JP3682180B2 - Projection type screen - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projection type screen used for a rear projection type projection television.
[0002]
[Prior art]
There are two types of screens commonly used in liquid crystal rear projection televisions: a single-sided lenticular screen type with a tint and a double-sided lenticular screen type with a black stripe, each of which will be described below.
[0003]
An example of a single-sided lenticular screen type with Tint will be described.
[0004]
FIG. 9A is a top view of the rear projection type display device. Light having a certain angle is emitted from the projection lens 101, and this light is converted into parallel light by the Fresnel sheet 102 and incident on the single-sided lenticular 103. And diffused and emitted. Next, this light passes through a tint layer 106 and is emitted as light 104 having a certain viewing angle. This light is projected as an image to the user's eyes. FIG. 9B is a perspective view of the single-sided lenticular sheet 103, and FIG. 9C is a cross-sectional view of the single-sided lenticular sheet 103.
[0005]
The conventional single-sided lenticular sheet has a shape in which a convex (or kamaboko) lens is formed in the vertical direction (stripe shape) with respect to the user's eyes, as shown in a perspective view. The single-sided lenticular sheet is a resin layer in which a diffusing agent is mixed. When incident light of parallel light enters the convex lens portion, this light is diffused by the diffusing agent and is emitted as light having a certain viewing angle characteristic.
[0006]
Here, the convex lens controls the viewing angle characteristic in the horizontal direction, and the vertical viewing angle depends on the diffusion control by the diffusing agent.
[0007]
FIG. 10A is a top view of a double-sided lenticular screen type with black stripe.
[0008]
Light having a certain angle is emitted from the projection lens 101, and this light is converted into parallel light by the Fresnel sheet 102 and enters the double-sided lenticular sheet 120. On this sheet 120, light is diffused and is displayed in the eyes of the user as an image of light 104 having a certain viewing angle. FIG. 10B is a perspective view of the double-sided lenticular sheet 120, and FIG. 10C is a cross-sectional view. The black stripe part (light-shielding layer) 130 increases the contrast in the image by suppressing reflection of external light.
[0009]
The double-sided lenticular sheet 120 has convex lenses on both sides as shown in a perspective view, and this lens part is in the vertical direction (stripe shape) with respect to the user's eyes. A black stripe portion (light shielding layer) is formed between the lenses on the light exit surface. As shown in FIG. 10C, the cross-sectional structure includes a transparent oil / fat layer 117, a resin layer 118 containing a diffusing agent, and a black stripe portion (light-shielding layer) 130. Parallel light 116 enters the convex lens portion as incident light, is focused in the lenticular sheet 120, and is diffused by the resin layer 118 containing a diffusing agent of the convex lens on the exit side.
[0010]
Here, the convex lens on the incident side has a larger shape than the convex lens on the outgoing side, but this is provided with a black stripe (light-shielding layer) 130 for suppressing external light reflection on the outgoing side and at the same time improving the light efficiency. This is to obtain a function that does not deteriorate. The convex lenses on both sides control the viewing angle characteristics in the horizontal direction, and the viewing angle characteristics in the vertical direction depend on the resin layer 118 containing a diffusing agent.
[0011]
[Problems to be solved by the invention]
As described above, both the conventional single-sided lenticular screen and black stripe lenticular screen are formed in the vertical direction (stripe shape) when viewed from the user side, but this lens effect is only for horizontal viewing angle characteristics. It is not intended to control the viewing angle in the vertical direction. Therefore, the viewing angle in the vertical direction is controlled only by the diffusing agent, and the viewing angle is very narrow.
[0012]
In addition, as a problem unique to the single-sided lenticular screen, a Tint layer is formed to suppress reflection of external light, and the light transmission efficiency of outgoing light is deteriorated with respect to incident light.
[0013]
Accordingly, an object of the present invention is to provide a projection screen having a wide viewing angle, viewing angle control, high light transmission efficiency, high luminance, and high contrast (low external light reflectance).
[0014]
[Means for Solving the Problems]
According to the present invention, in a projection display device including a projection screen on which light is projected, a projection lens that receives light output from a light source and projects projection light toward the projection screen, and the projection lens A projection screen comprising an incident surface on which the projected light is incident, a reflecting mirror that receives and reflects the light incident on the incident surface, and an exit surface that emits the light reflected by the reflecting mirror; In the projection screen, the area of light incident on the incident surface is larger than the area of the exit surface, and the inner surface surrounding the space between the outer periphery of the entrance surface and the outer periphery of the exit surface is the reflecting mirror. The kaleidoscope is characterized in that a plurality of kaleidoscopes having different sizes are arranged and distributed on a plane.
[0015]
By providing the kalide screen, wide viewing angle characteristics, viewing angle control, and high brightness can be realized.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0017]
FIG. 1 is a diagram showing a schematic configuration of a projection screen 1 according to the first embodiment of the present invention.
[0018]
That is, the projection screen 1 includes a Fresnel screen 3 that changes the light emitted from the projection lens 2 into light that is nearly parallel to the optical axis, and the light that has passed through the Fresnel screen 4 is equal to or greater than its maximum incident angle. A kalide screen 4 that emits light having a divergent angle, a diffusing agent (diffusion member) 5 for displaying an image of the light emitted from the kaleido screen 4, and low external light reflection (high contrast) characteristics. It is comprised from the light shielding layer 6 for obtaining.
[0019]
In this specification, a screen configured by arranging a kaleidoscope described later is referred to as a kaleido screen. For example, a transparent synthetic resin is used as the material of the callide screen 4.
[0020]
FIG. 2 is a perspective view of the kaleido screen 4, and FIG. 3 is a diagram schematically showing one of the kaleidoscopes 7 included in the kaleido screen 4. As shown in FIG.
[0021]
That is, a plurality of kaleidoscopes (kaleidoscopes) 7 are embedded in the kaleido screen 4 in a planar shape. The kaleidoscope 7 has a quadrangle having an arbitrary aspect ratio as an incident surface 8, and a quadrangle having an area smaller than the incident surface 8 and an equal aspect ratio as an output surface 9. A space around the surface 9 is surrounded by a mirror (guide scope) 10, for example.
[0022]
As described above, the basis of this configuration is that the incident surface 8 has a large shape in any cross-sectional direction of the exit surface 9 and is formed from the vicinity of the outer periphery of the entrance surface 8 and the periphery of the exit surface 9. Mirrors 10a, 10b, 10c, and 10d, that is, a kaleidoscope 7 structure, which surrounds an arbitrary space to be reflected by a reflecting mirror. That is, the kaleidoscope 7 is constituted by the upper and lower mirrors 10a, 10b, 10c, and 10d.
[0023]
Therefore, the entrance surface 8 and the exit surface 9 of the plurality of kaleidoscopes 7 embedded in the kaleido screen 4 are opened.
[0024]
FIG. 4A is a view showing a perspective view of the kaleido screen 4 on which the light shielding layer 6 is formed, and a part thereof is taken out. FIG. 4B is a front view seen from the incident surface side of the kaleido screen 4, and FIG. 4C is a front view seen from the exit surface side of the kaleido screen 4.
[0025]
That is, the light shielding layer 6 is formed on the exit surface 9 side of the kaleido screen 4 in which a plurality of kaleidoscopes 7 are embedded. As shown in the drawing, the light shielding layer 6 is formed in a portion excluding the emission surfaces 9 (openings) of the plurality of kaleidoscopes 7. As shown in FIG. 1, a diffusion agent 5 for diffusing the light emitted from the emission surface 9 and displaying an image is provided in a portion corresponding to the emission surface 9 of the kaleidoscope 7 where the light shielding layer 6 is not formed. It is formed.
[0026]
As described above, a low external light reflection (high contrast) characteristic is obtained by forming the light shielding layer 6 on a portion other than the exit surface of the kaleido screen 4 in which a plurality of kaleidoscopes 7 are two-dimensionally arranged. Can provide a screen that does not bother with ambient light.
[0027]
Further, as described above, by forming the diffusing agent 5 only on the exit surface portion of the kaleido screen 4 in which a plurality of kaleidoscopes 7 are embedded, high light transmission efficiency and low external light reflection (high contrast). Characteristics can be obtained.
[0028]
Next, the necessity of the structure of the kaleido screen 4 in the projection screen of the present invention and the principle of construction will be described with reference to a vertical sectional view of the kaleidoscope 7 shown in FIG.
[0029]
That is, the size of the entrance surface 8 is “a”, the size of the exit surface 9 is “b”, the distance from the entrance surface 8 to the exit surface 9 is “d”, and the end of the exit surface 9 from the end of the entrance surface 8 is the mirror 10a, It shall be surrounded by 10b, 10c, 10d without a gap. Further, the intersection point on the extension line of the mirrors 10a and 10b is “O”, the distance from the incident surface 8 to the intersection point “O” is “L”, the optical axis angle of the mirrors 10a and 10b is “φ”, and the incident light is incident from the projection lens. When the incident angle of the light to the optical axis is “θt”, the number of times this light is reflected by the mirrors 10a and 10b is “n”, and the emission angle of the light emitted from the emission surface 9 is “θo”, The following formula is established.
[0030]
θo = θt + 2nφ (where θ o <90 degrees) (1)
φ = tan ⁻¹ {(ba) / 2d} (2)
L = d × b / (ba) (3)
For example, when light having a certain F value from the projection lens is incident on the optical axis at an angle of θt, it is reflected once on the mirror 10b and emitted from the exit surface 9 at an angle of θo as shown in the figure.
[0031]
At this time, from the above equation (1), θt <θo always holds. Therefore, the incident angle with respect to the optical axis of the incident light incident on the incident surface 8 of the kaleidoscope 7 having the above-described configuration is smaller than the outgoing angle with respect to the optical axis of the outgoing light exiting from the outgoing surface 9, that is, the outgoing angle. Becomes larger than the incident angle, the viewing angle in the vertical direction can be widened.
[0032]
The above description is based on FIG. 5 showing a vertical sectional view. However, since the horizontal sectional view is the same as FIG. 5, the horizontal viewing angle can be widened. .
[0033]
In addition, by appropriately setting a, b, d, and φ, the viewing angle in the horizontal direction and the vertical direction can be controlled.
[0034]
That is, the above-described kaleido screen 4 can obtain wide viewing angle characteristics in the horizontal direction and the vertical direction. Further, the viewing angle in the horizontal direction and the vertical direction can be controlled by changing the shape of the kaleidoscope 7 included in the kaleido screen 4.
[0035]
Further, since the relationship between the size “a” of the incident surface 8 and the size “b” of the exit surface 9 is a> b, the exit surface 9 exits without reducing the aperture ratio of the entrance surface 8 and the exit surface 9. A light shielding layer for producing a low external light reflection (high contrast) effect can be formed.
[0036]
Next, a description will be given with reference to a cross-sectional view of the kaleidoscope 7 shown in FIG.
[0037]
For example, as shown in FIG. 6, light having a certain F value from the projection lens enters the M point and the R point at incident angles of θt and θ′t (θt = θ′t) with respect to the optical axis, respectively. think of.
[0038]
Incident light that has entered the point M is reflected by the mirror once and emitted at an exit angle of θo with respect to the optical axis. On the other hand, the incident light incident on the point R is reflected twice and is emitted at an exit angle of θ′t with respect to the optical axis. At this time, the relationship between θo and θ′o is θo <θ′o.
[0039]
Therefore, the light incident on the incident surface from the projection lens with an equal F value has the light incident on the end of the mirror (incident light on the R point) at the maximum exit surface angle. As for this maximum angle, the maximum emission angle θo is determined by the incident angle θt and a, b, d, and φ.
[0040]
The kaleidoscope 7 sets a, b, d, and φ so that θ′o <90 degrees.
[0041]
Since the relationship between the size “a” of the incident surface 8 of the kaleidoscope 7 and the size “b” of the exit surface 9 is a> b, high brightness can be obtained by using the kaleido screen 4. Can do.
[0042]
In the present embodiment, the entrance surface 8 and the exit surface 9 of the kaleidoscope 7 are quadrangles having the same aspect ratio. For example, the entrance surface and the exit surface are square (the entrance surface and the exit surface are similar). The horizontal and vertical maximum viewing angles are the same under the condition that the incident angle is the same in all the incident planes.
[0043]
Here, similarly to the above, under the condition that the incident angle is the same in all the incident surfaces, d is the same, a, b, and φ are changed, and the incident surface and the output surface are not similar (non-similar shape). ), The emission angle is different between the horizontal and vertical angles.
[0044]
Therefore, the horizontal viewing angle difference and the vertical viewing angle difference can be controlled by making the entrance surface and the exit surface not similar, or by appropriately setting a, b, d, and φ.
[0045]
In addition, by appropriately distributing the kaleidoscopes 7 of different sizes and shapes in the kaleidoscreen 4, the horizontal viewing angle difference and the vertical viewing angle difference can be controlled more finely, and the light quantity is uniform. Can be controlled.
[0046]
In the first embodiment, the diffusing agent 5 is formed only on the exit surface 9 of the kaleidoscope 7. However, as shown in FIG. Even if it is formed as 5a, it can be similarly implemented.
[0047]
Moreover, in the said 1st Embodiment, although the shape of the entrance plane 8 and the exit surface 9 of the kaleidoscope 7 is made into the square, in order to obtain the most effective viewing angle light distribution characteristic, as shown in FIG. Furthermore, the present invention can be similarly applied to a hexagonal, rhombus-shaped arrangement, or any combination arrangement. According to this embodiment, the viewing angle characteristic can be controlled more finely.
[0048]
FIG. 8A shows an example in which a kaleidoscope 7A having a hexagonal entrance surface and an exit surface is two-dimensionally arranged. FIG. 8B shows two kaleidoscopes 7B having a diamond entrance surface and an exit surface. FIG. 8C shows an example in which a hexagonal kaleidoscope 7A and a rhombus kaleidoscope 7B are two-dimensionally arranged.
[0049]
Further, the viewing angle characteristics can be made finer by appropriately distributing the kaleidoscopes 7 having different sizes and shapes in the kaleidoscreen 4 and appropriately combining the arrangements of the kaleidoscopes 7 having different sizes and shapes. It can be controlled, and the uniformity of the light quantity can be controlled.
[0050]
In the above embodiment, the light shielding layer 5 is formed. However, if the material of the kaleido screen 4 is black or non-translucent material, it is not necessary to form the light shielding layer.
[0051]
Next, an example of a method for manufacturing a callide screen will be described. The synthetic resin sheet is subjected to, for example, pressing or etching to form a plurality of holes in the shape of the kaleidoscope 7 described above. And a mirror shall be formed by vapor-depositing aluminum etc. on each inner surface.
[0052]
【The invention's effect】
As described above in detail, according to the present invention, wide viewing angle characteristics, viewing angle control, high brightness, high light transmission efficiency, and high contrast (low external light reflectance) can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic view of a projection screen according to an embodiment of the present invention.
FIG. 2 is a perspective view of a kaleido screen constituting a projection screen.
FIG. 3 is a schematic diagram of a kaleidoscope.
FIG. 4 is a perspective view of a kaleido screen on which a light shielding layer is formed, and a diagram showing an incident surface side and an outgoing surface side of the kaleido screen on which a light shielding layer is formed.
FIG. 5 is a cross-sectional view of a kaleidoscope.
FIG. 6 is a sectional view of the kaleidoscope.
FIG. 7 is a schematic view of a projection screen according to another embodiment of the present invention.
FIG. 8 is a view showing another embodiment of a callide screen according to the projection type screen of the present invention.
FIG. 9 is a schematic view of a conventional projection screen.
FIG. 10 is a schematic view of a conventional projection screen.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 3 ... Fresnel screen, 4 ... Callide screen, 5 ... Light-shielding layer, 6 ... Diffusing agent, 7 ... Callide scope, 8 ... Incident surface, 9 ... Output surface, 10 ... Mirror.

Claims (6)

In a projection display device comprising a projection screen on which light is projected,
  A projection lens that receives light output from a light source and projects projection light toward the projection screen;
  An incident surface on which light projected from the projection lens is incident;
  A reflecting mirror that receives and reflects light incident on the incident surface;
  A projection screen provided with an exit surface that emits light reflected by the reflecting mirror;
  In the projection screen, the area of light incident on the incident surface is larger than the area of the exit surface, and the inner surface surrounding the space between the outer periphery of the entrance surface and the outer periphery of the exit surface is the reflector. A projection display device comprising a formed kaleidoscope, and a plurality of kaleidoscopes of different sizes arranged and distributed on a plane. 2. The projection display device according to claim 1, wherein an incident surface and an output surface of the kaleidoscope are substantially similar. 2. The projection display apparatus according to claim 1, wherein an incident surface and an output surface of the kaleidoscope are non-similar. 2. The projection display device according to claim 1, wherein a light shielding layer is formed in a screen region around the opening which is an emission surface of the kaleidoscope. 2. The projection display device according to claim 1 , wherein a light diffusing member is provided only on an opening portion of the exit surface of the kaleidoscope or on the entire screen on the exit surface side . The projection display apparatus according to claim 1, wherein the kaleidoscopes having different sizes are distributed on the screen, and a viewing angle characteristic of the screen is adjusted.

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