KR0115475Y1 - Transmissive / Reflective Liquid Crystal Projector - Google Patents

Abstract

The present invention relates to a transmissive / reflective type liquid crystal projector. In the conventional optical system, the transmissive optical system using PDLC increases the aperture size of the projection lens, which is a basic condition for increasing the brightness, and the scattered light in the case of black As the intensity of light reaching the screen increases, the contrast ratio drops.

In addition, when two apertures are used, one aperture size can be reduced, and contrast can be increased. However, when focusing light with other apertures, there is an amount of light blocked by the aperture stop. The resolution of the projection lens is reduced by the field lens existing between the liquid crystal panel and the projection lens.

In particular, when high image quality (HD) is required, since resolution is very important, it is difficult to use it as a high definition optical system, or there are many limitation factors when designing a field lens and a projection lens simultaneously.

On the other hand, the reflective optical system is easy to apply to twisted nematic, but PDLC has a disadvantage in that it cannot take advantage of the polarizing beam splitting means (PBS).

In order to solve this problem, the present invention uses a filter (SF) that passes light incident at a specific angle to maintain brightness and increase contrast in a transmission optical system, and to reflect light incident at a specific angle in a reflection optical system. It is an object of the present invention to provide a liquid crystal projector which increases brightness and contrast by using a filter (SF),? / 4 plate means, and PBS to pass.

Description

Transmissive / Reflective Liquid Crystal Projector

1 is an operation principle diagram of a conventional PDLC optical system.

2 is a block diagram of a conventional transmission optical system using PDLC.

3 is another configuration diagram of a conventional transmission optical system.

4 is a variation of the acceptance angle Θφ of the projection lens according to the size of the aperture stop in FIG.

5 is a structural diagram of a conventional reflective optical system.

6 is another structural diagram of a conventional reflective optical system.

7 is a block diagram of a transmissive liquid crystal projector of the present invention.

8 is another configuration of the present invention transmissive liquid crystal projector.

9 is a specific view of SF according to the present invention, (a) is the installation position of the SF, (b) is a transmission light intensity distribution diagram by SF.

10 is a block diagram of a reflective liquid crystal projector of the present invention.

11 is another configuration of the present invention reflective liquid crystal projector.

12 is a characteristic diagram of [lambda] / 4 plate with respect to FIG. 10 and FIG.

* Explanation of symbols for main parts of the drawings

100: light source 101: reflector

102,121: condenser lens 103,108,123-1,129: liquid crystal panel

104, 110, 125: SF means 105, 111, 126: projection lens

106,127: screen 107: color separation mirror

109 color synthesis mirror 122 polarization beam separation means

123: color sorting unit 123-2,123-3: color sorting filter

124: lambda / 4 plate 128: color discriminating prism

130: control unit DM1-DM3: color separation mirror

DM4-DM6: Color Synthesis Mirror

The present invention relates to a projector optical system using a polymer molecular liquid crystal panel (hereinafter referred to as PDLC), and in particular, a transmission / reflection to improve the contrast and the brightness of a transmission optical system and the reflection optical crab. It relates to a type liquid crystal projector.

Generally, PDLC is used in a conventional optical system, and the operation principle of the PDLC is as follows.

First, as shown in (a) of FIG. 1, when the electric field is turned off, the refractive index of the polymer molecule 1 and the refractive index of the liquid crystal molecule 2 are different from each other, so that the traveling path is different as the light proceeds.

That is, a phenomenon occurs in which light is scattered between the polymer molecules 1 and the liquid crystal molecules 2.

However, as shown in (b) of FIG. 1, when the electric field is applied, the refractive index of the polymer molecules 1 forming the PDLC is the same as the refractive index of the liquid crystal molecules 2, and thus the light incident perpendicularly to the PDLC panel plane is applied. Is transmitted without being scattered at all.

That is, the PDLC appears transparent when the electric field is applied.

2 is a basic block diagram of a conventional transmission optical system using a PDLC, and as shown therein, a light source 10 emitting white spectral distribution and a light emitted from the light source 10 are irradiated to the PDLC 12. A reflector 11, an aperture stop 13 for blocking light scattered by the PDLC 12 when the electric field is off, and a projection lens 14 for projecting an image formed on the PDLC 12 on a screen. .

In the conventional transmission optical system configured as described above, the image formed in the PDLC 12 is blocked or transmitted at the aperture stop 13 according to the electric field applied state and displayed on the screen. That is, when the light source 10 emits white light, the reflector 11 irradiates the light to the PDLC 12 to form an image.

At this time, when the electric field is applied as shown in FIG. 2A, the image formed by the PDLC 12 passes through the aperture stop 13, which is enlarged by the projection lens 14 and displayed on the screen. It is done.

On the other hand, when the electric field is turned off as shown in (b) of FIG. 2, the image formed on the PDLC 12 is blocked by the aperture stop 13, so that no image is displayed on the screen.

3 is another structural diagram of a conventional optical system, and is an optical system that improves contrast by using two apertures 12-1 and 12-2.

That is, when the aperture sizes D1 and D2 are made smaller (Fig. 4 (b)) as in Fig. 4, the acceptance angle φ of the projection lens 14 becomes smaller, so that when the electric field is off, When the light is scattered, the black level on the screen 15 becomes even lower.

In addition, the contrast of the liquid crystal projector can be defined as a contrast ratio, which is a value obtained by dividing the intensity of light in a white signal by the intensity of light in a black signal. The smaller the size (D1, D2), the higher the contrast ratio.

On the other hand, Figure 5 is a structural diagram of a conventional reflective optical system, as shown in the condensing lens 22 for condensing the light emitted from the light source 21 to make parallel light, parallel light through the condensing lens 22 Polarizing beam separation means 23 for transmitting and reflecting the light, and red (R), green (G), and blue (B) are selected from the polarization beams projected by the polarization beam separation means (23). A color screening unit 24 for transmitting and reflecting the light beam from the liquid crystal panel 24-1 and inverting the light beam from the liquid crystal panel 24-1 to be incident on the polarizing beam separating means 23; And a projection lens 25 for projecting the polarized beam reflected by the means 23 onto the screen 26 in an enlarged manner. (B) is a first color filter 24-2 reflecting the blue liquid crystal panel 24-1B and transmitting red (R) and green (G), and the first color. The second screening filter (24-3) reflects green (G) through the sorting filter (24-2) to the green liquid crystal panel (24-1G) and red (R) passes through the red liquid crystal panel (24-1R). ).

In the conventional reflective optical system configured as described above, the light emitted from the light source 21 is collected by the condenser lens 22 and then becomes parallel light, and is incident on the polarizing beam separation means 23.

The incident light is passed through the polarization beam separation means 23 and reflected by the blue liquid crystal panel 24-1B through the first color filter 24-2 of the color screen 24. And red (R) and green (G) are incident on the second color filter 24-3, and green (G) incident on the second color filter 24-3 is the green liquid crystal panel 24-. 1G) and the red color R is transmitted through the red liquid crystal panel 24-1R.

In this way, the color signals applied to the red, green, and blue liquid crystal panels 24-1R, 24-1G, and 24-1B, respectively, are reflected back to the second and first color separation filters 24-3 and 24-2. The incident light is incident on the polarization beam separating means 23 through the light beam, and the incident light is reflected by the projection lens 25 and enlarged and projected onto the screen 26 by the projection lens 25.

6 is another structural diagram of a conventional reflective optical system. As shown in FIG. 6, the reflector 32 condenses the light emitted from the light source 31 to form parallel light, and the beam reflected from the reflector 32. Red (R), green (G), and blue (B) are selected from the polarizing beam splitter 33 for transmitting and reflecting, and the polarizing beam reflected by the polarizing beam splitting means 33 to control the control unit 36. Color-split prism 34 and the polarization beam which transmit and reflect to each liquid crystal panel 35 under control and inversely process the beam reflected from the liquid crystal panel 35 to be incident on the polarization beam separation means 33. And a projection lens 37 for projecting the polarized beam reflected by the separating means 33 onto the screen 38 in an enlarged manner.

In the conventional reflective optical system configured as described above, when light is emitted from the light source 31, the light is collected by the reflector 32 and then incident on the polarizing beam separation means 33 as parallel light.

The incident light is reflected by the polarization beam splitter 33 and is incident on the color discriminating prism 34, and the incident light is selected as red (R), green (G), and blue (B), and the control unit ( Each of the liquid crystal panels 35R, 35G, 35B under the control of 36 is projected.

The projected light is reflected by the liquid crystal panels 35R, 35G and 35B again and is incident on the projection lens 37 through the color discriminating prism 34 and the polarizing beam separating means 33.

Accordingly, the projection lens 37 displays the image by expanding and projecting the incident light onto the screen 38.

However, in the conventional optical system described above, in the transmission type optical system using PDLC, the influence of contrast and brightness determined by the size of the aperture stop is in a tread off relationship with each other.

In FIG. 2, which is the basic transmission optical system of PDLC, as the aperture size of the projection lens, which is a basic condition for increasing brightness, increases, the intensity of scattered light reaching the screen through the projection lens is increased so that the contrast ratio decreases. do.

On the other hand, the transmissive optical system as shown in FIG. 3 can reduce the size of the aperture 12-2, so that the contrast can be increased. However, when the light is focused by the aperture 12-1, the light of the light blocked by the aperture stop is reduced. The amount is present and thus the brightness is expected to be reduced, and the resolution of the projection lens is reduced by the field lens existing between the liquid crystal panel and the projection lens.

In particular, when high image quality (HD) is required, resolution is very important, and thus it is difficult to use a high definition optical system or there are many limitations when designing a field lens and a projection lens simultaneously.

On the other hand, the reflective optical system is easy to apply to twisted nematic, but PDLC has a disadvantage in that it cannot take advantage of the polarization beam separation means (PBS).

That is, in the case of twisted nematic, when the light separated by the polarization beam separation means comes out through the reflection type (LCD), the polarization direction is returned by 90 °, but in the case of PDLC, there is no way to change the polarization direction. Therefore, since there is not enough ground to use the polarizing beam separating means, a half mirror is used instead of the polarizing beam separating means, but when the half mirror is used, the amount of light incident on the projection lens is reduced by half.

In order to solve this problem, the present invention uses a small beam angle transmission filter (hereinafter referred to as SF) to pass light incident at a specific angle to maintain brightness and increase contrast in a transmission optical system. In the reflective optical system, an object of the present invention is to provide a liquid crystal projector that increases brightness and contrast.

In order to achieve the above object, the present invention provides a transmissive liquid crystal projector with light source means for emitting white spectrum light, reflecting means for inducing a path of light emitted from the light source means, and light guided by the reflecting means. A light converging means for condensing and converting light into parallel light, a liquid crystal panel which receives an electric signal from an electric signal supply unit inside the projector, and changes the scattering degree of light, and when the electric signal is black, some angle of light scattered from the liquid crystal panel A specific beam transmission means for transmitting only the light inside and reflecting more light, and projection lens means for expanding and projecting an image through the specific beam transmission means on a screen, wherein the specific beam transmission means comprises a liquid crystal panel and a projection lens means. Configured to be located in between.

In addition, the present invention to achieve the above object, the transmissive liquid crystal projector is a light source means for emitting light of the white spectrum, the reflection means for inducing the path of the light emitted from the light source means, and the reflection means Color separation means for separating white light into wavelength bands of red, green, blue, and three regions, and red, green, and blue light modulated by electric signals for each light separated by red, green, and blue from the color separation means. Three liquid crystal panels, color synthesizing means for synthesizing the light formed on the three liquid crystal panels, and only the light within a part of the angle (Δθ) of the light synthesized and scattered by the color synthesizing means transmits and reflects more light A specific beam transmitting means, and projection lens means for expanding and projecting an image through the specific beam transmitting means onto a screen.

On the other hand, in order to achieve the above object, the present invention, a condenser lens means for condensing the light emitted from the light source means into a parallel light, and a polarizing beam for transmitting and reflecting parallel light through the condenser lens means Red (R), green (G) and blue (B) are separated from the separating means and the polarizing beam projected by the polarizing beam separating means, and transmitted and reflected to each liquid crystal panel, and the beam reflected from the liquid crystal panel is A color discrimination means for inversely processing and incident on the polarization beam separation means, a? / 4 plate means positioned for each liquid crystal panel of the color discrimination means to impart a polarization function to the liquid crystal panel, and the polarization beam separation means Specific beam transmission means for transmitting only the light within a certain angle (Δθ) of the reflected polarization beam and reflecting more light, and to enlarge and project the image passing through the specific beam transmission means to the screen It is composed of a projection lens means, the color selection means is a first color that reflects blue (B) of the polarization beam through the polarization beam separation means to the blue liquid crystal panel and transmits the red (R) and green (G) And a second filtering filter means for reflecting green (G) through the first filtering filter means and the green liquid crystal panel and red (R) passing through the red liquid crystal panel.

In addition, the present invention is a reflection means for condensing the light emitted from the light source means into a parallel light, and a polarization beam separation means for transmitting and reflecting the beam reflected by the reflection means in order to achieve the above object And red (R), green (G), and blue (B) from the polarization beams reflected by the polarization beam separation means, and transmit and reflect to each liquid crystal panel under the control of the signal control means. A dichroic prism means for processing the beam reflected from the reverse direction to be incident on the polarization beam separation means, a? / 4 plate means which is positioned for each liquid crystal panel of the dichroic prism means and imparts a polarization function to the liquid crystal panel; A specific beam transmission means for transmitting only light within a part of the polarization beam reflected by the polarization beam separation means and reflecting more light, and the specific beam transmission means. It is composed of a projection lens means for expanding and projecting the image to the screen, which will be described in detail with reference to Figures 7 to 12 attached to the embodiment as follows.

As such, the schematic diagram uses a Small Beam Angle Transmittance Filter (SF) for the transmission / reflection type liquid crystal projector of the present invention, which is an optical thin film, and its design generally has the following characteristics.

Where T is the transmittance of the optical thin film

λ: wavelength

θ: Incident angle with respect to film plane normal

: Polarization state of incident angle

: Thickness and refractive index of each layer of thin film

In addition, color separation and color synthesis filters generally impart transmissive properties to λ and do not consider θ and λ.

SF to be applied to the optical system of the present invention gives a transmission characteristic only for θ and λ and As an optical thin film which is not taken into consideration, SF is formed between the liquid crystal panel and the projection lens as shown in FIG. The reflected light has a characteristic of reflecting.

On the other hand, the transflective angle region Δθ of the SF is determined as the beam angle region when the electric field is applied, so that all the light at the time of white can be transmitted, and only the light at the time of black can be blocked to increase the contrast.

7 and 8 show the construction of a transmissive liquid crystal projector using SF.

7 is a block diagram of a transmissive liquid crystal projector according to the present invention. As shown therein, a light source 100 emitting white spectrum light, a reflector 101 inducing a path of light emitted from the light source 100, and And a condenser lens 102 for condensing the light induced by the reflector 101 into parallel light, and a liquid crystal panel that receives an electric signal from an electric signal supply unit (not shown) in the projector and changes the degree of scattering of light. 103 and SF means 104 for transmitting only light within a partial angle Δθ of light scattered from the liquid crystal panel 103 when the electric signal is black and reflecting more light, and through the means 104. The projection lens 105 is configured to project an image on the screen 106 in an enlarged manner. The SF means 104 is configured to be positioned between the liquid crystal panel 103 and the projection lens 105.

Referring to Figures 7 and 9 attached to the present invention a transmissive liquid crystal projector configured as described above is as follows.

Light emitted from the light source 100 is guided to the liquid crystal panel 103 by the reflector 101, and the guided light becomes polarized light through the condenser lens 102 and is applied to the liquid crystal panel 103.

Then, the liquid crystal panel 103 scatters light applied by receiving an electrical signal.

When the light is scattered as described above, the SF means 104 generates a beam angle of a small area of the scattered light when the electrical signal applied to the liquid crystal panel 103 is black as in (a) of FIG. 9 described above. It only penetrates the bay and reflects light incident from other angles.

Accordingly, the projection lens 105 displays the image by projecting the small angle of light passing through the SF means 104 onto the screen 106.

In addition, Figure 8 is another configuration of the transmission liquid crystal projector of the present invention, as shown in the light source 100 for emitting the light of the white spectrum, and the reflector for inducing the path of light emitted from the light source 100 ( 101, a color separation mirror 107 for separating the white light guided by the reflector 101 into wavelength bands of red, green, and blue regions, and red, green, and blue in the color separation mirror 107; Color composite mirror unit 109 for synthesizing the light formed in the three liquid crystal panels 108 of red, green, and blue, and the three liquid crystal panels 108 for optically modulating each light separated by the electric signal. And SF means 110 for transmitting only light within a partial angle Δθ of light synthesized and scattered by the color synthesizing mirror 109 and reflecting more light, and an image through the SF means 110. It is composed of a projection lens 111 to enlarge and project on the screen.

Referring to Figures 8 and 9 attached to the present invention a transmissive liquid crystal projector configured as described above are as follows.

When white light is emitted from the light source 100, the white light is separated into wavelength bands of red, green, and blue regions by the three color separation mirrors DM1, DM2, and DM3 of the color separation mirror 107. Next, three red, green, and blue liquid crystal panels 108R, 108G, and 108B are applied.

Then, the three liquid crystal panels 108R, 108G, and 108B optically modulate the light separated into red, green, and blue by electric signals, and each liquid crystal panel 108R (108G) by the optical modulation. The light formed at) 108B is synthesized by the color combining mirrors DM4 (DM5) DM5 of the color combining mirror unit 109.

In this way, the light synthesized by the color synthesizing mirrors DM4, DM5, and DM5 is applied to the projection lens 111 through the SF means 110, as shown in FIG. Light incident within a small angle Δθ is transmitted, and light incident at an angle greater than that is reflected.

Accordingly, the projection lens 111 displays the image by expanding and projecting the incident small angle light onto the screen.

At this time, as shown in FIG. 8, when the SF means 110 is formed between the color synthesizing mirror DM6 and the projection lens 111, only one sheet of SF is used, and a dotted line portion 110 'is used. Two SFs are used in the case of located in the front side, and three SFs are used in front of the liquid crystal panel 108 and the color combining mirror unit 109.

On the other hand, Figure 10 is a configuration of the present invention a reflective liquid crystal projector, as shown in the condensing lens 121 to collect the light emitted from the light source 120 to make parallel light and the condensing lens 121 Red (R), green (G), and blue (B) are selected from the polarization beam separation means 122 for transmitting and reflecting parallel light therethrough and the polarization beam projected by the polarization beam separation means 122. Transmitted and reflected by the liquid crystal panel 123-1R (123-1G) 123-1B, and the beam reflected from the liquid crystal panel 123-1R (123-1G) 123-1B is reversely processed. The liquid crystal panel 123-1R (123-1G) 123-1G (123-1B) of the color screening unit 123 to be incident on the polarization beam separation unit 122 and the liquid crystal panel 123-1B of the color screening unit 123 are positioned to provide a liquid crystal. Λ / 4 plate 124 for providing a polarizing function to the panel 123 and S for transmitting only light within a partial angle Δθ of the polarizing beams reflected by the polarizing beam splitter 122 and reflecting more light. It consists of a projection lens 126 for projecting the image passing through the F means 125 to the screen 127, the color selection unit 123 is the blue of the polarization beam through the polarization beam separation means 122 ( B) reflects through the blue liquid crystal panel 123-1B and transmits the red (R) and green (G) light through the first color filter 123-2 and through the first color filter 123-2. Green (G) is reflected by the green liquid crystal panel 123-1G, and red (R) is composed of the second color separation filter 123-3 passing through the red liquid crystal panel 123-1R. The plate 124 is not provided for each of the liquid crystal panels 123-1R, 123-1G, and 123-1B, and one λ / 4 plate 124 'is placed in front of the color screening unit 123 like a dotted line. You can also install a bay.

The present invention is a reflection type liquid crystal projector described as follows.

First, the function of λ / 4 full rate is as follows.

When the λ / 4 plate is not used in the reflection type liquid crystal projector, the efficiency of the optical system using the polarization beam separation means is reduced.

That is, (a) of FIG. 12 is a basic structure diagram of the reflective optical system, and a half mirror is used as shown therein. In this case, the light efficiency is Io / 4 when the amount of light emitted from the light source unit is Io. Can be incident on the projection lens, which is a level of light efficiency corresponding to 25% of the aperture ratio of the transmissive liquid crystal projector.

Therefore, it is difficult to expect an increase in light efficiency, which is the purpose of using a reflective liquid crystal projector.

Therefore, in order to fully realize the increase in brightness, which is the biggest advantage of the liquid crystal projector, a reflective optical system using a λ / 4 plate and polarization beam separation means is designed as shown in FIG.

That is, this imparts a polarization function to the liquid crystal projector without polarization conversion function. The polarization beam is separated into P waves and S waves through the polarization beam path, and the S waves are reflected and passed through the λ / 4 plate. Direction of circular polarization.

When the circularly polarized state passes through the liquid crystal panel (PDLC) and is incident on the λ / 4 plate again, the polarized state becomes a counterclockwise circularly polarized state, and this state passes through the λ / 4 plate and is converted into a P wave. And enters the projection lens as P-wave through the polarization beam separation means.

Referring to FIG. 10, the present invention is a reflection type liquid crystal projector using λ / 4 plate having such a function.

In the reflective optical system of the present invention configured as described above, the light emitted from the light source 120 is collected by the condenser lens 121, and then becomes parallel light, which is incident on the polarization beam separation unit 122.

The incident light is polarized after passing through the polarization beam separation unit 122, and then the blue color B is λ / 4 plate 124B through the first color filter 123-2 of the color screen unit 123. By the polarization function is given by the blue liquid crystal panel 123-1B is reflected and the red (R) and green (G) is incident to the second color filter (123-3).

In addition, the green (G) incident on the second color filter 123-3 is reflected by the green liquid crystal panel 123-1G after being polarized through λ / 4 plate 124G and is red (R). Is transmitted to the red liquid crystal panel 123-1R through the λ / 4 plate 124R.

Thus, the color signals applied to the red, green, and blue liquid crystal panels 123-1R, 123-1G, and 123-1B are again λ / 4 plate 124R, λ / 4 plate 124G, and λ / 4 plate. Reflected through 124B, the light is incident on the polarization beam separation means 122 through the second and first color separation filters 123-3 and 123-2, and the polarization beam separation means 122 is incident light. Is reflected to the screen 127 through the SF means 125, wherein the light incident into the small angle (Δθ) of the reflected light is transmitted through the SF means 125, but the light incident at an angle greater than Reflected by the SF means 125.

Accordingly, the projection lens 126 enlarges and projects the incident small angle light onto the screen 127 to display an image.

In addition, FIG. 11 is another configuration of the reflective liquid crystal projector of the present invention, and as shown therein, a reflector 120-1 for condensing light emitted from the light source 120 to make parallel light, and the reflector 120-. Polarization beam separation means 122 for transmitting and reflecting parallel light reflected by 1) and red (R), green (G), and blue (B) from the polarization beam reflected by the polarization beam separation means 122. Screening and transmitting the light reflected from the liquid crystal panel 129 under the control of the control unit 130, and processing the beam reflected from the liquid crystal panel 129 inversely to enter the polarization beam separation means 122. [Lambda] / 4 which is positioned for each of the liquid crystal panels 129R (129G) and 129B of the prism 128 and the color discriminating prism 128 to impart a polarization function to the liquid crystal panels 129R (129G) and 129B. Only the light within a part of the angle Δθ of the plate portion 124 and the polarization beams reflected by the polarization beam separation means 122 is transmitted. The above light is composed of the SF means 125 for reflecting the light and the projection lens 126 for projecting the beam passing through the SF means 125 onto the screen 127. The? / 4 plate portion 124 Instead of the respective liquid crystal panels 129R, 129G, and 129B, only one λ / 4 plate portion 124 'may be provided in front of the dichroic prism 128 as in the dotted line portion.

When the light is emitted from the light source 120, the reflective liquid crystal projector according to the present invention is condensed by the reflector 120-1 and then incident to the polarization beam separation unit 122 as parallel light.

The incident light is reflected by the polarization beam splitter 122 and is incident on the color discriminating prism 128, and the incident light is separated into red (R), green (G), and blue (B) to form liquid crystals. The enemy under the control of the control unit 130 through the / 4 plate portion 124R, the λ / 4 plate portion 124G, and the λ / 4 plate portion 124B located for each of the panels 129R, 129G, and 129B, It is projected onto the liquid crystal panels 129R (129G) and 129B of green and blue. The projected light is reflected by the liquid crystal panels 129R, 129G, and 129B again and is incident on the projection lens 126 through the color discriminating prism 128 and the polarization beam separation means 122.

At this time, the light incident on the projection lens 126 is the light passing through the SF means 125, the SF means 125 is incident into a small angle (Δθ) of the light reflected by the polarization beam separation means 122 Transmitting light is incident, but light incident at an angle greater than that reflects.

Accordingly, the projection lens 126 displays the image by expanding and projecting the incident light onto the screen 127.

10 and 11, the λ / 4 plate portion 124R is a device designed on the basis of red wavelength as a polarization conversion means of the red (R) liquid crystal panel 129R. The lambda / 4 plate portion 124G is designed based on the green (G) liquid crystal panel 129G, and the lambda / 4 plate portion 124B is designed based on the blue (B) liquid crystal panel 129B.

In addition, when λ / 4 plate is not used for each liquid crystal panel 129R, 129G, 129B, as shown in FIG. 11, only one λ / 4 plate part 124 'is used for the dotted line. In this case, it means that it is set for all visible light.

As described above, in the present invention, a transmissive liquid crystal projector can improve contrast while maintaining brightness by using a filter (SF) that passes light incident at a specific angle. In a reflective liquid crystal projector, SF, λ / 4 plate, There is an effect that can improve both the brightness and contrast by using the polarizing beam separation means.

Claims (4)

A light source means for emitting white spectrum light, a reflecting means for guiding a path of light emitted from the light source means, a light condensing means for condensing the light induced by the reflecting means to make parallel light, an electric signal from a projector A liquid crystal panel configured to form an image by adjusting a scattering degree of light incident from the light collecting means, a specific beam transmitting means for transmitting only light incident within a specific angle Δθ among the light scattered from the liquid crystal panel, A transmissive / reflective liquid crystal projector comprising: projection lens means for projecting an image through a beam transmitting means on an enlarged screen. The transmissive / reflective liquid crystal projector according to claim 1, wherein the liquid crystal panel is a transmissive liquid crystal panel. The transmissive / reflective liquid crystal projector according to claim 1, wherein the liquid crystal panel is a reflective liquid crystal panel. The liquid crystal panel of claim 1, further comprising: color separation means for separating colors into three areas of the liquid crystal panel R, G, and B, and color combining means for synthesizing the color separated by the color separation means. Type liquid crystal projector.