JP3407764B2 - Transmission screen - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a transmissive screen.

[0002]

2. Description of the Related Art In a projection type image display device for enlarging and projecting an image such as a television image on a screen, an image formed by an image forming means such as a CRT or a liquid crystal display device is enlarged and projected on a screen by a projection optical system. By
There is an image forming device that has a small screen size and is capable of obtaining a large-screen image.

FIG. 6 is a schematic configuration diagram showing an example thereof. In this projection type image display device, an image is created by a projector unit 2 as an image projecting means provided in the device body 1, and this image is displayed on the front surface (left surface in the figure) of the device body 1 by a total reflection mirror 3. The image is enlarged and projected on the transmission screen 4 provided. In this case, the projector unit 2 includes an image forming means such as a CRT or a liquid crystal display device, a projection lens for projecting an image formed by the image forming means, and the like. The total reflection mirror 3 is
The light of the image from the projector unit 2 is reflected toward the transmissive screen 4.

On the transmissive screen 4 of such a projection type image display device, when the image is viewed, the height of the eyes is almost the same, but the positions in the left and right directions are different each time, so the image light is directed in the left and right directions. Need to spread. Therefore, the conventional transmissive screen 4 is, as shown in FIGS. 7 and 8,
A Fresnel lens 5 that collects the light reflected by the total reflection mirror 3 into parallel light, and a lenticular plate 6 that diffuses the light incident as parallel light from the Fresnel lens 5 in the left-right direction,
It is composed of an adhesive 7 for joining the Fresnel lens 5 and the lenticular plate 6. In order to diffuse the light in the left-right direction, the lenticular plate 6 has line-shaped lens portions 8 arrayed in the left-right direction on the exit surface as shown in FIG. It has a structure in which a diffusing agent is mixed in order to diffuse the light.

[0005]

However, in such a transmissive screen 4, since light can be largely diffused in the left-right direction by the lens portion 8 formed on the emission surface of the lenticular plate 6, the light in the left-right direction can be diffused. Although the viewing angle greatly expands, the vertical viewing angle only slightly expands due to the diffusion effect of the diffusing agent mixed in the lenticular plate 6, so that there is a problem that the vertical viewing angle is narrower than the horizontal viewing angle. . The present invention has been made in view of the above circumstances, and an object thereof is to provide a transmissive screen that can widen the viewing angle in the vertical direction as well as in the horizontal direction.

[0006]

The invention according to claim 1 is
The light incident from one surface is parallel to the screen surface
The Fresnel lens that turns the light into
Lenticular plate that diffuses the emitted parallel light to the left and right
And joining the Fresnel lens and the lenticular plate
Lined adhesive parts are arranged at regular intervals in the vertical direction
And the upper and lower end faces are concave or convex, respectively.
And an adhesive layer formed on
Of.

[0007]

According to the first aspect of the invention, the light emitted from the Fresnel lens can be diffused in the left-right direction by the lenticular plate, and at the same time, the linear adhesive portions arranged in the vertical direction at regular intervals are formed. the respective ends of the upper and lower can be diffused in the vertical direction, thereby the left-right direction, of course, can be expanded also the viewing angle in the vertical direction
become.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the transmissive screen of the present invention will be described below with reference to FIGS. In addition,
The same parts as those in the conventional example shown in FIGS. 6 to 8 are designated by the same reference numerals, and the description thereof will be omitted. The transmissive screen 10 shown in FIGS. 1 and 2 has a structure in which the Fresnel lens 5 and the lenticular plate 6 are joined by an adhesive layer 11.
The adhesive layer 11 has a structure in which line-shaped adhesive portions 12 are formed in horizontal stripes arranged in the vertical direction at regular intervals in FIG. 1, and each upper and lower end surface of each adhesive portion 12, that is, the adhesive portion 12 The boundary surface between the air and the air 13 is formed as a concave surface 14 as shown in FIG. In this case, the shape of the concave surface 14 is determined by the viscosity and refractive index of the adhesive, the amount and width and pitch of the adhesive, and the distance between the Fresnel lens 5 and the lenticular plate 6. Further, in this embodiment, the Fresnel lens 5 and the lenticular plate 6 are set to have a larger refractive index than the air 13 and the adhesive portion 13 is set to have a larger refractive index than the Fresnel lens 5 and the lenticular plate 6. There is. The Fresnel lens 5 and the lenticular plate 6 have the same or almost the same refractive index.

In such a transmissive screen 10, the light incident on the Fresnel lens 5 is collimated by the Fresnel lens 5 so as to be parallel light La to Ld perpendicular to the transmissive screen 10.
As a result, the lights La to Ld enter the adhesive layer 11 as shown in FIG. At this time, of the light rays La and Lb that reach the concave surface 14 on the upper end side of the adhesive portion 12, the upper light ray La is incident on the adhesive portion 12 and enters the concave surface 1 of the adhesive portion 12.
After being totally reflected obliquely downward at 4, and refracted at the facing concave surface 14, it is incident on the lenticular plate 6 at an angle, is refracted at this lenticular plate 6, and is obliquely downward and leftward and rightward from the lens portion 8. It will be emitted. Similarly, the light ray Lb is incident on the adhesive portion 12 and is totally reflected obliquely downward on the concave surface 14 of the adhesive portion 12, and thereafter is incident on the lenticular plate 6 at an angle, is refracted by the lenticular plate 6, and is refracted by the lens. The light will be emitted obliquely downward and leftward and rightward from the portion 8. The adhesive portion 12
Rays reaching the concave surface 14 on the lower end side of the (see FIG. 2 (b))
Is emitted from the lenticular plate 6 obliquely upward and leftward and rightward through an optical path that is vertically symmetrical with the light rays La and Lb. Further, the light rays Lc and Ld that do not reach the concave surface 14 of the adhesive portion 12 are shown in FIGS.
As shown in FIG. 5, the light is emitted straight as it is and is emitted in the left-right direction by the lens portion 8 of the lenticular plate 6.

As described above, in the transmissive screen 10, the light emitted from the Fresnel lens 5 is converted into the light shown in FIG.
As shown in FIG. 2B, the lenticular plate 6 can diffuse in the left-right direction, and as shown in FIG. 2B, the concave surfaces 14 of the adhesive portion 12 can diffuse in the vertical direction. That is, the viewing angle can be expanded in the vertical direction. In this case, in particular, since the upper and lower ends of the adhesive portion 12 are formed in the concave surface 14, the diffusion region becomes wider than that of the flat surface of the upper and lower ends, the diffusion effect is improved, and the one having extremely good viewing angle characteristics is selected. Obtainable.

In the above embodiment, the upper and lower end surfaces of each adhesive portion 12 are formed as concave surfaces 14, but the present invention is not limited to this, and they may be formed as convex surfaces or inclined surfaces. Even in this case, the same effect as that of the first embodiment can be obtained.

Next, a second embodiment of the transmissive screen of the present invention will be described with reference to FIGS. 4 and 5.
Also in this case, the same parts as those of the conventional example shown in FIGS. 6 to 8 are designated by the same reference numerals, and the description thereof will be omitted. The transmissive screen 20 shown in FIGS. 4 and 5 includes a Fresnel lens 5 and a lenticular plate 21. Similar to the conventional example, the lenticular plate 21 has a structure in which a diffusing agent is mixed and line-shaped lens portions 8 for diffusing light in the left-right direction are arrayed and formed on the emitting surface in the left-right direction at regular intervals. . Then, on the incident surface of the lenticular plate 21,
As shown in FIG. 5B, the line-shaped refraction portions 22 are arranged in the vertical direction at regular intervals. Each line-shaped refraction part 22 is made of a synthetic resin having a higher refractive index than the lenticular plate 21, and is formed in a substantially semi-circular cross section that is convex toward the emission side.

In such a transmissive screen 20, when light is incident from the Fresnel lens 5 as parallel light perpendicular to the incident surface of the lenticular plate 21, of the incident light, the light incident on the linear refracting portion 22. As shown in FIG. 5B, the refraction section 22 refracts the upper half downward and the lower half upward, and the light is emitted from the lens portion 8 of the lenticular plate 6 in the vertical direction and the horizontal direction, and The light incident between the refracting portions 22 proceeds straight as it is and is emitted from the lens portion 8 of the lenticular plate 6 in the left-right direction. As described above, in the transmissive screen 20, the light emitted from the Fresnel lens 5 is emitted as shown in FIG.
As shown in FIG. 5, it can be diffused in the left-right direction by the lenticular plate 21, and can be diffused in the vertical direction by the respective refraction portions 22 of the lenticular plate 21 as shown in FIG. Therefore, the viewing angle can be expanded in the vertical direction, and a device having good viewing angle characteristics can be obtained.

In the second embodiment described above, the line-shaped refracting portion 22 is formed in a semi-circular cross section, but the invention is not limited to this.
It may be formed in a polygonal shape such as a triangular shape or a trapezoidal shape. Further, in the second embodiment, the line-shaped refracting portion 22 is formed of a synthetic resin having a refractive index higher than that of the lenticular plate 21. It may be formed of resin. Further, in the second embodiment described above, the linear refraction portion 22 is provided on the incident surface of the lenticular plate 21, but the lenticular plate 2 is not always necessary.
It is not necessary that the number is 1, and line-shaped refracting portions may be arrayed and formed on the exit surface of the Fresnel lens 5 while being vertically separated by a predetermined distance.

[0015]

As described above, according to the first aspect of the present invention, the light emitted from the Fresnel lens can be diffused in the left-right direction by the lenticular plate, and the light can be vertically spaced by a certain distance. The upper and lower ends of the line-shaped adhesive portions formed in an array can be diffused in the vertical direction as well, so that not only the horizontal direction but also the vertical viewing angle can be expanded .

[Brief description of drawings]

FIG. 1 is an external perspective view of a transmissive screen according to a first embodiment of the present invention.

2A is an enlarged sectional view taken along line A ₁ -A ₁ of FIG. 1, and FIG. 2B is an enlarged sectional view taken along line A ₂ -A _{2 of} FIG.

FIG. 3 is a principle diagram showing a traveling state of light in FIG.

FIG. 4 is an external perspective view of a transmissive screen according to a second embodiment of the present invention.

5A is an enlarged sectional view taken along line B ₁ -B ₁ of FIG. 4, and FIG. 5B is an enlarged sectional view taken along line B ₂ -B _{2 of} FIG.

FIG. 6 is a schematic configuration diagram of an image projection device using a transmissive screen.

FIG. 7 is an external perspective view of a conventional transmissive screen.

8A is an enlarged sectional view taken along the line C ₁ -C ₁ of FIG. 7, and FIG. 8B is an enlarged sectional view taken along the line C ₂ -C ₂ of FIG. 7.

[Explanation of symbols]

5 Fresnel lens 6,21 Lenticular plate 8 lens part 10, 20 Transmissive screen 11 Adhesive layer 12 line-shaped adhesive 14 concave 22 Line-shaped refraction part

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03B 21/56-21/64 G02B 3/00

Claims (2)

(57) [Claims] 1. A Fresnel lens for converting light incident from one surface into parallel light perpendicular to a screen surface, a lenticular plate for diffusing the parallel light emitted from the Fresnel lens in the left-right direction, the Fresnel lens and the The line-shaped adhesive parts that join the lenticular plate are arranged at regular intervals in the vertical direction , and the upper and lower end surfaces are concave.
A transmissive screen comprising: an adhesive layer formed on a surface or a convex surface . 2. The transmissive screen according to claim 1, wherein a diffusing agent is mixed in the lenticular plate.