JP2005128349A - Liquid crystal panel and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal panel and a projector which have high reliability and aim at cost reduction by reducing the number of positions for assembling and adjusting. <P>SOLUTION: The projector 1 is equipped with an LED array 2 which emits three color light rays of red, green, blue 2r, 2g, 2b, the liquid crystal panel 3A which has liquid crystal spacial light modulators 30R, 30G, 30B modulating the three color light rays 2r, 2g, 2b emitted from the LED array 2 with image signals corresponding to the respective colors and outputting three color image light rays of red, green, blue 3r, 3g, 3b, reflection prisms 4R, 4G respectively reflecting the red image light ray 3r and the green image light ray 3g, a synthesis prism 5 synthesizing three color image light rays 3r, 3g, 3b, and a projection lens 6 enlarging and projecting a color image light ray 5a obtained by the synthesis with the synthesis prism 5 on a screen 7. The respective liquid crystal spacial light modulators 30R, 30G, 30B of the liquid crystal panel 3A are preliminarily aligned and attached to a common frame body 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal panel having three liquid crystal spatial light modulators and a projector using the same, and more particularly, to a liquid crystal panel and a projector that are highly reliable and reduce costs by reducing the number of assembly and adjustment points. .

  Projectors using liquid crystal spatial light modulators are being used as large-screen TVs and discussion / presentation displays as devices that can realize large-screen displays at low prices (for example, Patent Document 1, Patent Document 2, Patents). Reference 3 and Patent Document 4).

  FIG. 6 shows a conventional projector described in Patent Document 1. The projector 1 includes a white light source 10 that emits parallel white light 10a, a dichroic separation prism 11 that separates the white light 10a emitted from the white light source 10 into red light 2r, green light 2g, and blue light 2b; Reflective mirrors 13R and 14R that allow light 2r to enter the liquid crystal spatial light modulator 30R, reflective mirrors 13G and 14G that allow green light 2g to enter the liquid crystal spatial light modulator 30G, red light 2r, green light 2g, and blue light 2b Liquid crystal spatial light modulators 30R, 30G, and 30B that modulate the image light with image signals corresponding to the respective colors, and red image light 3r, green image light 3g, and blue image light modulated by the liquid crystal spatial light modulators 30R, 30G, and 30B. A combining prism 5 for combining 3b, and a projection lens 6 for enlarging and projecting the color image light 5a obtained by combining the combining prism 5 on the screen 7. Provided.

Each of the liquid crystal spatial light modulators 30R, 30G, and 30B has the same optical distance to the projection lens 6 so that the image projected on the screen 7 is not blurred, and each position is the object of the projection lens 6. It arrange | positions around the synthetic | combination prism 5 so that it may become a point. In this case, since the size of one pixel in each of the liquid crystal spatial light modulators 30R, 30G, and 30B is 20 to 30 μm, each of the liquid crystal spatial light modulators 30R, 30G, and 30B has a position of each pixel with an accuracy of about 1 μm. Aligning. With such a configuration, the color image light 5a is enlarged and projected on the screen 7, and a large screen color image with little blur can be enjoyed at home or the like.
JP 62-125791 A (FIG. 7) JP 2000-292663 A (FIG. 1) JP 2000-298309 A (FIG. 1) Japanese Patent Laid-Open No. 2002-40389 (FIG. 1)

  However, according to the conventional projector, each of the liquid crystal spatial light modulators 30R, 30G, and 30B is three-dimensionally aligned with the combining prism 5 with high accuracy, so that a large-scale assembly device is required. It takes time to. Further, after separating the white light 10a emitted from the white light source 10 into red, green, and blue parallel lights, a plurality of reflecting mirrors are required to make them incident on the liquid crystal spatial light modulators 30R, 30G, and 30B. Therefore, a great amount of man-hours are required for the highly accurate position / angle adjustment. Therefore, this is a major factor that makes it difficult to reduce the cost of the projector.

  Accordingly, it is an object of the present invention to provide a liquid crystal panel and a projector that are highly reliable and cost-effective by reducing the number of assembly adjustment points.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a liquid crystal panel having three liquid crystal spatial light modulators for modulating three color lights of red, green and blue with image signals corresponding to the respective colors. The light modulator provides a liquid crystal panel that is arranged on the same plane.

  In order to achieve the above object, the second invention provides a light source that emits light of three colors of red, green, and blue, three liquid crystal spatial light modulators that modulate the three-color light with an image signal corresponding to each color, A synthesis optical system for synthesizing the three color lights modulated by three liquid crystal spatial light modulators, and a projection lens for enlarging and projecting color image light obtained by the synthesis of the synthesis optical system on a screen. The liquid crystal spatial light modulator provides a projector characterized by being arranged on the same plane.

  According to the first and second aspects of the invention, the number of assembling steps can be greatly reduced by arranging the three liquid crystal spatial light modulators for modulating three-color light on the same plane.

  According to the present invention, since the three liquid crystal spatial light modulators are arranged on the same plane, the positions of the three liquid crystal spatial light modulators can be easily adjusted. Thus, the reliability is high and the cost can be reduced.

  FIG. 1 shows a main part of a projector according to a first embodiment of the invention. As shown in FIG. 1A, the projector 1 includes an LED array 2 that emits three colors of parallel red light 2r, green light 2g, and blue light 2b, and three-color light emitted from the LED array 2 for each color. A liquid crystal panel 3A having liquid crystal spatial light modulators 30R, 30G, and 30B that output three-color image light of red image light 3r, green image light 3g, and blue image light 3b after being modulated with an image signal corresponding to A reflecting prism 4R that reflects the light 3r, a reflecting prism 4G that reflects the green image light 3g, a combining prism 5 that combines the three-color image light of the red image light 3r, the green image light 3g, and the blue image light 3b; And a projection lens 6 for enlarging and projecting color image light 5a obtained by combining the prisms 5 onto a screen 7.

  As shown in FIG. 1A, the LED array 2 includes a plurality of red LEDs 20R, green LEDs 20G, and blue LEDs 20B that are two-dimensionally arranged. The LED array 2 includes a substrate 21, a plurality of cup-shaped recesses 21a formed two-dimensionally on the surface of the substrate 21, as shown in FIG. A plurality of LEDs 20R, 20G, and 20B disposed on the bottom surface of the recess 21a, and a plurality of resins that seal the recesses 21a and the LEDs 20R, 20G, and 20B, and shape the emitted light of the LEDs 20R, 20G, and 20B into substantially parallel light A mold lens 22. A microlens array or the like may be used instead of the plurality of resin mold lenses 22.

  In each of the liquid crystal spatial light modulators 30R, 30G, and 30B of the liquid crystal panel 3A, a plurality of pixels are arranged in a matrix and attached in advance to a frame 8 as a common holding body.

  The red reflecting prism 4R is formed by forming an interference film (dichroic film) that reflects the red light 2r on the hypotenuse of a right-angle prism and combining them. The green reflecting prism 4G is formed by forming an interference film reflecting the green light 2g on the hypotenuse of a right-angle prism and combining them.

  The combining prism 5 reflects the red light 2r on the two sides sandwiching the right angle of the right-angle prism, and transmits an interference film that transmits the other color light and an interference film that reflects the green light 2g and transmits the other color light. Are combined and four of them are combined.

  The red reflecting prism 4R, the green reflecting prism 4G, and the combining prism 5 are joined to each other by an optical adhesive and arranged on the same plane.

  Next, the operation of the projector 1 according to the first embodiment configured as described above will be described. When parallel red light 2r, green light 2g, and blue light 2b are emitted from the red LED 20R, green LED 20G, and blue LED 20B of the LED array 2, the liquid crystal spatial light modulators 30R, 30G, and 30B of the liquid crystal panel 3A are emitted from the LED array 2. The emitted red light 2r, green light 2g, and blue light 2b are modulated with an image signal corresponding to each color. The red image light 3r modulated by the red liquid crystal spatial light modulator 30R is reflected by the reflecting prism 4R and incident on the combining prism 5, and the green image light 3g modulated by the green liquid crystal spatial light modulator 30G. Is reflected by the reflecting prism 4G and enters the combining prism 5, and the blue image light 3b modulated by the blue liquid crystal spatial light modulator 30B enters the combining prism 5 as it is. The combining prism 5 combines the red image light 3r, the green image light 3g, and the blue image light 3b, and the projection lens 6 enlarges and projects the color image light 5a obtained by combining the combining prism 4 onto the screen 7.

  According to the first embodiment, since the three liquid crystal spatial light modulators 30R, 30G, and 30B are arranged on the same plane, highly accurate alignment is performed by a relatively simple assembly device (not shown). Can be performed. Further, since the two reflecting prisms 4R and 4G and the combining prism 5 are joined so as to have the same surface by an optical adhesive, position adjustment is not necessary. As described above, the one-dimensional assembly of the prisms 4R and 4G and the liquid crystal spatial light modulators 30R, 30G, and 30B enables the position and angle of the red, blue, and green modulated light to be adjusted. Compared to the number of assembly adjustment points, the number of assembling steps can be greatly reduced. Thereby, a projector with high reliability and low cost can be provided.

  2A and 2B show a liquid crystal panel according to a second embodiment of the present invention. FIG. 2A is a plan view, and FIG. As shown in FIG. 2B, the liquid crystal panel 3B includes a rear transparent substrate 31A made of glass, sapphire or the like having a common electrode 32A, a signal line 33, a scanning line, a TFT (Thin Film Transistor) 34, an insulating film. 35, between the pixel electrode 32B, the front transparent substrate 31B made of glass, sapphire or the like having the signal line drive circuits 37R, 37G, 37B and the scanning line drive circuits 38R, 38G, 38B shown in FIG. It has a structure in which a liquid crystal layer 36 made of polymer dispersed liquid crystal or the like is sandwiched, and these are formed by a thin film process. The pixel electrodes 32B are arranged in a matrix on the front transparent substrate 31B, and the liquid crystal spatial light modulators 39R, 39G, and the like, which are formed of pixels formed in a matrix on the liquid crystal layer 36 corresponding to the pixel electrodes 32B. The liquid crystal spatial light modulators 30R, 30G, and 30B are configured by 39B, the signal line drive circuits 37R, 37G, and 37B that drive the liquid crystal spatial light modulators 39R, 39G, and 39B and the scanning line drive circuits 38R, 38G, and 38B. Yes. The gate of the TFT 34 is connected to the scanning line, the drain is connected to the signal line 33, and the source is connected to the pixel electrode 32B. The signal line driving circuit 37 applies an image signal to the drain of the TFT 34 via the signal line 33 group, and the scanning line driving circuit 38 applies a gate pulse to the gate of the TFT 34 via the scanning line group in time series. is there.

  According to the second embodiment, since the relative position of the pixel of the liquid crystal layer 36 is determined by the accuracy of the mask aligner in the thin film process, it can be set with an accuracy of 1 μm or less. At present, the production yield of the liquid crystal spatial light modulators 39R, 39G, and 39B exceeds 90%. Therefore, even if they are integrated in this way, the yield is not significantly reduced and the cost is reduced. Can do. In addition, when the three liquid crystal spatial light modulators 30R, 30G, and 30B are arranged on the same plane in this way, the intervals between the parallel lights of the red light 2r, the green light 2g, and the green light 2b that have passed through them are Since it is preset and cannot be adjusted depending on the arrangement of the modulators 30R, 30G, and 30B, it is necessary to manufacture the reflecting prisms 4R and 4G and the combining prism 5 with high accuracy. With the current prism manufacturing technique, mass production is possible with an angle of the reflecting surface within 10 minutes and a length accuracy of 1 μm or less, and the manufacturing accuracy required in this embodiment can be sufficiently satisfied. Also, if the production accuracy happens to be insufficient, the angles of the incident light 2r, 2g, 2b can be adjusted by adjusting the rear reflecting prisms 4R, 4G. In the present embodiment, the optical distances from the three liquid crystal spatial light modulators 30R, 30G, 30B to the projection lens 6 are different by the reflecting prisms 4R, 4G, and the optical paths of the red light 2r and the green light 2g are different. The length of the diffraction is slightly different between the red image light 3r, the green image light 3g, and the blue image light 3b. However, the red, green, and blue three-color lights are shaped into parallel lights with high accuracy, respectively. Image blur is negligible.

  FIG. 3 shows a projector according to a third embodiment of the present invention. The projector 1 according to the third embodiment has a refractive index (reflective) so that the optical distances from the three liquid crystal spatial light modulators 30R, 30G, and 30B to the projection lens 6 are equal in the first embodiment. A glass spacer 9A as a translucent member having a refractive index higher than that of the prisms 4R and 4G and a thickness is disposed between the blue liquid crystal spatial light modulator 30B and the combining prism 5. . According to the third embodiment, since the optical distances from the three liquid crystal spatial light modulators 30R, 30G, and 30B to the projection lens 6 can be matched, image blur due to different optical distances of the respective colors. Can be prevented.

  FIG. 4 shows a projector according to a fourth embodiment of the invention. The projector 1 according to the fourth embodiment has a green color so that the positions of the three liquid crystal spatial light modulators 30R, 30G, and 30B are the object points of the projection lens 6 in the first embodiment. A relay lens 9B is inserted between the liquid crystal spatial light modulator 30G for use and the combining prism 5. According to the fourth embodiment, since the three liquid crystal spatial light modulators 30R, 30G, and 30B can be aligned with the object point position of the projection lens 6, blurring of the image can be prevented.

  FIG. 5 shows a projector according to a fifth embodiment of the invention. The projector 1 according to the fifth embodiment is different from the first embodiment on the light source side, and a white light source 10 that emits parallel white light 10 a and a white light emitted from the white light source 10. The dichroic separation prism 11 that separates the light 10a into red light 2r, green light 2g, and blue light 2b and enters the blue light 2b into the blue liquid crystal spatial light modulator 30B, and the red light 2r into the liquid crystal spatial light for red A reflecting prism 12R that enters the modulator 30R and a reflecting prism 12G that enters the green light 2g into the green liquid crystal spatial light modulator 30G are provided.

  The dichroic separation prism 11 reflects the red light 2r on two sides sandwiching the right angle of the right-angle prism, reflects the interference film that transmits the other color light, and reflects the green light 2g, and the interference that transmits the other color light. A film is formed, and four of them are combined.

  The reflecting prism 12R is formed by forming an interference film that reflects the red light 2r on the hypotenuse of a right-angle prism and combining them. The reflecting prism 12G is formed by forming an interference film that reflects the green light 2g on the hypotenuse of a right-angle prism and combining them.

  The dichroic separating prism 11 and the reflecting prisms 12R and 12G are joined so as to have the same surface by an optical adhesive.

  According to the fifth embodiment, since the dichroic separation prism 11 and the reflecting prisms 12R and 12G for separating the output light of the white light source 10 into red, blue and green are integrated, the white light source 10 and the projection lens are integrated. All the optical systems except 6 can be integrated, and it is possible to provide a projector with higher reliability and lower assembly cost.

  In each of the above embodiments, the LED array is used as the light source. However, a surface emitting semiconductor laser or an edge emitting semiconductor laser may be used. As a result, the electrical efficiency of the light source can be increased and the power used can be reduced. In this case, the light source and the liquid crystal spatial light modulator may be integrated. As a result, the number of parts required for assembly and adjustment can be reduced, and a highly reliable projector can be provided.

  In each of the above embodiments, the transmissive liquid crystal spatial light modulator has been described. However, the present invention can also be applied to a reflective liquid crystal spatial light modulator as in the transmissive type.

  Alternatively, a reflecting mirror may be used instead of the reflecting prism, and a dichroic mirror arranged in an X shape may be used instead of the combining prism. As a result, the assembly adjustment of the mirror is required, but the assembly adjustment of the three liquid crystal spatial light modulators can be reduced and the component cost can be reduced.

(A) is a figure which shows the principal part of the projector which concerns on the 1st Embodiment of this invention, (b) is principal part sectional drawing of an LED array. (A) is a top view of the liquid crystal panel which concerns on the 2nd Embodiment of this invention, (b) is the principal part sectional drawing. It is a figure which shows the projector which concerns on the 3rd Embodiment of this invention. It is a figure which shows the projector which concerns on the 4th Embodiment of this invention. It is a figure which shows the projector which concerns on the 5th Embodiment of this invention. It is a figure which shows the conventional projector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projector 2 LED array 2b Blue light 2g Green light 2r Red light 3A, 3B Liquid crystal panel 3b Blue image light 3g Green image light 3r Red image light 4R, 4G Reflective prism 5 Synthetic prism 5a Color image light 6 Projection lens 7 Screen 8 Frame Body 9A Glass spacer 9B Relay lens 10 White light source 10a White light 11 Dichroic separation prisms 12R, 12G Reflective prisms 13R, 13G, 14R, 14G Reflective mirror 20R Red LED
20G green LED
20B Blue LED
21 Substrate 21a Recess 22 Resin mold lens 30R, 30G, 30B Liquid crystal spatial light modulator 31A Rear transparent substrate 31B Front transparent substrate 32A Common electrode 32B Pixel electrode 33 Signal line 34 TFT
35 Insulating film 36 Liquid crystal layer 37R, 37G, 37B Signal line drive circuit 38R, 38G, 38B Scan line drive circuit 39R, 39G, 39B Liquid crystal spatial light modulator

Claims (9)

In a liquid crystal panel having three liquid crystal spatial light modulators for modulating red, green, and blue light with image signals corresponding to the respective colors,
The liquid crystal panel, wherein the three liquid crystal spatial light modulators are arranged on the same plane.   The liquid crystal panel according to claim 1, wherein the three liquid crystal spatial light modulators are held by a common holder.   The liquid crystal panel according to claim 1, wherein the three liquid crystal spatial light modulators are formed on a common transparent substrate. A light source that emits red, green, and blue light;
Three liquid crystal spatial light modulators for modulating the three-color light with an image signal corresponding to each color;
A combining optical system for combining the three color lights modulated by the three liquid crystal spatial light modulators;
A projection lens for enlarging and projecting color image light obtained by the synthesis of the synthesis optical system on a screen,
The projector according to claim 3, wherein the three liquid crystal spatial light modulators are arranged on the same plane.   The three liquid crystal spatial light modulators include at least one liquid crystal spatial light modulator and the projection lens, each of which has a refractive index and a thickness that are set so that an optical distance to the projection lens is equal. The projector according to claim 4, wherein the projector is disposed between the two.   In the three liquid crystal spatial light modulators, a relay lens is disposed between at least one of the liquid crystal spatial light modulator and the projection lens so that each position is an object point of the projection lens. The projector according to claim 4.   The combining optical system includes two reflecting prisms that respectively reflect two-color light of the three-color light, and a combining prism that combines the remaining one-color light of the three-color light and the two-color light. The projector according to claim 4, wherein the prism and the combining prism are arranged on the same plane.   The light source includes: a white light source that emits white light; a separation prism that separates white light into the three-color light; and two reflection prisms that respectively reflect two-color light reflected by the separation prism among the three-color light. The projector according to claim 4, wherein the separating prism and the two reflecting prisms are arranged on the same plane. The light source includes a light source array having a plurality of light emitting diodes or semiconductor lasers that emit the three-color light, and a shaping optical system that shapes the three-color light emitted from the light source array into parallel light. The projector according to claim 4.