JP6683085B2 - LCD projector - Google Patents

Description

  The present invention relates to a liquid crystal projector device using a liquid crystal display element.

  In general, a liquid crystal projector device that displays a color image has three liquid crystal display elements (hereinafter, simply referred to as “display element”) provided for each of red (R), green (G), and blue (B) which are primary color light components. The light emitted from the light source is reflected or transmitted, and a lens is used to project an image on the screen.

  While the liquid crystal projector device is in use, the temperature of each display element rises due to the heat generated by the driving circuit and the heat generated by the light emitted from the light source, but the display element changes its light reflection or transmission characteristics depending on the temperature. Temperature control of the display element is required to maintain high quality images. In the temperature control of the display elements, it is important to control the temperature of each display element within a predetermined temperature range and at the same time maintain the temperature balance between the display elements. In order to control the temperature of the display element with higher accuracy, a liquid crystal projector device is disclosed in which a temperature sensor and a cooling fan are installed in each display element to control the temperature of the display element.

Patent No. 5388394

  Immediately after turning on the power of the liquid crystal display device, or when the ambient temperature is extremely high or extremely low, it may not be possible to control all the display elements within the target temperature range. For example, when only one of the three display elements is out of the target temperature range, the temperature balance between the elements is not maintained and the color balance is lost, so that the quality of the projected image cannot be maintained. there is a possibility.

  The present invention provides a liquid crystal projector device that controls the temperature of each display element so that a suitable temperature balance is maintained between the display elements even in an environment in which all the display elements cannot be controlled within a predetermined temperature range. The purpose is to do.

  A liquid crystal projector device of the present invention to achieve the above object, a plurality of display elements (161, 221, 251) for modulating light of different color components, respectively, a plurality of temperature detection unit for detecting the temperature of each of the plurality of display elements. (165,225,255), a plurality of cooling units (163,223,253) for cooling each of the plurality of display elements, and a temperature of each of the plurality of display elements according to the detection results of the plurality of temperature detection units by the plurality of cooling units. A control unit (27) for controlling by cooling, wherein the control unit displays another display when the temperature of the display element having the slowest temperature increase rate among the plurality of display elements is lower than a predetermined temperature. The temperature of the element is controlled to be within a predetermined range based on the temperature of the display element having the slowest temperature increase rate.

  Further, in a liquid crystal projector device according to another aspect of the present invention, the cooling unit is a blower fan, and the control unit controls the rotation speed of the blower fan based on a detection result of the temperature detection unit. To do.

  According to the liquid crystal projector device of the present invention, the temperature of each display element is controlled so that a suitable temperature balance is maintained between the display elements even in an environment where all the display elements cannot be controlled within a predetermined temperature range. can do.

FIG. 1 is an overall view showing a configuration of a liquid crystal projector device according to an embodiment of the present invention. FIG. 3 is a schematic diagram showing a configuration of each modulation unit and a fan control device in the liquid crystal projector device according to the embodiment of the present invention. 6 is a graph showing a temperature change of each display element immediately after the power of the liquid crystal projector device according to the embodiment of the present invention is turned on. 3 is a graph showing a temperature change of each display element during operation of the liquid crystal projector device according to the embodiment of the present invention.

  Hereinafter, each embodiment of the liquid crystal projector device of the present invention will be described with reference to the accompanying drawings. In each of the embodiments, three display elements (Rch display element, Bch display element, Gch display element) provided for each of red (R), green (G), and blue (B), which are primary color light components, are provided. As an example, a reflective liquid crystal projector device that reflects light emitted from a light source and projects an image on a screen using a lens will be described.

<Configuration of liquid crystal projector device>
The configuration of the liquid crystal projector device used in each embodiment of the present invention will be described with reference to FIG. The liquid crystal projector device 1 includes a light source 11 that emits white light such as a high pressure mercury lamp or a metal halide lamp. The light emitted from the light source 11 is incident on the cross dichroic mirror 12.

  The cross dichroic mirror 12 separates the three primary colors of the incident illumination light into an R (red) component, a G (green) component and a B (blue) component. The R component light that has passed through the cross dichroic mirror 12 passes through a mirror 13 and a relay lens 14, passes through a polarization beam splitter 15 that serves as a polarization separation element, and is incident on an Rch modulator 16. The Rch modulator 16 polarization-modulates the incident R component light according to the red component of the display image and reflects it. The polarization-modulated reflected light is reflected by the polarization beam splitter 15, and enters the color combining prism 17 from one side surface portion.

  On the other hand, the G component light and the B component light that have passed through the cross dichroic mirror 12 enter the dichroic mirror 19 through the mirror 18. The dichroic mirror 19 separates the incident G component light and B component light into G component light and B component light. The G component light reflected by the dichroic mirror 19 passes through a relay lens 20, a polarization beam splitter 21 serving as a polarization separation element, and enters a Gch modulator 22. The Gch modulator 22 polarization-modulates the incident G component light according to the green component of the display image and reflects it. The polarization-modulated reflected light is reflected by the polarization beam splitter 21, and enters the color combining prism 17 from the rear surface portion.

  The B component light that has passed through the dichroic mirror 19 passes through the relay lens 23, the polarization beam splitter 24 that serves as a polarization separation element, and enters the Bch modulator 25. The Bch modulator 25 polarization-modulates the incident B component light according to the blue component of the display image and reflects it. The polarization-modulated reflected light is reflected by the polarization beam splitter 24 and enters the color combining prism 17 from the other side surface portion.

  The color synthesizing prism 17 synthesizes the R component light incident from one side surface portion, the G component light incident from the rear surface portion, and the B component light incident from the other side surface portion, and emits it from the front surface portion. The illumination light emitted from the color synthesizing prism 17 enters a projection lens 26 that serves as a projection optical system. The projection lens 26 projects the incident illumination light toward a screen (not shown), forms an image, and displays an image.

  Detailed configurations of the Rch modulator 16, the Gch modulator 22, and the Bch modulator 25 will be described with reference to the schematic diagram of FIG. The Rch modulator 16 is provided for cooling the Rch display element 161, which modulates the R signal component, the Rch heat sink 162, which radiates the heat of the Rch display element 161, and the Rch display element 161, and the Rch heat sink 162. The Rch fan 163, the Rch duct 164 for sending the wind generated by the operation of the Rch fan 163 to the Rch display element 161 and the Rch heat sink 162, and the Rch temperature for detecting the temperature of the Rch display element 161. And a sensor 165. The Rch fan 163 functions as a cooling unit for the Rch display element 161.

  The Gch modulation unit 22 is provided for cooling the Gch display element 221, which modulates the G signal component, the Gch heat sink 222, which radiates the heat of the Gch display element 221, and the Gch display element 221 and the Gch heat sink 222. The Gch fan 223, the Gch duct 224 for sending the wind generated by the operation of the Gch fan 223 to the Gch display element 221 and the Gch heat sink 222, and the Gch temperature for detecting the temperature of the Gch display element 221. And a sensor 225. The Gch fan 223 functions as a cooling unit for the Gch display element 221.

  The Bch modulator 25 is provided for cooling the Bch display element 251, which modulates the B signal component, the Bch heat sink 252, which radiates the heat of the Bch display element 251, and the Bch display element 251, and the Bch heat sink 252. The Bch fan 253, the Bch duct 254 for sending the wind generated by the operation of the Bch fan 253 to the Bch display element 251 and the Bch heat sink 252, and the Bch temperature for detecting the temperature of the Bch display element 251. And a sensor 255. The Bch fan 253 functions as a cooling unit for the Bch display element 251.

  The Rch fan 163, the Gch fan 223, and the Bch fan 253 are configured by a sirocco fan, an axial fan, or the like. Further, the Rch temperature sensor 165, the Gch temperature sensor 225, and the Bch temperature sensor 255 are configured by a thermistor, for example.

  Further, in the liquid crystal projector device 1, a control unit 27 that controls the rotation speeds of the Rch fan 163, the Gch fan 223, and the Bch fan 253 is installed. The control unit 27 controls the number of rotations of each fan 163, 223, 253 based on the temperature detected by each temperature sensor 165, 225, 255 so that each display element 161, 221, 251 has a desired temperature. Control.

<First Embodiment>
The temperature control operation of each display element 161, 221, 251 in the liquid crystal projector device 1 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 3 is a graph showing the temperature change of each display element immediately after the liquid crystal projector device 1 is powered on.

  When the temperature of each display element is lower than the first set temperature when the liquid crystal projector device 1 is powered on, the control unit 27 controls to raise the temperature of the display element, and thus stops the fan. The “first set temperature” is, for example, “60 ° C.”. The temperature of each display element rises due to heat generated by the drive circuit of the display element itself and heat generated by the light incident from the light source 11. At this time, the temperature rising rate may be different between the display elements. This is because the magnitude of the energy of the light with which the display element is irradiated differs depending on each color component light. Although the magnitude of the energy of each color component light differs depending on the characteristics of the light source 11, the energy of the G component light is generally the largest. Therefore, the temperature rising speed of the Gch display element 221 becomes faster than that of the Rch display element 161 and the Bch display element 251.

For example, as shown in FIG. 3, the temperature of the Gch display element 221 rises as indicated by a thin dashed line G ₀ , while the temperature of the Bch display element 251 is indicated by a thin dashed line B ₀ . The temperature rises at a slow speed, and the temperature of the Rch display element 161 rises at a slower speed as indicated by the solid line R. Therefore, the temperature difference between the Rch display element 161, the Gch display element 221, and the Bch display element 251 becomes large, and an appropriate temperature balance cannot be maintained between the display elements, resulting in a color balance collapse and a projected image The quality is likely to deteriorate.

  Therefore, of the three display elements, when the temperature of the Rch display element 251 having the slowest temperature rising speed is lower than the first set temperature, the control unit 27 controls the temperature of the Gch display element 221 and the Bch display element. The drive of the Gch fan 223 and the Bch fan 253 is controlled so that the temperature of 251 falls within a predetermined range based on the temperature of the Rch display element 161. The predetermined range is, for example, within ± 5 ° C., the temperature of the display device for Gch 221 is within ± 5 ° C., and the temperature of the display device for Bch 251 is ± 5 ° C. Control so that each is within the range.

By controlling in this way, as shown in FIG. 3, the temperature of the display element 221 for Gch becomes like the one-dot chain line G ₁ of the thick line, and the Rch is larger than that when the Gch fan 223 is not driven (G ₀ ). Comes close to the solid line R indicating the temperature rise of the display element 161. Further, the temperature of the Bch display element 251 becomes like a thick two-dot chain line B ₁ , and the solid line R indicating the temperature increase of the Rch display element 161 is higher than when the Bch fan 253 is not driven (B ₀ ). Approach. Therefore, even when the temperature of each display element tends to fluctuate immediately after the power is turned on, the temperature difference between the display elements is reduced, and the quality of the projected image can be improved by maintaining the temperature balance between the display elements at an early stage. .

  After that, when the temperature of the Rch display element 161 becomes higher than the first set temperature, the control unit 27 controls the temperature of each display element to fall within a predetermined temperature range. The predetermined temperature range is, for example, in the range of 60 ° C to 70 ° C.

  Although the present embodiment has been described on the premise that the temperature increase rate of the Rch display element 161 after power-on is slower than that of the Gch display element 221 and the Bch display element 251, the temperature increase rate is not limited to this. The temperature of the other display element may be controlled with reference to the temperature of the display element of the slowest channel. For example, when the temperature rising rate of the Gch display element 221 is the slowest, the temperature of the Gch display element 221 is controlled until the temperature of the Gch display element 221 reaches the first set temperature. To do. Similarly, when the temperature increase rate of the Bch display element 251 is the slowest, the temperature of the other Bch display element 251 is set as the reference until the temperature of the Bch display element 251 reaches the first set temperature. Control. The difference between the temperature rise rates of the display elements after the power is turned on may be compared in advance by experiments.

<Second Embodiment>
The temperature of the display element is controlled by being cooled by the air blown by the fan, but if the environmental temperature is extremely high or, on the contrary, extremely low, it may not be possible to control within the target temperature range depending on the display element. is there.

  FIG. 4 is a diagram showing a temperature change of each display element when the environmental temperature is changed in a state where each display element is controlled so as to be in the target temperature range of 60 to 70 ° C.

  X, Y, and Z represent display elements of different colors, and correspond to any of the Rch display element 161, the Gch display element 221, and the Bch display element 251, respectively. The temperature of the display element Z cannot be maintained within the target temperature range below the environmental temperature a, and decreases with the environmental temperature to below the lower limit of 60 ° C. of the target temperature range. On the other hand, at the environmental temperature a, the display elements X and Y can be controlled within the target temperature range. However, if the display elements X and Y are controlled to fall within the target temperature range when the ambient temperature is equal to or lower than the target temperature range, the temperature difference between the display element Z and the display elements X and Y becomes large, and the temperature balance between the display elements is increased. Cannot be maintained. If the temperature balance between the display elements cannot be maintained, the color balance may be lost. Therefore, below the environmental temperature a, the temperatures of the display elements X and Y are controlled to fall within a predetermined range based on the temperature of the display element Z having the lowest temperature. Specifically, the fan for the display element Z is stopped, and the temperatures of the display element X and the display element Y are controlled to be within ± 5 ° C. with respect to the temperature of the display element Z, for example.

  Further, the temperature of the display element X cannot be maintained within the target temperature range above the environmental temperature b, and rises with the environmental temperature and is higher than 70 ° C. which is the upper limit of the target temperature range. On the other hand, at the environmental temperature b, the display elements Y and Z can be controlled within the target temperature range. However, if the display elements Y and Z are controlled so as to be within the target temperature range when the temperature is equal to or higher than the environmental temperature b, the temperature difference between the display elements X and the display elements Y and Z becomes large, and the temperature balance between the display elements is increased. Cannot be maintained. If the temperature balance between the display elements cannot be maintained, the color balance may be lost. Therefore, when the ambient temperature is equal to or higher than the ambient temperature b, the temperatures of the display elements Y and Z are controlled to fall within a predetermined range based on the temperature of the display element X having the highest temperature. Specifically, the temperature of the display element Y and the display element Z is controlled to be, for example, within ± 5 ° C. with respect to the temperature of the display element X while the rotation speed of the fan for the display element X remains the maximum.

  As a result, even if the temperature of at least one of the display elements cannot be maintained within the target temperature range, the temperature difference between the display elements can be reduced and the color balance can be prevented from being disturbed. it can.

  When both display elements can be controlled within the target temperature range, in addition to controlling the temperature of each display element to be within the predetermined temperature range, other display is performed based on the predetermined display element temperature. The temperature of the element may be controlled. For example, the temperature of the Gch display element 221 that is most likely to affect the image quality is controlled to be 60 to 70 ° C., and the temperatures of the Rch display element 161 and the Bch display element 251 are the same as those of the Gch display element 221. However, the temperature may be controlled within ± 5 ° C. By controlling in this way, the temperature balance of each channel can be controlled more accurately.

  In the above-described first and second embodiments, the example in which the temperature of the display element of each channel is controlled to be the same temperature as possible has been shown, but the control target temperature range may be changed for each display element. Generally, Bch display elements deteriorate faster than other display elements because they reflect light that contains a large amount of ultraviolet components.Therefore, by cooling the Bch display element to a temperature slightly lower than that of other display elements, The life of can be extended. Therefore, the target set temperature of the Bch display element may be controlled to be slightly lower (for example, about 5 ° C.) than the Rch display element and the Gch display element.

  Further, in the above-described first and second embodiments, the cooling unit has been described as a configuration in which the fan blows air, but the cooling unit is not limited to the air cooling type, and a water cooling type is also applicable.

  Further, in the above-described first and second embodiments, the color components have been described as three colors of red, green, and blue, but the color components are not limited to this, and, for example, yellow may be added to have four colors.

1 Liquid Crystal Projector 2 Screen 11 Light Source 12, 19 Cross Dichroic Mirror 13, 18 Mirror 14, 20, 23 Relay Lens 15, 21, 24 Polarization Beam Splitter 16 Rch Modulator 17 Color Synthesizing Prism 22 Gch Modulator 25 Bch Modulator 26 Projection lens 27 Control unit 161 Rch display element 162 Rch heat sink 163 Rch fan 164 Rch duct 165 Rch temperature sensor 221 Gch display element 222 Gch heat sink 223 Gch fan 224 Gch duct 225 Gch temperature sensor 251 Bch display element 252 Bch heat sink 253 Bch fan 254 Bch duct 255 Bch temperature sensor

Claims (2)

A plurality of display elements each modulating light of different color components,
A plurality of temperature detection units for detecting the temperature of each of the plurality of display elements,
A plurality of cooling units for cooling each of the plurality of display elements,
A control unit that controls the temperature of each of the plurality of display elements according to the detection results of the plurality of temperature detection units by cooling by the plurality of cooling units;
The control unit is
If the temperature of the display element having the slowest temperature increase rate among the plurality of display elements is less than the predetermined temperature, the temperature of the other display element is set to a predetermined value based on the temperature of the display element having the slowest temperature increase rate. A liquid crystal projector device characterized by being controlled so as to fall within the range. The liquid crystal projector device according to claim 1, wherein the cooling unit is a blower fan, and the control unit controls the rotation speed of the blower fan based on a detection result of the temperature detection unit.

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