element 99 is disposed directly on the first air guide path 91, but a metal component that is in thermal contact with the Peltier element may be disposed on the first air guide path 91. . Further, by combining the cooling method shown in FIG. 3 and the cooling method shown in FIG. 6, both the air volume and the temperature may be changed based on the magnitude of the amount of return light. The Peltier element is an example of a thermoelectric element, and a thermoelectric element that uses a thermoelectric effect (Seebeck effect or the like) other than the Peltier effect may be used.

  In this embodiment, the light blocking control means 75 determines the opening / closing of the light blocking component 29 and controls the number of revolutions of the valve cooling fan 96. However, as shown in FIGS. The temperature of the valve 11 may be controlled without changing the rotational speed of the fan 96. FIG. 7 is a schematic cross-sectional view showing a state of the first air guide path 91 when the light blocking component 29 is open, and FIG. 8 is a diagram showing the first wind guide when the light blocking component 29 is closed. 3 is a schematic cross-sectional view showing a state of a path 91. FIG. A wind guide plate 93 is attached to the end of the light shielding component 29.

  In the state shown in FIG. 7, the light blocking component 29 is open, an opening 91 a is formed in the first air guide path 91, and the inside of the first air guide path 91 is formed through the opening 91 a. The air guide plate 93 and a part of the light shielding component 29 protrude. As a result, the first air guide path 91 is restricted by the air guide plate 93, and the wind restricted by the air guide plate 93 is used for cooling other optical components (for example, the illumination optical system 20). The air guide plate 93 is parallel to the first air guide path 91, but the angle is not limited. Further, the shape of the opening 91a is not limited.

  In the state shown in FIG. 8, the light blocking component 29 is closed. The opening 91 a is closed by a plate member 91 b attached to the end of the air guide plate 93. The first air guide path 91 is not restricted by the air guide plate 93, and there is no restriction on the wind for cooling the valve 11, and the amount of cooling air to the valve 11 is increased.

  By adopting this configuration, it is possible to determine the open / closed state of the light blocking component 29 and change the cooling state of the bulb 11 without changing the rotational speed of the cooling fan 95 and, as a result, the noise state of the liquid crystal projector 1. It becomes possible. Further, when part or all of the restricted wind when the light blocking component 29 is open is used for cooling the illumination optical system 20, it is possible to suppress the noise of the liquid crystal projector 1. When the light blocking component 29 is open, a part of the light from the lamp 10 is absorbed by the illumination optical system 20 to generate heat, and thus needs to be cooled. However, when the light blocking component 29 is closed, the light from the lamp 10 is blocked and the illumination optical system 20 does not generate heat and does not need to be cooled.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal projector (projection type display apparatus), 10 ... Lamp, 50 ... Reflection type liquid crystal display element, 70 ... Control means (cooling control means), 90 ... Air guide path, 95 ... Cooling fan, 98 ... Fan control means

Claims (11)

A lamp as a light source;
Cooling means for cooling the light source;
A reflective liquid crystal display element for modulating light from the light source;
When the return light from the reflective liquid crystal display element to the light source has a first light amount, the cooling power of the cooling unit with respect to the light source is such that the return light has a second light amount equal to or less than the first light amount. Cooling control means for controlling the cooling means to be higher than the cooling power of the cooling means at the time,
A projection type display device comprising: The reflective liquid crystal display element modulates light from the light source based on information corresponding to an image signal,
The projection display apparatus according to claim 1, wherein the cooling control unit determines the amount of the return light based on information on luminance of the image signal.   The cooling control means has at least one of weighting for each color component of the image signal, weighting by the projection time of the image signal, and weighting by the lighting time of the lamp for the luminance information of the image signal. The projection type display device according to claim 2, wherein the projection type display device determines the amount of the return light based on the information of the result. A light amount detecting means for detecting the light amount of the projection light or the return light projected by the projection display device;
The projection display device according to claim 1, wherein the cooling control unit determines a light amount of the return light based on a detection result of the light amount detection unit. The cooling means includes a blowing means and a thermoelectric element that cools the wind sent from the blowing means to the light source,
The cooling control unit is configured to perform the blowing when the temperature of the wind sent from the blowing unit to the light source when the return light has the first light amount has a second light amount equal to or less than the first light amount. 4. The projection display device according to claim 1, wherein the power applied to the thermoelectric element is controlled so as to be lower than a temperature of wind sent from the means to the light source. 5.   The cooling control means controls the cooling power of the cooling means for cooling the portion of the light source where the return light concentrates based on information representing the light quantity of the return light. The projection type display device according to any one of the above.   The projection display device according to claim 1, wherein the cooling control unit limits a change amount of the cooling power of the cooling unit to a predetermined range. The reflective liquid crystal display element modulates light from the light source based on information corresponding to an image signal,
The cooling means has air blowing means,
The cooling control means changes the air volume of the air blowing means when the image signal is a still image, and does not change the air volume of the air blowing means when the image signal is a moving image. 4. The projection type display device according to any one of 1 to 3. An illumination optical system that illuminates the reflective liquid crystal display element with light from the light source;
A light blocking component configured to be movable so as to block light from the light source and allow the light to pass through;
Further comprising
The cooling means includes a blowing means and a wind guide path for guiding the wind sent from the blowing means to the light source,
When the light blocking component allows light from the light source to pass, a part of the light blocking component protrudes into the air guide path and restricts the wind from the blower to the illumination optical system. Part of the
The projection according to any one of claims 1 to 8, wherein when the light blocking component blocks light from the light source, the light blocking component does not limit the air guide path. Type display device. A cooling control method for controlling the cooling power of a cooling means for cooling a lamp as a light source in a projection display device,
When the return light from the reflective liquid crystal display element that modulates the light from the light source to the light source has a first light amount, the cooling power of the cooling means with respect to the light source is less than the first light amount. A cooling control method comprising the step of controlling the cooling means so as to be higher than the cooling power of the cooling means when having the second light quantity. A program for causing a computer to execute a cooling control method for controlling the cooling power of a cooling means for cooling a lamp as a light source in a projection display device,
In the cooling control method, when the return light from the reflective liquid crystal display element that modulates the light from the light source has a first light amount, the cooling power of the cooling means with respect to the light source is such that the return light is A program comprising the step of controlling the cooling means so as to be higher than the cooling power of the cooling means when the second light quantity is equal to or less than the first light quantity.