JPH07322303A - Rear projection type projection television - Google Patents

Abstract

PURPOSE:To improve a left and right separation degree on a screen and to clarify stereoscopic visibility in a rear projection type stereoscopic projection system. CONSTITUTION:In rear projection type projection for performing stereoscopic display based on binocular parallax, at least a pair of projectors provided with a projection lens for projecting video images, a Fresnel lens 3 provided with the coating thickness of the internal reflection prevention coating of visible region light beams in video light beams on a light emission side corresponding to the incident angle of the video light beams from the projectors and a lenticular lens 2 for dispersing the video light beams from the Fresnel lens 3 in horizontal and vertical directions are provided. Thus, compared to the Fresnel lens without AR coating, the left and right separation degree of several dB is improved and the stereoscopic visibility is raised.

Description

Detailed Description of the Invention

[0001]

[0001]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear-projection type stereoscopic image device, and more particularly to a rear-projection type stereoscopic device capable of reducing leakage between left and right images for producing stereoscopic images and obtaining an excellent stereoscopic effect. Regarding projection TV.

[0003]

[0002]

[0004]

2. Description of the Related Art A conventional rear projection type stereoscopic image device is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-89236, and as shown in FIG. The phase compensating plate frame 21 on the adjusting device 20 for adjusting the mounting angle of the frame for the left polarized light and the right polarized light
Then, the contrast ratio is increased by setting the optical phase difference to an appropriate value there, and then the circular Fresnel lens 18 converts the parallel rays into substantially parallel rays, and the lenticular lens sheet 19 diffuses the parallel rays in the vertical and horizontal directions. By being dispersed, a screen that can withstand vision from multiple directions is configured and the image that is the basis of the stereoscopic image is projected.

[0005]

Therefore, a stereoscopic image can be recognized by observing through the polarizing glasses 22 having a phase difference of 90 degrees to the left and right. There is also an example in which a reflection mirror is provided between the projection device and the screen in order to reduce the depth of the rear projection type stereoscopic image device. On the other hand, in order to observe a stereoscopic image with high image quality, the image quality of the image source itself must be good together with the degree of separation of the image source on the left and right, but the image quality of the stereoscopic image on the screen that can be observed from the polarizing glasses is improved There is a need.

[0006]

Therefore, FIG. 10 shows an example of the actual measurement result in an actual rear projection type stereoscopic image device. This is a measurement system in which only the screen including the circular Fresnel lens 18 and the lenticular lens 19 in the conventional rear projection type stereoscopic image device shown in FIG. B. With and without a screen, a polarizing plate was substituted for the position of the screen. It is a comparative measurement graph with the case without a screen. The horizontal axis shows the diagonal size ratio of the rectangular screen, and the vertical axis shows the ratio separation between the orthogonal component S and the parallel component P of the projected light beam. As a result, the deterioration of the degree of separation of 10 dB or more can be read by the existence of the conventional screen itself. Due to this deterioration of the degree of separation, it was confirmed that a rainbow was generated in the peripheral portion of the screen with this screen.

[0007]

[0005]

[0008]

Therefore, the problem to be solved by the present invention is to improve the image quality of a stereoscopic image in a rear projection type stereoscopic image device. Specifically, by changing the configuration of the Fresnel lens as a component of the screen, it is possible to obtain the image quality of a stereoscopic image that cannot be achieved by the conventional Fresnel lens.

[0009]

[0006]

[0010]

A rear projection type projection for stereoscopic display based on binocular parallax according to the present invention comprises:
At least two types of projectors including a projection lens for projecting an image, and a coating thickness of an internal reflection preventing coat of visible ray in the image ray on the emission side according to an incident angle of the image ray from the projector It is characterized by comprising a Fresnel lens and a lenticular lens that disperses image light rays from the Fresnel lens in the horizontal and / or vertical directions.

[0011]

Further, according to the present invention, the rear projection type projection for stereoscopic display based on the binocular parallax includes a projector of at least three colors including a projection lens for projecting a video signal, and an incident angle of a video light beam from the projector. Accordingly, a Fresnel lens having a coating thickness of an internal antireflection coat of visible light in the image light on the output side and a lenticular lens for dispersing the image light from the Fresnel lens in the horizontal and vertical directions are provided. Is characterized by.

[0012]

Furthermore, the coat thickness t of the reflection coat of the Fresnel lens is

[0013]

[Equation 2] Where λ is approximately the center wavelength of visible light in the image light beam, n0 and n1 are the refractive indices of the layers of the reflection coat, and θ0 is the incident angle of the image light beam to the Fresnel lens and the exit side. The incident angle at the exit surface is defined by the tooth angle.

[0014]

The rear projection type projection television for stereoscopic display based on the binocular parallax according to the present invention includes at least two or three types including a projection lens for projecting an image.
A color projector and a Fresnel lens surface on the exit side of the image beam from this projector, and an internal antireflection coat with a certain coat thickness that minimizes the amount of internal reflection due to the incidence of the image beam on the exit side. And a lenticular lens that disperses image light rays from the Fresnel lens in the horizontal and vertical directions.

[0015]

[0010]

[0016]

[Operation] When the screen of the rear projection type stereoscopic image device is viewed using the polarized glasses, the images for the right eye and the left eye are emitted from the respective projectors, and the projection light from the projectors is incident on the screen. The deterioration of the degree of separation of the images for the right eye and the left eye caused by the different angles was changed by changing the coating thickness of the internal antireflection coating of the Fresnel lens for each incident angle. The deterioration can be suppressed, and a stereoscopic image from the light emitted from the Fresnel lens through the lenticular lens can be recognized as a clear stereoscopic image over the entire screen.

[0017]

This projector uses a total of six CRTs of two types of RGB and a total of three CRTs of RGB.
Only when the driving method is different from the case of using the RT, the degree of recognition from the viewer is a slight difference, and no problem occurs.

Further, since the coating thickness of the internal antireflection coating of this Fresnel lens is changed according to a predetermined incident angle, if the Fresnel lens is manufactured according to this mathematical formula, an ideal Fresnel lens is produced. It enables the best 3D viewing.

[0019]

Further, even if the internal reflection preventing coat of the Fresnel lens is set to a predetermined thickness so that the internal reflection of the incident light beam does not depend on the incident angle, the Fresnel without the internal reflection preventing coat is obtained. The degree of left-right separation is superior to that of a lens, and the degree of recognition as a stereoscopic image is higher.

[0020]

[0013]

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a side view of a rear projection type stereoscopic image device of the present invention as an embodiment.

In the figure, 1 is a screen that emits a stereoscopic image, 2 is a lenticular lens that diffuses and disperses input projection light over the entire surface, particularly in the horizontal and vertical directions, and 3 is substantially the incident projection light in the horizontal direction. The Fresnel lens that emits light in parallel is AR-coated on the emission side, and the lenticular lens 2 and the Fresnel lens 3 form the screen 1.

[0024]

The projector is composed of the following. 4 is a total reflection mirror, 5a and 5b are exit lenses, 6a and 6b are projection lenses, and exit lenses 5a and
The projection lens 5b, the projection lenses 6a and 6b, and the lens in the cooling seat 7 constitute a projection lens to magnify and project the CRT image. 7
Reference numerals a and 7b are cooling seats composed of a lens and a cooling means for preventing the temperature of the exit surface of the CRT 8 from increasing in temperature. 8a and 8b
Is a cathode projection tube (CRT), 9a and 9b are horizontal / vertical deflection circuits of the CRT, and 10a and 10b are the CRT8.
In the convergence correction circuit of, 11a and 11b are C
It is a drive circuit of RT video signal, each a is for the right eye,
Each b operates for the left eye. In addition, since there are three color images in the depth direction of each a and each b, a projection lens, a CRT, a drive circuit, etc. are arranged for each of the three colors for red (R), green (G), and blue (B). Has been done.

[0025]

Further, 12 is an exterior cabinet of the rear projection type stereoscopic image device, and 13 is a caster convenient for installing, delivering and arranging the rear projection type stereoscopic image device.

The operation of the above-described structure will be described below.

First, the drive circuits 11a and 11b convert the right-eye video signal and the left-eye video signal into CRTs 8a and 8b.
Driving, the video signals of the respective colors are emitted as radiated light from the fluorescent display surfaces of the CRTs 8a and 8b, the radiated light is enlarged by the projection lenses 6a and 6b of the projection lens, and totally reflected by the reflection mirror 4. The light is incident on the Fresnel lens 3 and is projected on the screen 1 emitted from the lenticular lens 2.

[0028]

At this time, as shown in FIG. 1, an offset is provided on the optical axis of each radiated light of the video signal for the right eye and the video signal for the left eye, and the image is projected on the screen 1. This is a 6-tube CRT
In order to obtain a stereoscopic image, the space of the CRT for the right eye cannot be matched with the space of the CRT for the left eye, and not only in the case of RGB three colors, but also due to the Scheimpflug law of each right eye and left eye optical system. This is to compensate for the incline.

Here, referring to FIGS. 2 to 4, FIG. 7 and FIG. 8 showing how the projection light projected by the reflection mirror 4 enters and exits the Fresnel lens 3, only the conventional acrylic member is used. The description will be made while comparing the Fresnel lens in the case of 1 and the Fresnel lens in the case of the acrylic member of the present invention and the AR coat.

[0030]

FIG. 2 shows an example in which incident light enters a conventional acrylic member, is transmitted / reflected by the Fresnel lens surface, and the reflected light is reflected / transmitted by the incident surface. The angular relationship in this case shows a state diagram at a position of 15.5% when the peripheral edge of the screen is set to 100% from the center of the screen.

[0031]

There, incident light A becomes transmitted / emitted light B and reflected light C. The reflected light C has 4% of the energy of the incident light A due to the refractive index. The reflected light C reaches the incident surface of the acrylic member of the Fresnel lens, and is split into transmitted / emitted light D and reflected light E at the incident surface. This reflected light E is an S wave (Senkrecht Polarized Light Wave:
Vertically polarized light wave) and P wave (Parallel Polarized Light Wa)
ve: parallel polarized light wave), the polarization axis is deviated due to the difference in reflectance, but since it has only 0.24% energy of the initial incident light A, outside the Fresnel lens,
Even if the light is emitted from any part, it hardly affects the deterioration of the separation degree for the right eye and the left eye. This is considered to be one of the reasons why the rainbow does not occur near the center of the screen 1.

Here, the degree of separation means the degree of separation = 20 log.
It is represented by (orthogonal / parallel) and is measured from the ratio of S wave (orthogonal) and P wave (parallel).

[0033]

More specifically, the reflected light E of weak energy causes total reflection in most cases on the exit Fresnel surface of the acrylic member, and then returns to the entrance surface of the acrylic member and is further reflected three times. Repeat about a degree. In the vicinity of the center of the circular Fresnel lens constituted by the acrylic member, that is, near the center of the screen, the inclination angle of the Fresnel lens surface is gentle. It is thought that there is little collapse.

Next, FIG. 3 shows 85.3% when the center of the screen is 100% from the peripheral edge of the screen.
The state diagram of the position of is shown.

[0035]

Here, the Fresnel blade angle of the Fresnel lens surface is about 55 degrees and the Fresnel apex angle is about 50 degrees. Incident light a, b, c is a Fresnel surface, and outgoing / transmitted light a1, b
1, c1 and reflected light a2, b2, c2. The axes of polarization of the reflected lights a2, b2, and c2 are deviated due to the difference in reflectance between the P wave and the S wave. The reflected lights a2, b2, and c2 are transmitted, reflected, and refracted on the Fresnel surface while being totally reflected by the flat surface on the incident surface of the Fresnel lens. The totally reflected light a3, b3, c3 (not shown because it becomes complicated)
Has a phase difference between the P wave and the S wave, and is elliptically polarized. Further, the reflected lights a3, b3, and c3 are emitted from the Fresnel surface as emitted lights a4, b4, and c4 (not shown), respectively. The emitted lights a4, b4, c4 are
Due to the large Fresnel blade angle, the initial incident light a, b, c
Of 8.6%, and the polarized light is elliptically polarized light instead of linearly polarized light. This emitted light a4, b
It is considered that the vector components 4 and c4 in the horizontal direction (main dispersion direction of the lenticular lens) are the main cause of the deterioration of the degree of separation.

[0036]

As described above, looking at the collapse of the polarization from the center of the screen toward the peripheral end of the screen, the Fresnel pitches of the central part and the peripheral part are the same because of the simplicity and ease of manufacturing the circular Fresnel lens. Since the Fresnel blade angle is increased toward the periphery, there is a phenomenon in which the degree of separation deteriorates from the center of the screen toward the periphery.

[0037]

Specifically, it is possible to confirm that bleeding is occurring from the central portion to the peripheral portion. At that time, it is shown that the video signal, especially black, is sufficiently sunk in the vicinity of the center as compared with the other peripheral portions and the degree of separation is good. As described above, the causes of deterioration of the degree of separation in the Fresnel lens are
It can be said that this is internal reflection due to the Fresnel blade angle on the Fresnel surface. Therefore, it has been discovered that it is necessary to apply an antireflection coat (AR coat) to the Fresnel surface in order to prevent this internal reflection.

[0038]

The path of light rays by this AR coat will be examined.

In FIG. 4, mediums N0 (Fresnel material), N1
(When the film thickness of the AR coat is t), N2 (air outside the emission), when the light ray A is incident on the medium material having the refractive index n0, n1, and n2 at the incident angle θ0, the medium N1 It is assumed that the reflected light becomes B, and the emitted light D and reflected light from the medium N2 are emitted as C. Therefore, the reflected light B and the reflected light C
If the phase difference between the reflected light and the wavelength is half the wavelength λ of the light beam, the reflected light B
And the reflected light C cancel each other out, and the reflected light is reduced.

[0040]

That is,

[0041]

[Equation 3] from now on,

[0042]

[Equation 4] However, θ1, P1 (adc) and P0 (ab) indicate the refraction angle and the optical path length shown in FIG.

From the above, for the thickness of the AR coat, the optimum coating film thickness can be set from the calculated value. Further, the incident angle θ 0 actually represents the incident angle of the image light beam on the Fresnel surface of the Fresnel lens.

[0044]

Therefore, if a predetermined thickness is set according to the angle of incidence on the AR coat, polarized light is not generated in the Fresnel lens, and the emitted light of the AR coat is internally reflected and emitted. The ratio of emitted light whose polarization axis is displaced is reduced, and the degree of separation is not deteriorated.

[0045]

Calculation of this film thickness for an actual screen is as follows.

[0046]

[Table 1] However, the distance from the center means the distance from the center of the screen to the upper right / upper left direction, and (%) indicates the ratio to the end.

The circular Fresnel lens is an acrylic material, and the Fresnel lens is dipped in an AR coating solution (eg magnesium fluoride MgF),
Using a pulling machine, and pulling while rotating at a constant speed to make a film.

[0048]

From the above calculation results, an example will be described below in which the film thickness is fixed and the degree of separation is improved. In particular, in order to improve the degree of separation around the screen, a film thickness of 120
We examined the results in the cases of nm, 131 nm, and 142 nm.
131nm, 142nm, 120nm compared to the case without R coat
It was found that the resolution was improved little by little in the order of, and the degree of separation at the periphery was the best at 120 nm, and it was improved by about 5 dB in the entire region.

As an example, the AR coat film having a constant film thickness is formed by an impregnation method. The Fresnel lens is dipped in the AR coat material, pulled up at a constant pulling speed, and dried.
After that, it can be realized by the method of cutting and deleting the other side of the Fresnel surface.

[0050]

Regarding the measurement of the film thickness, there is a spectrophotometer method, in which light having different wavelengths is applied to the coated surface as sample light, the reflectance at that time is measured, and the film thickness is determined from the wavelength having the lowest reflectance. calculate. In addition, as a visual method, when the green color is reduced in reflection, blue and red are also slightly reflected, so by visually observing this color and comparing which wavelength is reduced reflection from the reference sample while comparing Judgment is made and the film thickness is calculated. It is also possible to measure with a camera and a spectrometer. A ray of light is applied to the Fresnel lens surface from a light source, the reflected light is incident on a camera, the output of the camera is digitized by a spectrometer, and compared with a standard antireflection characteristic for measurement.

[0051]

Next, a method of coating a film thickness according to the incident angle will be described with reference to FIG. In an example using a vacuum deposition method, in a vacuum atmosphere, a Fresnel lens 24 placed on a rotating plate with a Fresnel surface facing upward, a rotation device 25 that rotates with its rotation axis aligned with the optical axis of the circular Fresnel lens, and its The vapor deposition apparatus 23 is provided with a vapor deposition pot in the upper part around the Fresnel lens. Therefore, if the center of the circular Fresnel lens is placed on the rotation axis of the rotation device 25 and rotated to raise the temperature of the vapor deposition chamber of the vapor deposition device 23, the vapor deposition film is proportional to the square of the distance from the vapor deposition chamber. A thick coating accumulates on top of the Fresnel lens. This vapor deposition time, vapor deposition kettle temperature, and rotating device 25
By appropriately setting the rotation speed and the distance between the Fresnel and the evaporation pot, this apparatus completes the AR coating based on the above calculated values.

[0052]

However, since a predetermined film thickness with respect to the distance from the center of the Fresnel lens is required, if the position of the vapor deposition pot can be moved up and down and forward and backward, the AR coating can be efficiently performed.

As a method of coating a film thickness according to the incident angle, the molten AR coating material is dropped on the center of the circular Fresnel lens rotated on the axial center so that the film on the peripheral portion rather than the center portion. There is also a method of increasing the thickness, and various selections can be made from the efficiency, time, cost, etc.

[0054]

As a summary of the above, referring to FIG. 7 and FIG.
The characteristics of light rays depending on the presence or absence of the AR coat will be described.
FIG. 7 shows a case without an AR coat. When the P wave and the S wave are incident at an angle θ, the first transmitted light is also emitted as a ray having the same angle θ, but the reflected light is at an angle α and The second transmitted light is emitted at the angle β after being reflected and polarized at the angle β. Since the first and second emitted lights are viewed by the polarized glasses, the degree of separation is totally deteriorated and the stereoscopic view of the stereoscopic image is impaired.

[0055]

On the other hand, FIG. 8 shows the case where the AR coating is provided. When the P wave and the S wave are incident at an angle θ, the transmitted light is also emitted as a light beam having the same angle θ, and the Fresnel portion and AR
Since the reflected light rays at the contact portion of the coat portion and the emission portion of the AR coat are extremely smiling, they can be almost ignored. Therefore, if this emitted light is projected through the lenticular lens, the stereoscopic view of the stereoscopic image can be clearly recognized without impairing the degree of separation.

[0056]

Another embodiment of a projection television of the one-fold bending type using a mirror will be described with reference to FIG.

In the figure, 30 is a cathode grid drive circuit of the CRT 32, 31 is a horizontal / vertical deflection circuit or conversion circuit of the CRT 32, and 34 is a CRT.
A projection lens including a lens group such as a concave lens 33 of a liquid-cooled coupling that suppresses the temperature rise of the tube surface of No. 3, and a correction lens,
Reference numeral 35 is a polarizing lens, 36 is a reflecting mirror that totally reflects the image light beam, and 37 is an AR coating having a different thickness or a predetermined constant AR coating on the exit side according to the incident angle of the light beam. Is a circular Fresnel lens having a light condensing function, 38 is a lenticular lens having a diffusion function for widening the viewing angle in the left, right, up, and down, 39 is a cabinet forming the exterior of the projection TV, and 40 is the installation and movement of the projection TV. It is a caster that facilitates.

[0058]

Here, the CRT 32 is composed of three tubes of red (R), green (G) and blue (B), and is equipped with a drive circuit 30, a projection lens 34, a polarizing lens 35, etc. for each color. The video signal of each color is projected. The video signals for the left eye and the right eye are alternately driven for each field, for example, and are driven by the polarizing lens 35 so as to have a polarization angle of 0 degree and 90 degrees in synchronization with the drive, It is projected on the screen via the reflection mirror 36. Then, polarized glasses are required, and a stereoscopic image can be viewed on the screen with the polarized glasses having an optical filter having a 90-degree phase difference between the left eye and the right eye.

[0059]

This three-tube type rear projection type three-dimensional projection television is mechanically lighter in weight and smaller in volume than the six-tube type, so that the degree of freedom in arrangement is increased and the incident angle to the Fresnel lens is increased. However, since the offset of the incident angle is not necessary and the optimum thickness can be set more precisely, the deterioration of the above-mentioned separation degree is lessened and higher image quality can be observed. However, in order to prevent flicker and coarse image quality, the drive circuit using an electric circuit may require speeding up or signal interpolation for the horizontal / vertical deflection circuit and the drive circuit for the video signal.

[0060]

Regarding the thickness of the AR coat on the Fresnel lens itself in the three-tube type, the generating means for making the coat thickness thicker as the incident angle of the projection light of the video signal becomes larger, even if the numerical value is different. It can be achieved in a similar way to the tubular type.

Further, this three-tube type projection television is mechanically constructed in the same manner as a conventional two-dimensional image device, and the deflection lens 35 and the Fresnel lens 37 may be added / changed, which makes it easier to stereoscopically display. You can experience the sight. Moreover, the stereoscopic view extends from the center of the screen to the four corners.
It is possible to embody a high-quality, high-quality, high-separation solid while preventing the occurrence of bleeding.

[0062]

[0037]

[0063]

As described above, the image quality of a stereoscopic image can be improved in the rear projection type stereoscopic image device as described above. In particular, since the thickness of the AR coat of the circular Fresnel lens is changed around the screen of the device, the amount of reflection and the amount of polarization due to the reflected light on the Fresnel surface can be reduced, and the left / right separation is improved. By observing the left and right images with the respective glasses, a clear stereoscopic image can be recognized.

[0064]

Further, as described above, it is possible to prevent the stereoscopic view on the screen from being broken, and it is possible to obtain a good stereoscopic image even in a projection television using a Fresnel lens.

Furthermore, the Fresnel lens has an AR of a certain thickness.
Even when a coat is applied, the degree of separation can be made higher than that of the conventional one in addition to the ease of manufacturing, and thus the stereoscopic effect of a stereoscopic image can be sufficiently recognized.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of a rear projection type projection television of the present invention.

FIG. 2 is a schematic optical path diagram when incident light is incident on an acrylic member of a Fresnel lens of a conventional example.

FIG. 3 is a schematic optical path diagram when incident light is incident on the acrylic member of the Fresnel lens of the conventional example.

FIG. 4 is a conceptual diagram of an optical path according to the present invention.

FIG. 5 is a diagram showing a method for producing a coat of an AR coating material according to the present invention.

FIG. 6 is a configuration diagram of a rear projection type projection television according to another embodiment of the present invention.

FIG. 7 is a conceptual diagram of an optical path when there is no AR coat in the conventional example.

FIG. 8 is a conceptual diagram of an optical path when the AR coat of the present invention is provided.

FIG. 9 is a configuration diagram of a conventional projection type stereoscopic projector.

FIG. 10 is a graph showing the difference in the degree of separation depending on the presence or absence of a screen.

[Explanation of symbols]

 1 Screen 2, 38 Lenticular Lens Sheet 3, Circular Fresnel Lens 4, 36 Reflecting Mirror 15, 16 Projector 21 Phase Compensation Frame 23 Evaporator 37 Circular Fresnel Lens

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nozomi Kikuchi 4-15-5 Omorinishi, Ota-ku, Tokyo Pioneer Co., Ltd. Omori Plant (72) Inventor Hirokazu Izumi 4-15 Omorinishi, Ota-ku, Tokyo 5 Pioneer Co., Ltd. Omori Factory (72) Inventor Shoji Toriumi 4-15 Omori Nishi, Ota-ku, Tokyo Pioneer Co. Ltd. Omori Factory (72) Inventor Mana Akagi 4-Omori Nishi, Ota-ku, Tokyo No. 15-5 Pioneer Co., Ltd. Omori Factory (72) Inventor Takahide Hamaguchi 4-15-5 Omori Nishi, Ota-ku, Tokyo Pioneer Co., Ltd. Omori Factory

Claims (6)

[Claims] 1. A rear projection type projection television for stereoscopic display based on binocular parallax, wherein at least two types of projectors including a projection lens for projecting an image, and an angle of incidence of an image ray from the projector, A Fresnel lens having a coating thickness of an internal antireflection coating for visible light in the image light on the output side, and a lenticular lens for dispersing the image light from the Fresnel lens in the horizontal and vertical directions. Rear projection type projection television. 2. A rear projection type projection television for stereoscopic display based on binocular parallax, wherein a projector of at least three colors including a projection lens for projecting an image, and an angle of incidence of an image ray from the projector, A Fresnel lens having a coating thickness of an internal antireflection coating for visible light in the image light on the output side, and a lenticular lens for dispersing the image light from the Fresnel lens in the horizontal and vertical directions. Rear projection type projection television. 3. The rear projection type projection television according to claim 1 or 2, wherein the projector has a CRT and a projection lens for each of red, green and blue. 4. The coat thickness t of the reflection coat of the Fresnel lens is given by The rear projection type projection television according to claim 1 or 2, wherein: Where λ is approximately the central wavelength of visible light in the image light, n0 and n1 are the refractive indices of the layers of the reflection coat, and θ0 is the angle of incidence of the image light on the Fresnel surface of the Fresnel lens. 5. A rear projection type projection television for stereoscopic display based on binocular parallax, wherein at least two types of projectors including a projection lens for projecting an image, and a Fresnel lens surface on the exit side of the image light beam from the projector are provided. A Fresnel lens having an internal antireflection coating having a constant coat thickness on the emission side, which has a minimum internal reflection amount upon incidence of the image light beam, and the image light beam from the Fresnel lens is dispersed in the horizontal and vertical directions. A rear projection type projection television characterized by having a lenticular lens. 6. A rear projection type projection television for stereoscopic display based on binocular parallax, a projector of at least three colors including a projection lens for projecting an image, and a Fresnel lens surface on the exit side of the image light beam from the projector. A Fresnel lens having an internal antireflection coating having a constant coat thickness on the emission side, which has a minimum internal reflection amount upon incidence of the image light beam, and the image light beam from the Fresnel lens is dispersed in the horizontal and vertical directions. A rear projection type projection television characterized by having a lenticular lens.