JP2021033252A - Optical member and display device - Google Patents

Abstract

To suppress deterioration in quality of a displayed image while using one base material.SOLUTION: An optical member 10 has a base material 11, a first diffraction optical member 20, a second diffraction optical member 30, and a third diffraction optical member 40. The first diffraction optical member 20 includes a first diffraction optical element 21 and a second diffraction optical element 22. The second diffraction optical member 30 includes a third diffraction optical element 31 and a fourth diffraction optical element 32. The third diffraction optical member 40 includes a fifth diffraction optical element 41 and a sixth diffraction optical element 42. The second diffraction optical member 30 is at a position shifting from the first diffraction optical member 20 in a first direction d1. The third diffraction optical member 40 is at a position shifting from the second diffraction optical member 30 in a second direction d2. In plan view, the first diffraction optical element 21 and the second diffraction optical element 22 are provided at positions shifting in a direction orthogonal to the first direction d1. In plan view, the third diffraction optical element 31 and the fourth diffraction optical element 32 are provided at positions shifting in the direction orthogonal to the first direction d1.SELECTED DRAWING: Figure 2

Description

The present invention relates to an optical member and a display device having an optical member.

A head-mounted display is known as a display device that displays the image light from the display unit in front of the observer's eyes by an optical member. In such a display device, for example, as shown in Patent Document 1 and Patent Document 2, the optical member guides the substrate and the inside of the substrate to guide the image light and the inside of the substrate. It has an incident portion of the image light and a diffractive optical element provided in the emitting portion for emitting the existing image light.

The conditions for diffracting the light incident on the diffractive optical element largely depend on the wavelength of the diffracted light. That is, the diffractive optical element provided to diffract the light of a certain wavelength corresponding to the light of a certain wavelength hardly diffracts the light of another wavelength significantly different from that wavelength. For this reason, a plurality of types of diffractive optical elements corresponding to the wavelengths of the image light to be guided are provided at the incident portion and the exit portion of the optical member. Typically, three types of diffractive optical elements corresponding to light of each wavelength of red, green, and blue are provided.

The light diffracted by the diffracting optical element provided so as to diffract the light of the wavelength in the incident portion of the image light is guided in the base material, and the light of the wavelength is diffracted in the emitting portion of the image light. By being diffracted by another diffractive optical element provided as described above, the image light of that wavelength can be displayed in front of the observer's eyes.

Special Table 2009-186794 Japanese Unexamined Patent Publication No. 2015-102613

Usually, a diffractive optical element intended to diffract light of one wavelength is laminated on a different substrate than another diffractive optical element intended to diffract light of another wavelength. Therefore, when three types of diffractive optical elements are provided, the optical member has three base materials.

Since the base material is expensive, it is desired to use one base material included in the optical member. However, a diffractive optical element corresponding to light having a certain wavelength can also diffract light having a wavelength close to that wavelength. Therefore, if three types of diffractive optical elements corresponding to light of each wavelength of red, green, and blue are provided on one substrate, diffraction corresponding to light of a certain wavelength provided in the incident portion of image light is provided. After the light diffracted by the optical element is guided from the incident part to the emitting part, it is diffracted by a diffracting optical element provided in the emitting part of the image light and corresponding to the light having a wavelength different from the wavelength. There is. Since such light is not diffracted in the intended direction, the light is displayed in a direction different from the intended direction. In other words, some of the colors of the image to be displayed are displayed out of alignment. In this way, if three types of diffractive optical elements are provided on one substrate, the light is diffracted by the diffractive optical elements corresponding to light of different wavelengths, and the quality of the image to be displayed on the display device deteriorates. Resulting in.

The present invention has been made in consideration of such a point, and an object of the present invention is to suppress deterioration of the quality of the displayed image while using only one base material.

The first optical member of the present invention is
With the base material
A first diffractive optical member laminated on the base material and including a first diffractive optical element and a second diffractive optical element,
A second diffractive optical member laminated on the base material at a position deviated from the first diffractive optical member in the first direction and including a plurality of third diffractive optical elements and a plurality of fourth diffractive optical elements.
A third diffractive optical member that is laminated on the substrate at a position deviated from the second diffractive optical member in a second direction that is non-parallel to the first direction, and includes a plurality of fifth diffractive optical elements and a plurality of sixth diffractive optical elements. An optical member including a diffractive optical member.
The first diffracting optical element diffracts the light in the first wavelength region among the light incident on the base material, and the diffracted light in the first wavelength region passes through the base material in the first direction. To be guided
The second diffracting optical element diffracts the light in the second wavelength region different from the first wavelength region among the light incident on the substrate, and the diffracted light in the second wavelength region is the second. The inside of the base material is guided in one direction so as to be guided.
The third diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is guided in the base material in the second direction.
The fourth diffracting optical element diffracts the light in the second wavelength region so that the diffracted light in the second wavelength region is guided in the base material in the second direction.
The fifth diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is emitted from the base material.
The sixth diffracting optical element diffracts the light in the second wavelength region so that the diffracted light in the second wavelength region is emitted from the base material.
In a plan view, the first diffractive optical element and the second diffractive optical element are provided at positions shifted in a direction orthogonal to the first direction.
In a plan view, the third diffractive optical element and the fourth diffractive optical element are provided at positions shifted in a direction orthogonal to the first direction.

In the first optical member of the present invention
In a plan view, the third diffractive optical element and the fourth diffractive optical element are provided at positions shifted in a direction orthogonal to the second direction.
In a plan view, the fifth diffractive optical element and the sixth diffractive optical element may be provided at positions shifted in a direction orthogonal to the second direction.

The second optical member of the present invention is
With the base material
A first diffractive optical member laminated on the base material and including a first diffractive optical element and a second diffractive optical element,
A second diffractive optical member laminated on the base material at a position deviated from the first diffractive optical member in the first direction and including a plurality of third diffractive optical elements and a plurality of fourth diffractive optical elements.
A third diffractive optical member that is laminated on the substrate at a position deviated from the second diffractive optical member in a second direction that is non-parallel to the first direction, and includes a plurality of fifth diffractive optical elements and a plurality of sixth diffractive optical elements. An optical member including a diffractive optical member.
The first diffracting optical element diffracts the light in the first wavelength region among the light incident on the base material, and the diffracted light in the first wavelength region passes through the base material in the first direction. To be guided
The second diffracting optical element diffracts the light in the second wavelength region different from the first wavelength region among the light incident on the substrate, and the diffracted light in the second wavelength region is the second. The inside of the base material is guided in one direction so as to be guided.
The third diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is guided in the base material in the second direction.
The fourth diffracting optical element diffracts the light in the second wavelength region so that the diffracted light in the second wavelength region is guided in the base material in the second direction.
The fifth diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is emitted from the base material.
The sixth diffracting optical element diffracts the light in the second wavelength region so that the diffracted light in the second wavelength region is emitted from the base material.
In a plan view, the third diffractive optical element and the fourth diffractive optical element are provided at positions shifted in a direction orthogonal to the second direction.
In a plan view, the fifth diffractive optical element and the sixth diffractive optical element are provided at positions shifted in a direction orthogonal to the second direction.

The third optical member of the present invention is
With the base material
A first diffractive optical member laminated on the base material and including a first diffractive optical element and a second diffractive optical element,
A second diffractive optical member laminated on the base material at a position deviated from the first diffractive optical member in the first direction and including a plurality of third diffractive optical elements.
A fourth diffractive optical member laminated on the base material at a position deviated from the first diffractive optical member in a second direction parallel to the first direction, and including a fourth diffractive optical element.
A plurality of fifth diffractive optical elements and a plurality of fifth diffractive optical elements are laminated on the base material at a position deviated from the second diffractive optical member in the second direction and deviated from the fourth diffractive optical member in the first direction. An optical member comprising a third diffractive optical member including the sixth diffractive optical element of the above.
The first diffracting optical element diffracts the light in the first wavelength region among the light incident on the base material, and the diffracted light in the first wavelength region passes through the base material in the first direction. To be guided
The second diffracting optical element diffracts the light in the second wavelength region different from the first wavelength region among the light incident on the substrate, and the diffracted light in the second wavelength region is the second. The inside of the base material is guided in two directions so as to be guided.
The third diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is guided in the base material in the second direction.
The fourth diffracting optical element diffracts the light in the second wavelength region so that the diffracted light in the second wavelength region is guided in the base material in the first direction.
The fifth diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is emitted from the base material.
The sixth diffracting optical element diffracts the light in the second wavelength region so that the diffracted light in the second wavelength region is emitted from the base material.

In the first to third optical members of the present invention, the plurality of third diffractive optical elements may be arranged apart from each other in the first direction.

In the first to third optical members of the present invention, the third diffraction optical element, the fourth diffraction optical element, and the sixth diffraction between the two adjacent fifth diffraction optical elements in the second direction. At least one of the optical elements may be arranged.

In the first to third optical members of the present invention, the light transmittance in the second wavelength region of the first diffraction optical element may be 30% or more.

In the first to third optical members of the present invention, the first diffraction optical element and the second diffraction optical element may be volume holograms.

In the first to third optical members of the present invention, the fifth diffraction optical element and the sixth diffraction optical element may be surface relief type holograms.

In the first to third optical members of the present invention, the third diffractive optical element and the fourth diffractive optical element may be a surface relief type hologram.

In the first to third optical members of the present invention, a light-shielding member provided between the fifth diffraction optical element and the sixth diffraction optical element may be further provided.

In the first to third optical members of the present invention
Further provided with a light-shielding member forming a plurality of openings,
The fifth diffractive optical element and the sixth diffractive optical element may be arranged in the opening.

In the first to third optical members of the present invention, the first diffraction optical element, the second diffraction optical element, the third diffraction optical element, the fourth diffraction optical element, the fifth diffraction optical element, and the first diffraction optical element. At least one of the patterns of the diffraction lattice of the 6-diffraction optical element may be formed by the uneven shape.

In the first to third optical members of the present invention, the uneven shape may extend in a direction inclined with respect to the sheet surface of the base material.

In the first to third optical members of the present invention, the first wavelength region may be 600 nm or more and 700 nm or less and 400 nm or more and 490 nm or less.

In the first to third optical members of the present invention, the first wavelength region may be 400 nm or more and 550 nm or less.

The first to third optical members of the present invention are
A protective layer that covers the first diffraction optical member from the side opposite to the base material,
A low refractive index layer provided between the base material and the protective layer may be further provided.

The display device of the present invention
With any of the optics mentioned above
The optical member includes a display unit that is arranged so as to face the first diffraction optical member and emits image light.

In the display device of the present invention, in the display unit, the light in the first wavelength region is incident only on the first diffractive optical element, and the light in the second wavelength region is incident only on the second diffractive optical element. , Image light may be emitted.

In the display device of the present invention
A lens arranged between the optical member and the display unit is further provided.
The minimum size of the first diffractive optical element and the minimum size of the second diffractive optical element in a plan view may be 1/2 or less of the size of the lens.

According to the present invention, it is possible to suppress deterioration of the quality of the displayed image while using only one base material.

FIG. 1 is a perspective view showing a display device arranged in front of the eyes. FIG. 2 is a front view of an optical member included in the display device of FIG. FIG. 3 is a cross-sectional view of the optical member of FIG. 2 along lines III-III. FIG. 4 is a cross-sectional view of an optical element included in the optical member. FIG. 5 is a diagram for explaining the operation of the optical member in the cross-sectional view of the optical member shown in FIG. FIG. 6 is a diagram for explaining the incident of light on the diffractive optical element in the optical member. FIG. 7 is a table showing the ratio of the guided light in the relationship between the number of incidents on the diffraction optical element and the diffraction grating of the diffraction grating. FIG. 8 is a front view showing a modified example of the optical member. FIG. 9 is a front view showing another modified example of the optical member. FIG. 10 is a cross-sectional view of the optical member for explaining a modification of the optical member.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, the scale, aspect ratio, etc. are appropriately changed from those of the actual product and exaggerated for the convenience of illustration and comprehension.

The "sheet surface (plate surface, film surface)" is a target sheet-like member (plate-like) when the target sheet-like (plate-like, film-like) member is viewed as a whole and from a broad perspective. A surface that coincides with the plane direction of a member or film-like member).

In addition, as used in the present specification, the terms such as "parallel", "orthogonal", and "identical" and the values of length and angle that specify the shape and geometric conditions and their degrees are strictly used. Without being bound by meaning, we will interpret it including the range in which similar functions can be expected.

FIG. 1 shows a display device 1 that displays an image in front of the eyes as a head-mounted display as an example of the display device of the present embodiment. The display device 1 guides the display unit 5 that emits image light, the lens 7 that refracts the image light emitted from each position of the display unit 5, and the image light from the incident display unit 5 inside the display unit 5. It has an optical member 10 that emits light from the front of the observer's eyes.

The display unit 5 is a device that emits image light. As the display unit 5, any display unit such as a liquid crystal display, a plasma display, an organic EL display, LCOS, or DLP can be used. The display unit 5 is arranged at a position facing the first diffraction optical member 20 described later of the optical member 10, and emits image light toward the first diffraction optical member 20.

The lens 7 changes the traveling direction by refracting the image light emitted from each position of the display unit 5 for each emission position, and causes the lens 7 to enter the first diffraction optical member 20 of the optical member 10. The lens 7 is typically a collimator that converts the image light into parallel light. The lens 7 is arranged between the display unit 5 and the optical member 10 at a position facing the surface of the display unit 5 that emits image light. The lens 7 is, for example, a convex lens.

The optical member 10 guides the image light inside the optical member 10 and emits the image light from the front of the observer's eyes. When the image light incident on the optical member 10 travels in a substantially parallel direction, the image light emitted from the optical member 10 can be light that travels in a substantially parallel direction. The light incident on the optical member 10 and the light emitted from the optical member 10 are indicated by solid arrows in FIG. 1, and the light guiding the inside of the optical member 10 is indicated by a dotted arrow in FIG. .. As shown in FIG. 1, the light incident on the position facing the display unit 5 of the optical member 10 is guided to the position where the image of the optical member 10 is displayed while changing the traveling direction, and the observer's light is guided. It is emitted from the position where the image in front of the eye is displayed.

The optical member 10 includes a base material 11, a first diffraction optical member 20, a second diffraction optical member 30, a third diffraction optical member 40, and a light-shielding member 70. The first diffraction optical member 20, the second diffraction optical member 30, and the third diffraction optical member 40 are laminated at different positions on the base material 11. More specifically, the second diffractive optical member 30 is laminated on the base material 11 at a position deviated from the first diffractive optical member 20 in the first direction d1. The third diffractive optical member 40 is laminated on the base material 11 at a position deviated from the second diffractive optical member 30 in the second direction d2. The second direction d2 is a direction non-parallel to the first direction d1 and, in the illustrated example, a direction orthogonal to the first direction d1.

Hereinafter, each component of the optical member 10 will be described with reference to FIGS. 2 to 4. FIG. 2 is a front view of the optical member 10. FIG. 3 is a cross-sectional view of the optical member 10 along the line III-III in FIG. FIG. 4 is an example of a cross-sectional view of a diffractive optical element described later included in the optical member 10.

The base material 11 functions as a light guide body that guides light in the optical member 10. The base material 11 is transparent in order to guide visible light. Further, the base material 11 is a plate-shaped member. Light is reflected, especially totally reflected, by a pair of main surfaces of the plate-shaped base material 11 or a diffractive optical member provided on the base material 11, so that the inside of the base material 11 is guided. It is preferable that the refractive index of the base material 11 is sufficiently larger than the refractive index of air or the like outside the optical member 10 so that total reflection is likely to occur on the main surface of the base material 11. Specifically, the refractive index of the base material 11 is preferably 1.50 or more, more preferably 1.55 or more, further preferably 1.6 or more, and 1.7 or more. It is even more preferable that there is 1.8 or more, and most preferably 1.8 or more.

In the present specification, the refractive index means the refractive index for light having a wavelength of 587.6 nm.

The base material 11 is made of a material that is not easily deformed, that is, a material having high rigidity, in order to maintain a shape for guiding light inside the base material 11. Further, the base material 11 appropriately supports the first diffraction optical member 20, the second diffraction optical member 30, and the third diffraction optical member 40 laminated on the base material 11. The base material 11 is, for example, polycarbonate, cycloolefin polymer, acrylic, in consideration of visible light transmission, rigidity, supportability of the first diffraction optical member 20, the second diffraction optical member 30, and the third diffraction optical member 40. It is preferable to use a resin material such as glass or glass. In particular, the resin material is suitable from the viewpoint of weight and brittleness. Further, the base material 11 has a thickness of 0.1 mm or more and 2.0 mm in consideration of visible light transmission and rigidity, supportability of the first diffraction optical member 20, the second diffraction optical member 30, and the third diffraction optical member 40. The thickness is as follows, preferably 0.2 mm or more and 1.0 mm or less, and more preferably 0.3 mm or more and 0.7 mm or less. Further, in order to guide light on the main surface of the base material 11 by total reflection, it is preferable that the main surface of the base material 11 has high flatness. Specifically, in an arbitrary 1 mm square region of the base material 11 in a plan view, the difference between the thickness of the thickest portion and the thickness of the thinnest portion is preferably 5 μm or less, and preferably 2 μm or less. It is more preferably 1 μm or less, and even more preferably 0.5 μm or less.

Transparency means the transmittance at each wavelength when measured within the measurement wavelength range of 380 nm to 780 nm using a spectrophotometer (“UV-3100PC” manufactured by Shimadzu Corporation, JIS K 0115 compliant product). It means that the visible light transmittance specified as the average value of is 80% or more.

The first diffraction optical member 20 diffracts the light incident on the optical member 10. The first diffraction optical member 20 is provided at an incident portion of the optical member 10. The first diffraction optical member 20 faces the display unit 5. The first diffraction optical member 20 includes a first diffraction optical element 21, a second diffraction optical element 22, and a seventh diffraction optical element 23.

The first diffracting optical element 21 diffracts the light in the first wavelength region of the light incident on the base material 11. In other words, the first diffraction optical element 21 is provided so as to diffract the light in the first wavelength region incident from the normal direction of the sheet surface of the base material 11. The first diffracting optical element 21 includes a diffraction grating that diffracts light in the first wavelength region. The light in the first wavelength region diffracted by the first diffracting optical element 21 is guided through the base material 11 in the first direction d1. The direction in which the light is guided in the base material 11 means the traveling direction of light in the base material 11 in the plan view of the base material 11. Therefore, the movement in the thickness direction in the base material 11 is ignored.

The fact that the light in the first wavelength region is diffracted means that the diffraction efficiency with respect to the light of an arbitrary wavelength included in the first wavelength region is 10% or more. Diffraction efficiency can be measured from the difference in transmittance using, for example, a spectrophotometer (“UV-2450” manufactured by Shimadzu Corporation).

The diffraction efficiency of the diffraction grating included in the first diffraction optical element 21 is preferably in an appropriate range. Specifically, the diffraction efficiency of the diffraction grating included in the first diffraction optical element 21 is preferably 50% or less, more preferably 10% or more and 40% or less, and 10% or more and 30% or less. It is more preferably 15% or more and 25% or less. By appropriately setting the diffraction efficiency of the diffraction grating included in the first diffraction optical element 21, more light in the first wavelength region can be guided in the first direction d1.

The second diffracting optical element 22 diffracts the light in the second wavelength region of the light incident on the base material 11. In other words, the second diffraction optical element 22 is provided so as to diffract the light in the second wavelength region incident from the normal direction of the sheet surface of the base material 11. The second diffracting optical element 22 includes a diffraction grating that diffracts light in the second wavelength region. The second wavelength region is a wavelength region different from the first wavelength region. Preferably, the second wavelength region is a wavelength region that does not overlap with the first wavelength region. The light in the second wavelength region diffracted by the second diffracting optical element 22 is guided through the base material 11 in the first direction d1.

The diffraction efficiency of the diffraction grating included in the second diffraction optical element 22 is preferably in an appropriate range. Specifically, the diffraction efficiency of the diffraction grating included in the second diffraction optical element 22 is preferably 50% or less, more preferably 10% or more and 40% or less, and 10% or more and 30% or less. It is more preferably 15% or more and 25% or less. By appropriately setting the diffraction efficiency of the diffraction grating included in the second diffraction optical element 22, more light in the second wavelength region can be guided in the first direction d1.

The seventh diffracting optical element 23 diffracts the light in the third wavelength region of the light incident on the base material 11. In other words, the seventh diffracting optical element 23 is provided so as to diffract the light in the third wavelength region incident from the normal direction of the sheet surface of the base material 11. The seventh diffracting optical element 23 includes a diffraction grating that diffracts light in the third wavelength region. The third wavelength region is a wavelength region different from the first wavelength region and the second wavelength region. Preferably, the third wavelength region is a wavelength region that does not overlap with the first wavelength region and the second wavelength region. The light in the third wavelength region diffracted by the seventh diffracting optical element 23 is guided through the base material 11 in the first direction d1.

The diffraction efficiency of the diffraction grating included in the seventh diffraction optical element 23 is preferably in an appropriate range. Specifically, the diffraction efficiency of the diffraction grating included in the 7th diffraction optical element 23 is preferably 50% or less, more preferably 10% or more and 40% or less, and 10% or more and 30% or less. It is more preferably 15% or more and 25% or less. By appropriately setting the diffraction efficiency of the diffraction grating included in the seventh diffraction optical element 23, more light in the third wavelength region can be guided in the first direction d1.

The first wavelength region is, for example, the wavelength region of blue light, the second wavelength region is the wavelength region of green light, and the third wavelength region is the wavelength region of red light. That is, the first wavelength region is 400 nm or more and 490 nm or less, the second wavelength region is 500 nm or more and 580 nm or less, and the third wavelength region is 600 nm or more and 700 nm or less.

In particular, since the wavelength range of blue light and the wavelength range of green light are close to each other, in a diffractive optical element intended to diffract light in the first wavelength range including the wavelength range of blue light. That is, it is possible that the first diffractive optical element 21 diffracts the light in the second wavelength region including the wavelength region of the green light. Similarly, in a diffractive optical element intended to diffract light in a second wavelength region including a green light wavelength region, that is, in a second diffracting optical element 22, a first wavelength including a blue light wavelength region. It can diffract the light in the region.

The first diffraction optical element 21 can transmit light in the second wavelength region and light in the third wavelength region. Specifically, the transmittance of the light in the second wavelength region and the light in the third wavelength region in the first diffraction optical element 21 is preferably 30% or more, more preferably 50% or more, and 70. It is even more preferably% or more, and even more preferably 90% or more. Similarly, the second diffraction optical element 22 can transmit light in the first wavelength region and light in the third wavelength region. Specifically, the transmittance of the light in the first wavelength region and the light in the third wavelength region in the second diffraction optical element 22 is preferably 30% or more, more preferably 50% or more, and 70. It is even more preferably% or more, and even more preferably 90% or more. Further, the 7th diffraction optical element 23 can transmit light in the first wavelength region and light in the second wavelength region. Specifically, the transmittance of the light in the first wavelength region and the light in the second wavelength region in the second diffraction optical element 22 is preferably 30% or more, more preferably 50% or more, and 70. It is even more preferably% or more, and even more preferably 90% or more.

In order to appropriately inject the image light transmitted through the lens 7 into the first diffractive optical element 21, the second diffractive optical element 22, and the seventh diffractive optical element 23, the first diffractive optical element 21, the second diffractive optical element 22 and the like. The seventh diffraction optical element 23 is preferably smaller than the lens 7. Specifically, the minimum size of the first diffractive optical element 21, the minimum size of the second diffractive optical element 22, and the minimum size of the seventh diffractive optical element 23 in a plan view are 1/2 or less of the size of the lens 7. It is preferably 1/10 or less, more preferably 1/50 or less, and even more preferably 1/100 or less. Here, the size of the lens means the diameter of the lens. Further, the minimum dimensions of the first diffraction optical element 21, the minimum dimensions of the second diffraction optical element 22, and the minimum dimensions of the seventh diffraction optical element 23 in a plan view are preferably 1 μm or more, more preferably 10 μm or more. , More preferably 50 μm or more, and even more preferably 100 μm or more.

As shown in FIG. 2, in a plan view, the first diffractive optical element 21, the second diffractive optical element 22, and the seventh diffractive optical element 23 are positioned at positions orthogonal to the first direction d1. It is provided. In other words, the first diffraction optical element 21, the second diffraction optical element 22, and the seventh diffraction optical element 23 are not arranged along the first direction d1.

The second diffracting optical member 30 diffracts the light diffracted by the first diffracting optical member 20. The second diffraction optical member 30 extends in the first direction d1. The second diffraction optical member 30 includes a plurality of third diffraction optical elements 31, a plurality of fourth diffraction optical elements 32, and a plurality of eighth diffraction optical elements 33.

The third diffracting optical element 31 diffracts the light diffracted by the first diffracting optical element 21. That is, the third diffraction optical element 31 has a diffraction characteristic of diffracting light in the first wavelength region traveling in the base material 11 in the first direction d1. The third diffracting optical element 31 includes a diffraction grating that diffracts light in the first wavelength region. The light in the first wavelength region diffracted by the third diffracting optical element 31 is guided in the base material 11 in the second direction d2.

The fourth diffracting optical element 32 diffracts the light diffracted by the second diffracting optical element 22. That is, the fourth diffraction optical element 32 has a diffraction characteristic of diffracting light in the second wavelength region traveling in the base material 11 in the first direction d1. The fourth diffracting optical element 32 includes a diffraction grating that diffracts light in the second wavelength region. The light in the second wavelength region diffracted by the fourth diffracting optical element 32 is guided in the base material 11 in the second direction d2.

The eighth diffracting optical element 33 diffracts the light diffracted by the seventh diffracting optical element 23. That is, the eighth diffraction optical element 33 has a diffraction characteristic of diffracting light in the third wavelength region traveling in the base material 11 in the first direction d1. The eighth diffracting optical element 33 includes a diffraction grating that diffracts light in the third wavelength region. The light in the third wavelength region diffracted by the eighth diffraction optical element 33 is guided in the base material 11 in the second direction d2.

The diffraction efficiency of the third diffraction optical element 31, the diffraction efficiency of the fourth diffraction optical element 32, and the diffraction efficiency of the eighth diffraction optical element 33 are the diffraction efficiency of the first diffraction optical element 21 and the diffraction efficiency of the second diffraction optical element 22. It is lower than the diffraction efficiency of the 7th diffraction optical element 23. Therefore, for example, only a part of the light in the first wavelength region incident on a certain third diffraction optical element 31 is diffracted, and the inside of the base material 11 is guided in the second direction d2. However, the second diffraction optical member 30 has a longitudinal direction in the first direction d1. The plurality of third diffractive optical elements 31 are arranged apart from each other in the first direction d1 which is the longitudinal direction of the second diffractive optical member 30. Therefore, the light that is not diffracted by a certain third diffracting optical element 31 is then reflected (preferably total internal reflection) on the surfaces of the third diffracting optical element 31 and the base material 11, and is again reflected by another third diffracting optical element. It is incident on the element 31. Similarly, the plurality of fourth diffractive optical elements 32 of the second diffractive optical member 30 are arranged apart from each other in the first direction d1 which is the longitudinal direction. The light that is not diffracted by one fourth diffracting optical element 32 is then reflected (preferably total internal reflection) on the surfaces of the fourth diffracting optical element 32 and the base material 11 and again to another fourth diffracting optical element 32. Incident. Further, the plurality of eighth diffraction optical elements 33 of the second diffraction optical member 30 are arranged apart from each other in the first direction d1 which is the longitudinal direction. The light that has not been diffracted by one of the eighth diffracting optical elements 33 is then reflected (preferably total internal reflection) on the surfaces of the eighth diffracting optical element 33 and the base material 11, and is again reflected by another eighth diffracting optical element 33. Incident.

The diffraction efficiency of the third diffraction optical element 31, the diffraction efficiency of the fourth diffraction optical element 32, and the diffraction efficiency of the eighth diffraction optical element 33 are preferably such that the light traveling in the first direction d1 is provided by the second diffraction optical member 30. It is set to be diffracted by each of the third diffraction optical element 31, the fourth diffraction optical element 32, and the eighth diffraction optical element 33 before passing through the designated position. Further, the diffraction efficiency of the third diffraction optical element 31, the diffraction efficiency of the fourth diffraction optical element 32, and the diffraction efficiency of the eighth diffraction optical element 33 are preferably the third diffraction optics at each position along the first direction d1. The intensity of the light diffracted by the element 31, the fourth diffraction optical element 32, and the eighth diffraction optical element 33 is adjusted to be uniform. The light diffracted by the third diffractive optical element 31, the fourth diffracted optical element 32, and the eighth diffracted optical element 33 is subsequently subjected to the fifth diffracted optical element 41 and the sixth diffracted optical element 42 of the third diffracted optical member 40, which will be described later. And, by being further diffracted by the ninth diffracting optical element 43, it is emitted from the optical member 10 as image light. By diffracting with the third diffraction optical element 31, the fourth diffraction optical element 32, and the eighth diffraction optical element 33, the intensity distribution of the light traveling in the base material 11 along the first direction d1 is made uniform. The intensity distribution of the light incident on the third diffraction optical member 40 along the first direction d1 can be made uniform.

Specifically, the diffraction efficiency of the third diffraction optical element 31, the diffraction efficiency of the fourth diffraction optical element 32, and the diffraction efficiency of the eighth diffraction optical element 33 are the thickness of the base material 11 and the second diffraction optical member 30. It is determined in consideration of the length along the first direction d1 and the like. Further, from the viewpoint of making the intensity distribution of the diffracted light in the third diffraction optical element 31, the fourth diffraction optical element 32 and the eighth diffraction optical element 33 along the first direction d1, the third diffraction optical element 31 The diffraction efficiency, the diffraction efficiency of the fourth diffractive optical element 32, and the diffraction efficiency of the eighth diffractive optical element 33 are low on the side close to the first diffractive optical member 20, and the intensity of the incident light is reduced. It is preferable that the height is higher on the side away from the optics. That is, the diffraction efficiency of the third diffraction optical element 31, the diffraction efficiency of the fourth diffraction optical element 32, and the diffraction efficiency of the eighth diffraction optical element 33 increase as they move away from the first diffraction optical member 20 along the first direction d1. It is preferably higher.

As shown in FIG. 2, in a plan view, the third diffractive optical element 31, the fourth diffractive optical element 32, and the eighth diffractive optical element 33 are provided at positions shifted in a direction orthogonal to the first direction d1. Has been done. In other words, the third diffractive optical element 31, the fourth diffractive optical element 32, and the eighth diffractive optical element 33 are not arranged along the first direction d1. Further, the third diffractive optical element 31, the fourth diffractive optical element 32, and the eighth diffractive optical element 33 are provided at positions shifted in a direction orthogonal to the second direction d2. In other words, the third diffractive optical element 31, the fourth diffractive optical element 32, and the eighth diffractive optical element 33 are not arranged along the second direction d2.

Further, the first diffraction optical element 21, the second diffraction optical element 22, and the seventh diffraction optical element 23 of the first diffraction optical member 20 diffract the light so as to guide the light in the first direction d1, and the second diffraction optical member. The third diffractive optical element 31, the fourth diffracted optical element 32, and the eighth diffracted optical element 33 of 30, diffract the light so as to guide the light in the second direction d2. That is, the light diffracted by the first diffractive optical element 21, the second diffractive optical element 22, and the seventh diffractive optical element 23 of the first diffractive optical member 20 is the second diffractive optical member with respect to the first diffractive optical member 20. The light that travels in the direction in which 30 is provided and is diffracted by the third diffractive optical element 31, the fourth diffractive optical element 32, and the eighth diffractive optical element 33 of the second diffractive optical member 30 is transferred to the second diffractive optical member 30. On the other hand, the process proceeds in the direction in which the third diffraction optical member 40 is provided. In other words, the first diffractive optical element 21, the second diffractive optical element 22, and the seventh diffractive optical element 23 diffract light with respect to the first diffractive optical member 20 in the direction in which the second diffractive optical member 30 is provided. The third diffractive optical element 31, the fourth diffractive optical element 32, and the eighth diffractive optical element 33 are provided in the direction in which the third diffractive optical member 40 is provided with respect to the second diffractive optical member 30. It is provided to diffract light.

The third diffracting optical member 40 diffracts the light diffracted by the second diffracting optical member 30 and emits it from the base material 11. The third diffraction optical member 40 is provided at the exit portion of the optical member 10. The third diffraction optical member 40 is located in front of the observer of the optical member 10. The third diffraction optical member 40 extends in the first direction d1 and the second direction d2. The third diffraction optical member 40 includes a plurality of fifth diffraction optical elements 41, a plurality of sixth diffraction optical elements 42, and a plurality of ninth diffraction optical elements 43.

The fifth diffracting optical element 41 diffracts the light diffracted by the third diffracting optical element 31. That is, the fifth diffraction optical element 41 has a diffraction characteristic of diffracting light in the first wavelength region traveling in the base material 11 in the second direction d2. The fifth diffraction optical element 41 includes a diffraction grating that diffracts light in the first wavelength region. The light in the first wavelength region diffracted by the fifth diffraction optical element 41 is emitted from the base material 11.

The sixth diffracting optical element 42 diffracts the light diffracted by the fourth diffracting optical element 32. That is, the sixth diffraction optical element 42 has a diffraction characteristic of diffracting light in the second wavelength region traveling in the base material 11 in the second direction d2. The sixth diffracting optical element 42 includes a diffraction grating that diffracts light in the second wavelength region. The light in the second wavelength region diffracted by the sixth diffracting optical element 42 is emitted from the base material 11.

The ninth diffracting optical element 43 diffracts the light diffracted by the eighth diffracting optical element 33. That is, the ninth diffraction optical element 43 has a diffraction characteristic of diffracting light in the third wavelength region traveling in the base material 11 in the second direction d2. The ninth diffracting optical element 43 includes a diffraction grating that diffracts light in the third wavelength region. The light in the third wavelength region diffracted by the ninth diffracting optical element 43 is emitted from the base material 11.

The diffraction efficiency of the fifth diffraction optical element 41, the diffraction efficiency of the sixth diffraction optical element 42, and the diffraction efficiency of the ninth diffraction optical element 43 are the diffraction efficiency of the first diffraction optical element 21 and the diffraction efficiency of the second diffraction optical element 22. It is lower than the diffraction efficiency of the 7th diffraction optical element 23. Therefore, for example, only a part of the light in the first wavelength region incident on a certain position of the fifth diffraction optical element 41 is diffracted and emitted from the base material 11. However, the third diffraction optical member 40 extends in the second direction d2. Therefore, the light that is not diffracted at a certain position of the fifth diffractive optical element 41 is then reflected (preferably total internal reflection) on the surfaces of the fifth diffracted optical element 41 and the base material 11, and is again reflected by the fifth diffracted optical element 41. It is incident on the element 41. Similarly, the light that is not diffracted at a certain position of the 6th diffracting optical element 42 is then reflected (preferably total internal reflection) on the surfaces of the 6th diffracting optical element 42 and the base material 11, and is again reflected by the 6th diffracting optical element 42. It is incident on the element 42. Further, the light that is not diffracted at a certain position of the 9th diffracting optical element 43 is then reflected (preferably total internal reflection) on the surfaces of the 9th diffracting optical element 43 and the base material 11, and is again reflected by the 9th diffracting optical element. It is incident on 43.

The diffraction efficiency of the fifth diffraction optical element 41, the diffraction efficiency of the sixth diffraction optical element 42, and the diffraction efficiency of the ninth diffraction optical element 43 are preferably such that the light traveling in the second direction d2 is provided by the third diffraction optical member 40. It is set to be diffracted by the fifth diffraction optical element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43 before passing through the designated positions. Further, the diffraction efficiency of the fifth diffraction optical element 41, the diffraction efficiency of the sixth diffraction optical element 42, and the diffraction efficiency of the ninth diffraction optical element 43 are preferably the fifth diffraction optics at each position along the second direction d2. The intensity of the light diffracted by the element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43 is adjusted to be uniform. The light diffracted by the fifth diffraction optical element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43 is emitted from the optical member 10 as image light. By diffraction by the 5th diffraction optical element 41, the 6th diffraction optical element 42, and the 9th diffraction optical element 43, the intensity distribution of the image light emitted from the optical member 10 along the second direction d2 can be made uniform. ..

Specifically, the diffraction efficiency of the fifth diffraction optical element 41, the diffraction efficiency of the sixth diffraction optical element 42, and the diffraction efficiency of the ninth diffraction optical element 43 are the thickness of the base material 11 and the third diffraction optical member 40. It is determined in consideration of the length along the second direction d2 and the like. Further, from the viewpoint of equalizing the intensity distribution of the diffracted light in the fifth diffraction optical element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43 along the second direction d2, the fifth diffraction optical element 41 The diffraction efficiency, the diffraction efficiency of the sixth diffractive optical element 42, and the diffraction efficiency of the ninth diffractive optical element 43 are low on the side close to the second diffractive optical member 30, and the intensity of the incident light is reduced. It is preferable that the height is higher on the side away from the optics. That is, the diffraction efficiency of the fifth diffraction optical element 41, the diffraction efficiency of the sixth diffraction optical element 42, and the diffraction efficiency of the ninth diffraction optical element 43 increase as they move away from the second diffraction optical member 30 along the second direction d2. It is preferably higher.

As shown in FIG. 2, in a plan view, the fifth diffraction optical element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43 are provided at positions shifted in a direction orthogonal to the second direction d2. Has been done. In other words, the 5th diffraction optical element 41, the 6th diffraction optical element 42, and the 9th diffraction optical element 43 are not arranged along the second direction d2.

1st diffraction optical element 21, 2nd diffraction optical element 22, 3rd diffraction optical element 31, 4th diffraction optical element 32, 5th diffraction optical element 41, 6th diffraction optical element 42, 7th diffraction optical element 23, The 8th diffractive optical element 33 and the 9th diffracting optical element 43 can typically be holograms. As shown in FIG. 4, at least one of the patterns of the diffraction grating of the first to ninth diffraction optical elements is a surface relief type hologram formed by the uneven shape. Light is diffracted by incident light on the pattern of the uneven diffraction grating. In such a diffraction grating pattern, the diffraction efficiency can be easily adjusted by, for example, adjusting the depth and width of the unevenness of the concave-convex shape. Further, the pattern of the uneven diffraction grating can have high diffraction efficiency. Further, the uneven diffraction grating pattern can narrow the wavelength range of the light to be diffracted. In particular, the uneven shape shown in FIG. 4 extends in a direction inclined with respect to the sheet surface of the base material 11. By inclining the concave-convex shape, the traveling direction of the light diffracted by the diffractive optical element can be biased in one direction. The depth, width, and inclination angle of the unevenness of the uneven shape can be appropriately set according to the diffraction direction and the diffraction efficiency of the light to be diffracted.

The surface relief type hologram can be formed, for example, by embossing an uneven shape on one surface of the base material 11.

The first to ninth diffraction optical elements are not limited to the examples shown in FIG. 4, and may be a phase type hologram or an amplitude type hologram. Further, the first to ninth diffraction optical elements may be a reflection type hologram or a transmission type hologram. Further, the first to ninth diffraction optical elements may be volumetric holograms or computer-generated holograms (CGH).

In particular, the first diffraction optical element 21, the second diffraction optical element 22, and the seventh diffraction optical element 23 are preferably volume holograms. On the other hand, the third diffraction optical element 31, the fourth diffraction optical element 32, the eighth diffraction optical element 33, the fifth diffraction optical element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43 are surface relief type holograms. Is preferable. The volume hologram tends to increase the diffraction efficiency of the diffraction grating as compared with the surface relief type hologram. On the other hand, the surface relief type hologram can diffract light in a wider angle range than the volume hologram. Therefore, such first, second, and seventh diffractive optical elements have higher diffraction efficiency of the diffraction lattice than the third to sixth, eighth, and ninth diffractive optical elements, and the third to sixth and sixth diffractive optical elements have higher diffraction efficiencies. The 8th and 9th diffracting optical elements diffract light in a wider angle range than the 1st, 2nd and 7th diffracting optical elements.

Further, as in the example shown in FIG. 3, when the first diffraction optical member 20, the second diffraction optical member 30, and the third diffraction optical member 40 are formed on the surface of the optical member 10, the first to first diffraction optical members are formed. The tri-diffraction optical member guides light together with the base material 11. In order to completely reflect light on the surface of the first to third diffractive optical members, the refractive indexes of the first diffractive optical member 20, the second diffractive optical member 30, and the third diffractive optical member 40 are set outside the optical member 10. It is preferable that the refractive index is sufficiently larger than that of air or the like. Specifically, the refractive index of the first diffraction optical member 20, the second diffraction optical member 30, and the third diffraction optical member 40 is preferably 1.50 or more, and more preferably 1.55 or more. , 1.6 or more, more preferably 1.7 or more, and most preferably 1.8 or more.

In the example shown in FIG. 3, the first diffraction optical member 20, the second diffraction optical member 30, and the third diffraction optical member 40 are provided on the same side of the base material 11. However, these may be provided on one side and the other side of the base material 11. Alternatively, for example, the first diffraction optical member 20 may be provided on both one side and the other side of the base material 11. The diffractive optical element provided on one side of the base material 11 is a reflective hologram, and the diffractive optical element provided on the other side of the base material 11 is a transmissive hologram.

The light-shielding member 70 is provided between the fifth diffraction optical element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43 of the third diffraction optical member 40. The light-shielding member 70 suppresses the light of a specific wavelength from entering the diffractive optical element different from the intended diffractive optical element in the third diffractive optical member 40. As a specific example, the light in the first wavelength region is intended to be incident on the fifth diffraction optical element 41, but the light in the first wavelength region is slightly deviated, and the sixth diffraction optical element 42 Or may go to the 9th diffraction optical element 43. In other words, light in the first wavelength region may be incident on the sixth diffraction optical element 42 and the ninth diffraction optical element 43 near the boundary with the fifth diffraction optical element 41. By providing a light-shielding member 70 between the fifth diffraction optical element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43, the sixth diffraction optical element 42 and the ninth diffraction optical element 43 are provided with a light-shielding member 70. Light in the first wavelength region is incident on the light shielding member 70. Therefore, the light-shielding member 70 suppresses the incident light in the first wavelength region on the sixth diffractive optical element 42 and the ninth diffractive optical element 43.

In the example shown in FIG. 2, a plurality of openings 71 are formed by the light-shielding member 70. The fifth diffraction optical element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43 are arranged in the opening 71. In other words, the light-shielding member 70 partitions the fifth diffraction optical element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43.

Next, the operations of the display device 1 and the optical member 10 will be described with reference to FIG. FIG. 5 shows a cross-sectional view of the optical member 10 shown in FIG. 3 in which the light in the first wavelength region of the light incident from the display unit 5 is displayed in front of the observer's eyes.

First, the display unit 5 emits image light which is diffused light. The emitted image light includes light in the first wavelength region, light in the second wavelength region, and light in the third wavelength region. Typically, the image light includes light in the blue wavelength region, light in the green wavelength region, and light in the red wavelength region.

The image light emitted from the display unit 5 is incident on the lens 7. As shown in FIG. 5, the lens 7 causes the image light to travel in a direction substantially parallel to the diffused light. The image light, which is substantially parallel light, is incident on the first diffraction optical member 20 of the optical member 10.

Of the image light incident on the first diffracting optical member 20, as shown in FIG. 5, the light in the first wavelength region is diffracted by the first diffracting optical element 21. On the other hand, the light in the second wavelength region (not shown) is diffracted by the second diffracting optical element 22, and the light in the third wavelength region is diffracted by the seventh diffracting optical element 23. The light diffracted by the first diffracting optical element 21, the light diffracted by the second diffracting optical element 22, and the light diffracted by the seventh diffracting optical element 23 are on a pair of main surfaces of the base material 11 or on the base material 11. The inside of the base material 11 is guided in the first direction d1 by being totally reflected by the diffractive optical member or the like provided in.

As shown in FIG. 5, the light in the first wavelength region diffracted by the first diffracting optical element 21 of the first diffracting optical member 20 is incident on the second diffracting optical member 30. The light in the first wavelength region incident on the second diffracting optical member 30 is diffracted by the third diffracting optical element 31. The light diffracted by the third diffracting optical element 31 is guided in the base material 11 in the second direction d2. Since the diffraction efficiency of the third diffractive optical element 31 is lower than the diffraction efficiency of the first diffractive optical element 21, only a part of the light in the first wavelength region incident on a certain third diffractive optical element 31 is available. It is diffracted and guided in the base material 11 in the second direction d2. The light that has not been diffracted by a certain third diffracting optical element 31 is then reflected by the surfaces of the third diffracting optical element 31 and the base material 11 and is incident on another third diffracting optical element 31 again.

Similarly, the light in the second wavelength region diffracted by the second diffracting optical element 22 of the first diffracting optical member 20 and the light in the third wavelength region diffracted by the seventh diffracting optical element 23, which are not shown, are the second. It is incident on the 2 diffraction optical member 30. The light in the second wavelength region incident on the second diffracting optical member 30 is diffracted by the fourth diffracting optical element 32, and the light in the third wavelength region is diffracted by the eighth diffracting optical element 33. The diffraction efficiency of the fourth diffraction optical element 32 and the diffraction efficiency of the eighth diffraction optical element 33 are lower than the diffraction efficiency of the second diffraction optical element 22 and the diffraction efficiency of the seventh diffraction optical element 23. Only a part of the light in the second wavelength region incident on the fourth diffraction optical element 32 is diffracted, the inside of the base material 11 is guided in the second direction d2, and the light is incident on a certain eighth diffraction optical element 33. Only a part of the light in the three wavelength regions is diffracted, and the inside of the base material 11 is guided in the second direction d2. The light that is not diffracted at a certain position of the fourth diffracting optical element 32 is then reflected on the surfaces of the fourth diffracting optical element 32 and the base material 11 and is incident on another fourth diffracting optical element 32 again. The light that is not diffracted at a certain position of the eighth diffracting optical element 33 is then reflected on the surfaces of the eighth diffracting optical element 33 and the base material 11 and is incident on another eighth diffracting optical element 33 again.

The diffraction efficiency of the third diffraction optical element 31, the diffraction efficiency of the fourth diffraction optical element 32, and the diffraction efficiency of the eighth diffraction optical element 33 are diffracted by the third diffraction optical element 31 at each position along the first direction d1. The intensity of the light to be generated, the intensity of the light diffracted by the fourth diffraction optical element 32, and the intensity of the light diffracted by the eighth diffraction optical element 33 are adjusted to be uniform. In the present embodiment, the diffraction efficiency of the third diffraction optical element 31, the diffraction efficiency of the fourth diffraction optical element 32, and the diffraction efficiency of the eighth diffraction optical element 33 are the first diffraction optical member 20 along the first direction d1. It becomes higher as it moves away from. Therefore, the intensity distribution of the light diffracted by the third diffracting optical element 31 along the first direction d1, the intensity distribution of the diffracted light of the fourth diffracting optical element 32 along the first direction d1, and the eighth diffraction. The intensity distribution of the light diffracted by the optical element 33 along the first direction d1 is made uniform and incident on the third diffracted optical member 40.

The light in the first wavelength region diffracted by the third diffracting optical element 31 of the second diffracting optical member 30, the light in the second wavelength region diffracted by the fourth diffracting optical element 32, and the light diffracted by the eighth diffracting optical element 33. The light in the third wavelength region is incident on the third diffraction optical member 40. The light in each wavelength region is incident on the third diffraction optical member 40 along the second direction d2.

As shown in FIG. 5, the light in the first wavelength region incident on the third diffracting optical member 40 is diffracted by the fifth diffracting optical element 41. The light diffracted by the fifth diffracting optical element 41 is emitted from the base material 11. On the other hand, the light in the second wavelength region incident on the third diffracting optical member 40 (not shown) is diffracted by the sixth diffracting optical element 42, and the light in the third wavelength region is diffracted by the ninth diffracting optical element 43. Ru. The light diffracted by the 6th diffracting optical element 42 and the 9th diffracting optical element 43 is emitted from the base material 11. The diffraction efficiency of the fifth diffraction optical element 41, the diffraction efficiency of the sixth diffraction optical element 42, and the diffraction efficiency of the ninth diffraction optical element 43 are the diffraction efficiency of the first diffraction optical element 21 and the diffraction efficiency of the second diffraction optical element 22. And because it is lower than the diffraction efficiency of the 7th diffractive optical element 23, only a part of the light incident on a certain position of the 5th diffractive optical element 41, the 6th diffractive optical element 42, and the 9th diffractive optical element 43 Is diffracted and exits from the substrate 11. The light that was not diffracted at a certain position of the 5th diffracting optical element 41, the 6th diffracting optical element 42, and the 9th diffracting optical element 43 is subsequently generated by the 5th diffracting optical element 41, the 6th diffracting optical element 42, and the 9th diffracting optical element 42. It reflects on the surface of the diffractive optical element 43 and is again incident on the fifth diffractive optical element 41, the sixth diffractive optical element 42, and the ninth diffractive optical element 43.

The diffraction efficiency of the fifth diffraction optical element 41 is adjusted so that the intensity of the light diffracted by the fifth diffraction optical element 41 becomes uniform at each position along the second direction d2. In the present embodiment, the diffraction efficiency of the fifth diffractive optical element 41 increases as it is separated from the second diffractive optical member 30 along the second direction d2. Therefore, the intensity distribution of the light diffracted by the fifth diffraction optical element 41 along the second direction d2 is made uniform and emitted from the base material 11.

Similarly, the diffraction efficiency of the sixth diffractive optical element 42 and the diffraction efficiency of the ninth diffractive optical element 43 are the intensity of light diffracted by the sixth diffractive optical element 42 and the ninth diffraction efficiency at each position along the second direction d2. The intensity of the light diffracted by the diffractive optical element 43 is adjusted to be uniform. In the present embodiment, the diffraction efficiency of the 6th diffraction optical element 42 and the diffraction efficiency of the 9th diffraction optical element 43 increase as the distance from the second diffraction optical member 30 increases along the second direction d2. Therefore, the intensity distribution of the light diffracted by the 6th diffractive optical element 42 and the 9th diffracting optical element 43 along the second direction d2 is made uniform and emitted from the base material 11.

The image can be visually recognized by the observer observing the light emitted from the base material 11. The light in the first wavelength region, the light in the second wavelength region, and the light in the third wavelength region emitted by the third diffraction optical member 40 facing the observer's eyes are uniform in the first direction d1 and the second direction d2. Since the light is substantially parallel in intensity, the image can be observed with uniform brightness even if the position of the observer shifts.

The conventional optical member has three base materials corresponding to each diffractive optical element corresponding to red, green, and blue. Therefore, in order to make one base material, it was considered to stack three types of diffractive optical elements corresponding to light of each wavelength of red, green, and blue on the base material. For example, three diffractive optical elements are laminated on a portion facing the display unit. However, as described above, the light diffracted by the diffractive optical element provided in the incident portion of the image light and corresponding to the light having a certain wavelength is the light having a wavelength different from the wavelength provided in the emitting portion of the image light. It may be diffracted by the diffraction optical element corresponding to. Since such light is not diffracted in the intended direction, it deteriorates the quality of the image to be displayed on the display device. In particular, such a phenomenon is likely to occur between diffractive optical elements corresponding to near wavelengths. Specifically, a diffracting optical element corresponding to light having a blue wavelength may also diffract light having a green wavelength close to the blue wavelength. As described above, it has been difficult to make one base material without deteriorating the quality of the displayed image.

On the other hand, in the optical member 10 of the present embodiment, the first diffraction optical element 21 and the second diffraction optical element 22 are provided at positions shifted in a direction orthogonal to the first direction d1 in a plan view. Further, in a plan view, the third diffractive optical element 31 and the fourth diffractive optical element 32 are provided at positions shifted in a direction orthogonal to the first direction d1. Then, the light diffracted by the first diffracting optical element 21 and the second diffracting optical element 22 is guided in the first direction d1. Therefore, the light in the first wavelength region diffracted by the first diffracting optical element 21 does not enter the fourth diffracting optical element 32 intended to diffract the light in the second wavelength region, and is diffracted in the third diffraction. It can be incident on the optical element 31. Similarly, the light in the second wavelength region diffracted by the second diffracting optical element 22 does not enter the third diffracting optical element 31 intended to diffract the light in the first wavelength region, and is diffracted fourth. It can be incident on the optical element 32. That is, even if the light in the first wavelength region and the light in the second wavelength region guide light in the same base material 11, unintended diffraction between the first diffraction optical member 20 and the second diffraction optical member 30. Is unlikely to occur. Therefore, it is possible to suppress deterioration of the quality of the displayed image while using only one base material 11.

Further, in a plan view, the third diffractive optical element 31 and the fourth diffractive optical element 32 are provided at positions shifted in a direction orthogonal to the second direction d2. Further, in a plan view, the fifth diffraction optical element 41 and the sixth diffraction optical element 42 are provided at positions shifted in a direction orthogonal to the second direction d2. Then, the light diffracted by the third diffracting optical element 31 and the fourth diffracting optical element 32 is guided in the second direction d2. Therefore, the light in the first wavelength region diffracted by the third diffracting optical element 31 does not enter the sixth diffracting optical element 42 intended to diffract the light in the second wavelength region, and is diffracted in the fifth diffraction. It can be incident on the optical element 41. Similarly, the light in the second wavelength region diffracted by the fourth diffracting optical element 32 does not enter the fifth diffracting optical element 41, which is intended to diffract the light in the first wavelength region, and is diffracted in the sixth diffraction. It can be incident on the optical element 42. That is, even if the light in the first wavelength region and the light in the second wavelength region guide light in the same base material 11, unintended diffraction between the second diffraction optical member 30 and the third diffraction optical member 40. Is unlikely to occur. Therefore, it is possible to suppress deterioration of the quality of the displayed image while using only one base material 11.

In addition, since the diffractive optical elements are provided at offset positions on the base material 11 in a plan view, the diffractive optical elements are not laminated in the normal direction of the sheet surface of the base material 11. Therefore, the interface between the diffractive optical elements is not formed. Therefore, it is possible to reduce the optical action at the interface such as reflection as compared with the case where the diffractive optical elements are laminated. Since the light that guides the inside of the base material 11 is less likely to be subjected to an unintended optical action, the light can be used efficiently.

Further, the plurality of third diffraction optical elements 31 are arranged apart from each other in the first direction d1. Therefore, the plurality of third diffractive optical elements 31 do not overlap with the plurality of fourth diffractive optical elements 32 in the first direction d1 or the second direction d2, and in the second diffractive optical member 30, the first direction d1 Can be placed throughout. That is, the light in the first wavelength region can be diffracted from the entire second diffracting optical member 30 and guided to the third diffracting optical member 40.

Further, the light transmittance in the second wavelength region of the first diffraction optical element 21 is 30% or more. In other words, light having a wavelength that is not diffracted by the first diffracting optical element 21 can pass through the first diffracting optical element 21. By transmitting light having a wavelength that is not intended to be diffracted, the diffractive optical element is less likely to diffract light having an unintended wavelength. Therefore, deterioration of the quality of the displayed image can be suppressed. Therefore, deterioration of the quality of the displayed image can be suppressed.

Further, the optical member 10 further includes a light-shielding member 70 provided between the fifth diffraction optical element 41 and the sixth diffraction optical element 42. In particular, the fifth diffraction optical element 41 and the sixth diffraction optical element 42 are arranged in the opening 71 formed by the light-shielding member 70. The light-shielding member 70 suppresses the light in the first wavelength region, which is slightly deviated while being guided through the base material 11, from entering the sixth diffractive optical element 42 in the third diffractive optical member 40. This makes it possible to prevent light in the second wavelength region, which is slightly deviated from the direction while being guided through the base material 11, from entering the fifth diffraction optical element 41. That is, unintended diffraction is unlikely to occur in the third diffraction optical member 40. Therefore, deterioration of the quality of the displayed image can be suppressed.

Further, among the patterns of the diffraction lattices of the first diffraction optical element 21, the second diffraction optical element 22, the third diffraction optical element 31, the fourth diffraction optical element 32, the fifth diffraction optical element 41, and the sixth diffraction optical element 42. At least one is formed by the uneven shape. The pattern of the diffraction grating formed by the uneven shape can easily adjust the diffraction efficiency and can have a high diffraction efficiency. Specifically, the diffraction efficiency of each diffractive optical element can be adjusted by adjusting the ratio of the region where the pattern of the diffraction grating is provided and the region where the pattern of the diffraction grating is not provided in each diffractive optical element. In each diffraction optical element, the diffraction efficiency can be increased by increasing the ratio of the region provided with the diffraction grating pattern, and the diffraction efficiency can be increased by increasing the ratio of the region not provided with the diffraction grating pattern. Can be lowered. In each diffraction optical element, the region where the pattern of the diffraction grating is not provided may be a flat region where the irregular shape is not provided, or the region where the pattern of the other diffraction grating is formed is provided. It may be an area. In particular, by increasing the diffraction efficiency of the first diffraction optical element 21 and the second diffraction optical element 22, the image light from the display unit 5 can be efficiently diffracted and displayed in front of the observer's eyes. Further, in particular, by adjusting the diffraction efficiency of the third diffraction optical element 31, the fourth diffraction optical element 32, the fifth diffraction optical element 41, and the sixth diffraction optical element 42, the intensity distribution of the image light emitted from the optical member 10 is obtained. Can be homogenized. Specifically, in the third diffraction optical element 31 and the fourth diffraction optical element 32, the closer to the first diffraction optical member 20, the lower the diffraction efficiency, and the farther away from the first diffraction optical member 20, the higher the diffraction efficiency. Therefore, the intensity distribution of the image light emitted from the optical member 10 in the first direction d1 can be made uniform. Further, in the fifth diffraction optical element 41 and the sixth diffraction optical element 42, the closer to the second diffraction optical member 30, the lower the diffraction efficiency, and the farther away from the second diffraction optical member 30, the higher the diffraction efficiency. The intensity distribution of the image light emitted from the optical member 10 in the two directions d2 can be made uniform. Furthermore, the original plate of such an optical member 10 can be easily produced.

In particular, the uneven shape extends in a direction inclined with respect to the sheet surface of the base material 11. In this case, the traveling direction of the light diffracted by the diffracting optical element can be biased in one direction. That is, it is possible to easily diffract the light in the direction of guiding the light. Therefore, light can be used efficiently. Further, the wavelength range of the light diffracted by the uneven shape can be narrowed. Therefore, diffracting light in an unintended wavelength range is effectively suppressed. By making it difficult for unintended diffraction to occur, it is possible to suppress deterioration in the quality of the displayed image.

Further, the image light is incident on the entire lens 7 and is subjected to an optical action on the lens 7. In other words, the image light is emitted from the entire lens 7. If the first diffraction optical element 21, the second diffraction optical element 22, and the seventh diffraction optical element 23 are sufficiently small with respect to the dimensions of the lens 7, the image light transmitted through the lens 7 is transmitted to the first diffraction optical element 21, the second diffraction optical element 21, and the second. It can be appropriately incident on the diffractive optical element 22 and the seventh diffractive optical element 23. Specifically, the minimum size of the first diffractive optical element 21 and the minimum size of the second diffractive optical element 22 in a plan view are 1/2 or less of the size of the lens 7, preferably 1/10 or less. That is, more preferably 1/50 or less, still more preferably 1/100 or less, so that the first diffraction optical element 21, the second diffraction optical element 22, and the seventh diffraction optical element 23 can be easily applied. Can be incident on. Further, since the minimum dimensions of the first diffraction optical element 21, the second diffraction optical element 22, and the seventh diffraction optical element 23 are sufficiently smaller than those of the lens, the first diffraction optical element 21, the second diffraction optical element 22, and the second diffraction optical element 22 Since the 7-diffraction optical element 23 can be dispersed and arranged on the first diffracting optical member 20, the image light incident on the first diffracting optical member 20 can be diffracted without causing unevenness depending on the wavelength. Therefore, the image light can be emitted from the optical member 10 without causing unevenness depending on the wavelength.

If the minimum size of the diffractive optical element is too small, the number of diffraction lattices in the diffractive optical element is reduced, the diffraction efficiency is lowered, and the boundary with other diffractive optical elements is increased. The noise in the optics becomes large and the diffraction efficiency decreases. In particular, if the minimum size of the diffractive optical element is less than 1 μm, the diffraction efficiency of the diffractive optical element is significantly lowered, which is not preferable. Therefore, the minimum size of the diffractive optical element is preferably 1 μm or more, more preferably 10 μm or more, further preferably 50 μm or more, and even more preferably 100 μm or more.

Further, in the first diffraction optical member 20 provided at the incident portion of the optical member 10, the first diffraction optical element 21 and the second diffraction optical element 22 are volume holograms. In the volume hologram, the diffraction efficiency of the diffraction grating can be relatively high. Therefore, the image light incident on the optical member 10 can be efficiently diffracted and used by the first diffraction optical member 20.

On the other hand, in the second diffraction optical member 30 that diffracts the light from the first diffraction optical member 20 to the third diffraction optical member 40, the third diffraction optical element 31 and the fourth diffraction optical element 32 are surface relief type holograms. It has become. The surface relief type hologram can diffract light in a relatively wide angle range in the diffraction grating. That is, even if the angle of the light incident on the diffractive optical element deviates from the intended direction, it is easily diffracted. Therefore, even if the light from the first diffractive optical member 20 deviates from the intended angle and enters the second diffractive optical member 30, the third diffractive optical element 31 and the fourth diffractive optical of the second diffractive optical member 30 It can be diffracted by the element 32. In particular, when the first diffractive optical element 21 and the second diffractive optical element 22 are volume holograms, the diffractive optical element may be deformed from the intended shape at the time of manufacture thereof or the like. The diffraction grating in the deformed diffractive optical element makes it difficult to diffract light in the intended direction. Since the third diffractive optical element 31 and the fourth diffractive optical element 32 are surface relief type holograms, even if the volume hologram is deformed, light deviated from the intended direction is diffracted. Can be used.

Further, in the third diffraction optical member 40 provided at the exit portion of the optical member 10, the fifth diffraction optical element 41 and the sixth diffraction optical element 42 are surface relief type holograms. The surface relief type hologram can diffract light in a relatively wide angle range in the diffraction grating. That is, even if the angle of the light incident on the diffractive optical element deviates from the intended direction, it is easily diffracted. Therefore, even if the light from the second diffractive optical member 30 deviates from the intended angle and enters the third diffractive optical member 40, the fifth diffractive optical element 41 and the sixth diffractive optical of the third diffractive optical member 40 It can be diffracted by the element 42 and emitted from the optical member 10. That is, the image light can be efficiently emitted and used. In particular, when the first diffraction optical element 21 and the second diffraction optical element 22 are volume holograms, the light from the second diffraction optical member 30 tends to deviate from the intended direction. Since the fifth diffractive optical element 41 and the sixth diffracting optical element 42 are surface relief type holograms, light deviated from such an intended direction can be diffracted and used.

Furthermore, the thickness of the volume hologram is sufficiently thicker than the thickness of the surface relief type hologram. Therefore, the first diffraction optical element 21 and the second diffraction optical element 22 are volume holograms, and the third diffraction optical element 31, the fourth diffraction optical element 32, the fifth diffraction optical element 41, and the sixth diffraction optical element 42 are In the surface relief type hologram, the first diffraction optical element 21 and the second diffraction optical element 22 have the third diffraction optical element 31, the fourth diffraction optical element 32, and the fifth diffraction optical element 41 with respect to the base material 11. And it will protrude from the sixth diffraction optical element 42. Therefore, it is difficult for the external member to come into contact with the third diffraction optical element 31, the fourth diffraction optical element 32, the fifth diffraction optical element 41, and the sixth diffraction optical element 42. The volumetric hologram can protect the fine uneven shape of the surface relief type hologram from an external impact. That is, it is possible to prevent the surface relief type hologram from being damaged by the volume hologram.

The diffraction efficiency of the diffraction grating included in the first diffraction optical element 21 and the diffraction efficiency of the diffraction grating included in the second diffraction optical element 22 are preferably in an appropriate range. For example, as shown in FIG. 6, the light diffracted by the diffraction grating in the first diffracting optical element 21 may be totally reflected by the main surface of the base material 11 and then incident on the first diffracting optical element 21 again. is there. The light incident on the first diffracting optical element 21 again can be diffracted again by the diffraction grating of the first diffracting optical element 21. The light diffracted by the diffraction grating again does not go into the base material 11 and is emitted from the optical member 10. Therefore, when the diffraction efficiency of the diffraction grating included in the first diffraction optical element 21 is too high, when the diffraction grating is diffracted a plurality of times, the first diffraction optical member 20 finally becomes the second diffraction optical member 30. The amount of light that is guided is reduced. As confirmed by the present inventors, the light incident from the display unit 5 and diffracted by the diffraction grating in the first diffraction optical element 21 is totally reflected by the main surface of the base material 11 and then about 1 to 5 times. In particular, it was found that the first diffraction optical element 21 was incidentally incident on the first diffraction optical element 21 again four times.

FIG. 7 finally guides the light from the first diffractive optical member 20 to the second diffractive optical member 30 in relation to the diffraction efficiency of the diffraction grating and the number of times it is incident on the diffractive optical element again after being diffracted by the diffraction grating. It is a table which shows the ratio of the light to be made. That is, the ratio of the light guided from the first diffraction optical member 20 to the second diffraction optical member 30 when the light incident from the display unit 5 is 100% is shown. As can be seen from FIG. 7, when the number of times of being diffracted by the diffraction grating once and then incident on the diffraction optical element once or more, the diffraction efficiency of the diffraction grating is preferably 50% or less. Further, when the number of times of being diffracted by the diffraction grating once and then incident on the diffraction optical element again is 3 times or more, the diffraction efficiency of the diffraction grating is preferably 10% or more and 40% or less, and 10% or more and 30% or less. Is more preferable. Further, when the number of times of being diffracted by the diffraction grating once and then incident on the diffraction optical element again is 4 times or more, the diffraction efficiency of the diffraction grating is preferably 15% or more and 25% or less.

As described above, the optical member 10 of the present embodiment includes the base material 11 and the first diffractive optical member 20 which is laminated on the base material 11 and includes the first diffractive optical element 21 and the second diffractive optical element 22. A second diffractive optical member 30 which is laminated on the base material 11 at a position deviated from the first diffractive optical member 20 in the first direction d1 and includes a plurality of third diffractive optical elements 31 and a plurality of fourth diffractive optical elements 32. A plurality of fifth diffractive optical elements 41 and a plurality of sixth diffractive optical elements 42 are laminated on the base material 11 at positions deviated from the second diffractive optical member 30 in the second direction d2, which is non-parallel to the first direction d1. An optical member including a third diffractive optical member 40, wherein the first diffractive optical element 21 diffracts the light in the first wavelength region of the light incident on the base material 11 and is diffracted. The light in the wavelength range is guided through the base material 11 in the first direction d1, and the second diffraction optical element 22 has a second wavelength of the light incident on the base material 11 that is different from the first wavelength range. The light in the region is diffracted so that the diffracted light in the second wavelength region is guided in the base material 11 in the first direction d1, and the third diffraction optical element 31 is the light in the first wavelength region. The diffracted light in the first wavelength region is guided in the base material 11 in the second direction d2, and the fourth diffraction optical element 32 diffracts the light in the second wavelength region. Therefore, the diffracted light in the second wavelength region is guided in the base material 11 in the second direction d2, and the fifth diffraction optical element 41 diffracts the light in the first wavelength region and diffracts it. The light in the first wavelength region is emitted from the base material 11, and the sixth diffraction optical element 42 diffracts the light in the second wavelength region, and the diffracted light in the second wavelength region is the basis. The first diffractive optical element 21 and the second diffractive optical element 22 are provided at positions deviated in a direction orthogonal to the first direction d1 in a plan view so as to emit from the material 11. The third diffractive optical element 31 and the fourth diffractive optical element 32 are provided at positions deviated in a direction orthogonal to the first direction d1. According to such an optical member 10, even if the light in the first wavelength region and the light in the second wavelength region guide light in the same base material 11, the first diffraction optical member 20 and the second diffraction optical member 30 Unintended diffraction is unlikely to occur between and. Therefore, it is possible to suppress deterioration of the quality of the displayed image while using only one base material 11.

Aspects of the present invention are not limited to the individual embodiments described above, but also include various modifications that can be conceived by those skilled in the art, and the effects of the present invention are not limited to the contents described above. That is, various additions, changes and partial deletions are possible without departing from the conceptual idea and purpose of the present invention derived from the contents defined in the claims and their equivalents.

For example, the first diffraction optical element 21, the third diffraction optical element 31, and the fifth diffraction optical element 41 may diffract not only the light in the blue wavelength region but also the light in the red wavelength region. In other words, the first wavelength region may include not only the blue wavelength region but also the red wavelength region. That is, the first wavelength region may be 600 nm or more and 700 nm or less and 400 nm or more and 490 nm or less. In this case, the 7th diffraction optical element 23, the 8th diffraction optical element 33, and the 9th diffraction optical element 43 may not be provided.

Since the blue wavelength range and the red wavelength range are sufficiently separated, even if they are diffracted by the same diffractive optical element, they are diffracted by the diffraction grating corresponding to each wavelength range in the diffractive optical element. It is difficult to diffract in an unintended direction. Therefore, even if the first wavelength region includes the wavelength regions of these two colors, the quality of the image to be displayed on the display device is unlikely to deteriorate.

Alternatively, the first diffraction optical element 21, the third diffraction optical element 31, and the fifth diffraction optical element 41 may diffract not only the light in the blue wavelength region but also the light in the green wavelength region. In other words, the first wavelength region may include not only the blue wavelength region but also the green wavelength region. That is, the first wavelength region may be 400 nm or more and 550 nm or less. In this case, the light in the second wavelength region diffracted by the second diffractive optical element 22, the fourth diffracted optical element 32, and the sixth diffracted optical element 42 is red, and the seventh diffracted optical element 23 and the eighth diffracted optical element 33. And the ninth diffraction optical element 43 may not be provided.

Since the blue wavelength region and the green wavelength region are close to each other, the diffraction grating can be associated with one wavelength region in the diffractive optical element. By diffracting with such a diffraction grating, it is possible to diffract light in the wavelength range of two colors with a diffraction grating corresponding to the same wavelength. Since it is diffracted by the same diffraction grating, it is difficult to diffract in an unintended direction. Therefore, even if the first wavelength region includes the wavelength regions of these two colors, the quality of the image to be displayed on the display device is unlikely to deteriorate.

Further, in the display unit 5, the light in the first wavelength region is incident only on the first diffractive optical element 21, the light in the second wavelength region is incident only on the second diffractive optical element 22, and the light in the third wavelength region is incident on the second diffractive optical element 22. Image light may be emitted so that it is incident only on the seventh diffractive optical element 23. In this case, the image light emitted from the display unit 5 can be efficiently incident on the first diffraction optical element 21, the second diffraction optical element 22, and the seventh diffraction optical element 23. That is, the light from the display unit 5 can be efficiently used.

Further, as shown in FIG. 8, even if the optical member 10 further has a fourth diffraction optical member 50 laminated on the base material 11 at a position deviated from the first diffraction optical member 20 in the second direction d2. Good. In this case, the second diffractive optical member 30 includes the plurality of third diffractive optical elements 31 and the plurality of eighth diffractive optical elements 33, but does not include the fourth diffractive optical element 32. On the other hand, the fourth diffraction optical member 50 includes the fourth diffraction optical element 51.

In the example shown in FIG. 8, the light in the second wavelength region diffracted by the second diffraction optical element 22 is guided in the base material 11 in the second direction d2 and incident on the fourth diffraction optical member 50. .. The light in the second wavelength region incident on the fourth diffracting optical member 50 is diffracted by the fourth diffracting optical element 51. Since the diffraction efficiency of the fourth diffraction optical element 51 is lower than the diffraction efficiency of the first diffraction optical element 21, the diffraction efficiency of the second diffraction optical element 22, and the diffraction efficiency of the seventh diffraction optical element 23, the fourth diffraction efficiency is lower than that of the seventh diffraction optical element 23. Only a part of the light in the second wavelength region incident on the diffraction optical element 51 at a certain position is diffracted, and the inside of the base material 11 is guided in the first direction d1. The light that is not diffracted at a certain position of the fourth diffracting optical element 51 is then reflected on the surfaces of the fourth diffracting optical element 51 and the base material 11 and is incident on the fourth diffracting optical element 51 again.

Also in the example of FIG. 8, the diffraction efficiency of the fourth diffraction optical element 51 is adjusted so that the intensity of the light diffracted by the fourth diffraction optical element 51 becomes uniform at each position along the second direction d2. ing. The diffraction efficiency of the fourth diffractive optical element 32 increases as it is separated from the first diffractive optical member 20 along the second direction d2. Therefore, the intensity distribution of the diffracted light in the fourth diffractive optical element 51 along the second direction d2 is made uniform and incident on the third diffractive optical member 40.

The light in the second wavelength region diffracted by the fourth diffracting optical element 51 is incident on the third diffracting optical member 40 along the first direction d1. On the other hand, the light in the first wavelength region is incident on the third diffraction optical member 40 along the second direction d2, as in the above-described embodiment. In the third diffracting optical member 40, the light in the second wavelength region is diffracted by the sixth diffracting optical element 42 and emitted from the base material 11.

The condition for diffracting the light incident on the diffractive optical element includes not only the wavelength of the diffracted light but also the angle of the light incident on the diffractive optical element. That is, the light incident on the diffractive optical element from the intended direction is easily diffracted, and the light incident on the diffractive optical element from a direction significantly different from the intended direction is hardly diffracted. Specifically, when the diffractive optical element is the above-mentioned surface relief type hologram, light having a traveling direction at a large angle with respect to the extending direction of the concave-convex shape is easily diffracted, and light having a small angle is not easily diffracted. .. For example, light incident on the diffractive optical element from a direction orthogonal to the intended direction, that is, light whose traveling direction is parallel to the extending direction of the concave-convex shape is hardly diffracted.

In this modification, the light in the first wavelength region is incident on the third diffraction optical member 40 along the second direction d2, and the light in the second wavelength region is incident on the third diffraction optical member 40 in the first direction d1. Incident along. The fifth diffractive optical element 41 is provided to diffract the light in the first wavelength region guided in the second direction d2, and the sixth diffracting optical element 42 guides the light in the first direction d1. It is provided to diffract the light in the second wavelength region. For example, when each diffractive optical element is the above-mentioned surface relief type hologram, the concave-convex shape of the fifth diffractive optical element 41 extends in a direction intersecting the second direction d2, and the concave-convex shape of the sixth diffractive optical element 42. Extends in the direction intersecting the first direction d1. Therefore, in the fifth diffractive optical element 41, the light in the second wavelength region guided by the first diffraction d1 is hardly diffracted, and in the sixth diffractive optical element 42, the light in the second diffracted d2 guide is conducted. Light in the wavelength range is hardly diffracted. The direction in which the concave-convex shape of the fifth diffraction optical element 41 extends and the direction in which the concave-convex shape of the sixth diffraction optical element 42 extends are different by 60 ° or more, so that unintended diffraction is less likely to occur, and the difference is 75 ° or more. Unintended diffraction is less likely to occur, and a difference of 85 ° or more makes unintended diffraction less likely to occur. By making unintended diffraction less likely to occur, it is possible to suppress deterioration in the quality of the image to be displayed on the display device.

As shown in FIG. 8, in this modification, in the first diffraction optical member 20, the first diffraction optical element 21 and the second diffraction optical element 22 are provided along the first direction d1 and the second direction d2. And the 7th diffraction optical element 23 may be arranged alternately. In this case, the image light incident on the first diffracting optical member 20 can diffract the light in each wavelength range corresponding to each diffracting optical element in the entire area of the first diffracting optical member 20. Further, in the second diffraction optical member 30, the third diffraction optical element 31 and the fourth diffraction optical element 32 may be alternately arranged along the first direction d1 and the second direction d2. In this case, for example, even if the light in the first wavelength region diffracted by the first diffracting optical member 20 is guided by deviating from the first direction d1, the third diffracting optical element 31 at a position deviated from the second direction d2. Can diffract light in the first wavelength region. Further, in the third diffraction optical member 40, even if the fifth diffraction optical element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43 are alternately arranged along the first direction d1 and the second direction d2. Good. In this case, for example, even if the light in the first wavelength region diffracted by the second diffracting optical member 30 is guided by deviating from the second direction d2, the fifth diffracting optical element 41 at a position deviated from the first direction d1. Can diffract light in the first wavelength region.

Further, as shown in FIG. 8, in this modification, the fifth diffraction optical element 41, the sixth diffraction optical element 42, and the ninth diffraction optical element 43 have openings formed by a grid-like light-shielding member 70. It is arranged in the unit 71. As a result, the incident of light in an unintended wavelength range from the first direction d1 and the second direction d2 can be suppressed, unintended diffraction can be prevented from occurring, and the quality of the image to be displayed on the display device is deteriorated. Can be suppressed.

Further, even if at least one of the third diffraction optical element 31, the fourth diffraction optical element 32, and the sixth diffraction optical element 42 is arranged between the two fifth diffraction optical elements 41 adjacent to each other in the second direction d2. Good. In the example shown in FIG. 9, the third diffraction optical element 31 is arranged between the two fifth diffraction optical elements 41 adjacent to each other in the second direction d2. Similarly, at least one of the third diffraction optical element 31, the fourth diffraction optical element 32, and the fifth diffraction optical element 41 may be arranged between the two sixth diffraction optical elements 42. In the example shown in FIG. 9, the fourth diffractive optical element 32 is arranged between the two sixth diffractive optical elements 42.

Depending on the angle of incidence of the image light from the display unit 5 on the first diffracting optical element 21, the light in the first wavelength region diffracted by the first diffracting optical element 21 deviates from the direction along the first direction d1. It may be guided in the direction. Therefore, the light in the first wavelength region diffracted by the first diffracting optical element 21 is incident on the third diffracting optical element 31 even if the light is guided in a direction deviated from the direction along the first direction d1. be able to. The light in the first wavelength region diffracted by the third diffracting optical element 31 arranged in the direction deviated from the second direction d2 is provided so as to be diffracted in the direction along the second direction d2.

In this way, the light diffracted by the first diffractive optical element 21 and guided in a direction deviated from the direction along the first direction d1 is incident on the third diffractive optical element 31 to bring the light into the first wavelength region. Light can be used efficiently. Further, since the fifth diffraction optical element 41 is arranged between the third diffraction optical elements 31, the light in the first wavelength region diffracted by the fifth diffraction optical element 41 is emitted from the base material 11. Therefore, in the optical member 10, the exit portion from which the image light is emitted can be widened.

In the example shown in FIG. 9, the third diffractive optical element 31 is arranged between the two fifth diffractive optical elements 41. Therefore, the light in the second wavelength region diffracted by the second diffracting optical element 22 and the light in the third wavelength region diffracted by the seventh diffracting optical element 23 are also deviated from the direction along the first direction d1. Even if the light is guided to the fourth diffractive optical element 32, it can be incident on the eighth diffractive optical element 33. Therefore, the light in the second wavelength region and the light in the third wavelength region can also be efficiently used. Further, since the sixth diffraction optical element 42 is arranged between the fourth diffraction optical elements 32 and the ninth diffraction optical element 43 is arranged between the eighth diffraction optical elements 33, the optical member 10 has the ninth diffraction optical element 43. The exit portion from which the image light is emitted can be widened.

When the first wavelength region and the third wavelength region are sufficiently separated from each other, the light in the third wavelength region is hardly diffracted by the diffractive optical element that diffracts the light in the first wavelength region, and the light in the third wavelength region is not diffracted. The light in the first wavelength region is hardly diffracted by the diffractive optical element that diffracts the light. Therefore, when the first wavelength region and the third wavelength region are sufficiently separated from each other, the light in the third wavelength region and the third diffracting optical element 31 that diffracts the light in the first wavelength region are shown as in the example shown in FIG. The eighth diffraction optical element 33 that diffracts the light may be arranged along the first direction d1.

Further, the optical member 10 may have a protective layer 17 that covers the first diffraction optical member 20 from the side opposite to the base material 11. As in the example shown in FIG. 10, the protective layer 17 covers not only the first diffraction optical member 20, but also the second diffraction optical member 30 and the third diffraction optical member 40 from the side opposite to the base material 11. Is preferable. Such a protective layer 17 can protect the diffractive optical element of each diffractive optical member that covers the diffractive optical member and prevent the diffractive optical element from being damaged. The protective layer 17 has sufficient strength to protect the diffractive optical element. The protective layer 17 is made of, for example, polycarbonate, acrylic resin, cycloolefin polymer, polyethylene terephthalate (PET) or the like, and is particularly preferably made of polycarbonate, acrylic resin, cycloolefin polymer or the like which is a material having a small birefringence. Further, if the protective layer 17 is too thin, the rigidity of the protective layer 17 becomes low, so that the protective layer 17 may be deformed when an external force is applied to the optical member 10. On the other hand, if the protective layer 17 is too thick, when heat is applied to the optical member 10, the protective layer 17 is deformed so as to be greatly warped. In order to suppress such deformation of the protective layer 17, the thickness of the protective layer 17 is preferably in an appropriate range. Specifically, the thickness of the protective layer 17 is preferably, for example, 0.2 mm or more and 3 mm or less, and more preferably 0.4 mm or more and 1.5 mm or less. Further, in order to improve the surface strength of the optical member 10, the protective layer 17 is preferably hard-coated.

When such a protective layer 17 is in contact with the diffractive optical member, the light guiding the inside of the base material may be incident on the protective layer 17 from the diffractive optical member. In order to properly guide the light incident on the protective layer 17, it is required to flatten the protective layer 17. However, a protective layer having sufficient flatness is difficult to manufacture, and even if it is manufactured, it is costly. When the light guiding the inside of the base material is incident on the protective layer 17 having low flatness, the light is not properly guided in the protective layer 17, and the image displayed on the display device is deteriorated. Therefore, it has been considered that the protective layer is provided at a position separated from the diffractive optical member, and an air layer is provided between the diffractive optical member and the protective layer. However, if an air layer is provided between the diffractive optical member and the protective layer, the entire optical member becomes thick. It is also difficult to properly provide an air layer.

Therefore, as shown in FIG. 10, it was considered to provide the low refractive index layer 18 between the base material 11 and the protective layer 17. That is, the optical member 10 further has a low refractive index layer 18 in addition to the protective layer 17. The low refractive index layer 18 is made of a material having a lower refractive index than the base material 11. The difference in refractive index between the low refractive index layer 18 and the base material 11 is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.3 or more. The refractive index of the low refractive index layer 18 is, for example, 1.4 or less, preferably 1.3 or less, and more preferably 1.2 or less. The thickness of the low refractive index layer 18 is, for example, 0.01 μm or more and 10 μm or less, preferably 0.1 μm or more and 5 μm or less. Such a low refractive index layer 18 can be easily formed by coating, for example, any of fluororesin, epoxy resin, urethane resin, acrylic resin, hollow silica, and a mixture thereof on the base material 11 and the diffractive optical member. Can be made. In particular, the material of the low refractive index layer 18 is preferably made of a fluororesin or hollow silica having a particularly low refractive index. Further, by producing the low refractive index layer 18 in this way, it is difficult to apply pressure to the diffractive optical member, and therefore it is possible to prevent the diffractive optical member from being distorted by the low refractive index layer 18.

1 Display device 5 Display unit 7 Lens 10 Optical member 11 Base material 17 Protective layer 18 Low refractive index layer 20 First diffraction optical member 21 First diffraction optical element 22 Second diffraction optical element 30 Second diffraction optical member 31 Third diffraction Optical element 32 4th diffractive optical element 40 3rd diffractive optical member 41 5th diffractive optical element 42 6th diffractive optical element 70 Shading member 71 Opening d1 1st direction d2 2nd direction

Claims (20)

With the base material
A first diffractive optical member laminated on the base material and including a first diffractive optical element and a second diffractive optical element,
A second diffractive optical member laminated on the base material at a position deviated from the first diffractive optical member in the first direction and including a plurality of third diffractive optical elements and a plurality of fourth diffractive optical elements.
A third diffractive optical member that is laminated on the substrate at a position deviated from the second diffractive optical member in a second direction that is non-parallel to the first direction, and includes a plurality of fifth diffractive optical elements and a plurality of sixth diffractive optical elements. An optical member including a diffractive optical member.
The first diffracting optical element diffracts the light in the first wavelength region among the light incident on the base material, and the diffracted light in the first wavelength region passes through the base material in the first direction. To be guided
The second diffracting optical element diffracts the light in the second wavelength region different from the first wavelength region among the light incident on the substrate, and the diffracted light in the second wavelength region is the second. The inside of the base material is guided in one direction so as to be guided.
The third diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is guided in the base material in the second direction.
The fourth diffracting optical element diffracts the light in the second wavelength region so that the diffracted light in the second wavelength region is guided in the base material in the second direction.
The fifth diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is emitted from the base material.
The sixth diffracting optical element diffracts the light in the second wavelength region so that the diffracted light in the second wavelength region is emitted from the base material.
In a plan view, the first diffractive optical element and the second diffractive optical element are provided at positions shifted in a direction orthogonal to the first direction.
In a plan view, the third diffractive optical element and the fourth diffractive optical element are optical members provided at positions shifted in a direction orthogonal to the first direction. In a plan view, the third diffractive optical element and the fourth diffractive optical element are provided at positions shifted in a direction orthogonal to the second direction.
The optical member according to claim 1, wherein the fifth diffraction optical element and the sixth diffraction optical element are provided at positions shifted in a direction orthogonal to the second direction in a plan view. With the base material
A first diffractive optical member laminated on the base material and including a first diffractive optical element and a second diffractive optical element,
A second diffractive optical member laminated on the base material at a position deviated from the first diffractive optical member in the first direction and including a plurality of third diffractive optical elements and a plurality of fourth diffractive optical elements.
A third diffractive optical member that is laminated on the substrate at a position deviated from the second diffractive optical member in a second direction that is non-parallel to the first direction, and includes a plurality of fifth diffractive optical elements and a plurality of sixth diffractive optical elements. An optical member including a diffractive optical member.
The first diffracting optical element diffracts the light in the first wavelength region among the light incident on the base material, and the diffracted light in the first wavelength region passes through the base material in the first direction. To be guided
The second diffracting optical element diffracts the light in the second wavelength region different from the first wavelength region among the light incident on the substrate, and the diffracted light in the second wavelength region is the second. The inside of the base material is guided in one direction so as to be guided.
The third diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is guided in the base material in the second direction.
The fourth diffracting optical element diffracts the light in the second wavelength region so that the diffracted light in the second wavelength region is guided in the base material in the second direction.
The fifth diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is emitted from the base material.
The sixth diffracting optical element diffracts the light in the second wavelength region so that the diffracted light in the second wavelength region is emitted from the base material.
In a plan view, the third diffractive optical element and the fourth diffractive optical element are provided at positions shifted in a direction orthogonal to the second direction.
In a plan view, the fifth diffraction optical element and the sixth diffraction optical element are optical members provided at positions shifted in a direction orthogonal to the second direction. With the base material
A first diffractive optical member laminated on the base material and including a first diffractive optical element and a second diffractive optical element,
A second diffractive optical member laminated on the base material at a position deviated from the first diffractive optical member in the first direction and including a plurality of third diffractive optical elements.
A fourth diffractive optical member laminated on the base material at a position deviated from the first diffractive optical member in a second direction parallel to the first direction, and including a fourth diffractive optical element.
A plurality of fifth diffractive optical elements and a plurality of fifth diffractive optical elements are laminated on the base material at a position deviated from the second diffractive optical member in the second direction and deviated from the fourth diffractive optical member in the first direction. An optical member comprising a third diffractive optical member including the sixth diffractive optical element of the above.
The first diffracting optical element diffracts the light in the first wavelength region among the light incident on the base material, and the diffracted light in the first wavelength region passes through the base material in the first direction. To be guided
The second diffracting optical element diffracts the light in the second wavelength region different from the first wavelength region among the light incident on the substrate, and the diffracted light in the second wavelength region is the second. The inside of the base material is guided in two directions so as to be guided.
The third diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is guided in the base material in the second direction.
The fourth diffracting optical element diffracts the light in the second wavelength region so that the diffracted light in the second wavelength region is guided in the base material in the first direction.
The fifth diffracting optical element diffracts the light in the first wavelength region so that the diffracted light in the first wavelength region is emitted from the base material.
The sixth diffracting optical element is an optical member that diffracts light in the second wavelength region so that the diffracted light in the second wavelength region is emitted from the base material. The optical member according to any one of claims 1 to 4, wherein the plurality of third diffraction optical elements are arranged apart from each other in the first direction. The claim that at least one of the third diffraction optical element, the fourth diffraction optical element, and the sixth diffraction optical element is arranged between the two fifth diffraction optical elements adjacent to each other in the second direction. The optical member according to any one of 1 to 5. The optical member according to any one of claims 1 to 6, wherein the light transmittance in the second wavelength region of the first diffraction optical element is 30% or more. The optical member according to any one of claims 1 to 7, wherein the first diffraction optical element and the second diffraction optical element are volume holograms. The optical member according to any one of claims 1 to 8, wherein the fifth diffraction optical element and the sixth diffraction optical element are surface relief type holograms. The optical member according to any one of claims 1 to 9, wherein the third diffraction optical element and the fourth diffraction optical element are surface relief type holograms. The optical member according to any one of claims 1 to 10, further comprising a light-shielding member provided between the fifth diffraction optical element and the sixth diffraction optical element. Further provided with a light-shielding member forming a plurality of openings,
The optical member according to any one of claims 1 to 11, wherein the fifth diffraction optical element and the sixth diffraction optical element are arranged in the opening. At least one of the patterns of the first diffraction optical element, the second diffraction optical element, the third diffraction optical element, the fourth diffraction optical element, the fifth diffraction optical element, and the diffraction lattice of the sixth diffraction optical element. The optical member according to any one of claims 1 to 12, which is formed by a concave-convex shape. The optical member according to claim 13, wherein the uneven shape extends in a direction inclined with respect to the sheet surface of the base material. The optical member according to any one of claims 1 to 14, wherein the first wavelength region is 600 nm or more and 700 nm or less and 400 nm or more and 490 nm or less. The optical member according to any one of claims 1 to 14, wherein the first wavelength region is 400 nm or more and 550 nm or less. A protective layer that covers the first diffraction optical member from the side opposite to the base material,
The optical member according to any one of claims 1 to 16, further comprising a low refractive index layer provided between the base material and the protective layer. The optical member according to any one of claims 1 to 17.
A display device including a display unit that is arranged to face the first diffraction optical member of the optical member and emits image light. The display unit emits image light so that the light in the first wavelength region is incident only on the first diffractive optical element and the light in the second wavelength region is incident only on the second diffractive optical element. The display device according to claim 18. A lens arranged between the optical member and the display unit is further provided.
The display device according to claim 18 or 19, wherein the minimum size of the first diffractive optical element and the minimum size of the second diffractive optical element in a plan view are ½ or less of the size of the lens.

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