Light-emitting device

Abstract

[Problem] To provide a light-emitting device capable of appropriately controlling light emitted from a light-emitting element. [Solution] The light-emitting device of the present disclosure includes: a substrate; a plurality of light-emitting elements provided on the first surface side of the substrate; and an optical element provided on the second surface side of the substrate, and light emitted from the plurality of light-emitting elements is incident on the optical element, wherein the optical element includes a liquid crystal layer serving as a lens.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a light-emitting device. Background Art

[0002] Surface-emitting lasers such as vertical-cavity surface-emitting lasers (VCSELs) are known as a type of semiconductor lasers. Generally, in a light-emitting device using a surface-emitting laser, a plurality of light-emitting elements are arranged in a two-dimensional array pattern on the front surface or the rear surface of a substrate.

[0003] Citation List

[0004] Patent Documents

[0005] Patent Document 1: PCT Application No. 2004-526194. Summary of the Invention

[0006] Technical Problem

[0007] In the light-emitting device as described above, for example, light emitted from a light-emitting element must be controlled by an optical element such as a lens. In this case, it is an important issue to determine which optical element to use to appropriately control the light.

[0008] In view of this, the present disclosure provides a light-emitting device capable of appropriately controlling light emitted from a light-emitting element.

[0009] Solution to the Problem

[0010] A light-emitting device according to a first aspect of the present disclosure includes: a substrate; a plurality of light-emitting elements provided on a first surface side of the substrate; and an optical element provided on a second surface side of the substrate, and light emitted from the plurality of light-emitting elements is incident on the optical element, wherein the optical element includes a liquid crystal layer configured to function as a lens. Accordingly, light can be controlled by the lens realized by the liquid crystal layer, and for example, the characteristics of the lens can be changed by driving the liquid crystal layer.

[0011] In addition, in the first aspect, the optical element may include: a first optical element on which light emitted from the plurality of light-emitting elements is incident; and a second optical element on which the light that has passed through the first optical element is incident, wherein at least one of the first optical element and the second optical element may include a liquid crystal layer configured to function as a lens. Accordingly, light from the plurality of light-emitting elements can be appropriately controlled by the first optical element and the second optical element.

[0012] In addition, in the first aspect, the first optical element may include a liquid crystal layer configured to function as a plurality of first lenses, light emitted from a plurality of light-emitting elements is incident on the plurality of first lenses, and the second optical element may include a liquid crystal layer configured to function as a second lens, light that has passed through the plurality of first lenses is incident on the second lens. Thus, for example, light from the plurality of light-emitting elements can be appropriately shaped by the first lens and the second lens.

[0013] In addition, in the first aspect, the first optical element may include a liquid crystal layer configured to function as a plurality of first lenses, light emitted from a plurality of light-emitting elements is incident on the plurality of first lenses, and the second optical element may include a second lens that is not a liquid crystal, light that has passed through the plurality of first lenses is incident on the second lens. Thus, for example, light from the plurality of light-emitting elements can be appropriately shaped by the first lens and the second lens.

[0014] In addition, in the first aspect, the first optical element may include a plurality of first lenses that are not liquid crystals, light emitted from a plurality of light-emitting elements is incident on the plurality of first lenses, and the second optical element may include a liquid crystal layer configured to function as a second lens, light that has passed through the plurality of first lenses is incident on the second lens. Thus, for example, light from the plurality of light-emitting elements can be appropriately shaped by the first lens and the second lens.

[0015] In addition, in the first aspect, the optical element may include a first electrode provided on one side of the substrate of the liquid crystal layer and a second electrode provided on the side of the liquid crystal layer opposite to the substrate. Thus, the liquid crystal layer can be driven by the first electrode and the second electrode.

[0016] In addition, in the first aspect, the first electrode or the second electrode may include a plurality of electrodes having an annular shape. Thus, for example, the liquid crystal layer can be easily used as a lens.

[0017] In addition, in the first aspect, the first electrode or the second electrode may include a plurality of electrodes arranged in a square lattice shape. Thus, for example, the liquid crystal layer can be easily used as a lens.

[0018] In addition, in the first aspect, the liquid crystal layer may be sandwiched between a first substrate and a second substrate, and a lens may be provided on the surface of at least one of the first substrate and the second substrate. Thus, light from the plurality of light-emitting elements can be further shaped by the lens.

[0019] In addition, in the first aspect, the liquid crystal layer may be divided into a plurality of regions and sealed to correspond one-to-one with the plurality of light-emitting elements. Thus, for example, the liquid crystal layer can be more easily controlled for each individual light-emitting element.

[0020] In addition, in the first aspect, the liquid crystal layer can be divided into a plurality of regions and sealed, and the number of the plurality of regions is less than the number of the plurality of light-emitting elements. Thus, for example, light from two or more light-emitting elements can be controlled by a single large lens in the liquid crystal layer.

[0021] In addition, in the first aspect, the substrate can be a semiconductor substrate containing gallium (Ga) and arsenic (As). Thus, a substrate suitable for a light-emitting device can be provided.

[0022] In addition, in the first aspect, light emitted from the plurality of light-emitting elements can be transmitted from the first surface to the second surface inside the substrate and can be incident on the optical element. Thus, a structure in which light is transmitted through the substrate and emitted from the light-emitting device can be achieved.

[0023] In addition, in the first aspect, the first surface of the substrate can be the front surface of the substrate, and the second surface of the substrate can be the back surface of the substrate. Thus, a backlight type light-emitting device can be provided.

[0024] Furthermore, the light-emitting device according to the first aspect can further include a driving device, which is disposed on the first surface side of the substrate via the plurality of light-emitting elements and is configured to drive the plurality of light-emitting elements. Thus, for example, the substrate provided with the light-emitting elements can be loaded on the driving device.

[0025] In addition, in the first aspect, the driving device can be configured to drive the plurality of light-emitting elements on an individual basis. Thus, light emitted from the plurality of light-emitting elements can be controlled more precisely.

[0026] Furthermore, in the first aspect, the driving device can be further configured to drive the liquid crystal layer. Thus, the driving device for the light-emitting elements can also be used for the liquid crystal layer.

[0027] In addition, in the first aspect, the second optical element can be configured to receive light that has passed through the first optical element and is reflected by the mirror, reflect light that has passed through the first optical element, or receive light that has passed through the first optical element and passed through the mirror. Thus, the control of the light between the first optical element and the second optical element and the positional relationship between the first optical element and the second optical element can be freely designed.

[0028] The light-emitting device according to the second aspect of the present disclosure includes: a substrate; a light-emitting element disposed on the first surface side of the substrate; and an optical element disposed on the second surface side of the substrate, and light emitted from the light-emitting element is incident on the optical element, wherein the optical element includes a liquid crystal layer configured to function as a diffraction grating. Thus, light can be controlled by the diffraction grating realized by the liquid crystal layer, and for example, the characteristics of the diffraction grating can be changed by driving the liquid crystal layer.

[0029] In addition, in a second aspect, the optical element may include a first electrode provided on one side of the substrate of the liquid crystal layer and a second electrode provided on the side of the liquid crystal layer opposite to the substrate. Thus, the liquid crystal layer can be driven by the first electrode and the second electrode.

[0030] In addition, in a second aspect, the first electrode or the second electrode may include a plurality of linear electrodes arranged parallel to each other. Thus, for example, the liquid crystal layer can be easily used as a diffraction grating.

[0031] In addition, in a second aspect, the liquid crystal layer may have a first surface on one side of the substrate, a second surface on the side opposite to the substrate, and a third surface between the first surface and the second surface, wherein the optical element may include a first electrode and a second electrode, and the first electrode and the second electrode are arranged to sandwich the liquid crystal layer on the third surface of the liquid crystal layer. Thus, the liquid crystal layer can be driven by the first electrode and the second electrode. In addition, the first electrode and the second electrode may be arranged, for example, at positions away from the optical path of light from the light-emitting element.

[0032] A light-emitting device according to a third aspect of the present disclosure includes: a substrate; a light-emitting element provided on the first surface side of the substrate; and an optical element provided on the second surface side of the substrate, and light emitted from the light-emitting element is incident on the optical element, wherein the optical element includes a liquid crystal layer configured to be used as a light valve. Thus, light can be controlled by the light valve realized by the liquid crystal layer, and for example, the characteristics of the light valve can be changed by driving the liquid crystal layer.

[0033] In addition, in a third aspect, while continuously emitting light from the light-emitting element, the light-emitting device controls the on / off of the light emitted from the light-emitting device by controlling the on / off of the light valve. Thus, the on / off of light can be controlled by driving the liquid crystal layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a block diagram showing the configuration of a distance measuring device according to the first embodiment.

[0035] Figure 2 is a cross-sectional view showing an example of the structure of a distance measuring device according to the first embodiment.

[0036] Figure 3 is a view showing Figure 2 a cross-sectional view of the structure of the distance measuring device shown at B in

[0037] Figure 4 is a cross-sectional view showing the structure of a light-emitting device according to the first embodiment.

[0038] Figure 5 is a view showing Figure 4 a plan view of an example of the structure of the lower optical element shown in

[0039] Figure 6 is a plan view showing an example of the structure of the lower electrode shown. Figure 4 The lower electrode shown.

[0040] Figure 7 is a cross-sectional view showing the structure of a light-emitting device modified according to the first embodiment.

[0041] Figure 8 is a cross-sectional view showing the structure of a light-emitting device modified according to another modification of the first embodiment.

[0042] Figure 9 is a cross-sectional view showing the structure of a light-emitting device modified according to another modification of the first embodiment.

[0043] Figure 10 is a cross-sectional view showing the structure of a light-emitting device modified according to another modification of the first embodiment.

[0044] Figure 11 is a plan view showing an example of the structure of the lower optical element shown. Figure 10 The lower optical element shown.

[0045] Figure 12 is a cross-sectional view showing the structure of a light-emitting device modified according to another modification of the first embodiment.

[0046] Figure 13 is a plan view showing an example of the structure of the lower optical element shown. Figure 12 The lower optical element shown.

[0047] Figure 14 is a plan view showing various examples of the structure of the lower optical element shown. Figure 4 The lower optical element shown.

[0048] Figure 15 is a cross-sectional view showing the structure of a light-emitting device according to the second embodiment.

[0049] Figure 16 is a plan view showing an example of the structure of the lower electrode shown. Figure 15 The lower electrode shown.

[0050] Figure 17 is a plan view showing the structure of an upper optical element modified according to the second embodiment.

[0051] Figure 18 is a cross-sectional view showing the structure of a light-emitting device according to the third embodiment.

[0052] Figure 19 is a timing chart showing an example of the operation of a light-emitting device according to the third embodiment.

[0053] Figure 20 This is a cross-sectional view showing the structure of a light-emitting device according to various modifications of the first embodiment. Detailed Embodiment

[0054] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0055] (First Embodiment)

[0056] Figure 1 This is a block diagram showing the configuration of a distance measurement device according to the first embodiment.

[0057] Figure 1 The shown distance measurement device includes a light-emitting device 1, an imaging device 2, and a control device 3. Figure 1 The shown distance measurement device irradiates an object with light emitted from the light-emitting device 1, images the object by receiving the light reflected by the object with the imaging device 2, and measures (calculates) the distance to the object using the control device 3 with the image signal output from the imaging device 2. The light-emitting device 1 serves as a light source used when the imaging device 2 images the object.

[0058] The light-emitting device 1 includes a light-emitting unit 11, a drive circuit 12, a power supply circuit 13, and a light-emitting side optical system 14. The imaging device 2 includes an image sensor 21, an image processing unit 22, and an imaging side optical system 23. The control device 3 includes a distance measurement unit 31.

[0059] The light-emitting unit 11 emits laser light for irradiating the object. As will be described later, the light-emitting unit 11 according to the present embodiment includes a plurality of light-emitting elements arranged in a two-dimensional array pattern and each light-emitting element has a VCSEL structure. The object is irradiated with the light emitted from the light-emitting element. In addition, the light-emitting unit 11 according to the present embodiment is provided inside a chip called a laser diode (LD) chip 41.

[0060] The drive circuit 12 is a circuit for driving the light-emitting unit 11. The power supply circuit 13 is a circuit for generating the power supply voltage of the drive circuit 12. For example, the distance measurement device according to the present embodiment generates the power supply voltage by the power supply circuit 13 based on the input voltage supplied from a battery inside the distance measurement device and drives the light-emitting unit 11 using the power supply voltage by the drive circuit 12. In addition, the drive circuit 12 according to the present embodiment is provided inside a substrate called a laser diode driver (LDD) substrate 42.

[0061] The light-emitting side optical system 14 includes various optical elements and irradiates the object with the light from the light-emitting unit 11 via the optical elements. In a similar manner, the imaging side optical system 23 includes various optical elements and receives the light from the object via the optical elements.

[0062] The image sensor 21 receives light from an object via the imaging-side optical system 23 and converts the light into an electrical signal by photoelectric conversion. For example, the image sensor 21 is a charge-coupled device (CCD) sensor or a complementary metal-oxide semiconductor (CMOS) sensor. The image sensor 21 according to the present embodiment converts the above electrical signal from an analog signal into a digital signal by analog-to-digital (A / D) conversion, and outputs an image signal as a digital signal to the image processing unit 22. In addition, the image sensor 21 according to the present embodiment outputs a frame synchronization signal to the drive circuit 12, and based on the frame synchronization signal, the drive circuit 12 causes the light-emitting unit 11 to emit light at a timing according to the frame period in the image sensor 21.

[0063] The image processing unit 22 performs various types of image processing on the image signal output from the image sensor 21. For example, the image processing unit 22 includes an image processing processor such as a digital signal processor (DSP).

[0064] The control device 3 controls Figure 1 various operations of the ranging device shown, such as the light-emitting operation of the light-emitting device 1 and the imaging operation of the imaging device 2. For example, the control device 3 includes a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), etc.

[0065] The ranging unit 31 measures the distance to the object based on the image signal output from the image sensor 21 and that has been subjected to image processing by the image processing unit 22. As a ranging method, for example, the ranging unit 31 employs a structured light (STL) method or a time-of-flight (ToF) method. The ranging unit 31 can further specify the three-dimensional shape of the object by measuring the distance between the ranging device and the object for each part of the object based on the above image signal.

[0066] Figure 2 is a cross-sectional view showing an example of the structure of the ranging device according to the first embodiment.

[0067] Figure 2 A in shows a first example of the structure of the ranging device according to the first embodiment. The ranging device according to the example includes the above LD chip 41 and LDD substrate 42, mounting substrate 43, heat dissipation substrate 44, correction lens holding unit 45, one or more correction lenses 46, and wiring 47.

[0068] Figure 2In A, an x-axis, a Y-axis, and a z-axis perpendicular to each other are shown. The x-direction and the Y-direction correspond to the lateral direction (horizontal direction), and the Z-direction corresponds to the longitudinal direction (vertical direction). Further, the +Z direction corresponds to the upward direction, and the -Z direction corresponds to the downward direction. The -Z direction may or may not strictly coincide with the direction of gravity.

[0069] The LD chip 41 is disposed on the mounting substrate 43 via the heat dissipation substrate 44, and the LDD substrate 42 is also disposed on the mounting substrate 43. The mounting substrate 43 is, for example, a printed circuit board. Figure 1 The image sensor 21 and the image processing unit 22 shown are also disposed on the mounting substrate 43 according to the present embodiment. The heat dissipation substrate 44 is, for example, a ceramic substrate such as an aluminum nitride (AlN) substrate.

[0070] The correction lens holding unit 45 is disposed on the heat dissipation substrate 44 so as to surround the LD chip 41, and holds one or more correction lenses 46 above the LD chip 41. The correction lens 46 is included in the above-described light emitting side optical system 14 ( Figure 1 )). The light emitted from the light emitting unit 11 ( Figure 1 ) inside the LD chip 41 is corrected by the correction lens 46, and then, the object ( Figure 1 ) is irradiated with the corrected light. For example, Figure 2 in A, two correction lenses 46 held by the correction lens holding unit 45 are shown.

[0071] The wiring 47 is provided on the front surface and the rear surface of the mounting substrate 43, inside the mounting substrate 43, etc., and electrically connects the LD chip 41 and the LDD substrate 42 to each other. The wiring 47 is, for example, printed wiring provided on the front surface and the rear surface of the mounting substrate 43 or via wiring penetrating the mounting substrate 43. The wiring 47 according to the present embodiment further passes through the inside or near the heat dissipation substrate 44.

[0072] Figure 2 In B, a second example of the structure of the distance measuring device according to the present embodiment is shown. Although the distance measuring device according to this example includes the same components as the distance measuring device according to the first example, the distance measuring device according to the second example includes bumps 48 instead of the wiring 47.

[0073] In Figure 2 B, the LDD substrate 42 is disposed on the heat dissipation substrate 44, and the LD chip 41 is disposed on the LDD substrate 42. By disposing the LD chip 41 on the LDD substrate 42 in this way, the mounting substrate 43 can be miniaturized compared with the first example. In Figure 2In B, the LD chip 41 is disposed on the LDD substrate 42 via bumps 48, and the LD chip 41 is electrically connected to the LDD substrate 42 through the bumps 48.

[0074] Hereinafter, on the assumption that the distance measuring device has a structure of the second example shown in B of Figure 2 , the distance measuring device according to the present embodiment will be described. However, in addition to explaining the structure specific to the second example, the following description also applies to the distance measuring device having a structure according to the first example.

[0075] Figure 3 is a sectional view showing Figure 2 the structure of the distance measuring device shown in B of

[0076] Figure 3 A cross section of the LD chip 41 and the LDD substrate 42 inside the light emitting device 1 is shown. As Figure 3 shown, the LD chip 41 includes a substrate 51, a laminated film 52, a plurality of light emitting elements 53, a plurality of anode electrodes 54, and a plurality of cathode electrodes 55. In addition, the LDD substrate 42 includes a substrate 61 and a plurality of connection pads 62. It should be noted that in Figure 3 , illustrations of the lower optical element 71 and the upper optical element 72 (described later) are omitted (refer to Figure 4 ).

[0077] The substrate 51 is a semiconductor substrate such as a gallium arsenide (GaAs) substrate. Figure 3 The front surface S1 of the substrate 51 facing the -Z direction and the back surface S2 of the substrate 51 facing the +Z direction are shown. The front surface S1 is an example of the first surface according to the present disclosure. The back surface S2 is an example of the second surface according to the present disclosure.

[0078] The laminated film 52 includes a plurality of layers laminated on the front surface S1 of the substrate 51. Examples of the layers include an n-type semiconductor layer, an active layer, a p-type semiconductor layer, a light reflection layer, and an insulating layer having a light emitting window. The laminated film 52 includes a plurality of mesa portions M protruding in the -Z direction. A part of the mesa portion M constitutes a plurality of light emitting elements 53.

[0079] The plurality of light emitting elements 53 are provided on the front surface S1 side of the substrate 52 as a part of the laminated film 52. Each light emitting element 53 according to the present embodiment has a VCSEL structure and emits light in the +z direction. As Figure 3 shown, the light emitted from each light emitting element 53 is transmitted from the front surface S1 to the back surface S2 inside the substrate 51, and enters the above-described correction lens 46 from the substrate 51 ( Figure 2 ). In this way, the LD chip 41 according to the present embodiment is configured as a back-illuminated VCSEL chip.

[0080] The anode electrode 54 is formed on the lower surface of the light-emitting element 53. The cathode electrode 55 is formed on the lower surface of the mesa portion M except for the light-emitting element 53 and extends to the lower surface of the laminated film 52 between the mesa portions M. When current flows between the anode 54 and the corresponding cathode electrode 55, each light-emitting element 53 emits light.

[0081] As described above, the LD chip 41 is disposed on the LDD substrate 42 via the bumps 48, and the LD chip 41 is electrically connected to the LDD substrate 42 through the bumps 48. Specifically, the connection pads 62 are formed on the substrate 61 included in the LDD substrate 42, and the mesa portion M is disposed on the connection pads 62 via the bumps 48. Each mesa portion M is disposed on the bump 48 via the anode electrode 54 or the cathode electrode 55. The substrate 61 is a semiconductor substrate such as a silicon (Si) substrate.

[0082] The LDD substrate 42 includes a drive circuit 12 for driving the light-emitting unit 11 ( Figure 1 ). Figure 3 A plurality of switches SW included in the drive circuit 12 are schematically shown. Each switch SW is electrically connected to the corresponding light-emitting element 53 via the bump 48. The drive circuit 12 according to the present embodiment can control the switch SW (on / off) on an individual basis. Therefore, the drive circuit 12 can drive a plurality of light-emitting elements 53 based on each light-emitting element 53. Therefore, the light emitted from the light-emitting unit 11 can be precisely controlled, such as only causing the light-emitting elements 53 required for distance measurement to emit light. This individual control of the light-emitting elements 53 is achieved by disposing the LDD substrate 42 below the LD chip 41 so that each light-emitting element 53 is more easily electrically connected to the switch SW corresponding to the light-emitting element 53. The LDD substrate 42 is an example of a drive device according to the present disclosure.

[0083] Figure 4 is a cross-sectional view showing the structure of the light-emitting device 1 according to the first embodiment.

[0084] Figure 4 A cross-section of the LD chip 41 and the LDD substrate 42 inside the light-emitting device 1 is shown. As described above, the LD chip 41 includes a substrate 51, a laminated film 52, a plurality of light-emitting elements 53, a plurality of anode electrodes 54, and a plurality of cathode electrodes 55, and the LDD substrate 42 includes a substrate 61 and a plurality of connection pads 62. It should be noted that Figure 4 the illustrations of the anode electrode 54, the cathode electrode 55, and the connection pad 62 are omitted.

[0085] The light-emitting device 1 according to the present embodiment includes a plurality of light-emitting elements 53 on the front surface S1 side of the substrate 51, and includes a lower optical element 71, an upper optical element 72, and three substrates 73, 74, and 75 on the rear surface S2 side of the substrate 51. The light-emitting device 1 according to the present embodiment further includes a plurality of wirings 76, a plurality of liquid crystal driving units 77, and a liquid crystal driving element 78. The lower optical element 71 and the upper optical element 72 are examples of the optical elements according to the present disclosure, and are examples of the first optical element and the second optical element according to the present disclosure, respectively.

[0086] The lower optical element 71 is disposed between the substrates 73 and 74 and includes a plurality of lower electrodes 81, upper electrodes 82, a lower alignment film 83, an upper alignment film 84, a liquid crystal layer 85, a plurality of spacer materials 86, and a liquid crystal sealant 87. The lower electrode 81 and the upper electrode 82 are examples of the first electrode and the second electrode according to the present disclosure, respectively.

[0087] The upper optical element 72 is disposed between the substrates 74 and 75 and includes a lower electrode 91, an upper electrode 92, a lower alignment film 93, an upper alignment film 94, a liquid crystal layer 95, a plurality of spacer materials 96, and a liquid crystal sealant 97. The lower electrode 91 and the upper electrode 92 are examples of the first electrode and the second electrode according to the present disclosure, respectively.

[0088] The substrates 73, 74, and 75 are sequentially laminated on the substrate 51 via the lower optical element 71 and the upper optical element 72. The substrates 73, 74, and 75 are transparent substrates such as glass substrates or quartz substrates, for example. The substrates 73 and 74 are arranged to sandwich the lower optical element 71 (specifically, the liquid crystal layer 85), and the substrates 74 and 75 are arranged to sandwich the upper optical element 72 (specifically, the liquid crystal layer 95).

[0089] The lower electrode 81 is disposed on the upper surface of the substrate 73, and the upper electrode 82 is disposed on the lower surface of the substrate 74. The lower electrode 81 and the upper electrode 82 are transparent electrodes such as indium tin oxide (ITO) electrodes, for example. The lower electrode 81 is disposed on the substrate 51 side of the liquid crystal layer 85, and the upper electrode 82 is disposed on the side opposite to the substrate 51 of the liquid crystal layer 85. The lower electrode 81 and the upper electrode 82 are used to drive the liquid crystal layer 85, and more specifically, to control the orientation of the liquid crystal molecules inside the liquid crystal layer 85. The lower electrode 81 according to the present embodiment corresponds to the light-emitting element 53 one by one, and each lower electrode 81 is disposed in the +z direction of the corresponding light-emitting element 53. On the other hand, the upper electrode 82 according to the present embodiment is disposed in the +z direction of the plurality of light-emitting elements 53 and is configured as a common electrode corresponding to the plurality of light-emitting elements 53.

[0090] The lower alignment film 83 is provided on the upper surface of the substrate 73 via the lower electrode 81, and the upper alignment film 84 is provided on the lower surface of the substrate 74 via the upper electrode 82. The lower alignment film 83 and the upper alignment film 84 are, for example, a transparent inorganic film such as a silicon oxide film or a transparent organic film such as a polyimide film. The lower alignment film 83 and the upper alignment film 84 according to the present embodiment have a plurality of grooves for aligning liquid crystal molecules inside the liquid crystal layer 85.

[0091] The liquid crystal layer 85 is provided between the lower alignment film 83 and the upper alignment film 84. Figure 4 A plurality of lenses L1 realized inside the liquid crystal layer 85 are shown. The liquid crystal layer 85 according to the present embodiment can be used as the lens L1 by being driven by the lower electrode 81 and the upper electrode 82. The lens L1 is an example of the first lens according to the present disclosure. The lens L1 according to the present embodiment corresponds one-to-one with the light-emitting element 53, and each lens L1 is generated in the +z direction of the corresponding light-emitting element 53. Although the lens L1 is Figure 4 a concave lens in, the lens L1 can alternatively be a convex lens.

[0092] The spacer material 86 is provided between the substrates 73 and 74 to maintain a constant gap between the substrates 73 and 74. The spacer material 86 is, for example, silica particles. The spacer material 86 according to the present embodiment is embedded in the liquid crystal sealant 87.

[0093] The liquid crystal sealant 87 is provided between the substrates 73 and 74 to seal the liquid crystal layer 85 between the substrates 73 and 74. The material of the liquid crystal sealant 87 is, for example, resin. The liquid crystal sealant 87 according to the present embodiment is provided so as to surround the liquid crystal layer 85 in a ring shape.

[0094] The lower electrode 91 is provided on the upper surface of the substrate 74, and the upper electrode 92 is provided on the lower surface of the substrate 75. The lower electrode 91 and the upper electrode 92 are, for example, transparent electrodes such as ITO electrodes. The lower electrode 91 is provided on one side of the substrate 51 of the liquid crystal layer 95, and the upper electrode 92 is provided on the side opposite to the substrate 51 of the liquid crystal layer 95. The lower electrode 91 and the upper electrode 92 are used to drive the liquid crystal layer 95, and more specifically, to control the orientation of liquid crystal molecules inside the liquid crystal layer 95. The lower electrode 91 according to the present embodiment is arranged in the +z direction of the plurality of light-emitting elements 53 and is configured as a common electrode corresponding to the plurality of light-emitting elements 53. In a similar manner, the upper electrode 92 according to the present embodiment is arranged in the +z direction of the plurality of light-emitting elements 53 and is configured as a common electrode corresponding to the plurality of light-emitting elements 53.

[0095] The lower alignment film 93 is disposed on the upper surface of the substrate 74 via the lower electrode 91, and the upper alignment film 94 is disposed on the lower surface of the substrate 75 via the upper electrode 92. The lower alignment film 93 and the upper alignment film 94 are, for example, transparent inorganic films such as silicon oxide films or transparent organic films such as polyimide films. The lower alignment film 93 and the upper alignment film 94 according to the present embodiment have a plurality of grooves for aligning liquid crystal molecules inside the liquid crystal layer 95.

[0096] The liquid crystal layer 95 is disposed between the lower alignment film 93 and the upper alignment film 94. Figure 4 The lens L2 realized inside the liquid crystal layer 95 is shown. The liquid crystal layer 95 according to the present embodiment can be used as the lens L2 by being driven by the lower electrode 91 and the upper electrode 92. The lens L2 is an example of the second lens according to the present disclosure. The lens L2 according to the present embodiment is a common lens corresponding to the plurality of light-emitting elements 53, and the lens L2 is generated in the +z direction of the plurality of light-emitting elements 53. Although the lens L2 is Figure 4 a convex lens in, the lens L2 can alternatively be a concave lens.

[0097] The spacer material 96 is disposed between the substrates 74 and 75 to maintain a constant gap between the substrates 74 and 75. The spacer material 96 is, for example, silica particles. The spacer material 96 according to the present embodiment is embedded in the liquid crystal sealant 97.

[0098] The liquid crystal sealant 97 is disposed between the substrates 74 and 75 to seal the liquid crystal layer 95 between the substrates 74 and 75. The material of the liquid crystal sealant 97 is, for example, resin. The liquid crystal sealant 97 according to the present embodiment is provided to surround the liquid crystal layer 95 in a ring shape.

[0099] The wiring 76 is disposed inside the substrate 73 and the like, and electrically connects the lower electrode 81 and the liquid crystal driving element 78. Each wiring 76 according to the present embodiment electrically connects one lower electrode 81 to the liquid crystal driving element 78 corresponding to the lower electrode 81.

[0100] The liquid crystal driving unit 77 is a circuit for driving the liquid crystal layer 85 by applying a voltage to the lower electrode 81. The liquid crystal driving unit 77 according to the present embodiment is disposed inside the substrate 61 and forms a part of the LDD substrate 42. Therefore, the LDD substrate 42 can be used not only for driving the light-emitting elements 53 but also for driving the liquid crystal layer 85. The liquid crystal driving units 77 according to the present embodiment correspond to the lower electrodes 81 one by one, and each liquid crystal driving unit 77 can generate one lens L1 having the corresponding lower electrode 81.

[0101] The liquid crystal driving element 78 is an element for driving the liquid crystal layer 85 or the liquid crystal layer 95 by applying a voltage to the upper electrode 82, the lower electrode 91, or the upper electrode 92. The liquid crystal driving element 78 according to the present embodiment is provided on the lower surface of the substrate 73. For example, the liquid crystal driving element 78 can generate the lens L2 by applying a driving voltage to the lower electrode 91 or the upper electrode 92.

[0102] The light emitted from the plurality of light-emitting elements 53 is transmitted from the front surface S1 to the rear surface S2 inside the substrate 51 and enters the plurality of lenses L1 inside the liquid crystal layer 85. In the present embodiment, the light emitted from each light-emitting element 53 is incident on the corresponding lens L1. The light passing through the lens L1 is incident on the lens L2 inside the liquid crystal layer 95, and the light passing through the lens L2 is incident on the correction lens 46 ( Figure 2 B in). In the present embodiment, the lenses L1 and L2 diffuse and focus the light from the light-emitting element 53, and the correction lens 46 collimates the light from the lenses L1 and L2 to generate parallel light. The light passing through the correction lens 46 is emitted toward the object ( Figure 1 ).

[0103] Figure 4 Further shown are a plurality of light-transmitting regions R that transmit the light from each light-emitting element 53 and a central axis C located at the center of each light-transmitting region R. In Figure 4 , the front surface S1 of the substrate 51 is perpendicular to the z direction, and each central axis C is parallel to the z direction. The lower optical element 71, the upper optical element 72, and the substrates 73, 74, and 75 according to the present embodiment can be configured such that light can pass through portions other than the light-transmitting regions R, or can be configured to include light-shielding members in portions other than the light-transmitting regions R.

[0104] According to the present embodiment, for example, by disposing the lenses L1 and L2 between the light-emitting element 53 and the correction lens 46, the aberration of the correction lens 46 can be reduced. This is because, by diffusing the light from the light-emitting element 53 with the lens L1 and focusing the light from the lens L1 with the lens L2, the light from the light-emitting element 53 can be easily collimated by the correction lens 46. Therefore, blurring or distortion at the end of the image can be suppressed, and the high-resolution imaging device 2 ( Figure 1 ) can be realized. It should be noted that such an effect can be produced even when the lens L1 is a lens other than a concave lens, and such an effect can be produced even when the lens L2 is a lens other than a convex lens.

[0105] In the present embodiment, the lenses L1 and L2 that produce this effect are realized by the liquid crystal layers 85 and 95. Therefore, the characteristics of the lenses L1 and L2 can be changed by driving the liquid crystal layers 85 and 95 (optically variable lenses). For example, the radius, depth, curvature, and position of the lenses L1 and L2, as well as the distance between the lenses L1, can be adjusted to values suitable for collimation by the correction lens 46. In addition, by performing various adjustments to the characteristics of the lenses L1 and L2, the number of optical elements of the light-emitting device 1 can be reduced, and miniaturization and weight reduction of the light-emitting device 1 can be achieved. In this way, according to the present embodiment, the light emitted from the light-emitting element 53 can be appropriately controlled by the lenses L1 and L2 inside the liquid crystal layers 85 and 95.

[0106] Although the light-emitting device 1 according to the present embodiment includes two liquid crystal layers 85 and 95, alternatively, the light-emitting device 1 according to the present embodiment may include only one of the liquid crystal layers 85 and 95. For example, when the aberration of the correction lens 46 can be sufficiently reduced by adjusting the light from the light-emitting element 53 using only the lens L1, the light-emitting device 1 may include only the liquid crystal layer 85.

[0107] In addition, the lens L2 according to the present embodiment can be used as a lens instead of the correction lens 46. In this case, the correction lens 46 shown in B in Figure 2 is not required, or the number of correction lenses 46 shown in B in Figure 2 is reduced.

[0108] In addition, although the lower electrodes 81 and 91 and the upper electrodes 82 and 92 are transparent electrodes such as ITO electrodes in the present embodiment, the lower electrodes 81 and 91 and the upper electrodes 82 and 92 may be electrodes that allow only light of a predetermined wavelength to pass through. For example, when a given light-emitting element 53 is provided to emit blue light, each electrode for the light-emitting element 53 may be configured to allow only blue light to pass through. In addition, when a given light-emitting element 53 is provided to emit infrared light, each electrode for the light-emitting element 53 may be configured to allow only infrared light to pass through. This description also applies to the lower alignment films 83 and 93, the upper alignment films 84 and 94, and the substrates 73, 74, and 75. For example, the lower electrodes 81 and 91 and the upper electrodes 82 and 92 may be semiconductor layers or metal layers, and specifically, may be thin films made of aluminum (Al) or titanium (Ti).

[0109] In addition, in the present embodiment, although the lower electrode 81 is configured as a separate electrode provided for the light-emitting element 53, and the upper electrode 82, the lower electrode 91, and the upper electrode 92 are configured as common electrodes provided for a plurality of light-emitting elements 53, other configurations may also be adopted. For example, the lower electrode 81 may be configured as a common electrode, and the upper electrode 82 may be configured as a separate electrode.

[0110] Figure 5 is a plan view showing Figure 4 an example of the structure of the lower optical element 71 shown.

[0111] Figure 5 shows the positional relationship among the lower electrode 81, the liquid crystal layer 85, and the liquid crystal seal 87 of the lower optical element 71. Figure 5 Also shown are the positions of the light-emitting elements 53 and the position of the light transmission region R.

[0112] In Figure 5 the region shown, the liquid crystal layer 85 for two light-emitting elements 53 is surrounded by the liquid crystal seal 87 in a ring shape. Hereinafter, this region will be referred to as the "unit seal region". The lower optical element 71 according to the present embodiment includes a plurality of such unit seal regions. For example, the lower optical element 71 according to the present embodiment includes four liquid crystal layers 85 for eight light-emitting elements 53 inside four unit seal regions. In this way, the liquid crystal layer 85 according to the present embodiment is divided into a plurality of unit seal regions and sealed, and the number of the plurality of unit seal regions is less than the number of the light-emitting elements 53. As will be described later, the number of the light-emitting elements 53 in each unit seal region may be a number other than two. The same description applies to the upper optical element 72.

[0113] Figure 6 is a plan view showing Figure 4 an example of the structure of the lower electrode 81 shown. Each lower electrode 81 according to the present embodiment can be configured as in these examples.

[0114] In Figure 6 the example shown in A, the lower electrode 81 includes a plurality of electrodes 81a having an annular shape. These electrodes 81a are arranged concentrically around the above-mentioned central axis C. For example, when implementing the lens L1 having a shape symmetric with respect to the central axis C, such a lower electrode 81 is useful. Further, by providing resistors between the electrodes 81a, light having a gradient can also be output from the lens L1. Ideally, the electrodes 81a can be driven independently of each other. It should be noted that the shape of each electrode 81a may be a shape other than a square (such as a circle or an ellipse). Further, the spacing between the electrodes 81a may be different for each pair of adjacent electrodes 81a, and for example, the farther away from the central axis C, the smaller the spacing.

[0115] In Figure 6 the example shown in B, the lower electrode 81 includes a plurality of electrodes 81b arranged in a square lattice shape (two-dimensional array pattern). For example, when finely controlling the shape of the lens L1, such a lower electrode 81 is useful. Ideally, the electrodes 81b can be driven independently of each other.

[0116] When electrodes other than the lower electrode 81 are formed as individual electrodes, the electrodes may be configured as in these examples.

[0117] Hereinafter, reference will be made to Figures 7 to 14 the light-emitting device 1 according to various modifications of the present embodiment.

[0118] Figure 7 is a cross-sectional view showing the structure of the light-emitting device 1 according to a modification of the first embodiment.

[0119] According to this modification, the upper optical element 72 includes a lens L2 that is not a liquid crystal, instead of the liquid crystal layer 95 that serves as the lens L2. The lens L2 according to this modification is a convex lens formed on the surface of the lens film 98. The lens film 98 is, for example, a silicon oxide film. The lens L2 according to this modification may be a lens other than a convex lens (for example, a concave lens).

[0120] For example, when the lens L2 can be easily formed by processing the lens film 98, such a structure can be adopted.

[0121] Figure 8 is a cross-sectional view showing the structure of the light-emitting device 1 according to another modification of the first embodiment.

[0122] According to this modification, the lower optical element 71 includes a plurality of lenses L1 that are not liquid crystals, instead of the liquid crystal layer 85 that serves as the plurality of lenses L1. The lens L1 according to this modification is a convex lens or a concave lens formed at the interface between a first lens film 88a and a second lens film 88b inside the lens film 88. The first lens film 88a and the second lens film 88b are, for example, transparent films formed of different materials from each other. Figure 8 The two lenses L1 shown may both be convex lenses, may both be concave lenses, or may be other lenses.

[0123] For example, when the lens L1 can be easily formed by processing the lens film 88, such a structure can be adopted.

[0124] Figure 9 is a cross-sectional view showing the structure of the light-emitting device 1 according to another modification of the first embodiment.

[0125] According to this modification, the lower optical element 71 has the same structure as Figure 8 the lower optical element 71 shown. On the other hand, the upper optical element 72 according to this modification is sandwiched between a substrate 74 having convex portions 74a and concave portions 74b on its upper surface and a substrate 75 having convex portions 75a and concave portions 75b on its lower surface. The substrate 74 is an example of the first substrate according to the present disclosure, and the substrate 75 is an example of the second substrate according to the present disclosure.

[0126] The convex portions 74a and 75a are arranged in the +z direction of the left light-emitting element 53. The convex portion 74a serves as a convex lens of a stage before the lens L2, and the convex portion 75a serves as a concave lens of a stage after the lens L2. The gap between the convex portions 74a and 75a is narrower than the gaps of other portions between the substrates 74 and 75.

[0127] The concave portions 74b and 75b are arranged in the +z direction of the right light-emitting element 53. The concave portion 74b serves as a concave lens of a stage before the lens L2, and the concave portion 75b serves as a convex lens of a stage after the lens L2. The gap between the concave portions 74b and 75b is wider than the gaps of other portions between the substrates 74 and 75.

[0128] According to this modification, the light output to the correction lens 46 can be adjusted not only by the lenses L1 and L2, but also by the lenses formed by the convex portions 74a and 75a and the concave portions 74b and 75b. Therefore, for example, the aberration of the correction lens 46 can be further reduced.

[0129] It should be noted that the lower optical element 71 according to this modification may have the same structure as the Figure 4 lower optical element 71 shown. In addition, although both of the substrates 74 and 75 have lenses in this modification, only one substrate may have a lens.

[0130] Figure 10 is a cross-sectional view showing the structure of the light-emitting device 1 according to another modification of the first embodiment.

[0131] In the lower optical element 71 according to this modification, the gap material 86 and the liquid crystal sealant 87 are also provided between the light-transmitting regions R. Accordingly, the liquid crystal layer 85 is divided for each light-emitting element 53 and sealed so as to correspond to the light-emitting element 53 one by one.

[0132] In a similar manner, in the upper optical element 72 according to this modification, the gap material 96 and the liquid crystal sealant 97 are also provided between the light-transmitting regions R. Accordingly, the liquid crystal layer 95 is divided for each light-emitting element 53 and sealed so as to correspond to the light-emitting element 53 one by one.

[0133] According to the lower optical element 71 such as Figure 10 shown, for example, it is easier to control the liquid crystal layer 85 for each individual light-emitting element 53. In a similar manner, according to the upper optical element 72 as Figure 10 shown, for example, it is easier to control the liquid crystal layer 95 for each individual light-emitting element 53.

[0134] On the other hand, according to the one such as Figure 4The lower optical element 71 shown, for example, can more easily control the liquid crystal layer 85 for the plurality of light-emitting elements 53. In a similar manner, according to the upper optical element 72 shown as Figure 4 for example, the liquid crystal layer 95 for the plurality of light-emitting elements 53 can be more easily controlled. For example, this is useful when a large lens L2 as shown in Figure 4 is to be generated. Note that Figure 10 the lens L2 shown is a small lens similar to the lens L1.

[0135] Figure 11 is a plan view showing an example of the structure of the lower optical element 71 shown as Figure 10 The positional relationship among the lower electrode 81, the liquid crystal layer 85, and the liquid crystal seal 87 of the lower optical element 71 is shown.

[0136] Figure 11 The position of the light-emitting element 53 and the position of the light-transmitting region R are also shown. Figure 11 In the region shown as

[0137] In Figure 11 the region shown, the liquid crystal layer 85 for two light-emitting elements 53 is surrounded by the liquid crystal seal 87 for each light-emitting element 53. For example, in the lower optical element 71 according to this modification, the liquid crystal layer 85 for N light-emitting elements 53 is divided into N regions and sealed, where N is an integer equal to or greater than 2. In this way, the liquid crystal layer 85 according to this modification is divided into a plurality of regions and sealed in one-to-one correspondence with the light-emitting elements 53, and the number of the plurality of regions is the same as the number of the light-emitting elements 53. The same description applies to the upper optical element 72.

[0138] Figure 12 is a cross-sectional view showing the structure of the light-emitting device 1 according to another modification of the first embodiment.

[0139] The lower optical element 71 according to this modification includes a column 89 provided between the substrates 73 and 74. Although the column 89 is provided between the light-transmitting regions R in a manner similar to that of Figure 10 the liquid crystal seal 87 shown, the column 89 does not divide the liquid crystal layer 85 for each light-emitting element 53. The column 89 can be formed of any material as long as the material enables adjustment of the gap between the substrates 73 and 74.

[0140] In a similar manner, the upper optical element 72 according to this modification includes a column 99 provided between the substrates 74 and 75. Although the column 99 is provided in a manner similar to that of Figure 10It is disposed between the light transmission regions R in the manner of the liquid crystal seal 97 shown, but the column 99 does not divide the liquid crystal layer 95 for each light-emitting element 53. The column 99 can be formed of any material as long as the material enables adjustment of the gap between the substrates 74 and 75.

[0141] Figure 13 is a plan view showing Figure 12 an example of the structure of the lower optical element 71 shown.

[0142] Figure 13 shows the positional relationship between the lower electrode 81, the liquid crystal layer 85, the liquid crystal seal 87, and the column 89 of the lower optical element 71. Figure 13 Also shown are the positions of the light-emitting elements 53 and the positions of the light transmission regions R.

[0143] In Figure 13 the region shown (unit seal region), the liquid crystal layer 85 for two light-emitting elements 53 is surrounded by the liquid crystal seal 87 in a ring shape. The lower optical element 71 according to this modification includes a plurality of such unit seal regions. For example, the lower optical element 71 according to this modification includes four liquid crystal layers 85 for eight light-emitting elements 53 inside four unit seal regions. In this way, the liquid crystal layer 85 according to this modification is divided into a plurality of unit seal regions and sealed, and the number of the plurality of unit seal regions is less than the number of the light-emitting elements 53. In addition, each unit seal region includes a column 89 between the light transmission regions R. The same description applies to the upper optical element 72.

[0144] Figure 14 is a plan view showing Figure 4 various examples of the structure of the lower optical element 71 shown.

[0145] Figure 14 A in Figure 5 shows two unit seal regions. Each unit seal region has Figure 14 the structure shown. In

[0146] Although Figure 14 B in Figure 14 shows a region of the same size as A in Figure 14 but the liquid crystal seal 87 between the two unit seal regions is removed. The region shown by B in

[0147] AlthoughFigure 14 C in Figure 14 shows a region of the same size as B in Figure 14 ; however, C in Figure 14 further shows a light-emitting element 53 and a light-transmitting region R. The region shown by C in

[0148] can be described as a single unit-sealed region provided with a single liquid crystal layer 85 for five light-emitting elements 53. In this way, the number of light-emitting elements 53 per unit-sealed region can be any number. The lower optical element 71 according to this example includes such a unit-sealed region.

[0149] (Second Embodiment)

[0150] Figure 15 is a cross-sectional view showing the structure of the light-emitting device 1 according to the second embodiment.

[0151] The light-emitting device 1 according to this embodiment has a structure similar to that of the light-emitting device 1 shown in Figure 8 . However, the upper optical element 72 according to this embodiment includes a liquid crystal layer 95 serving as a diffraction grating G2. This diffraction grating G2 can also be referred to as a diffractive optical element (DOE). For example, the diffraction grating G2 has a shape including a plurality of light-shielding portions and a plurality of light-transmitting portions extending alternately in the Y direction.

[0152] The light-emitting device 1 according to this embodiment further includes two lenses 79a and 79b as optical elements 79 provided above the substrate 75. Although the lenses 79a and 79b are a convex lens and a concave lens, respectively, in Figure 15 , the lenses 79a and 79b can be other lenses.

[0153] The diffraction grating G2 according to this embodiment can switch between outputting the light incident via a single lens L1 from a single light-emitting element 53 to the lens 79a and outputting the light to the lens 79b. For example, when a given voltage is applied to the liquid crystal layer 95, the light is output from the diffraction grating G2 to the lens 79a. In addition, when another voltage is applied to the liquid crystal layer 95, the light is output from the diffraction grating G2 to the lens 79b. In this way, the diffraction grating G2 according to this embodiment can be used as a prism for controlling the optical path.

[0154] In the present embodiment, the diffraction grating G2 that produces this effect is realized by the liquid crystal layer 95. Therefore, the characteristics of the diffraction grating G2 can be changed by driving the liquid crystal layer 95 (optically variable diffraction grating). For example, the width, length, and pitch of the light-shielding portion of the diffraction grating G2 and the width, length, and pitch of the light-transmitting portion of the diffraction grating G2 can be adjusted to values suitable for outputting light to the lenses 79a and 79b. In addition, by variously adjusting the characteristics of the diffraction grating G2, the number of optical elements of the light-emitting device 1 can be reduced, and miniaturization and weight reduction of the light-emitting device 1 can be achieved. In this way, according to the present embodiment, the light emitted from the light-emitting element 53 can be appropriately controlled by the diffraction grating G2 inside the liquid crystal layer 95.

[0155] Figure 16 is a plan view showing Figure 15 an example of the structure of the lower electrode 91 shown. The lower electrode 91 according to the present embodiment can be configured as in this example.

[0156] In Figure 16 the example shown, the lower electrode 91 includes a plurality of linear electrodes 91a arranged in parallel with each other. The electrodes 91a are adjacent to each other in the x direction and extend in the Y direction. When a voltage is applied to the liquid crystal layer 95 from the lower electrode 91, a diffraction grating G2 is generated inside the liquid crystal layer 95, and the light incident on the diffraction grating G2 is output to the lens 79a or the lens 79b. Since the electrodes 91a are shaped to extend in the Y direction in a manner similar to the light-shielding portion and the light-transmitting portion of the diffraction grating G2, the electrodes 91a are suitable for generating the diffraction grating G2 inside the liquid crystal layer 95. Ideally, the electrodes 91a can be driven independently of each other. In addition, the upper electrode 92 can be configured as in this example in a manner similar to or instead of the lower electrode 91.

[0157] Figure 17 is a plan view showing the structure of the upper optical element 72 according to a modification of the second embodiment.

[0158] The lower optical element 72 according to this modification includes side electrodes 91' and 92' instead of the lower electrode 91 and the upper electrode 92. Contrary to the lower electrode 91 and the upper electrode 92 being arranged on the lower surface and the upper surface of the liquid crystal layer 95 to sandwich the liquid crystal layer 95, the side electrodes 91' and 92' are arranged on the side surfaces of the liquid crystal layer 95 to sandwich the liquid crystal layer 95. The lower surface, the upper surface, and the side surfaces of the liquid crystal layer 95 are examples of the first surface, the second surface, and the third surface of the liquid crystal layer according to the present disclosure. In the present embodiment, the side electrode 91' is arranged on the side surface of the liquid crystal layer 95 in the -X direction, and the side electrode 92' is arranged on the side surface of the liquid crystal layer 95 in the +x direction.

[0159] With the side electrodes 91' and 92' according to this modification, a voltage that changes in the X direction can be applied to the light traveling in the z direction. Therefore, for example, the polarization direction of the light can be changed by the liquid crystal layer 95. Although in this modification, the lower optical element 72 includes the side electrodes 91' and 92' instead of the lower electrode 91 and the upper electrode 92, alternatively, in addition to the lower electrode 91 and the upper electrode 92, the lower optical element 72 may include the side electrodes 91' and 92'.

[0160] It should be noted that the side electrodes 91' and 92' according to this modification can be configured as opaque electrodes instead of being configured as transparent electrodes. This is because the arrangement of the side electrodes 91' and 92' according to this modification outside the light transmission region R eliminates the need for light to pass through the side electrodes 91' and 92'.

[0161] As described above, the light-emitting device 1 according to this embodiment includes the liquid crystal layer 95 that serves as the diffraction grating G2. Therefore, according to this embodiment, the light emitted from the light-emitting element 53 can be appropriately controlled by the diffraction grating G2. For example, by adjusting the diffraction grating G2, the light from the light-emitting element 53 can be output to the positions of the lens 79a and the lens 79b.

[0162] It should be noted that the liquid crystal layer 95 according to this embodiment can be controlled so as to not only output the light from the light-emitting element 53 to the lens 79a or the lens 79b, but also block the light from the light-emitting element 53 in a manner similar to the third embodiment described later. Therefore, the switching between outputting the light to the lens 79a or the lens 79b and blocking the light can be performed.

[0163] (Third Embodiment)

[0164] Figure 18 is a cross-sectional view showing the structure of the light-emitting device 1 according to the third embodiment.

[0165] The light-emitting device 1 according to this embodiment has a structure similar to that of the Figure 8 light-emitting device 1 shown. However, the upper optical element 72 according to this embodiment includes the liquid crystal layer 95 that serves as a light valve.

[0166] The liquid crystal layer 95 according to this embodiment can switch between transmitting the light incident from the light-emitting element 53 via the lens L1 and blocking the light. For example, when a given voltage is applied to the liquid crystal layer 95, the light valve of the liquid crystal layer 95 opens, and the light from the lens L1 is transmitted through the liquid crystal layer 95. In addition, when another voltage is applied to the liquid crystal layer 95, the light valve of the liquid crystal layer 95 closes, and the light from the lens L1 is blocked by the liquid crystal layer 95. In this case, the liquid crystal layer 95 can absorb the light from the lens L1 or reflect the light from the lens L1.

[0167] In the present embodiment, the light valve that produces this effect is realized by the liquid crystal layer 95. Therefore, the characteristics of the light valve can be changed by driving the liquid crystal layer 95 (optical variable light valve). For example, the light transmittance when the light valve is opened can be adjusted to a desired value. In addition, by making various adjustments to the characteristics of the light valve, the number of optical elements of the light-emitting device 1 can be reduced, and the light-emitting device 1 can be miniaturized and lightened. In this way, according to the present embodiment, the light emitted from the light-emitting element 53 can be appropriately controlled by the light valve inside the liquid crystal layer 95.

[0168] It should be noted that the shapes of the lower electrode 91 and the upper electrode 92 according to the present embodiment can be any shape as long as a light valve can be generated inside the liquid crystal layer 95.

[0169] Figure 19 is a timing chart showing an operation example of the light-emitting device 1 according to the third embodiment.

[0170] Figure 19 shows the activation of the light-emitting device 1, the driving of the light-emitting element 53, the driving of the liquid crystal layer 95, and the projection of light onto an object (see Figure 1 ) timing. In Figure 19 the example shown, when the light-emitting device 1 is activated, the light-emitting element 53 is continuously driven and continuously emits light. On the other hand, the liquid crystal layer 95 is controlled so that the driving state and the non-driving state are alternately repeated. Therefore, the light valve inside the liquid crystal layer 95 is operated so that the on (light transmission) state and the off (light shielding) state are alternately repeated. Therefore, even if the light-emitting element 53 continuously emits light, the light projected onto the object changes so that the on state and the off state are alternately repeated. Therefore, the object can be irradiated with light that changes in a pulsed manner.

[0171] As described above, the light-emitting device 1 according to the present embodiment includes the liquid crystal layer 95 that serves as a light valve. Therefore, according to the present embodiment, the light emitted from the light-emitting element 53 can be appropriately controlled by the light valve.

[0172] (Modification of the First Embodiment)

[0173] Figure 20 is a cross-sectional view showing the structure of the light-emitting device 1 according to various modifications of the first embodiment.

[0174] In Figure 20 the modification shown in A, the upper optical element 72 is not stacked on the lower optical element 71, but is arranged at a position separated from the lower optical element 71. The upper optical element 72 according to this modification receives the light that passes through the first optical element 71 and is reflected by the mirror 101.

[0175] Even in Figure 20In the modification shown in B, the upper optical element 72 is not stacked on the lower optical element 71 either, but is arranged at a position separated from the lower optical element 71. The upper optical element 72 according to this modification reflects the light passing through the first optical element 71 with the liquid crystal layer 95.

[0176] Even in Figure 20 In the modification shown in C, the upper optical element 72 is not stacked on the lower optical element 71 either, but is arranged at a position separated from the lower optical element 71. The upper optical element 72 according to this modification receives the light passing through the lower optical element 71 and reflected by the mirror 102 and reflects the light with the liquid crystal layer 95. The light reflected by the liquid crystal layer 95 is reflected by the mirror 102 and irradiates the object. In addition, the light reflected by the object passes through the mirror 102 and is received by the sensor 103. For example, the sensor 103 is Figure 1 the image sensor 21 shown.

[0177] According to these modifications, for example, the control of the light between the lower optical element 71 and the upper optical element 72 and the positional relationship between the lower optical element 71 and the second optical element 72 can be freely designed. It should be noted that the upper optical element 72 according to the modification does not need to be arranged at a position higher than the position of the lower optical element 71. In addition, the liquid crystal layer 95 according to the modification can be used as an optical element other than the lens L2.

[0178] Although the light-emitting device 1 according to each embodiment or its modification is used as the light source of the distance measuring device, the light-emitting device 1 can be used in other aspects. For example, the light-emitting device 1 can be used as the light source of an optical device such as a printer or as a lighting device.

[0179] Although the embodiments of the present disclosure have been described above, various modifications of the embodiments can be realized without departing from the gist of the present disclosure. For example, two or more embodiments can be combined and realized.

[0180] The present disclosure can also be configured as follows. (1)

[0182] A light-emitting device, comprising:

[0183] A substrate;

[0184] A plurality of light-emitting elements provided on the first surface side of the substrate; and

[0185] An optical element provided on the second surface side of the substrate, and the light emitted from the plurality of light-emitting elements is incident on the optical element, wherein,

[0186] The optical element includes a liquid crystal layer configured to be used as a lens. (2)

[0188] The light-emitting device according to (1), wherein,

[0189] The optical element includes:

[0190] A first optical element, to which light emitted from a plurality of light-emitting elements is incident; and

[0191] A second optical element, to which the light that has passed through the first optical element is incident, wherein,

[0192] At least one of the first optical element and the second optical element includes a liquid crystal layer configured to function as a lens. (3)

[0194] The light-emitting device according to (2), wherein,

[0195] The first optical element includes a liquid crystal layer configured to function as a plurality of first lenses, and light emitted from a plurality of light-emitting elements is incident on the first lenses; and

[0196] The second optical element includes a liquid crystal layer configured to function as a second lens, and the light that has passed through the plurality of first lenses is incident on the second lens. (4)

[0198] The light-emitting device according to (2), wherein,

[0199] The first optical element includes a liquid crystal layer configured to function as a plurality of first lenses, and light emitted from a plurality of light-emitting elements is incident on the first lenses; and

[0200] The second optical element includes a second lens that is not a liquid crystal, and the light that has passed through the plurality of first lenses is incident on the second lens. (5)

[0202] The light-emitting device according to (2), wherein,

[0203] The first optical element includes a plurality of first lenses that are not a liquid crystal, and light emitted from a plurality of light-emitting elements is incident on the plurality of first lenses; and

[0204] The second optical element includes a liquid crystal layer configured to function as a second lens, and the light that has passed through the plurality of first lenses is incident on the second lens.

[0205] (h)

[0206] The light-emitting device according to (1), wherein,

[0207] The optical element includes:

[0208] A first electrode provided on one side of the substrate of the liquid crystal layer; and

[0209] The second electrode is disposed on a side of the liquid crystal layer opposite to the substrate. (7)

[0211] The light-emitting device according to (6), wherein the first electrode or the second electrode includes a plurality of electrodes having an annular shape. (8)

[0213] The light-emitting device according to (6), wherein the first electrode or the second electrode includes a plurality of electrodes arranged in a square lattice shape. (9)

[0215] The light-emitting device according to (1), wherein

[0216] the liquid crystal layer is sandwiched between the first substrate and the second substrate; and

[0217] a lens is disposed on a surface of at least one of the first substrate and the second substrate. (10)

[0219] The light-emitting device according to (1), wherein the liquid crystal layer is divided into a plurality of regions and sealed to correspond to a plurality of light-emitting elements one by one. (11)

[0221] The light-emitting device according to (1), wherein the liquid crystal layer is divided into a plurality of regions and sealed, and the number of the plurality of regions is less than the number of the plurality of light-emitting elements. (12)

[0223] The light-emitting device according to (1), wherein the substrate is a semiconductor substrate containing gallium (Ga) and arsenic (As). (13)

[0225] The light-emitting device according to (1), wherein light emitted from the plurality of light-emitting elements is transmitted from a first surface to a second surface inside the substrate and incident on an optical element. (14)

[0227] The light-emitting device according to (1), wherein the first surface of the substrate is the front surface of the substrate, and the second surface of the substrate is the back surface of the substrate. (15)

[0229] The light-emitting device according to (1), further comprising a driving device disposed on a first surface side of the substrate via the plurality of light-emitting elements and configured to drive the plurality of light-emitting elements. (16)

[0231] The light-emitting device according to (15), wherein the driving device is configured to drive the plurality of light-emitting elements on an individual basis. (17)

[0233] The light-emitting device according to (15), wherein the driving device is further configured to drive the liquid crystal layer. (18)

[0235] The light-emitting device according to (2), wherein the second optical element is configured to receive the light that passes through the first optical element and is reflected by the mirror, reflect the light that passes through the first optical element, or receive the light that passes through the first optical element and passes through the mirror. (19)

[0237] A light-emitting device, comprising:

[0238] A substrate;

[0239] A light-emitting element provided on the first surface side of the substrate; and

[0240] An optical element provided on the second surface side of the substrate, and the light emitted from the light-emitting element is incident on the optical element, wherein

[0241] The optical element includes a liquid crystal layer configured to function as a diffraction grating. (20)

[0243] The light-emitting device according to (19), wherein

[0244] The optical element includes:

[0245] A first electrode provided on one side of the substrate of the liquid crystal layer; and

[0246] A second electrode provided on the side of the liquid crystal layer opposite to the substrate.

[0247] (2,(1))

[0248] The light-emitting device according to (20), wherein the first electrode or the second electrode includes a plurality of linear electrodes arranged parallel to each other. (22)

[0250] The light-emitting device according to (19), wherein

[0251] The liquid crystal layer has a first surface on one side of the substrate, a second surface on the side opposite to the substrate, and a third surface between the first surface and the second surface; and

[0252] The optical element includes a first electrode and a second electrode, and the first electrode and the second electrode are provided to sandwich the liquid crystal layer on the third surface of the liquid crystal layer. (23)

[0254] A light-emitting device, comprising:

[0255] A substrate;

[0256] A light-emitting element, disposed on the first surface side of a substrate; and

[0257] An optical element, disposed on the second surface side of the substrate, and light emitted from the light-emitting element is incident on the optical element, wherein

[0258] the optical element includes a liquid crystal layer configured to function as a light valve. (24)

[0260] The light-emitting device according to (23), wherein, while continuously emitting light from the light-emitting element, the light-emitting device controls the on / off of the light emitted from the light-emitting device by controlling the on / off of the light valve.

[0261] List of reference numerals

[0262] 1 Light-emitting device

[0263] 2 Imaging device

[0264] 3 Control device

[0265] 11 Light-emitting unit

[0266] 12 Driving circuit

[0267] 13 Power supply circuit

[0268] 14 Light-emitting side optical system

[0269] 21 Image sensor

[0270] 22 Image processing unit

[0271] 23 Imaging side optical system

[0272] 31 Distance measuring unit

[0273] 41 LD chip

[0274] 42 LDD substrate

[0275] 43 Mounting substrate

[0276] 44 Heat dissipation substrate

[0277] 45 Correction lens holding unit

[0278] 46 Correction lens

[0279] 47 Wiring

[0280] 48 Bump

[0281] 51 Substrate

[0282] 52 Laminated film

[0283] 53 Light-emitting element

[0284] 54 Anode electrode

[0285] 55 Cathode electrode

[0286] 61 Substrate

[0287] 62 Connection pad

[0288] 71 Lower optical element

[0289] 72 Upper optical element

[0290] 73, 74, 75 Substrate

[0291] 74a, 75a Protrusion

[0292] 74b, 75b Recess

[0293] 76 Wiring

[0294] 77 Liquid crystal drive unit

[0295] 78 Liquid crystal drive element

[0296] 79 Optical element

[0297] 79a, 79b Lens

[0298] 81 Lower electrode

[0299] 81a, 81b Electrode

[0300] 82 Upper electrode

[0301] 83 Lower alignment film

[0302] 84 Upper alignment film

[0303] 85 Liquid crystal layer

[0304] 86 Spacer material

[0305] 87 Liquid crystal sealant

[0306] 88 Lens film

[0307] 88a First lens film

[0308] 88b Second lens film

[0309] 89 Post

[0310] 91 Lower electrode

[0311] 91’ Side electrode

[0312] 91a Electrode

[0313] 92 Upper electrode

[0314] 92’ Side electrode

[0315] 93 Lower alignment film

[0316] 94 Upper alignment film

[0317] 95 Liquid crystal layer

[0318] 96 Spacer material

[0319] 97 Liquid crystal sealant

[0320] 98 Lens film

[0321] 99 Post

[0322] 101 Mirror

[0323] 102 Mirror

[0324] 103 Sensor.

Claims

1. A light-emitting device, comprising: a substrate; a plurality of light-emitting elements disposed on a first surface side of the substrate; and an optical element disposed on a second surface side of the substrate, and light emitted from the plurality of light-emitting elements is incident on the optical element, wherein the optical element includes a liquid crystal layer configured to function as a lens, wherein the light-emitting device further includes a driving device, the driving device is disposed on the first surface side of the substrate via the plurality of light-emitting elements and is configured to drive the plurality of light-emitting elements, wherein the driving device is configured to drive the plurality of light-emitting elements on an individual basis, wherein the liquid crystal layer is sandwiched between a first substrate and a second substrate; wherein the optical element includes: a first electrode disposed on an upper surface of the first substrate; and a second electrode disposed on a lower surface of the second substrate; wherein the first electrode and the second electrode are used to drive the liquid crystal layer and to control the orientation of liquid crystal molecules inside the liquid crystal layer; wherein a lower alignment film is disposed on the upper surface of the first substrate via the first electrode, and an upper alignment film is disposed on the lower surface of the second substrate via the second electrode, and the lower alignment film and the upper alignment film have a plurality of grooves for aligning liquid crystal molecules inside the liquid crystal layer, and wherein the liquid crystal layer is disposed between the lower alignment film and the upper alignment film, and the liquid crystal layer functions as a lens by being driven by the first electrode and the second electrode.

2. The light-emitting device according to claim 1, wherein the optical element includes: a first optical element, light emitted from the plurality of light-emitting elements is incident on the first optical element; and a second optical element, light passing through the first optical element is incident on the second optical element, wherein at least any one of the first optical element and the second optical element includes a liquid crystal layer configured to function as a lens.

3. The light-emitting device according to claim 2, wherein the first optical element includes a liquid crystal layer configured to function as a plurality of first lenses, and light emitted from the plurality of light-emitting elements is incident on the plurality of first lenses; and the second optical element includes a liquid crystal layer configured to function as a second lens, and light passing through the plurality of first lenses is incident on the second lens.

4. The light-emitting device according to claim 2, wherein the first optical element includes a liquid crystal layer configured to function as a plurality of first lenses, and light emitted from the plurality of light-emitting elements is incident on the plurality of first lenses; and the second optical element includes a second lens that is not a liquid crystal, and light passing through the plurality of first lenses is incident on the second lens.

5. The light-emitting device according to claim 2, wherein the first optical element includes a plurality of first lenses that are not a liquid crystal, and light emitted from the plurality of light-emitting elements is incident on the plurality of first lenses; and the second optical element includes a liquid crystal layer configured to function as a second lens, and light passing through the plurality of first lenses is incident on the second lens.

6. The light-emitting device according to claim 1, wherein the first electrode or the second electrode includes a plurality of electrodes having an annular shape.

7. The light-emitting device according to claim 1, wherein, The first electrode or the second electrode includes a plurality of electrodes arranged in a square lattice shape.

8. The light-emitting device according to claim 1, wherein A lens is provided on the surface of at least any one of the first substrate and the second substrate.

9. The light-emitting device according to claim 1, wherein, The liquid crystal layer is divided into a plurality of regions and sealed to correspond to the plurality of light-emitting elements one by one.

10. The light-emitting device according to claim 1, wherein, The liquid crystal layer is divided into a plurality of regions and sealed, and the number of the plurality of regions is less than the number of the plurality of light-emitting elements.

11. The light-emitting device according to claim 1, wherein, The substrate is a semiconductor substrate containing gallium and arsenic.

12. The light-emitting device according to claim 1, wherein, The light emitted from the plurality of light-emitting elements is transmitted from the first surface to the second surface inside the substrate and incident on the optical element.

13. The light-emitting device according to claim 1, wherein the first surface of the substrate is the front surface of the substrate, and the second surface of the substrate is the back surface of the substrate.

14. The light-emitting device according to claim 1, wherein, The driving device is further configured to drive the liquid crystal layer.

15. The light-emitting device according to claim 2, wherein, The second optical element is configured to receive the light that passes through the first optical element and is reflected by the mirror, reflect the light that passes through the first optical element, or receive the light that passes through the first optical element and passes through the mirror.

16. A light-emitting device, comprising: A substrate; A light-emitting element provided on the first surface side of the substrate; And An optical element provided on the second surface side of the substrate, and the light emitted from the light-emitting element is incident on the optical element, wherein the optical element includes a liquid crystal layer configured to be used as a diffraction grating, and wherein the liquid crystal layer has a first surface on one side of the substrate, a second surface on the side opposite to the substrate, and a third surface between the first surface and the second surface; and The optical element includes a first electrode and a second electrode, and the first electrode and the second electrode are provided to sandwich the liquid crystal layer on the third surface of the liquid crystal layer.

17. The light-emitting device according to claim 16, wherein The optical element includes: A first electrode provided on the side of the substrate of the liquid crystal layer; and A second electrode provided on the side opposite to the substrate of the liquid crystal layer.

18. The light-emitting device according to claim 17, wherein the first electrode or the second electrode includes a plurality of linear electrodes arranged parallel to each other.

19. A light-emitting device, comprising: A substrate; A light-emitting element provided on the first surface side of the substrate; And An optical element provided on the second surface side of the substrate, and the light emitted from the light-emitting element is incident on the optical element, wherein the optical element includes a liquid crystal layer configured to be used as a light valve, and wherein when the light-emitting device is activated, the light-emitting element is continuously driven and continuously emits light, and the liquid crystal layer is controlled such that the driving state and the non-driving state are alternately repeated.

20. The light-emitting device according to claim 19, wherein, While continuously emitting light from the light-emitting element, the light-emitting device controls the turning on / off of the light emitted from the light-emitting device by controlling the turning on / off of the light valve.

Images