JP2022038300A - Image display device - Google Patents

Abstract

To provide an image display device which includes a screen made of a film with a fine uneven pattern including a lens having a substantially-vertical plane and in which the utilization efficiency of light is improved.SOLUTION: An image display device comprises: display light emission means (1); and a screen made of a film (2) with a fine uneven pattern. The film with a fine uneven pattern includes a plurality of lenses (10L) made of protrusions and recesses having a substantially-vertical plane (S1) and a curved plane (S2) on one surface. The film (2) with a fine uneven pattern is arranged in a flat state or in such a state that at least a portion is curved in the image display device. For any one lens, when a ratio of light incident on the substantially-vertical plane of the light emitted from the display light emission means and incident on one lens is defined as a loss ratio (%), the loss ratio is equal to or less than 5% in the lenses in the number equal to or greater than 50% with respect to the total number of the lenses.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image display device including a screen made of a film having a fine concavo-convex pattern.

A head-up display device (HUD) for a vehicle is a device that provides a virtual image in front of a windshield. Since the driver can obtain necessary information without looking away from the driving direction, he / she can drive safely. With the increase in definition of the display device, a microlens array in which a plurality of microlenses are arranged in a two-dimensional matrix is widely used as an imaging screen.

Patent Document 1 relates to a screen including a microlens array, and as an example of a lens shape, in addition to an example in which the lens surface is a curved surface as a whole (FIG. 3a), the lens surface is regarded as a substantially vertical surface in order to bend the optical axis. An example (Fig. 3b) in combination with a curved surface is shown.
Patent Document 2 discloses a scanning projector system including a two-dimensional scanning element that performs two-dimensional scanning of light and a screen including a microlens array (claim 1, paragraph 0028). In Patent Document 2, the screen is curved into a shape obtained by cutting out a part of a sphere centered on a two-dimensional scanning element (claim 1).

Japanese Unexamined Patent Publication No. 62-157023 Japanese Patent No. 6441197

In the lens shape described in Patent Document 1 in which the lens surface is a combination of a substantially vertical surface and a curved surface, when light is incident on the substantially vertical surface, it is not emitted in a desired direction, and the efficiency of light utilization is lowered.
Patent Document 2 describes the curvature of the screen, but does not specifically describe the lens shape, and does not disclose the design of the suitable curvature of the screen according to the lens shape.

In view of these problems, the present invention comprises a screen made of a film having a fine concavo-convex pattern including a lens having a substantially vertical plane, the amount of light incident on the substantially vertical plane of the lens is reduced, and the efficiency of light utilization is improved. It is an object of the present invention to provide the image display device.

The present invention provides the following image display devices [1] to [7].
[1] An image display including a display light emitting means that emits light for displaying an image and a screen made of a film having a fine uneven pattern on which an image formed by the display light emitted from the display light emitting means is projected. It ’s a device,
The film with a fine concavo-convex pattern comprises a convex portion or a concave portion having a substantially vertical surface having an angle in the range of 90 ° ± 10 ° with respect to the flat surface of the film having the fine concavo-convex pattern and a curved surface on one surface. It has multiple lenses and
The film with a fine concavo-convex pattern is arranged in a flat state in the image display device.
When the ratio of the light emitted from the display light emitting means to the arbitrary one lens and incident on the one lens and incident on the substantially vertical plane is defined as the loss rate (%).
An image display device having a loss rate of 5% or less in the lenses having a number of 50% or more with respect to the total number of the lenses.

[2] An image display including a display light emitting means that emits light for displaying an image and a screen made of a film having a fine uneven pattern on which an image formed by the display light emitted from the display light emitting means is projected. It ’s a device,
The film with a fine concavo-convex pattern comprises a convex portion or a concave portion having a substantially vertical surface having an angle in the range of 90 ° ± 10 ° with respect to the flat surface of the film having the fine concavo-convex pattern and a curved surface on one surface. It has multiple lenses and
The film with a fine concavo-convex pattern is arranged in the image display device in a state where at least a part thereof is curved.
When the ratio of the light emitted from the display light emitting means to the arbitrary one lens and incident on the one lens and incident on the substantially vertical plane is defined as the loss rate (%).
An image display device having a loss rate of 5% or less in the lenses having a number of 50% or more with respect to the total number of the lenses.

[3] An image display including a display light emitting means that emits light for displaying an image and a screen made of a film having a fine uneven pattern on which an image formed by the display light emitted from the display light emitting means is projected. It ’s a device,
The film with a fine concavo-convex pattern comprises a convex portion or a concave portion having a substantially vertical surface having an angle in the range of 90 ° ± 10 ° with respect to the flat surface of the film having the fine concavo-convex pattern and a curved surface on one surface. It has multiple lenses and
The film with a fine concavo-convex pattern is arranged in the image display device in a state where at least a part thereof is curved.
In a cross-sectional view that passes through the center of the light emitting surface of the display light emitting means and the center of the film having a fine concavo-convex pattern and vertically traverses the substantially vertical surface.
A straight line connecting the center of the light emitting surface of the display light emitting means and the center of the film having the fine concavo-convex pattern is used as a reference line, and any one of the film having the fine concavo-convex pattern is formed from the light emitting surface of the display light emitting means. The angle from the reference line in the emission direction of the light emitted toward the lens is defined as the emission angle (Z) [°].
When the ratio of the light emitted from the display light emitting means to the arbitrary one lens and incident on the one lens and incident on the substantially vertical plane is defined as the loss rate (%).
The loss rate of the lens to which the light emitted from the display light emitting means at an emission angle (Z) having an absolute value of 0 to 10 ° is incident is 4% or less.
The loss rate of the lens to which the light emitted from the display light emitting means at an emission angle (Z) having an absolute value of 10 to 20 ° is incident is 15% or less.
An image display device having a loss rate of 25% or less of the lens to which light emitted from the display light emitting means at an emission angle (Z) having an absolute value of 20 to 30 ° is incident.

[4] The image display device according to any one of [1] to [3], wherein the film with a fine concavo-convex pattern is made of resin.
[5] Any of [1] to [4], wherein the film with a fine concavo-convex pattern includes a base resin film and a concavo-convex resin layer formed on the base resin film and including the plurality of lenses. Image display device.
[6] The image display device according to any one of [1] to [5], wherein the film with a fine concavo-convex pattern includes a microlens array.
[7] The image display device according to any one of [1] to [6], which is a head-up display device.

According to the present invention, a screen made of a film having a fine concavo-convex pattern including a lens having a substantially vertical plane is provided, the amount of light incident on the substantially vertical plane of the lens is reduced, and the light utilization efficiency is improved. Equipment can be provided.

It is a schematic diagram which shows the whole structure of the head-up display device as the image display device of one Embodiment which concerns on this invention. It is a schematic plan view of the film with the fine concavo-convex pattern of one Embodiment which concerns on this invention. 2A is a cross-sectional view taken along the y-axis of the film with a fine concavo-convex pattern of FIG. 2A. 2A is a cross-sectional view taken along the x-axis of the film with a fine concavo-convex pattern of FIG. 2A. It is a schematic cross-sectional view which shows one design change example of the film with a fine concavo-convex pattern. It is a schematic cross-sectional view which shows the other design modification example of the film with a fine concavo-convex pattern. It is a schematic cross-sectional view which shows the other design modification example of the film with a fine concavo-convex pattern. When the film 2 with a fine concavo-convex pattern is arranged in the image display device 4 in a flat state (not curved), light is incident on the film 2 with a fine concavo-convex pattern from the display light emitting means 1. It is a schematic cross-sectional view which shows. A schematic cross section showing how light is incident on the film 2 with a fine concavo-convex pattern from the display light emitting means 1 when the film 2 with a fine concavo-convex pattern is arranged in the image display device 4 in a partially curved state. It is a figure. A schematic cross section showing how light is incident on the film 2 with a fine concavo-convex pattern from the display light emitting means 1 when the film 2 with a fine concavo-convex pattern is arranged in the image display device 4 in a curved state as a whole. It is a figure. FIG. 3 is a cross-sectional view in the y-axis direction showing an enlarged state in which light is incident on one microlens 10L when the angle V of the substantially vertical plane S1 is 90 °. FIG. 3 is a cross-sectional view in the y-axis direction showing an enlarged state in which light is incident on one microlens 10L when the angle V of the substantially vertical plane S1 is larger than 90 °. FIG. 3 is a cross-sectional view in the y-axis direction showing an enlarged state in which light is incident on one microlens 10L when the angle V of the substantially vertical plane S1 is smaller than 90 °. It is a schematic cross-sectional view which shows the example of the ray diagram after the light has passed through one microlens 10L. It is explanatory drawing of the microlens design in the section of [Example]. It is explanatory drawing of the microlens design in the section of [Example].

Hereinafter, embodiments according to the present invention will be described.
In the image display device of the present invention, a display light emitting means that emits light for displaying an image (also referred to as display light or video light) and an image formed by the display light emitted from the display light emitting means are projected. It is provided with a screen made of a film having a fine concavo-convex pattern.
The image display device of the present invention can be preferably applied to a head-up display device (HUD) or the like.

The overall configuration of the head-up display device as the image display device of the embodiment according to the present invention will be described. FIG. 1 is a schematic view showing an overall configuration of a head-up display device for a vehicle.
The head-up display device 4 includes a display light emitting means 1 that emits light for displaying an image (display light or video light), and a screen (also referred to as an intermediate screen) made of a film 2 with a fine concavo-convex pattern.
The display light emitting means 1 is not particularly limited, and light from a light source such as a DLP (Digital Light Processing), a light emitting diode (LED), and a laser light source is reflected by a micromirror device, a reflective liquid crystal device, or the like. Devices and the like can be mentioned.
In the head-up display device 4, the light (display light or image light) emitted from the display light emitting means 1 is imaged on a screen made of a film 2 having a fine concavo-convex pattern, and is magnified and reflected by the concave mirror 3. The magnified reflected light (display light or image light) 5 is reflected on the inner surface of the windshield 6 of the vehicle and is visually recognized by the driver 8 as a virtual image 7 visible in front of the outside of the windshield 6.

The film 2 with a fine concavo-convex pattern has a plurality of lenses having convex or concave portions having a substantially vertical surface and a curved surface on one surface. The lens is preferably a microlens. The film 2 with a fine concavo-convex pattern preferably includes a microlens array in which a plurality of microlenses are arranged in a two-dimensional matrix.
The film 2 with a fine concavo-convex pattern has a fine concavo-convex pattern formed on one surface by a plurality of lenses composed of convex portions or concave portions. The other front surface (also referred to as the back surface) of the film 2 with a fine concavo-convex pattern is a flat surface.
The film 2 with a fine concavo-convex pattern is preferably made of resin, and may be a single-layer film or a laminated film.
The screen made of the film 2 with a fine concavo-convex pattern is arranged in the image display device 4 in a flat state or at least a partially curved state. The angle of the substantially vertical plane of the lens with respect to the horizon can be arbitrarily designed.

As used herein, the term "substantially vertical surface" refers to a surface within a range of −10 to 10 ° (within a range of ± 10 °) from the direction perpendicular to the flat surface of the film having a fine concavo-convex pattern.
As used herein, the term "flat surface of a film" refers to a surface that is flat when the film is not curved.
As used herein, the term "curved surface of film" refers to a curved surface of a film in a non-curved state.
As used herein, the "flat state of the film" refers to the state in which the film is not curved.

2A to 2C are schematic views showing the configuration of a film with a fine concavo-convex pattern (hereinafter, may be simply abbreviated as “film”) according to the embodiment of the present invention.
FIG. 2A is a schematic plan view of the film, in which the lateral direction of the film (vertical direction in the drawing) is the x-axis direction, the longitudinal direction of the film (horizontal direction in the drawing) is the y-axis direction, and the thickness direction of the film (flat surface of the film). (Vertical direction with respect to) is the z-axis direction. 2B is a cross-sectional view of the film of FIG. 2A in the y-axis direction, and FIG. 2C is a cross-sectional view of the film of FIG. 2A in the x-axis direction.

In the present embodiment shown in FIGS. 2A to 2C, the film 2 with a fine concavo-convex pattern is a laminated film including a flat base material resin film 9 and an concavo-convex resin layer formed on the flat base material resin film 9.
As used herein, the term "flat substrate resin film" refers to a substrate resin film whose both sides are flat in a state where the film is not curved.
In the present embodiment, the uneven resin layer is a microlens array 10 in which a plurality of microlenses 10L are arranged in a two-dimensional matrix. In addition, in order to make it easy to see, each microlens 10L is shown larger than the actual one on the drawing. Hereinafter, the microlens is also simply referred to as a lens.

As shown in FIG. 2B, each microlens 10L has a flat surface of the film 2 with a fine concavo-convex pattern (specifically, a surface (back surface) of the film 2 with a fine concavo-convex pattern on the base resin film 9 side). It has a substantially vertical surface S1 and a curved surface S2. The curved surface S2 may be spherical or aspherical.
In the present specification, the angle of the substantially vertical plane S1 with respect to the flat plane (xy plane) of the film with the fine concavo-convex pattern is defined as “angle V”. The angle V is within the range of 90 ° ± 10 °.
As described above, the screen made of the film 2 with the fine concavo-convex pattern can be arranged in the image display device 4 in a flat state or at least a partially curved state, but the angle of the substantially vertical surface S1. V is an angle with respect to a flat surface (xy plane) of the film with a fine concavo-convex pattern when the film is in a flat state.

In the example shown in FIG. 2B, a substantially vertical plane S1 is formed at the left end of the illustration of all the microlenses 10L in the cross-sectional view in the y-axis direction. The film with a fine concavo-convex pattern of this design example is indicated by reference numeral 2a.
The position of the substantially vertical plane S1 can be appropriately designed according to the incident direction of the light. The position of the substantially vertical plane S1 may be changed by the microlens 10L.

An example of design change of the formation position of the substantially vertical plane in each microlens 10L will be described with reference to FIGS. 3A to 3C. These figures are schematic cross-sectional views corresponding to FIG. 2B.
Like the film 2b with a fine uneven pattern of the design modification example shown in FIG. 3A, a substantially vertical surface S1 may be formed at the right end of all the microlenses 10L in a cross-sectional view in the y-axis direction.
Like the film 2c with a fine concavo-convex pattern of the design modification example shown in FIG. 3B, a substantially vertical surface S1 is formed at the right end of the micro lens 10L on the left half of the drawing in a cross-sectional view in the y-axis direction, and the micro on the right half of the drawing is shown. A substantially vertical surface S1 may be formed at the left end of the lens 10L in the drawing. In this design modification example, the substantially vertical plane S1 of each microlens 10L faces the center in the y-axis direction of the film.
Like the film 2d with a fine concavo-convex pattern in the design modification example shown in FIG. 3C, a substantially vertical surface S1 is formed at the left end of the microlens 10L in the left half of the drawing in a cross-sectional view in the y-axis direction, and the micro in the right half of the figure is shown. A substantially vertical surface S1 may be formed at the right end of the lens 10L in the drawing. In this design modification example, the substantially vertical plane S1 of each microlens 10L faces the film edge closer to each microlens.
The film 2 with a fine concavo-convex pattern includes the films 2a to 2d with a fine concavo-convex pattern.

In the examples shown in FIGS. 2B and 3A to 3C, the case where the shape design of all the microlenses 10L is the same is shown, but the pitch, the radius of curvature of the curved surface S2, and the substantially vertical direction are shown by the microlens 10L. The design such as the angle of the surface S1 may be changed.

The film 2 with a fine concavo-convex pattern is preferably made of resin.
The material of the base resin film 9 is not particularly limited, and a thermoplastic resin is preferable because it is excellent in processability and molding stability. For example, polycarbonate (PC), polyethylene terephthalate (PET), cycloolefin polymer (COP). , Polyethylene (PE), polypropylene (PP), and combinations thereof are preferable. The refractive index of the base resin film 9 is not particularly limited.

The material of the microlens array 10 (concave and convex resin layer) is not particularly limited, and an active energy ray-curable material that is cured by irradiation with active energy rays such as ultraviolet rays (UV) and electron beams is preferable. Among them, UV curable resins are preferable, and UV curable resins such as urethane acrylates, acrylic acrylates, and epoxy acrylates are more preferable because they are easy to cure and have excellent long-term stability such as reliability.
An active energy ray-curable material is poured into a mold of a microlens array 10, a base resin film 9 is placed on the base resin film 9, and then the active energy ray-curable material is cured by irradiation with active energy rays to obtain a cured product from the mold. By removing the film 2 having a fine concavo-convex pattern and the base resin film 9, the film 2 having a fine concavo-convex pattern can be manufactured.
The refractive index of the microlens array 10 (concave and convex resin layer) is not particularly limited, and is preferably 1.2 to 1.8, more preferably 1.4 to 1.6. If the refractive index is too small, the optical axis is difficult to bend, and if it is too large, total reflection occurs, which is not preferable.

As described above, the screen made of the film 2 with the fine concavo-convex pattern can be arranged in the image display device 4 in a flat state or at least a partially curved state.
FIG. 4 shows that when the film 2 with a fine concavo-convex pattern is arranged in the image display device 4 in a flat state (not curved), light is emitted from the display light emitting means 1 to the film 2 with the fine concavo-convex pattern. It is a schematic cross-sectional view which shows the state which is incident. This figure is a schematic cross-sectional view corresponding to FIG. 2B. This figure is a cross-sectional view which passes through the center of the light emitting surface of the display light emitting means 1 and the center M of the film 2 having a fine concavo-convex pattern, and traverses a substantially vertical surface S1. The center M of the film 2 with a fine concavo-convex pattern is the center of the flat surface (back surface) of the film.

The straight line connecting the center of the light emitting surface of the display light emitting means 1 and the center of the film 2 with the fine unevenness pattern is set as the reference line BL, and the film 2 having the fine unevenness pattern is arbitrary from the center of the light emitting surface of the display light emitting means 1. The angle of the light (display light 12) emitted toward the one microlens 10L from the reference line BL in the emission direction is defined as the emission angle Z [°].
Here, the film 2c with a fine concavo-convex pattern is used as the film 2 with a fine concavo-convex pattern, but it can be similarly defined by using the film 2 with a fine concavo-convex pattern in any of the design examples.

Preferably, the straight line (reference line BL) connecting the center of the light emitting surface of the display light emitting means 1 and the center of the film 2 with the fine concavo-convex pattern substantially coincides with the normal line with respect to the flat surface of the film 2 having the fine concavo-convex pattern. As described above, the positional relationship between the display light emitting means 1 and the film 2 with a fine concavo-convex pattern is designed. Specifically, the line direction of the straight line (reference line BL) connecting the center of the light emitting surface of the display light emitting means 1 and the center of the film 2 with the fine unevenness pattern is the flat surface of the film 2 with the fine unevenness pattern. It is designed to be oriented in the range of 90 ° ± 10 °.

FIG. 5A shows how light (display light 12) is incident on the film 2 with a fine concavo-convex pattern from the display light emitting means 1 when the film 2 with a fine concavo-convex pattern is arranged in a partially curved state. It is a schematic cross-sectional view which shows. FIG. 5B shows how light (display light 12) is incident on the film 2 with a fine concavo-convex pattern from the display light emitting means 1 when the film 2 with a fine concavo-convex pattern is arranged in a curved state as a whole. It is a schematic cross-sectional view which shows. These figures are schematic cross-sectional views corresponding to FIG. 2B.

As shown in FIG. 5A, when the substantially vertical planes S1 of all the microlenses 10L are oriented in the same direction, half of the film 2 with a fine concavo-convex pattern can be curved toward the display light emitting means 1. In the illustrated example, only the right half of the illustrated film 2 with a fine concavo-convex pattern is curved while maintaining a flat state. For example, half of the film 2 with a fine concavo-convex pattern can be curved in a circular arc shape with a cross-sectional view centered on the center of the light emitting surface of the display light emitting means 1.

As shown in FIG. 5B, when the substantially vertical surface S1 of all the microlenses 10L faces the center M of the film 2 with the fine concavo-convex pattern, the entire film can be curved toward the display light emitting means 1. For example, the entire film 2 with a fine concavo-convex pattern can be curved in a circular arc shape in a cross-sectional view with the center of the light emitting surface of the display light emitting means 1 as the center.
In this example, for example, in a cross-sectional view, a film with a fine concavo-convex pattern is centered on a straight line (reference line BL) connecting the center of the light emitting surface of the display light emitting means 1 and the center of the film 2 with the fine concavo-convex pattern. 2 can be curved line-symmetrically.
The film 2 with a fine concavo-convex pattern can be curved three-dimensionally. For example, the film 2 with a fine concavo-convex pattern may be three-dimensionally curved point-symmetrically around a certain point on the reference line BL.

In the design example as shown in FIGS. 5A and 5B, the emission direction of the light from the display light emitting means 1 toward the arbitrary one microlens 10L and the substantially vertical plane S1 of the microlens 10L to which the light is incident are parallel to each other. Or it can be designed to be close to it. In such a design, since the amount of light incident on the substantially vertical plane S1 is reduced, the efficiency of light utilization can be improved, which is preferable.

6A to 6C are enlarged cross-sectional views in the y-axis direction showing how light (display light 12) is incident on one microlens 10L. These figures are schematic cross-sectional views corresponding to FIG. 3A.
FIG. 6A is a schematic cross-sectional view when the angle V of the substantially vertical plane S1 with respect to the xy plane is 90 °.
FIG. 6B is a schematic cross-sectional view when the angle V of the substantially vertical plane S1 with respect to the xy plane is larger than 90 °. In the illustrated example, the angle V is 90 ° + 10 °.
FIG. 6C is a schematic cross-sectional view when the angle V of the substantially vertical plane S1 with respect to the xy plane is smaller than 90 °. In the illustrated example, the angle V is 90 ° −10 °.

Generally, in a lens having a substantially vertical plane and a curved surface, when light is incident on the substantially vertical plane, it does not emit light in a desired direction, and the efficiency of light utilization is lowered.
The ratio of the light emitted from the display light emitting means 1 and incident on one lens (microlens 10L) (display light 12) and incident on the substantially vertical plane S1 is defined as the “loss rate”. The loss rate is expressed by the following formula.
General formula: [Loss rate] (%) = b / (a + b) × 100 Here, b is the arrival of light (display light 12) that reaches the bottom surface of the lens (microlens 10L) through the substantially vertical surface S1. The range is shown, and the distance between the position where the display light 12 incident on the microlens 10L through the upper end of the substantially vertical surface S1 reaches the bottom surface of the microlens 10L and the lower end of the substantially vertical surface S1 is shown.
a is the length obtained by subtracting b from the pitch of the microlens 10L.

Although FIGS. 6A to 6C show the case where the bottom surface of the microlens 10L is flat, the size of each microlens 10L is small even when the microlens array 10 is curved, so that the microlens is a microlens. The bottom surface of 10 L can be regarded as flat, and the loss rate can be obtained in the same manner as described above.

In one aspect, from the viewpoint of improving the efficiency of light utilization, it is preferable to design the lens so that the loss rate is 5% or less in the number of lenses of 50% or more with respect to the total number of lenses.
For example, as shown in Tables 1 to 3 in the section of [Example] described later, the ratio of light incident on the substantially vertical surface S1 is reduced to improve the efficiency of light utilization and satisfy the above-mentioned regulations. Various parameters of the lens (eg, pitch, radius of curvature of the curved surface, and amount of deviation of the apex Δ, etc.), bending angle of the film, or a combination thereof can be designed.

The size of various parameters of the microlens 10L is not particularly limited, the pitch is, for example, about 20 to 200 μm, the radius of curvature of the curved surface S2 is, for example, about 10 to 700 μm, and the height of the substantially vertical surface S1 is, for example, about 2 to 100 μm. ..

In the present invention, the loss rate is preferably 5% or less, more preferably 4% or less, and particularly preferably 3% or less in a lens having a number of 50% or more with respect to the total number of lenses. preferable.
From the viewpoint of improving the efficiency of light utilization, the ratio of the number of lenses having a loss rate of 5% or less is preferably large, and the ratio of the number of lenses having a loss rate of 5% or less is more preferably 65. % Or more, particularly preferably 80% or more.

As shown in FIG. 5B, when the film 2 with a fine concavo-convex pattern is curved and arranged,
As an alternative or addition to the above design in which the loss rate is 5% or less in the number of lenses of 50% or more with respect to the total number of lenses.
The loss rate of the microlens 10L to which the light emitted from the display light emitting means 1 at an emission angle (Z) having an absolute value of 0 to 10 ° is incident is 4% or less.
The loss rate of the microlens 10L to which the light emitted from the display light emitting means 1 at an emission angle (Z) having an absolute value of 10 to 20 ° is incident is 15% or less.
It may be designed so that the loss rate of the microlens 10L to which the light emitted from the display light emitting means 1 at an emission angle (Z) having an absolute value of 20 to 30 ° is incident is 25% or less.

FIG. 7 is a schematic cross-sectional view showing an example of a ray diagram after the display light 12 has passed through one microlens 10L. This figure is a schematic cross-sectional view corresponding to FIG. 6A, and is a schematic cross-sectional view when the angle V of the substantially vertical plane S1 with respect to the xy plane is 90 °. In this figure, the x-axis direction, the y-axis direction, and the z-axis direction are the same as in FIG. 6A, but the center of the microlens 10L in the y-axis direction is the origin O.
In the microlens 10L, the angle formed by the ray 13 emitted from the end on the opposite side of the substantially vertical plane S1 and the line parallel to the z-axis is the refraction angle A, and the end on the substantially vertical plane S1 side (substantial vertical plane S1). The angle formed by the light ray 14 incident from the upper end of the microlens 10L and the line parallel to the z-axis is defined as the refraction angle B. Let θ be the angle formed by the y-axis and the straight line connecting the intersection of the light rays 13 and the light rays 14 and the origin O. At these angles, the direction of the arrow in the figure is the positive direction.
FIG. 7 shows how the light incident on each position of the lens surface of the microlens 10L having the substantially vertical surface S1 is emitted from the microlens 10L with its optical axis bent.

As described above, according to the present invention, a screen made of a film having a fine concavo-convex pattern including a lens having a substantially vertical plane is provided, light incident on the substantially vertical plane of the lens is reduced, and light utilization efficiency is improved. An image display device can be provided.

Hereinafter, Examples and Comparative Examples according to the present invention will be described.
[Examples 1 to 9, Comparative Examples 1 and 2]
8A and 8B are explanatory views of the shape design of the microlens in the section of [Example].
First, in the yz plane shown in FIG. 8A, a circle having a center in a negative region on the z-axis and a radius larger than the distance between the origin and the center was drawn. The y-coordinates of the two intersections of this circle and the y-axis were set to p and −p (here, p> 0). The range of z ≧ 0 (region indicated by dots) of this circle was defined as the cross-sectional shape of the spherical microlens LS in the y-axis direction.

Based on the above spherical microlens LS, a microlens lens LV having a substantially vertical plane S1 as shown in FIG. 8B was designed.
In FIG. 8B, the center of the circle shown in FIG. 8A is shifted diagonally upward to the right in the drawing, and a substantially vertical line is drawn on the y-axis from a point on the circumference located at y> 0 and z> 0, and a region indicated by dots. Was defined as the y-axis direction cross-sectional shape of the microlens LV having a substantially vertical plane S1. This microlens lens LV has the same radius of curvature and pitch as the spherical microlens lens LS. In FIG. 8B, Δ indicates the amount of deviation (also referred to as the amount of deviation of the apex) between the apex of the lens shown in FIG. 8A and the apex of the lens shown in FIG. 8B in the y-axis direction.
In each example, the pitch of the microlens LV, the radius of curvature of the curved surface S2, the amount of deviation of the vertices Δ, and the angle V of the substantially vertical surface S1 were designed.

The angle V of the substantially vertical plane S1 with respect to the xy plane is the angle of the substantially vertical plane S1 with respect to the bottom surface of the lens, and is obtained with the angle of the bottom surface of the lens being 0 ° and the clockwise direction (direction of the arrow in the figure) as the positive direction. The angle. In each of Examples 1 to 9 and Comparative Examples 1 and 2, the angle V of the substantially vertical plane S1 is 90 ° (see FIG. 6A), 90 ° + 10 ° (see FIG. 6B), 90 ° -10 °. One of the conditions (see FIG. 6B) was used.

In each of Examples 1 to 4 and Comparative Example 1, a plurality of microlens LVs having a substantially vertical plane S1 as shown in FIG. 8B have a substantially vertical plane S1 facing the center as shown in FIG. 3B. A film with a fine concavo-convex pattern was designed, which is arranged in the axial direction and has a plurality of microlens arrays in which the rows are further arranged in the x-axis direction. In these examples, as shown in FIG. 4, the film with a fine concavo-convex pattern is designed to be arranged in a flat state in the image display device (no bending).

In each of Examples 5 to 8 and Comparative Example 2, a plurality of microlens LVs having a substantially vertical plane S1 as shown in FIG. 8B have a substantially vertical plane S1 facing the center as shown in FIG. 3B. A film with a fine concavo-convex pattern was designed, which is arranged in the axial direction and has a plurality of microlens arrays in which the rows are further arranged in the x-axis direction. In these examples, as shown in FIG. 5B, the film with a fine concavo-convex pattern is designed to be arranged in the image display device in a state of being curved in a circular arc shape as a whole (overall curved).

In Example 9, a plurality of microlens LVs having a substantially vertical plane S1 as shown in FIG. 8B are arranged in the y-axis direction with the substantially vertical plane S1 facing the center as shown in FIG. 3B, and this row is arranged. Furthermore, a film with a fine concavo-convex pattern having a plurality of microlens arrays arranged in the x-axis direction was designed. In these examples, as shown in FIG. 5A, the film with a fine concavo-convex pattern is designed to be arranged in the image display device in a state where only half of the film is curved in a cross-sectional view arc shape (half-curved).

As a representative, the design conditions in Example 1 are shown below.
Refractive index: 1.52,
Angle V: 90 ° of the substantially vertical plane S1 of the microlens 10L with respect to the xy plane,
Microlens 10L pitch: 20μm,
Radius of curvature of curved surface S2 of microlens 10L: 60 μm,
Amount of shift of the apex of the microlens 10L Δ: 10 μm,
Height of the apex of the microlens 10L: 3.4 μm,
Height of substantially vertical surface S1 of microlens 10L: 3.4 μm.
Emission angle Z: 30 ° from the display light emitting means of the light emitted from the display light emitting means and incident on the film edge of the film having a fine concavo-convex pattern.
Film bending angle: 0 ° (no bending).
The bending angle of the film is the angle formed by the line connecting the center M of the film and the edge of the film and the y-axis, and the bending angle of the film is 0 ° under the condition of no bending.

In Example 2, the pitch of the microlens was 200 μm, the radius of curvature was 620 μm, the apex shift amount Δ was 60 μm, and the microlens 10L was designed as shown in Table 1.
In Example 3, the angle V of the substantially vertical plane S1 was set to 90 ° + 10 ° as shown in FIG. 6B, and the microlens 10L was designed as shown in Table 1.
In Example 4, the angle V of the substantially vertical plane S1 was set to 90 ° −10 ° as shown in FIG. 6C, and the microlens 10L was designed as shown in Table 1.

In Example 5, the pitch of the microlens is 50 μm, the radius of curvature is 46 μm, the apex shift amount Δ is 10 μm, and as shown in FIG. 5B, the film with a fine concavo-convex pattern is entirely curved to change the bending angle of the film. It was set to 5 °.
In Example 6, the pitch of the microlens was 200 μm, the radius of curvature was 184 μm, the apex shift amount Δ was 60 μm, the bending angle of the film was 9 °, and the microlens 10L was designed as shown in Table 1.
In Example 7, the pitch of the microlens is 50 μm, the radius of curvature is 46 μm, the apex shift amount Δ is 5 μm, and the angle V of the substantially vertical plane S1 is 90 ° −10 ° as shown in FIG. 6C, as shown in Table 1. The microlens 10L was designed as shown.

In Example 8, a film with a fine concavo-convex pattern was designed in the same manner as in Example 5. In this example, the entire cross section of the film 2 with a fine concavo-convex pattern is centered on the center of the light emitting surface of the display light emitting means 1 and the radius is from the center of the light emitting surface of the display light emitting means 1 to the center M of the film. It was curved in a visual arc shape (the bending angle of the film is arbitrary).
In Example 9, as shown in FIG. 5A, the film was designed in the same manner as in Example 5 except that half of the film with a fine concavo-convex pattern was curved. In this example, half of the film 2 with a fine concavo-convex pattern is cross-sectionald with the center of the light emitting surface of the display light emitting means 1 as the center and the radius from the center of the light emitting surface of the display light emitting means 1 to the center M of the film. It was curved in a visual arc shape (the bending angle of the film is arbitrary).

In Comparative Example 1, the pitch of the microlens was 100 μm, the radius of curvature was 124 μm, the apex shift amount Δ was 50 μm, and the microlens 10L was designed as shown in Table 3.
Comparative Example 2 was designed in the same manner as in Example 6 except that the bending angle of the film was 4 °.

For the lens, the pitch and radius of curvature of the microlens are determined, the diffusion angle of the lens is determined from these, and then the bending angle of the optical axis is determined by the amount of shift of the apex Δ, and the shape is designed. can. The height of the apex of the lens and the height of the substantially vertical plane are uniquely determined from these parameters. Diffusion angle ± 5 ° in Examples 1 to 4, bending angle of optical axis 5 °, diffusion angle ± 15 ° in Comparative Example 1, bending angle of optical axis 15 °, diffusion angle in Examples 5 to 9 and Comparative Example 2. It was designed with a bending angle of ± 25 ° and an optical axis of 25 °.

As described with reference to FIGS. 6A to 6C for each example, the loss rate (display emitted from the display light emitting means 1 at an emission angle Z and incident on one microlens 10L) is based on the following equation. Of the light, the ratio of the light incident on the substantially vertical plane S1) was calculated.
General formula: [Loss rate] (%) = b / (a + b) × 100
The emission angle Z was set to four conditions of 10 °, 15 °, 20 °, and 30 °.

The calculation results of the design conditions and the loss rate in Examples 1 to 9 and Comparative Examples 1 and 2 are shown in Tables 1 to 3. In each example, the conditions not shown in the table are common conditions.

[Summary of results]
In Examples 1 to 8 and Comparative Examples 1 and 2, the films having a fine concavo-convex pattern are arranged line-symmetrically in a cross-sectional view, and the light emitted from the display light emitting means and incident on the film edge of the film having the fine concavo-convex pattern is displayed. Since the emission angle Z from the light emitting means is set to 30 °, if the loss rate is 5% or less under the condition that the emission angle Z is 15 ° or less, the loss is 50% or more of the total number of lenses. It can be determined that the rate is 5% or less.

In Example 9, since the film with the fine concavo-convex pattern was curved only half, the loss rate under the conditions of the emission angles Z of 10 °, 15 °, 20 °, and 30 ° for any half was 5% or less. For example, it can be determined that the loss rate is 5% or less in the number of lenses having a number of 50% or more with respect to the total number of lenses.

In Examples 1 to 8, by appropriately designing various parameters of the lens, the bending angle of the film, or a combination thereof, the light incident on the substantially vertical surface S1 is reduced, the utilization efficiency of the light is improved, and the lens is used. The loss rate could be 5% or less in the number of lenses of 50% or more with respect to the total number of lenses.

In Examples 1 to 8, the loss rate of the microlens 10L to which the light emitted from the display light emitting means 1 at an emission angle (Z) having an absolute value of 0 to 10 ° is incident is set to 4% or less, and the display light emitting means. The loss rate of the microlens 10L to which the light emitted from 1 at an emission angle (Z) having an absolute value of 10 to 20 ° is set to 15% or less, and the emission from the display light emitting means 1 has an absolute value of 20 to 30 °. The loss rate of the microlens 10L to which the light emitted at the angle (Z) is incident can be set to 25% or less.

Above all, in Example 8 in which the entire film with a fine concavo-convex pattern is curved in a circular arc shape in a cross-sectional view around the center of the light emitting surface of the display light emitting means, the loss rate is set to 0% in all the lenses of the film. It was possible to improve the efficiency of light utilization to the maximum.

In Example 9 in which the film with the fine concavo-convex pattern was curved only half, the loss rate could be set to 0% as a whole in the curved side half.

In the designs of Comparative Examples 1 and 2, the loss rate was large as a whole.

In Examples 1 to 4, since the radius of curvature of the lens curved surface was designed to be relatively large with respect to the lens pitch and the height of the substantially vertical plane was designed to be relatively low, the loss rate could be reduced as a whole. In contrast to these examples, in Comparative Example 1, the radius of curvature of the lens curved surface was made relatively small with respect to the lens pitch, and the height of the substantially vertical plane was made relatively high, so that the loss rate was increased as a whole.
In Examples 5 to 8, the radius of curvature of the lens curved surface was made relatively small with respect to the lens pitch, and the height of the substantially vertical plane was made relatively high. However, the film was curved to emit display light for each lens. By designing so that the emission direction of the emitted light from the means and the substantially vertical plane of the lens are parallel to or close to each other, the loss rate can be reduced as a whole.
In Comparative Example 2, the loss rate could not be sufficiently reduced because the bending angle was insufficient.

The present invention is not limited to the above embodiments and examples, and the design can be appropriately changed as long as the gist of the present invention is not deviated.

1 Display light emitting means 2, 2a to 2d Film with fine uneven pattern 4 Head-up display device (image display device)
9 Base resin film 10 Microlens array (concave and convex resin layer)
10L Microlens 12 Display light S1 Approximately vertical surface S2 Curved surface V Approximately vertical surface angle Z Emission angle BL Reference line M Center of film with fine concavo-convex pattern

Claims (7)

An image display device including a display light emitting means that emits light for displaying an image and a screen made of a film having a fine uneven pattern on which an image formed by the display light emitted from the display light emitting means is projected. hand,
The film with a fine concavo-convex pattern comprises a convex portion or a concave portion having a substantially vertical surface having an angle in the range of 90 ° ± 10 ° with respect to the flat surface of the film having the fine concavo-convex pattern and a curved surface on one surface. It has multiple lenses and
The film with a fine concavo-convex pattern is arranged in a flat state in the image display device.
When the ratio of the light emitted from the display light emitting means to the arbitrary one lens and incident on the one lens and incident on the substantially vertical plane is defined as the loss rate (%).
An image display device having a loss rate of 5% or less in the lenses having a number of 50% or more with respect to the total number of the lenses. An image display device including a display light emitting means that emits light for displaying an image and a screen made of a film having a fine uneven pattern on which an image formed by the display light emitted from the display light emitting means is projected. hand,
The film with a fine concavo-convex pattern comprises a convex portion or a concave portion having a substantially vertical surface having an angle in the range of 90 ° ± 10 ° with respect to the flat surface of the film having the fine concavo-convex pattern and a curved surface on one surface. It has multiple lenses and
The film with a fine concavo-convex pattern is arranged in the image display device in a state where at least a part thereof is curved.
When the ratio of the light emitted from the display light emitting means to the arbitrary one lens and incident on the one lens and incident on the substantially vertical plane is defined as the loss rate (%).
An image display device having a loss rate of 5% or less in the lenses having a number of 50% or more with respect to the total number of the lenses. An image display device including a display light emitting means that emits light for displaying an image and a screen made of a film having a fine uneven pattern on which an image formed by the display light emitted from the display light emitting means is projected. hand,
The film with a fine concavo-convex pattern comprises a convex portion or a concave portion having a substantially vertical surface having an angle in the range of 90 ° ± 10 ° with respect to the flat surface of the film having the fine concavo-convex pattern and a curved surface on one surface. It has multiple lenses and
The film with a fine concavo-convex pattern is arranged in the image display device in a state where at least a part thereof is curved.
In a cross-sectional view that passes through the center of the light emitting surface of the display light emitting means and the center of the film having a fine concavo-convex pattern and vertically traverses the substantially vertical surface.
A straight line connecting the center of the light emitting surface of the display light emitting means and the center of the film having the fine concavo-convex pattern is used as a reference line, and any one of the film having the fine concavo-convex pattern is formed from the light emitting surface of the display light emitting means. The angle from the reference line in the emission direction of the light emitted toward the lens is defined as the emission angle (Z) [°].
When the ratio of the light emitted from the display light emitting means to the arbitrary one lens and incident on the one lens and incident on the substantially vertical plane is defined as the loss rate (%).
The loss rate of the lens to which the light emitted from the display light emitting means at an emission angle (Z) having an absolute value of 0 to 10 ° is incident is 4% or less.
The loss rate of the lens to which the light emitted from the display light emitting means at an emission angle (Z) having an absolute value of 10 to 20 ° is incident is 15% or less.
An image display device having a loss rate of 25% or less of the lens to which light emitted from the display light emitting means at an emission angle (Z) having an absolute value of 20 to 30 ° is incident. The image display device according to any one of claims 1 to 3, wherein the film with a fine uneven pattern is made of resin. The film according to any one of claims 1 to 4, wherein the film with a fine concavo-convex pattern includes a base resin film and a concavo-convex resin layer formed on the base resin film and including the plurality of lenses. Image display device. The image display device according to any one of claims 1 to 5, wherein the film with a fine concavo-convex pattern includes a microlens array. The image display device according to any one of claims 1 to 6, which is a head-up display device.

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