JP2023139896A - Lens system and image display device - Google Patents

Abstract

To reduce the occurrence of ring lines when a plurality of lens surfaces are present.SOLUTION: A lens system has at least two lens surfaces, a plurality of concentrically arranged refracting regions are formed in each of the lens surfaces, first refracting regions as the refracting regions are formed in a first lens surface which is at least one of the lens surfaces, second refracting regions as the refracting regions are formed in a second lens surface which is the lens surface different from the first lens surface, and the first refracting regions are formed at a pitch that deviates 4% or more from an integer multiple of the pitch of the second refracting regions when the first refracting regions and the second refracting regions are each arranged on the same optical path.SELECTED DRAWING: Figure 1

Description

The present technology relates to a lens system and an image display device.

Conventionally, in the field of optics, Fresnel lenses having excellent light gathering ability have been used. This Fresnel lens has a plurality of concentric grooves formed therein. The groove refracts and focuses the light. This groove consists of a region that has optical properties and a region that does not have optical properties. Light incident on a region that does not have optical characteristics does not reach the pupil as designed. Therefore, light incident on a region that does not have optical characteristics is visually recognized as a shadow. As a result, a plurality of concentric lines called ring lines are displayed in the visually recognized image. The occurrence of these ring lines leads to deterioration of image quality.

For example, Patent Document 1 discloses a technique for reducing the occurrence of ring lines by changing both the groove pitch and the groove depth depending on the distance from the lens center.

International Publication No. 2020/045518

However, the technique disclosed in Patent Document 1 has room for improvement in reducing the occurrence of ring lines. For example, when grooves are formed on each of multiple lens surfaces, if a single beam of light enters the grooves formed on each lens surface, ring lines due to moiré may occur. . Therefore, in order to reduce the occurrence of ring lines, it is necessary to consider the relative relationship between the groove pitches on each lens surface. Regarding this matter, Patent Document 1 neither describes nor suggests it.

Therefore, the main purpose of the present technology is to provide a lens system and an image display device that reduce the occurrence of ring lines when the lens system has a plurality of lens surfaces.

The present technology has at least two lens surfaces, each of which has a plurality of concentrically arranged refractive regions formed therein, and at least one of the lens surfaces, which is a first lens surface. A first refraction region, which is the refraction region, is formed on the second lens surface, which is the lens surface different from the first lens surface, and a second refraction region, which is the refraction region. and when the first refraction area and the second refraction area are arranged on the same optical path, the first refraction area has a pitch that is an integer of the pitch of the second refraction area. To provide a lens system formed with a pitch that deviates from double by 4% or more.
When each of the first refraction area and the second refraction area is arranged on the same optical path, the minimum integer ratio of the pitch of the first refraction area and the pitch of the second refraction area The common multiple may be 6 or more.
When each of the first refraction area and the second refraction area is arranged on the same optical path, the minimum integer ratio of the pitch of the first refraction area and the pitch of the second refraction area The common multiple may be 30 or more.
The pitch of the refractive regions may be substantially constant on the lens surface.
The pitch of the refraction regions may become shorter from approximately the center of the lens surface toward the outer periphery.
The lens surfaces may be formed on both sides of one Fresnel lens.
The lens surface may be formed into a plurality of Fresnel lenses.
The lens surface may be formed on two Fresnel lenses, and the lens surface may be formed on one side of each Fresnel lens.
The lens surface may be formed on two Fresnel lenses, and the lens surface may be formed on both sides of one of the Fresnel lenses, and the lens surface may be formed on one side of the other Fresnel lens.
The lens surfaces may be formed on two Fresnel lenses, and the lens surfaces may be formed on both surfaces of each Fresnel lens.
The lens surface may be formed into three Fresnel lenses.
Further, the present technology provides an image display device including the lens system.

According to the present technology, it is possible to provide a lens system and an image display device that reduce the occurrence of ring lines when having a plurality of lens surfaces. Note that the effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.

FIG. 1 is a simplified side view showing a configuration example of a lens system 10 according to an embodiment of the present technology. FIG. 1 is a simplified side view showing a configuration example of a lens system 10 according to an embodiment of the present technology. It is an image displayed by a simulation using a comparative example of the lens system 10 according to an embodiment of the present technology. FIG. 3 is a simplified side view showing a configuration example of a lens surface F2 according to an embodiment of the present technology. 1 is a graph showing a design example of a lens system 10 according to an embodiment of the present technology. It is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. It is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. It is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. It is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. FIG. 1 is a simplified side view showing a configuration example of a lens system 10 according to an embodiment of the present technology. It is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. FIG. 12A is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. FIG. 12B is a graph showing a design example of the lens system 10 according to an embodiment of the present technology. FIG. 1 is a simplified side view showing a configuration example of a lens system 10 according to an embodiment of the present technology. It is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. FIG. 15A is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. FIG. 15B is a graph showing a design example of the lens system 10 according to an embodiment of the present technology. FIG. 1 is a simplified side view showing a configuration example of a lens system 10 according to an embodiment of the present technology. It is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. FIG. 18A is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. FIG. 18B is a graph showing a design example of the lens system 10 according to an embodiment of the present technology. FIG. 1 is a simplified side view showing a configuration example of a lens system 10 according to an embodiment of the present technology. FIG. 1 is a simplified side view showing a configuration example of a lens system 10 according to an embodiment of the present technology. 1 is a simplified side view showing a configuration example of an image display device 100 according to an embodiment of the present technology.

Hereinafter, preferred embodiments for implementing the present technology will be described with reference to the drawings. Note that the embodiment described below shows an example of a typical embodiment of the present technology, and the scope of the present technology is not limited thereby. Further, the present technology can be combined with any of the following embodiments and modifications thereof.

In the following description of the embodiments, the configuration may be described using terms including "approximately" such as approximately constant, approximately parallel, and approximately orthogonal. For example, "substantially parallel" does not only mean completely parallel, but also includes substantially parallel, that is, a state deviated from a completely parallel state by, for example, several percent. The same applies to other terms with "omitted". Furthermore, each figure is a schematic diagram and is not necessarily strictly illustrated.

Unless otherwise specified, in the drawings, "above" means the top or upper side of the drawing, "bottom" means the lower or lower side of the drawing, and "left" means the upper side of the drawing. "Right" means the right direction or right side in the figure. Furthermore, in the drawings, the same or equivalent elements or members are denoted by the same reference numerals, and redundant explanations will be omitted.

The explanation will be given in the following order.
1. First embodiment (Example 1 of lens system)
2. Second embodiment (lens system example 2)
3. Third embodiment (lens system example 3)
4. Fourth embodiment (Example 4 of lens system)
5. Fifth embodiment (lens system example 5)
6. Sixth embodiment (example 6 of lens system)
7. Seventh embodiment (example 7 of lens system)
8. Eighth embodiment (example of image display device)

[1. First embodiment (example 1 of lens system)]
The present technology has at least two lens surfaces, each of which has a plurality of concentrically arranged refractive regions formed therein, and at least one of the lens surfaces, which is a first lens surface. A first refraction region, which is the refraction region, is formed on the second lens surface, which is the lens surface different from the first lens surface, and a second refraction region, which is the refraction region. and when the first refraction area and the second refraction area are arranged on the same optical path, the first refraction area has a pitch that is an integer of the pitch of the second refraction area. To provide a lens system formed with a pitch that deviates from double by 4% or more.

A lens system according to an embodiment of the present technology will be described with reference to FIG. 1. FIG. 1 is a simplified side view showing a configuration example of a lens system 10 according to an embodiment of the present technology.

As shown in FIG. 1, the lens system 10 has at least two lens surfaces F1 and F2. A plurality of refraction regions arranged concentrically are formed on each of the lens surfaces F1 and F2. This refraction region refracts incident light. Thereby, the incident light is condensed. The refraction region only needs to have the function of refracting light, and the configuration of the refraction region is not particularly limited. The refractive region may be, for example, a part of a groove in a Fresnel lens or a part of a prism. Below, a configuration example in which the refraction region is a part of a groove in a Fresnel lens will be described.

This refraction region will be explained with reference to FIG. 2. FIG. 2 is a simplified side view showing a configuration example of the lens system 10 according to an embodiment of the present technology. FIG. 2 is an enlarged view of each of the first lens surface F1 and the second lens surface F2 in FIG.

A first refraction region 11 is formed on the first lens surface F1, which is at least one of the lens surfaces F1 and F2. A second refraction region 21 is formed on the second lens surface F2, which is the lens surface different from the first lens surface F1. Each of the first refraction region 11 and the second refraction region 21 refracts light incident from the right side in FIG. Thereby, the light is focused and emitted to the pupil. As a result, the user can visually recognize the image.

As shown in FIG. 2, the first lens surface F1 has a first refractive region 11 that has optical properties and a first non-refractive region 12 that does not have optical properties. are doing. Similarly, the second lens surface F2 has a second refractive region 21 that has optical properties and a second non-refractive region 22 that does not have optical properties. At this time, the light incident on the first non-refraction region 12 or the second non-refraction region 22 that does not have optical characteristics is blocked and may not reach the pupil as designed. Therefore, light incident on this area is visually recognized as a shadow. As a result, illuminance changes occur in the visually recognized image depending on the magnitude of the light shielding. Such a change in illuminance is visually recognized as circular brightness and darkness along each of the first non-refraction area 12 and the second non-refraction area 22, and is therefore called a ring line. Generally, the occurrence of ring lines can be reduced by reducing the area of each of the first non-refractive region 12 and the second non-refractive region 22, which do not have optical characteristics.

However, in a lens system having a plurality of lens surfaces, one beam of light is incident on the first non-refractive area 12 or the second non-refractive area 22 that does not have optical characteristics. There is. At this time, in the image visually recognized by the user, moiré may occur due to regions where shadows overlap and regions where shadows do not overlap, and ring lines may occur. This moiré will be explained with reference to FIG. 3. FIG. 3 is an image displayed by a simulation using a comparative example of the lens system 10 according to an embodiment of the present technology. As shown in FIGS. 3A and 3B, moiré and ring lines are generated. Areas where shadows overlap each other appear relatively bright because the area of the shadows in the image is small. On the other hand, areas where shadows do not overlap each other appear relatively dark because the area of the shadows in the image is large.

In a lens system having a plurality of lens surfaces, in order to reduce the occurrence of ring lines, it is preferable that the pitch of the refractive regions formed on each lens surface be appropriately designed. In the configuration example shown in FIG. 2, the pitch of the first refraction regions 11 formed on the first lens surface F1 and the pitch of the second refraction regions 21 formed on the second lens surface F2 are , is preferably designed appropriately. This pitch will be explained with reference to FIG. 4. FIG. 4 is a simplified side view showing a configuration example of the lens surface F2 according to an embodiment of the present technology.

As shown in FIG. 4, the pitch p is the interval between the grooves made up of the second refraction region 21 and the second non-refraction region 22. In this figure, the height h from the valley to the peak of the groove consisting of the second refraction region 21 and the second non-refraction region 22 is shown.

The relative relationship between the pitch of the first refraction area 11 and the pitch of the second refraction area 21 will be explained with reference to FIG. 5. FIG. 5 is a graph showing a design example of the lens system 10 according to an embodiment of the present technology. The horizontal axis indicates the distance from the center of the lens surface. The vertical axis indicates pitch.

As shown in FIG. 5, the pitch _pF1 of the first refraction region 11 and the pitch _pF2 of the second refraction region 21 become smaller as the distance from the center of the lens surface increases. . The height h _F1 of the first refraction region 11 and the height h _F2 of the second refraction region 21 are approximately constant.

At position P1, the pitch p _F2 of the second refraction regions 21 is approximately twice the pitch p _F1 of the first refraction regions 11 . At position P2, the pitch p _F2 of the second refraction region 21 is approximately one time the pitch p _F1 of the first refraction region 11 . That is, at each of the positions P1 and P2, the pitch _pF2 of the second refraction area 21 is approximately an integral multiple of the pitch _pF1 of the first refraction area 11.

A simulation result of a displayed image when each of the first refraction area 11 and the second refraction area 21 has such a design example will be described with reference to FIG. 6. FIG. 6 is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. A ring line occurs near P1 shown in FIG. 6A. A ring line occurs near P2 shown in FIG. 6B. In other words, in a lens system that has two lens surfaces, when the pitch of the refractive regions formed on one lens surface is approximately an integral multiple of the pitch of the refractive regions formed on the other lens surface. , there is a risk that ring lines may occur. Therefore, it is preferable that the pitch of the refractive regions formed on one lens surface further deviates from a substantially integral multiple of the pitch of the refractive regions formed on the other lens surface. After extensive research, the inventor identified the relative relationship between pitches that suppresses the occurrence of ring lines, and completed the present invention.

FIG. 7 is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. In FIGS. 7A to 7C, the pitch p _F2 of the second refraction region 21 is fixed, and the pitch p _F1 of the first refraction region 11 is varied.

FIG. 7A is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.29 mm and the pitch p _F2 of the second refraction area 21 is 0.30 mm. As shown in this figure, the occurrence of ring lines is reduced. In this configuration example, as calculated by the following formula (1), the first refraction area 11 deviates by 3.3% or more from the integral multiple (1 time) of the pitch _pF2 of the second refraction area 21. It is formed with a pitch.

(p _F2 - p _F1 )/p _F2 ×100=(0.30-0.29)/0.30×100≒3.3 (1)

FIG. 7B is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.30 mm and the pitch p _F2 of the second refraction area 21 is 0.30 mm. As shown in this figure, ring lines are occurring. In this configuration example, the pitch p _F1 of the first refraction region 11 is an integral multiple (one time) of the pitch p _F2 of the second refraction region 21 .

FIG. 7C is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.31 mm and the pitch p _F2 of the second refraction area 21 is 0.30 mm. As shown in this figure, the occurrence of ring lines is reduced. In this configuration example, as calculated by the following formula (2), the first refraction area 11 deviates by 3.3% or more from the integral multiple (1 time) of the pitch _pF2 of the second refraction area 21. It is formed with a pitch.

(p _F1 - p _F2 )/p _F2 ×100=(0.31-0.30)/0.30×100≒3.3 (2)

From the above, when each of the first refraction area 11 and the second refraction area 21 is disposed on the same optical path, the first refraction area 11 is further 4 It is preferable that the pitches deviate from each other by % or more. This will be further explained with reference to FIG. 8. FIG. 8 is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. In FIGS. 8A to 8C, the pitch p _F1 of the first refraction region 11 is fixed, and the pitch p _F2 of the second refraction region 21 is varied.

FIG. 8A is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.25 mm and the pitch p _F2 of the second refraction area 21 is 0.23 mm. As shown in this figure, the occurrence of ring lines is reduced. In this configuration example, as calculated by the following equation (3), the second refraction area 21 has a pitch further deviated by 8% from the integer multiple (1 time) of the pitch _pF1 of the first refraction area 11. It is formed.

(p _F1 - p _F2 )/p _F1 ×100=(0.25-0.23)/0.25×100=8 (3)

FIG. 8B is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.25 mm and the pitch p _F2 of the second refraction area 21 is 0.24 mm. As shown in this figure, the occurrence of ring lines is reduced. In this configuration example, as calculated by the following equation (4), the second refraction region 21 has a pitch further deviated by 4% from an integral multiple (1 time) of the pitch _pF1 of the first refraction region 11. It is formed.

(p _F1 - p _F2 )/p _F1 ×100=(0.25-0.24)/0.25×100=4 (4)

FIG. 8C is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.25 mm and the pitch p _F2 of the second refraction area 21 is 0.25 mm. As shown in this figure, ring lines are occurring. In this configuration example, the pitch p _F2 of the second refraction region 21 is an integral multiple (one time) of the pitch p _F1 of the first refraction region 11 .

FIG. 8D is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.25 mm and the pitch p _F2 of the second refraction area 21 is 0.26 mm. As shown in this figure, the occurrence of ring lines is reduced. In this configuration example, as calculated by the following equation (5), the second refraction area 21 has a pitch further deviated by 4% from an integral multiple (1 time) of the pitch _pF1 of the first refraction area 11. It is formed.

(p _F2 - p _F1 )/p _F1 ×100=(0.26-0.25)/0.25×100=4 (5)

FIG. 8E is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.25 mm and the pitch p _F2 of the second refraction area 21 is 0.27 mm. As shown in this figure, the occurrence of ring lines is reduced. In this configuration example, as calculated by the following equation (6), the second refraction area 21 has a pitch further deviated by 8% from the integral multiple (1 time) of the pitch _pF1 of the first refraction area 11. It is formed.

(p _F2 - p _F1 )/p _F1 ×100=(0.27-0.25)/0.25×100=8 (6)

FIG. 8F is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.25 mm and the pitch p _F2 of the second refraction area 21 is 0.28 mm. As shown in this figure, the occurrence of ring lines is reduced. In this configuration example, as calculated by the following equation (7), the second refraction region 21 has a pitch that is further deviated by 12% from an integral multiple (1 time) of the pitch _pF1 of the first refraction region 11. It is formed.

(p _F2 - p _F1 )/p _F1 ×100=(0.28-0.25)/0.25×100=12 (7)

From the above, when the first refraction area 11 and the second refraction area 21 are arranged on the same optical path, the first refraction area 11 is arranged from an integral multiple of the pitch of the second refraction area 21. Furthermore, when the pitches are deviated by 4% or more, the occurrence of ring lines can be reduced. Thereby, deterioration of image quality can be suppressed.

The above description of the lens system according to the first embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[2. Second embodiment (lens system example 2)]
As described above, when the first refraction area 11 and the second refraction area 21 are arranged on the same optical path, the pitch _pF1 of the first refraction area 11 is equal to the pitch of the second refraction area 21. When p is an integer multiple of _F2 , there is a risk that ring lines will occur. The inventor further discovered that the least common multiple of the integer ratio between the pitch p _F1 of the first refraction region 11 and the pitch p _F2 of the second refraction region 21 influences the occurrence of ring lines. For example, when this integer ratio is 1:2, one third of the shadows will result in areas that overlap and areas that do not overlap with each other. When this integer ratio is 3:4, a quarter shadow will result in areas that overlap and areas that do not overlap each other. As the least common multiple of this integer ratio becomes larger, the area where the shadows overlap with each other and the area where the shadows do not overlap become smaller, and the generation of ring lines is suppressed.

However, if the least common multiple becomes extremely large, such as when this integer ratio is 100:101, for example, one pitch becomes approximately an integer multiple of the other pitch, and there is a risk that ring lines may occur. Therefore, it is preferable that one refraction region is formed at a pitch that is further deviated by 4% or more from an integral multiple of the pitch of the other refraction region.

This will be explained with reference to FIG. 9. FIG. 9 is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. In FIGS. 9A to 9C, the pitch p _F1 of the first refraction region 11 is fixed, and the pitch p _F2 of the second refraction region 21 is varied.

FIG. 9A is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.300 mm and the pitch p _F2 of the second refraction area 21 is 0.200 mm. As shown in this figure, the occurrence of ring lines is reduced. In this configuration example, the integer ratio between the pitch p _F1 of the first refraction region 11 and the pitch p _F2 of the second refraction region 21 is 3:2. The least common multiple of this integer ratio is 6.

FIG. 9B is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.300 mm and the pitch p _F2 of the second refraction area 21 is 0.250 mm. As shown in this figure, the occurrence of ring lines is reduced compared to FIG. 9A. In this configuration example, the integer ratio between the pitch p _F1 of the first refraction region 11 and the pitch p _F2 of the second refraction region 21 is 6:5. The least common multiple of this integer ratio is 30.

FIG. 9C is an image displayed by simulation when the pitch p _F1 of the first refraction area 11 is 0.300 mm and the pitch p _F2 of the second refraction area 21 is 0.255 mm. As shown in this figure, the occurrence of ring lines is reduced compared to FIG. 9B. In this configuration example, the integer ratio between the pitch p _F1 of the first refraction region 11 and the pitch p _F2 of the second refraction region 21 is 20:17. The least common multiple of this integer ratio is 340.

From the above, when the first refraction area 11 and the second refraction area 21 are arranged on the same optical path, the pitch _pF1 of the first refraction area 11 and the pitch of the second refraction area 21 are It is preferable that the least common multiple of the integer ratio of pF2 and _F2 is 6 or more. More preferably, the least common multiple of the integer ratio between the pitch p _F1 of the first refraction region 11 and the pitch p _F2 of the second refraction region 21 is 30 or more. More preferably, the least common multiple of the integer ratio between the pitch p _F1 of the first refraction region 11 and the pitch p _F2 of the second refraction region 21 is 340 or more.

The above description of the lens system according to the second embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[3. Third embodiment (example 3 of lens system)]
Another embodiment of the present technology will be described with reference to FIG. 10. FIG. 10 is a simplified side view showing a configuration example of a lens system 10 according to an embodiment of the present technology.

As shown in FIG. 10, the lens system 10 has at least two lens surfaces F1 and F2. Respective lens surfaces F1 and F2 are formed on both sides of one Fresnel lens 1. At this time, the pitch of the refractive regions formed on each of the lens surfaces F1 and F2 may be approximately constant on each of the lens surfaces F1 and F2, or from approximately the center of each of the lens surfaces F1 and F2 to the outer periphery. It may become shorter as it approaches.

A simulation result of a displayed image when the pitch of the refraction regions formed on each of the lens surfaces F1 and F2 is substantially constant on each of the lens surfaces F1 and F2 will be described with reference to FIG. 11. FIG. 11 is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology.

In FIG. 11A, the pitch _pF1 of the refraction regions formed on the first lens surface F1 is 0.30 mm, and the pitch pF2 of the refraction regions formed on the second lens surface _F2 is 0.30 mm. This is an image displayed by simulation at a certain time. As shown in this figure, ring lines are occurring. In this configuration example, the pitch _pF1 of the refraction regions formed on the first lens surface F1 is an integral multiple (1 time) of the pitch _pF2 of the refraction regions formed on the second lens surface F2. ing.

In FIG. 11B, the pitch _pF1 of the refraction regions formed on the first lens surface F1 is 0.29 mm, and the pitch pF2 of the refraction regions formed on the second lens surface _F2 is 0.32 mm. This is an image displayed by simulation at a certain time. As shown in this figure, the occurrence of ring lines is reduced. In this configuration example, as calculated by the following equation (8), the refraction area formed on the first lens surface F1 is equal to the pitch pF2 of the refraction area formed on the second lens surface _F2 . The pitch is further deviated by 9.3% or more from an integral multiple (1 times).

(p _F2 - p _F1 )/p _F2 ×100=(0.32-0.29)/0.32×100≒9.3 (8)

Simulation results of the displayed image when the pitch of one of the refractive regions formed on each of the lens surfaces F1 and F2 becomes shorter from the approximate center to the outer periphery of each of the lens surfaces F1 and F2. will be explained with reference to FIG. FIG. 12A is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. FIG. 12B is a graph showing a design example of the lens system 10 according to an embodiment of the present technology. The horizontal axis indicates the distance from the center of the lens surface. The vertical axis indicates pitch.

As shown in FIG. 12B, the pitch p _F1 of the refractive regions formed on the first lens surface F1 is approximately constant on the first lens surface F1. On the other hand, the pitch _pF2 of the refractive regions formed on the second lens surface F2 becomes shorter from the approximate center of the second lens surface F2 toward the outer periphery. When the distance becomes 15 mm or more, it becomes approximately constant. With such a design example, as shown in FIG. 12A, the occurrence of ring lines is reduced.

The above description of the lens system according to the third embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[4. Fourth embodiment (Example 4 of lens system)]
Another embodiment of the present technology will be described with reference to FIG. 13. FIG. 13 is a simplified side view showing a configuration example of the lens system 10 according to an embodiment of the present technology.

As shown in FIG. 13, the lens system 10 has at least two lens surfaces F1 and F2. Each lens surface F1, F2 is formed into a plurality of Fresnel lenses. In this configuration example, respective lens surfaces F1 and F2 are formed in two Fresnel lenses 1 and 2. Lens surfaces F1 and F2 are formed on one side of each Fresnel lens 1 and 2. A first lens surface F1 is formed on one side of the first Fresnel lens 1. A second lens surface F2 is formed on one side of the second Fresnel lens 2. At this time, the pitch of the refractive regions formed on each of the lens surfaces F1 and F2 may be approximately constant on each of the lens surfaces F1 and F2, or from approximately the center of each of the lens surfaces F1 and F2 to the outer periphery. It may become shorter as it approaches.

A simulation result of a displayed image when the pitch of the refraction regions formed on each of the lens surfaces F1 and F2 is substantially constant on each of the lens surfaces F1 and F2 will be described with reference to FIG. 14. FIG. 14 is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology.

In FIG. 14A, the pitch _pF1 of the refraction regions formed on the first lens surface F1 is 0.30 mm, and the pitch pF2 of the refraction regions formed on the second lens surface _F2 is 0.30 mm. This is an image displayed by simulation at a certain time. As shown in this figure, ring lines are occurring. In this configuration example, the pitch _pF1 of the refraction regions formed on the first lens surface F1 is an integral multiple (1 time) of the pitch _pF2 of the refraction regions formed on the second lens surface F2. ing.

In FIG. 14B, the pitch _pF1 of the refraction regions formed on the first lens surface F1 is 0.30 mm, and the pitch pF2 of the refraction regions formed on the second lens surface _F2 is 0.55 mm. This is an image displayed by simulation at a certain time. As shown in this figure, the occurrence of ring lines is reduced. In this configuration example, as calculated by the following equation (9), the refraction area formed on the first lens surface F1 is equal to the pitch pF2 of the refraction area formed on the second lens surface _F2 . The pitch is further deviated by 9% or more from an integral multiple (twice).

(p _F1 ×2-p _F2 )/p _F2 ×100=(0.60-0.55)/0.55×100≒9...(9)

Simulation results of the displayed image when the pitch of one of the refractive regions formed on each of the lens surfaces F1 and F2 becomes shorter from the approximate center to the outer periphery of each of the lens surfaces F1 and F2. will be explained with reference to FIG. FIG. 15A is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. FIG. 15B is a graph showing a design example of the lens system 10 according to an embodiment of the present technology. The horizontal axis indicates the distance from the center of the lens surface. The vertical axis indicates pitch.

As shown in FIG. 15B, the pitch _pF1 of the refraction regions formed on the first lens surface F1 and the pitch _pF2 of the refraction regions formed on the second lens surface F2 are It becomes shorter from the approximate center of the surfaces F1 and F2 toward the outer periphery. With such a design example, as shown in FIG. 15A, the occurrence of ring lines is reduced.

The above description of the lens system according to the fourth embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[5. Fifth embodiment (example 5 of lens system)]
Another embodiment of the present technology will be described with reference to FIG. 16. FIG. 16 is a simplified side view showing a configuration example of the lens system 10 according to an embodiment of the present technology.

As shown in FIG. 16, the lens system 10 has at least three lens surfaces F1, F2, and F3. Each lens surface F1, F2, F3 is formed into a plurality of Fresnel lenses. In this configuration example, the respective lens surfaces F1, F2, and F3 are formed in two Fresnel lenses 1 and 2. Lens surfaces F1 and F2 are formed on both surfaces of one Fresnel lens 1. A lens surface F3 is formed on one side of the other Fresnel lens 2. At this time, the pitch of the refractive regions formed on each of the lens surfaces F1, F2, and F3 may be approximately constant on each of the lens surfaces F1, F2, and F3, or the pitch of the refractive regions formed on each of the lens surfaces F1, F2, and The length may become shorter as it goes from the approximate center to the outer periphery.

Refer to FIG. 17 for simulation results of displayed images when the pitch of the refraction regions formed on each of lens surfaces F1, F2, and F3 is approximately constant on each of lens surfaces F1, F2, and F3. I will explain. FIG. 17 is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology.

In FIG. 17A, the pitch _pF1 of the refraction regions formed on the first lens surface F1 is 0.30 mm, and the pitch pF2 of the refraction regions formed on the second lens surface _F2 is 0.28 mm. This is an image displayed by simulation when the pitch _pF3 of the refractive regions formed on the third lens surface F3 is 0.28 mm. As shown in this figure, ring lines are occurring. In this configuration example, the pitch _pF2 of the refraction regions formed on the second lens surface F2 is an integral multiple (1 time) of the pitch _pF3 of the refraction regions formed on the third lens surface F3. ing.

In FIG. 17B, the pitch _pF1 of the refraction regions formed on the first lens surface F1 is 0.30 mm, and the pitch pF2 of the refraction regions formed on the second lens surface _F2 is 0.25 mm. This is an image displayed by simulation when the pitch _pF3 of the refractive regions formed on the third lens surface F3 is 0.27 mm. As shown in this figure, the occurrence of ring lines is reduced. In this configuration example, as calculated by the following equation (10), the refraction area formed on the first lens surface F1 is equal to the pitch pF2 of the refraction area formed on the second lens surface _F2 . The pitch is further deviated by 20% or more from an integral multiple (1 times).

(p _F1 - p _F2 )/p _F2 ×100=(0.30-0.25)/0.25×100=20 (10)

Furthermore, the least common multiple of the integer ratio of the pitch _pF1 of the refraction regions formed on the first lens surface F1 and the pitch _pF2 of the refraction regions formed on the second lens surface F2 is 30. ing.

Furthermore, as calculated by the following equation (11), the refraction area formed on the third lens surface F3 is arranged at a pitch p F2 that is an integral multiple of the refraction area formed on the second lens surface _F2 ( 1 times) by 8% or more.

(p _F3 - p _F2 )/p _F2 ×100=(0.27-0.25)/0.25×100=8 (11)

Displayed when the pitch of any of the refractive regions formed on each of the lens surfaces F1, F2, F3 becomes shorter from the approximate center to the outer periphery of each of the lens surfaces F1, F2, F3. The image simulation results will be explained with reference to FIG. 18. FIG. 18A is an image displayed by a simulation using a configuration example of the lens system 10 according to an embodiment of the present technology. FIG. 18B is a graph showing a design example of the lens system 10 according to an embodiment of the present technology. The horizontal axis indicates the distance from the center of the lens surface. The vertical axis indicates pitch.

As shown in FIG. 18B, the pitch p _F1 of the refractive regions formed on the first lens surface F1 is approximately constant on the first lens surface F1. On the other hand, the pitch _pF2 of the refraction regions formed on the second lens surface F2 and the pitch _pF3 of the refraction regions formed on the third lens surface F3 are respectively different from each other. It becomes shorter from the center toward the outer periphery. With such a design example, as shown in FIG. 18A, the occurrence of ring lines is reduced.

The above description of the lens system according to the fifth embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[6. Sixth embodiment (example 6 of lens system)]
Another embodiment of the present technology will be described with reference to FIG. 19. FIG. 19 is a simplified side view showing a configuration example of a lens system 10 according to an embodiment of the present technology.

As shown in FIG. 19, the lens system 10 has at least four lens surfaces F1, F2, F3, and F4. Each lens surface F1, F2, F3, F4 is formed into a plurality of Fresnel lenses. In this configuration example, respective lens surfaces F1, F2, F3, and F4 are formed in two Fresnel lenses 1 and 2. Lens surfaces F1, F2, F3, and F4 are formed on both surfaces of the Fresnel lenses 1 and 2. Lens surfaces F1 and F2 are formed on both surfaces of the first Fresnel lens 1. Lens surfaces F3 and F4 are formed on both surfaces of the second Fresnel lens 2. At this time, the pitch of the refractive regions formed on each of the lens surfaces F1, F2, F3, and F4 may be approximately constant on each of the lens surfaces F1, F2, F3, and F4, or the pitch of the refractive regions formed on each of the lens surfaces F1, F2, F3, and F4 may be approximately constant. It may become shorter as it goes from the approximate center of each of F2, F3, and F4 toward the outer periphery.

The above description of the lens system according to the sixth embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[7. Seventh embodiment (example 7 of lens system)]
Another embodiment of the present technology will be described with reference to FIG. 20. FIG. 20 is a simplified side view showing a configuration example of the lens system 10 according to an embodiment of the present technology.

As shown in FIG. 20, the lens system 10 has at least five lens surfaces F1, F2, F3, F4, and F5. Each lens surface F1, F2, F3, F4, F5 is formed into a plurality of Fresnel lenses. In this configuration example, three Fresnel lenses 1, 2, and 3 are formed with respective lens surfaces F1, F2, F3, F4, and F5. Lens surfaces F1 and F2 are formed on both surfaces of the first Fresnel lens 1. Lens surfaces F3 and F4 are formed on both surfaces of the second Fresnel lens 2. A lens surface F5 is formed on one surface of the third Fresnel lens 3. At this time, the pitch of the refraction regions formed on each of the lens surfaces F1, F2, F3, F4, and F5 may be approximately constant on each of the lens surfaces F1, F2, F3, F4, and F5, The length may become shorter from the approximate center of each of the lens surfaces F1, F2, F3, F4, and F5 toward the outer periphery.

Note that the number of lens surfaces on which refractive regions are formed and the number of Fresnel lenses having the lens surfaces are not particularly limited.

The above description of the lens system according to the seventh embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

[8. Eighth embodiment (example of image display device)]
The present technology provides an image display device including the lens system 10 according to the first to seventh embodiments. An example of the configuration of this image display device will be described with reference to FIG. 21. FIG. 21 is a simplified side view showing a configuration example of an image display device 100 according to an embodiment of the present technology.

As shown in FIG. 21, the image display device 100 includes the lens system 10 according to the first to seventh embodiments, and an image forming section 20 that emits image light to the lens system 10.

The image forming section 20 forms image light. The image forming section 20 can use micropanels to create images within the image forming section 20. This micro panel may be a self-luminous panel such as a micro LED or a micro OLED. A reflective or transmissive liquid crystal may be used in combination with an LED (Light Emitting Diode) light source, an LD (Laser Diode) light source, or the like with an illumination optical system.

The image light emitted from the image forming section 20 is converted into substantially parallel light by, for example, a projection lens (not shown), and then enters the lens system 10 .

The image display device 100 may be a head mounted display (HMD) that is worn on the user's head. Alternatively, the image display device 100 may be placed at a predetermined location as infrastructure.

The above description of the image display device according to the eighth embodiment of the present technology can be applied to other embodiments of the present technology unless there is a particular technical contradiction.

Note that the embodiments according to the present technology are not limited to the embodiments described above, and various changes can be made without departing from the gist of the present technology.

Further, the present technology can also have the following configuration.
[1]
has at least two lens surfaces,
A plurality of refraction regions arranged concentrically are formed on each of the lens surfaces,
A first refraction area, which is the refraction area, is formed on a first lens surface, which is at least one of the lens surfaces, and
A second refraction region, which is the refraction region, is formed on the second lens surface, which is the lens surface different from the first lens surface, and
When each of the first refraction area and the second refraction area is arranged on the same optical path, the first refraction area further deviates by 4% or more from an integral multiple of the pitch of the second refraction area. A lens system formed with a pitch of
[2]
When each of the first refraction area and the second refraction area is arranged on the same optical path, the minimum integer ratio of the pitch of the first refraction area and the pitch of the second refraction area The common multiple is 6 or more,
The lens system according to [1].
[3]
When each of the first refraction area and the second refraction area is arranged on the same optical path, the minimum integer ratio of the pitch of the first refraction area and the pitch of the second refraction area The common multiple is 30 or more,
The lens system according to [1] or [2].
[4]
the pitch of the refractive regions is substantially constant on the lens surface;
The lens system according to any one of [1] to [3].
[5]
The pitch of the refractive regions becomes shorter from approximately the center of the lens surface toward the outer periphery.
The lens system according to any one of [1] to [4].
[6]
the lens surfaces are formed on both sides of one Fresnel lens;
The lens system according to any one of [1] to [5].
[7]
the lens surface is formed into a plurality of Fresnel lenses;
The lens system according to any one of [1] to [6].
[8]
the lens surface is formed into two Fresnel lenses;
The lens surface is formed on one side of each Fresnel lens,
The lens system according to [7].
[9]
the lens surface is formed into two Fresnel lenses;
The lens surfaces are formed on both sides of one of the Fresnel lenses,
the lens surface is formed on one side of the other Fresnel lens;
The lens system according to [7] or [8].
[10]
the lens surface is formed into two Fresnel lenses;
The lens surfaces are formed on both sides of the Fresnel lenses,
The lens system according to any one of [7] to [9].
[11]
the lens surface is formed into three Fresnel lenses;
The lens system according to any one of [7] to [10].
[12]
An image display device comprising the lens system according to any one of [1] to [11].

10 Lens system 1-3 Fresnel lens F1-F5 Lens surface 11 First refractive area 12 First non-refractive area 21 Second refractive area 22 Second non-refractive area 100 Image display device

Claims (12)

has at least two lens surfaces,
A plurality of refraction regions arranged concentrically are formed on each of the lens surfaces,
A first refraction area, which is the refraction area, is formed on a first lens surface, which is at least one of the lens surfaces, and
A second refraction region, which is the refraction region, is formed on the second lens surface, which is the lens surface different from the first lens surface, and
When each of the first refraction area and the second refraction area is arranged on the same optical path, the first refraction area further deviates by 4% or more from an integral multiple of the pitch of the second refraction area. A lens system formed with a pitch of When each of the first refraction area and the second refraction area is arranged on the same optical path, the minimum integer ratio of the pitch of the first refraction area and the pitch of the second refraction area The common multiple is 6 or more,
A lens system according to claim 1. When each of the first refraction area and the second refraction area is arranged on the same optical path, the minimum integer ratio of the pitch of the first refraction area and the pitch of the second refraction area The common multiple is 30 or more,
A lens system according to claim 1. the pitch of the refractive regions is substantially constant on the lens surface;
A lens system according to claim 1. The pitch of the refractive regions becomes shorter from approximately the center of the lens surface toward the outer periphery.
A lens system according to claim 1. the lens surfaces are formed on both sides of one Fresnel lens;
A lens system according to claim 1. the lens surface is formed into a plurality of Fresnel lenses;
A lens system according to claim 1. the lens surface is formed into two Fresnel lenses;
The lens surface is formed on one side of each Fresnel lens,
A lens system according to claim 7. the lens surface is formed into two Fresnel lenses;
The lens surfaces are formed on both sides of one of the Fresnel lenses,
the lens surface is formed on one side of the other Fresnel lens;
A lens system according to claim 7. the lens surface is formed into two Fresnel lenses;
The lens surfaces are formed on both sides of the Fresnel lenses,
A lens system according to claim 7. the lens surface is formed into three Fresnel lenses;
A lens system according to claim 7. An image display device comprising the lens system according to claim 1.