Light source device and image display device

Abstract

The light source device includes a light source and an optical system including a lens located in an optical path of light from the light source. The lens has a numerical aperture of 0.16 or less, and the light source has a sum of radiation angles defined as a sum of a first radiation angle measured with respect to a first direction and a second radiation angle measured with respect to a second direction orthogonal to the first direction.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of Japanese Patent Application No. JP 2022-111310 filed on Jul. 11, 2022, the entire contents of which are hereby incorporated by reference into this application. Technical Field

[0003] A technology according to the present disclosure (hereinafter also referred to as “the present technology”) relates to a light source device and an image display device. Background Art

[0004] In the related art, there is known a light source device that emits light from a light source via an optical system including a lens.

[0005] There is a prior art light source device in which the numerical aperture (NA) of a lens is increased in order to compensate for the insufficient light amount of the light source (for example, see PTL 1). As described above, increasing the numerical aperture (NA) of a lens as a method of improving efficiency has been widely recognized as a common optical design.

[0006] Meanwhile, there is a related art light source device including an optical filter that adjusts (reduces) the amount of light from a light source (for example, see PTL 2).

[0007] Prior art literature

[0008] Patent Literature

[0009] PTL 1: JP 2017-3922A

[0010] PTL 2: JP H05-120724A Summary of the invention

[0011] Technical issues

[0012] For example, PTL 1 does not mention any technology for dealing with the excessive amount of light of the light source. For example, in PTL 2, an additional component such as an optical filter is used to cope with the excessive amount of light of the light source.

[0013] Therefore, a main object of the present technology is to provide a light source device capable of coping with an excessive amount of light of a light source without using an additional component such as an optical filter.

[0014] Solutions to the problem

[0015] The present technology provides a light source device, which includes:

[0016] at least one light source; and

[0017] an optical system disposed on an optical path of light from the light source and comprising a lens,

[0018] The lens has a numerical aperture of 0.16 or less, and the sum of radiation angles of the light source is 14° or more, the sum of radiation angles being the sum of radiation angles respectively associated with two directions orthogonal to each other.

[0019] The numerical aperture may be 0.09 or less, and the sum of the radiation angles may be 14° or more.

[0020] The numerical aperture may be 0.16 or less, and the sum of the radiation angles may be 23° or more.

[0021] The numerical aperture may be 0.09 or less, and the sum of the radiation angles may be 23° or more.

[0022] The lens may be a spherical lens or an aspherical lens.

[0023] The light source may be a semiconductor laser.

[0024] The present technology provides an image display device, comprising:

[0025] The light source device;

[0026] an image forming unit that forms an image using light from the light source device; and

[0027] A projection optical system projects light that forms the image.

[0028] The image forming unit may include an optical deflector.

[0029] The image forming unit may include a digital micromirror device.

[0030] The image forming unit may include a liquid crystal element.

[0031] The at least one light source may be a plurality of light sources having different light emission wavelengths, a plurality of lenses may be arranged to correspond to the plurality of light sources, and the optical system of the light source device may combine light beams respectively emitted from the plurality of light sources and passing through corresponding lenses.

[0032] The at least one light source may be a plurality of light sources having different emission wavelengths, a plurality of lenses may be arranged to correspond to the plurality of light sources, a plurality of liquid crystal elements may be arranged to correspond to the plurality of lenses, and the image forming unit may make the light beams passing through the plurality of lenses respectively incident on the liquid crystal elements corresponding to the lenses, and combine the light beams passing through the liquid crystal elements.

[0033] An optical element that guides the light passing through the projection optical system to an eyeball of a user may be further provided.

[0034] The image forming device may further include a light-condensing optical element provided on the optical path of the light between the light source device and the image forming unit.

[0035] The image forming unit may include a digital micromirror device, and the light-condensing optical element may condense light on the optical path of the light between the light source device and the digital micromirror device.

[0036] The image forming unit may include an optical deflector, and the light focusing optical element may focus light on the optical deflector.

[0037] The projection optical system may include a focusing optical element.

[0038] The projection optical system may include a projection optical element, and the light focusing optical element may be disposed between the image forming unit and the projection optical element.

[0039] An optical element may be further provided to guide the light passing through the projection optical system to the user's eyeball. The projection optical system may include a projection optical element, and the focusing optical element may be arranged on the optical path of the light between the projection optical element and the optical element.

[0040] At least the optical element may be mounted on the user's head. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 2 is a diagram describing an image display device according to Comparative Example 1.

[0042] Figure 2 2 is a diagram describing an image display device according to Comparative Example 2.

[0043] Figure 3 It is a view describing the definition of the radiation angle of a laser.

[0044] Figure 4 is a view describing a method for measuring the radiation angle of a laser (Part 1).

[0045] Figure 5 is a view describing a method for measuring the radiation angle of a laser (Part 2).

[0046] Figure 6 is a diagram that describes the numerical aperture of a lens.

[0047] Figure 7This is a view describing a method for measuring the numerical aperture of a lens (Part 1).

[0048] Figure 8 This is a view describing a method for measuring the numerical aperture of a lens (Part 2).

[0049] Fig. 9 2 is a diagram describing an image display device according to Comparative Example 3.

[0050] Fig.10 is a view describing how to achieve efficiency (Part 1).

[0051] Fig.11 is a view that describes how to achieve efficiency (Part 2).

[0052] Fig.12 is a diagram that describes how to obtain the efficiency of a lens with a small numerical aperture.

[0053] Fig.13 is a view describing a method for reducing the numerical aperture of a lens.

[0054] Fig.14 A is a view showing a light source device according to Comparative Example 4. Fig.14 B is a view showing a configuration example 1 of a light source device according to the present technology.

[0055] Fig.15 A is a view showing an image display device according to Comparative Example 5. Fig.15 B is a view showing an image display device according to Comparative Example 6. Fig.15 C is a view showing a configuration example 1 of the image display device according to the present technology.

[0056] Fig.16 A is a view showing an image display device according to Comparative Example 7. Fig.16 B is a view showing an image display device according to Comparative Example 8. Fig.16 C is a view showing configuration example 2 of the image display device according to the present technology.

[0057] Fig.17 is a view showing an image display device according to Comparative Example 9.

[0058] Fig.18 A and Fig.18 B is a view describing the principle of resolution enhancement.

[0059] Fig.19 is a diagram showing the relationship between the sum of radiation angles, numerical aperture, and efficiency (Part 1).

[0060] Fig. 20A is a diagram showing the relationship among the numerical aperture, the peripheral light quantity ratio, and the projection light quantity. Fig. 20 B is a diagram showing the relationship between the numerical aperture and the volume ratio.

[0061] Fig.21 A is a diagram showing the relationship among the numerical aperture, adjustment sensitivity, and projection light amount. Fig.21 B is a diagram showing the relationship between the numerical aperture and the change in the amount of light due to adjustment and the amount of projection light.

[0062] Fig. 22 is a diagram showing the relationship between the sum of radiation angles, numerical aperture, and efficiency (Part 2).

[0063] Fig.23 is a diagram showing the relationship between numerical aperture and light intensity distribution.

[0064] Fig.24 is a diagram showing the relationship between the sum of radiation angles, numerical aperture, and efficiency (Part 3).

[0065] Fig.25 1 is a diagram showing a positional relationship between a light source and a lens in each of a light source device of the related art and a light source device of the present art.

[0066] Fig.26 1 is a diagram for describing the adjustment sensitivity of a light source device of the related art (when the position deviation and the angle deviation are small).

[0067] Fig. 27 It is a diagram describing the adjustment sensitivity of the light source device of the present technology (when the position deviation and the angle deviation are small).

[0068] Fig.28 1 is a diagram for describing the adjustment sensitivity of a light source device of the related art (when position deviation and angle deviation are large).

[0069] Fig.29 It is a diagram for describing the adjustment sensitivity of the light source device of the present technology (when the position deviation and the angle deviation are large).

[0070] Fig.30 : is a diagram showing a configuration example 3 of the image display device according to the present technology.

[0071] Fig.31 : is a block diagram showing the functions of configuration example 3 of the image display device according to the present technology.

[0072] Fig.32 : is a view showing a configuration example 4 of the image display device according to the present technology.

[0073] Fig.33 is a view showing a configuration example 5 of the image display device according to the present technology.

[0074] Fig.34 This is a diagram comparing the volumes of a light source device of the prior art and a light source device of the present technology.

[0075] Fig.35 : is a view showing an image display device according to a first embodiment of the present technology.

[0076] Fig.36 It is a view showing an image display device according to a second embodiment of the present technology.

[0077] Fig.37 It is a view showing an image display device according to a third embodiment of the present technology.

[0078] Fig.38 It is a view showing an image display device according to a fourth embodiment of the present technology.

[0079] Fig.39 It is a view showing an image display device according to a fifth embodiment of the present technology.

[0080] Fig.40 It is a view showing an image display device according to a sixth embodiment of the present technology.

[0081] Fig.41 It is a view showing an image display device according to a seventh embodiment of the present technology.

[0082] Fig.42 It is a view showing an image display device according to an eighth embodiment of the present technology.

[0083] Fig.43 : is a view showing an image display device according to a ninth embodiment of the present technology. DETAILED DESCRIPTION

[0084] Hereinafter, preferred embodiments of the present technology will be described in detail with reference to the accompanying drawings. It should be noted that constituent elements having substantially the same functional configuration in the present specification and the accompanying drawings will be represented by the same figure marks, and their redundant descriptions will be omitted. The embodiments described below show representative embodiments of the present technology, and the scope of the present technology is not narrowly interpreted by these embodiments. In this description, even in the case where each of the light source device and the image display device according to the present technology is described as exhibiting multiple effects, each of the light source device and the image display device according to the present technology only needs to exhibit at least one effect. The effects described in this specification are merely examples and are not limited, and other effects may also exist.

[0085] Additionally, the description will be made in the following order.

[0086] 0. Introduction

[0087] 1. Basic concepts as the basis of this technology

[0088] 2. Configuration Example 1 of the Light Source Device According to the Present Technology

[0089] 3. Configuration Examples 1 and 2 of the Image Display Device According to the Present Technology

[0090] 4. Features of this technology 1

[0091] 5. Features of this technology 2

[0092] 6. Features of this technology 3

[0093] 7. Adjust sensitivity

[0094] 8. Configuration Examples 3 to 5 of the Image Display Device According to the Present Technology

[0095] 9. Volume of the light source device according to the present technology and the light source device of the prior art

[0096] 10. Image display device according to first to ninth embodiments of the present technology

[0097] 11. Modification examples of this technology

[0098] <0. Introduction>

[0099] For example, in the prior art, in an image display device (such as a projector) using a laser as a light source, in order to compensate for the insufficient light amount of the light source, a method of improving the efficiency of the optical system is adopted. Specifically, in order to improve the image forming efficiency, the NA of the lens used to form the image is increased.

[0100] For example, on the other hand, in an image display device for direct retinal projection, in order to ensure the safety of the retina, it is necessary to reduce the amount of light from the light source using an additional component such as an optical filter (e.g., a neutral density (ND) filter). Therefore, there is a problem of increased cost due to the additional component and a space required for installing the additional component.

[0101] Therefore, as a result of intensive studies, the inventors have developed a light source device according to the present technology as a light source device capable of coping with an excessive amount of light of a light source without using an additional component such as an optical filter.

[0102] Meanwhile, in the laser scanning projector, the laser light flux corresponding to one pixel is emitted in a substantially parallel state. The laser beam gradually converges to the beam waist, where the beam diameter becomes the smallest and gradually diverges after the beam waist. Figure 1 In order to increase the resolution of the optical system in the image display device of the comparative example 1 shown, it is necessary to increase the NA of the lens L1 to reduce the light beam. This means that a large light flux diameter proportional to the distance to the projection plane is required on the lens closest to the projection plane. In the comparative example 1, when trying to increase the NA of the lens L1, the size of the scanning mirror MM becomes a limitation, thereby limiting the light flux diameter. In order not to be limited, it is necessary to increase the size of the scanning mirror MM. However, in this case, the response characteristics deteriorate, the device size increases, and the cost increases.

[0103] exist Figure 2 In the image display device of the comparative example 2 shown, when the purpose is to improve the resolution, an intermediate image forming point is provided in the optical system to improve the resolution, but in addition to the lens L1, it is necessary to add lenses L2 and L3 that produce the intermediate image forming point, which leads to increased costs.

[0104] Therefore, the inventors further studied and developed an image display device including a light source device according to the present technology as an image display device capable of improving the resolution of an optical system while suppressing deterioration of response characteristics, increase in device size, and increase in cost.

[0105] <1. Basic concepts that underlie this technology>

[0106] like Figure 3 As shown, a laser light source (e.g., a laser diode (LD)) radiates laser light at a predetermined radiation angle (divergence angle). The radiation angle of the LD includes a radiation angle θ⊥ in the Y direction and a radiation angle θ / / in the X direction, where the Y direction is the stacking direction of the laser diode chip (LD chip) and the X direction is a direction perpendicular to the stacking direction. Each of the radiation angles can be defined as an angle of half the value obtained by normalizing the intensity distribution of the laser beam (peak intensity of the Gaussian distribution). In this specification, the sum of θ⊥ and θ / / is referred to as the "sum of radiation angles". From Figure 3 It can be understood that the sum of the radiation angles is the sum of the first radiation angle measured relative to a first direction (e.g., y direction) and the second radiation angle measured relative to a second direction orthogonal to the first direction (e.g., x direction). As an example, the laser diode chip has a double heterostructure, in which a first cladding layer, an active layer, and a second cladding layer are sequentially stacked along the Y direction. It should be noted that the laser diode is also called an "edge-emitting laser".

[0107] Can be Figure 4 The measurement device including a power meter shown measures the radiation angle. The measurement is performed by installing the power meter at a position separated by a predetermined distance from the position where the light source is installed. The power meter rotates around the light source to measure the light intensity. Figure 5As shown in Figure 1, the measured value of the power meter changes depending on the angular position of the power meter. Figure 3 The method shown calculates the radiation angle based on the measured values.

[0108] like Figure 6 As shown, the numerical aperture (NA) of the lens is expressed by the following formula (1), which uses the maximum angle θ of light incident on the lens relative to the optical axis and the refractive index n1 of the medium between the light source and the lens.

[0109]

[0110] Usually, the medium between the light source and the lens in the light source device is air, and n1 = 1.0. Figure 7 The interferometer shown measures NA. Figure 7 The interferometer in is a commonly used interferometer. In this interferometer, the light from the LD is transmitted through the first device lens, incident on the half-reflective mirror, and is branched into reflected light and transmitted light by the half-reflective mirror. The reflected light branched by the half-reflective mirror passes through the measuring lens (lens to be measured), is reflected by the reference sphere (concave mirror), passes through the measuring lens again, and is incident on the CCD via the half-reflective mirror and the second device lens. The transmitted light branched by the half-reflective mirror is reflected by RefFlat (plane mirror), reflected by the half-reflective mirror, and is incident on the CCD via the second device lens. At this time, as Figure 8 As shown, when the transmitted light and reflected light of the half mirror branch merge and interfere, the CCD captures the image of the generated interference fringes. Therefore, the captured interference fringes are measured to calculate the effective diameter R of the measuring lens. In addition, the distance between the reference spherical surface and the measuring lens can be measured by the interval meter, and the focal length F of the measuring lens can be calculated based on its measured value and the thickness of the measuring lens.

[0111] The NA of the measurement lens can be obtained from the following formulas (2) to (4) using the effective diameter R and the focal length F.

[0112] [Mathematical formula 1]

[0113]

[0114] [Mathematical formula 2]

[0115]

[0116] [Mathematical formula 3]

[0117]

[0118] like Fig. 9The image display device of the comparative example 3 shown is a projector, and includes a first laser diode emitting red light (laser with a red component); a second laser diode emitting green light (laser with a green component); a third laser diode emitting blue light (laser with a blue component); first to third lenses into which the laser beams from the first to third laser diodes are incident; and a combining unit including first to third mirrors and combining the laser beams respectively passing through the first to third lenses. Each of the first to third lenses is a collimating lens that converts the laser light from each of the first to third laser diodes from divergent light to substantially parallel light. The laser light (combined light) combined by the combining unit is incident on the MEMS mirror via a mirror for deflection and scanning, and an image is formed on a display device (e.g., a screen surface, a wall surface, etc.).

[0119] Regarding light emitted from each of the laser diodes, only light transmitted through the corresponding lens can form an image, and the efficiency v can be obtained according to the following formulas (5) to (7).

[0120] In the presence of a lens, the image forming efficiency v1 is expressed by the following formula (5) (see Fig.10 ).

[0121] [Formula 4]

[0122]

[0123] In the absence of a lens, the image forming efficiency v0 is expressed by the following formula (6) (see Fig.11 ).

[0124] [Formula 5]

[0125]

[0126] The efficiency v of light transmitted through the lens can be obtained according to the above formulas (5) and (6) and the following formula (7).

[0127] [Mathematical formula 6]

[0128]

[0129] The image forming efficiency v2 of a lens with a smaller NA is expressed by the following formula (8) (see Fig.12 ).

[0130] [Formula 7]

[0131]

[0132] In the case where the NA of the lens is small, the amount of light emitted from the light source absorbed by the lens decreases, thereby establishing the following formula (9).

[0133] [Mathematical formula 8]

[0134]

[0135] Alternatively, the focal length of the lens can be increased as a method of reducing the NA (see Fig.13 ). The image forming efficiency v3 of the lens in this case is expressed by the following formula (10), and formula (11) is established between v3 and v2.

[0136] [Mathematical formula 9]

[0137]

[0138] [Formula 10]

[0139]

[0140] <2. Configuration Example 1 of the Light Source Device According to the Present Technology>

[0141] Hereinafter, Configuration Example 1 of the light source device according to the present technology will be described in comparison with a comparative example.

[0142] (Configuration example 1 of light source device)

[0143] Fig.14 A is a view showing a light source device according to Comparative Example 4. Fig.14 B is a view showing a configuration example 1 of the light source device according to the present technology.

[0144] like Fig.14 As shown, in the light source device according to Comparative Example 4, a lens having a large NA (for example, NA>0.16) is arranged on the optical path of the light radiated from the LD. Therefore, the intensity distribution of the radiated light radiated from the LD and passing through the lens shows a steep Gaussian distribution. In this case, the peripheral light quantity ratio A / P (A: intensity at the lens opening position, P: peak intensity), which is the ratio of the intensity A at the lens opening position to the peak intensity P, increases, and the integrated light quantity, which is the integrated value of the light quantity of the light transmitted through the lens, also increases. That is, the light source device according to Comparative Example 4 is suitable for the insufficient light quantity of the light source (which helps to improve efficiency), and has a very simple configuration including only the LD and the lens. For example, the lens is a collimator lens (also called a collimator lens).

[0145] like Fig.14As shown in FIG. 1B, in configuration example 1 of a light source device according to the present technology, a lens (e.g., a spherical lens or an aspherical lens) having a small NA (e.g., NA ≤ 0.16) is disposed on the optical path of light radiated from the LD. Therefore, the intensity distribution of the radiated light radiated from the LD and passing through the lens shows a gentle Gaussian distribution, the peripheral light quantity ratio A / P (A: intensity at the lens opening position, P: peak intensity), which is the ratio of the intensity A at the lens opening position to the peak intensity P, decreases, and the integrated light quantity, which is the integrated value of the light quantity transmitted through the lens, also decreases. That is, configuration example 1 of the light source device is suitable for excessive light quantity of the light source (which contributes to reduced efficiency), and has a very simple configuration including only the LD and the lens. For example, the lens is a collimator lens (also called a collimator lens).

[0146] Note that, as the light source in Configuration Example 1 of the light source device, another semiconductor laser such as a vertical cavity surface emitting laser (VCSEL) may be used instead of the LD.

[0147] <3. Configuration Examples 1 and 2 of the Image Display Device According to the Present Technology>

[0148] Hereinafter, configuration examples 1 and 2 of the image display device according to the present technology will be described by comparison with a comparative example.

[0149] Fig.15 A is a view showing an image display device according to Comparative Example 5. Fig.15 B is a view showing an image display device according to Comparative Example 6. Fig.15 C is a view showing a configuration example 1 of the image display device according to the present technology.

[0150] Meanwhile, generally speaking, the light radiated from the light source in the image display device is converted into substantially parallel light or convergent light by a lens, converted into light for forming an image by an image forming unit, and then converged (imaged) into a predetermined spot size by a projection lens. The image forming unit may also be referred to as an image forming system. The spot diameter of the light converged by the projection lens is an element that determines the resolution in the image display device. Therefore, it is necessary to reduce the spot diameter.

[0151] like Fig.15 As shown in FIG. 1A , in the image display device according to Comparative Example 5, a lens having a large NA (for example, NA>0.16) is disposed on the optical path of light radiated from the LD, and an aperture (opening member) and a projection lens are disposed in order from the lens side on the optical path of light passing through the lens. An image forming unit (not shown) that forms an image using light is disposed on the optical path of light between the lens and the projection lens. That is, the image display device according to Comparative Example 5 has a configuration in which the image forming unit, the aperture, and the projection lens are added to the light source device according to Comparative Example 4 (see FIG. 1B ). Fig.14 A). In the image display device according to Comparative Example 5, the intensity distribution of the radiated light radiated from the LD and passing through the lens shows a steep Gaussian distribution, the integrated light amount which is the integrated value of the light amount of the radiated light increases, and the spot diameter of the main lobe of the light passing through the image forming unit, the aperture, and the projection lens also increases. Therefore, it is possible to achieve efficiency improvement in the image display device according to Comparative Example 5, but there is room for improvement in terms of resolution enhancement.

[0152] like Fig.15 As shown in FIG. 1B , in the image display device according to Comparative Example 6, a lens having a large NA (for example, NA>0.16) is disposed on the optical path of light radiated from the LD, an attenuation filter (ND filter) is disposed on the optical path of light passing through the lens, and an aperture (opening member) and a projection lens are disposed in sequence from the attenuation filter side on the optical path of light passing through the attenuation filter. An image forming unit (not shown) that forms an image using light is disposed on the optical path of light between the attenuation filter and the projection lens. That is, the image display device according to Comparative Example 6 has a configuration in which the attenuation filter, the image forming unit, the aperture, and the projection lens are added to the light source device according to Comparative Example 4 (see FIG. 4 ). Fig.14 A) configuration. In the image display device according to Comparative Example 6, the intensity distribution of the radiated light radiated from the LD and sequentially passing through the lens and the attenuation filter shows a gentle Gaussian distribution, the integrated light amount as the integrated value of the light amount of the radiated light is reduced, and the spot diameter of the main lobe of the light passing through the image forming unit, the aperture, and the projection lens is also reduced. That is, in the image display device according to Comparative Example 6, the spot diameter can be reduced by reducing the central light amount of the light intensity distribution and increasing the peripheral light amount using the attenuation filter. Therefore, reduced efficiency and improved resolution can be achieved in the image display device according to Comparative Example 6, but the attenuation filter is required as an additional component, which leads to increased cost.

[0153] like Fig.15 As shown in C, in Configuration Example 1 of an image display device according to the present technology, a lens (e.g., a spherical lens or an aspherical lens) having a small NA (e.g., NA ≤ 0.16) is disposed on the optical path of light radiated from an LD (light source), and an aperture (opening member) and a projection optical system (also referred to as a projection system) which may include a projection lens are disposed in sequence from one side of the lens on the optical path of light passing through the lens. An image forming unit (not shown) that forms an image using light is disposed on the optical path of light between the lens and the projection lens. That is, Configuration Example 1 of an image display device has a configuration example 1 in which an image forming unit, an aperture, and a projection lens are added to a light source device (see Configuration Example 1 of FIG. 1 ). Fig.14B). In configuration example 1 of the image display device, the intensity distribution of the radiated light radiated from the LD and passing through the lens shows a gentle Gaussian distribution, the integrated light amount which is the integrated value of the light amount of the radiated light is reduced, and the spot diameter of the main lobe of the light passing through the image forming unit, the aperture, and the projection lens is also reduced. Therefore, configuration example 1 of the image display device can achieve efficiency reduction and resolution enhancement without using optical components such as attenuation filters. In this way, when a lens with a smaller NA is used, the amount of projected light can be reduced and the spot diameter of the light used for image display can be reduced (resolution enhancement).

[0154] Fig.16 A is a view showing an image display device according to Comparative Example 7. Fig.16 B is a view showing an image display device according to Comparative Example 8. Fig.16 C is a view showing configuration example 2 of the image display device according to the present technology.

[0155] like Fig.16 As shown in FIG. 1A , in the image display device according to Comparative Example 7, a lens having a large NA (for example, NA>0.16) is disposed on the optical path of light radiated from the LD, and an aperture (opening member) and a projection lens are disposed in sequence from one side of the lens on the optical path of light passing through the lens. An image forming unit (not shown) that forms an image using light is disposed on the optical path of light between the lens and the projection lens. That is, the image display device according to Comparative Example 5 has a configuration in which the image forming unit, the aperture, and the projection lens are added to the light source device according to Comparative Example 4 (see FIG. 1B ). Fig.14 A). In the image display device according to Comparative Example 7, the intensity distribution of the radiated light radiated from the LD and passing through the lens shows a steep Gaussian distribution, the integrated light amount as the integrated value of the light amount of the radiated light increases, and the spot diameter of the main lobe of the light passing through the image forming unit, the aperture, and the projection lens also increases. Therefore, it is possible to achieve efficiency improvement in the image display device according to Comparative Example 5, but there is room for improvement in terms of resolution enhancement.

[0156] like Fig.16 As shown in FIG. 2B , in the image display device according to Comparative Example 8, a large-diameter lens having a large NA (for example, NA>0.16) is disposed on the optical path of light radiated from the LD, and a large-diameter aperture (opening member) and a large-diameter projection lens having a high magnification (refractive power) are disposed on the optical path of light passing through the lens. An image forming unit (not shown) that forms an image using light is disposed on the optical path of light between the lens and the projection lens. That is, the image display device according to Comparative Example 8 has a configuration in which an image forming unit, an aperture, and a projection lens having a large diameter and a high magnification are added to the light source device according to Comparative Example 4 (see FIG. 4 ). Fig.14A) configuration, and the diameter of the lens increases. In the image display device according to Comparative Example 8, the intensity distribution of the radiated light radiated from the LD and passing through the large-diameter lens shows a steep Gaussian distribution, the peripheral light quantity ratio becomes higher, and the integrated light quantity as the integrated value of the light quantity of the radiated light becomes larger, but the spot diameter of the main lobe of the light passing through the image forming unit, the aperture, and the projection lens with a high magnification is reduced. Therefore, it is possible to achieve efficiency improvement and resolution enhancement in the image display device according to Comparative Example 8, but the size of the lens, the aperture, and the projection lens increases, which leads to an increase in cost.

[0157] like Fig.16 As shown in FIG. 3 , in Configuration Example 2 of an image display device according to the present technology, a lens (optical system) having a small NA (for example, NA ≤ 0.16) and a long focal length is provided on the optical path of light radiated from an LD (light source), and an aperture (opening member) and a projection optical system which may include a projection lens are provided on the optical path of light passing through the lens. An image forming unit (not shown) that forms an image using light is provided on the optical path of light between the lens and the projection lens. That is, Configuration Example 2 of an image display device has a configuration example 1 (see FIG. 3 ) in which an image forming unit, an aperture, and a projection lens are added to a light source device. Fig.14 B) configuration, and the focal length of the lens is increased. In configuration example 2 of the image display device, the intensity distribution of the radiated light radiated from the LD and passing through the lens shows a gentle Gaussian distribution, the integrated light amount as the integrated value of the light amount of the radiated light is reduced, and the spot diameter of the main lobe of the light passing through the image forming unit, the aperture, and the projection lens is also reduced. Therefore, configuration example 2 of the image display device can achieve efficiency reduction and resolution enhancement without using optical components such as attenuation filters. In this way, when a lens with a small NA and a long focal length is used, the amount of projection light can be reduced and the spot diameter of the light passing through the projection lens can be reduced (enhanced resolution).

[0158] Fig.17 is a view showing an image display device according to Comparative Example 9. Fig.17 As shown, in the image display device according to Comparative Example 9, a lens having a large NA (for example, NA>0.16) is disposed on the optical path of light radiated from the LD, and a condenser lens and a projection lens are disposed in sequence from one side of the lens on the optical path of light passing through the lens. An image forming unit (not shown) that forms an image using light is disposed on the optical path of light between the lens and the projection lens. That is, the image display device according to Comparative Example 9 has a configuration in which the image forming unit, the condenser lens, and the projection lens are added to the light source device according to Comparative Example 4 (see Fig.14A). In the image display device according to Comparative Example 9, the intensity distribution of the radiated light radiated from the LD and passing through the lens shows a steep Gaussian distribution, the peripheral light quantity ratio increases, and the integrated light quantity which is the integrated value of the light quantity of the radiated light increases, but since the intermediate image forming point is formed on the optical path between the condenser lens and the projection lens, the spot diameter of the main lobe of the light passing through the projection lens decreases. Therefore, it is possible to achieve efficiency improvement and resolution enhancement in the image display device according to Comparative Example 9, but a condenser lens is required as an additional component, which leads to an increase in cost.

[0159] According to the configuration examples 1 and 2 of the image display device of the present technology described above, by reducing the NA of the lens, the spread of the light intensity distribution after being transmitted through the projection lens can be reduced, and as a result, the spot diameter of the main lobe can be reduced. That is, according to the configuration examples 1 and 2 of the image display device, the spot diameter of the light used for image display can be reduced (enhanced resolution) without increasing the size of the lens or adding optical components.

[0160] Note that in Configuration Examples 1 and 2 of the image display device, another laser such as VCSEL (Voltage Surface Emitting Laser) may be used instead of the LD as a light source.

[0161] (Principle of resolution enhancement)

[0162] Fig.18 A is a graph showing the low spatial frequency (1 / T L ) view of the shadow of the wave. Fig.18 B shows the high spatial frequency (1 / T S ) is a view of the shadow of the wave. When the spot diameter of the radiated light is set to be smaller, waves with a higher spatial frequency can be generated and the resolution can be improved.

[0163] <4. Features 1 of this technology>

[0164] (Numerical aperture setting)

[0165] Fig.19 is a diagram showing the relationship between the sum of radiation angles, numerical aperture, and efficiency (Part 1). Fig.19 In the figure, the horizontal axis represents the total radiation angle [degrees], the vertical axis represents the numerical aperture (NA), and the efficiency v is expressed in %. Fig.19As shown, under the condition that the sum of radiation angles is constant, the efficiency v (v1 / v0) increases with the increase of NA and decreases with the decrease of NA. In addition, under the condition that NA is constant, the efficiency v decreases with the increase of the sum of radiation angles and increases with the decrease of the sum of radiation angles. Regardless of the purpose, the collimator lens and the condenser lens of the prior art need to have high efficiency, and therefore, the collimator lens and the condenser lens with NA of 0.17 or more are used. Specifically, the NA of the collimator lens of the light source device for communication in the prior art is about 0.17 to 0.30. The NA of the collimator lens of the light source device for the optical pickup (OPU) in the prior art is about 0.22 to 0.30. The NA of the collimator lens for the projector in the prior art is about 0.24 to 0.26. The NA of the condenser lens for the projector in the prior art is about 0.40 to 0.60.

[0166] Therefore, in the light source device (e.g., configuration example 1 of the light source device) and the image display device (e.g., configuration examples 1 and 2 of the image display device) according to the present technology, the numerical aperture (NA) of the lens is set to 0.16 or less. Therefore, for example, in the case where the light source device and the image display device are used for direct retinal projection, the amount of light can be reduced without using an optical filter such as an ND filter, and the safety of the retina can be ensured. In addition, for example, in the case where the light source device and the image display device are used for projection in a dark environment, the amount of light can be reduced without using an optical filter such as an ND filter, and the need to reduce the amount of unnecessary light can also be dealt with in advance.

[0167] Fig. 20 A is a diagram showing the relationship between the numerical aperture (NA), the peripheral light quantity ratio, and the projection light quantity. In particular, in applications for direct retinal projection, it is necessary to reduce the projection light quantity as much as possible and increase the peripheral light quantity ratio as much as possible, and therefore, an NA of 0.16 or less is effective (see Fig. 20 A).

[0168] Fig. 20 B is a diagram showing the relationship between the data aperture (NA) and the volume ratio. Fig. 20 B shows the relationship between NA and device volume when the device volume is 1.0 assuming that NA is 0.24. When the NA of the lens becomes smaller, the focal length F becomes longer, and the device tends to be larger. Therefore, for example, from the perspective of reducing the volume ratio, NA is preferably 0.03 or more. Therefore, the volume ratio can be suppressed to 4.0 or less.

[0169] Fig.21 A is a diagram showing the relationship among the data aperture (NA), the adjustment sensitivity, and the amount of projection light. Fig.21B is a diagram showing the relationship between the data aperture and the change in the amount of light due to accommodation (positional deviation and angle deviation between the light source and the lens). In particular, in applications for direct retinal projection, a smaller NA is required from the perspective of reducing the amount of projected light, but the accommodation sensitivity increases as the NA decreases (see Fig.21 A). As the adjustment sensitivity increases, the light quantity variation due to errors (positional deviation and angular deviation between the light source and the lens) increases (see Fig.21 B), the difference from the light amount as the target (target light amount) increases. Therefore, it is preferable to set NA to a value with which the light amount change due to adjustment is small. Specifically, for example, NA is preferably set to 0.05 or more. Therefore, the light amount change due to adjustment can be suppressed to 1.0% or less. The details of the adjustment sensitivity will be described later.

[0170] (Setting the total radiation angle)

[0171] In the light source device and the image display device according to the present technology, the sum of the radiation angles of the light source (eg, LD) is set to 14° or more. In the case where the NA is 0.16 or less and the sum of the radiation angles is 14° or more, the efficiency v can be suppressed to 95% or less (see Fig.19 ).

[0172] From the perspective of reducing the efficiency v, it is more preferable that the sum of the radiation angles is larger. For example, in the case where the NA is 0.16 or less and the sum of the radiation angles is 18° or more, the efficiency v can be suppressed to 90% or less (see Fig.19 ). For example, in the case where NA is 0.16 or less and the sum of the radiation angles is 22° or more, the efficiency v can be suppressed to 80% or less (see Fig.19 ). For example, in the case where NA is 0.16 or less and the sum of the radiation angles is 26° or more, the efficiency v can be suppressed to 70% or less (see Fig.19 ). For example, in the case where NA is 0.16 or less and the sum of the radiation angles is 31° or more, the efficiency v can be suppressed to 60% or less (see Fig.19 ). For example, in the case where NA is 0.16 or less and the sum of the radiation angles is 37° or more, the efficiency v can be suppressed to 50% or less (see Fig.19 ).

[0173] although Fig.19 The range in which the sum of the radiation angles is 44° or less is shown, and the sum of the radiation angles may exceed 44°. In this case, the efficiency v may be further reduced.

[0174] <5. Feature 2 of this technology>

[0175] (Numerical aperture setting)

[0176] Fig. 22 is a diagram showing the relationship between the sum of radiation angles, numerical aperture, and efficiency (Part 2). Fig. 22 In the figure, the horizontal axis represents the total radiation angle [degrees], the vertical axis represents the numerical aperture (NA), and the efficiency v is expressed in %. In addition to the different setting ranges of the numerical aperture, Fig. 22 is with Fig.19 Similar view.

[0177] like Fig. 22 As shown, in the light source device (e.g., configuration example 1 of the light source device) and the image display device (e.g., configuration examples 1 and 2 of the image display device) according to the present technology, the numerical aperture (NA) of the lens is preferably set to 0.06 or less. In this case, when the sum of the radiation angles is 14° or more, the efficiency v can be suppressed to 60% or less.

[0178] Fig.23 is a diagram showing the relationship between numerical aperture and light intensity distribution. Fig.23 As shown, in the laser light emitted from the LD, regardless of the numerical aperture (NA), the light intensity distribution of the lens opening portion (near field pattern) shows a horizontally long ellipse, and the light intensity distribution of the projection portion (far field pattern) shows a vertically long ellipse. Fig.23 Examples of NA settings of 0.248, 0.125, and 0.083 are shown. Fig.23 It can be seen that the spot diameter in the longitudinal cross-section of both the lens opening portion and the projection portion can be reduced as the NA decreases. Fig.23 It can be seen that the spot diameter in the transverse cross-section of both the lens opening portion and the projection portion can be reduced as the NA decreases (however, there is no difference between the case where the NA is 0.125 and the case where the NA is 0.083).

[0179] (Example)

[0180] As a specific example of a light source device (e.g., configuration example 1 of the light source device) and an image display device (e.g., configuration examples 1 and 2 of the image display device) according to the present technology, a lens with an NA of 0.06 and an LD with a total radiation angle of 29° are used. As a result, the efficiency v can be reduced to 8%. That is, the safety of image viewing using direct retinal projection can be ensured without using an ND filter, and the effect of improving the resolution of the projected image is obtained in image viewing. It has been confirmed that in this example, unnecessary stray light that does not pass through the lens is generated by using a lens with a smaller NA. As a countermeasure, the housing to be used is subjected to anti-reflection treatment (surface roughness treatment or application of an absorbing material), and an aperture (opening member) corresponding to the lens opening portion is installed to reduce the influence of unnecessary light on the image light, so that the goal can be achieved without reducing the viewing experience.

[0181] <6. Feature 3 of this technology>

[0182] (Numerical aperture setting)

[0183] Fig.24 is a diagram showing the relationship between the sum of radiation angles, numerical aperture, and efficiency (Part 3). Fig.24 In the figure, the horizontal axis represents the total radiation angle [degrees] and the vertical axis represents the numerical aperture (NA). Except for the different setting ranges of the numerical aperture and the fact that the efficiency v is not indicated, Fig.24 is with Fig.19 and Fig. 22 Similar view.

[0184] exist Fig.24 In the figure, the area surrounded by the thick black line is the area that requires high adjustment accuracy. When the xy coordinate (x, y) is set with the sum of the radiation angles on the x-axis and the NA on the y-axis, this area is the area in the graph with three coordinates (14°, 0.001), (14°, 0.09), and (23°, 0.001) as vertices.

[0185] When (x, y) is within this area, the adjustment sensitivity becomes very high, and the light amount changes greatly with respect to the position deviation and angle deviation between the light source and the lens. Therefore, it is necessary that (x, y) is a combination with a smaller y (NA) value that deviates from this area in order to reduce the adjustment sensitivity while achieving efficiency reduction and resolution enhancement.

[0186] For example, preferably, y (numerical aperture) is 0.09 or less, and x (sum of radiation angles) is 14° or more. In this case, a suitable (x, y) outside the region may be selected.

[0187] For example, the numerical aperture may be 0.16 or less, and the sum of the radiation angles may be 23° or more. In this case, a more appropriate (x, y) outside the region may also be selected.

[0188] For example, the numerical aperture may be 0.09 or less, and the sum of the radiation angles may be 23° or more. In this case, a more appropriate (x, y) outside the region may also be selected.

[0189] <7. Adjust sensitivity>

[0190] Fig.25 1 is a diagram showing the positional relationship between the light source (LD) and the lens in each of the light source device of the prior art and the light source device of the present technology. Fig.25 As shown, in the present technology, the numerical aperture of the lens is smaller (NA>NA') and the focal length is longer (F<F') than in the prior art, and the adjustment stroke between the LD and the lens becomes larger (F × tanθ <F' × tanθ). That is, in the present technology, the position deviation allowable range, which is the allowable range of the position deviation between the LD and the lens (in which all the light from the LD is focused), is wider and more robust than in the prior art. It should be noted that in the case where the position deviation between the LD and the lens exceeds the position deviation allowable range, for example, tilt adjustment (angle adjustment) can be performed for correction.

[0191] Fig.26 1 is a diagram describing the adjustment sensitivity of a light source device of the related art (when the position deviation and the angle deviation are small). Fig.26 The middle left figure shows an ideal state (without positional deviation and angular deviation) in which the optical axis of the LD and the optical axis of the lens (lens with a larger NA) coincide with each other. Fig.26 The middle right figure shows a state (tilt adjustment state) in which a small positional deviation D exceeding the above allowable range occurs between the optical axis of LD and the optical axis of the lens (lens with a larger NA) and the optical axis of LD is tilted at a small angle to pass through the center of the lens. Fig.26 When comparing the left and right figures in FIG. 1 , it can be seen that the difference in the integrated light amount of the light transmitted through the lens is small. That is, in the light source device of the prior art, the change in the light amount relative to the small position deviation D and the small angle deviation is small.

[0192] Fig. 27 It is a diagram describing the adjustment sensitivity of the light source device of the present technology (when the position deviation and the angle deviation are small). Fig. 27 The left view shows an ideal state in which the optical axis of the LD and the optical axis of the lens (lens with a smaller NA) coincide with each other. Fig. 27The right figure shows a state (tilt adjustment state) in which a small positional deviation D occurs between the optical axis of the LD and the optical axis of the lens (lens with a small NA) and the optical axis of the LD is tilted at a small angle to pass through the center of the lens. Fig. 27 When the left and right images in FIG. 1 are compared, it can be seen that the difference in the integrated light amount of the light transmitted through the lens is large. That is, in the light source device of the present technology, the light amount changes greatly with respect to small position deviation D and small angle deviation.

[0193] Fig.28 A diagram illustrating the adjustment sensitivity of a light source device of the prior art in the case of large positional and angular deviations. Fig.28 The middle left figure shows an ideal state (without positional deviation and angular deviation) in which the optical axis of the LD and the optical axis of the lens (lens with a larger NA) coincide with each other. Fig.28 The middle right figure shows a state (tilt adjustment state) in which a large positional deviation D occurs between the optical axis of the LD and the optical axis of the lens (lens with a large NA) and the optical axis of the LD is tilted at a large angle to pass through the center of the lens. Fig.28 When comparing the left and right figures in FIG. 1 , it can be seen that the difference in the integrated light amount of the light transmitted through the lens is small. That is, in the light source device of the prior art, the change in the light amount relative to large position deviation and large angle deviation is small.

[0194] Fig.29 It is a diagram describing the adjustment sensitivity of the light source device of the present technology (when the position deviation and the angle deviation are small). Fig.29 The left figure shows an ideal state in which the optical axis of the LD and the optical axis of the lens (lens with a smaller NA) coincide with each other. Fig.28 The right figure shows a state (tilt adjustment state) in which a large positional deviation D occurs between the optical axis of LD and the lens (optical axis of the lens with a smaller NA) and the optical axis of LD is tilted at a large angle to pass through the center of the lens. Fig.29 When comparing the left and right images in FIG. 1 , it can be seen that the difference in the integrated light amount of light transmitted through the lens is large. That is, in the light source device of the present technology, the light amount changes greatly with respect to large position deviation and large angle deviation.

[0195] From the above description, it can be seen that, for example, in the case where the positional deviation between the LD and the lens exceeds the positional deviation allowable range and tilt adjustment is performed, the light amount variation due to the angle deviation between the LD and the lens is greater in the present technology using a lens with a smaller NA than in the prior art using a lens with a larger NA. It is considered that the light amount variation increases as the NA decreases and the sum of the radiation angles decreases. In particular, Fig.24In the region surrounded by the medium thick black line, the light amount varies greatly, and therefore it is very effective to set the NA and the total radiation angle so that the combination of NA and the total radiation angle does not fall within this region.

[0196] <8. Configuration Examples 3 to 5 of the Image Display Device According to the Present Technology>

[0197] (Configuration Example 3 of Image Display Device)

[0198] Fig.30 : is a view showing a configuration example 3 of the image display device according to the present technology. Fig.31 It shows Fig.30 A block diagram of the functions of an image display device. Configuration example 3 of the image display device is an image display device for direct retinal projection. Fig.30 and Fig.31 As shown, configuration example 3 of the image display device includes a light source device, a MEMS mirror (optical deflector) as an image forming unit, a projection lens as a projection optical system, an eyepiece as an eye optical element, and a control unit. At least the eye optical element of configuration example 3 of the image display device is integrally supported by a support structure (e.g., a glasses frame) mounted on the head (including a part of the face) of the user. The system including the light source device, the MEMS mirror, and the projection lens may be integrally supported by the support structure, or may be provided in a main body separated from the support structure (e.g., in a fixed housing).

[0199] Configuration example 3 of the image display device includes multiple (for example, three) light sources with different emission wavelengths, multiple lenses are arranged to correspond to the multiple light sources, and the optical system of the light source device includes a combining unit, which includes first to third reflectors and combines light beams emitted from the multiple light sources and passing through corresponding lenses.

[0200] (Light source device)

[0201] The light source device of Configuration Example 3 includes first to third LDs, first to third lenses, first to fourth reflecting mirrors, a monitor PD, an LD driver, and a housing in which these components are housed.

[0202] The first LD to the third LD are LDs that emit red (R) light, blue (G) light, and green (B) light, respectively. The sum of the radiation angles of each of the LDs is 14° or greater. Each of the lenses is a lens having an NA of 0.16 or less (e.g., a spherical lens or an aspherical lens). For example, each of the lenses is a collimator lens (also referred to as a collimating lens).

[0203] The first lens is disposed on an optical path of red light emitted from the first LD. The first reflector is a dichroic mirror that reflects red light. The first reflector is disposed on an optical path of red light emitted from the first LD and transmitted through the first lens.

[0204] The second lens is disposed on the optical path of the green light emitted from the second LD. The second reflector is a dichroic mirror that transmits red light and reflects green light. The second reflector is disposed at an intersection between the optical path of the red light reflected from the first reflector and the optical path of the green light emitted from the second LD and transmitted through the second lens.

[0205] The third lens is disposed on the optical path of the blue light emitted from the third LD. The third reflector is a dichroic mirror that transmits red light and green light and reflects blue light. The third reflector is disposed at an intersection between the optical path of the combined light of the red light and the green light passing through the second reflector and the optical path of the blue light emitted from the third LD and transmitted through the third lens.

[0206] The combined light of red light, green light and blue light passing through the third reflector is incident on the fourth reflector. The fourth reflector is a half reflector that transmits a portion of the incident light and reflects another portion. The monitor PD is disposed on the optical path of the light transmitted through the fourth reflector. For example, the monitor PD includes a photodiode (PD).

[0207] For example, the LD driver includes circuit elements such as capacitors and transistors.

[0208] (Image forming unit)

[0209] The MEMS mirror as an image forming unit is arranged on the optical path of the combined light reflected by the fourth reflector and forms an image using the combined light. The MEMS mirror includes a reflector portion that can rotate around two different axes. The MEMS mirror is synchronously controlled by a control unit (also referred to as a controller) and the LD. It should be noted that the housing is provided with a light-transmitting window that transmits the combined light reflected by the fourth reflector toward the MEMS mirror.

[0210] The control unit generates a light emission control signal for causing each of the LDs to emit light based on the input image information, and outputs the light emission control signal to the LD driver. The LD driver generates a drive signal for driving each of the LDs based on the light emission control signal, and applies the drive signal to the corresponding LD. The control unit controls the light emission amount of the LD based on an output signal of a monitor PD (APC: automatic power control). For example, the control unit includes a CPU, an FPGA, a chipset, etc.

[0211] (Projection optical system)

[0212] The projection lens may be part of a projection optical system that projects image-forming light from the MEMS mirror. More specifically, the projection lens is disposed on an optical path of light deflected by the MEMS mirror and converts the light into substantially parallel light.

[0213] (Ocular Optics)

[0214] The eye optical element is disposed on the optical path of the light converted into substantially parallel light by the projection lens, and guides the light passing through the projection optical system to the eyeball of the user. For example, an eyepiece is used as the eye optical element.

[0215] In the above-described Configuration Example 3 of the image display device, a full-color image display device can be provided that exhibits effects similar to those of Configuration Examples 1 and 2 of the image display device.

[0216] (Configuration Example 4 of Image Display Device)

[0217] Fig.32 : is a view showing a configuration example 4 of an image display device according to the present technology. Configuration example 4 of the image display device is an image display device for direct retinal projection. Fig.32 As shown, configuration example 4 of the image display device has a configuration similar to configuration example 3 of the image display device except that the image forming unit includes a DMD (digital micromirror device) instead of a MEMS mirror. Configuration example 4 of the image display device has similar effects to configuration example 3 of the image display device described above.

[0218] (Configuration Example 5 of Image Display Device)

[0219] Fig.33 : is a view showing a configuration example 5 of an image display device according to the present technology. Configuration example 5 of the image display device is an image display device for direct retinal projection. Fig.33 As shown, configuration example 5 of the image display device has a configuration similar to configuration example 3 of the image display device, except that a plurality of LDs serving as liquid crystal elements are arranged to correspond to a plurality of (for example, three) lenses, and an image forming unit causes light passing through each of the plurality of lenses to be incident on the liquid crystal element corresponding to the lens, and combines the light passing through the liquid crystal elements.

[0220] In Configuration Example 5 of the image display device, the light source device includes first to third LDs and first to third lenses, and the image forming unit includes first to fourth dichroic prisms (DPs), first to third liquid crystal displays (LCDs), and first and second reflecting mirrors.

[0221] The first DP (first dichroic prism) that reflects the red light emitted from the first LD and passed through the first lens is disposed on the optical path of the red light. The first LCD (first liquid crystal display) is disposed on the optical path of the red light reflected by the first DP. The first LCD is a reflective liquid crystal element, and forms an image using the incident red light. The red light that has been reflected by the first LCD and forms an image is transmitted through the first DP, reflected by the first reflector, and incident on the fourth DP (cross dichroic prism).

[0222] The second DP (second dichroic prism) that reflects the green light emitted from the second LD and passed through the second lens is disposed on the optical path of the green light. The second LCD (second liquid crystal display) is disposed on the optical path of the green light reflected by the second DP. The second LCD is a reflective liquid crystal element, and forms an image using the incident green light. The green light that has been reflected by the second LCD and forms an image is transmitted through the second DP and is incident on the fourth DP.

[0223] A third DP (third dichroic prism) that reflects the blue light emitted from the third LD and passed through the third lens is disposed on the optical path of the blue light. A third LCD (third liquid crystal display) is disposed on the optical path of the blue light reflected by the third DP. The third LCD is a reflective liquid crystal element, and forms an image using the incident blue light. The blue light that has been emitted by the third LCD and forms an image is transmitted through the third DP, reflected by the second reflector, and incident on the fourth DP.

[0224] The cross dichroic prism serving as the fourth DP combines the red light passing through the first reflector, the green light passing through the second DP, and the blue light passing through the second reflector, and emits the combined light thereof.

[0225] A projection lens as a projection optical element is disposed on the optical path of the combined light from the fourth DP. An eyepiece as an eye optical element is disposed on the optical path of the combined light passing through the projection lens.

[0226] The above-described Configuration Example 5 of the image display device has similar effects to those of Configuration Example 3 of the image display device.

[0227] <9. Volume of the light source device according to the present technology and the light source device according to the prior art>

[0228] Fig.34 This is a diagram comparing the volumes of a light source device of the prior art and a light source device of the present technology. Fig.34 The light source device of the present technology shown in the right view of has a configuration similar to that of the light source devices in configuration examples 3 and 4 of the image display device (a configuration in which the NA of the first to third lenses is 0.16 or less). Fig.34The light source device of the related art shown in the left view of has a configuration substantially similar to that of the light source devices in configuration examples 3 and 4 of the image display device, except that the NA of the first to third lenses is greater than 0.16. The device volume of the light source device can be expressed by V = C × B × (A + F), which uses Fig.34 The dimensions A and B in the direction perpendicular to the paper surface, the dimension C in the direction perpendicular to the paper surface, and the focal length F of each of the lenses. Therefore, the focal length of each of the lenses of the light source device of the present technology is longer than that of each of the lenses of the light source device of the prior art, and the volume of the device increases accordingly. Therefore, in order to suppress the above-mentioned focal length, it is preferable to set NA to, for example, 0.03 or more.

[0229] <10. Image display device according to first to ninth embodiments of the present technology>

[0230] Hereinafter, image display devices according to first to ninth embodiments of the present technology will be described.

[0231] (Image Display Device According to First Embodiment)

[0232] Fig.35 1 is a diagram showing an image display device 10 according to a first embodiment of the present technology. The image display device 10 is a projector. Fig.35 As shown, the image display device 10 has the same configuration example 3 of the image display device (see Fig.30 ) is a configuration basically similar to that of the image display device 10. The image display device 10 includes a light source device 100, a MEMS mirror 201, and a projection lens 301. The light source device 100 includes first to third LDs 101a, 101b, and 101c, first to third lenses 102a, 102b, and 102c, first to fourth mirrors 103a, 103b, 103c, and 104, and a housing 100a that accommodates these components. Light emitted from the light source device 100 and sequentially passing through the MEMS mirror 201 and the projection lens 301 forms an image on a predetermined display surface (e.g., a screen surface, a wall surface of a building, or a ceiling surface). Note that the image display device 10 may include a monitor PD (see Fig.30 ). According to the image display device 10, it is possible to provide a projector that can cope with the excessive amount of light from the LD (particularly suitable for use in a dark environment) and can perform high-resolution display.

[0233] (Image Display Device According to Second Embodiment)

[0234] Fig.36 2 is a diagram showing an image display device 20 according to a second embodiment of the present technology. The image display device 20 is a projector. Fig.36As shown, the image display device 20 has the same configuration example as the image display device 4 (see Fig.32 ) is basically similar to the configuration of the image display device 20. The image display device 20 includes a light source device 100, a digital mirror device (DMD) 202, and a projection lens 301. Light emitted from the light source device 100 and sequentially passing through the DMD 202 and the projection lens 301 forms an image on a predetermined display surface (e.g., a screen surface, a wall surface of a building, or a ceiling surface). It should be noted that the image display device 20 may include a monitor PD (see Fig.32 According to the image display device 20, it is possible to provide a projector that can cope with the excessive amount of light from the LD (particularly suitable for use in a dark environment) and can perform high-resolution display.

[0235] (Image Display Device According to Third Embodiment)

[0236] Fig.37 1 is a diagram showing an image display device 30 according to a third embodiment of the present technology. The image display device 30 is a projector. Fig.37 As shown, the image display device 30 has the same configuration as the image display device example 5 (see Fig.33 ) is basically similar to the configuration of the image display device 30. The light source device of the image display device 30 includes the first to third LDs 101a, 101b and 101c and the first to third lenses 102a, 102b and 102c. The image forming unit of the image display device 30 includes the first to fifth dichroic prisms 105a, 105b, 105c, 105d and 105e, the first to third LCDs 106a, 106b and 106c and the first and second reflecting mirrors 107 and 108. The projection optical system of the image display device 30 includes a projection lens 301.

[0237] The red light emitted from the first LD 101a and transmitted through the first lens 102a is reflected by the first dichroic prism 105a toward the first LCD 106a. The red light reflected by the first LCD 106a and forming an image is reflected by the first reflection mirror 107 and incident on the fifth dichroic prism 105e.

[0238] The green light emitted from the second LD 101b and transmitted through the second lens 102b is reflected by the second dichroic prism 105b toward the second LCD 106b. The green light reflected by the second LCD 106b and forming an image is transmitted through the fourth dichroic prism 105d and incident on the fifth dichroic prism 105e.

[0239] The blue light emitted from the third LD 101c and transmitted through the third lens 102c is reflected by the third dichroic prism 105c toward the third LCD 106c. The blue light reflected by the third LCD 106c and forming an image is reflected by the second reflecting mirror 108, reflected by the fourth dichroic prism 105d, and incident on the fifth dichroic prism 105e.

[0240] The red light, green light, and blue light incident on the fifth dichroic prism 105 e are combined by the fifth dichroic prism 105 e and form an image on a predetermined display surface (eg, a screen surface, a wall surface of a building, or a ceiling surface) through the projection lens 301 .

[0241] According to the above-described image display device 30 , it is possible to provide a projector that can cope with the excessive amount of light from the LD (particularly suitable for use in a dark environment) and can perform high-resolution display.

[0242] (Image Display Device According to Fourth Embodiment)

[0243] Fig.38 4 is a diagram showing an image display device 40 according to a fourth embodiment of the present technology. The image display device 40 is an image display device for direct retinal projection. Fig.38 As shown, the image display device 40 has the same configuration as the image display device 10 according to the first embodiment (see Fig.35 ) basically similar configuration.

[0244] In the image display device 40, the light passing through the projection lens 301 forms an intermediate image forming point on the optical path between the projection lens 301 and the eyepiece 401. The light passing through the eyepiece 401 forms an image on the retina of the eyeball EB.

[0245] According to the image display device 40 , it is possible to provide an image display device for direct retinal projection that can cope with an excessive amount of light of LD (particularly contributing to eye safety) and that can perform high-resolution display.

[0246] (Image Display Device According to Fifth Embodiment)

[0247] Fig.39 1 is a view showing an image display device 50 according to a fifth embodiment of the present technology. The image display device 50 is an image display device for direct retinal projection. Fig.39 As shown, the image display device 50 has the same configuration as the image display device 20 according to the second embodiment (see Fig.36 ) basically similar configuration.

[0248] In the image display device 50, the light passing through the projection lens 301 forms an intermediate image forming point on the optical path between the projection lens 301 and the eyepiece 401. The light passing through the eyepiece 401 forms an image on the retina of the eyeball EB.

[0249] According to the image display device 50, it is possible to provide an image display device for direct retinal projection that can cope with excessive light amounts of processing LDs (particularly contributing to eye safety) and that is capable of high-resolution display.

[0250] (Image Display Device According to Sixth Embodiment)

[0251] Fig.40 1 is a diagram showing an image display device 60 according to a sixth embodiment of the present technology. The image display device 60 is an image display device for direct retinal projection. Fig.40 As shown, the image display device 60 has the same features as the image display device 30 according to the third embodiment (see Fig.37 In the image display device 60, light passing through the projection lens 301 as a projection optical system forms an image on the retina of the eyeball EB through the eyepiece 401.

[0252] According to the image display device 60 , it is possible to provide an image display device for direct retinal projection that can cope with excessive light amount of LD (particularly helpful for eye safety) and can perform high-resolution display.

[0253] (Image Display Device According to Seventh Embodiment)

[0254] Fig.41 : is a view showing an image display device 70 according to a seventh embodiment of the present technology. The image display device 70 is an image display device for direct retinal projection. Fig.41 As shown, the image display device 70 has the same configuration as the image display device 40 according to the fourth embodiment (see FIG. 1 ), except that a light-condensing optical element 501 as an image forming unit is further provided on the optical path of light between the light source device 100 and the MEMS mirror 201. Fig.38 ) basically similar configuration.

[0255] The focusing optical element 501 focuses (images) the light from the light source device 100 on the MEMS mirror 201. Therefore, the resolution of the image formed on the retina of the eyeball EB can be further increased. In addition, a MEMS mirror 201 with a small size can be used. For example, as the focusing optical element 501, a focusing mirror can be used in addition to a focusing lens.

[0256] According to the image display device 70 , it is possible to provide an image display device for direct retinal projection that can cope with excessive light amount of LD (particularly helpful for eye safety) and can perform high-resolution display.

[0257] (Image Display Device According to Eighth Embodiment)

[0258] Fig.42 1 is a diagram showing an image display device 80 according to an eighth embodiment of the present technology. The image display device 80 is an image display device for direct retinal projection. Fig.42 As shown, the image display device 80 has the same configuration as the image display device 50 according to the fifth embodiment (see FIG. 1 ), except that a light-condensing optical element 501 as an image forming unit is further provided on the optical path of light between the light source device 100 and the DMD 202. Fig.39 ) basically similar configuration.

[0259] The focusing optical element 502 focuses (images) the light from the light source device 100 on the optical path of the light between the focusing optical element 502 and the DMD 202, and makes the light incident on the DMD 202 as diffused light. Therefore, the resolution of the image formed on the retina of the eyeball EB can be further increased. For example, as the focusing optical element 501, a focusing reflector can be used in addition to a focusing lens.

[0260] According to the image display device 70 , it is possible to provide an image display device for direct retinal projection that can cope with excessive light amount of LD (particularly helpful for eye safety) and can perform high-resolution display.

[0261] (Image Display Device According to Ninth Embodiment)

[0262] Fig.43 1 is a diagram showing an image display device 90 according to a ninth embodiment of the present technology. The image display device 90 is an image display device for direct retinal projection. Fig.43 As shown, the image display device 90 has the same configuration as the image display device 60 according to the sixth embodiment (see Fig.40 ) basically similar configuration.

[0263] In the image display device 90, a condensing optical element 302 is provided between the image forming unit and the projection lens 301. The condensing optical element 302 condenses (images) the light forming the image from the image forming unit on the optical path between the condensing optical element 302 and the projection lens 301 to form an intermediate image forming point. The diffused light from the intermediate image forming point is converted into substantially parallel light by the projection lens 301, and forms an image on the retina of the eyeball EB through the eyepiece 401. Examples of the condensing optical element 302 include a condensing lens and a condensing reflecting mirror.

[0264] In the image display device 90, the intermediate image forming point is formed in the projection optical system 300, so the resolution of the image projected on the retina of the eyeball EB can be further improved. For example, as the condensing optical element 302, a condensing mirror can be used in addition to a condensing lens.

[0265] According to the image display device 90 , it is possible to provide an image display device for direct retinal projection that can cope with excessive light amount of LD (particularly helpful for eye safety) and can perform high-resolution display.

[0266] It should be noted that the light-condensing optical element 302 in the image display device 90 may be disposed on the optical path of light between the projection lens 301 and the eyepiece 401 .

[0267] <11. Modification examples of the present technology>

[0268] The above-described configuration example 1 of the light source device, the above-described respective configuration examples of the image display device, and the image display device according to the respective embodiments can be appropriately changed.

[0269] For example, a reflective LCD is used as each liquid crystal element in the image forming unit of configuration example 5 of the image display device, the image display device 30 according to the third embodiment, the image display device 60 according to the sixth embodiment, and the image display device 90 according to the ninth embodiment, but a transmissive LCD can also be used as at least one liquid crystal element.

[0270] For example, a contact lens type optical element mounted on the eyeball EB may be used instead of an eye optical element (e.g., an eyepiece) in an image display device for direct retinal projection. In this case, the contact lens type optical element may be a component of the image display device or may not necessarily be a constituent element of the image display device. For example, as the contact lens type optical element, a diffractive optical element (DOE), a holographic optical element (HOE), etc. may be used.

[0271] For example, the light source of the light source device or the image display device is not limited to a semiconductor laser, and may be any light source that can limit the radiation angle, such as a light emitting diode, a halogen lamp, or a laser other than a semiconductor laser. In this case, it is preferred that the sum of the radiation angles is set to 14° or greater.

[0272] For example, a galvano mirror or the like may be used instead of the MEMS mirror as the optical deflector of the image forming unit.

[0273] For example, an eyepiece reflector may be used instead of an eyepiece as the eye optics.

[0274] For example, a projection mirror may be used instead of a projection lens as a projection optical element of the projection optical system.

[0275] For example, Configuration Example 1 of the light source device, each configuration example of the image display device, and the image display device according to each embodiment may be combined with one another within a range not causing any inconsistency.

[0276] Note that the present technology may also have the following configurations.

[0277] (1) A light source device, comprising:

[0278] at least one light source; and

[0279] an optical system disposed on an optical path of light from the light source and comprising a lens,

[0280] The lens has a numerical aperture of 0.16 or less, the total radiation angle of the light source is 14° or more, and the total radiation angle is the sum of radiation angles respectively associated with two directions orthogonal to each other.

[0281] (2) The light source device according to (1), wherein the numerical aperture is 0.09 or less, and the sum of the radiation angles is 14° or more.

[0282] (3) The light source device according to one or more of (1) to (2), wherein the numerical aperture is 0.16 or less, and the sum of the radiation angles is 23° or more.

[0283] (4) The light source device according to one or more of (1) to (3), wherein the numerical aperture is 0.09 or less, and the sum of the radiation angles is 23° or more.

[0284] (5) The light source device according to one or more of (1) to (4), wherein the lens is a spherical lens or an aspherical lens.

[0285] (6) The light source device according to one or more of (1) to (5), wherein the light source includes a semiconductor laser.

[0286] (7) An image display device comprising: the light source device according to one or more of (1) to (6); an image forming unit that forms an image using light from the light source device; and a projection optical system that projects the light that forms the image.

[0287] (8) The image display device according to one or more of (1) to (7), wherein the image forming unit includes an optical deflector.

[0288] (9) The image display device according to one or more of (1) to (8), wherein the image forming unit includes a digital micromirror device.

[0289] (10) The image display device according to one or more of (1) to (9), wherein the image forming unit includes a liquid crystal element.

[0290] (11) An image display device according to one or more of (1) to (10), wherein the at least one light source is a plurality of light sources having different emission wavelengths, a plurality of lenses are arranged to correspond to the plurality of light sources, and the optical system of the light source device combines light beams emitted from the plurality of light sources and passing through corresponding lenses.

[0291] (12) An image display device according to one or more of (1) to (11), wherein the at least one light source is a plurality of light sources having different emission wavelengths, a plurality of lenses are arranged to correspond to the plurality of light sources, a plurality of liquid crystal elements are arranged to correspond to the plurality of lenses, and the image forming unit causes light beams passing through the plurality of lenses to be incident on the liquid crystal elements corresponding to the lenses, respectively, and combines the light beams passing through the liquid crystal elements.

[0292] (13) The image display device according to one or more of (1) to (12), further including an optical element that guides the light passing through the projection optical system to an eyeball of a user.

[0293] (14) The image display device according to one or more of (1) to (13), further including a light-collecting optical element provided on an optical path of light between the light source device and the image forming unit.

[0294] (15) The image display device according to one or more of (1) to (14), wherein the image forming unit includes a digital micromirror device, and the light focusing optical element focuses light on an optical path of light between the light source device and the digital micromirror device.

[0295] (16) The image display device according to one or more of (1) to (15), wherein the image forming unit includes a light polarizer, and the light focusing optical element focuses light on the optical deflector.

[0296] (17) The image display device according to one or more of (1) to (16), wherein the projection optical system includes a condensing optical element.

[0297] (18) The image display device according to one or more of (1) to (17), wherein the projection optical system includes a projection optical element, and the condensing optical element is disposed on an optical path of light between the image forming unit and the projection optical element.

[0298] (19) The image display device according to one or more of (1) to (17), further includes an optical element that guides light passing through the projection optical system to the user's eyeball, wherein the projection optical system includes a projection optical element, and the focusing optical element is arranged on the optical path of the light between the projection optical element and the optical element.

[0299] (20) The image display device according to one or more of (1) to (19), wherein at least the optical element is mounted on a user's head. (twenty one)

[0301] A light source device, comprising:

[0302] Light source; and

[0303] an optical system comprising a lens located in the optical path of light from the light source,

[0304] The lens has a numerical aperture of 0.16 or less, and the light source has a total radiation angle, which is the sum of a first radiation angle measured relative to a first direction and a second radiation angle measured relative to a second direction orthogonal to the first direction. (twenty two)

[0306] The light source device according to (21), wherein the numerical aperture is 0.09 or less, and wherein the sum of the radiation angles is 14° or more. (twenty three)

[0308] The light source device according to one or more of (21) to (22), wherein the numerical aperture is 0.16 or less, and wherein the sum of the radiation angles is 23° or more. (twenty four)

[0310] The light source device according to one or more of (21) to (23), wherein the numerical aperture is 0.09 or less, and wherein the sum of the radiation angles is 23° or more. (25)

[0312] The light source device according to one or more of (21) to (24), wherein the lens is a spherical lens or an aspherical lens. (26)

[0314] The light source device according to one or more of (21) to (25), wherein the light source device includes a laser. (27)

[0316] An image display device, comprising:

[0317] A light source device, comprising:

[0318] Light source; and

[0319] an optical system comprising a lens located in the optical path of light from the light source,

[0320] wherein the lens has a numerical aperture of 0.16 or less, wherein the light source has a sum of radiation angles, the sum of radiation angles being a sum of a first radiation angle measured relative to a first direction and a second radiation angle measured relative to a second direction orthogonal to the first direction;

[0321] an image forming system that forms an image using light from the light source device; and

[0322] A projection system projects the image. (28)

[0324] The image display device according to (27), wherein the image forming system includes an optical deflector. (29)

[0326] The image display device according to one or more of (27) to (28), wherein the image forming system includes a digital micromirror device. (30)

[0328] The image display device according to one or more of (27) to (29), wherein the image forming system includes a liquid crystal element. (31)

[0330] The image display device according to one or more of (27) to (30), further comprising:

[0331] a plurality of light sources emitting light of different wavelengths; and

[0332] a plurality of lenses, the plurality of lenses corresponding to the plurality of light sources,

[0333] The optical system combines the lights from the plurality of light sources that have passed through corresponding lenses. (32)

[0335] The image display device according to one or more of (27) to (31), further comprising:

[0336] a plurality of light sources emitting light of different wavelengths; and

[0337] a plurality of lenses, the plurality of lenses corresponding to the plurality of light sources,

[0338] wherein the image forming system includes a plurality of liquid crystal elements corresponding to the plurality of lenses, and

[0339] The image forming system causes the light that has passed through the plurality of lenses to be incident on the plurality of liquid crystal elements, and combines the light that has passed through the liquid crystal elements. (33)

[0341] The image display device according to one or more of (27) to (32) further includes an optical element that guides the light passing through the projection system to the user's eyeball. (34)

[0343] The image display device according to one or more of (27) to (33), further comprising a focusing optical element arranged between the light source device and the image forming system. (35)

[0345] The image display device according to one or more of (27) to (34), wherein:

[0346] The image forming system includes a digital micromirror device that receives light from the focusing optical element. (36)

[0348] The image display device according to one or more of (27) to (35), wherein:

[0349] The image forming system includes an optical deflector that receives light from the focusing optical element. (37)

[0351] An image display device according to one or more of (27) to (36), wherein the projection system includes a focusing optical element. (38)

[0353] The image display device according to one or more of (27) to (37), wherein the projection system includes a projection optical element, and wherein the focusing optical element is arranged between the image forming system and the projection optical element. (39)

[0355] The image display device according to one or more of (27) to (38), further comprising:

[0356] Optical elements that direct light passing through the projection system to the user's eye,

[0357] wherein the projection system comprises projection optics, and

[0358] The focusing optical element is arranged between the projection optical element and the optical element. (40)

[0360] A light source device, comprising:

[0361] Light source; and

[0362] an optical system comprising a lens located in the optical path of light from the light source,

[0363] wherein the lens has a numerical aperture of 0.16 or less, wherein the total radiation angle of the light source is 14° or greater, and the total radiation angle is the sum of a first radiation angle measured relative to a first direction and a second radiation angle measured relative to a second direction orthogonal to the first direction.

[0364] It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

[0365] Reference numerals

[0366] 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 light source device

[0367] 101a First LD (light source)

[0368] 101b Second LD (light source)

[0369] 101c Third LD (light source)

[0370] 102a First lens

[0371] 102b Second lens

[0372] 102c Third lens

[0373] 106a First LCD (liquid crystal element)

[0374] 106b Second LCD (liquid crystal element)

[0375] 106c Third LCD (liquid crystal element)

[0376] 201 MEMS mirror (image forming unit)

[0377] 202 DMD (image forming unit)

[0378] 301 Projection lens (projection optical system)

[0379] 302 Focusing Optical Element

[0380] 401 Eyepiece (eye optics)

[0381] 501, 502 Focusing optical element

Claims

1. A light source device, comprising: light source; as well as an optical system comprising a lens located in the optical path of light from the light source, The lens has a numerical aperture of 0.16 or less, and the light source has a total radiation angle, which is the sum of a first radiation angle measured relative to a first direction and a second radiation angle measured relative to a second direction orthogonal to the first direction. 2 . The light source device according to claim 1 , wherein the numerical aperture is 0.09 or less, and wherein the sum of the radiation angles is 14° or more. 3 . The light source device according to claim 1 , wherein the numerical aperture is 0.16 or less, and wherein the sum of the radiation angles is 23° or more. 4 . The light source device according to claim 1 , wherein the numerical aperture is 0.09 or less, and wherein the sum of the radiation angles is 23° or more. The light source device according to claim 1 , wherein the lens is a spherical lens or an aspherical lens. The light source device according to claim 1 , wherein the light source comprises a laser.

7. An image display device, comprising: A light source device, comprising: Light source; and an optical system comprising a lens located in the optical path of light from the light source, wherein the lens has a numerical aperture of 0.16 or less, and wherein the light source has a sum of radiation angles, the sum of radiation angles being a sum of a first radiation angle measured relative to a first direction and a second radiation angle measured relative to a second direction orthogonal to the first direction; an image forming system that forms an image using light from the light source device; and A projection system projects the image.

8. The image display device according to claim 7, wherein the image forming system includes an optical deflector.

9. The image display device according to claim 7, wherein the image forming system comprises a digital micromirror device.

10. The image display device according to claim 7, wherein the image forming system includes a liquid crystal element.

11. The image display device according to claim 7, further comprising: a plurality of light sources emitting light of different wavelengths; as well as a plurality of lenses, the plurality of lenses corresponding to the plurality of light sources, The optical system combines the lights from the plurality of light sources that have passed through corresponding lenses.

12. The image display device according to claim 7, further comprising: a plurality of light sources emitting light of different wavelengths; as well as a plurality of lenses, the plurality of lenses corresponding to the plurality of light sources, wherein the image forming system includes a plurality of liquid crystal elements corresponding to the plurality of lenses, and The image forming system causes the light that has passed through the plurality of lenses to be incident on the plurality of liquid crystal elements, and combines the light that has passed through the liquid crystal elements. 13 . The image display device according to claim 7 , further comprising an optical element that guides the light passing through the projection system to an eyeball of a user. 14 . The image display device according to claim 7 , further comprising a light-condensing optical element provided between the light source device and the image forming system.

15. The image display device according to claim 14, wherein The image forming system includes a digital micromirror device that receives light from the focusing optical element.

16. The image display device according to claim 14, wherein The image forming system includes an optical deflector that receives light from the focusing optical element.

17. The image display device of claim 10, wherein the projection system comprises a focusing optical element.

18. The image display device according to claim 17, wherein the projection system includes a projection optical element, and wherein the focusing optical element is disposed between the image forming system and the projection optical element.

19. The image display device according to claim 17, further comprising: Optical elements that direct light passing through the projection system to the user's eye, wherein the projection system comprises projection optics, and The focusing optical element is arranged between the projection optical element and the optical element.

20. A light source device, comprising: light source; as well as an optical system comprising a lens located in the optical path of light from the light source, wherein the lens has a numerical aperture of 0.16 or less, wherein the total radiation angle of the light source is 14° or greater, and the total radiation angle is the sum of a first radiation angle measured relative to a first direction and a second radiation angle measured relative to a second direction orthogonal to the first direction.

Images