Patent Description:
Patent Document <NUM> discloses an imaging device including: a light source; a light diffusing member that has plural lenses arranged adjacent to each other on a predetermined plane and diffuses light emitted from the light source; and an imaging element that receives reflected light obtained by reflecting the light diffused by the light diffusing member by a subject. The plural lenses are arranged such that a period of interference fringes in the diffused light is three pixels or less. <CIT> shows a light emitting device with a wiring substrate and a base member which is supposed to be "the base of chip <NUM>". Light sources <NUM> are mounted on the base member. <CIT> shows a light emitting device with a wiring substrate <NUM>. A light source (laser) is mounted on the base member, wherein layers are interposed between the light source and the base member. <CIT> discloses a substrate arrangement. <CIT> contains more background information concerning the field of the invention.

When it is desired to reduce inductance of a circuit that drives a light source, a wiring such as a bonding wire may be provided not only on one side surface side of the light source but also on plural side surface sides. In addition, a circuit element such as a light receiving element that detects an amount of light emitted from the light source may be disposed close to a side surface of the light source.

In such a case, a configuration is conceivable in which a circuit element is disposed on a drive unit side of the light source, and a wiring such as a bonding wire is provided on another side surface side. However, when the circuit element is disposed between the light source and the drive unit, a path of a wiring pattern that connects the light source and the drive unit is restricted, and the inductance of the circuit may increase.

At least one embodiment of the present invention provides a light-emitting device or the like having a structure in which a path of a wiring pattern is less likely to be restricted by a circuit element in a configuration in which the circuit element is disposed between a light source and a drive unit, as compared with a configuration in which a wiring pattern connecting a light source and a drive unit and a circuit element are both provided on a wiring substrate.

The problem is solved by the invention defined in the independent claims. According to a first aspect of the present invention, there is provided a light-emitting device, including: a wiring substrate; a base member that is mounted on the wiring substrate; a light source that is mounted on the base member; a drive unit that is mounted on the wiring substrate and drives the light source; a wiring pattern that is on the wiring substrate, is connected to the light source and extends from a back surface side of the base member toward the drive unit; and a circuit element that is provided in a region on the front surface of the base member between the light source and the drive unit, the region overlapping the wiring pattern in a plan view, so that a path of the wiring pattern connecting the light source and the drive unit is not restricted by the circuit element.

A second aspect of the present invention is the light-emitting device according to the first aspect, in which the circuit element is electrically connected to the wiring substrate, and the wiring pattern is wired without avoiding a connection portion between the circuit element and the wiring substrate.

A third aspect of the present invention is the light-emitting device according to the first or second aspect, in which the circuit element includes a first electrode and a second electrode, wherein the first electrode and the second electrode are separated on two sides of the circuit element to sandwich a light-source cathode wiring pattern provided on the wiring substrate, and are connected to a circuit element anode wiring pattern and a circuit cathode wiring pattern.

A fourth aspect of the present invention is the light-emitting device according to any one of the first to third aspects, in which the light source is a light-emitting element array that includes a first side surface and a second side surface facing each other, and a third side surface and a fourth side surface facing each other and connecting the first side surface and the second side surface, and a wiring extending from an upper-surface electrode of the light-emitting element array toward an outer side of the light-emitting element array is provided at least at a side of the first side surface and the second side surface, the circuit element is provided on the base member at a side of the fourth side surface, and the wiring pattern extends from the side of the fourth side surface toward the drive unit.

A fifth aspect of the present invention is the light-emitting device according to the fourth aspect, in which the wiring extending from an upper-surface electrode of the light-emitting element array toward an outer side of the light-emitting element array is provided at a side of the third side surface.

A sixth aspect of the present invention is the light-emitting device according to the fourth aspect, in which another circuit element is provided on the base member at a side of the third side surface.

A seventh aspect of the present invention is the light-emitting device according to the sixth aspect, in which at least one of the circuit element and the other circuit element is a light receiving element.

An eighth aspect of the present invention is the light-emitting device according to any one of the first to seventh aspects, in which the base member is a member having a higher thermal conductivity than the wiring substrate.

A ninth aspect of the present invention is the light-emitting device according to the eighth aspect, in which the base member on the wiring substrate is made of ceramic.

A tenth aspect of the present invention is the light-emitting device according to any one of the fourth to seventh aspects, in which a light diffusing member that diffuses, toward an outside, light emitted from the light source is provided on an emission path of the light-emitting element array in the light source.

An eleventh aspect of the present invention is the light-emitting device according to any one of the fourth to seventh aspects, in which the light-emitting element array includes plural light-emitting elements connected in parallel to one another.

According to a twelfth aspect of the present invention, there is provided a light-emitting device including: a wiring substrate; a light source and a drive unit driving the light source that are mounted on the wiring substrate; a wiring pattern that is on the wiring substrate and connects the light source and the drive unit; a base member that is provided across the wiring pattern between the light source and the drive unit; and a circuit element that is provided in a region on the front surface of the base member, the region overlapping the wiring pattern in a plan view, so that a path of the wiring pattern connecting the light source and the drive unit is not restricted by the circuit element.

According to a thirteenth aspect of the present invention, there is provided an optical device including: the light-emitting device according to any one of the first to twelfth aspects; and a light receiving unit that receives reflected light emitted from the light source included in the light-emitting device and reflected by an object to be measured, in which the light receiving unit outputs a signal corresponding to a time from when light is emitted from the light source to when the light is received by the light receiving unit.

According to a fourteenth aspect of the present invention, there is provided an information processing device including: the optical device according to the thirteenth aspect; and a shape specifying unit that specifies a three-dimensional shape of an object to be measured based on reflected light that is emitted from the light source included in the optical device, reflected by the object to be measured, and received by the light receiving unit included in the optical device.

A fifteenth aspect of the present invention is the information processing device according to the fourteenth aspect, further including: an authentication processing unit that performs authentication processing related to use of the information processing device based on a specified result of the shape specifying unit.

According to the invention of the first aspect and the twelfth aspect, a path of a wiring pattern is less likely to be restricted by the circuit element, as compared with a configuration in which the wiring pattern connecting the light source and the drive unit and the circuit element are provided on the wiring substrate.

According to the invention of the second aspect, the path of the wiring pattern is not affected by the connection portion between the circuit element and the wiring substrate.

According to the invention of the third aspect, a size of the light-emitting device is easily reduced as compared with a case where the first electrode and the second electrode are connected to the wiring substrate on one side in the width direction of the wiring pattern.

According to the invention of the fourth aspect, inductance of the circuit is reduced as compared with a case where the wiring extending from the upper-surface electrode toward the outer side is provided only on one side surface side of the light-emitting element array.

According to the invention of the fifth aspect, the inductance of the circuit is reduced as compared with a case where the wiring extending from the upper-surface electrode toward the outer side is provided only on two side surface sides of the light-emitting element array.

According to the invention of the sixth aspect, heat dissipation effect is higher than in a case where other circuit elements are not provided.

According to the invention of the seventh aspect, light emitted from the light source is detected.

According to the invention of the eighth aspect, the heat dissipation effect is higher than in a case where the base member has the same thermal conductivity as the wiring substrate.

According to the invention of the ninth aspect, the heat dissipation effect is higher than in a case where the base member is made of resin.

According to the invention of the tenth aspect, light emitted from the light source is radiated in a wide range as compared with a configuration in which the light diffusing member is not provided.

According to the invention of the eleventh aspect, light of a high intensity is simultaneously radiated as compared with a configuration in which the light-emitting elements are individually driven.

According to the present invention of the thirteenth aspect, there is provided an optical device capable of performing three-dimensional measurement.

According to the present invention of the fourteenth aspect, there is provided an information processing device capable of measuring a three-dimensional shape.

According to the present invention of the fifteenth aspect, there is provided an information processing device loaded with authentication processing based on a three-dimensional shape.

In many cases, an information processing device identifies whether a user who has accessed the information processing device is permitted to access the information processing device, and permits use of the information processing device that is an own device only when it is authenticated that the user is an user whose access is permitted. A method for authenticating a user by a password, a fingerprint, an iris, or the like has been used so far. Recently, there is a demand for an authentication method having a higher security. Such a method includes performing authentication based on a three-dimensional image such as a shape of a face of a user.

Here, an example in which the information processing device is a portable information processing terminal will be described, and the information processing device authenticates a user by recognizing a shape of a face that is captured as a three-dimensional image. The information processing device can be applied to an information processing device such as a personal computer (PC) other than a portable information processing terminal.

Furthermore, the configuration, function, method, and the like described in the present embodiment can also be applied to recognition of a three-dimensional shape other than recognition of a shape of a face. That is, the present invention may be applied to recognize a shape of an object other than a face. Further, a distance to an object to be measured is not limited.

<FIG> is a diagram illustrating an example of an information processing device <NUM>. As described above, the information processing device <NUM> is, for example, a portable information processing terminal.

The information processing device <NUM> includes a user interface unit (hereinafter, referred to as a UI unit) <NUM> and an optical device <NUM> that acquires a three-dimensional image. The UI unit <NUM> is configured by integrating, for example, a display device that displays information to a user and an input device to which an instruction for information processing is input by an operation of the user. The display device is, for example, a liquid crystal display or an organic EL display, and the input device is, for example, a touch panel.

The optical device <NUM> includes a light-emitting device <NUM> and a three-dimensional sensor (hereinafter, referred to as a 3D sensor) <NUM>. The light-emitting device <NUM> radiates light toward an object to be measured, that is, a face in the example described here, in order to acquire a three-dimensional image thereof. The 3D sensor <NUM> acquires the light that is radiated by the light-emitting device <NUM>, is reflected by the face, and is returned. Here, the three-dimensional image of the face is acquired based on a so-called time of flight (TOF) method based on flight time of light. Hereinafter, in a case of acquiring a three-dimensional image of a face, the face is referred to as an object to be measured. Note that a three-dimensional image other than that of a face may be acquired. The acquisition of a three-dimensional image may be referred to as 3D sensing. The 3D sensor <NUM> is an example of a light receiving unit.

The information processing device <NUM> is configured as a computer including a CPU, a ROM, a RAM, and the like. The ROM includes a non-volatile rewritable memory such as a flash memory. Further, programs and constants stored in the ROM are loaded to the RAM and are executed by the CPU, so that the information processing device <NUM> is operated and various types of information processing are executed.

<FIG> is a block diagram illustrating a configuration of the information processing device <NUM>.

The information processing device <NUM> includes the optical device <NUM> described above, an optical device control unit <NUM>, and a system control unit <NUM>. The optical device control unit <NUM> controls the optical device <NUM>. The optical device control unit <NUM> includes a shape specifying unit <NUM>. The system control unit <NUM> controls the entire information processing device <NUM> as a system. The system control unit <NUM> includes an authentication processing unit <NUM>. The UI unit <NUM>, a speaker <NUM>, and a two-dimensional camera (indicated by a 2D camera in <FIG>) <NUM>, and the like are connected to the system control unit <NUM>.

Hereinafter, the components described above will be described in order.

The light-emitting device <NUM> included in the optical device <NUM> includes a wiring substrate <NUM>, a base member <NUM>, a light source <NUM>, a light diffusing member <NUM>, and a light receiving element <NUM> for monitoring a light amount (indicated by PD in <FIG> and the following description), a drive unit <NUM>, a holding portion <NUM> and a capacitor <NUM>. The light-emitting device <NUM> further includes passive elements such as a resistor element <NUM> and a capacitor <NUM> in order to operate the drive unit <NUM>. Although two capacitors <NUM> are shown, one capacitor <NUM> may be provided or more than two capacitors <NUM> may be provided. Further, a plural resistor elements <NUM> and plural capacitors <NUM> may be provided. Here, the capacitor <NUM>, the 3D sensor <NUM>, the resistance element <NUM>, the capacitor <NUM>, and the like other than the light source <NUM>, the PD <NUM>, and the drive unit <NUM> may be referred to as circuit components without being distinguished from one another.

The light source <NUM> and the PD <NUM> are provided on the base member <NUM>. The base member <NUM> is configured with an electrically insulating member. Further, the base member <NUM>, the drive unit <NUM>, the capacitor <NUM>, the resistor element <NUM>, and the capacitor <NUM> are provided on the wiring substrate <NUM>.

The light source <NUM> is configured as a light-emitting element array in which plural light-emitting elements are two-dimensionally arranged (see <FIG> to be described later). The light-emitting element is, for example, a vertical cavity surface emitting laser element (VCSEL). An example in which the light-emitting element is a vertical cavity surface emitting laser element (VCSEL) will be described in the following description. The vertical cavity surface emitting laser element (VCSEL) is referred to as a VCSEL. The light source <NUM> emits light in a direction perpendicular to a front surface of the wiring substrate <NUM> or the base member <NUM>. When performing three-dimensional sensing with a ToF method, the light source <NUM> is required to be driven by the drive unit <NUM> to emit pulsed light (hereinafter, referred to as an emitted light pulse) having, for example, <NUM> or more and a rise time of <NUM> ns or less. When face authentication is taken as an example, a distance of light radiation is about <NUM> to about <NUM>. A range in which a 3D shape of an object to be measured is measured is about <NUM> square. Therefore, the light source <NUM> is required to have a large output and efficiently dissipate heat generated by the light source <NUM>. A distance of light radiation is referred to as a measurement distance, and a range in which a 3D shape of an object to be measured is measured is referred to as a measurement range or a radiation range. A surface virtually provided in the measurement range or the radiation range is referred to as an irradiation surface.

The PD <NUM> is a photodiode of a pin-type or the like that outputs an electric signal corresponding to an amount of received light (hereinafter, referred to as a received light amount) and includes a p-type Si region serving as an anode, an i (intrinsic)-type Si region, and an n-type Si region serving as a cathode. An anode electrode is provided in the p-type Si region, and a cathode electrode is provided in the n-type Si region. The PD <NUM> is an example of a circuit element, the anode electrode is an example of a first electrode, and the cathode electrode is an example of a second electrode.

The light diffusing member <NUM> is provided so as to cover the light source <NUM> and the PD <NUM>. That is, the light diffusing member <NUM> is provided at a predetermined distance from the light source <NUM> and the PD <NUM> on the base member <NUM> by the holding portion <NUM> provided on the base member <NUM>. The light diffusing member <NUM> covering the light source <NUM> means that the light diffusing member <NUM> is provided on an emission path of light emitted from the light source <NUM> so that the light emitted from the light source <NUM> is transmitted through the light diffusing member <NUM>. This means a state in which the light source <NUM> and the PD <NUM> overlap the light diffusing member <NUM> in a plan view as will be described later. Here, the plan view refers to a view in a case of viewing in an x-y plane in <FIG>, (a) of <FIG>, and the like to be described later. The PD <NUM> is disposed at a position covered by the light diffusing member <NUM> so as to receive a part of light reflected by the light diffusing member <NUM> among light emitted from the light source <NUM>.

The holding portion <NUM> includes walls 61A, 61B, 62A, and 62B provided so as to surround the light source <NUM> and the PD <NUM>. Here, it is assumed that an outer shape of the base member <NUM>, an outer shape of the light diffusing member <NUM>, and an outer shape of the holding portion <NUM> are the same. Therefore, outer edges of the base member <NUM>, the light diffusing member <NUM>, and the holding portion <NUM> overlap one another. The outer shape of the base member <NUM> may be larger than the outer shape of the light diffusing member <NUM> or the outer shape of the holding portion <NUM>.

Details of the wiring substrate <NUM>, the base member <NUM>, the light source <NUM>, the light diffusing member <NUM>, the drive unit <NUM>, and the holding portion <NUM> in the light-emitting device <NUM> will be described later.

The 3D sensor <NUM> includes plural light receiving cells. For example, each light receiving cell is configured to receive pulsed reflected light (hereinafter, referred to as a received light pulse) from an object to be measured to which an emitted light pulse from the light source <NUM> is emitted, and accumulate electric charges corresponding to a time until the light receiving cell receives the pulsed reflected light for each light receiving cell. The 3D sensor <NUM> is configured as a device having a CMOS structure in which each light receiving cell includes two gates and two charge accumulating units corresponding to the gates. Then, generated photoelectrons are transferred to any one of the two charge accumulating units at high speed by alternately applying pulses to the two gates. Charges corresponding to a phase difference between the emitted light pulse and the received light pulse are accumulated in the two charge accumulating units. Then, the 3D sensor <NUM> outputs, as a signal, a digital value corresponding to the phase difference between the emitted light pulse and the received light pulse for each light receiving cell via an AD converter. That is, the 3D sensor <NUM> outputs a signal corresponding to a time from when light is emitted from the light source <NUM> to when the light is received by the 3D sensor <NUM>. The AD converter may be provided in the 3D sensor <NUM> or may be provided outside the 3D sensor <NUM>.

As described above, when face authentication is taken as an example, the light source <NUM> is required to emit light in an irradiation range of about <NUM> square at a distance of about <NUM> to about <NUM>. The 3D sensor <NUM> receives reflected light from the object to be measured to measure a 3D shape of the object to be measured. Therefore, the light source <NUM> is required to have a large output. Therefore, it is required to efficiently dissipate heat from the light source <NUM>.

The shape specifying unit <NUM> of the optical device control unit <NUM> acquires, from the 3D sensor <NUM>, the digital value obtained for each light receiving cell, and calculates a distance to the object to be measured for each light receiving cell. Further, the 3D shape of the object to be measured is specified based on the calculated distances.

The authentication processing unit <NUM> of the system control unit <NUM> performs authentication processing related to use of the information processing device <NUM> when the 3D shape of the object to be measured that is a specification result specified by the shape specifying unit <NUM> is a 3D shape stored in advance in the ROM or the like. The authentication processing related to use of the information processing device <NUM> is, for example, a processing of determining whether to permit the use of the information processing device <NUM> that is an own device. For example, when it is determined that a 3D shape of a face that is the object to be measured coincides with a face shape stored in a storage member such as the ROM, the use of the information processing device <NUM> including various applications provided by the information processing device <NUM> is permitted.

The shape specifying unit <NUM> and the authentication processing unit <NUM> are configured with, for example, a program. In addition, the shape specifying unit <NUM> and the authentication processing unit <NUM> may be configured with an integrated circuit such as an ASIC or an FPGA. Further, the shape specifying unit <NUM> and the authentication processing unit <NUM> may be configured with software such as a program and an integrated circuit such as an ASIC.

In <FIG>, the optical device <NUM>, the optical device control unit <NUM>, and the system control unit <NUM> are shown to be separated from each other. Alternatively, the system control unit <NUM> may include the optical device control unit <NUM>. The optical device control unit <NUM> may be included in the optical device <NUM>. Further, the optical device <NUM>, the optical device control unit <NUM>, and the system control unit <NUM> may be integrated.

Next, before describing the light-emitting device <NUM>, the light source <NUM>, the light diffusing member <NUM>, the drive unit <NUM>, and the capacitor <NUM> constituting the light-emitting device <NUM> will be described.

<FIG> is a plan view of the light source <NUM>. The light source <NUM> includes plural VCSELs arranged in a two-dimensional array. That is, the light source <NUM> is configured as a light-emitting element array in which a VCSEL serves as a light-emitting element array. A right direction of a paper surface is defined as an x direction, and an upper direction of the paper surface is defined as a y direction. A direction orthogonal to the x direction and the y direction in a counterclockwise manner is defined as a z direction. The x, y, and z directions in the drawings are the same. A front surface refers to a surface at a +z direction side, and a back surface refers to a surface at a -z direction side. The same applies to the other cases.

The VCSEL is a light-emitting element in which an active region serving as a light-emitting region is provided between a lower multilayer film reflector and an upper multilayer film reflector that are stacked on a semiconductor substrate <NUM> (see <FIG> to be described later), and laser light is emitted in a direction perpendicular to the semiconductor substrate <NUM>. Therefore, it is easy to form a two-dimensional array. The number of VCSELs included in the light source <NUM> is, for example, <NUM> to <NUM>. The plural VCSELs are connected to one another in parallel and are driven in parallel. The number of VCSELs described above is an example, and may be set according to a measurement distance or a measurement range.

An anode electrode <NUM> (see <FIG> to be described later) shared by the plural VCSELs is provided on a front surface of the light source <NUM>. A cathode electrode <NUM> is provided on a back surface of the light source <NUM> (see <FIG> to be described later). That is, the plural VCSELs are connected in parallel. When plural VCSELs are connected and driven in parallel, light having a strong intensity is simultaneously emitted and is radiated onto the object to be measured, as compared with a case where the VCSELs are individually driven.

Here, it is assumed that a planar shape of the light source <NUM>, which is a shape in a plan view, is a quadrangle. A side surface on a +y direction side is denoted as a side surface 21A, a side surface on a -y direction side is denoted as a side surface 21B, a side surface on a -x direction side is denoted as a side surface 22A, and a side surface on a +x direction side is denoted as a side surface 22B. The side surface 21A and the side surface 21B face each other. The side surface 22A and the side surface 22B are each continuous with the side surface 21A and the side surface 21B, and face each other. Here, the side surface 21A is an example of a first side surface, the side surface 21B is an example of a second side surface, the side surface 22A is an example of a third side surface, and the side surface 22B is an example of a fourth side surface.

<FIG> is a diagram illustrating a cross-sectional structure of one VCSEL in the light source <NUM>. The VCSEL is a VCSEL having a λ cavity structure. An upper direction of the paper surface is defined as a z direction.

The VCSEL is implemented by sequentially stacking, on the semiconductor substrate <NUM> such as an n-type GaAs substrate, an n-type lower distributed Bragg reflector (DBR) <NUM> in which AlGaAs layers having different Al compositions are alternately stacked, an active region <NUM> including a quantum well layer that is interposed between an upper spacer layer and a lower spacer layer, and a p-type upper distributed Bragg reflector <NUM> in which AlGaAs layers having different Al compositions are alternately stacked. Hereinafter, the distributed Bragg reflector is referred to as a DBR.

The n-type lower DBR <NUM> is a stacked body in which an Al<NUM>Ga<NUM>As layer and a GaAs layer are paired, and a thickness of each layer is λ/4nr (in which λ is an oscillation wavelength and nr is a refractive index of a medium), and these layers are alternately stacked in <NUM> cycles. A carrier concentration after doping with silicon that is an n-type impurity, is, for example, <NUM> × <NUM><NUM> cm-<NUM>.

The active region <NUM> is formed by stacking a lower spacer layer, a quantum well active layer, and an upper spacer layer. For example, the lower spacer layer is an undoped Al<NUM>Ga<NUM>As layer, the quantum well active layer is an undoped InGaAs quantum well layer and an undoped GaAs barrier layer, and the upper spacer layer is an undoped Al<NUM>Ga<NUM>As layer.

The p-type upper DBR <NUM> is a stacked body in which a p-type Al<NUM>Ga<NUM>As layer and a GaAs layer are paired, a thickness of each layer is λ/4nr, and these layers are alternately stacked in <NUM> cycles. A carrier concentration after doping with carbon that is a p-type impurity is, for example, <NUM> × <NUM><NUM> cm-<NUM>. Preferably, a contact layer formed of p-type GaAs is formed on an uppermost layer of the upper DBR <NUM>, and a current confinement layer <NUM> formed of p-type AlAs is formed to be a lowermost layer of the upper DBR <NUM> or inside the upper DBR <NUM>.

A cylindrical mesa M is formed on the semiconductor substrate <NUM> by etching stacked semiconductor layers from the upper DBR <NUM> to the lower DBR <NUM>. Accordingly, the current confinement layer <NUM> is exposed at a side surface of the mesa M. An oxidized region 210A oxidized from the side surface of the mesa M and a conductive region 210B surrounded by the oxidized region 210A are formed in the current confinement layer <NUM> by an oxidation process. In the oxidation process, an AlAs layer has a higher oxidation rate than an AlGaAs layer, and the oxidized region 210A is oxidized from the side surface of the mesa M toward an inner side at a substantially constant rate, so that a planar shape of the conductive region 210B is a shape that reflects an outer shape of the mesa M, that is, a circular shape, and a center of the conductive region 210B substantially coincides with an axial direction (dashed-dotted line) of the mesa M. The mesa M has a columnar structure in the present embodiment.

An annular p-side electrode <NUM> that is formed of metal and in which Ti/Au or the like is stacked is formed on an uppermost layer of the mesa M. The p-side electrode <NUM> is in ohmic contact with a contact layer of the upper DBR <NUM>. An inner side of the annular p-side electrode <NUM> defines a light emission port 212A through which laser light is emitted to an outside. That is, in the VCSEL, light is emitted in a direction perpendicular to the semiconductor substrate <NUM>, and the axial direction of the mesa M serves as an optical axis. Further, the cathode electrode <NUM> is formed on a back surface of the semiconductor substrate <NUM> as an n-side electrode. A front surface of the upper DBR <NUM> on the inner side of the p-side electrode <NUM> is a light-emitting surface. That is, an optical axis direction of the VCSEL is a light emitting direction.

An insulating layer <NUM> is provided in a manner of covering a front surface of the mesa M except for a portion of the p-side electrode <NUM> to which an anode electrode (the anode electrode <NUM> to be described later) is connected and the light emission port 212A. The anode electrode <NUM> is provided to be in ohmic contact with the p-side electrode <NUM> except for the light emission port 212A. The anode electrode <NUM> is shared by the plural VCSELs. That is, in the plural VCSELs constituting the light source <NUM>, the p-side electrodes <NUM> thereof are connected in parallel by the anode electrode <NUM>. The anode electrode <NUM> is an example of an upper surface electrode of the light-emitting element array.

The VCSEL may oscillate in a single transverse mode or in a multiple transverse mode. For example, an optical output of one VCSEL is <NUM> mW to <NUM> mW. Therefore, for example, when the light source <NUM> includes <NUM> VCSELs, an optical output of the light source <NUM> is 2W to 4W. In the light source <NUM> having such a large output, heat generated by the light source <NUM> is large.

<FIG> is a diagram illustrating an example of the light diffusing member <NUM>. (a) of <FIG> is a plan view and (b) of <FIG> is a cross-sectional view taken along a line VB-VB in (a) of <FIG>. In (a) of <FIG>, a right direction of a paper surface is defined as the x direction, an upper direction of the paper surface is defined as the y direction. A direction orthogonal to the x direction and the y direction in a counterclockwise manner is defined as the z direction. In (b) of <FIG>, a right direction of the paper surface is defined as the x direction, and an upper direction of the paper surface is defined as the z direction.

As illustrated in (b) of <FIG>, the light diffusing member <NUM> includes a resin layer <NUM> formed with unevenness for diffusing light onto a back surface of a flat glass base member <NUM> of which two surfaces are parallel to each other. The light diffusing member <NUM> further expands a spread angle of light incident from the VCSEL of the light source <NUM> and emits the light. That is, the unevenness formed in the resin layer <NUM> of the light diffusing member <NUM> refracts or scatters light to increase a spread angle α of incident light to a larger spread angle β of emitted light. That is, as illustrated in <FIG>, the spread angle β of light that is transmitted through the light diffusing member <NUM> and is emitted from the light diffusing member <NUM> is larger than the spread angle α of the light emitted from the VCSEL (α < β). Therefore, when the light diffusing member <NUM> is used, area of an irradiation surface irradiated with the light emitted from the light source <NUM> is increased as compared with a case where the light diffusing member <NUM> is not used. In addition, a light density on the irradiation surface is reduced. The light density refers to irradiance per unit area, and the spread angles α and β are full widths at half maximum (FWHM).

A planar shape of the light diffusing member <NUM> is, for example, a quadrangle. A width Wx of the light diffusing member <NUM> in the x direction and a vertical width Wy of the light diffusing member <NUM> in the y direction is <NUM> to <NUM>, and a thickness td of the light diffusing member <NUM> in the z direction is <NUM> to <NUM>. When the light diffusing member <NUM> has a size and a shape as described above, in particular, a light diffusing member suitable for face authentication of a portable information processing terminal or measurement at a relatively short distance of about several meters is provided. The planar shape of the light diffusing member <NUM> may be another shape such as a polygon or a circle.

When it is desired to drive the light source <NUM> at a higher speed, it is preferable to perform low-side driving. The low-side driving refers to a configuration in which a drive element such as an MOS transistor is positioned on a downstream side of a current path relative to a drive target such as a VCSEL. Conversely, a configuration in which a drive element is positioned on an upstream side is referred to as high-side driving.

<FIG> is a diagram illustrating an example of an equivalent circuit that drives the light source <NUM> by low-side driving. In <FIG>, the VCSEL of the light source <NUM>, the drive unit <NUM>, the capacitor <NUM>, a power supply <NUM>, the PD <NUM>, and a detection resistor element <NUM> that detects a current flowing through the PD <NUM> are illustrated.

The power supply <NUM> is provided in the optical device control unit <NUM> illustrated in <FIG>. The power supply <NUM> generates a direct current voltage having a positive side as a power supply potential and a negative side as a ground potential. The power supply potential is supplied to a power supply line <NUM>, and the ground potential is supplied to a ground line <NUM>.

As described above, the light source <NUM> is configured by connecting plural VCSELs in parallel. The anode electrode <NUM> (see <FIG>) of the VCSEL is connected to the power supply line <NUM>.

The drive unit <NUM> includes an n-channel MOS transistor <NUM> and a signal generation circuit <NUM> that turns on and turns off the MOS transistor <NUM>. A drain of the MOS transistor <NUM> is connected to the cathode electrode <NUM> (see <FIG>) of the VCSEL. A source of the MOS transistor <NUM> is connected to the ground line <NUM>. A gate of the MOS transistor <NUM> is connected to the signal generation circuit <NUM>. That is, the VCSEL and the MOS transistor <NUM> of the drive unit <NUM> are connected in series between the power supply line <NUM> and the ground line <NUM>. The signal generation circuit <NUM> generates an "H level" signal for setting the MOS transistor <NUM> to an ON state and an "L level" signal for setting the MOS transistor <NUM> to an OFF state under the control of the optical device control unit <NUM>.

The capacitor <NUM> has one terminal connected to the power supply line <NUM> and the other terminal connected to the ground line <NUM>. When there are plural capacitors <NUM>, the plural capacitors <NUM> are connected in parallel. The capacitor <NUM> is an electrolytic capacitor, a ceramic capacitor, or the like.

The PD <NUM> has a cathode electrode connected to the power supply line <NUM> and an anode electrode connected to one terminal of the detection resistor element <NUM>. The other terminal of the detection resistor element <NUM> is connected to the ground line <NUM>. That is, the PD <NUM> and the detection resistor element <NUM> are connected in series between the power supply line <NUM> and the ground line <NUM>. An output terminal <NUM>, which is a connection point between the PD <NUM> and the detection resistor element <NUM>, is connected to the optical device control unit <NUM>.

Next, a method of driving the light source <NUM> that is low-side driving will be described.

First, it is assumed that a signal generated by the signal generation circuit <NUM> in the drive unit <NUM> is at an "L level". In this case, the MOS transistor <NUM> is in an OFF state. That is, no current flows between the source and the drain of the MOS transistor <NUM>. Therefore, no current flows through the VCSEL connected in series with the MOS transistor <NUM>. The VCSEL does not emit light.

At this time, the capacitor <NUM> is charged by the power supply <NUM>. That is, one terminal of the capacitor <NUM> connected to the power supply line <NUM> is a power supply potential, and the other terminal of the capacitor <NUM> connected to the ground line <NUM> is a ground potential. The capacitor <NUM> accumulates electric charges determined by a capacitance, a power supply voltage (= power supply potential - ground potential), and time.

Next, when a signal generated by the signal generation circuit <NUM> in the drive unit <NUM> is at an "H level", the MOS transistor <NUM> shifts from an OFF state to an ON state. Then, the electric charges accumulated in the capacitor <NUM> are discharged, and a current flows through the MOS transistor <NUM> and the VCSEL that are connected in series, so that the VCSEL emits light.

When a signal generated by the signal generation circuit <NUM> in the drive unit <NUM> is at an "L level", the MOS transistor <NUM> shifts from an ON state to an OFF state. Accordingly, the VCSEL stops emitting light. Then, the power supply <NUM> resumes the accumulation of electric charges in the capacitor <NUM>.

As described above, each time when the signal output from the signal generation circuit <NUM> shifts between the "L level" and the "H level", the MOS transistor <NUM> is repeatedly turned on and turned off, and emission of light and non-emission of light that is a state in which the VCSEL stops emitting light are repeated. That is, a light pulse is emitted from the VCSEL. Repetition of ON and OFF of the MOS transistor <NUM> may be referred to as switching. Here, as illustrated in the equivalent circuit of <FIG>, a current path to the light source <NUM>, which includes the light source <NUM>, the MOS transistor <NUM>, the capacitor <NUM>, and the like, is referred to as a circuit or a circuit for driving the light source <NUM>.

Although charges (a current) may be directly supplied from the power supply <NUM> to the VCSEL without providing the capacitor <NUM>, the electric charges are accumulated in the capacitor <NUM>, and the accumulated charges are discharged when the MOS transistor <NUM> is switched from an OFF state to an ON state to rapidly supply a current to the VCSEL, so that a rise time of light emission of the VCSEL is reduced.

The PD <NUM> is connected in a reverse direction between the power supply line <NUM> and the ground line <NUM> via the detection resistor element <NUM>. Therefore, no current flows in a state where light is not radiated. As described above, when the PD <NUM> receives a part of light reflected by the light diffusing member <NUM> among the light emitted from the VCSEL, a current corresponding to a received light amount flows through the PD <NUM>. Therefore, the current flowing through the PD <NUM> is measured as a voltage of the output terminal <NUM>, and a light intensity of the light source <NUM> is detected. Therefore, the optical device control unit <NUM> controls the light intensity of the light source <NUM> to be a predetermined light intensity based on the received light amount of the PD <NUM>. For example, when the light intensity of the light source <NUM> is lower than the predetermined light intensity, the optical device control unit <NUM> increases the power supply potential of the power supply <NUM> to increase an amount of electric charges accumulated in the capacitor <NUM>, thereby increasing a current flowing through the VCSEL. On the other hand, when the light intensity of the light source <NUM> is higher than the predetermined light intensity, the power supply potential of the power supply <NUM> is lowered to reduce the amount of electric charges accumulated in the capacitor <NUM>, thereby reducing the current flowing through the VCSEL. In this way, the light intensity of the light source <NUM> is controlled.

In addition, when the received light amount of the PD <NUM> is extremely low, the light diffusing member <NUM> may be detached or damaged, and the light emitted from the light source <NUM> may be directly irradiated to the outside. In such a case, the light intensity of the light source <NUM> is suppressed by the optical device control unit <NUM>. For example, emission of light from the light source <NUM>, that is, radiation of light onto an object to be measured, is stopped.

As described above, the PD <NUM> is provided to detect the light intensity of the light source <NUM>. Therefore, as the PD <NUM> is disposed farther from the light source <NUM>, a received light amount thereof decreases, and detection sensitivity of the light intensity of the light source <NUM> decreases. Therefore, the PD <NUM> may be disposed close to the light source <NUM>. That is, the PD <NUM> is an example of a circuit element expected to be disposed close to the light source <NUM>. In addition, if the PD <NUM> is disposed close to the light source <NUM>, area of the light diffusing member <NUM> can be reduced. That is, the expensive light diffusing member <NUM> is reduced in size, and the light-emitting device <NUM> becomes inexpensive.

Next, the light-emitting device <NUM> will be described in detail.

<FIG> is a diagram illustrating the light-emitting device <NUM> to which the first embodiment of the invention is applied. (a) of <FIG> is a plan view, (b) of <FIG> is a cross-sectional view taken along a line VIIB-VIIB in (a) of <FIG>, and (c) of <FIG> is a cross-sectional view taken along a line VIIC-VIIC in (a) of <FIG>. In (a) of <FIG>, a right direction of a paper surface is defined as the x direction, an upper direction of the paper surface is defined as the y direction. A direction orthogonal to the x direction and the y direction in a counterclockwise manner is defined as the z direction. Therefore, in (b) and (c) of <FIG>, a right direction of the paper surface is defined as the x direction, and an upper direction of the paper is defined as the z direction. The same applies to similar drawings to be described below.

As illustrated in (b) and (c) of <FIG>, the base member <NUM> and the drive unit <NUM> are provided on the wiring substrate <NUM> in the light-emitting device <NUM>. The light source <NUM>, the PD <NUM>, and the holding portion <NUM> are provided on the base member <NUM>. The light diffusing member <NUM> is provided on the holding portion <NUM>. As illustrated in (a) and (c) of <FIG>, the light source <NUM> and the PD <NUM> are covered by the light diffusing member <NUM>. Therefore, a part of light reflected by a back surface of the light diffusing member <NUM> among the light emitted from the light source <NUM> is received by the PD <NUM>. The holding portion <NUM> may be provided on the wiring substrate <NUM>.

As illustrated in (a) of <FIG>, in the light-emitting device <NUM>, the light source <NUM>, the PD <NUM>, and the drive unit <NUM> are linearly arranged in the x direction. In the light-emitting device <NUM>, even in a configuration in which the PD <NUM> is disposed between the light source <NUM> and the drive unit <NUM> and the PD <NUM> is disposed close to the light source <NUM>, a path of a wiring pattern (a light-source cathode wiring pattern <NUM> to be described later) connecting the light source <NUM> and the drive unit <NUM> is not restricted by the PD <NUM>.

That is, in the light-emitting device <NUM>, the light source <NUM> and the PD <NUM> are mounted on the base member <NUM> provided with a wiring pattern, and the base member <NUM> is mounted on the wiring substrate <NUM> provided with a wiring pattern for connecting to the drive unit <NUM>, and thus the path of the wiring pattern connecting the light source <NUM> and the drive unit <NUM> is not restricted by the PD <NUM> thanks to three-dimensional intersection of the wiring patterns.

The wiring substrate <NUM> is, for example, a three-layer multilayer substrate. That is, the wiring substrate <NUM> includes a first conductive layer, a second conductive layer, and a third conductive layer from a side where the base member, the drive unit <NUM>, and the like are mounted. Further, an insulating layer is provided between the first conductive layer and the second conductive layer, and between the second conductive layer and the third conductive layer. For example, the third conductive layer is the power supply line <NUM>, and the second conductive layer is the ground line <NUM>. A light-source anode wiring pattern <NUM> that constitutes a part of a current path to the light source <NUM>, the light-source cathode wiring pattern <NUM>, a PD anode wiring pattern <NUM> that constitutes a part of a current path to the PD <NUM>, and a PD cathode wiring pattern <NUM> are formed by the first conductive layer. Further, wiring patterns to which circuit components such as the capacitor <NUM>, the resistor element <NUM>, and the capacitor <NUM> are connected are formed by the first conductive layer, and these wiring patterns are not illustrated. In this manner, the wiring substrate <NUM> is a multilayer substrate, the power supply line <NUM> is the third conductive layer, and the ground line <NUM> is the second conductive layer, so that a fluctuation in the power supply potential and the ground potential is easily suppressed. A path through which a current flows, such as the light-source anode wiring pattern <NUM>, the light-source cathode wiring pattern <NUM>, the PD anode wiring pattern <NUM>, and the PD cathode wiring pattern <NUM>, is referred to as a wiring pattern. A wiring pattern formed by the first conductive layer, and the second conductive layer or the third conductive layer are electrically connected to each other via a via. For example, the via is a conductive portion formed by embedding a conductive material in a hole provided in a manner of penetrating the wiring substrate <NUM> in a thickness direction thereof.

The first conductive layer, the second conductive layer, and the third conductive layer are formed of a metal such as copper (Cu) or silver (Ag) or a conductive material such as a conductive paste containing these metals. The insulating layer is formed of epoxy resin, ceramic, or the like.

The base member <NUM> is formed of an electrically insulating material. Since the light source <NUM> is provided on the base member <NUM>, the base member <NUM> may be formed of a heat dissipation member that has an electrically insulating property and a higher thermal conductivity higher than the wiring substrate <NUM>. Examples of the heat dissipation member that has an electrically insulating property include ceramics such as silicon nitride and aluminum nitride. When the base member <NUM> is a heat dissipation member, heat generated by the light source <NUM> is easily transferred to the holding portion <NUM> and the light diffusion member <NUM> via the base member <NUM> and dissipated, and heat dissipation efficiency is improved.

A light-source anode wiring pattern 111F that constitutes a part of a current path to the light source <NUM>, a light-source cathode wiring pattern 112F, a PD anode wiring pattern 113F that constitutes a part of a current path to the PD <NUM>, and a PD cathode wiring pattern 114F are provided on a front surface of the base member <NUM>. A light-source anode wiring pattern 111B that constitutes a part of a current path to the light source <NUM>, a light-source cathode wiring pattern 112B, a PD anode wiring pattern 113B that constitutes a part of a current path to the PD <NUM>, and a PD cathode wiring pattern 114B are provided on a back surface of the base member <NUM> (see <FIG> to be described later). Wiring patterns, which are denoted by the same number and are on the front surface and the back surface of the base member <NUM>, are connected to each other by a via. For example, as illustrated in (b) of <FIG>, the light-source anode wiring pattern 111F provided on the front surface and the light-source anode wiring pattern 111B provided on the back surface are connected by a via 111V. The via is denoted by adding "V" to a reference number of a wiring pattern. Here, the via is, for example, a conductive portion formed by embedding a conductive material in a hole that is provided in a manner of penetrating the base member <NUM>, and the via electrically connects wiring patterns on the front surface and wiring patterns on the back surface. Inductance of a circuit is reduced by connecting the wiring patterns using plural vias.

The light-source cathode wiring pattern 112F of the base member <NUM> and the cathode electrode <NUM> (see <FIG>) of the light source <NUM> are connected by a conductive adhesive or the like. The light-source anode wiring pattern 111F of the base member <NUM> and the anode electrode <NUM> (see <FIG>) of the light source <NUM> are connected to each other by bonding wires 23A, 23B, and 23C on the side surfaces 21A, 21B, and 22A side of the light source <NUM>. Here, the light-source anode wiring pattern 111F is provided on the side surfaces 21A, 21B, and 22A side of the light source <NUM>, and is not provided on the side surface 22B side of the light source <NUM>. In this manner, the bonding wire connecting the anode electrode <NUM> and the light-source anode wiring pattern 111F is not provided on the side surface 22B side of the light source <NUM>. Therefore, the PD <NUM>, which is an example of a circuit element desired to be disposed close to the light source <NUM>, is disposed close to the light source <NUM>.

In the above description, the anode electrode <NUM> of the light source <NUM> and the light-source anode wiring pattern 111F are connected to each other on the three side surface (side surfaces 21A, 21B, and 22A) sides of the light source <NUM> by the bonding wires (bonding wires 23A, 23B, and 23C). The anode electrode <NUM> of the light source <NUM> and the light-source anode wiring pattern 111F may be connected to each other by a bonding wire on at least two side surface sides of the light source <NUM>. As compared with a case where the anode electrode <NUM> of the light source <NUM> and the light-source anode wiring pattern 111F are connected by a bonding wire on two side surface sides, the inductance of the circuit is reduced in the case where the anode electrode <NUM> of the light source <NUM> and the light-source anode wiring pattern 111F are connected on three side surface sides. The anode electrode <NUM> of the light source <NUM> and the light-source anode wiring pattern 111F may be connected to each other by a bonding wire on two side surface (side surfaces 21A and 21B) sides, and another circuit element may be provided on the base member <NUM> on the third side surface (side surface 22A) side. The other circuit element is, for example, a temperature sensor. By providing the other circuit element, the inductance of the circuit can be reduced.

In the PD <NUM>, a cathode electrode of the PD <NUM> is bonded to the PD cathode wiring pattern 114F of the base member <NUM> by a conductive adhesive, and an anode electrode of the PD <NUM> is connected to the PD anode wiring pattern 113F of the base member <NUM> by a bonding wire 23D.

The light-source anode wiring pattern <NUM> and the light-source cathode wiring pattern <NUM> that are provided on the wiring substrate <NUM> are respectively connected to the light-source anode wiring pattern 111B and the light-source cathode wiring pattern 112B on the back surface of the base member <NUM>. Similarly, the PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> that are provided on the wiring substrate <NUM> are respectively connected to the PD anode wiring pattern 113B and the PD cathode wiring pattern 114B on the back surface of the base member <NUM>. The wiring patterns of the wiring substrate <NUM> and the wiring patterns of the base member <NUM> are connected by a conductive adhesive or the like.

As illustrated in (b) of <FIG>, in the cross-sectional view taken along the line VIIB-VIIB shifted to the -y direction side from a center in the y direction, the light-source anode wiring pattern <NUM> of the wiring substrate <NUM> and the light-source anode wiring pattern 111B on the back surface of the base member <NUM> are connected to each other. The light-source anode wiring pattern 111B of the base member <NUM> is connected to the light-source anode wiring pattern 111F on the front surface of the base member <NUM> via the via 111V. The light-source anode wiring pattern 111F of the base member <NUM> is connected to the anode electrode <NUM> (see <FIG>) of the light source <NUM> via the bonding wires 23A, 23B, and 23C.

Similarly, the PD cathode wiring pattern <NUM> of the wiring substrate <NUM> is connected to the PD cathode wiring pattern 114B provided on the back surface of the base member <NUM>. The PD cathode wiring pattern 114B of the base member <NUM> is connected to the PD cathode wiring pattern 114F provided on the front surface of the base member <NUM> via a via 114V. The PD cathode wiring pattern 114F of the base member <NUM> is connected to the cathode electrode of the PD <NUM>.

That is, in the cross section taken along the line VIIB-VIIB, the light-source anode wiring pattern <NUM> of the wiring substrate <NUM>, the light-source anode wiring pattern 111B on the back surface of the base member <NUM>, and the light-source anode wiring pattern 111F on the front surface of the base member <NUM> are provided in a manner of facing one another. Similarly, the PD cathode wiring pattern <NUM> of the wiring substrate <NUM>, the PD cathode wiring pattern 114B provided on the back surface of the base member <NUM>, and the PD cathode wiring pattern 114F provided on the front surface of the base member <NUM> are provided in a manner of facing one another.

On the other hand, as illustrated in (c) of <FIG>, in the cross-sectional view taken along the line VIIC-VIIC in a central portion in the y direction, the light-source cathode wiring pattern <NUM> of the wiring substrate <NUM> is provided in a manner of extending from a lower side of the light source <NUM> to the drive unit <NUM>. The light-source anode wiring pattern <NUM> of the wiring substrate <NUM> is connected to the light-source anode wiring pattern 111B provided on the back surface of the base member <NUM>, and the light-source cathode wiring pattern <NUM> is connected to the light-source cathode wiring pattern 112B provided on the back surface of the base member <NUM>. The light-source anode wiring pattern 111B of the base member <NUM> is connected to the light-source anode wiring pattern 111F provided on the front surface of the base member <NUM> via the via 111V, and the light-source cathode wiring pattern 112B is connected to the light-source cathode wiring pattern 112F provided on the front surface of the base member <NUM> via a via 112V The light-source cathode wiring pattern 112F is connected to the cathode electrode <NUM> of the light source <NUM>.

However, in the VIIC-VIIC cross section illustrated in (c) of <FIG>, the PD cathode wiring pattern 114F on the base member <NUM> is not connected to the light-source cathode wiring pattern <NUM> provided on the wiring substrate <NUM>.

That is, in the cross section taken along the line VIIC-VIIC, the light-source anode wiring pattern <NUM> of the wiring substrate <NUM>, the light-source anode wiring pattern 111B on the back surface of the base member <NUM>, and the light-source anode wiring pattern 111F on the front surface of the base member <NUM> are provided in a manner of facing one another. However, although the light-source cathode wiring pattern 112B on the back surface of the base member <NUM> and the light-source cathode wiring pattern 112F on the front surface of the base member <NUM> are provided in a manner of facing each other, the light-source cathode wiring pattern <NUM> of the wiring substrate <NUM> is provided in a manner of extending from a portion facing the light-source cathode wiring pattern 112B to the drive unit <NUM>. In addition, a wiring pattern facing the PD cathode wiring pattern 114F on the base member <NUM> is not provided on the back surface of the base member <NUM>. That is, the PD cathode wiring pattern 114F on the base member <NUM> and the light-source cathode wiring pattern <NUM> provided on the wiring substrate <NUM> intersect three-dimensionally with each other but are not electrically connected to each other. That is, the base member <NUM> is provided across the light-source cathode wiring pattern <NUM>. In this way, the light-source cathode wiring pattern <NUM> of the wiring substrate <NUM> is provided to extend from the light source <NUM> to the drive unit <NUM> at the back surface of the base member <NUM>, and the PD <NUM> is provided in a region on the base member <NUM>, which is a region overlapping the light-source cathode wiring pattern <NUM> in a plan view. When the base member <NUM> is not provided across the light-source cathode wiring pattern <NUM>, and the base member <NUM> is provided at one side in a width direction of the light-source cathode wiring pattern <NUM>, a size of the light-emitting device <NUM> increases.

As described above, as illustrated in (a) of <FIG>, in the light-emitting device <NUM> to which the first embodiment is applied, even in the configuration in which the PD <NUM> is disposed close to the light source <NUM> and the PD <NUM> is disposed between the light source <NUM> and the drive unit <NUM>, the wiring pattern (here, the light-source cathode wiring pattern <NUM>) connecting the light source <NUM> and the drive unit <NUM> is linearly provided. Accordingly, the wiring pattern (here, the light-source cathode wiring pattern <NUM>) connecting the light source <NUM> and the drive unit <NUM> is shortened, and an increase in inductance of the circuit is suppressed. That is, a path of a wiring pattern connecting the light source <NUM> and the drive unit <NUM> is not restricted by the PD <NUM>.

Next, the wiring patterns provided on the wiring substrate <NUM> and the base member <NUM> will be described in detail.

<FIG> is a diagram illustrating the wiring patterns provided on the wiring substrate <NUM> and the base member <NUM>. (a) of <FIG> shows a front surface of the wiring substrate <NUM>, (b) of <FIG> shows the front surface of the base member <NUM>, and (c) of <FIG> shows the back surface of the base member <NUM>. (a) of <FIG> shows a wiring pattern formed by the first conductive layer of the wiring substrate <NUM>, and does not show a wiring pattern formed by the second conductive layer that is the ground line <NUM> and a wiring pattern formed by the third conductive layer that is the power supply line <NUM>. The second conductive layer and the third conductive layer are solid films without a portion where a via used to connect to the wiring pattern formed by the first conductive layer is provided.

On the front surface of the wiring substrate <NUM> illustrated in (a) of <FIG>, the light-source anode wiring pattern <NUM> and the light-source cathode wiring pattern <NUM> are provided. The light-source cathode wiring pattern <NUM> has a quadrangular planar shape. The light-source anode wiring pattern <NUM> is provided adjacent to a short side of the light-source cathode wiring pattern <NUM> on the -x direction side, and extends along two long sides connected to the short side. Further, on the front surface of the wiring substrate <NUM>, the PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> are provided. The PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> are provided so as to sandwich the light-source cathode wiring pattern <NUM> from the ± y direction.

On the front surface of the base member <NUM> illustrated in (b) of <FIG>, the light-source anode wiring pattern 111F and the light-source cathode wiring pattern 112F are provided. The light-source cathode wiring pattern 112F has a quadrangular planar shape corresponding to the planar shape of the light source <NUM> illustrated in <FIG>. The light-source anode wiring pattern 111F is provided adjacent to three sides of the light-source cathode wiring pattern 112F. Further, on the front surface of the base member <NUM>, the PD anode wiring pattern 113F and the PD cathode wiring pattern 114F are provided.

On the back surface of the base member <NUM> illustrated in (c) of <FIG>, the light-source anode wiring pattern 111B connected to the light-source anode wiring pattern 111F via the via 111V, the light-source cathode wiring pattern 112B connected to the light-source cathode wiring pattern 112F via the via 112V, the PD anode wiring pattern 113B connected to the PD anode wiring pattern 113F via a via 113V, and the PD cathode wiring pattern 114B connected to the PD cathode wiring pattern 114F via the via 114V are provided. In the base member <NUM>, the wiring patterns on the front surface shown in (b) of <FIG> and the wiring patterns on the back surface shown in (c) of <FIG> are mirror-inverted except for the PD anode wiring pattern 113F and the PD anode wiring pattern 113B. That is, the wiring patterns on the front surface and the wiring patterns on the back surface, of the base member <NUM>, are provided in a manner of overlapping one another in a plan view. The light-source cathode wiring pattern <NUM> is a wiring pattern on the wiring substrate <NUM> that is connected to the light source <NUM> and extends from the back surface side of the base member <NUM> to the drive unit <NUM>.

On the other hand, with respect to the PD anode wiring pattern 113F and the PD anode wiring pattern 113B, the PD anode wiring pattern 113F on the front surface has a longer length in the y direction than the PD anode wiring pattern 113B on the back surface, and extends to a central portion in the y direction of the base member <NUM>.

When the base member <NUM> is disposed at a portion indicated by a surrounding broken line of the wiring substrate <NUM> in (a) of <FIG>, the light-source anode wiring pattern <NUM> of the wiring substrate <NUM> and the light-source anode wiring pattern 111B of the base member <NUM> are connected, and the light-source cathode wiring pattern <NUM> of the wiring substrate <NUM> and the light-source cathode wiring pattern 112B of the base member <NUM> are connected. Similarly, the PD anode wiring pattern <NUM> of the wiring substrate <NUM> is connected to the PD anode wiring pattern 113B of the base member <NUM>, and the PD cathode wiring pattern <NUM> of the wiring substrate <NUM> is connected to the PD cathode wiring pattern 114B of the base member <NUM>.

At this time, if the PD cathode wiring pattern 114B on the back surface has the same shape as the PD cathode wiring pattern 114F on the front surface in the base member <NUM>, the PD cathode wiring pattern 114B short-circuits the light-source cathode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> of the wiring substrate <NUM>. Therefore, in the base member <NUM>, a length in the +y direction of the PD cathode wiring pattern 114B on the back surface is made shorter than that of the PD cathode wiring pattern 114F on the front surface, and the PD cathode wiring pattern 114B does not short-circuit the light-source cathode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> of the wiring substrate <NUM>. That is, in order to dispose the PD <NUM> between the light source <NUM> and the drive unit <NUM>, the PD cathode wiring pattern 114F connected to the cathode electrode of the PD <NUM> is provided on the base member <NUM>, so that the PD <NUM> three-dimensionally intersects with the light-source cathode wiring pattern <NUM> provided on the wiring substrate <NUM> without being short-circuited.

Before the base member <NUM> is disposed on the wiring substrate <NUM>, the light source <NUM> and the PD <NUM> are mounted on the base member <NUM>. That is, the cathode electrode <NUM> (see <FIG>) of the light source <NUM> is bonded onto the light-source cathode wiring pattern 112F of the base member <NUM> by a conductive adhesive or the like. The anode electrode <NUM> (see <FIG>) of the light source <NUM> and the light-source anode wiring pattern 111F are connected by the bonding wires 23A, 23B, and 23C.

Further, the cathode electrode of the PD <NUM> is bonded onto the PD cathode wiring pattern 114F of the base member <NUM> by a conductive adhesive, and the anode electrode of the PD <NUM> is connected to the PD anode wiring pattern 113F of the base member <NUM> by the bonding wire 23D.

As described above, in the light-emitting device <NUM> of the first embodiment, by using the base member <NUM>, even in the configuration in which the PD <NUM> is disposed between the light source <NUM> and the drive unit <NUM>, the path of the wiring pattern connecting the light source <NUM> and the drive unit <NUM> is not restricted by the PD <NUM>. Accordingly, an increase in inductance of the circuit is suppressed.

As described above, the anode electrode and the cathode electrode of the PD <NUM> are separated on two sides to sandwich the light-source cathode wiring pattern <NUM> provided on the wiring substrate <NUM>, and are connected to the PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM>. That is, the PD <NUM> is connected to the wiring substrate <NUM> on outer sides such that the light-source cathode wiring pattern <NUM> is sandwiched.

<FIG> is a diagram illustrating a relationship in which the PD <NUM> is provided at an outer side of the light-source cathode wiring pattern <NUM> in the wiring substrate <NUM>. (a) of <FIG> is a first example and (b) of <FIG> is a second example.

The first example illustrated in (a) of <FIG> is the same as that illustrated in <FIG>. In the first example, the light-source cathode wiring pattern <NUM> linearly connects the light source <NUM> and the drive unit <NUM>. The light-source cathode wiring pattern <NUM> is formed to have a quadrangular planar shape. That is, even when the PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> for connecting the PD <NUM> are provided, the light-source cathode wiring pattern <NUM> is provided with the same line width without being affected by the PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM>. Therefore, with the light-source cathode wiring pattern <NUM>, the light source <NUM> and the drive unit <NUM> are linearly provided at a shortest distance, an increase in inductance of the circuit is suppressed. Resistance of the light-source cathode wiring pattern <NUM> is smaller than that of the second example to be described below.

In the second example illustrated in (b) of <FIG>, in order to provide the PD <NUM>, the light-source cathode wiring pattern <NUM> is provided so as to be narrowed at portions where the PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> are provided. Therefore, the resistance of the light-source cathode wiring pattern <NUM> is larger than that of the first example. However, also in the second example, the light source <NUM> and the drive unit <NUM> are linearly provided at a shortest distance. That is, the light-source cathode wiring pattern <NUM> is less likely to be affected by the provision of the PD <NUM>. The light-source cathode wiring pattern <NUM> may be configured as described above.

As described above, since the PD <NUM> is connected to the wiring substrate <NUM> on the outer sides such that the light-source cathode wiring pattern <NUM> is sandwiched from both sides, a path of the light-source cathode wiring pattern <NUM> is not affected as compared with a case where the PD <NUM> is provided on an inner side of a light-source cathode wiring pattern <NUM>' shown in a light-emitting device <NUM>-<NUM> of a second comparative example described later. Therefore, an increase in inductance of the circuit is suppressed. The PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> are an example of a connection portion of the PD <NUM>, which is an example of a circuit element, with the wiring substrate <NUM>, and the anode electrode of the PD <NUM> is an example of a first electrode and the cathode electrode thereof is an example of a second electrode.

In the light-emitting device <NUM> of the first embodiment, the base member <NUM> is used. Hereinafter, a light-emitting device in which the base member <NUM> is not used will be described as a comparative example.

<FIG> is a diagram illustrating a light-emitting device <NUM>-<NUM> of a first comparative example, not part of the claimed invention. (a) of <FIG> is a plan view, and (b) of <FIG> is a cross-sectional view taken along a line XB-XB in (a) of <FIG>. The light-emitting device <NUM>-<NUM> does not use the base member <NUM> used in the light-emitting device <NUM>. That is, in the light-emitting device <NUM>-<NUM>, the light source <NUM>, the PD <NUM>, the drive unit <NUM>, and other circuit components are provided on the wiring substrate <NUM>.

In the light-emitting device <NUM>-<NUM> of the first comparative example, as illustrated in (a) of <FIG>, the PD <NUM>, the light source <NUM>, and the drive unit <NUM> are arranged along the x direction of the wiring substrate <NUM>. Therefore, on the side surface 22B side of the light source <NUM>, the light source <NUM> and the drive unit <NUM> are connected by the light-source cathode wiring pattern <NUM>. Therefore, as illustrated in (a) and (b) of <FIG>, the light-source cathode wiring pattern <NUM> is set between the light source <NUM> and the drive unit <NUM> without being affected by the PD <NUM>.

On the other hand, the PD <NUM> has to be disposed on a side surface side other than the side surface 22B side of the light source <NUM> on which the light-source cathode wiring pattern <NUM> is provided, that is, on the side surfaces 21A, 21B, 22A side. However, the light-source anode wiring pattern <NUM> is provided on the side surfaces 21A, 21B, and 22A side. The light-source anode wiring pattern <NUM> and the anode electrode <NUM> of the light source <NUM> are connected by the bonding wires 23A, 23B, and 23C. For this reason, the PD <NUM> has to be disposed at an outer side of the light-source anode wiring pattern <NUM>, which is a -x side, and the light source <NUM> and the PD <NUM> are not disposed close to each other.

<FIG> is a diagram illustrating the light-emitting device <NUM>-<NUM> of the second comparative example, not part of the claimed invention. (a) of <FIG> is a plan view, and (b) of <FIG> is a cross-sectional view taken along a line XIB-XIB in (a) of <FIG>. The light-emitting device <NUM>-<NUM> does not use the base member <NUM> used in the light-emitting device <NUM>. That is, in the light-emitting device <NUM>-<NUM>, the light source <NUM>, the PD <NUM>, the drive unit <NUM>, and other circuit components are provided on the wiring substrate <NUM>.

In the light-emitting device <NUM>-<NUM> of the second comparative example, as illustrated in (b) of <FIG>, the light source <NUM>, the PD <NUM>, and the drive unit <NUM> are linearly arranged in the x direction of the wiring substrate <NUM>. That is, the PD <NUM> is disposed between the light source <NUM> and the drive unit <NUM>. Similarly to the light-emitting device <NUM>-<NUM>, the light-source anode wiring pattern <NUM> is provided on the side surfaces 21A, 21B, and 22A side of the light source <NUM>, and the light-source anode wiring pattern <NUM> and the light-source anode electrode <NUM> of the light source <NUM> are connected by the bonding wires 23A, 23B, and 23C. The PD <NUM> is provided on the side surface 22B side where the light-source anode wiring pattern <NUM> is not provided. Therefore, the PD <NUM> desired to be provided close to the light source <NUM> is disposed close to the light source <NUM>.

On the other hand, the light-source cathode wiring pattern <NUM>' is provided to be branched so as to include the PD <NUM> on an inner side. That is, the light-source cathode wiring pattern <NUM>' has to be provided so as to bypass the PD <NUM>. As described above, in the light-emitting device <NUM>-<NUM>, the light-source cathode wiring pattern <NUM>' connecting the light source <NUM> and the drive unit <NUM> is affected by arrangement of the PD <NUM>, and inductance of the circuit increases.

As described above, by providing the base member <NUM> as in the light-emitting device <NUM> to which the first embodiment is applied, the path of the wiring pattern (here, the light-source cathode wiring pattern <NUM>) connecting the light source <NUM> and the drive unit <NUM> is not restricted by the PD <NUM> even in a configuration in which a circuit element (here, the PD <NUM> as an example) desired to be provided close to the light source <NUM> is disposed between the light source <NUM> and the drive unit <NUM>.

In the light-emitting device <NUM> to which the first embodiment of the invention is applied, the PD <NUM> desired to be disposed close to the light source <NUM> is provided on the base member <NUM>. In a light-emitting device 4A to which the second embodiment of the invention is applied, as to be described later, the light source <NUM> is not provided on a base member <NUM>.

<FIG> is a diagram illustrating the light-emitting device 4A to which the second embodiment of the invention is applied. (a) of <FIG> is a plan view, (b) of <FIG> is a cross-sectional view taken along a line XIIB-XIIB in (a) of <FIG> of <FIG> is a cross-sectional view taken along a line XIIC-XIIC in (a) of <FIG>. The same components as those of the light-emitting device <NUM> are denoted by the same reference signs, and a description thereof will be omitted.

As illustrated in (b) and (c) of <FIG>, in the light-emitting device 4A, the light source <NUM>, the base member <NUM>, the drive unit <NUM>, and the holding portion <NUM> are provided on the wiring substrate <NUM>. The PD <NUM> is provided on the base member <NUM>. In the light-emitting device 4A, the holding portion <NUM> is provided on the wiring substrate <NUM>, and the light diffusing member <NUM> is held by the holding portion <NUM>. Here, the base member <NUM> may be formed of an electrically insulating material. The wiring substrate <NUM> on which the light source <NUM> is provided may be a heat dissipation substrate having a thermal conductivity higher than the base member <NUM>.

As illustrated in (a) of <FIG>, in the light-emitting device 4A, the light source <NUM>, the PD <NUM>, and the drive unit <NUM> are linearly arranged in the x direction. In the light-emitting device 4A, even in a configuration in which the PD <NUM> is disposed between the light source <NUM> and the drive unit <NUM> and the PD <NUM> is disposed close to the light source <NUM>, a path of a wiring pattern (a light-source cathode wiring pattern <NUM> to be described later) connecting the light source <NUM> and the drive unit <NUM> is not restricted by the PD <NUM>.

A light-source anode wiring pattern 11A that constitutes a part of a current path to the light source <NUM>, the light-source cathode wiring pattern <NUM>, a PD anode wiring pattern <NUM> that constitutes a part of a current path to the PD <NUM>, and a PD cathode wiring pattern <NUM> are formed by a first conductive layer of the wiring substrate <NUM>. In (a) of <FIG>, the PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> are not illustrated due to being on a back surface side of the base member <NUM>. The light-source anode wiring pattern 11A is narrower than the light-source anode wiring pattern <NUM> shown in (a) of <FIG>.

On a front surface of the base member <NUM>, a PD anode wiring pattern 115F and a PD cathode wiring pattern 116F that constitute a part of a current path to the PD <NUM> are provided. On a back surface of the base member <NUM>, a PD anode wiring pattern 115B and a PD cathode wiring pattern 116B that constitute a part of a current path to the PD <NUM> are also provided (see <FIG> to be described later). Wiring patterns, which are denoted by the same number and are on the front surface and the back surface of the base member <NUM>, are connected to each other by a via.

The light-source cathode wiring pattern <NUM> of the wiring substrate <NUM> and the cathode electrode <NUM> (see <FIG>) of the light source <NUM> are bonded to each other by a conductive adhesive or the like. The light-source anode wiring pattern 11A of the wiring substrate <NUM> and the anode electrode <NUM> (see <FIG>) of the light source <NUM> are connected to each other by the bonding wires 23A, 23B, and 23C on the side surfaces 21A, 21B, and 22A side of the light source <NUM>. Here, the light-source anode wiring pattern 11A is provided on the side surfaces 21A, 21B, and 22A side of the light source <NUM>, and is not provided on the side surface 22B side of the light source <NUM>. In this manner, the bonding wire connecting the anode electrode <NUM> and the light-source anode wiring pattern 11A is not provided on the side surface 22B side of the light source <NUM>. Therefore, the PD <NUM>, which is an example of a circuit element desired to be disposed close to the light source <NUM>, is disposed close to the light source <NUM>.

In the PD <NUM>, a cathode electrode of the PD <NUM> is bonded onto the PD cathode wiring pattern 116F of the base member <NUM> by a conductive adhesive, and an anode electrode of the PD <NUM> is connected to the PD anode wiring pattern 115F of the base member <NUM> by the bonding wire 23D.

The PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> that are provided on the wiring substrate <NUM> are connected to the PD anode wiring pattern 115B and the PD cathode wiring pattern 116B on the back surface of the base member <NUM>, respectively.

As illustrated in (b) of <FIG>, in the cross-sectional view taken along the line XIIB-XIIB shifted from a center in the y direction to the -y direction side, the PD cathode wiring pattern <NUM> of the wiring substrate <NUM> and the PD cathode wiring pattern 116B on the back surface of the base member <NUM> are connected to each other. The PD cathode wiring pattern 116B of the base member <NUM> is connected to the PD cathode wiring pattern 116F on the front surface of the base member <NUM> via a via 116V. The PD cathode wiring pattern 116F of the base member <NUM> is connected to the cathode electrode of the PD <NUM>.

That is, in the cross section taken along the line XIIB-XIIB, the PD cathode wiring pattern <NUM> of the wiring substrate <NUM>, the PD cathode wiring pattern 116B on the back surface of the base member <NUM>, and the PD cathode wiring pattern 116F on the front surface of the base member <NUM> are provided in a manner of facing one another.

On the other hand, as illustrated in (c) of <FIG>, in the cross-sectional view taken along the line XIIC-XIIC of a central portion in the y direction, the PD cathode wiring pattern 116F on the base member <NUM> is not connected to the light-source cathode wiring pattern <NUM> provided on the wiring substrate <NUM>.

That is, in the cross section taken along the line XIIC-XIIC, the light-source cathode wiring pattern <NUM> of the wiring substrate <NUM> is provided in a manner of extending from the light source <NUM> to the drive unit <NUM>. On the wiring substrate <NUM>, a wiring pattern facing the PD cathode wiring pattern 116F on the base member <NUM> is not provided. In this way, the PD cathode wiring pattern 116F on the base member <NUM> and the light-source cathode wiring pattern <NUM> provided on the wiring substrate <NUM> intersect with each other three-dimensionally but are not electrically connected to each other.

Next, the wiring patterns provided on the wiring substrate <NUM> and the base member <NUM> will be described.

<FIG> is a diagram illustrating the wiring patterns provided on the wiring substrate <NUM> and the base member <NUM>. (a) of <FIG> shows a front surface of the wiring substrate <NUM>, (b) of <FIG> shows the front surface of the base member <NUM>, and (c) of <FIG> shows the back surface of the base member <NUM>. (a) of <FIG> illustrates a wiring pattern formed by the first conductive layer of the wiring substrate <NUM>.

On the front surface of the wiring substrate <NUM> illustrated in (a) of <FIG>, the light-source anode wiring pattern 11A and the light-source cathode wiring pattern <NUM> are provided. The light-source cathode wiring pattern <NUM> is the same as the light-source cathode wiring pattern <NUM> illustrated in (a) of <FIG>, and thus is denoted by the same reference sign. On the front surface of the wiring substrate <NUM>, the PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> are provided. The PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> have a shorter length in the y direction than the PD anode wiring pattern <NUM> and the PD cathode wiring pattern <NUM> that are illustrated in (a) of <FIG>.

Similar to the PD anode wiring patterns 113F and 113B and the PD cathode wiring patterns 114F and 114B of the base member <NUM> illustrated in (b) and (c) of <FIG>, the base member <NUM> illustrated in (b) and (c) of <FIG> is provided with the PD anode wiring pattern 115F and the PD cathode wiring pattern 116F on the front surface thereof and the PD anode wiring pattern 115B and the PD cathode wiring pattern 116B on the back surface thereof. The PD anode wiring pattern 115F on the front surface and the PD anode wiring pattern 115B on the back surface have the same planar shape, and are mirror-inverted on the front and back surfaces of the base member <NUM>. On the other hand, the PD cathode wiring pattern 116F on the front surface has a longer length in the y direction than the PD cathode wiring pattern 116B on the back surface, and extends to a central portion in the y direction of the base member <NUM>. The PD anode wiring pattern 115F on the front surface and the PD anode wiring pattern 115B on the back surface as well as the PD cathode wiring pattern 116F on the front surface and the PD cathode wiring pattern 116B on the back surface are connected by vias provided in a manner of penetrating the base member <NUM>.

When the base member <NUM> is disposed at a portion indicated by a surrounding broken line of the wiring substrate <NUM> in (a) of <FIG>, the PD anode wiring pattern <NUM> of the wiring substrate <NUM> and the PD anode wiring pattern 115B of the base member <NUM> are connected, and the PD cathode wiring pattern <NUM> of the wiring substrate <NUM> and the PD cathode wiring pattern 116B of the base member <NUM> are connected.

At this time, in the base member <NUM>, the PD cathode wiring pattern 116B on the back surface has a shape different from the PD cathode wiring pattern 116F on the front surface, and the light-source cathode wiring pattern <NUM> of the wiring substrate <NUM> and the PD cathode wiring pattern <NUM> are not short-circuited. That is, in order to dispose the PD <NUM> at a central portion of the wiring substrate <NUM> in the y direction, the PD cathode wiring pattern 116F connected to the cathode electrode of the PD <NUM> is provided on the base member <NUM>, so that the PD <NUM> three-dimensionally intersects with the light-source cathode wiring pattern <NUM> provided on the wiring substrate <NUM> without being short-circuited. That is, the base member <NUM> is provided across the light-source cathode wiring pattern <NUM>. In this way, the light-source cathode wiring pattern <NUM> of the wiring substrate <NUM> is provided to extend from the light source <NUM> to the drive unit <NUM> at the back surface of the base member <NUM>, and the PD <NUM> is provided in a region on the base member <NUM>, which is a region overlapping the light-source cathode wiring pattern <NUM> in a plan view. The light-source cathode wiring pattern <NUM> is a wiring pattern on the wiring substrate <NUM> that is connected to the light source <NUM> and extends from the back surface side of the base member <NUM> to the drive unit <NUM>.

Before disposing the base member <NUM> on the wiring substrate <NUM>, the PD <NUM> is mounted on the base member <NUM>. On the other hand, on the wiring substrate <NUM>, the cathode electrode <NUM> of the light source <NUM> is bonded to the light-source cathode wiring pattern <NUM> by a conductive adhesive. The base member <NUM> on which the PD <NUM> is mounted is mounted on the wiring substrate <NUM>. Next, the anode electrode <NUM> of the light source <NUM> is connected to the light-source anode wiring pattern <NUM> by the bonding wires 23A, 23B, and 23C, and the anode electrode of the PD <NUM> is connected to the PD anode wiring pattern 115F on the base member <NUM> by the bonding wire 23D.

As described above, by providing the base member <NUM> in the light-emitting device 4A of the second embodiment, the path of the wiring pattern (here, the light-source cathode wiring pattern <NUM>) connecting the light source <NUM> and the drive unit <NUM> is not restricted by the PD <NUM> even in a configuration in which a circuit element (here, the PD <NUM> as an example) desired to be provided close to the light source <NUM> is disposed between the light source <NUM> and the drive unit <NUM>. Accordingly, an increase in inductance of the circuit is suppressed.

In the first embodiment and the second embodiment described above, a light receiving element (PD40) for monitoring a light amount has been described as an example of a circuit element, and alternatively another circuit component such as a capacitor (capacitor <NUM>) that supplies a current to the light source <NUM> may be described as a circuit element.

Although the light diffusing member <NUM> is used in the first embodiment and the second embodiment, the present invention may be applied to a configuration that includes, instead of the light diffusing member <NUM>, a member that transmits light, for example, a transparent base member such as a protective cover, and an optical member such as a condensing lens or a microlens array.

Claim 1:
A light-emitting device (<NUM>) comprising:
a wiring substrate (<NUM>);
a base member (<NUM>) that is mounted on the wiring substrate (<NUM>);
a light source (<NUM>) that is mounted on a front surface of the base member (<NUM>);
a drive unit (<NUM>) that is mounted on the wiring substrate and drives the light source (<NUM>);
a wiring pattern (<NUM>) that is on the wiring substrate (<NUM>), is connected to the light source (<NUM>) and extends from a back surface side of the base member (<NUM>) toward the drive unit (<NUM>); and
a circuit element (<NUM>) that is provided in a region on the front surface of the base member (<NUM>) between the light source (<NUM>) and the drive unit (<NUM>), the region overlapping the wiring pattern (<NUM>) in a plan view, so that a path of the wiring pattern (<NUM>) connecting the light source (<NUM>) and the drive unit (<NUM>) is not restricted by the circuit element (<NUM>).