JPH1138378A - Spacial light modulation element, and liquid crystal projector using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spacial light modulation element precisely controlling temp. according to real temp. change, and to provide a liquid crystal projector obtaining a stable projection video by using mt. SOLUTION: Temp. sensors 16A, 17A, 18A for detecting a temp. rise caused by incident light are incorporated in the liquid crystal panels 16, 17, 18 of the liquid crystal projector 10. Further, Peltier units 16B, 17B, 18B for adjusting these temp. are stuck/arranged to these main body parts on the liquid crystal panels 16, 17, 18. A temp. control circuit 23 drives the Peltier units 16B, 17B, 18B according to the temp. detected by the temp. sensors 16A, 17A, 18A to control the temp. of respective liquid crystal panels 16, 17, 18 to proper temp.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spatial light modulator for modulating light according to an external video signal and a liquid crystal projector using the same.

[0002]

2. Description of the Related Art As a projector for projecting an image on a screen, for example, a liquid crystal projector 110 using a reflection type liquid crystal panel is known (FIG. 11). The liquid crystal projector 110 includes a light source 1 in a housing 111 thereof.
12, the illumination optical system 113, and the polarization beam splitter 1
14, a cross dichroic mirror 115, three liquid crystal panels 116, 117 and 118, and a projection lens 11
9 are arranged.

In such a liquid crystal projector 110,
The white light emitted from the light source 112 is
3. The liquid crystal panel 11 is divided into three colors of linearly polarized light (S-polarized light) by passing through the polarizing beam splitter 114 and the cross dichroic mirror 115 in this order.
6 to 118 are irradiated. These three liquid crystal panels 11
When each of the S-polarized light irradiated to 6 to 118 is reflected here, a part of the S-polarized light is modulated to P-polarized light according to the video signal given to each of the liquid crystal panels 116 to 118. Modulated light (S + P polarized light) reflected by each of the liquid crystal panels 116 to 118
Passes through the cross dichroic mirror 115 and the polarization beam splitter 114 again in order, so that only the modulation component (P polarization) corresponding to the video signal is
The image is projected on an external screen (not shown) via an interface 19.

By the way, such a liquid crystal projector 1
In the case of 10, most of the white light emitted from the light source 112 is absorbed in the housing 111 without contributing to the projected image on the screen and becomes heat. One of various optical components in the housing 111 that absorbs a lot of light and generates heat is the liquid crystal panels 116 to 118.

Generally, the liquid crystal panels 116 to 118 have a very narrow temperature range (appropriate temperature range) in which the performance can be sufficiently exhibited, and if the temperature rises beyond the appropriate temperature range, a stable projected image cannot be obtained. For this reason, the liquid crystal projector 110 includes a cooling fan 121 for cooling the inside of the housing 111 entirely and a cooling fan 122 for intensively cooling the liquid crystal panels 116 to 118 whose temperature rises sharply. Is installed.

In the liquid crystal projector 110, the cooling fan 12 is simultaneously turned on when its main power is turned on.
The operation of 1,122 is also started, and thereafter, cooling is continuously performed.

[0007]

However, in the liquid crystal projector 110, since the cooling by the cooling fans 121 and 122 is performed uniformly, the temperature rise of the liquid crystal panels 116 to 118 exceeds the capacity of the cooling fan 122, The temperatures of the liquid crystal panels 116 to 118 may exceed the appropriate temperature range. Even in such a case, the liquid crystal projector 110
If the liquid crystal panels 116 to 118 continue to be used, the performance of the liquid crystal panels 116 to 118 themselves deteriorates due to a rise in the temperature of the liquid crystal panels 116 to 118, or the life thereof is shortened.

For this reason, the above-described liquid crystal projector 110
Therefore, even if the liquid crystal projector 110 is used for a long time, the cooling fan 122 for the liquid crystal panels 116 to 118 is set so that the temperature of the liquid crystal panels 116 to 118 does not rise beyond the appropriate temperature range. It consisted of a large blower. Further, in the liquid crystal projector 110, even when the temperature of the liquid crystal panels 116 to 118 is still lower than the appropriate temperature range, such as immediately after the main power is turned on, the operation of the cooling fan 122 is started at the same time as the liquid crystal panel is turned on. The panels 116 to 118 are forcibly cooled (supercooled).

However, in the liquid crystal projector 110,
In order to obtain a stable projection image, the liquid crystal panel 11
It is necessary to warm the temperature of 6 to 118 to an appropriate temperature range (warm-up). However, under the supercooling by the cooling fan 122, the image projected by the liquid crystal projector 110 becomes stable (until the warm-up is completed). The problem is that it takes a considerable amount of time.

Further, a cooling fan 122 having a large air flow rate is provided.
, The size and weight of the liquid crystal projector 110 have been hindered. SUMMARY OF THE INVENTION It is an object of the present invention to provide a spatial light modulator capable of accurately controlling the temperature in accordance with an actual temperature change, and a liquid crystal projector capable of obtaining a stable projected image by using the spatial light modulator.

[0011]

According to a first aspect of the present invention, a temperature sensor is incorporated in a spatial light modulator that modulates incident light in accordance with an externally applied video signal.

According to a second aspect of the present invention, the spatial light modulator according to the first aspect is a liquid crystal panel, and the liquid crystal panel modulates the polarization state of the linearly polarized light incident on the liquid crystal panel according to an externally supplied video signal. Then, the modulated light is emitted. According to a third aspect of the present invention, there is provided a liquid crystal projector using the spatial light modulator according to the second aspect, wherein a voltage corresponding to a video signal is supplied to the liquid crystal panel, and a temperature detected by a temperature sensor. And a voltage correcting means for correcting a voltage corresponding to the video signal based on the video signal.

According to a fourth aspect of the present invention, there is provided a liquid crystal projector using the spatial light modulator according to the second aspect,
Light source means for generating linearly polarized light, and control means for stopping the operation of the light source means when the temperature detected by the temperature sensor is out of a predetermined range. According to a fifth aspect of the present invention, there is provided a liquid crystal projector using the spatial light modulator according to the second aspect, wherein when a temperature detected by a temperature sensor is out of a predetermined range, the fact is notified to the outside. It is provided with a notification means.

According to a sixth aspect of the present invention, there is provided a spatial light modulator for modulating incident light in accordance with an externally supplied video signal, a temperature detecting means for detecting a temperature of the spatial light modulator, Temperature adjusting means for adjusting the temperature of the spatial light modulator based on the temperature detected by the detecting means. According to a seventh aspect of the present invention, the spatial light modulator according to the sixth aspect is a liquid crystal panel, and the liquid crystal panel modulates the polarization state of the incident linearly polarized light according to an externally applied video signal. It emits modulated light.

According to an eighth aspect of the present invention, in the spatial light modulator according to the seventh aspect, the temperature detecting means is a temperature sensor built in a base portion of the liquid crystal panel. According to a ninth aspect of the present invention, in the spatial light modulation element according to the seventh or eighth aspect, the temperature adjusting means includes an electronic cooling / heating element closely attached to a base portion of the liquid crystal panel.

According to a tenth aspect of the present invention, in the spatial light modulator according to the ninth aspect, the liquid crystal panel is a reflective liquid crystal panel that emits modulated light from a plane of incidence of linearly polarized light. Are arranged in close contact with the surface of the liquid crystal panel opposite to the incident surface. According to an eleventh aspect of the present invention, in the spatial light modulator according to the ninth aspect, the liquid crystal panel is a transmissive liquid crystal panel in which a plane of incidence of linearly polarized light and a plane of emission of modulated light face each other. The cooling / heating element is disposed in close contact with a surface other than the entrance surface and the exit surface of the liquid crystal panel.

According to a twelfth aspect of the present invention, in the spatial light modulator according to any one of the ninth to eleventh aspects, the electronic cooling and heating element is a Peltier element. A thirteenth aspect of the present invention is a liquid crystal projector using the spatial light modulator according to any one of the ninth to twelfth aspects, wherein the liquid crystal projector has at least one liquid crystal panel. The one or more liquid crystal panels each have a built-in temperature sensor and an electronic cooling and heating element arranged in close contact therewith, and the temperature adjusting means performs a corresponding electronic cooling based on the temperature detected by the individual temperature sensor. The heating elements are individually driven to individually adjust the temperature of the liquid crystal panel.

(Function) In the spatial light modulator according to the first aspect of the present invention, since the temperature sensor is built in, the temperature rise of the spatial light modulator caused when the incident light is received from the outside. It can be detected with high accuracy.
In the spatial light modulator according to the second aspect,
The temperature sensor built in the liquid crystal panel can accurately detect a temperature rise of the liquid crystal panel itself caused when the incident light is received from the outside.

In the liquid crystal projector according to the third aspect of the present invention, the voltage correcting means corrects a voltage corresponding to a video signal supplied to the liquid crystal panel based on the temperature of the liquid crystal panel detected by the temperature sensor. Therefore, a stable projected image can always be obtained with the corrected voltage according to the temperature change of the liquid crystal panel.

In the liquid crystal projector according to the present invention, when the temperature of the liquid crystal panel detected by the temperature sensor is out of a predetermined range, the control means stops the operation of the light source means. An abnormal rise in temperature can be prevented. In the liquid crystal projector according to the fifth aspect of the present invention, when the temperature of the liquid crystal panel detected by the temperature sensor deviates from a predetermined range, the notifying means informs the fact, so that the temperature of the liquid crystal panel abnormally rises. Can be prevented beforehand.

In the spatial light modulator according to the sixth aspect of the present invention, the temperature adjuster adjusts the temperature of the spatial light modulator based on the temperature of the spatial light modulator detected by the temperature detector. The temperature can be controlled in accordance with the actual temperature change of the spatial light modulator. In the spatial light modulator according to the seventh aspect of the present invention, the temperature adjusting means adjusts the temperature of the liquid crystal panel based on the temperature of the liquid crystal panel detected by the temperature detecting means. Temperature control can be performed according to temperature changes.

In the spatial light modulator according to the present invention, the temperature adjusting means adjusts the temperature of the liquid crystal panel based on the temperature of the liquid crystal panel detected by a temperature sensor built in the liquid crystal panel. Therefore, more accurate temperature control can be performed. In the spatial light modulator according to the ninth aspect of the present invention, the electronic cooling / heating element closely attached to the liquid crystal panel cools / heats the liquid crystal panel based on the temperature of the liquid crystal panel detected by the temperature sensor. In addition, the temperature of the liquid crystal panel can be controlled with good response.

In the spatial light modulator according to the tenth aspect of the present invention, since the electronic cooling / heating element is disposed in close contact with the surface opposite to the incident surface of the reflective liquid crystal panel, the linearly polarized light by the reflective liquid crystal panel can be used. The modulation operation is not hindered by the thermoelectric cooling / heating element.

In the spatial light modulator according to the eleventh aspect of the present invention, the electronic cooling / heating element is closely attached to a surface other than the entrance surface and the exit surface of the transmission type liquid crystal panel. Is not hindered by the electronic cooling / heating element. In the spatial light modulator according to the twelfth aspect, the liquid crystal panel is cooled / heated only by changing the magnitude and direction of the current flowing through the Peltier element based on the temperature of the liquid crystal panel detected by the temperature sensor. Temperature control of the liquid crystal panel becomes easy.

In the liquid crystal projector according to the thirteenth aspect of the present invention, the electronic cooling and heating elements individually arranged on the liquid crystal panel are individually based on the temperatures detected by the temperature sensors built in the individual liquid crystal panels. Since the liquid crystal panel is driven, it is possible to control the temperature of the liquid crystal panel with high accuracy according to the temperature change of each liquid crystal panel.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a diagram showing the overall configuration of a liquid crystal projector 10 according to a first embodiment. In the first embodiment, claims 6 to 10, claim 12,
This corresponds to claim 13. As shown in FIG. 1, a liquid crystal projector 10 according to the first embodiment includes
A light source 12, an illumination optical system 13, a polarization beam splitter 14, a cross dichroic mirror 15, and three liquid crystal panels 16, 17, each having a temperature detecting means, are provided.
18 (spatial light modulation element), a projection lens 19, a cooling fan 21, and a temperature control circuit 23.

The polarization beam splitter 14 is disposed on the optical path L1 of the white light emitted from the light source 12. A cross dichroic mirror 15 is disposed on the optical path L2 of the S-polarized light reflected by the polarization beam splitter 14. The cross dichroic mirror 15 splits incident white light (S-polarized light) into three optical paths L6, L7, and L8 according to the wavelength. Among them, the liquid crystal panel 16 is disposed on the optical path L6 of red (R) light, the liquid crystal panel 17 is disposed on the optical path L7 of blue (B) light, and the liquid crystal panel 17 is disposed on the optical path L8 of green (G) light. A liquid crystal panel 18 is provided. These liquid crystal panels 16, 1
Reference numerals 7 and 18 denote R components provided to liquid crystal driving circuits 34a, 34b and 34c of the liquid crystal panels 16, 17 and 18, respectively.
In response to the video signals for the B component and the G component, the incident S
A part of the polarized light is modulated into P-polarized light and reflected.

The projection lens 19 is disposed on the opposite side of the cross dichroic mirror 15 with the deflection beam splitter 14 interposed therebetween. The projection lens 19 reflects a component (P-polarized light) of the modulated light (S + P-polarized light) reflected by the liquid crystal panels 16 to 18 and then synthesized by the cross dichroic mirror 15 again. ) Is projected onto an external screen (not shown).

Next, the specific structure of the liquid crystal panels 16 to 18 each provided with a temperature detecting means will be described.
FIG. 2 is a diagram showing a specific configuration of the liquid crystal panel 16 among them. As shown in FIG. 2, the liquid crystal panel 16 is configured such that a light-transmitting substrate 31 is
A space is opened on the top and bonded.
Are filled. Note that a transparent electrode 31c and a transparent electrode 33c are formed on the opposing surfaces 31b and 33b of the translucent substrate 31 and the base portion 33, respectively. Further, a reflection film 33d is formed between the base 33 and the transparent electrode 33c.

The base 33 of the liquid crystal panel 16 includes
A liquid crystal drive circuit 34a is built in (this connection is not shown). The liquid crystal drive circuit 34a is connected to the transparent electrodes 31c and 33c and applies a voltage corresponding to an externally supplied R component video signal to the transparent electrodes 31c and 33c.
c and 33c to change the alignment state of the liquid crystal 16C.

Further, a concave portion 33e is formed in the base portion 33 of the liquid crystal panel 16, and the liquid crystal panel 1 is formed in the concave portion 33e.
A temperature sensor 16A (temperature detecting means) for directly detecting the temperature of No. 6 is provided. This temperature sensor 16A
Is connected to an output terminal 36 by a lead wire 35 embedded in the base 33, and a temperature signal (T1) indicating the temperature of the liquid crystal panel 16 detected by the temperature sensor 16A is transmitted through the output terminal 36. Output to a temperature control circuit 23 described later.

Further, the base portion 33 of the liquid crystal panel 16
The Peltier unit 16B is arranged in close contact with the back surface 33a. The Peltier unit 16B is composed of a plurality (five in FIG. 2) of Peltier elements 41, 41,... Each Peltier element 41 (a portion surrounded by a broken line in FIG. 2) is formed by joining a pair of a P-type semiconductor 43 and an N-type semiconductor 44 with a copper electrode 45b. Also,
The plurality of Peltier elements 41, 41,.
Are electrically connected in series with each other, and unit terminals 16x and 16y are connected to the Peltier elements 41, 41 at both ends of the row, respectively. These unit terminals 16x and 16y are connected to a temperature control circuit 2 described later.
3 is connected. Here, the Peltier unit 16B and the temperature control circuit 23 function as temperature adjusting means.

Such a plurality of Peltier devices 41, 4
In the Peltier unit 16B composed of 1,..., The copper electrode 45b for joining the P-type semiconductor 43 and the N-type semiconductor 44 of each Peltier element 41 is provided on the back surface 33a of the base 33 of the liquid crystal panel 16 via the copper plate 47b. They are arranged in close contact. Further, radiation fins 42 are attached to copper electrodes 45a, 45a,... Which connect a plurality of Peltier elements 41, 41, in series via a copper plate 47a.

In such a Peltier unit 16B,
The direction from the unit terminal 16x to the unit terminal 16y (FIG. 2)
In the direction indicated by the thick solid line),
A copper electrode 45b closely attached to the base 33 of the liquid crystal panel 16,
45b,... Absorb heat, and generate heat at the copper electrodes 45a, 45a,. Therefore, in this case, the liquid crystal panel 16 is cooled by the Peltier unit 16B. Hereinafter, the direction of the current from the unit terminal 16x to the unit terminal 16y is referred to as a cooling direction.

Conversely, when a DC current flows in the direction from the unit terminal 16y to the unit terminal 16x (the direction indicated by the thick broken line in FIG. 2), the Peltier unit 16B comes into close contact with the base 33 of the liquid crystal panel 16. Copper electrode 45
Generate heat at b, 45b,... and absorb heat at copper electrodes 45a, 45a,.
Therefore, in this case, the liquid crystal panel 16 is heated by the Peltier unit 16B. Hereinafter, the direction of the current from the unit terminal 16y to the unit terminal 16x is referred to as a heating direction.

In the above-mentioned liquid crystal panel 16, a heat insulating material 37 is filled between the temperature sensor 16A and the Peltier unit 16B. Thus, the transmission of heat from the Peltier unit 16B to the temperature sensor 16A is shut off. The liquid crystal panel 16 shown in FIG. 1 is configured as described above. Further, the B light having a different wavelength from the R light incident on the liquid crystal panel 16 is incident on the liquid crystal panel 17 shown in FIG. Therefore, the liquid crystal panel 1
7, the temperature rise due to the incidence of the B light causes the liquid crystal panel 1
It is different from 6. Therefore, the liquid crystal panel 17
Has a built-in temperature sensor 17A, which directly detects the temperature of the liquid crystal panel 17. Since the configuration of the liquid crystal panel 17 is the same as that of the liquid crystal panel 16 described above, detailed illustration and description are omitted.

Further, the liquid crystal panel 18 shown in FIG.
G light having a wavelength different from that of the B light that is incident on the.
Therefore, the temperature rise due to the incidence of the G light on the liquid crystal panel 18 is different from that of the liquid crystal panels 16 and 17. For this reason, the liquid crystal panel 18 has a temperature sensor 18A.
And directly detects the temperature of the liquid crystal panel 18. Since the configuration of the liquid crystal panel 18 is the same as that of the liquid crystal panel 16 described above, detailed illustration and description are omitted.

As in the case of the liquid crystal panel 16, these liquid crystal panels 17 and 18 have a B component and a G component, respectively, between two transparent electrodes (not shown) sandwiching the liquid crystals 17C and 18C. The liquid crystal drive circuits 34b and 34c for supplying a voltage corresponding to the video signal are built in. Next, the internal configuration of the temperature control circuit 23 will be described. This temperature control circuit 23, as shown in FIG.
The converter 231, the CPU 232, the ROM 233, and the D
/ A converter 234 and a current driver 235.

The CPU 232 includes the A / D converter 2
31 through the three temperature sensors 16A, 17A, 18
A output terminal, while the D / A converter 234
Is connected to the current driver 235 via the. Further, the CPU 232 has a ROM 23 via a data bus.
3 are connected. The ROM 233 stores an appropriate temperature range for the liquid crystal 16C of the liquid crystal panel 16 for R, an appropriate temperature range for the liquid crystal 17C of the liquid crystal panel 17 for B,
8 and the appropriate temperature range for G of the liquid crystal 18C are individually stored in advance.

The current driver 235 has 3
Terminals (16x, 16y), (17x, 17y) of the two Peltier units 16B, 17B, 18B.
y) and (18x, 18y) are connected. Next, the temperature control of the liquid crystal projector 10 by the above-described temperature control circuit 23 will be specifically described.

As shown in FIG. 3, a temperature signal T1 representing the temperature of the liquid crystal panel 16 detected by the temperature sensor 16A and a temperature signal
A temperature signal T2 indicating the temperature of the liquid crystal panel 17 detected by A and a temperature signal T3 indicating the temperature of the liquid crystal panel 18 detected by the temperature sensor 18A are input.

The temperature signals T1 to T3 (analog signals) from the temperature sensors 16A to 18A are converted into digital signals via an A / D converter 231 in the temperature control circuit 23, and then input to the CPU 232, respectively. You. At this time CP
U232 determines whether the temperature of the liquid crystal panel 16 is within the appropriate temperature range for R stored in the ROM 233, lower than the appropriate temperature range for R, or based on the temperature signal T1 from the temperature sensor 16A. It is determined whether the temperature is higher than the appropriate temperature range, and based on the result of this determination, a control signal (digital signal) indicating the direction and amount of current to be passed to the Peltier unit 16B is output.

This control signal is converted into an analog signal via a D / A converter 234, and then converted into a current driver 235.
And amplified by the current driver 235 and output. In this case, when the temperature of the liquid crystal panel 16 is higher than the appropriate temperature range for R, a direct current in the cooling direction is supplied from the current driver 235 to the Peltier unit 16B.
At this time, the liquid crystal panel 16 is cooled.

When the temperature of the liquid crystal panel 16 is lower than the appropriate temperature range for R, a direct current in the heating direction is supplied from the current driver 235 to the Peltier unit 16B. At this time, the liquid crystal panel 16 is heated. Note that, based on the temperature signal T1 from the temperature sensor 16A, the CPU
If the 232 determines that the temperature of the liquid crystal panel 16 is within the appropriate temperature range for R, no DC current flows from the current driver 235 to the Peltier unit 16B. Therefore, the liquid crystal panel 16 is neither cooled nor heated.

As described above, the temperature control circuit 23 controls the temperature of the liquid crystal panel 16 by passing a DC current to the Peltier unit 16B based on the temperature signal T1 from the temperature sensor 16A. Other liquid crystal panel 1
The temperature control of 7 and 18 is performed. That is, the liquid crystal panel 17
CPU 232 controls the temperature sensor 1
Based on the temperature signal T2 from 7A, the temperature of the liquid crystal panel 17 is within the appropriate temperature range for B stored in the ROM 233, lower than the appropriate temperature range for B, or lower than the appropriate temperature range for B. It is determined whether the current is high or not, and based on the result of this determination, a control signal indicating the direction and amount of current to be passed to the Peltier unit 17B is output. This control signal is sent to the current driver 235 via the D / A converter 234, and is amplified and output by the current driver 235.

In this case, when the temperature of the liquid crystal panel 17 is higher than the appropriate temperature range for B, a direct current in the cooling direction is supplied from the current driver 235 to the Peltier unit 17B, and the liquid crystal panel 17 is cooled. When the temperature of the liquid crystal panel 17 is lower than the appropriate temperature range for B, a direct current in the heating direction is supplied from the current driver 235 to the Peltier unit 17B, and the liquid crystal panel 17 is heated. When the CPU 232 determines that the temperature of the liquid crystal panel 17 is within the appropriate temperature range for B based on the temperature signal T2 from the temperature sensor 17A, the direct current is supplied from the current driver 235 to the Peltier unit 17B. Not flowing. Therefore, the liquid crystal panel 17 is neither cooled nor heated.

As for the temperature control of the liquid crystal panel 18, the CPU 232 controls the temperature of the liquid crystal panel 18 based on the temperature signal T3 from the temperature sensor 18A.
3 is determined to be within the appropriate temperature range for G, lower than the appropriate temperature range for G, or higher than the appropriate temperature range for G. Based on the result of this determination, the Peltier unit 18B And outputs a control signal indicating the direction and amount of the current to be passed through the control circuit. This control signal is supplied to the D / A converter 23
4 is sent to the current driver 235, and is amplified and output by the current driver 235.

In this case, when the temperature of the liquid crystal panel 18 is higher than the appropriate temperature range for G, a direct current in the cooling direction is supplied from the current driver 235 to the Peltier unit 18B, and the liquid crystal panel 18 is cooled. When the temperature of the liquid crystal panel 18 is lower than the appropriate temperature range for G, a direct current in the heating direction is supplied from the current driver 235 to the Peltier unit 18B, and the liquid crystal panel 18 is heated. When the CPU 232 determines that the temperature of the liquid crystal panel 18 is within the appropriate G temperature range based on the temperature signal T3 from the temperature sensor 18A, the direct current is supplied from the current driver 235 to the Peltier unit 18B. Not flowing. Therefore, the liquid crystal panel 18 is neither cooled nor heated.

As described above, in the liquid crystal projector 10 of the first embodiment, the temperature sensors 16A to 18A are built in the liquid crystal panels 16 to 18, respectively.
-18 can be directly detected. Therefore, even when the temperature rise differs for each of the liquid crystal panels 16 to 18, the temperature of each of the liquid crystal panels 16 to 18 can be accurately detected.

The liquid crystal projector 1 according to the first embodiment
In the case of 0, the Peltier units 16B to 18B are arranged in close contact with the back surfaces of the liquid crystal panels 16 to 18, so that temperature adjustment such as cooling and heating of the liquid crystal panels 16 to 18 can be performed individually. Further, in the liquid crystal projector 10 of the first embodiment, the temperatures of the liquid crystal panels 16 to 18 are directly detected by the respective temperature sensors 16A to 18A, and based on the detected accurate temperatures, the Peltier units 16B to
18B are individually driven, the temperature of the liquid crystal panel 16 is always within the appropriate temperature range for R, the temperature of the liquid crystal panel 17 is always within the appropriate temperature range for B, and the temperature of the liquid crystal panel 18 is always within the appropriate temperature range for G. Can be kept within. Therefore,
The projected image of the liquid crystal projector 10 is always stable.

The liquid crystal projector 1 of the first embodiment
0, when the temperatures of the liquid crystal panels 16 to 18 are within the respective appropriate temperature ranges, the Peltier units 16B to 18
B to prevent DC current from flowing through the liquid crystal panel 1
Since neither 6 nor 18 is cooled or heated, power consumption can be reduced. In the liquid crystal projector 10 of the first embodiment, only the direction of the DC current flowing through the Peltier units 16B to 18B is changed. However, by changing the amount of the DC current flowing through the Peltier units 16B to 18B according to the detected temperature. The heat absorption and heat generation of the liquid crystal panels 16 to 18 by the Peltier units 16B to 18B can be freely changed. In this case, the liquid crystal panels 16A-1A
The degree of cooling or heating of 8A can be finely adjusted according to the amount of deviation of the temperature of liquid crystal panels 16-18 from the optimum temperature.

The liquid crystal projector 1 according to the first embodiment
0, a cooling fan for intensively cooling the liquid crystal panels 16 to 18 is not required.
The overall size and weight can also be reduced. (Second Embodiment) Next, a liquid crystal projector 50 according to a second embodiment will be described with reference to FIGS. The second embodiment corresponds to claims 1 to 3, claims 6 to 10, claim 12, and claim 13.

As shown in FIG. 4, the liquid crystal projector 50 according to the second embodiment has a light source 12 and a light source 12 inside a housing 11 similarly to the liquid crystal projector 10 according to the first embodiment.
An illumination optical system 13, a polarizing beam splitter 14, a cross dichroic mirror 15, three liquid crystal panels 16, 17, 18 each having a temperature detecting means, a projection lens 19, a cooling fan 21, a temperature control The circuit 53 is arranged. In FIG. 4, the same components as those of the liquid crystal projector 10 according to the first embodiment are denoted by the same reference numerals. The liquid crystal projector 50 according to the second embodiment, based on temperature signals from temperature sensors 16A to 18A incorporated in three liquid crystal panels 16 to 18,
While driving the Peltier units 16B to 18B, the liquid crystal driving circuits 34a to 34c output the respective liquid crystals 16C to 18C.
C, two transparent electrodes (the transparent electrode 31 shown in FIG. 1).
The liquid crystal projector 10 according to the first embodiment is different from the liquid crystal projector 10 of the first embodiment in that a temperature control circuit 53 for correcting a voltage (liquid crystal drive voltage) supplied between (c, 33c) is provided instead of the temperature control circuit 23.

In the temperature control circuit 53, the liquid crystal driving voltage supplied to each of the liquid crystal panels 16 to 18 from the liquid crystal driving circuits 34a to 34c is corrected because an ideal voltage for obtaining a stable projected image is obtained. , Liquid crystal panel 16-1
This is because the temperature changes according to the temperature of No. 8. Temperature control circuit 53 provided in liquid crystal projector 50 of the second embodiment
Is, as shown in FIG. 5, an A / D converter 231 and C
PU532, ROM533, D / A converter 234
, A current driver 235, and an output unit 536. In FIG. 5, the same components as those of the temperature control circuit 23 of the liquid crystal projector 10 of the first embodiment are denoted by the same reference numerals. The CPU 532 includes three temperature sensors 16 </ b> A, 17 </ b> A through the A / D converter 231.
18A, while the D / A converter 2
It is connected to a current driver 235 via.

The current driver 235 has unit terminals (16x, 16y), (17x, 17y), (18x) of the three Peltier units 16B, 17B, 18B.
x, 18y) are connected. Further, the CPU 532
Is connected to a ROM 533 via a data bus. The ROM 533 stores the liquid crystal 16 of the liquid crystal panel 16.
C temperature range for R and the liquid crystal 17C of the liquid crystal panel 17
The appropriate temperature range for B and the appropriate temperature range for G of the liquid crystal 18C of the liquid crystal panel 18 are separately stored in advance, and the deviation amounts (ΔT1 to ΔT1) of the temperatures T1 to T3 of the liquid crystal panels 16 to 18 from the reference temperature are stored. ΔT3) and voltage correction values (Vd1 to Vd)
3) is stored.

The liquid crystal driving circuits 34a to 34c for the three liquid crystal panels 16 to 18 are connected to the CPU 532 via an output unit 536. Next, the temperature control of the liquid crystal projector 50 by the temperature control circuit 53 will be specifically described. The temperature control circuit 53
However, the Peltier units 16B to 18B are driven based on the temperature signals from the temperature sensors 16A to 18A, but the driving method is the same as that of the liquid crystal projector 10 of the first embodiment, and the description thereof will be omitted.

As shown in FIG. 5, the temperature control circuit 53 includes a temperature signal T1 representing the temperature of the liquid crystal panel 16 detected by the temperature sensor 16A and a temperature sensor 17
A temperature signal T2 indicating the temperature of the liquid crystal panel 17 detected by A and a temperature signal T3 indicating the temperature of the liquid crystal panel 18 detected by the temperature sensor 18A are input.

The temperature signals T1 to T3 from the temperature sensors 16A to 18A are sent to the A / D converter 2 in the temperature control circuit 53.
After being converted into digital data through the interface 31, they are input to the CPU 532. At this time, the CPU 532
Based on the temperature signal T1 from 6A, a deviation ΔT1 of the temperature (T1) of the liquid crystal panel 16 from the reference temperature is obtained.
Here, the reference voltage is a temperature condition for determining an ideal voltage for obtaining a stable projected image based on an external influence.

Then, the CPU 532 further reads the ROM 5
Based on the correction table stored in 33, a voltage correction value Vd1 corresponding to the calculated temperature deviation ΔT1 of the liquid crystal panel 16 is read. The correction signal representing the voltage correction value Vd1 is output via the output unit 536 to the liquid crystal drive circuit 34a.
Is output to The liquid crystal drive circuit 34a determines the level V1 of the liquid crystal drive voltage to be supplied to the liquid crystal panel 16 in accordance with the R component video signal supplied from the outside, and, in response to the determined level V1, the temperature control circuit 53 , And supplies the corrected liquid crystal drive voltage to the liquid crystal panel 16.

As described above, in the temperature control circuit 53, the liquid crystal driving circuit 3 is controlled based on the temperature signal from the temperature sensor 16A.
Although the liquid crystal driving voltage is corrected by the reference numeral 4a, the voltage correction is performed separately on the other liquid crystal panels 17 and 18 in the same procedure. That is, the liquid crystal panel 1
Regarding the voltage correction for 7, the CPU 532 obtains the deviation amount ΔT2 from the reference temperature based on the temperature signal T2 from the temperature sensor 17A.

Then, the CPU 532 further stores in the ROM 5
Based on the correction table stored in 33, a voltage correction value Vd2 corresponding to the calculated temperature deviation ΔT2 of the liquid crystal panel 17 is read. The correction signal representing the voltage correction value Vd2 is output via the output unit 536 to the liquid crystal drive circuit 34b.
Is output to The liquid crystal drive circuit 34b determines the level V2 of the liquid crystal drive voltage to be supplied to the liquid crystal panel 17 in accordance with the B component video signal supplied from the outside, and performs a temperature control circuit 53 on the determined level V2. , And supplies the corrected liquid crystal drive voltage to the liquid crystal panel 17.

As for the voltage correction for the liquid crystal panel 18, the CPU 532, based on the temperature signal T3 from the temperature sensor 18A, calculates the deviation ΔT from the reference temperature.
Ask for 3. Then, the CPU 532 further reads the ROM 5
Based on the correction table stored in 33, a voltage correction value Vd3 corresponding to the calculated temperature deviation ΔT3 of the liquid crystal panel 18 is selected. The correction signal representing the voltage correction value Vd3 is output via the output unit 536 to the liquid crystal drive circuit 34c.
Is output to

The liquid crystal drive circuit 34c determines the level V3 of the liquid crystal drive voltage supplied to the liquid crystal panel 18 according to the G component video signal supplied from the outside,
The determined level V3 is corrected based on a correction signal (Vd3) from the temperature control circuit 53, and the corrected liquid crystal drive voltage is supplied to the liquid crystal panel 18.

As described above, in the liquid crystal projector 50 of the second embodiment, the temperatures (T1 to T3) of the liquid crystal panels 16 to 18 detected by the temperature sensors 16A to 18A.
In addition to adjusting the temperatures of the liquid crystal panels 16 to 18 according to the temperature, the temperatures (T1 to T
If 3) deviates from the reference temperature, the liquid crystal panel 16
Liquid crystal drive voltage V1 corresponding to the video signal supplied to.
To V3 are corrected in accordance with the amount of temperature deviation (ΔT1 to ΔT3), so that a stable projected image can always be obtained irrespective of the temperature change of each of the liquid crystal panels 16 to 18.

Third Embodiment Next, a liquid crystal projector 60 according to a third embodiment will be described with reference to FIGS. In the third embodiment, claims 1, claim 2, claim 4, claims 6 to 10, claim 12, and claim 13 are provided.
Corresponding to As shown in FIG. 6, a liquid crystal projector 60 according to the third embodiment includes a light source 12 in a housing 11 thereof, like the liquid crystal projector 10 according to the first embodiment.
An illumination optical system 13, a polarizing beam splitter 14, a cross dichroic mirror 15, three liquid crystal panels 16, 17, 18 each having a temperature detecting means, a projection lens 19, a cooling fan 21, a temperature control The circuit 63 is arranged. In FIG. 6, the same components as those of the liquid crystal projector 10 according to the first embodiment are denoted by the same reference numerals. The liquid crystal projector 60 of the third embodiment drives the Peltier units 16B to 18B based on the temperature signals T1 to T3 from the temperature sensors 16A to 18A incorporated in the three liquid crystal panels 16 to 18, and detects the signals. The liquid crystal projector 10 differs from the liquid crystal projector 10 of the first embodiment in that a temperature control circuit 63 for forcibly turning off the light source 12 based on the temperature signals T1 to T3 is provided instead of the temperature control circuit 23.

The reason why the light source 12 is forcibly turned off in the temperature control circuit 63 is that when the temperature of the liquid crystal panels 16 to 18 exceeds a predetermined temperature, the performance of the liquid crystal panels 16 to 18 themselves deteriorates or the life is shortened. It is because it is done.
As shown in FIG. 7, the temperature control circuit 63 provided in the liquid crystal projector 60 of the third embodiment includes an A / D converter 231, a CPU 632, a ROM 633, a D / A converter 234, a current driver 235 and an output unit 636. In FIG. 7, the same components as those of the temperature control circuit 23 of the liquid crystal projector 10 of the first embodiment are denoted by the same reference numerals.

The CPU 632 includes the A / D converter 2
31 through the three temperature sensors 16A, 17A, 18
A output terminal, while the D / A converter 234
Is connected to the current driver 235 via the. In addition, the current driver 235 has three Peltier units 16B, 17B, 18B with unit terminals (16x,
16y), (17x, 17y), (18x, 18y) are connected.

Further, a ROM 633 is connected to the CPU 632 via a data bus. This ROM 63
3, an appropriate temperature range for R, an appropriate temperature range for B, and an appropriate temperature range for G of the liquid crystal panels 16, 17, and 18 are individually stored in advance, and the unusable temperature of each of the liquid crystal panels 16, 17, and 18 is stored. TM1, TM2, and TM3 are stored.
Each of the unusable temperatures TM1 to TM3 is set to a value higher than any of the upper limit values of the appropriate temperature range for R, the appropriate temperature range for B, and the appropriate temperature range for G.

The light source circuit 12 A of the light source 12 is connected to the CPU 632 via the output unit 636.
The main power supply of the liquid crystal projector 60 is connected to the light source circuit 12A of the light source 12 (this connection relationship is not shown in FIG. 6). Next, the temperature control of the liquid crystal projector 60 by the temperature control circuit 63 will be specifically described. The temperature control circuit 6
Also in 3, the Peltier units 16B to 18B are driven based on the temperature signals from the temperature sensors 16A to 18A. However, the driving method is the same as that of the liquid crystal projector 10 of the first embodiment, and the description thereof will be omitted. .

As shown in FIG. 7, a temperature signal T1 indicating the temperature of the liquid crystal panel 16 detected by the temperature sensor 16A and a temperature sensor 17
A temperature signal T2 indicating the temperature of the liquid crystal panel 17 detected by A and a temperature signal T3 indicating the temperature of the liquid crystal panel 18 detected by the temperature sensor 18A are input.

The temperature signals T1 to T3 from the temperature sensors 16A to 18A are sent to the A / D converter 2 in the temperature control circuit 63.
After being converted into a digital signal through the
2, respectively. At this time, the CPU 632 determines whether or not the temperature (T1) of the liquid crystal panel 16 exceeds the unusable temperature TM1 stored in the ROM 633 based on the temperature signal T1 from the temperature sensor 16A. Is exceeded, the command signal indicating that the light source 12 is forcibly turned off is output to the light source circuit 12A of the light source 12 via the output unit 636.

The CPU 632 includes a temperature sensor 17A.
It is determined whether or not the temperature of the liquid crystal panel 17 exceeds the unusable temperature TM2 based on the temperature signal T2 from
If the temperature exceeds the unusable temperature TM2, the light source 1
2 is output to the output unit 63.
6 to the light source circuit 12A of the light source 12. Further, the CPU 632 determines whether or not the temperature of the liquid crystal panel 18 exceeds the unusable temperature TM3 based on the temperature signal T3 from the temperature sensor 18A.
If the value exceeds M3, a command signal indicating that the light source 12 is forcibly turned off is output to the light source circuit 12A of the light source 12 via the output unit 636.

As described above, in the liquid crystal projector 60 of the third embodiment, the temperature of the liquid crystal panels 16 to 18 is adjusted according to the temperatures (T1 to T3) of the liquid crystal panels 16 to 18 detected by the temperature sensors 16A to 18A. Not only the temperature of any of the three liquid crystal panels 16 to 18 (T1
When T3) exceeds the unusable temperatures TM1 to TM3, the light source 12 is forcibly turned off even if the main power supply is turned on. 16-18 are destroyed,
It is possible to prevent the performances of the liquid crystal panels 16 to 18 themselves from being deteriorated and from shortening the service life.

In the liquid crystal projector 60 of the third embodiment, when one of the temperatures (T1 to T3) of the three liquid crystal panels 16 to 18 exceeds the unusable temperatures TM1 to TM3, the light source 12 is forcibly turned off. Even if the projection operation of the image is interrupted by the temporary turning off, the main power supply of the liquid crystal projector 60 is on, so that the Peltier units 16B to 18B
The cooling of the liquid crystal panels 16 to 18 is continued.

(Fourth Embodiment) Next, a liquid crystal projector 70 according to a fourth embodiment will be described with reference to FIGS. In the fourth embodiment, claim 1, claim 2, claim 5, claim 6 to claim 10, claim 12, and claim 13 are provided.
Corresponding to As shown in FIG. 8, a liquid crystal projector 70 according to the fourth embodiment includes a light source 1 inside a housing 11 thereof.
2, an illumination optical system 13, and a polarizing beam splitter 14
, A cross dichroic mirror 15, and three liquid crystal panels 16, 17, 18 each provided with a temperature detecting means.
, A projection lens 19, a cooling fan 21, a temperature control circuit 73, and an alarm lamp 74. In FIG. 8, the same components as those of the liquid crystal projector 10 of the first embodiment are denoted by the same reference numerals. The liquid crystal projector 70 of the fourth embodiment has a temperature sensor 16A built in three liquid crystal panels 16 to 18.
The Peltier units 16B to 18B are driven based on the temperature signals T1 to T3 from the liquid crystal panels 16 to 18A based on the detected temperature signals T1 to T3.
When the temperature of 8 becomes higher than a predetermined temperature, an alarm lamp 7
4 is different from the liquid crystal projector 10 of the first embodiment in that a temperature control circuit 73 for lighting 4 is provided in place of the temperature control circuit 23.

The reason why the alarm lamp 74 is turned on in the temperature control circuit 73 is that when the temperature of the liquid crystal panels 16 to 18 exceeds a predetermined temperature, the performance of the liquid crystal panels 16 to 18 themselves deteriorates or the life is shortened. This is to notify the operator or the like in some cases. Temperature control circuit 73 provided in liquid crystal projector 70 of the fourth embodiment
Is, as shown in FIG. 9, an A / D converter 231 and C
PU 732, ROM 733, D / A converter 234
, A current driver 235, and an output unit 736. In FIG. 9, the same components as those of the temperature control circuit 23 of the liquid crystal projector 10 of the first embodiment are denoted by the same reference numerals.

The CPU 732 includes the A / D converter 2
31 through the three temperature sensors 16A, 17A, 18
A output terminal, while the D / A converter 234
Is connected to the current driver 235 via the. In addition, the current driver 235 has three Peltier units 16B, 17B, 18B with unit terminals (16x,
16y), (17x, 17y), (18x, 18y) are connected.

Further, a ROM 733 is connected to the CPU 732 via a data bus. This ROM 73
3, an appropriate temperature range for R, an appropriate temperature range for B, and an appropriate temperature range for G of the liquid crystal panels 16, 17, and 18 are individually stored in advance, and the unusable temperature of each of the liquid crystal panels 16, 17, and 18 is stored. TN1, TN2, and TN3 are stored.
Each of the unusable temperatures TN1 to TN3 is set to a value higher than any of the upper limits of the appropriate temperature range for R, the appropriate temperature range for B, and the appropriate temperature range for G.

A control circuit 74 A for the alarm lamp 74 is connected to the CPU 732 via an output unit 736. Next, the temperature control of the liquid crystal projector 70 by the temperature control circuit 73 will be specifically described. Note that the temperature control circuit 73 also uses the temperature sensors 16A to 18A.
A based on the temperature signal from A
Although the driving of 18B is performed, the driving method is the same as that of the liquid crystal projector 10 of the first embodiment, and the description thereof will be omitted.

As shown in FIG. 9, a temperature signal T1 representing the temperature of the liquid crystal panel 16 detected by the temperature sensor 16A and a temperature sensor 17
A temperature signal T2 indicating the temperature of the liquid crystal panel 17 detected by A and a temperature signal T3 indicating the temperature of the liquid crystal panel 18 detected by the temperature sensor 18A are input.

The temperature signals T1 to T3 from the temperature sensors 16A to 18A are sent to the A / D converter 2 in the temperature control circuit 73.
After being converted into a digital signal through the
2, respectively. At this time, the CPU 732 determines whether or not the temperature of the liquid crystal panel 16 exceeds the unusable temperature TN1 stored in the ROM 733 based on the temperature signal T1 from the temperature sensor 16A.
If the value exceeds 1, a command signal indicating that the alarm lamp 74 is turned on is output to the control circuit 74A of the alarm lamp 74 via the output unit 736. The alarm lamp 74 that has received the command from the control circuit 74A turns on the alarm lamp 74 so as to notify the operator of an abnormal temperature rise.

The CPU 732 is connected to the temperature sensor 17A.
It is determined whether the temperature of the liquid crystal panel 17 exceeds the unusable temperature TN2 based on the temperature signal T2 from
When the temperature exceeds the value of the unusable temperature TN2, a command signal indicating that the alarm lamp 74 is turned on is output to the output unit 736.
Is output to the control circuit 74A of the alarm lamp 74 through the control circuit 74 to turn on the alarm lamp 74.

Further, the CPU 732 controls the temperature sensor 18
Based on the temperature signal T3 from A, it is determined whether or not the temperature (T3) of the liquid crystal panel 18 exceeds the unusable temperature TN3. If the temperature (T3) exceeds the value of the unusable temperature TN3, an alarm lamp A command signal indicating that the alarm lamp 74 is turned on is output to the control circuit 74A of the alarm lamp 74 via the output unit 736, and the alarm lamp 74 is turned on.

As described above, in the liquid crystal projector 70 of the fourth embodiment, not only the temperature of the liquid crystal panels 16 to 18 is adjusted according to the temperatures of the liquid crystal panels 16 to 18 detected by the temperature sensors 16A to 18A, but also Any one of the three liquid crystal panels 16 to 18 has an unusable temperature TN1
Since the alarm lamp 74 is turned on when the temperature exceeds TN3, the operator is notified that an abnormal temperature rise has occurred in the liquid crystal panels 16 to 18, and the abnormal temperature of the liquid crystal panels 16 to 18 is notified. A rise can be prevented. As a result, the liquid crystal panel 16
To 18 can be prevented, the performance of the liquid crystal panels 16 to 18 itself can be reduced, and the life can be shortened.

In the liquid crystal projector 70 of the fourth embodiment, an alarm lamp 74 is provided as a means for notifying that an abnormal temperature rise has occurred in the liquid crystal panels 16 to 18 to the outside. The same effect can be obtained by providing. As described above, in the first to fourth embodiments, the temperature sensors (16A to 18A) are built in the reflective liquid crystal panels (16 to 18), and the Peltier units (16B to 18B) are arranged in close contact. Therefore, the temperature of the reflective liquid crystal panel can be accurately controlled according to the actual temperature change.

In the first to fourth embodiments described above, the case where the present invention is applied to the reflection type liquid crystal panels (16 to 18) has been described as an example. However, even when the invention is applied to the transmission type liquid crystal panels. Similar effects can be obtained. For example, if the present invention is applied to the transmissive liquid crystal panel 80 shown in FIG. 10, the temperature sensor 81 is embedded in the base 83 of the transmissive liquid crystal panel 80, and the temperature sensor 81
The Peltier unit 82 may be driven according to the temperature signal from the Peltier unit 82.

In attaching the Peltier unit 82 to the transmissive liquid crystal panel 80, as shown in the figure, the Peltier unit 82 is provided on the side surface of the transmissive liquid crystal panel 80 so as to surround a portion 84 filled with liquid crystal. May be arranged in close contact with each other. Further, the output terminal 81a of the temperature sensor 81 of the transmissive liquid crystal panel 80 and the Peltier unit 8
2 and the signal terminals 8x and 82y.
0a, connects to a temperature control circuit, not shown,
By this temperature control circuit, similarly to the temperature control circuit 23 of the above-described first embodiment, the direct current in the cooling direction or the heating direction is supplied to the Peltier unit 82 based on the accurate temperature of the liquid crystal panel 80 detected by the temperature sensor 81. If a current is passed, the temperature of the liquid crystal panel 80 can always be kept within an appropriate temperature range.

In the above-described first to fourth embodiments, the Peltier units (16B to 18B) closely attached to the liquid crystal panels (16 to 18) are connected to the temperature sensors (16A to 1B).
8A), a cooling fan for intensively cooling the liquid crystal panel is provided instead of closely attaching the Peltier unit to the liquid crystal panel, and the cooling fan is connected to a temperature sensor. May be controlled by a temperature signal from the controller. Further, a Peltier unit and a cooling fan may be provided in the liquid crystal projector, and both may be controlled by a temperature signal from a temperature sensor disposed on the liquid crystal panel.

Further, in the above-described first to fourth embodiments, the case where the temperature control circuits 23, 53, 63 and 73 are arranged outside the liquid crystal panels 16 to 18 has been described as an example. , 53, 63, 73, like the liquid crystal drive circuits 34a to 34c,
18 and can be arranged integrally. In the above-described first to fourth embodiments, the case where analog temperature signals output from the temperature sensors 16A to 18A are digitally converted by the A / D converter and then input to the CPU has been described as an example. If a temperature sensor that outputs a digital signal is used instead of a temperature sensor that outputs an analog signal, a temperature signal from the temperature sensor can be directly input to the CPU.

Further, in the above-described first to fourth embodiments, CPUs are provided in the temperature control circuits 23, 53, 63, and 73, and the temperature is controlled by the CPU. However, instead of the CPU, an analog amplifier using an operational amplifier or the like is used. An arithmetic circuit may be provided in the temperature control circuit so that the analog arithmetic circuit performs the same temperature control. Further, in the above-described first to fourth embodiments, a case where a liquid crystal panel is used as a spatial light modulator and the present invention is applied to a liquid crystal panel has been described as an example.
Even when a device (DMD) is used and a temperature sensor or the like is embedded in the digital micromirror device, the same effect as the present invention can be obtained.

[0092]

As described above, according to the first and second aspects of the present invention, the temperature rise of the spatial light modulator can be accurately detected by the built-in temperature sensor.
Temperature control according to a temperature change of the spatial light modulator can be performed with good responsiveness. According to the third aspect of the present invention, since the voltage corresponding to the video signal supplied to the spatial light modulator is corrected in accordance with the actual temperature change of the spatial light modulator, a stable projection image is always obtained. As a result, the projection capability of the liquid crystal projector can be improved.

Further, according to the inventions described in claims 4 and 5, an abnormal rise in the temperature of the liquid crystal panel can be prevented beforehand, so that the liquid crystal panel is destroyed, the performance of the liquid crystal panel itself is reduced, and the temperature of the liquid crystal panel itself is reduced. Life extension can be prevented. According to the invention described in claims 6 to 8, since the temperature of the spatial light modulator is adjusted based on the temperature of the spatial light modulator detected by the temperature detecting means, the actual spatial light modulator itself is adjusted. By controlling the temperature according to the temperature, stable operation under a constant temperature condition is guaranteed.

Further, according to the ninth aspect of the present invention, since the cooling / heating of the liquid crystal panel is performed by the electronic cooling / heating element closely attached to the liquid crystal panel, the temperature control of the liquid crystal panel is simplified and the response is improved. Stable operation is always guaranteed under constant temperature conditions.

Further, according to the tenth aspect of the present invention, it is possible to adjust the temperature according to the temperature change by the electronic cooling and heating element without hindering the operation of modulating linearly polarized light by the reflective liquid crystal panel. Furthermore, according to the eleventh aspect, it is possible to adjust the temperature according to the temperature change by the electronic cooling and heating element without hindering the linearly polarized light modulation operation by the transmission type liquid crystal panel.

According to the twelfth aspect of the invention, the liquid crystal panel can be cooled / heated only by changing the magnitude and direction of the current flowing through the Peltier element, and the liquid crystal panel can be stably operated under a constant temperature condition. Can work. Further, according to the present invention, it is possible to individually perform high-precision temperature control according to the temperature change of each liquid crystal panel, so that a projection image is always obtained under a stable temperature condition for each color. be able to.

[Brief description of the drawings]

FIG. 1 shows a liquid crystal projector 10 according to a first embodiment.
FIG. 3 is a diagram showing the configuration of FIG.

FIG. 2 is a diagram showing a specific configuration of a liquid crystal panel 16;

FIG. 3 is a diagram showing an internal configuration of a temperature control circuit 23;

FIG. 4 is a liquid crystal projector 50 according to a second embodiment.
FIG. 3 is a diagram showing the configuration of FIG.

FIG. 5 is a diagram showing an internal configuration of a temperature control circuit 53;

FIG. 6 shows a liquid crystal projector 60 according to a third embodiment.
FIG. 3 is a diagram showing the configuration of FIG.

FIG. 7 is a diagram illustrating an internal configuration of a temperature control circuit 63;

FIG. 8 shows a liquid crystal projector 70 according to a fourth embodiment.
FIG. 3 is a diagram showing the configuration of FIG.

FIG. 9 is a diagram showing an internal configuration of a temperature control circuit 73;

FIG. 10 is a diagram showing a configuration of a transmissive liquid crystal panel 80.

FIG. 11 is a diagram showing a configuration of a conventional liquid crystal projector 110.

[Explanation of symbols]

10, 50, 60, 70, 110 Liquid crystal projector 16, 17, 18, 116, 117, 118 Liquid crystal panel 16A, 17A, 18A, 81 Temperature sensor 16B, 17B, 18B, 82 Peltier unit 16C, 17C, 18C Liquid crystal 23, 53, 63, 73 Temperature control circuit 34a, 34b, 34c Liquid crystal drive circuit 21, 121, 122 Cooling fan 80 Transmissive liquid crystal panel 31 Translucent substrate 33, 83 Base unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 5/74 H04N 5/74 B

Claims (13)

[Claims] 1. A spatial light modulator for modulating incident light in accordance with an externally supplied video signal, wherein the spatial light modulator includes a temperature sensor. 2. The spatial light modulator according to claim 1, wherein the spatial light modulator is a liquid crystal panel, and the liquid crystal panel converts a polarization state of the incident linearly polarized light into a video signal given from the outside. A spatial light modulation device, which modulates light in accordance with the modulated light to emit modulated light. 3. A liquid crystal projector using the spatial light modulator according to claim 2, wherein a voltage corresponding to the video signal is supplied to the liquid crystal panel, and the liquid crystal panel adjusts to a temperature detected by the temperature sensor. A liquid crystal projector comprising a voltage correction unit for correcting a voltage corresponding to the video signal based on the voltage. 4. A liquid crystal projector using the spatial light modulator according to claim 2, wherein the light source means for generating the linearly polarized light, and a temperature detected by the temperature sensor is out of a predetermined range. And a control means for stopping the operation of the light source means. 5. A liquid crystal projector using the spatial light modulation device according to claim 2, wherein, when the temperature detected by the temperature sensor is out of a predetermined range, a notifying means for notifying the outside to the outside. A liquid crystal projector comprising: 6. A spatial light modulator that modulates incident light in accordance with an externally supplied video signal, wherein the temperature detector detects a temperature of the spatial light modulator, and the temperature is detected by the temperature detector. Based on temperature
A spatial light modulator comprising: a temperature adjuster for adjusting a temperature of the spatial light modulator. 7. The spatial light modulator according to claim 6, wherein the spatial light modulator is a liquid crystal panel, and the liquid crystal panel converts a polarization state of the incident linearly polarized light into a video signal given from the outside. A spatial light modulation device, which modulates light in accordance with the modulated light to emit modulated light. 8. The spatial light modulator according to claim 7, wherein said temperature detecting means is a temperature sensor built in a base portion of said liquid crystal panel. 9. The spatial light modulator according to claim 7, wherein said temperature adjusting means includes an electronic cooling / heating element closely attached to a base portion of said liquid crystal panel. Light modulation element. 10. The spatial light modulator according to claim 9, wherein the liquid crystal panel is a reflection type liquid crystal panel that emits the modulated light from the plane of incidence of the linearly polarized light; A spatial light modulation device, which is disposed in close contact with a surface of the liquid crystal panel opposite to the incident surface. 11. The spatial light modulator according to claim 9, wherein the liquid crystal panel is a transmissive liquid crystal panel in which a plane of incidence of the linearly polarized light and a plane of emission of the modulated light face each other. The spatial light modulator, wherein the cooling and heating element is disposed in close contact with a surface of the liquid crystal panel other than the entrance surface and the exit surface. 12. The spatial light modulator according to claim 9, wherein the thermoelectric cooler / heater is a Peltier device. 13. A liquid crystal projector using the spatial light modulator according to claim 9, wherein the liquid crystal projector has at least one liquid crystal panel. The at least one liquid crystal panel has the built-in temperature sensor and the electronic cooling / heating element disposed in close contact with the liquid crystal panel, and the temperature adjustment unit responds based on the temperature detected by the individual temperature sensor. A liquid crystal projector characterized in that the electronic cooling and heating elements are individually driven to individually adjust the temperature of the liquid crystal panel.