JP2013250506A - Eyepiece and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an image to be enlarged at a wide angle of field, and obtain the performance for suitable use in a head-mounted display or the like.SOLUTION: An eyepiece includes, in order from an eye point side, a first lens having positive refractive power, a second lens with a convex surface facing the eye point side and having positive refractive power, a third lens with a convex surface facing the eye point side and having positive refractive power, a fourth lens with a concave surface facing an image side and having negative refractive power, and a fifth lens with a convex surface facing the eye point side.

Description

  The present disclosure relates to an eyepiece for enlarging an image (for example, an image displayed on an image display element), a display device suitable for a head mounted display using the eyepiece, and the like.

  Examples of display devices using image display elements include electronic viewfinders and head mounted displays.

Japanese Patent No. 3865906 Japanese Patent No. 3924348 Japanese Patent No. 3454296

  In particular, in a head-mounted display, the eyepiece optical system and the apparatus main body are required to be small and lightweight because the apparatus main body is mounted in front of the eye and used for a long time. However, it is necessary to widen the angle of view in order to create an immersive feeling that is attracted to images and videos. For this reason, there are cases in which glass is used for the eyepiece optical system. In such a case, although a high immersive feeling can be produced, it is necessary to wear a heavy eyepiece optical system and device body in front of the eyes due to the use of glass. ing.

  The eyepiece optical systems described in Patent Document 1 and Patent Document 2 ensure good distortion correction and long eye relief by bending the optical system to increase the optical path length and using a free-form surface as the refracting surface. is there. Since it is a single lens, it is lightweight, and it is characterized by fatigue that is harmful to health even when used for a long time. However, since this eyepiece optical system is basically a single lens, chromatic aberration cannot be improved and it is not suitable for enlarging the image of the image display element. In order to maintain a wide angle of view that is important as a head-mounted display, the image display element itself must be enlarged, and thus there is a concern that the image display element is costly.

  The eyepiece optical system described in Patent Document 3 uses a coaxial optical system and can favorably correct various aberrations generated by shortening the focal length and enlarging the angle of view. By using a cemented lens, it is excellent in manufacturability and achromaticity. In addition, by causing the light beam from the image display element to enter the lens while maintaining telecentricity, color shift of the image display element can be prevented, and excellent image quality can be provided. However, this eyepiece optical system becomes heavy due to the use of glass, and although it is thought that there is no health hazard when used in a short time such as a viewfinder, it is not used for a long time such as a head mounted display. It may be unsuitable for the intended use.

  An object of the present disclosure is to provide an eyepiece and a display device capable of enlarging an image with a wide angle of view and obtaining performance that can be suitably used for a head mounted display, for example.

  An eyepiece according to the present disclosure includes, in order from the eye point side, a first lens having a positive refractive power, a second lens having a positive refractive power with a convex surface facing the eye point side, and a convex surface facing the eye point side. A third lens having a positive refractive power, a fourth lens having a negative refractive power with a concave surface facing the image side, and a fifth lens having a convex surface facing the eye point side. .

  A display device according to the present disclosure includes an image display element and an eyepiece that enlarges an image displayed on the image display element, and the eyepiece is configured by the eyepiece according to the present disclosure.

  In the eyepiece or display device according to the present disclosure, the first to fifth lenses are arranged in order from the eye point side, and the configuration of each lens is optimized, so that an image can be enlarged with a wide angle of view. For example, performance that can be suitably used for a head mounted display can be obtained.

  According to the eyepiece or display device of the present disclosure, the first to fifth lenses are arranged in order from the eyepoint side, and the configuration of each lens is optimized, so that the image can be enlarged with a wide angle of view. For example, it is possible to obtain performance that can be suitably used for a head-mounted display.

1 is a lens cross-sectional view illustrating a first configuration example of an eyepiece lens according to an embodiment of the present disclosure and corresponding to Numerical Example 1. FIG. FIG. 4 is an aberration diagram showing various aberrations of the eyepiece lens corresponding to Numerical Example 1. 2 is a lens cross-sectional view illustrating a second configuration example of the eyepiece lens and corresponding to Numerical Example 2. FIG. FIG. 6 is an aberration diagram showing various types of aberration of the eyepiece lens corresponding to Numerical Example 2. 3 is a lens cross-sectional view illustrating a third configuration example of the eyepiece lens and corresponding to Numerical Example 3. FIG. It is an aberration diagram showing various aberrations of the eyepiece lens corresponding to Numerical Example 3. 9 is a lens cross-sectional view illustrating a fourth configuration example of the eyepiece lens and corresponding to Numerical Example 4. FIG. FIG. 10 is an aberration diagram showing various types of aberration of the eyepiece lens corresponding to Numerical Example 4. 10 is a lens cross-sectional view illustrating a fifth configuration example of the eyepiece lens and corresponding to Numerical Example 5. FIG. FIG. 10 is an aberration diagram showing various types of aberration of the eyepiece lens corresponding to Numerical Example 5. 6 is a lens cross-sectional view illustrating a sixth configuration example of the eyepiece lens and corresponding to Numerical Example 6. FIG. It is an aberration diagram showing various aberrations of the eyepiece lens corresponding to Numerical Example 6. 7 is a lens cross-sectional view illustrating a seventh configuration example of the eyepiece lens and corresponding to Numerical Example 7. FIG. It is an aberration diagram showing various aberrations of the eyepiece lens corresponding to Numerical Example 7. 8 illustrates an eighth configuration example of the eyepiece lens, and is a lens cross-sectional view corresponding to Numerical Example 8. FIG. FIG. 10 is an aberration diagram showing various types of aberration of the eyepiece lens corresponding to Numerical Example 8. 9 shows a ninth configuration example of the eyepiece lens, and is a lens cross-sectional view corresponding to Numerical Example 9. FIG. 10 is an aberration diagram showing various types of aberration of the eyepiece lens corresponding to Numerical Example 9. FIG. 10 is a lens cross-sectional view illustrating a tenth configuration example of the eyepiece lens and corresponding to Numerical Example 10. FIG. FIG. 11 is an aberration diagram showing various types of aberration of the eyepiece lens corresponding to Numerical example 10. 11 shows an eleventh configuration example of the eyepiece lens and is a lens cross-sectional view corresponding to Numerical Example 11. FIG. FIG. 12 is an aberration diagram showing various types of aberration of the eyepiece lens corresponding to Numerical Example 11. 12 is a lens cross-sectional view illustrating a twelfth configuration example of the eyepiece lens and corresponding to Numerical Example 12. FIG. It is an aberration diagram showing various aberrations of the eyepiece lens corresponding to Numerical Example 12. It is the external appearance perspective view which looked at the head mounted display as an example of a display apparatus from diagonally forward. It is the external appearance perspective view which looked at the head mounted display as an example of a display apparatus from diagonally backward.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be given in the following order.
1. 1. Basic configuration of lens Action and effect 3. Application example to display device 4. Numerical example of lens Other embodiments

[1. Basic lens configuration]
FIG. 1 illustrates a first configuration example of an eyepiece according to an embodiment of the present disclosure. This configuration example corresponds to the lens configuration of Numerical Example 1 described later. The basic configuration of the eyepiece according to the present embodiment will be described with reference to FIG. 1 as appropriate.

  The eyepiece according to the present embodiment has an eye point E.D. along the optical axis Z1. P. In order from the side, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are substantially constituted by five lenses.

  This eyepiece is applicable to an eyepiece optical system in a display device such as a head mounted display 200 (FIGS. 25 and 26) described later. When applied to a display device such as a head mounted display 200, as shown in FIG. 1, it is used to enlarge and display an image displayed on an image display element 100 such as an LCD (Liquid Crystal Display) or an organic EL display. . A seal glass SG for protecting the image display element 100 may be disposed on the front surface of the image display element 100.

  Eyepoint E.E. P. Corresponds to the pupil position of the observer and also functions as an aperture stop STO. The first lens L1 has a positive refractive power. The second lens L2 has a positive refractive power, and the eye point E.E. P. The convex surface is directed to the side. The third lens L3 has a positive refractive power, and the eye point E.E. P. The convex surface is directed to the side. The fourth lens L4 has negative refractive power and has a concave surface facing the image side (image display element 100 side). The fifth lens L5 has a positive refractive power, and the eye point E.E. P. The convex surface is directed to the side. Each lens is preferably aspheric.

  In addition, the eyepiece according to the present embodiment preferably satisfies a predetermined conditional expression described later.

[2. Action / Effect]
Next, functions and effects of the eyepiece according to the present embodiment will be described.

  In the eyepiece according to the present embodiment, the eye point E.E. P. In order from the side, the configuration is positive, positive, positive, negative, and positive, and is preceded by positive refractive power. The fifth lens L5 close to the image display element 100 will be described. P. Since the convex surface is directed to the side, the light beam emitted from the image display element 100 can be taken into the eyepiece optical system while maintaining telecentricity. Accordingly, the telecentricity is not maintained, that is, the color shift due to the color filter of the image display element 100 due to the incidence of the oblique light beam can be prevented, and a good image / video without color shift can be enlarged. To contribute.

  Since the fourth lens L4 has negative refractive power, the subsequent third lens L3, second lens L2, and first lens L1 have positive refractive power. Thus, it is excellent in enlarging the image from the image display element 100 while performing good chromatic aberration correction, providing an important wide angle of view in the head mounted display, and obtaining a high immersive feeling.

(Explanation of conditional expressions)
In the eyepiece according to the present embodiment, by optimizing the configuration of each lens so as to satisfy at least one of the following conditional expressions, preferably a combination of two or more conditional expressions, better performance Can be obtained.

It is desirable that the eyepiece according to the present embodiment satisfies the following conditional expression (1).
h × ω / E> 4 (1)
However,
h: Height of horizontal edge of image ω: Eye point P. Horizontal half angle of view E: Eye point P. To the first lens L1 (eye relief) (see FIG. 1)
And
When applied to a display device such as a head-mounted display 200 (FIGS. 25 and 26) described later, h is the height of the horizontal edge of the image displayed on the image display element 100.

  Conditional expression (1) is a conditional expression representing the relationship between the horizontal half angle of view ω and the eye relief E with respect to the height h of the horizontal edge of the image under the above-described configuration. Basically, the larger the image (image display element 100) to be enlarged, the easier it is to secure a wider angle of view. P. If the distance of the first lens L1 from the lens is reduced, it is easy to ensure a wide angle of view. That is, if it falls below the range of conditional expression (1), it becomes impossible to provide a wide angle of view while maintaining good image quality, leading to the loss of the attractiveness of the head mounted display.

In order to provide a wide angle of view while maintaining better image quality, it is preferable to set the numerical range of the conditional expression (1) as the following conditional expression (1) ′.
h × ω / E> 5 (1) ′

It is desirable that the eyepiece according to the present embodiment satisfies the following conditional expression (2).
5 <| (f1 + f2 + f3) / f4 | <18 (2)
However,
f1: focal length of the first lens L1 f2: focal length of the second lens L2 f3: focal length of the third lens L3 f4: focal length of the fourth lens L4.

  Conditional expression (2) is a conditional expression representing the relationship between the fourth lens L4 having negative refractive power and the third lens L3, second lens L2, and first lens L1 having positive refractive power. . If the conditional expression (2) exceeds the upper limit value, the negative refractive power of the fourth lens L4 with respect to the positive refractive power from the third lens L3 to the first lens L1 becomes too strong, and good chromatic aberration correction can be performed. A wide angle of view cannot be secured. On the other hand, if the conditional expression (2) exceeds the lower limit value, the negative refractive power of the fourth lens L4 becomes too weak, and a wide angle of view can be secured, but it becomes difficult to correct chromatic aberration. Further, since the focal length of the entire system becomes too strong and the Petzval sum tends to be large, field curvature also occurs greatly, making correction difficult, and it becomes impossible to provide good image quality. Furthermore, the fact that the focal length of the entire system is shortened makes it difficult to secure sufficient eye relief.

In order to obtain better optical performance, it is preferable to set the numerical range of the conditional expression (2) as the following conditional expression (2) ′.
7 <| (f1 + f2 + f3) / f4 | <16 (2) ′

It is desirable that the eyepiece according to the present embodiment satisfies the following conditional expression (3).
(Νd1 + νd2 + νd3) / 3−νd4> 22 (3)
However,
νd1: Abbe number of the first lens L1 νd2: Abbe number of the second lens L2 νd3: Abbe number of the third lens L3 νd4: Abbe number of the fourth lens L4.

  Conditional expression (3) is a conditional expression that defines the Abbe number of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 on the d-line. By using a glass material whose Abbe number is in the range of the conditional expression (3) for the first lens L1 to the fourth lens L4, it is possible to perform good chromatic aberration correction without increasing the power of the lens so much. Since the lens power is not strong, the occurrence of coma aberration and field curvature in the peripheral portion can be suppressed. Further, since the lens power is not strong, the production sensitivity, that is, the amount of aberration generated when a shift from the design value occurs can be suppressed, and excellent manufacturability can be provided.

In order to obtain better optical performance, it is preferable to set the numerical range of the conditional expression (3) as the following conditional expression (3) ′.
(Νd1 + νd2 + νd3) / 3−νd4> 25 (3) ′

It is desirable that the eyepiece according to the present embodiment satisfies the following conditional expression (4).
0.8 <| f5 / f4 | <2.0 (4)
However,
f5: The focal length of the fifth lens L5.

  Conditional expression (4) is a conditional expression representing the relationship of the fourth lens L4 with respect to the fifth lens L5. When the upper limit of this conditional expression is exceeded, the refractive power of the fourth lens L4 having negative refractive power becomes too strong and the refractive power of the fifth lens L5 becomes weak, so that the image display element 100 changes to the fifth lens L5. It becomes difficult to maintain telecentricity with respect to incident light rays. In addition, since the fifth lens L5 plays a major role in correcting distortion, the weak refractive power of the fifth lens L5 also hinders correction of distortion and provides good image quality. It becomes difficult. On the other hand, if the conditional expression (4) exceeds the lower limit, the refractive power of the fourth lens L4 becomes too weak, so that it becomes difficult to correct chromatic aberration, and it becomes difficult to provide good image quality.

In order to obtain better optical performance, it is preferable to set the numerical range of the conditional expression (4) as the following conditional expression (4) ′.
0.9 <| f5 / f4 | <1.7 (4) ′

It is desirable that the eyepiece according to the present embodiment satisfies the following conditional expression (5).
−50 <(R8 / R9) / f4 <50 (5)
However,
R8: Eye point E of the fourth lens L4 P. Side paraxial radius of curvature R9: The paraxial radius of curvature of the image side surface of the fourth lens L4.

  Conditional expression (5) is a conditional expression that defines the relationship of the refractive power of the fourth lens L4 with respect to the radius of curvature of each lens surface of the fourth lens L4. If conditional expression (5) does not fall within this range, it will be difficult to correct spherical aberration.

In order to obtain better optical performance, it is preferable to set the numerical range of the conditional expression (5) as the following conditional expression (5) ′.
−40 <(R8 / R9) / f4 <40 (5) ′

Further, it is desirable that all of the first lens L1 to the fifth lens L5 are made of a material having a linear expansion coefficient of 50 × 10 ⁻⁶ / ° C. or more. As a result, a lightweight resin lens can be used as a lens material, the image from the image display element 100 is greatly enlarged, and a wide angle of view is secured, and it is very light and worn in front of the eye for a long time. This makes the eyepiece optical system less fatigued.

  As described above, according to the present embodiment, the eye point E.E. P. Since the first lens L1 to the fifth lens L5 are arranged in order from the side and the configuration of each lens is optimized, the image can be enlarged with a wide angle of view, and can be suitably used for a head mounted display, for example. Performance can be obtained.

[3. Example of application to display device]
25 and 26 show a configuration example of a head mounted display 200 as an example of a display device to which the eyepiece according to the present embodiment is applied. The head mounted display 200 includes a main body unit 201, a forehead support unit 202, a nose pad unit 203, a headband 204, and a headphone 205. The forehead support 202 is provided at the upper center of the main body 201. The nose pad 203 is provided at the center lower part of the main body 201.

  When the user wears the head mounted display 200 on the head, the forehead support unit 202 contacts the user's forehead and the nose pad unit 203 contacts the nose. Further, the headband 204 abuts behind the head. Thereby, in this head mounted display 200, the load of an apparatus can be disperse | distributed to the whole head, and a user's burden can be eased and it can mount | wear.

  The headphones 205 are provided for the left ear and for the right ear, and can provide sound independently to the left ear and the right ear.

  The main body 201 incorporates a circuit board and an optical system for displaying an image. The main body unit 201 is provided with a left eye display unit 210L and a right eye display unit 210R, and can provide images independently for the left eye and the right eye. The left eye display unit 210L is provided with an image display element 100 for the left eye and an eyepiece lens for the left eye that enlarges an image displayed on the image display element 100 for the left eye. The right eye display unit 210R is provided with an image display element 100 for the right eye and an eyepiece lens for the right eye that enlarges an image displayed on the image display element 100 for the right eye. The eyepiece according to this embodiment can be applied as the left eyepiece and right eyepiece.

  Note that image data is supplied to the image display element 100 from an image reproduction device (not shown). It is also possible to perform 3D display by supplying 3D image data from the image playback device and displaying images with parallax between the left eye display unit 210L and the right eye display unit 210R.

  Although an example in which the display device is applied to the head mounted display 200 has been described here, the application range of the display device is not limited to the head mounted display 200, and for example, the display device may be applied to an electronic viewfinder of a camera. good.

  Further, the eyepiece according to the present embodiment can be applied not only to an application for enlarging an image displayed on the image display element 100 but also to an observation apparatus for enlarging an optical image formed by an objective lens. .

<4. Numerical Examples of Lens>
Next, specific numerical examples of the eyepiece according to the present embodiment will be described.
In addition, the meanings of symbols shown in the following tables and descriptions are as shown below. “Si” is an eye point E.I. P. Is the number of the i-th surface that is numbered sequentially so as to increase toward the image side. “Ri” indicates the radius of curvature (mm) of the i-th surface. “Di” indicates a distance (mm) on the optical axis between the i-th surface and the (i + 1) -th surface. “Ndi” indicates the value of the refractive index at the d-line (wavelength: 587.6 nm) of the material (medium) of the optical element having the i-th surface. “Νdi” indicates the value of the Abbe number in the d-line of the material of the optical element having the i-th surface. H ′ is the height of the diagonal end of the image (the image displayed on the image display element 100), E is the eye relief, and ω is the eye point E.E. P. The horizontal half angle of view is shown. A surface having a radius of curvature of “∞” indicates that it is a flat surface or a diaphragm surface.

  All of the eyepiece lenses according to the following numerical examples have the basic configuration of the lens described above and a configuration that satisfies desirable conditions. In addition, each lens surface of the first lens L1 to the fifth lens L5 is aspheric.

The aspherical shape is expressed by the following equation. In the aspheric coefficient data, the symbol “E” indicates that the next numerical value is a “power exponent” with a base of 10, and the numerical value represented by an exponential function with the base 10 is “E”. Indicates that the number before “is multiplied. For example, “1.0E-05” indicates “1.0 × 10 ⁻⁵ ”.

(Aspherical formula)
Z = (Y ² / R) / [1+ {1− (1 + K) (Y ² / R ² )} ^1/2 ] + ΣAi · Y ⁱ
However,
Z: Depth of aspheric surface Y: Height from optical axis R: Paraxial radius of curvature K: Conic constant Ai: An aspherical coefficient of i-th order (i is an integer of 3 or more).

[Numerical Example 1]
[Table 1] and [Table 2] show specific lens data corresponding to the eyepiece 1 according to the first configuration example shown in FIG. In particular, [Table 1] shows the basic lens data, and [Table 2] shows data related to the aspherical surface.

[Numerical Example 2]
[Table 3] and [Table 4] show specific lens data corresponding to the eyepiece 2 according to the second configuration example shown in FIG. In particular, [Table 3] shows the basic lens data, and [Table 4] shows data related to the aspherical surface.

[Numerical Example 3]
[Table 5] and [Table 6] show specific lens data corresponding to the eyepiece 3 according to the third configuration example shown in FIG. In particular, [Table 5] shows the basic lens data, and [Table 6] shows data related to the aspherical surface.

[Numerical Example 4]
[Table 7] and [Table 8] show specific lens data corresponding to the eyepiece 4 according to the fourth configuration example shown in FIG. In particular, [Table 7] shows the basic lens data, and [Table 8] shows data related to the aspherical surface.

[Numerical Example 5]
[Table 9] and [Table 10] show specific lens data corresponding to the eyepiece 5 according to the fifth configuration example shown in FIG. In particular, [Table 9] shows the basic lens data, and [Table 10] shows data related to the aspherical surface.

[Numerical Example 6]
[Table 11] and [Table 12] show specific lens data corresponding to the eyepiece 6 according to the sixth configuration example shown in FIG. In particular, [Table 11] shows the basic lens data, and [Table 12] shows data related to the aspherical surface.

[Numerical Example 7]
[Table 13] and [Table 14] show specific lens data corresponding to the eyepiece lens 7 according to the seventh configuration example shown in FIG. In particular, [Table 13] shows the basic lens data, and [Table 14] shows data related to the aspherical surface.

[Numerical Example 8]
[Table 15] and [Table 16] show specific lens data corresponding to the eyepiece 8 according to the eighth configuration example shown in FIG. In particular, [Table 15] shows basic lens data, and [Table 16] shows data related to aspheric surfaces.

[Numerical Example 9]
[Table 17] and [Table 18] show specific lens data corresponding to the eyepiece 9 according to the ninth configuration example shown in FIG. In particular, [Table 17] shows the basic lens data, and [Table 18] shows data related to the aspherical surface.

[Numerical Example 10]
[Table 19] and [Table 20] show specific lens data corresponding to the eyepiece 10 according to the tenth configuration example shown in FIG. In particular, [Table 19] shows the basic lens data, and [Table 20] shows data related to the aspherical surface.

[Numerical Example 11]
[Table 21] and [Table 22] show specific lens data corresponding to the eyepiece 11 according to the eleventh configuration example shown in FIG. In particular, [Table 21] shows basic lens data, and [Table 22] shows data related to aspheric surfaces.

[Numerical Example 12]
[Table 23] and [Table 24] show specific lens data corresponding to the eyepiece 12 according to the twelfth configuration example shown in FIG. In particular, [Table 23] shows the basic lens data, and [Table 24] shows data related to the aspherical surface.

[Other numerical data of each example]
[Table 25] and [Table 26] show values relating to the above-described conditional expressions for the numerical examples. As can be seen from [Table 25], for each conditional expression, the value of each numerical example falls within the numerical range.

[Aberration performance]
The aberration performance of each numerical example is shown in FIGS. 2, 4, 6, 8, 8, 10, 12, 14, 16, 18, 20, 22, and 24. FIG. Each aberration is represented by eye point E.E. P. The ray traced from the side.

  In these drawings, spherical aberration, astigmatism, and distortion (distortion aberration) are shown as aberration diagrams. In each aberration diagram, the aberration at 538 nm is indicated by a solid line, the aberration at 458 nm is indicated by a one-dot chain line, and the aberration at 629 nm is indicated by a broken line. In the graph showing astigmatism, X1, X2, and X3 indicate aberrations in the sagittal direction, and Y1, Y2, and Y3 indicate aberrations in the meridional direction.

  As can be seen from each of the above aberration diagrams, an eyepiece lens in which aberrations are satisfactorily corrected can be realized for each example.

<5. Other Embodiments>
The technology according to the present disclosure is not limited to the description of the above-described embodiments and examples, and various modifications can be made.
For example, the shapes and numerical values of the respective parts shown in the numerical examples are merely examples of embodiments for carrying out the present technology, and the technical scope of the present technology is interpreted in a limited manner by these. There should be no such thing.

  In the above-described embodiments and examples, the configuration including five lenses has been described. However, a configuration further including a lens having substantially no refractive power may be used.

For example, this technique can take the following composition.
[1]
From the eyepoint side,
A first lens having a positive refractive power;
A second lens having positive refractive power with a convex surface facing the eye point side;
A third lens having a positive refractive power with a convex surface facing the eye point,
A fourth lens having negative refractive power with the concave surface facing the image side;
An eyepiece comprising a fifth lens having a convex surface facing the eye point.
[2]
The eyepiece according to [1], which satisfies the following conditional expression.
h × ω / E> 4 (1)
However,
h: Height of the horizontal edge of the image ω: Horizontal half angle of view on the eye point side E: Distance from the eye point to the first lens (eye relief)
And
[3]
The eyepiece according to [1] or [2], which satisfies the following conditional expression.
5 <| (f1 + f2 + f3) / f4 | <18 (2)
However,
f1: focal length of the first lens f2: focal length of the second lens f3: focal length of the third lens f4: focal length of the fourth lens
[4]
The eyepiece lens according to any one of [1] to [3], wherein the following conditional expression is satisfied.
(Νd1 + νd2 + νd3) / 3−νd4> 22 (3)
However,
νd1: Abbe number of the first lens νd2: Abbe number of the second lens νd3: Abbe number of the third lens νd4: Abbe number of the fourth lens
[5]
The eyepiece lens according to any one of [1] to [4], wherein the following conditional expression is satisfied.
0.8 <| f5 / f4 | <2.0 (4)
However,
f5: The focal length of the fifth lens.
[6]
The eyepiece lens according to any one of [1] to [5], wherein the following conditional expression is satisfied.
−50 <(R8 / R9) / f4 <50 (5)
However,
R8: Paraxial radius of curvature of eye point side surface of the fourth lens R9: Paraxial radius of curvature of the image side surface of the fourth lens.
[7]
The eyepiece lens according to any one of [1] to [6], wherein all of the first to fifth lenses are made of a material having a linear expansion coefficient of 50 × 10 ⁻⁶ / ° C. or more.
[8]
The eyepiece lens according to any one of [1] to [7], further including a lens having substantially no refractive power.
[9]
An image display element, and an eyepiece for enlarging an image displayed on the image display element,
The eyepiece is
From the eyepoint side,
A first lens having a positive refractive power;
A second lens having a positive refractive power with the convex surface facing the eye point side;
A third lens having a positive refractive power with a convex surface facing the eye point side;
A fourth lens having negative refractive power with the concave surface facing the image side;
And a fifth lens having a convex surface facing the eye point side.
[10]
The display device according to [9], wherein the eyepiece further includes a lens having substantially no refractive power.

  L1 ... 1st lens, L2 ... 2nd lens, L3 ... 3rd lens, L4 ... 4th lens, SG ... Seal glass, E ... Eye relief, E. P. ... eye point, h ... height at the horizontal end of the image, h '... height at the diagonal end of the image, Z1 ... optical axis, 1-12 ... eyepiece, 100 ... image display element, 200 ... head mounted display, DESCRIPTION OF SYMBOLS 201 ... Main body part, 202 ... Forehead pad part, 203 ... Nose pad part, 204 ... Headband, 205 ... Headphone, 210L ... Left eye display part, 210R ... Right eye display part.

Claims (8)

From the eyepoint side,
A first lens having a positive refractive power;
A second lens having positive refractive power with a convex surface facing the eye point side;
A third lens having a positive refractive power with a convex surface facing the eye point,
A fourth lens having negative refractive power with the concave surface facing the image side;
An eyepiece comprising a fifth lens having a convex surface facing the eye point. The eyepiece according to claim 1, wherein the following conditional expression is satisfied.
h × ω / E> 4 (1)
However,
h: Height of the horizontal edge of the image ω: Horizontal half angle of view on the eye point side E: Distance from the eye point to the first lens (eye relief)
And The eyepiece according to claim 1, wherein the following conditional expression is satisfied.
5 <| (f1 + f2 + f3) / f4 | <18 (2)
However,
f1: focal length of the first lens f2: focal length of the second lens f3: focal length of the third lens f4: focal length of the fourth lens The eyepiece according to claim 1, wherein the following conditional expression is satisfied.
(Νd1 + νd2 + νd3) / 3−νd4> 22 (3)
However,
νd1: Abbe number of the first lens νd2: Abbe number of the second lens νd3: Abbe number of the third lens νd4: Abbe number of the fourth lens The eyepiece according to claim 1, wherein the following conditional expression is satisfied.
0.8 <| f5 / f4 | <2.0 (4)
However,
f5: The focal length of the fifth lens. The eyepiece according to claim 1, wherein the following conditional expression is satisfied.
−50 <(R8 / R9) / f4 <50 (5)
However,
R8: Paraxial radius of curvature of eye point side surface of the fourth lens R9: Paraxial radius of curvature of the image side surface of the fourth lens. The eyepiece according to claim 1, wherein all of the first to fifth lenses are made of a material having a linear expansion coefficient of 50 × 10 ⁻⁶ / ° C. or more. An image display element, and an eyepiece for enlarging an image displayed on the image display element,
The eyepiece is
From the eyepoint side,
A first lens having a positive refractive power;
A second lens having a positive refractive power with the convex surface facing the eye point side;
A third lens having a positive refractive power with a convex surface facing the eye point side;
A fourth lens having negative refractive power with the concave surface facing the image side;
And a fifth lens having a convex surface facing the eye point side.

Images