JPH0572631A - Front projection device - Google Patents

Abstract

PURPOSE:To improve such a problem that light quantity scattered to the outside of a viewing side from a screen is much and the utilizing efficiency of light is low in the conventional manner and to realize the high-gain and bright screen having wide range which is properly viewed in a front projection device which requires a smaller space at the back part of the screen in comprison with a rear projection device. CONSTITUTION:A micro lenticular lens for scattering 5 is formed on the light incident surface of a transparent sheet 3 on the screen surface and a reflecting surface 6 is formed at the almost intermediate position of a focal distance at the back part of the lens. A light beam projected toward the screen from a projection lens 2 at the front part of the screen is made incident on the lens 5, transmitted through it, reflected on the reflecting surface 6 and returned. Then, it is passed again through the lens 5 in a reverse direction, scattered and emitted to the viewer side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front projection device. Specifically, a projection lens is arranged on the front surface of the diffuse reflection type screen, and the projection lens is inserted through the projection lens with respect to the diffuse reflection type screen located at the convergence plane position of the projection light projected through the projection lens. The present invention relates to a front projection device adapted to project an image.

More specifically, the present invention has a wide horizontal viewing range and a small color shift (color change when the screen is viewed obliquely from the lateral direction) even in a front projection device. The present invention relates to a large-sized front projection device capable of obtaining a brighter (about 2.5 times) image as compared with that of the related art.

[0003]

2. Description of the Related Art In order to observe an image of a projection device which normally exceeds 120 inches in a bright room, a rear projection device is brighter and has less color shift than a front projection device. FIG. 8 is a side view showing a conventional example of a rear projection device. FIG. 12 is a schematic top view of an optical system of a conventional lenticular lens diffusion type rear projection device.

A basic schematic view of an optical system of a conventional rear projection device is as shown in FIGS. 8 and 12, and an elliptical microlenticular lens is provided on a light incident surface. For details, see USP. No. 4,563,056, the description thereof is omitted. The diffusion method using a lenticular lens has a higher light utilization efficiency than other diffuse reflection diffusion methods, so there is little color shift in a wide range of suitable viewing, a high screen gain and a bright image can be obtained. Then lenticular
The lens diffusion type has not been put to practical use.

FIG. 13 is a schematic top view of an optical system of a conventional front projection device of diffuse reflection type. In the figure, 1 is a CRT (cathode ray picture tube), 2 is a projection lens, and 4 is optical axis reflected light. The conventional front projection device exceeding 120 inches screens the projected light as shown in FIG.
Since the light is diffusely reflected on the surface of the SK, the following problems occur.

(1) In the vicinity of the edge of the screen SK, the optical axis reflected light 4 is reflected outward in the direction indicated by the arrow. Therefore, in order to obtain a wide suitable viewing range, the diffuse reflection diffusion angle is Need to be bigger. Therefore, a large amount of light is scattered to the outside and is lost, and the amount of light traveling toward the viewing side is reduced. That is, the screen gain decreases and the screen becomes darker,
It was uneconomical to see more in a bright room, because we had to increase the number of light sources.

(2) In FIG. 13, the angle of convergence θ of the projection light
However, since it is usually 4 to 5 degrees, if the screen gain is increased, a color shift occurs. When viewed from the direction A, the red color is emphasized more than the blue color, and when viewed from the direction B, the blue color is emphasized. This phenomenon is called color shift, which significantly deteriorates the image quality. For this reason, the diffuse reflection diffusion angle is extremely widened, so that the screen gain is lowered and the screen becomes dark.

On the other hand, the rear projection device has the following problems when it is installed in a room.

(1) As shown in FIG. 8, the screen SK
Requires a large space behind, and for example, in order to install a 110-inch rear projection device in a conference room measuring 8 m square, a space of about 2 m is needed behind the screen SK.
As a result, the space on the viewer side is 6 m. Screen
Since a recent viewing distance of about 3 m is required in front of the room, the viewer's seat will eventually be limited to 3 m, and the utilization rate of the room will decrease.

(2) In order to install a screen for a rear projection device, it is usually necessary to install a partition such as a wall in the screen to separate the room and to make the rear of the screen a dark room. there were.

Due to the above problems associated with the rear projection device, a bright front projection device has been desired. FIG. 14 is a performance comparison and contrast diagram of a large projection device. In FIG. 14, a large rear projection device according to the conventional method, a large front projection device according to the conventional method, and a large front surface according to the present invention are shown. A performance comparison between the projector and the projection device is made by taking a color shift of about 3 dB at ± 35 ° from the center as an example.

As can be seen from the performance comparison chart of FIG. 14, in order to obtain the same color shift in the same suitable viewing range, the conventional front projection apparatus has a screen screen compared to the rear projection apparatus.
Gain should be halved. This means that the brightness of the screen in the front projection type device is only half that of the rear projection type device, indicating that the utilization efficiency of the light quantity is poor.

Some front projection devices have a spherical spherical surface to improve the utilization efficiency of the amount of light and obtain a bright screen, but the horizontal suitable viewing range and color shift are inferior to those of the rear projection device. Above, a large screen over 120 "
There was a problem that it was difficult to manufacture a computer.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide a front projection device which, unlike a rear projection device, requires a small space behind the screen, and eliminates the above-mentioned drawbacks of the front projection device. By reducing the color shift and obtaining a wide horizontal viewing range, the light scattered outward is directed to the viewer side to reduce the loss of the light amount and to increase the screen gain.
It is to provide a bright front projection device that is as bright as a rear projection device.

[0015]

In order to achieve the above object, the present invention has, as its basic structure, a microscopic device for horizontal diffusion on the incident surface of a transparent lenticular sheet provided on a screen surface. A lenticular lens is formed, and a reflective surface is formed on the back side of the sheet opposite to the incident surface.

A light beam projected on the screen from a projection lens in front of the screen is incident on a lenticular lens formed on the incident surface of the lenticular sheet on the screen surface and is refracted and transmitted. The sheet is reflected by the reflecting surface formed on the back side of the sheet, returns, passes through the lenticular sheet again, and is diffused and emitted from the lens surface of the lenticular lens to the viewer side.

Here, as the lenticular lens, a convex circular or aspherical lenticular lens having a light converging property on the surface of the screen is used, and the rear side of the lenticular sheet. The position of the reflecting surface formed on the lenticular lens is at a position approximately half the focal length of the lenticular lens, the reflecting surface is a flat surface or a wavy inclined surface, and the reflecting surface is substantially A black stripe band or a light absorption band in a region where effective light does not exist, that a dye or a slight diffusing material is mixed in the lenticular sheet as the case may be, and a lenticular lens having the same light beam. Passing through the surface twice plays an important role in achieving the above object, and is a main feature of the present invention.

[0018]

A light beam projected onto the screen from the projection lens in front of the screen is incident on the lenticular lens formed on the incident surface of the lenticular sheet on the screen surface and then the lens. After passing through the lenticular sheet, the light is reflected by the reflecting surface formed on the back side of the lenticular sheet, and then returns to the vicinity of the front and back of the lenticular lens surface in a converged state. As a result, the diffused light is emitted from the lenticular lens surface to the viewer side in a wide suitable viewing range, and the functions of correcting the color shift and correcting the direction of the light emitted from the periphery of the screen to the observer side are realized. ..

When the inclination of the reflecting surface is changed, the direction of the emitted light ray can be freely selected. The black stripes or the light absorption bands serve to eliminate the reflection of extraneous light and stray light and improve the contrast of the screen display image. When a dye or a diffusing agent is mixed in the lenticular sheet, they improve the color saturation, the contrast, or adjust the diffusing property.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a top view showing an outline of an optical system as a main part of one embodiment of the present invention. In the figure, 1 is a CRT
(Cathode ray tube) 2, a projection lens for projecting an image displayed on a CRT, and 3 a transparent lenticular sheet. On the incident surface of the projection light of the lenticular sheet 3,
A horizontal diffusion lenticular lens 5 is formed.

Reference numeral 6 denotes a reflecting surface, which is formed on the back side of the lenticular sheet 3 opposite to the incident surface. Reference numeral 7 denotes a black stripe band (black stripe), which is provided on the back surface side in a region where effective light does not substantially exist along the arrangement direction of the lenticular lenses 5. 8 is a lenticular
It is a reinforcing plate which is on the back side of the sheet 3 and supports the sheet 3. The reflective surface 6 is not limited to the back surface of the lenticular sheet 3, but may be formed on the surface of the reinforcing plate 8 in contact with the back surface. In this case, the reinforcing plate 8 is brought as close as possible to the lenticular sheet 3.

The light beam projected from the CRT 1 is enlarged and projected by the projection lens 2, enters the lenticular lens 5 on the surface of the lenticular sheet 3, passes through the lenticular lens 5, is reflected by the reflecting surface 6, and returns. The light passes through the lenticular sheet 3 again and is enlarged and emitted from the lens surface of the lenticular lens 5 to the viewer side.

When the reflecting surface 6 is formed by vapor deposition of aluminum or silver, it has a high reflectance. Also, a good reflecting surface can be obtained by pasting an aluminum foil or applying a reflective paint containing aluminum as a main component. The black stripe band 7 may be painted black so as not to reflect it, or may be formed of a member that absorbs light so as not to reflect it. When the black stripe band 7 is printed on the surface farther from the incident surface of the lenticular sheet 3, that is, on the back surface of the sheet 3, the positional deviation from the lenticular lens 5 is reduced and the light is blocked. This is advantageous because there is no loss due to.

The lenticular lens 5 is made of a transparent synthetic resin and has a convex circular shape having a converging property or an elliptic aspherical surface extended in the optical axis direction. FIG. 2 shows an enlarged view of the basic shape of the lenticular lens 5 when it has an elliptical shape. In other words, FIG. 2 is an enlarged side view of the lenticular lens 5. As can be seen in the figure, when the X and Y coordinates are taken and the refractive index of the synthetic resin forming the lens is n, if the eccentricity e of the ellipse forming the lens surface is equal to 1 / n, the elliptical shape is obtained. Is the following formula (1)
Is established.

X ² + Y ² / [1- (1 / n) ² ] = 1 (1)

All the elliptical lenses represented by the above formula (1) are shown in FIG. 2 when light enters parallel to the major axis of the ellipse.
As shown by, the focal point F is located farther from the incident surface. The lenticular sheet 3 is mainly composed of an acrylic material, and its refractive index n is about 1.5. Assuming now that the thickness of the lenticular sheet 3 is (1 + 1 /
n), the parallel incident light is diffused and emitted from the focal point F.

In the embodiment of the present invention, as shown in FIG. 2, the thickness of the lenticular sheet 3 is approximately (1 + 1).
/ N) / 2 and a reflecting surface 6 is provided on the back side far from the incident surface, the light incident in parallel to the lenticular lens 5 passes through the inside of the lenticular sheet 3 and is directed to the focal point F. Then, the light is reflected by the reflecting surface 6, passes through the inside of the lenticular sheet 3 again, and returns to the lenticular sheet.
It converges in the vicinity of the lens surface of the lens 5 (in the vicinity of the front-back direction), and diffuses and emits from the lenticular lens 5 in the horizontal direction toward the viewer.

As shown in FIG. 2, the black stripe band 7 is provided in an area where effective light does not exist between adjacent lenticular lenses 5. The black stripe band 7 prevents external light and back light from reflecting and returning, so that the contrast can be improved. A transparent synthetic resin forming the lenticular sheet 3 is mixed with a dye or a slight amount of a diffusing material to improve the color saturation and contrast, or adjust the diffusing property.

If the thickness of the lenticular sheet 3 is increased, the horizontal luminance half-value angle (the angle at which the horizontal luminance decreases from its maximum value to half) becomes narrower and the screen gain increases. Further, if the thickness is made thinner, the horizontal luminance half-value angle widens and the screen gain lowers. Therefore, the thickness is set to about 1/3 of (1 + 1 / n) according to the condition of the viewer seat.
Select within ~ 2/3.

By the way, the projection light rays from the lens 2 are obliquely incident on the left and right ends of the lenticular sheet 5 shown in FIG. FIG. 3 is an enlarged view showing an optical path when a light ray is obliquely incident on the elliptical lenticular lens 5. As shown in FIG. 3, when the thickness of the lenticular sheet 5 is (1 + 1 / n) / 2, the light rays obliquely incident on the elliptical lenticular lens 5 are lenticular sheet 5. After passing through 3, the light is reflected by the reflection surface 6, passes through the lenticular sheet 3 again, and reaches the elliptical outer oblique surface of the lenticular lens 5.

A light ray emitted from the oblique surface is emitted toward the viewer because the optical path is corrected in the optical axis direction by Snell's law. The conventional screen shown in FIG.
In FIG. 1 to FIG. 3, which shows the embodiment of the present invention, the optical axis reflected light 4 is directed toward the viewer side. The light is corrected and emitted in a direction substantially parallel to the optical axis of the lenticular lens 5 so as to be bent. This function is not present in the conventional front projection screen and is a major feature of the present invention.

As shown in the embodiment of the present invention in FIG. 1, by correcting the reflected light 4 on the optical axis to the viewer side, the horizontal suitable viewing range can be widened and the color shift can be reduced. Can be made For example, in the prior art, FIG.
4 and FIG. 13, the horizontal luminance 1/4 angle is 65 °
At this time, the horizontal suitable viewing range is 90 ° PP (peak-to-peak).

On the other hand, in the embodiment of the present invention, as shown in FIG. 1, although the horizontal luminance ¼ angle is as small as 45 °, the horizontal suitable viewing range can be as wide as 90 ° PP. This means that the light scattered to the outside is condensed and the amount of light is effectively used. Further, since the horizontal luminance 1/4 angle can be narrowed, the amount of light traveling forward is increased, the screen gain can be increased, and a bright image can be obtained.

The screen gain is expressed by the following equation (2). G = B · π / I (2) (G: screen gain, I: screen incident illuminance,
B: Screen emission brightness)

Regarding the principle of obtaining the directional characteristics of the emitted light and the low color shift of the elliptical lenticular lens shown in the embodiment of the present invention, when it is used in a rear projection device, Japanese Patent Laid-Open No. 59-59436. The detailed description is omitted here.

FIG. 4 is a top view showing the outline of an optical system as a main part of another embodiment of the present invention. In the figure, 9
Indicates a sawtooth-shaped wave-reflecting surface, and each sawtooth is provided on the back surface of the lenticular sheet 3 farther from the incident surface so as to correspond to the individual lenticular lens 5. FIG. 5 is an enlarged view showing a sawtooth waveform reflecting surface. Reference numeral 10 in FIG. 5 is a rising portion of the sawtooth waveform and shows a black stripe band provided in a region where effective light does not substantially exist. It prevents the reflection of external light and stray light.

In the embodiment shown in FIG. 4, a state in which a light beam obliquely enters the end of the lenticular sheet 3 can be seen in the enlarged view of FIG. In FIG. 5, the ray of light is bent in the direction of the incident ray and is reflected by the sawtooth wave-shaped reflecting surface 9, so that the optical axis reflected light 4 emitted from the lenticular lens 5 is directed toward the center side of the viewer's seat. Emit. As a result, as shown in the embodiment of FIG. 4, the horizontal suitable viewing range can be expanded to 110 ° although the horizontal luminance ¼ angle is 45 °, which is the same as in FIG.

FIG. 6 is an enlarged view showing another example of the sawtooth wave-shaped reflecting surface in FIG. As shown in FIG. 6, the saw-toothed corrugated reflection surface 9 may be provided on the front surface side of the reinforcing plate 8 instead of the back surface side of the lenticular sheet 3. In this case, the reinforcing plate 8 can function almost as in the case of FIG. 5 by bringing the reinforcing plate 8 as close as possible to the lenticular sheet 3.

FIG. 7 is a side view of an embodiment of the present invention.
That is, FIG. 7 is a side view of the front projection device when the lenticular lens 5 is arranged for horizontal diffusion as described with reference to FIGS. In FIG. 7, the lenticular
The sheet 3 is arranged so as to be bent in a concave shape in a vertical direction (obliquely upward direction) in an arc shape. By bending it in an arc shape in the vertical direction (obliquely upward direction), a wide vertical suitable viewing range can be obtained even if the vertical luminance ¼ angle is small.

In the prior art, for example, as shown in FIG. 8 showing a conventional rear projection device, since the screen SK is flat in the rear projection type, when the vertical luminance 1/4 angle is 15 °, the vertical projection is vertical. The viewing range is 30 °. On the other hand, in the embodiment of the present invention, as shown in FIG.
Despite the narrow angle of 10 °, the vertical viewing range is 32
Widely obtained with °. Since the vertical luminance 1/4 angle can be narrowed, diffusion loss to the outside is reduced, the amount of light traveling forward is increased, and the screen gain can be increased. This means that the amount of light is effectively used, and a bright image can be obtained.

As described above, in the present invention, the optical axis reflected light 4 can be corrected to the viewer side in both the horizontal direction and the vertical direction as compared with the conventional projection apparatus. This plays an important role in obtaining a bright screen and is the aim of the present invention.

In general, the following equation (3) is commonly used as a means of expressing the efficiency of light quantity utilization of the screen. F · M = αH × αV × Go (3) However, F · M: Figure Merit, αH: horizontal luminance ½ angle, αV: vertical luminance ½ angle, Go: screen center gain.

When a lenticular lens is used in the horizontal diffusion system, FM is 1400 or more (data value αH = from the actually measured data of the rear projection apparatus shown in FIG. 12 of the conventional example).
40 °, αV = 6.5 °, Go = 5.6 ° or more). In the formula (3), when the same diffusion method is used, FM is almost constant.

Since the front projection device of the present invention employs the lenticular lens in the horizontal diffusion system, the F · M is 140
It is possible to obtain about 0. According to the front projection apparatus of the present invention, αH = 40 ° and αV = 5 °, and G from Equation (3)
o = FM / (αH × αV) = 1400 / (40 × 5) =
7, the screen center gain Go of the front projection apparatus of the present invention is almost 7.

On the other hand, the screen center gain Go of the conventional front projection device shown in FIG. 13 is about 2.8 from the measured data. From this data, the screen center gain of the front projection apparatus of the present invention is 2.5 times. This means that the screen brightness has increased 2.5 times.

FIG. 14 is a summary of the performance comparison between the front projection apparatus of the present invention and the conventional large-sized projection apparatus having a size exceeding 120 ″ based on the above results. Please refer to the above embodiments. The shape of the lenticular lens 5 has been described as an elliptical shape, but if it is convex and convergent, it can be made into a circular shape or an aspherical shape according to the purpose to select the optimum viewing range.

FIG. 9 is a schematic side view of an optical system according to another embodiment of the present invention, and FIG. 10 is a top view of the same. In these figures, 15 is a vertical lenticular lens, and 16 is a reflecting surface in the same arrangement as the vertical lenticular lens 15. 13 is a lenticular sheet, which is a plane in the vertical direction,
It is arranged in a concave bow shape in the horizontal direction. This method is suitable for use in a special place such as a display in front of a stairway or a passage because the quarter-luminance can be wide in the vertical direction and narrow in the horizontal direction.

FIG. 11 is a schematic external view showing the main part of another embodiment of the present invention. In the figure, the lenticular lens 5 for horizontal diffusion is provided on the incident surface of the lenticular sheet 3.
And a reinforcing plate 8 provided side by side or on the back side farther from the incident surface.
A reflecting surface 6 is provided on the surface of the above so as to be orthogonal to the arrangement direction of the lenticular lenses 5. The reflecting surface 6 is formed of a plurality of microscopic polyhedral wavefronts that separate the outgoing direction of the reflected light beam into two or more directions.

For example, when the auditorium is on the first floor and the control room is on the second floor, and when it is desired to set the emitted light amounts to 80% and 20%, respectively, the reflecting surface toward the first floor and the reflecting surface toward the second floor can be adjusted. This can be easily achieved by setting the area ratio to 4: 1. When the projection device is installed on the second floor and the emitted light is to be directed to the lobby on the first floor, the sawtooth wavefront is formed so that the reflection surface 6 faces almost downward. Also, the vertical diffusion angle can be widened by making the surface multifaceted (including the circular surface).

[0050]

As described above, according to the present invention,
Overcoming the shortcomings of the rear projection device and the front projection device of the conventional technology, with a small color shift, and obtaining a wide viewing range, it is possible to obtain a high screen gain. Even brighter (about 2.5 times)
You can enjoy the images.

In addition, the direction of light emission can be freely selected up, down, left, or right according to the purpose, and in the past, where a rear projection device was unavoidably installed in a small room, the brightness was emphasized.
The front projection device according to the present invention, which has a small space behind the screen, can be installed, and in that sense, a great effect can be obtained.

[0052]

[Brief description of drawings]

FIG. 1 is a top view showing an outline of an optical system as a main part of an embodiment of the present invention.

FIG. 2 is an enlarged side view of the lenticular lens shown in FIG.

3 is an enlarged side view showing a case where the lenticular lens in FIG. 1 is obliquely incident.

FIG. 4 is a top view showing the outline of an optical system as a main part of another embodiment of the present invention.

5 is an enlarged view showing a sawtooth wave-shaped reflecting surface formed on the back surface of the lenticular sheet in FIG.

6 is an enlarged view showing a sawtooth wave-shaped reflection surface formed on the surface of the reinforcing plate in FIG.

FIG. 7 is a side view showing a front projection device according to an embodiment of the present invention.

FIG. 8 is a schematic side view showing a conventional example of a rear projection device.

FIG. 9 is a schematic side view of an optical system according to another embodiment of the present invention.

FIG. 10 is a schematic top view of the optical system of the example shown in FIG.

FIG. 11 is a schematic top view of an optical system showing another embodiment of the present invention.

FIG. 12 is a schematic top view showing an optical system of a conventional lenticular-lens diffusion type rear projection device.

FIG. 13 is a top view showing an outline of an optical system of a diffused reflection type front projection device according to a conventional technique.

FIG. 14 is a comparative performance chart of a large projection device.

[Explanation of symbols]

1 ... CRT, 2 ... Projection lens, 3 ... Lenticular series
G, 4 ... Optical axis reflected light, 5 ... Lenticular lens, 6 ...
Reflective surface, 7 ... Black stripe band, 8 ... Reinforcing plate, 9 ... Sawtooth waveform reflective surface, 10 ... Non-reflective portion of rising portion

Claims (10)

[Claims] 1. A projection lens is arranged on the front surface of a diffuse reflection screen, and the projection lens is inserted through the projection lens with respect to the diffusion reflection screen located at the convergence plane position of the projection light projected through the projection lens. In the front projection device configured to project an image by using the lenticular sheet, the screen includes a lenticular sheet disposed on a light receiving surface of the projection light from the projection lens, and each profile of the plurality of lenticular lenses forming the lenticular sheet. Is an aspherical shape such as a circular shape or an ellipse, and the thickness dimension of the lenticular lens in the light incident direction is 1/3 to 2/3 of the focal length of the lens, and the light incident surface of the lenticular sheet is A reflecting surface is formed on the back side opposite to the side, and the light rays projected through the projection lens are the lenticular lens surface. After entering, refracting and passing, and by being reflected by the reflecting surface, again returns to the vicinity of the front and rear of the lenticular lens surface in a convergent state, and diffuses and emits from there to the viewer side in front. A front projection device. 2. The front projection device according to claim 1, wherein the lenticular lens is a lens made of transparent synthetic resin, and the reflecting surface is vapor-deposited with aluminum or silver.
Alternatively, the front projection device is characterized in that the front projection device is formed by applying a reflective paint or adhering an aluminum foil. 3. The front projection device according to claim 1, wherein when the profile of the lenticular lens has an aspherical shape such as an ellipse, the eccentricity of the aspherical surface is substantially equal to the reciprocal of the refractive index n of the lens medium. The front projection device is characterized in that the color shift of the screen on the screen is reduced by doing so. 4. The front projection device according to claim 1, wherein the reflecting surface is formed in a sawtooth shape by repeating a sawtooth waveform in a cross section at the same bitch in accordance with the arrangement direction of the lenticular lenses. A front projection device comprising a wavefront, wherein light reflected from the sawtooth wavefront is directed to a front viewer side. 5. The front projection device according to claim 1, wherein the reflection surface is composed of a set of inclined surfaces having a mountain-shaped cross section extending in a direction orthogonal to the arrangement direction of the lenticular lenses, and reflected from the reflection surface. A front projection device, characterized in that the rays of light separated are directed in at least two directions. 6. The front projection device according to claim 1, wherein a lenticular sheet is provided on a rear surface side opposite to a light incident surface side, along a lenticular lens arrangement direction.
A front projection device characterized in that a black stripe band is provided in a region where effective light does not substantially exist to improve the contrast in a screen viewed from a viewer side. 7. The front projection device according to claim 4, wherein the rising portion of the saw-tooth waveform is provided in a region in which effective light does not substantially exist along the arrangement direction of the lenticular lens. By providing a black stripe band that does not reflect light or an absorption band that absorbs light in the rising portion,
A front projection device, characterized in that the contrast of a screen viewed from a viewer side is improved. 8. The front projection device according to claim 2, wherein the transparent synthetic resin forming the lenticular lens is mixed with a dye or a diffusing agent to improve color saturation and contrast, or to diffuse characteristics. A front projection device characterized in that 9. The front projection device according to claim 1, wherein the screen is a screen that is curved in a concave arc shape in the vertical direction and is flat in the horizontal direction. A front projection device characterized in that 10. The front projection device according to claim 1, wherein the screen comprises a screen having a concave bow shape in the horizontal direction and a flat shape in the vertical direction. A front projection device characterized in that