JP5169417B2 - Lighting device, display device, finder device, and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact illuminating device with less optical loss, as well as a display or the like having the illuminating device. <P>SOLUTION: The illuminating device includes a transparent substrate 54 having an incident face 60 for light L2 to enter and an emission face 66 emitting at least part of the incident light. The transparent substrate has a paraboloid 62 reflecting at least part of the light incident from the incident face into the transparent substrate as a parallel light and guiding it to the emission face. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a lighting device and the like, and more particularly, to a lighting device and the like suitable for being provided in a finder device or the like.

  Some finder devices provided in cameras and the like include an in-finder display device. As an illuminating device used for such an in-finder display device, a device capable of obtaining a parallel light beam is preferable. As an illuminating device that can obtain a parallel light beam, for example, a device in which a stereoscopic projection lens group and a parabolic mirror are arranged so that their focal points coincide with each other is known (see Patent Document 1).

However, in the illumination device according to the related art, when the light emitted from the light source is to be efficiently guided, the parabolic mirror tends to increase in size, and it is difficult to reduce the size of the illumination device. Further, since the optical path is configured by combining a plurality of optical members including a stereoscopic projection lens group and a parabolic mirror, there is a problem that the structure becomes complicated.
JP-A-5-333269

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a small-sized lighting device with little light loss, a display device including the lighting device, and the like.

In order to solve the above-described problem, a lighting device according to the present invention includes:
A transparent substrate (54) having an incident surface (60) on which light (L2) is incident and an exit surface (66) from which at least a part of the incident light is emitted;
The transparent substrate has a parabolic surface (62) that reflects at least part of light incident on the transparent substrate from the incident surface into parallel light and guides the light to the exit surface.

  For example, the incident surface and the paraboloid may be arranged on the side surface (58) of the transparent substrate.

  Further, for example, light incident from the incident surface is repeatedly reflected by the main surface (56) intersecting the side surface, and travels from the incident surface to the paraboloid and from the paraboloid to the exit surface. May be.

  Further, for example, in the illumination device according to the present invention, a total reflection surface that totally reflects the light may be disposed on the main surface that intersects the side surface of the transparent substrate.

  For example, the said output surface may be arrange | positioned at the said side surface of the said transparent substrate.

Further, for example, the emission surface is disposed on a main surface intersecting the side surface of the transparent substrate,
A reflection surface (64) that reflects at least a part of the light reflected by the paraboloid toward the emission surface may be disposed on a side surface of the transparent substrate.

  Further, for example, the reflection surface may have a predetermined angle of inclination with respect to the main surface intersecting with the side surface, greater than 0 degrees and less than 90 degrees.

  For example, the illuminating device which concerns on this invention may have the light source (52) arrange | positioned at the focus of the said paraboloid (62).

  Further, for example, in the lighting device according to the present invention, the paraboloid may be provided so that light reflected by the paraboloid does not face the direction of the light source.

  For example, the incident surface may be disposed between the light source and the paraboloid.

  In addition, for example, in the lighting device according to the present invention, a metal film for improving reflectance may be provided on the paraboloid of the transparent substrate.

A display device according to the present invention includes any one of the illumination devices described above.
Moreover, the finder apparatus which concerns on this invention has said illuminating device.
In addition, a camera according to the present invention includes the above finder device.

  In the above description, in order to explain the present invention in an easy-to-understand manner, the description is made in association with the reference numerals of the drawings showing the embodiments. However, the present invention is not limited to this. The configuration of the embodiment described later may be improved as appropriate, or at least a part of the configuration may be replaced with another component. Further, the configuration requirements that are not particularly limited with respect to the arrangement are not limited to the arrangement disclosed in the embodiment, and can be arranged at a position where the function can be achieved.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a schematic view of a camera including an illumination device according to an embodiment of the present invention.
2 is an enlarged plan view of a display device included in the camera shown in FIG.
3 is a cross-sectional view of a main part of the display device shown in FIG.
4 is a perspective view of a lighting device provided in the display device shown in FIG. 2 and FIG.
FIG. 5 is a schematic diagram showing the progress of illumination light mainly in the direction along the main surface of the transparent substrate in the illumination device shown in FIG.
FIG. 6 is a view of the illumination device shown in FIG. 4 as viewed from the side, and is a schematic diagram illustrating illumination light that travels while being totally reflected by the main surface of the transparent substrate.
FIG. 7 is a plan view of an essential part of the illumination device shown in FIG. 4 viewed from the main surface side.
FIG. 8 is a plan view of a display device including an illumination device according to the second embodiment of the present invention.
FIG. 9 is a perspective view of the illumination device shown in FIG.
First embodiment

  As shown in FIG. 1, a single-lens reflex camera 2 according to an embodiment of the present invention has a camera body 4, and a lens barrel 8 having a photographing lens 6 is attached to the camera body 4 in a replaceable manner. Yes. The single-lens reflex camera 2 may be a film camera using a silver salt film as the recording medium 9 or a single-lens reflex digital camera using an image sensor such as a CCD or CMOS as the recording medium 9.

  A quick return mirror 10 is disposed between the photographing lens 6 and the recording medium 9 to reflect the photographing light L1 from the subject 14 to the finder optical system. Although not shown, a shutter is provided between the recording medium 9 and the quick return mirror 10.

  A finder screen 12 is disposed at a position optically conjugate with the image forming surface of the recording medium 9, and the photographing light L <b> 1 from the subject 14 is reflected by the quick return mirror 10 to form an image on the finder screen 12. To do. A subject image formed on the finder screen 12 can be observed by a person looking through the finder through the pentaprism 16 and the eyepiece 18.

  At the time of shooting, the quick return mirror 10 is moved from the optical path of the shooting light L1 to the outside of the optical path, and a subject image is formed on the recording medium 9. In the description of each embodiment, the X axis, the Y axis, and the Z axis are defined as shown in FIG. That is, the direction in which the photographing light L1 is directed from the photographing lens 6 to the recording medium 9 is the positive direction of the X axis, and the direction in which the photographing light L1 is directed from the quick return mirror 10 to the pentaprism 16 is the positive direction of the Z axis, the X axis and the Z axis. The direction perpendicular to is the Y axis.

  A finder device is built in the camera body 4. The viewfinder device includes a viewfinder screen 12, a pentaprism 16, an eyepiece lens 18, and a display device 20. The display device 20 includes a display element 21 disposed between the finder screen 12 and the pentaprism 16 and an illumination device 22 attached to the display element 21.

  In the present embodiment, a diffractive optical element having a display unit using a refractive index type diffraction grating is used as the display element 21. However, the display element 21 used in the display device 20 is not limited to this, and a transmissive liquid crystal display element or a polymer dispersed liquid crystal display element may be used. In FIG. 1, illumination light L <b> 2 that has entered the display element 21 from the illumination device 22 is converted into a pentaprism by a refractive index type diffraction grating in accordance with control by a drive unit 50 connected to the display element 21 via a wiring 48. Diffracted in 16 directions.

  As shown in FIG. 2, the display element 21 displays predetermined information, for example, a mark such as a focus detection area, in the finder field by the display unit 32 configured by a refractive index type diffraction grating. The illumination light L2 emitted from the display element 21 in the finder apparatus is reflected by the pentaprism 16 shown in FIG. 1 and is observed as predetermined information by the photographer via the eyepiece 18. As a result, predetermined information is superimposed on the above-described subject image and displayed in the viewfinder field, and the photographer can observe the subject image and the predetermined information at the same time, thereby realizing a so-called superimpose display.

  As shown in FIG. 2, the display device 20 according to this embodiment includes a rectangular flat plate-shaped display element 21 and an illumination attached to the X-axis positive direction side short side surface 21 a of the rectangular flat plate-shaped display element 21. Device 22. FIG. 3 is a cross-sectional view of an essential part taken along line III-III of the display device 20 shown in FIG. 2, and schematically shows the internal structure of the display element 21.

  As shown in FIG. 3, the display element 21 includes a transparent first substrate 24a and a second substrate 24b. An optical material layer 26 is formed between the first substrate 24a and the second substrate 24b. The optical material layer 26 is sealed with a transparent sealing material 28 connected so as to seal the outer peripheral edge portions of the first and second substrates 24a and 24b.

  In the optical material layer 26, the display portion 32 sandwiched between the transparent electrodes 36 and 38 is a portion that is a liquid crystal hologram. The display unit 32 forms a striped layer structure in which the refractive index isotropic region 40 and the refractive index anisotropic region 42 are alternately repeated. The refractive index isotropic region 40 and the refractive index anisotropic region 42 are alternately repeated in the direction along the plane of the display element 21 and in the traveling direction of the illumination light L2 from the illumination device 22. A non-display part 34 is formed around the display part 32.

  When no voltage is applied to the transparent electrodes 36 and 38, the refractive index of the liquid crystal and the refractive index of the polymer are different from each other so as to satisfy the Bragg diffraction condition for the illumination light L2 incident from the illumination device 22. It is designed to take a rate value. That is, in a state where no voltage is applied, a refractive index type diffraction grating in which layers having a high refractive index and layers having a low refractive index are alternately arranged is formed on the display unit 32. The diffraction condition at this time is that the illumination light L2 entering the optical material layer 26 through the short side surface 21a of the display element 21 and traveling inside the optical material layer 26 is diffracted in the display unit 32, and the illumination light L2 is shown in FIG. Is set to be diffracted in the direction of the pentaprism 16 shown in FIG.

  On the other hand, when a voltage is applied to the transparent electrodes 36 and 38, the orientation of the liquid crystal in the refractive index anisotropy region 42 changes and the refractive index also changes, and the refractive index of the liquid crystal becomes the refractive index of the polymer. Will be equal. As a result, the illumination light L2 emitted from the illumination device 22 and entering the optical material layer 26 and traveling in the negative direction of the X axis passes through the display unit 32 without being diffracted by the display unit 32.

  As described above, the control unit that controls the display device 20 can switch between display and non-display of the display unit 32 of the display element 21 by switching between application and non-application of the voltage to the transparent electrodes 36 and 38. .

  FIG. 4 is a perspective view of the illumination device 22 provided in the display device 20 shown in FIGS. 2 and 3. The illumination device 22 has a light source 52 and a transparent substrate 54. As the light source 52, a point light source such as LE or LED, a surface light source, a volume light source, or the like can be used. The transparent substrate 54 is mainly made of a transparent material such as glass or resin, and the illumination light generated by the light source 52 can be emitted after being converted into a substantially parallel light beam and incident on the display element 21.

  The transparent substrate 54 includes two main surfaces 56 that are substantially parallel to the YZ plane passing through the X axis and the Z axis, and a side surface 58 that intersects the two main surfaces 56 and connects the two main surfaces 56. Have. Further, the transparent substrate 54 according to the present embodiment has an incident surface 60, a paraboloid 62, a reflecting surface 64, and an exit surface 66. As shown in FIG. 4, the entrance surface 60, the paraboloid 62, and the reflection surface 64 are disposed on the side surface 58 of the transparent substrate 54, and the exit surface 66 is disposed on the main surface 56 of the transparent substrate 54.

  From the incident surface 60 of the transparent substrate 54 shown in FIG. 5, the illumination light L <b> 2 generated by the light source 52 enters the inside of the transparent substrate 54. The illumination light L2 incident from the incident surface 60 travels inside the transparent substrate 54 toward the parabolic surface 62. At this time, the illumination light L2 that has entered the inside of the transparent substrate 54 travels toward the paraboloid 62 while being repeatedly reflected by the main surface 56, as shown in FIG.

Of the illumination light L2 traveling inside the transparent substrate 54, illumination light L2a and L2b having incident angles θa and θb (incident angles of the illumination light L2 with respect to the principal surface 56) shown in FIG. The condition of total reflection in is generally expressed by the following equation (1).
θa, θb> sin ⁻¹ (1 / n1) (1)
Here, n1 is the refractive index of the transparent substrate 54.

  In the present embodiment, the refractive index n1 of the transparent substrate 54 is preferably 1.47 or more. As the refractive index n1 of the transparent substrate 54 is larger, the illumination light L2 having smaller incident angles θa and θb can be totally reflected on the main surface 56. Thus, the main surface 56 becomes a total reflection surface that totally reflects the illumination light L2, thereby effectively suppressing light loss that occurs when the illumination light L2 travels toward the paraboloid 62. Can do. Further, in the transparent substrate 54 according to the present embodiment, the incident surface 60 is disposed so as to be close to the light source 52, and the illumination light L2 incident from the incident surface 60 is guided to the paraboloid 62 while totally reflecting. Therefore, although the transparent substrate 54 is small in size, the illumination light L2 generated by the light source 52 can be efficiently guided to the inside of the transparent substrate 54 and can be guided while suppressing light loss.

  The paraboloid 62 shown in FIG. 5 reflects the illumination light L2 incident on the inside of the transparent substrate 54 as parallel light. In this embodiment, the paraboloid 62 constitutes a paraboloid with the light source 52 as a focal point when observed from the normal direction (X-axis direction) of the main surface 56 as shown in FIG. Therefore, the illumination light L2 incident on the transparent substrate 54 from the incident surface 60 is directed to the direction D1 connecting the apex P1 of the paraboloid 62 and the light source 52 disposed at the focal point of the paraboloid 62 by the paraboloid 62. And reflected in a substantially parallel direction.

  Thus, when observed from the normal direction (X-axis direction) of the main surface 56, the paraboloid 62 is parallel to the direction D1 and the illumination light L2 incident on the inside of the transparent substrate 54 from the incident surface 60. Reflect with light. A vapor deposition film made of silver, aluminum, other metals, or the like may be formed on the parabolic surface 62 of the transparent substrate 54 in order to improve the reflectance of the illumination light L2. In the present embodiment, since the paraboloid 62 shown in FIG. 7 does not include the apex P1 of the paraboloid 62, the light source 52 passes through the transmission path of the illumination light L2 from the paraboloid 62 to the emission surface 66. There is no interference. Therefore, in the illuminating device 22 according to the present embodiment, a phenomenon in which the intensity distribution of the illumination light L2 on the emission surface 66 is not uniform due to the shadow of the light source 52 is prevented.

  The illumination light L2 reflected by the paraboloid 62 proceeds toward the reflection surface 64 while being repeatedly reflected by the main surface 56 as in the illumination lights L2a and L2b shown in FIG. 6B (FIG. 5). . The conditions under which the illumination lights L2a and L2b are totally reflected at the main surface 56 are the same as when the illumination lights L2a and L2b travel from the incident surface 60 toward the paraboloid 62 (FIG. 6A). .

  The reflecting surface 64 shown in FIGS. 5 and 6 reflects the illumination light L2, L2a, L2b reflected by the paraboloid 62 toward the emission surface 66. The reflecting surface 64 in the present embodiment preferably has an inclination of a predetermined angle θ1 with respect to the main surface 56 that is greater than 0 degree and smaller than 90 degrees. By setting the angle θ1 between the reflecting surface 64 and the main surface 56 within an appropriate range, the traveling direction of the illumination light L2 and the incident angle of the illumination light L2 with respect to the emission surface 66 are adjusted, and the illumination light L2 is emitted. The light can be efficiently emitted from the surface 66.

  Similarly to the parabolic surface 62, a vapor deposition film made of silver, aluminum, other metals, or the like may be formed on the reflective surface 64 in order to improve the reflectance of the illumination light L2. Note that the portion of the transparent substrate 54 where the reflection surface 64 and the emission surface 66 are disposed may be formed of another member having a different refractive index from the other portions of the transparent substrate 54.

  5 and 6 emits the illumination light L2 reflected by the paraboloid 62, the reflecting surface 64, and the like. In the present embodiment, the light emitting surface 66 is attached so that the short side surface 21a of the display element 21 is in close contact therewith. Therefore, the illumination light L2 emitted from the emission surface 66 immediately enters the display element 21 and travels through the optical material layer 26 shown in FIG. The display device 20 shown in FIGS. 1 and 2 performs superimpose display by diffracting the illumination light L2 incident on the optical material layer 26.

  Note that the exit surface 66 of the transparent substrate 54 shown in FIG. 3 can be configured to have a predetermined inclination with respect to the main surface 56. By tilting the emission surface 66 with respect to the main surface 56, the emission direction of the illumination light L2 can be adjusted, and the mounting angle between the transparent substrate 54 and the display element 21 can be adjusted.

  The illumination device 22 according to the present embodiment has a transparent surface having an incident surface 60 on which the illumination light L2 is incident, a paraboloid 62 that reflects the illumination light L2 as parallel light, and an exit surface 66 that emits the illumination light L2. A substrate 54 is included. Therefore, the illumination device 22 according to the present embodiment can change the illumination light L2 generated by the light source 52 into a directional light beam, and at the same time, until the illumination light L2 is emitted from the illumination device 22. The optical loss that occurs can be suppressed. That is, the illuminating device 22 according to the present embodiment can emit the illumination light L2 generated by the light source 52 as a directional light beam such as parallel light without significant loss.

  Further, the transparent substrate 54 has both a function of making the illumination light L2 generated by the light source 52 into parallel light and a function of guiding and emitting to the exit surface which is arranged at a predetermined position and has a predetermined area. This is realized with one optical member. Therefore, the illumination device according to the present embodiment has a simple structure as compared with the prior art that realizes both functions, and can be downsized. In the present embodiment, since the incident surface 60 of the transparent substrate 54 is provided between the light source 52 and the paraboloid 62, a mirror other than the transparent substrate 54 or There is no need to provide a lens or the like, and the lighting device 22 can be further downsized.

  In the illumination device 22 according to the present embodiment, the incident surface 60 and the paraboloid 62 of the transparent substrate 54 intersect the main surface 56 arranged along the main transmission direction (YZ plane direction) of the illumination light L2. Therefore, it is easy to reduce the thickness. Further, the illumination light L 2 travels inside the transparent substrate 54 while being totally reflected by the main surface 56 inside the transparent substrate 54. Therefore, the illuminating device according to the present embodiment can effectively suppress light loss that occurs between the time when the illumination light L2 is generated by the light source 52 and is emitted from the emission surface 66.

Furthermore, in the illuminating device 22 according to the present embodiment, since the reflecting surface 64 is disposed on the side surface 58 of the transparent substrate 54, the illumination light L <b> 2 is emitted from the emission surface 66 disposed on the main surface 56 that intersects the side surface 58. Can be emitted. At this time, the illumination light L2 can be efficiently emitted from the emission surface 66 by setting the angle θ1 between the reflection surface 64 and the main surface 56 to a predetermined angle greater than 0 degree and less than 90 degrees. .
Second embodiment

  FIG. 8 is a plan view of a display device 20a having an illumination device 22a according to the second embodiment of the present invention. The illumination device 22a according to the second embodiment is the first except that the emission surface 66a is disposed on the side surface 58 of the transparent substrate 54a and does not have the reflection surface 64 corresponding to the reflection surface 64 in the first embodiment. It is the same as that of the illuminating device 22 which concerns on embodiment. In addition, regarding the illuminating device 22a according to the second embodiment and the display device 20a having the illuminating device 22a, description of the same parts as those in the first embodiment will be omitted.

  In the illumination device 22a according to the second embodiment, the entrance surface 60, the paraboloid 62, and the exit surface 66a are all disposed on the side surface 58 of the transparent substrate 54a. Accordingly, the main traveling direction of the illumination light L2 inside the illumination device 22a and the main traveling direction of the illumination light L2 inside the display element 21 are both in the direction along the XY plane and coincide with each other. The whole can be thinned.

  Moreover, as shown in FIG. 9, since the illuminating device 22a which concerns on 2nd Embodiment does not have the reflective surface 64 in the illuminating device 22 in 1st Embodiment, its structure is simpler. Note that, in the transparent substrate 54a, the illumination light L2 travels inside the transparent substrate while being totally reflected by the main surface 56, as in the illumination device 22 according to the first embodiment.

As described above, the display device 20a having the illumination device 22a according to the second embodiment has the effect that the display device 20 can be thinned in addition to the effect of the display device 20 having the illumination device 22 according to the first embodiment. Have
Other embodiments

  In the first and second embodiments described above, the illumination devices 22 and 22a are described as examples applied to the display device 20 provided in the camera, but the application of the illumination device according to the present invention is not limited to this. For example, the illuminating device of the present invention may be used as an illuminating device such as a backlight of an LCD or a display provided in a mobile phone by taking advantage of its small size, low light loss and energy saving.

FIG. 1 is a schematic view of a camera including an illumination device according to an embodiment of the present invention. FIG. 2 is an enlarged plan view of the display device included in the camera shown in FIG. 3 is a cross-sectional view of a main part of the display device shown in FIG. FIG. 4 is a perspective view of a lighting device provided in the display device shown in FIGS. 2 and 3. FIG. 5 is a schematic diagram showing the progress of illumination light mainly in the direction along the main surface of the transparent substrate in the illumination device shown in FIG. FIG. 6 is a diagram of the illumination device shown in FIG. 4 as viewed from the side, and is a schematic diagram illustrating illumination light that travels while being totally reflected by the main surface of the transparent substrate. FIG. 7 is a plan view of the main part of the illumination device shown in FIG. 4 as viewed from the main surface side. FIG. 8 is a plan view of a display device including an illumination device according to the second embodiment of the present invention. FIG. 9 is a perspective view of the illumination device shown in FIG.

Explanation of symbols

2 ... Single-lens reflex camera 20 ... Display device 21 ... Display element 22, 22a ... Illumination device 52 ... Light source 54 ... Transparent substrate 56 ... Main surface 58 ... Side surface 60 ... Incident surface 62 ... Parabolic surface 64 ... Reflective surface 66 ... Outgoing surface L2 ... Subject light

Claims (13)

A transparent substrate having an incident surface on which light is incident and an exit surface from which at least part of the incident light is emitted;
The transparent substrate, said at least a portion of the light incident into the transparent substrate from the incident surface is reflected in the parallel light, have a parabolic leading to the exit face,
The incident surface and the parabolic surface are disposed on a side surface of the transparent substrate,
The illumination apparatus according to claim 1, wherein the incident surface is disposed closer to the exit surface than the parabolic surface . The lighting device according to claim 1 ,
The light incident from the incident surface is repeatedly reflected on a main surface intersecting with the side surface, and travels between the paraboloid from the incident surface and between the paraboloid and the exit surface. . The lighting device according to claim 1 or 2 ,
Lighting device total reflection surface for totally reflecting the light, characterized in that arranged on the main surface you intersects with the side surface of the transparent substrate. It is the illuminating device described in any one of Claims 1-3 ,
The illumination device according to claim 1, wherein the emission surface is disposed on the side surface of the transparent substrate. It is the illuminating device described in any one of Claims 1-3 ,
The exit surface is disposed on a main surface intersecting the side surface of the transparent substrate,
At least a part of the light reflected by the parabolic, lighting apparatus reflecting surface for reflecting toward the exit surface, characterized in that it is arranged on the side surface of the transparent substrate. The lighting device according to claim 5 ,
The reflective surface, the lighting apparatus characterized by having a predetermined angle of inclination the less greater than 90 degrees above 0 degrees to the main surface intersecting with the side surface. It is the illuminating device described in any one of Claims 1-6 ,
A lighting device having a light source disposed at a focal point of the paraboloid. A lighting device according to any one of claims 1 to 7,
The parabolic surface is provided so that the light reflected by the parabolic surface does not go in the direction of the light source. It is an illuminating device described in any one of Claims 1-8 ,
The illumination apparatus according to claim 1, wherein the incident surface is disposed between the light source and the paraboloid. The illumination device according to any one of claims 1 to 9 ,
An illumination device, wherein a metal film for improving reflectivity is provided on the paraboloid of the transparent substrate. The display apparatus which has an illuminating device of any one of Claim 1- Claim 10 . A viewfinder device comprising the display device according to claim 11 . A camera comprising the finder device according to claim 12 .

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