JP2024041349A - image display device - Google Patents

Abstract

To provide an image display device which is small and can realize high light usage efficiency.SOLUTION: An image display device includes: an image display element; light control means having an angle separation surface which reflects a light flux from a light source to the image display element and transmits a light flux from the image display element; and a light guide plate for guiding a light flux from the light control means. An angle at which a main light beam of a light flux from the light source enters the angle separation surface and an angle at which a main light beam of a light flux from the image display element enters the angle separation surface are adequately set.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image display device that allows an observer to view an image.

2. Description of the Related Art Conventionally, image display devices including a light guide plate are known. FIG. 10 is a conceptual diagram of a light beam propagating inside a light guide plate in a conventional image display device. The light beam from the image generating element enters the first deflection means 1, is deflected, and then propagated inside the light guide plate 3 by total reflection. A part of the light beam incident on the second deflection means 2 is deflected and directed toward the observer's pupil SP, and the other part is reflected and propagated inside the light guide plate 3 by total reflection, and 2. With this configuration, a plurality of light beams are emitted from the second deflection means 2, and the area in which the observer can observe the light beams is expanded. Patent Document 1 discloses a configuration in which a PBS (polarizing beam splitter) is disposed between MEMS (Micro Electro Mechanical Systems) and a light guide plate in order to downsize an image display device.

US Patent Application Publication No. 2021/0072542

However, in the configuration of Patent Document 1, since it is necessary to guide the polarized light to the PBS, it is necessary to arrange an optical element such as a polarizing plate, and the light utilization efficiency decreases. Furthermore, it is necessary to arrange a phase plate between the MEMS and the PBS, which increases the distance between the light guide plate and the MEMS. Furthermore, since the polarized light transmitted through the PBS is P-polarized light, it is necessary to place a phase plate on the exit side of the PBS in order to match the polarization direction with high diffraction efficiency of the diffraction grating, which may increase the size of the image display device. There is sex.

An object of the present invention is to provide an image display device that is compact and can realize high light utilization efficiency.

An image display device according to one aspect of the present invention includes an image display element, a light control means including an angular separation surface that reflects a light flux from a light source to the image display element and transmits a light flux from the image display element, and a light guide plate that guides the light flux from the means, the incident angle of the principal ray of the light flux from the light source on the angle separation plane is θ1 [°], and the incidence angle of the principal ray of the light flux from the image display element on the angle separation plane. When the angle is θ2 [°],
θ1≧θ2+10
It is characterized by satisfying the following conditional expression.

According to the present invention, it is possible to provide an image display device that is small and can realize high light utilization efficiency.

1 is a configuration diagram of an image display device of Example 1. FIG. 3 is an explanatory diagram of an optical path in the image display device of Example 1. FIG. FIG. 3 is a configuration diagram of a light source. FIG. 3 is a diagram showing the characteristics of an angle separation surface included in the light control means. FIG. 2 is a configuration diagram of an image display device according to a second embodiment. FIG. 3 is a configuration diagram of an image display device according to a third embodiment. FIG. 3 is a configuration diagram of an image display device according to a fourth embodiment. FIG. 3 is a configuration diagram of an image display device according to a fifth embodiment. FIG. 7 is a configuration diagram of an image display device according to a sixth embodiment. FIG. 3 is a conceptual diagram of a light beam propagating inside a conventional light guide plate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same reference numerals are given to the same members, and duplicate explanations will be omitted.

FIG. 1 is a configuration diagram of an image display device 100 of this embodiment. FIG. 2 is an explanatory diagram of the optical path in the image display device 100. The image display device 100 includes a light guide plate 10, a light source 11, MEMS (Micro Electro Mechanical Systems) 12, a light control means 13, an incident deflection means 14, and an exit deflection means 15. The MEMS 12 is a raster scan two-dimensional type that includes a swingable mirror and has a mirror deflection angle of 5 degrees (optical deflection angle of 10 degrees) around the x- and y-axes. Note that in this embodiment, the MEMS 12 is used as an example of the image display element, but other elements may be used. The entrance deflection means 14 and the exit deflection means 15 are coupled to the light guide plate 10 on the same plane.

The light beam emitted from the light source 11 enters the light control means 13. The light reflected by the light control means 13 enters the MEMS 12. The light beam reflected by the MEMS 12 passes through the light control means 13 and enters the incident deflection means 14. The light beam incident on the incident deflection means 14 is deflected by the incident deflection means 14 and propagated inside the light guide plate 10 by total reflection. The light beam incident on the light beam splitting/deflecting means 10a provided on the light guide plate 10 is divided and deflected in the x-axis direction and guided to the exit deflecting means 15. The light beam incident on the exit deflection means 15 is divided and deflected in the y-axis direction, and exits from the exit surface to the pupil SP. Incidentally, although the entrance deflection means 14, the beam splitting/deflecting means 10a, and the exit deflecting means 15 are a diffraction grating in this embodiment, they may be a hologram or a splitting mirror.

FIG. 3(a) is a configuration diagram of the light source 11. FIG. 3(b) is a diagram showing a distribution image of the light flux emitted from the light source 11. The light source 11 includes a light emitting section 16 and a collimator lens 17. The diffused light beam from the light emitting surface of the light emitting unit 16 is collimated by the collimator lens 17, and the light source 11 emits a collimated light beam having an elliptical distribution with the minor axis parallel to the z-axis direction, as shown in FIG. 3(b). In this embodiment, the light beam emitted from the light source 11 is a collimated light beam with a wavelength of 532 nm from a semiconductor laser, but it may be a collimated light beam that is a combination of light beams from red, green, and blue semiconductor lasers. Furthermore, a photonic crystal laser or a light emitting diode may be used instead of a semiconductor laser.

The light control means 13 includes a first angle separation surface 13a and a second angle separation surface 13b, and has a characteristic of transmitting or reflecting the light beam depending on the incident angle of the light beam incident on the angle separation surface. have In this embodiment, a dielectric multilayer film is deposited on the angle separation surface.

In this embodiment, the incident angle of the principal ray of the light beam emitted from the light source 11 and incident on each angle separation surface is 45 degrees, and the principal ray of the light beam reflected by MEMS 12 and incident on each angle separation surface (deflection angle of MEMS 12 The angle of incidence of the principal ray (when is 0°) is 0°.

FIG. 4 is a diagram showing the characteristics of the angle separation surface included in the light control means 13. FIG. 4(a) shows the relationship between wavelength and transmittance for each incident angle of the first angle separation surface 13a. FIG. 4(b) shows the relationship between wavelength and reflectance for each incident angle of the second angle separation surface 13b.

In this embodiment, the first angular separation surface 13a transmits 50% of the luminous flux incident on the light control means 13, and reflects 50% of the luminous flux. The second angle separation surface 13b reflects all the light beams that have passed through the first angle separation surface 13a. The light beam reflected by either the first angle separation surface 13a or the second angle separation surface 13b is guided to the MEMS 12. Therefore, the light beam can be guided to the MEMS 12 while the diameter of the light beam in the x-axis direction is approximately doubled. When guiding a light beam of the same size (for example, a light beam diameter in the x-axis direction is 1.0 mm) to the MEMS 12, the diameter of the light beam incident on the light control means 13 is reduced to approximately half (for example, a light beam diameter in the z-axis direction is 0.5 mm). can do. Therefore, the size of the light control means 13 in the z-axis direction can be approximately halved. In this embodiment, since the z-axis direction is parallel to the short axis of the elliptical distribution of the collimated light beam emitted from the light source 11, the distance between the MEMS 12 and the light guide plate 10 can be narrowed. Since the spread of the light beam incident on the incident deflection means 14 can be suppressed, high efficiency can be achieved with a compact configuration. When the light beam spreads, it is necessary to increase the size of the incident deflection means 14. When the incident deflection means 14 is made large, the light beam incident on the incident deflection means 14 is totally reflected on the opposing surface, then enters the incident deflection means 14 again, and is emitted from the incident deflection means 14 as unnecessary light, which improves the light utilization efficiency. decreases.

FIG. 5 is a configuration diagram of the image display device 200 of this embodiment. The image display device 200 includes a light source 21, a MEMS 22, a light control means 23, and a light guide plate 24. The MEMS 22 is a raster scan two-dimensional type that includes a mirror and has a mirror deflection angle of 5 degrees (optical deflection angle of 10 degrees) around the x-axis and the y-axis. The light control means 23 includes a first angle separation surface 23a and a second angle separation surface 23b, and has a characteristic of transmitting or reflecting the light beam depending on the incident angle of the light beam incident on the angle separation surface. have The light guide plate 24 is formed with an incident portion 24i into which the light beam from the light control means 23 is incident. The incident part 24i is formed on a surface (third surface) connected to two surfaces (first surface and second surface) that totally reflect the light beam from the light control means 23. The third surface is perpendicular to the first and second surfaces. Here, orthogonal includes not only strictly orthogonal cases but also substantially orthogonal cases. Although the incident part 24i is bonded to the light control means 23 in this embodiment, it may be separated from the light control means 23 and an antireflection film may be deposited thereon. Note that in this embodiment, the MEMS 22 is used as an example of the image display element, but other elements may be used.

The light beam emitted from the light source 21 enters the light control means 23. The light beam reflected by the light control means 23 enters the MEMS 22 . The light reflected by the MEMS 22 passes through the light control means 23 and enters the light guide plate 24 from the incident section 24i. The light beam incident on the light guide plate 24 is propagated through the interior of the light guide plate 24 by total reflection, is deflected by a light splitting/deflecting means (not shown), is emitted, and is guided to a pupil (not shown).

In this embodiment, there is no need to provide the incident deflection means described in the first embodiment, and it is possible to further improve the light utilization efficiency.

FIG. 6 is a configuration diagram of the image display device 300 of this embodiment. The image display device 300 includes a light source 31, a MEMS 32, a light control means 33, and a light guide plate 34. The MEMS 32 is a raster scan two-dimensional type that includes a mirror and has a mirror deflection angle of 5 degrees (optical deflection angle of 10 degrees) around the x-axis and the y-axis. Note that in this embodiment, the MEMS 32 is used as an example of the image display element, but other elements may be used.

The light beam emitted from the light source 31 enters the light control means 33. The light beam reflected by the light control means 33 enters the MEMS 32. The light reflected by the MEMS 32 passes through the light control means 33 and enters the light guide plate 34. The light beam incident on the light guide plate 34 is deflected and reflected by the slope 34a, propagated through the interior of the light guide plate 24 by total reflection, deflected by a light splitting/deflecting means (not shown) and emitted, and guided to a pupil (not shown).

FIG. 7 is a configuration diagram of the image display device 400 of this embodiment. The image display device 400 includes a light guide plate (not shown), a light source 41, a MEMS 42, a light control means 43, an incident deflection means (not shown), and an exit deflection means (not shown). The MEMS 42 is a raster scan two-dimensional type that includes a mirror and has a mirror deflection angle of 5 degrees (optical deflection angle of 10 degrees) around the x-axis and the y-axis. Note that in this embodiment, the MEMS 42 is used as an example of the image display element, but other elements may be used. The entrance deflection means and the exit deflection means are coupled to the light guide plate in the same plane.

The light beam emitted from the light source 41 enters the light control means 43. The light reflected by the light control means 43 enters the MEMS 42. The light beam reflected by the MEMS 42 passes through the light control means 93 and enters the incident deflection means.

The light control means 43 includes a first angle separation surface 43a, a second angle separation surface 43b, a third angle separation surface 43c, and a fourth angle separation surface 43d, and controls the incidence of the light beam incident on the angle separation surface. It has the property of transmitting or reflecting light depending on the angle.

The first angular separation surface 43a transmits 75% of the luminous flux incident on the light control means 43 and reflects 25% of the luminous flux. The second angle separation surface 43b transmits 67% of the light beam that has passed through the first angle separation surface 43a, and reflects 33% of the light beam. The third angle separation surface 43c transmits 50% of the light beam that has passed through the second angle separation surface 43b, and reflects 50% of the light beam. The fourth angle separation surface 43d reflects all the light beams that have passed through the third angle separation surface 43c.

By giving the above-mentioned characteristics to the angular separation surface provided in the light control means 43, the intensities of the light beams L1 to L4 transmitted through each of the first to fourth angular separation surfaces 43a to 43d guided to the incident deflection means can be made almost the same. Can be set to .

Since the diameter of the light beam incident on the light control means 43 can be reduced to about 1/4, the distance between the MEMS 42 and the light guide plate can be made narrower than in the first embodiment.

Although the light control means 43 includes four angular separation surfaces in this embodiment, the effects of the present invention can be obtained if it is provided with a plurality of angular separation surfaces.

The following describes the configuration of the image display device 400 of this embodiment that is preferably satisfied.

The light control means 43 is equipped with n angle separation surfaces (n is an integer of 2 or more), and the reflectance of the angle separation surface provided at the m-th (m is a positive integer) counting from the light source 41 side is R. (m), it is preferable that at least one of the following conditional expressions under the angle separation plane be satisfied.

R(m+1)/R(m)>1.0
If all the angular separation surfaces do not satisfy the above conditional expression, the intensity of the light beam emitted from the MEMS 42 on the side where it enters the light control means 43 becomes strong, uneven brightness occurs, and the quality of the input image is impaired.

In addition, it is more preferable that at least one of the continuous angle separation surfaces satisfies the following conditional expression.

R(m+1)/R(m)≧(n+1)/n
When the light control means 43 includes n angle separation surfaces (n is an integer of 2 or more), it is preferable that at least two of the plurality of angle separation surfaces satisfy the following conditional expression.

T(m)≧0.8
Here, T(m) is the incident angle at an angle θ2 on the m-th angular separation surface from the MEMS 42, which is the m-th angular separation surface (m is a positive integer) counting from the light source 41 side. This is the transmittance for the luminous flux. θ2 is the incident angle of the principal ray of the light beam reflected by the MEMS 42 and incident on the angle separation surface (the principal ray when the deflection angle of the MEMS 42 is 0°).

Note that it is more preferable that at least two of the plurality of angle separation surfaces satisfy the following conditional expression.

T(m)≧0.9

FIG. 8 is a configuration diagram of an image display device 500 of this embodiment. The image display device 500 includes a light source 51, a MEMS 52, a triangular prism 53, and a light guide plate 54. The MEMS 52 is a raster scan two-dimensional type that includes a mirror and has a mirror deflection angle of 5 degrees (optical deflection angle of 10 degrees) around the x-axis and the y-axis. Note that in this embodiment, the MEMS 52 is used as an example of the image display element, but other elements may be used.

The light beam emitted from the light source 51 enters the triangular prism 53. The light beam reflected by the slope 53a of the triangular prism 53 enters the MEMS 52. The light reflected by the MEMS 52 passes through the slope 53 a of the triangular prism 53 and enters the light guide plate 54 from the slope 54 a of the light guide plate 54 . That is, in this embodiment, the slope 53a functions as an angle separation surface. The slope 53a of the triangular prism 53 and the slope 54a of the light guide plate 54 are separated by a predetermined air interval and are substantially parallel to each other. If the predetermined air gap becomes too large, astigmatism will occur in the light beam reflected from the MEMS 52, so it is preferable that the predetermined air gap is 100 μm or less. More preferably, it is 30 μm or less. The light flux incident on the light guide plate 54 is propagated through the interior of the light guide plate 54 by total reflection, is deflected by a light splitting/deflecting means (not shown), is emitted, and is guided to a pupil (not shown).

FIG. 9 is a configuration diagram of an image display device 600 of this embodiment. The image display device 600 includes a light source 61, a MEMS 62, a first triangular prism 63, a second triangular prism 64, a light guide plate 65, an incident deflection means 66, and an exit deflection means (not shown). The MEMS 62 is a raster scan two-dimensional type that includes a mirror and has a mirror deflection angle of 5 degrees (optical deflection angle of 10 degrees) around the x- and y-axes. The first triangular prism 63 and the second triangular prism 64 constitute a total internal reflection prism. Note that in this embodiment, the MEMS 62 is used as an example of the image display element, but other elements may be used. The entrance deflection means 66 and the exit deflection means are coupled to the light guide plate 65 on the same plane.

The light beam emitted from the light source 61 enters the first triangular prism 63. The light beam reflected by the slope 63a of the first triangular prism 63 enters the MEMS 62. The light reflected by the MEMS 62 passes through the slope 63a of the first triangular prism 63 and the second triangular prism 64, and enters the incident deflection means 66. The slope 63a of the first triangular prism 63 and the slope 64a of the second triangular prism 64 are separated by a predetermined air gap and are substantially parallel. Preferably, the predetermined air spacing is 100 μm or less. More preferably, it is 30 μm or less. The light beam incident on the light guide plate 65 is propagated through the interior of the light guide plate 65 by total reflection, is deflected by a light splitting/deflecting means (not shown), is emitted, and is guided to a pupil (not shown).

The characteristic configuration of the image display device of each embodiment will be described below.

The image display device of each example satisfies the following conditional expression (1).

θ1≧θ2+10 (1)
Here, θ1 is the angle at which the chief ray of the light beam from the light source is incident on the angle separation surface. θ2 is the angle at which the chief ray of the light beam from the image display element is incident on the angle separation surface. In each example, a MEMS is used as an image display element. In this case, θ2 is the principal ray of the light beam reflected by the MEMS and incident on each angle separation surface (when the deflection angle of the MEMS is 0°). is the angle of incidence of the chief ray). If conditional expression (1) is not satisfied, it becomes difficult to design a dielectric multilayer film that separates transmission and reflection with a predetermined performance, resulting in a decrease in light utilization efficiency.

Note that it is preferable that the numerical range of conditional expression (1) be the numerical range of conditional expression (1a) below.

θ1≧θ2+30 (1a)
Furthermore, it is more preferable that the numerical range of conditional expression (1) be the numerical range of conditional expression (1b) below.

θ1≧θ2+45 (1a)
Conditions that are preferably satisfied by the image display device of this example will be described below.

When the light control means includes a first angular separation surface and a second angular separation surface, which are provided in order from the side closer to the surface on which the light beam from the light source of the light control means is incident, the image display device of each embodiment preferably satisfies conditional expression (2) below.

1.00<R2/R1≦5.00 (2)
Here, R1 is the reflectance of the first angle separation surface at the dominant wavelength of the light beam from the light source. R2 is the reflectance at the main wavelength of the light flux from the light source on the second angle separation surface. Conditional expression (2) is the reflectance at the main wavelength of the light flux from the light source on the first angle separation surface, and defines the reflectance at the dominant wavelength of the light beam from the light source on the angle separation surface. When the lower limit of conditional expression (2) is exceeded and the reflectance at the main wavelength of the light beam from the light source on the second angle separation surface becomes low, the intensity of the reflected light on the first angle separation surface becomes too strong. This is not preferable because it causes uneven brightness. When the lower limit of conditional expression (2) is exceeded and the reflectance at the main wavelength of the light beam from the light source on the second polarization separation surface increases, the reflection at the second angle separation surface with respect to the first angle separation surface increases. This is undesirable because the intensity of the light becomes too strong and it appears as uneven brightness when observed with the eyes.

Note that it is preferable that the numerical range of conditional expression (2) be the numerical range of conditional expression (2a) below.

1.00<R2/R1≦3.50 (2a)
It is further preferable that the numerical range of conditional expression (2) be the numerical range of the following conditional expression (2b).

1.10≦R2/R1≦2.50 (2b)
When the light control means includes a first angular separation surface and a second angular separation surface, it is preferable that the image display device of each embodiment satisfies the following conditional expressions (3) and (4).

T1≧0.8 (3)
T2≧0.8 (4)
Here, if the angle at which the principal ray of the luminous flux from the image display element enters the angle separation surface is θ2, then T1 is the angle θ2 from the image display element to the first angle separation surface of the first angle separation surface. It is the transmittance for the incident light beam. T2 is the transmittance of the second angular separation surface to a light flux that is incident on the second angular separation surface from the image display element at an angle θ2.

It is preferable that the numerical ranges of conditional expressions (3) and (4) are the numerical ranges of the following conditional expressions (3a) and (4a).

T1≧0.9 (3a)
T2≧0.9 (4a)
Furthermore, it is more preferable that the numerical ranges of conditional expressions (3) and (4) be the numerical ranges of conditional expressions (3b) and (4b) below.

T1≧0.95 (3b)
T2≧0.95 (4b)
It is preferable that the image display device of each embodiment satisfies the following conditional expression (5).

0.3<d/m≦2.5 (5)
Here, m is the diameter of the reflecting surface that reflects the light flux from the light control means of the image display element. In each embodiment, MEMS is used as an example of the image display element, and in this case, m is the length ( In the case of an elliptical mirror, the long axis or short axis). d is a reflecting surface (in the case of MEMS, the reflecting surface of a mirror with a deflection angle of 0°) and an incident surface on which the light beam from the light control means of the light guide plate enters (in the case where an incident deflecting means is provided, the incident deflecting means) (incident surface). If the value falls below the lower limit of conditional expression (5), the structure will not actually hold, which is not preferable. When the upper limit of conditional expression (5) is exceeded, the light flux that has entered the incident surface of the light guide plate (the incident surface of the incident deflecting means if an incident deflecting means is provided) is emitted from the incident surface again as unnecessary light. , the light utilization efficiency decreases.

Note that it is preferable that the numerical range of conditional expression (5) be the numerical range of conditional expression (5a) below.

0.4≦d/m≦1.8 (5a)
Furthermore, it is more preferable that the numerical range of conditional expression (5) be the numerical range of conditional expression (5b) below.

0.5≦d/m≦1.5 (5b)
It is preferable that the image display device of each embodiment satisfies the following conditional expression (6).

0.05<v/u≦0.60 (6)
Here, u and v are the length of the major axis and the length of the minor axis of the distribution of the luminous flux emitted from the light source, respectively. The range of luminous flux distribution is defined as 20% of the peak intensity. If the short axis becomes shorter than the lower limit of conditional expression (6), it becomes a linear light source, which is not realistic. When the length of the minor axis becomes longer than the upper limit of conditional expression (6), the light beam that has entered the incident surface of the light guide plate (or the incident surface of the incident deflecting means if an incident deflecting means is provided) will again become The light is emitted from the incident surface as unnecessary light, reducing light utilization efficiency.

Note that it is preferable that the numerical range of conditional expression (6) be the numerical range of conditional expression (6a) below.

0.10≦v/u≦0.50 (6a)
Furthermore, it is more preferable that the numerical range of conditional expression (6) be the numerical range of conditional expression (6b) below.

0.20≦v/u≦0.45 (6b)
It is preferable that the image display device of each embodiment satisfies the following conditional expression (7).

θ1≧θ2+φ/2 (7)
Here, φ is the deflection angle of the mirror around the y-axis of the MEMS. If conditional expression (7) is not satisfied, a part of the light beam reflected by the MEMS is reflected by the light control means 13, and the light utilization efficiency decreases.

Note that it is preferable that the numerical range of conditional expression (7) be the numerical range of conditional expression (7a) below.

θ1≧θ2+φ (7a)
Furthermore, it is more preferable that the numerical range of conditional expression (7) be the numerical range of conditional expression (7b) below.

θ1≧θ2+1.1×φ (7b)
The disclosure of this embodiment includes the following configurations.

(Configuration 1)
an image display element;
a light control means including an angular separation surface that reflects a light flux from a light source to the image display element and transmits a light flux from the image display element;
and a light guide plate that guides the light flux from the light control means,
When the angle of incidence of the principal ray of the light flux from the light source on the angle separation surface is θ1 [°], and the angle of incidence of the principal ray of the light flux from the image display element on the angle separation plane is θ2 [°],
θ1≧θ2+10
An image display device characterized by satisfying the following conditional expression.
(Configuration 2)
The light control means includes a first angle separation surface and a second angle separation surface, which are provided in order from a side of the light control means close to a surface on which the light beam from the light source enters,
When the reflectance of the first angle separation surface at the main wavelength of the light beam from the light source is R1, and the reflectance of the second angle separation surface at the main wavelength is R2,
1.00<R2/R1≦5.00
The image display device according to configuration 1, which satisfies the following conditional expression.
(Configuration 3)
The light control means includes a first angular separation surface and a second angular separation surface,
T1 is the transmittance of the first angle separation surface at the dominant wavelength from the light source for a light beam that enters the first angle separation surface from the image display element at an angle θ2, and the transmittance of the second angle separation surface is T1. When T2 is the transmittance at the main wavelength for a luminous flux incident on the second angular separation surface from the image display element at an angle θ2,
T1≧0.8
T2≧0.8
The image display device according to configuration 1 or 2, which satisfies the following conditional expression.
(Configuration 4)
The image display element includes a reflective surface that reflects the light beam from the light control means,
When the diameter of the reflective surface is m, and the distance between the reflective surface and the incident surface of the light guide plate on which the light beam from the light control means is incident,
0.3<d/m≦2.5
An image display device according to any one of configurations 1 to 3, characterized in that the following conditional expression is satisfied:
(Configuration 5)
4. The image display device according to configuration 4, wherein the diameter of the reflecting surface is parallel to the direction of the principal ray of the light beam incident on the angle separation surface.
(Configuration 6)
The distribution of the luminous flux from the light source has an elliptical shape, where the length of the major axis of the distribution of the luminous flux from the light source is u, and the length of the minor axis of the distribution of the luminous flux from the light source is v,
0.00<v/u≦0.60
6. The image display device according to claim 1, wherein the image display device satisfies the following conditional expression.
(Configuration 7)
The image display element includes a mirror that swings around an axis parallel to a direction perpendicular to a direction of a principal ray of a light beam incident on the angle separation surface among directions included in the reflection surface,
When the deflection angle of the mirror is φ [°],
θ1≧θ2+φ/2
7. The image display device according to claim 1, wherein the image display device satisfies the following conditional expression.
(Configuration 8)
The distribution of the luminous flux from the light source is elliptical,
According to any one of configurations 1 to 7, the direction parallel to the short axis of the distribution of the light flux from the light source is parallel to the direction in which the light flux from the image display element is directed toward the light guide plate. The image display device described.
(Configuration 9)
The light guide plate includes a first surface, a second surface parallel to and opposite to the first surface, and a third surface connected to the first surface and the second surface,
According to any one of configurations 1 to 8, the light from the light control means enters from the third surface and is totally reflected by each of the first surface and the second surface. image display device.
(Configuration 10)
10. The image display device according to configuration 9, wherein the third surface is orthogonal to the first surface or the second surface.
(Configuration 11)
10. The image display device according to configuration 9, wherein the third surface is bonded to an exit surface of the light control means that emits a luminous flux to the light guide plate.
(Configuration 12)
The image display device according to configuration 1, wherein the light beam from the light source is totally reflected by the angle separation surface and guided to an image display element.
(Configuration 13)
The light guide plate includes a first surface, a second surface parallel to and opposite to the first surface, and a third surface inclined with respect to the first surface,
13. The image display device according to configuration 12, wherein the light from the light control means enters from the third surface and is totally reflected by each of the first surface and the second surface.
(Configuration 14)
the angular separation plane is parallel to and opposite to the third plane;
When the distance between the angular separation surface and the third surface is p [μm],
p≦100
The image display device according to configuration 13, wherein the image display device satisfies the following conditional expression.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.

10, 24, 34, 54, 65 Light guide plate 11, 21, 31, 41, 51, 61 Light source 12, 22, 32, 42, 52, 62 MEMS (image display element)
13, 23, 33, 43, 53, 63, 64 Light control means 13a, 13b, 23a, 23b, 43a, 43b, 43c, 43d, 53a, 63a
Angle separation plane 100, 200, 300, 400, 500, 600 Image display device

Claims (14)

an image display element;
a light control means including an angular separation surface that reflects a light flux from a light source to the image display element and transmits a light flux from the image display element;
and a light guide plate that guides the light flux from the light control means,
When the angle of incidence of the principal ray of the light flux from the light source on the angle separation surface is θ1 [°], and the angle of incidence of the principal ray of the light flux from the image display element on the angle separation plane is θ2 [°],
θ1≧θ2+10
An image display device characterized by satisfying the following conditional expression. The light control means includes a first angle separation surface and a second angle separation surface, which are provided in order from a side of the light control means close to a surface on which the light beam from the light source enters,
When the reflectance of the first angle separation surface at the main wavelength of the light beam from the light source is R1, and the reflectance of the second angle separation surface at the main wavelength is R2,
1.00<R2/R1≦5.00
The image display device according to claim 1, wherein the image display device satisfies the following conditional expression. The light control means includes a first angular separation surface and a second angular separation surface,
T1 is the transmittance of the first angle separation surface at the dominant wavelength from the light source for a light beam that enters the first angle separation surface from the image display element at an angle θ2, and the transmittance of the second angle separation surface is T1. When T2 is the transmittance at the main wavelength for a luminous flux incident on the second angular separation surface from the image display element at an angle θ2,
T1≧0.8
T2≧0.8
The image display device according to claim 1 or 2, which satisfies the following conditional expression. The image display element includes a reflective surface that reflects the light beam from the light control means,
When the diameter of the reflective surface is m, and the distance between the reflective surface and the incident surface of the light guide plate on which the light beam from the light control means is incident,
0.3<d/m≦2.5
The image display device according to claim 1 or 2, wherein the image display device satisfies the following conditional expression. 5. The image display device according to claim 4, wherein the diameter of the reflective surface is parallel to the direction of the principal ray of the light beam incident on the angle separation surface. The distribution of the luminous flux from the light source has an elliptical shape, where the length of the major axis of the distribution of the luminous flux from the light source is u, and the length of the minor axis of the distribution of the luminous flux from the light source is v,
0.05<v/u≦0.60
The image display device according to claim 1 or 2, wherein the image display device satisfies the following conditional expression. The image display element includes a mirror that swings around an axis parallel to a direction perpendicular to a direction of a principal ray of a light beam incident on the angle separation surface among directions included in the reflection surface,
When the deflection angle of the mirror is φ [°],
θ1≧θ2+φ/2
The image display device according to claim 1 or 2, wherein the image display device satisfies the following conditional expression. The distribution of the luminous flux from the light source is elliptical,
The image display device according to claim 1 or 2, wherein a direction parallel to the short axis of the distribution of the light flux from the light source is parallel to a direction in which the light flux from the image display element is directed toward the light guide plate. . The light guide plate includes a first surface, a second surface parallel to and opposite to the first surface, and a third surface connected to the first surface and the second surface,
3. The image display device according to claim 1, wherein the light from the light control means enters from the third surface and is totally reflected by each of the first surface and the second surface. The image display device according to claim 9, wherein the third surface is perpendicular to the first surface or the second surface. 10. The image display device according to claim 9, wherein the third surface is bonded to an exit surface of the light control means that emits a luminous flux to the light guide plate. The image display device according to claim 1, wherein the light beam from the light source is totally reflected by the angle separation surface and guided to an image display element. The light guide plate includes a first surface, a second surface parallel to and opposite to the first surface, and a third surface inclined with respect to the first surface,
13. The image display device according to claim 12, wherein the light from the light control means enters from the third surface and is totally reflected by each of the first surface and the second surface. the angular separation plane is parallel to and opposite to the third plane;
When the distance between the angular separation surface and the third surface is p [μm],
p≦100
The image display device according to claim 13, wherein the image display device satisfies the following conditional expression.