JP2016167425A - Luminaire and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminaire capable of evenly illuminating the inside of an annular light guide body, and a display device including the luminaire.SOLUTION: A luminaire includes a light source, and a light guide body having a continuously annular shape. The light source is arranged so that light from the light source is made incident to the inside from a light incident structure provided in the light guide body. The light guide body has such a shape that part of light, made incident from the light incident structure, is totally reflected on the surface of the light guide body to guide light, and the other part of light is extracted from the inner peripheral surface of the annular shape of the light guide body to the outside of the light guide body.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a lighting device and a display device.

  Non-light-emitting displays such as electrophoretic displays, electrochromic displays, and reflective liquid crystal displays have low power consumption and are used as display devices for wristwatches and portable electronic devices. However, in an environment where there is no illumination light such as at night or in a dark room, it is difficult to see the display, so it is necessary to provide an auxiliary illumination device.

  As an illumination device, there is a front light structure that illuminates a reflective display element from an observer side. In the front light structure, a light emitting structure is formed on the surface of the light guide plate arranged so as to cover the display area of the display element, and the light propagating through the light guide plate is taken out to the display element side by the light emitting structure, and the display element is removed. Illuminate.

  However, covering the display area with a light guide plate having a light emitting structure formed on the surface of the display element has a problem that the contrast of display is lowered regardless of whether or not the lighting device is turned on.

  A front light having a configuration in which a light guide is not disposed on a display area of a display element is disclosed in Patent Document 1. In Patent Document 1, an annular light guide is arranged around a display area, light from a light emitting diode is introduced into the light guide, and the display area is illuminated by a light extraction structure formed in the light guide. It is.

However, when light from a light emitting diode, which can be regarded as a point light source, is introduced into the light guide, the light intensity in the vicinity of the light emitting diode is strong. There is a problem that it is difficult to illuminate uniformly.
In addition, since the light extraction structure is a discrete structure, there is a problem that the amount of emitted light becomes discrete and it is difficult to uniformly illuminate the entire display region.

  Patent Documents 1 and 2 disclose an illumination device for room illumination that includes an annular light guide plate.

JP 2012-0669504 A JP, 2014-041801, A

  The illumination devices described in Patent Documents 1 and 2 are configured to emit light in the normal direction of the light guide plate, and are not for emitting light toward the central opening. Since the opening is provided in the light guide, the problem that the display area of the display element is covered with the light guide can be avoided, but the display area exposed from the opening of the light guide cannot be illuminated.

  The present invention has been made in view of the above-described problems of the prior art, and provides an illumination device that can uniformly illuminate the inside of an annular light guide, and a display device including the illumination device. Is one of the purposes.

  An illumination device according to an aspect of the present invention includes a light source and a continuous annular light guide, and the light source includes a light incident structure in which light from the light source is provided in the light guide. The light guide is guided in such a way that a part of the light incident from the light incident structure is totally reflected on the surface of the light guide, and the other part of the light is guided. The light has a shape that is extracted from the annular inner peripheral surface of the light guide to the outside of the light guide.

  According to this invention, it becomes an illuminating device which irradiates annular illumination light. By applying the illumination device of the present invention to a display element that does not have a light emitting function, the entire display region can be illuminated uniformly. Further, by providing the light incident structure on the light guide, the unevenness of the illumination light due to the structure is reduced.

  In the illumination device according to one aspect of the present invention, the light guide is formed such that the center of curvature of the inner peripheral surface coincides with the center of curvature of the annular outer peripheral surface. It is good also as a structure.

  According to the present invention, non-uniform illumination light due to the structure is reduced over substantially the entire circumference of the light guide.

  In the illumination device according to one aspect of the present invention, the light incident structure is a diffraction grating provided on a part of the outer peripheral surface of the light guide, and the light source includes the light guide of the diffraction grating. May be arranged on the opposite side.

  According to the present invention, when the light from the light source is incident on the diffraction grating, the light can be propagated through the light guide plate by total reflection by the diffraction grating.

  In the illumination device according to one aspect of the present invention, the diffraction grating has a diffraction efficiency of + 1st order diffraction and a diffraction efficiency of -1st order diffraction, and the center of curvature of the annular shape of the light guide is different. It is good also as a structure formed so that diffraction anisotropy may become symmetrical with respect to the straight line which passes.

  According to the present invention, when light from the light source is incident on the diffraction grating, the diffraction grating greatly diffracts at an angle equal to or greater than the critical angle of the light guide, and becomes light that can propagate through the light guide plate with total reflection.

  In the illumination device according to one aspect of the present invention, the light incident structure is a notch provided along a circumference of the light guide, and the light source is provided on each of the plurality of surfaces of the notch. On the other hand, it is good also as a structure which has a pair of light emission part arrange | positioned so that a mutual light emission direction may oppose.

  According to the present invention, by arranging a pair of light sources in the notch so that the light emission directions are opposite to each other, light can be propagated clockwise and counterclockwise, and the light amount distribution in the light guide Can be prevented from becoming asymmetrical.

  In the illumination device according to one aspect of the present invention, the light guide may have a diffraction grating on the inner peripheral surface.

  According to the present invention, the light that has reached the inner peripheral surface of the light guide by the diffraction grating provided on the inner peripheral surface of the light guide is extracted from the light guide plate by diffraction and surrounded by the inner peripheral surface ( Illumination area) can be illuminated.

  The illuminating device in one aspect of this invention WHEREIN: The internal peripheral surface of the said light guide is good also as a structure which is a surface which diffuses light.

  According to the present invention, a structure for diffusing light is formed on the inner peripheral surface of the light guide, and when light propagating through the light guide plate hits the inner peripheral surface, the light is diffused and extracted from the light guide plate. A region (illumination region) surrounded by the inner peripheral side surface is illuminated.

  The illuminating device in one aspect of the present invention may further include a reflecting member disposed around the light guide at a distance from the outer peripheral surface.

  According to the present invention, the light emitted from the outer peripheral surface of the light guide can be reflected in the light guide and used for illumination. Thereby, light that does not contribute to illumination and is wasted can be eliminated, and the light use efficiency can be improved.

  The lighting device according to one aspect of the present invention may be configured such that a transparent base is provided on a side of the light guide that intersects the inner peripheral surface and the outer peripheral surface.

  ADVANTAGE OF THE INVENTION According to this invention, the dustproof property and waterproofness of an illuminating device can be improved.

  The illumination device according to one aspect of the present invention may further include a first spacer disposed between the light guide and the transparent substrate, and the light guide may be separated from the transparent substrate. Good.

  According to the present invention, it is possible to suppress light leakage from the light guide by providing a space between the light guide and the transparent substrate.

  A display device according to an aspect of the present invention includes the above-described lighting device and an object to be illuminated illuminated by light from the lighting device, and the lighting device is on an observer side of the object to be illuminated. It is characterized by being arranged in.

  According to the present invention, when the display element itself is applied to a reflective display element that does not have a light emitting function, the display element can be uniformly illuminated by the illumination device that functions as auxiliary illumination of the display element.

  The display device according to one aspect of the present invention may further include a second spacer disposed between the illumination device and the object to be illuminated, and the illumination device may be separated from the object to be illuminated. Good.

  ADVANTAGE OF THE INVENTION According to this invention, the light leakage from an illuminating device can be suppressed by providing space between a to-be-illuminated body and an illuminating device.

  In the display device according to one aspect of the present invention, the object to be illuminated includes an element substrate, a counter substrate facing the element substrate, and a display layer sandwiched between the element substrate and the counter substrate. It is good also as a structure which is a reflective display element which reflects and reflects the light from the said illuminating device.

  According to the present invention, when the display element itself is applied to a reflective display element that does not have a light emitting function, the display element can be uniformly illuminated by the illumination device that functions as auxiliary illumination of the display element.

(A) is the top view which looked at the reflective liquid crystal device to which this invention was applied from the counter substrate side with each component, (B) is AA 'sectional drawing of (A). (A) is a plan view of pixels adjacent to each other in an element substrate used in a reflective liquid crystal device to which the present invention is applied, and (B) is an element substrate at a position corresponding to the line BB ′ in (A). Sectional drawing when cut. (A) is a top view which shows schematic structure of the illuminating device in 1st Embodiment, (B) is sectional drawing which follows the C-C 'line of (A). (A) is a top view which shows the whole structure of the display apparatus of 2nd Embodiment, (B) is sectional drawing which shows the whole structure of the display apparatus of 2nd Embodiment. (A) is a top view which shows the whole structure of the display apparatus of 3rd Embodiment, (B) is sectional drawing which shows the whole structure of the display apparatus of 3rd Embodiment. (A) is a top view which shows the whole structure of the display apparatus of 4th Embodiment, (B) is sectional drawing which shows the whole structure of the display apparatus of 4th Embodiment. Sectional drawing which shows the whole structure of the display apparatus of 5th Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

[First Embodiment]
FIG. 1A is a plan view of a reflective liquid crystal device 100 to which the present invention is applied as viewed from the side of a counter substrate together with each component, and FIG. 1B is a cross-sectional view taken along line AA ′ of FIG. is there.
The display device 1 (FIG. 3) of the present embodiment includes a reflective liquid crystal device (display element) 100 and an illumination device 40 (FIG. 3).

"Structure of reflective LCD panel"
First, the configuration of the reflective liquid crystal panel of the first embodiment will be described.
As shown in FIGS. 1A and 1B, in the reflective liquid crystal device (display element; illuminated body) 100, the element substrate 10 and the counter substrate 20 are interposed via a predetermined gap. The sealing material 107 is bonded together, and the sealing material 107 is disposed along the edge of the counter substrate 20.

  The sealing material 107 is an adhesive made of a photo-curing resin or a thermosetting resin, and a gap material such as glass fiber or glass beads for setting the distance between the element substrate 10 and the counter substrate 20 to a predetermined value. Is blended.

  In the present embodiment, the support substrate of the element substrate 10 is a translucent substrate 10d, and the support substrate of the counter substrate 20 is a translucent substrate 20d.

  In the element substrate 10, the data line driving circuit 101 and the plurality of terminals 102 are formed along the periphery of the element substrate 10 in the outer region of the sealing material 107, and both sides of the data line driving circuit 101 and the plurality of terminals 102 are formed. Each of the scanning line driving circuits 104 is formed. In at least one location of the counter substrate 20, a vertical conductive material 109 is formed for electrical conduction between the element substrate 10 and the counter substrate 20.

As will be described in detail later, on the element substrate 10, light-reflective pixel electrodes 9a are formed in a matrix.
On the other hand, a frame 108 made of a light-shielding material is formed in the inner area of the sealing material 107 on the counter substrate 20, and the inner side is an image display area 10 a. A common electrode 21 made of an ITO (Indium Tin Oxide) film is formed on the counter substrate 20. Note that a light shielding film (not shown) called a black matrix or a black stripe may be formed on the counter substrate 20 at a position facing the space between the pixel electrodes 9a.

  In addition, in the pixel area 10b, a dummy pixel may be configured in an area overlapping with the frame 108. In this case, an area excluding the dummy pixel in the pixel area 10b is used as the image display area 10a. become.

  Note that the frame 108 of the counter substrate may be eliminated, and a frame made of a light shielding material may be formed on the element substrate side.

  In the reflective liquid crystal device 100 formed in this way, light incident from the counter substrate 20 side is reflected by the pixel electrode 9 a and is again emitted from the counter substrate 20 side by the liquid crystal layer (display layer) 50. As a result of light modulation for each pixel, an image is displayed. Here, the reflective liquid crystal device 100 can be used as a color display device of an electronic device such as a mobile computer or a mobile phone. In this case, a color filter (not shown) or a protective film is formed on the counter substrate 20. Is done.

  Further, on the surface on the light incident side of the counter substrate 20 and the element substrate 10, the type of the liquid crystal layer 50 to be used, that is, an operation mode such as TN (twisted nematic) mode, STN (super TN) mode, or normally white Depending on the mode / normally black mode, a polarizing film, a retardation film, a polarizing plate, and the like are arranged in a predetermined direction.

  Further, a dichroic filter that produces RGB colors using the interference action of light may be formed by stacking multiple layers of interference layers having different refractive indexes on the counter substrate 20. According to the counter substrate with the dichroic filter, brighter color display can be performed.

(Configuration of each pixel)
2A is a plan view of adjacent pixels in the element substrate 10 used in the reflective liquid crystal device 100 to which the present invention is applied, and FIG. 2B corresponds to the line BB ′ in FIG. It is sectional drawing when the element substrate 10 is cut | disconnected in the position which carries out. 2A, the pixel electrode 9a is indicated by a long dotted line, the data line 6a is indicated by a one-dot chain line, the scanning line 3a and the capacitor line 3b are indicated by solid lines, and the semiconductor layer 1a is indicated by a short and thin dotted line. It is shown.

  As shown in FIGS. 2A and 2B, the element substrate 10 includes a first surface 10x and a second surface 10y of a translucent substrate 10d (support substrate) made of a quartz substrate, a glass substrate, or the like. A light-transmitting base insulating layer 15 made of a silicon oxide film or the like is formed on the first surface 10x positioned on the counter substrate 20 side, and an N-channel type thin film transistor is positioned on the upper layer side so as to overlap with the pixel electrode 9a. 30 is formed.

  In the thin film transistor 30, a channel region 1g, a low concentration source region 1b, a high concentration source region 1d, a low concentration drain region 1c, and a high concentration drain region 1e are formed on the semiconductor layer 1a made of an island-shaped polysilicon film. LDD structure.

  A translucent gate insulating layer 2 made of a silicon oxide film or a silicon nitride film is formed on the surface side of the semiconductor layer 1a, and a gate made of a metal film or a doped silicon film is formed on the surface of the gate insulating layer 2. Electrodes (scanning lines 3a) are formed.

  Although the thin film transistor 30 has an LDD (Lightly Doped Drain) structure, a structure in which a high concentration source region and a high concentration drain region are formed in a self-aligned manner on the scanning line 3a may be adopted.

  In addition, the capacitor line 3b is opposed to the portion extending from the high concentration drain region 1e in the semiconductor layer 1a with the gate insulating layer 2 interposed therebetween, and a storage capacitor 60 is formed.

  On the upper layer side of the thin film transistor 30, interlayer insulating layers 7 and 8 are formed. A data line 6 a made of a metal film or a doped silicon film is formed on the surface of the interlayer insulating layer 7. The data line 6 a is electrically connected to the high concentration source region 1 d through a contact hole 7 a formed in the interlayer insulating layer 7. Connected.

  A light-reflective pixel electrode 9a made of a single aluminum film, an aluminum alloy film, a single silver film, a silver alloy film, or a laminated film thereof is formed on the surface of the interlayer insulating layer 8, and an alignment film 16 is formed thereon. Is formed. The pixel electrode 9a is electrically connected to the high-concentration drain region 1e through a contact hole 8a formed in the interlayer insulating layers 7 and 8.

  The pixel electrode 9a is formed of a light-transmitting thin film such as an ITO film, and a light reflecting layer composed of an aluminum simple film, an aluminum alloy film, a silver simple film, a silver alloy film, or a laminated film thereof is formed on the lower layer side. Sometimes it forms.

  As shown in FIG. 1B, the element substrate 10 configured in this manner is disposed to face the counter substrate 20 so that the pixel electrode 9a and the common electrode 21 face each other, and between these substrates, A liquid crystal layer 50 as an electro-optical material is sealed in a space surrounded by the sealing material 107.

  The liquid crystal layer 50 is not shown in the alignment film 26 (not shown in FIG. 1B) formed on the element substrate 10 and the counter substrate 20 shown in FIG. 2B in a state where an electric field from the pixel electrode 9a is not applied. ) To take a predetermined orientation state. The liquid crystal layer 50 is made of, for example, one or a mixture of several types of nematic liquid crystals.

"Lighting device 40"
Next, the structure of the illuminating device 40 of 1st Embodiment is described.
FIG. 3A is a plan view showing a schematic configuration of the illumination device 40 in the first embodiment, and FIG. 3B is a cross-sectional view taken along the line CC ′ in FIG.

  The illumination device 40 is disposed on the counter substrate 20 of the reflective liquid crystal device (display element; illuminated body) 100 and functions as a device that illuminates the reflective liquid crystal device 100.

  As shown in FIG. 3A, the overall configuration of the lighting device 40 is formed in a circular shape in plan view. The illumination device 40 includes a light guide 42, a first diffraction grating 11, a second diffraction grating 22, a mirror (reflection member) 14, and a light emitting diode (light source) 13. The light incident structure in the present invention includes a first diffraction grating 11 and a light emitting diode 13.

  The light guide 42 is formed in a continuous circular annular shape as viewed from the normal direction of the upper surface 42a, and a central hole 42A for exposing the display region 10a of the reflective liquid crystal device 100 is provided at the center. . The light guide 42 includes an upper surface 42a, a lower surface 42b opposite to the upper surface 42a, an inner peripheral surface 42c that connects one end sides of the upper surface 42a and the lower surface 42b and constitutes a wall surface of the center hole 42A, and an upper surface 42a and a lower surface. And an outer peripheral surface 42d connecting the other end sides of 42b. As shown in FIG. 3A, the radii of curvature of the outer peripheral surface 42d and the inner peripheral surface 42c of the light guide 42 are R1 and R2, respectively, and the center of curvature of the inner peripheral surface 42c and the center of curvature C of the outer peripheral surface 42d. Are consistent with each other.

  Examples of the material of the light guide 42 include glass and a transparent resin material. In this embodiment, a light guide 42 made of a transparent resin material is used to reduce the weight of the entire apparatus. The dimensional shape of the light guide 42 is, for example, about 0.5 mm in thickness and about 3 mm in width, and has a predetermined diameter. The light guide 42 is formed in an annular shape that allows the display region 10a of the reflective liquid crystal device 100 to be exposed from the center hole 42A.

  The first diffraction grating 11 is provided on a part of the outer peripheral surface 42 d of the light guide 42. The first diffraction grating 11 is a diffraction grating that deflects the light from the light emitting diode 13 by diffraction, and increases the diffraction efficiency of the order that is diffracted in a specific direction. Specifically, the diffraction efficiency of the + 1st order diffraction is different from the diffraction efficiency of the −1st order diffraction, and the diffraction anisotropy is symmetric with respect to the center line M passing through the center of curvature of the light guide 42. It has characteristics. The first diffraction grating 11 of the present embodiment constitutes a blaze structure 11A having a sawtooth cross section.

  The blaze structure 11A is configured by arranging a plurality of minute structures having a triangular cross section in parallel. The minute structure constituting the blaze structure 11 </ b> A has a plurality of first surfaces 12 and a plurality of second surfaces 17. As shown in FIG. 3A, the blaze structure 11 </ b> A is a sawtooth formed by a plurality of first surfaces 12 and a plurality of second surfaces 17 with respect to a center line M passing through the center of curvature of the light guide 42. It is comprised so that a shape may become symmetrical.

  The second diffraction grating 22 is formed on the inner peripheral surface 42c of the light guide 42, and is made of a surface relief type diffraction grating having a fine concavo-convex structure.

  The second diffraction grating 22 has a grating pattern configured by arranging a plurality of linear gratings extending in the Z direction in the circumferential direction along the inner circumferential surface 42 c of the light guide 42. ing. The lattice period (arrangement pitch) of the lattice pattern is P. The depth and pitch P of the grating pattern are appropriately determined according to the required diffraction efficiency.

  The light emitting diode 13 is an LED that emits white light. The light emitting diode 13 is disposed on the opposite side of the light guide 42 with its light exit surface facing the first diffraction grating 11, and emits light toward the first diffraction grating 11.

  The light source is not limited to the light emitting diode 13 but may be a solid light emitting element such as a laser diode (LD) in addition to the LED. Further, as the light source, a single or a combination of a plurality of such solid light emitting elements can be used.

  The mirror 14 is formed in an annular shape, and is disposed outside the light guide 42 so as to surround the periphery of the light guide 42. The mirror 14 is disposed at a distance from the outer peripheral surface 42 d of the light guide 42 and is not in contact with the light guide 42. The mirror 14 is provided with an opening 14a in a part in the circumferential direction. The opening 14 a has a size that does not block light from the light emitting diode 13, and light from the light emitting diode 13 can enter the light guide 42 through the opening 14 a. The fixing method of the mirror 14 is set as appropriate, and is fixed to, for example, a housing (not shown) that holds the illumination device 40 and the reflective liquid crystal device 100.

  The lighting device 40 described above is fixed on the counter substrate 20 of the reflective liquid crystal device 100. In this way, the display device 1 of the present embodiment is configured.

  In the illuminating device 40 of the present embodiment, the white light W emitted from the light emitting diode 13 is split into red light R, green light G, and blue light B by the blaze structure 11A of the first diffraction grating 11. In addition, each color light is diffracted at different angles and emitted into the light guide 42. Since the diffraction angle by the first diffraction grating 11 varies depending on the wavelength, the red component, the green component, and the blue component of the light emitted from the light emitting diode 13 are separated from each other. Each color light emitted into the light guide 42 is greatly diffracted left and right at an angle equal to or greater than the critical angle of the light guide 42 and propagates through the light guide 42 in total clockwise and counterclockwise directions. To do. Specifically, the light propagates in the circumferential direction of the light guide 42 while repeating total reflection between the inner peripheral surface 42 c and the outer peripheral surface 42 d of the light guide 42. Since the periphery of the light guide 42 is an air layer, the light incident on the light guide 42 is an interface with the air layer, that is, the outer peripheral surface 42d of the light guide 42 or the interface between the inner peripheral surface 42c and the air layer. Is totally reflected.

  Here, in order to introduce the light from the light emitting diode 13 into the light guide 42 at an angle larger than the critical angle, the grating period of the first diffraction grating 11 needs to be set to submicron.

  As described above, the blaze structure 11 </ b> A of the first diffraction grating 11 is configured so that the sawtooth shape is symmetric with respect to the center line M. Therefore, the light from the light emitting diode 13 is diffracted in the left and right directions in the first diffraction grating 11 and propagates in the opposite directions in the light guide 42. Thereby, it is possible to suppress the light amount distribution in the light guide 42 from becoming asymmetrical on the left and right of the center line M.

  Of the light propagating in the light guide 42, each color light transmitted through the inner peripheral surface 42c and incident on the second diffraction grating 22 is extracted from the light guide 42 by diffraction by the second diffraction grating 22, A region surrounded by the inner peripheral surface 42c of the light guide 42 is emitted into the center hole 42A. In other words, the light emitted into the light guide 42 is gradually emitted into the center hole 42A through the second diffraction gratings 22 while propagating in the light guide 42 in the circumferential direction. The inside of 42A is irradiated uniformly. Thereby, it becomes the illuminating device 40 which shines circularly. In the present embodiment, each color light is emitted from the light guide 42 into the center hole 42 </ b> A via the second diffraction grating 22. For this reason, the light emitted from the illumination device 40 is white light W.

  In the present embodiment, only the light emitted from the outer peripheral surface 42d of the light guide 42 is reflected by the mirror 14 and returned into the light guide 42. The mirror 14 is disposed at a distance from the outer peripheral surface 42 d of the light guide 42. By providing a space between the light guide 42 and the mirror 14, light absorption by the mirror 14 can be suppressed.

  The white light emitted from the illumination device 40 becomes illumination light that illuminates the display area 10a of the reflective liquid crystal device 100 exposed from the opening of the illumination device 40 (the central hole 42A of the light guide 42). According to the illumination device 40 of the present embodiment, the entire display area 10a can be illuminated uniformly.

  A circular opening (a central hole 42A of the light guide 42) existing inside the illumination device 40 has substantially the same opening area as the display region 10a, and the display region 10a of the reflective liquid crystal device 100 extends from the central hole 42A. Is exposed. For example, when the display device is a wristwatch, the outer shape is often circular. Therefore, by providing the annular illumination device 40 on the observer side of the reflective liquid crystal device 100, the display area 10a of the reflective liquid crystal device 100 can be illuminated uniformly.

  Further, since the illumination device 40 includes the light guide 42 having an annular shape, the display region 10a of the reflective liquid crystal device 100 is not covered by the light guide 42, and the display region can be displayed even when it is not irradiated. The image displayed on 10a can be clearly seen.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
The basic configuration of the display device of the present embodiment described below is substantially the same as that of the first embodiment, but is different in the light incident structure of the irradiation device. Therefore, in the following description, a different point from 1st Embodiment is demonstrated in detail, and description of a common location is abbreviate | omitted. Moreover, in each drawing used for description, the same code | symbol shall be attached | subjected to the same component as FIGS. 1-3.

FIG. 4A is a plan view showing the overall configuration of the display device of the second embodiment. FIG. 4B is a cross-sectional view illustrating the overall configuration of the display device according to the second embodiment.
As shown in FIGS. 4A and 4B, the display device 4 in the present embodiment includes an illumination device 52 having a light guide 42, a pair of light emitting diodes 13 </ b> A and 13 </ b> B, and a mirror 14. Yes. The light incident structure in the present invention includes a notch 43 provided in a part of the light guide 42 in the circumferential direction, and a pair of light emitting diodes 13A and 13B disposed in the notch 43. The pair of light emitting diodes (light emitting portions) 13 </ b> A and 13 </ b> B has a notch portion 43 such that the light emission directions of the pair of light guide incident light surfaces 43 a and 43 b constituting the side surface of the notch portion 43 are opposite to each other. Is placed inside.

  The light guide 42 has a notch 43 formed in a part in the circumferential direction. The notch 43 has a concave shape in plan view formed so as to be recessed from the outer peripheral surface 42d of the light guide 42 toward the inner peripheral surface 42c. A pair of light guiding / incident surfaces 43a and 43b constituting the side surface of the cutout portion 43 is perpendicular to the outer peripheral surface 42d. Therefore, the light incident on the inside of the light guide 42 from these light guide incident light surfaces 43a and 43b propagates in the circumferential direction while totally reflecting the inside of the annular light guide 42.

  The shape of the notch 43 is not limited to the above. However, it is preferable that the light guide incident surfaces 43a and 43b are perpendicular to the outer peripheral surface 42d.

  In addition, the first light emitting diode 13A is disposed with its light exit surface facing the first light guide light incident surface 43a, and the second light emitting diode 13B is disposed with its light exit surface opposed to the second light guide light incident surface 43b. Accordingly, the lights L1 and L2 emitted from the light emitting diodes 13A and 13B propagate in the light guide 42 in the opposite directions. The light L1 emitted from the first light emitting diode 13A propagates clockwise, and the light L2 emitted from the second light emitting diode 13B propagates counterclockwise. Thereby, it can suppress that the light quantity distribution in the light guide 42 becomes left-right asymmetric.

A light diffusion structure for diffusing light emitted from the inner peripheral surface 42 c of the light guide 42 to the center hole 42 </ b> A is formed on the inner peripheral surface 42 c of the light guide 42. Specifically, it is configured by a light diffusing element 44 constituted by a large number of elliptical cylinders also made of a light transmissive material on the inner peripheral surface 42c of the light guide 42 made of a light transmissive material such as glass or resin. Yes. The light diffusing element 44 may employ other structures such as a trapezoidal columnar shape, a triangular columnar shape, and a semi-cylindrical shape in addition to the elliptical columnar shape.
Further, the light diffusion structure may be formed by performing uneven processing on the inner peripheral surface 42 c of the light guide 42. Alternatively, a light diffusion sheet may be separately provided on the inner peripheral surface 42 c of the light guide 42.

  According to the illumination device 52 of the present embodiment, the lights L1 and L2 emitted from the light emitting diodes 13A and 13B are incident from the light guide incident light surfaces 43a and 43b of the light guide 42, respectively. Propagating while totally reflecting in the clockwise direction or counterclockwise direction. When the light incident on the light guide 42 repeats total reflection between the inner peripheral surface 42c and the outer peripheral surface 42d of the light guide 42, a part of the light is refracted on the inner peripheral surface 42c and the light guide 42 It is injected inside. Since the light diffusion structure is provided on the inner peripheral surface 42c of the light guide 42 of the present embodiment, the light transmitted through the inner peripheral surface 42c is diffused and emitted by the light diffusion element 44 described above. . The light diffused in the light diffusing element 44 is diffused isotropically. Therefore, the light diffused toward the outer peripheral surface 42d side of the light guide 42 in a direction other than the center hole 42A is reflected by the mirror 14 disposed outside the light guide 42 and travels toward the center hole 42A. It becomes.

  Thus, by providing the light diffusion structure on the inner peripheral surface 42c side of the light guide 42, every time the light propagating in the light guide 42 enters the inner peripheral surface 42c, a part of the light is diffused. As a result, the region surrounded by the inner peripheral surface 42c (the display region 10a of the reflective liquid crystal device 100) can be uniformly illuminated.

The light diffusivity of the light diffusing element 44 is appropriately set according to the amount of light necessary for the illumination device 52. If the light diffusibility is too strong, the portion of the annular light guide 42 close to the light emitting diodes 13A and 13B is brightest, and the portion far from the light emitting diode 13 does not reach the light and becomes dark. That is, it is considered that a large amount of light is extracted from the light diffusing element 44 in a portion close to the light emitting diode 13 and the amount of light propagating in the light guide 42 is reduced.
Therefore, it is desirable to determine the light diffusive diffusion intensity according to the amount of light extracted from the inner peripheral surface 42c of the light guide 42 through the light diffusing element 44 to the center hole 42A.

  As described above, in order to uniformly emit light from the light guide 42 over the entire circumference, in addition to the light emitted from the inner peripheral surface 42 c of the light guide 42, the entire light guide 42 is entirely inside. It is necessary to leave the light propagating while reflecting in the light guide 42. Considering this, the light diffusivity of the light diffusing element 44 is determined, and the light is uniformly emitted in the circumferential direction of the light guide 42.

  In addition, although the light diffusivity of the light-diffusion element 44 in this embodiment is uniform over the circumferential direction of the light guide 42, it is not restricted to this. For example, by making the light diffusivity near the light emitting diode 13 weaker than the light diffusivity far from the light emitting diode 13, a lot of light is emitted from a portion near the light emitting diode 13 and becomes too bright. Can be prevented. That is, in order to suppress the difference in brightness of the illumination light in the circumferential direction of the light guide 42, it is effective to increase the light diffusibility of the light diffusing element 44 as the distance from the light emitting diode 13 increases.

  Moreover, although the light-diffusion element 44 was formed over the circumferential direction of the light guide 42, it is not restricted to this. For example, it may be partially divided. However, in order to obtain high uniformity of illumination light, it is effective to form the light diffusing element 44 in the entire circumferential direction of the light guide 42.

  If priority is given to the size and cost of the illumination device 52 over the amount of illumination light, the mirror 14 provided around the light guide 42 can be omitted.

[Third Embodiment]
Next, a third embodiment of the present invention will be described.
The basic configuration of the display device of the present embodiment described below is substantially the same as that of the first embodiment, but is different in the light incident structure of the irradiation device. Therefore, in the following description, a different point from 1st Embodiment is demonstrated in detail, and description of a common location is abbreviate | omitted. Moreover, in each drawing used for description, the same code | symbol shall be attached | subjected to the same component as FIGS. 1-3.

FIG. 5A is a plan view showing the overall configuration of the display device of the third embodiment. FIG. 5B is a cross-sectional view showing the overall configuration of the display device of the third embodiment.
As shown in FIGS. 5A and 5B, the display device 5 in the present embodiment includes an illumination device 53 having a light guide 42, a blazed diffraction grating 45, a light emitting diode 13, and a mirror 14. It is prepared for. The light incident structure in the present invention includes a blazed diffraction grating 45 provided in a part of the light guide 42 in the circumferential direction, and the light emitting diode 13 that emits light toward the blazed diffraction grating 45.

  In the light guide 42 of the present embodiment, a fine sawtooth blazed diffraction grating 45 is provided on a part of the outer peripheral surface 42d. The blazed diffraction grating 45 can increase the diffraction efficiency of the orders diffracted in a specific direction, and has the same configuration as the first diffraction grating described in the previous embodiment. As shown in FIG. 5A, the blazed diffraction grating 45 is configured such that the sawtooth shape is symmetric with respect to the center line M passing through the annular curvature center C of the light guide 42. A light diffusing structure including a light diffusing element 44 is provided on the inner peripheral surface 42 c of the light guide 42.

In the illuminating device 53 of this embodiment, when the light from the light emitting diode 13 enters the blazed diffraction grating 45, the light is split into both sides of the center line M by the blazed diffraction grating 45, and the lights L1 and L2 are guided to the light guide 42. The light is greatly diffracted at an angle equal to or greater than the critical angle, and propagates in the light guide 42 while being totally reflected in opposite directions.
Each time the lights L1 and L2 propagating in the light guide 42 enter the inner peripheral surface 42c, a part of the light is diffused in the light diffusing element 44 and extracted to the central hole 42A.

  In this way, light is gradually extracted into the center hole 42A over the circumferential direction of the light guide 42. Thereby, the display area 10a of the reflective liquid crystal device 100 in the center hole 42A can be illuminated uniformly.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described.
The basic configuration of the display device of the present embodiment described below is substantially the same as that of the first embodiment, but differs in that a spacer is provided between the irradiation device and the reflective liquid crystal device. Therefore, in the following description, a different point from 1st Embodiment is demonstrated in detail, and description of a common location is abbreviate | omitted. Moreover, in each drawing used for description, the same code | symbol shall be attached | subjected to the same component as FIGS. 1-3.

FIG. 6A is a plan view showing the overall configuration of the display device of the fourth embodiment. FIG. 6B is a cross-sectional view illustrating the overall configuration of the display device according to the fourth embodiment.
In the display device 27 of the present embodiment, as shown in FIGS. 6A and 6B, the illumination device 54 and the reflective liquid crystal device 100 include a plurality of spacers (first spacers) 18 and a plurality of spacers (first spacers). The spacers 19 are attached to each other. The plurality of spacers 18 and the plurality of spacers 19 have prismatic shapes having the same dimensions, and are respectively disposed between the light guide 42 of the illumination device 54 and the counter substrate 20 of the reflective liquid crystal device 100. The plurality of spacers 18 are arranged at predetermined intervals along the inner peripheral surface 42 c of the light guide 42, and the plurality of spacers 19 are arranged at predetermined intervals along the outer peripheral surface 42 d of the light guide 42. Has been placed.

  The light incident on the light guide 42 emitted from the light emitting diode 13 propagates while repeating total reflection in the light guide 42. When the entire lower surface 42b of the light guide 42 is in contact with the counter substrate 20 of the reflective liquid crystal device 100, light leakage may occur from the lower surface 42b to the counter substrate 20 side. Therefore, by providing the space 57 between the light guide 42 and the reflective liquid crystal device 100 by the spacers 18 and 19, the entire periphery of the light guide 42 is substantially surrounded by the air layer. Total reflection occurs at the interface, and light leakage from the light guide 42 can be significantly suppressed.

  Thereby, the light inject | emitted from the inner peripheral surface 42c side of the light guide 42 to 42 A of center holes increases, and it can obtain more bright and uniform illumination light.

The number and shape of the spacers 18 and 19 can be variously changed.
Further, instead of the spacers 18 and 19, a reflective layer may be provided between the light guide 42 and the counter substrate 20 of the reflective liquid crystal device 100. Since the metal film easily absorbs light, it is preferable to use a reflective layer made of a dielectric multilayer film. Although it is desirable that the light is totally reflected in the light guide 42, the present invention is not limited to this, and a member that can return the light into the light guide 42 by reflection so as to suppress the leakage of the light from the light guide 42. If it is.

  The configuration using the spacers 18 and 19 of the present embodiment can be applied to the illumination devices of other embodiments.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described.
FIG. 7 is a cross-sectional view showing the overall configuration of the display device of the fifth embodiment.
The basic configuration of the display device of the present embodiment described below is substantially the same as that of the fourth embodiment, but differs in that a cover glass (transparent substrate) is provided on the surface. Therefore, in the following description, a different point from 1st Embodiment is demonstrated in detail, and description of a common location is abbreviate | omitted. Moreover, in each drawing used for description, the same reference numerals are given to components common to the previous embodiment.

  As in the fourth embodiment, the display device 55 in the present embodiment is configured by bonding the lighting device 54 and the reflective liquid crystal device 100 via spacers (second spacers) 28 and 29. The difference from the previous embodiment is that a cover glass (transparent substrate) 23 is provided on the outermost layer of the display device 55. The cover glass 23 is provided on the upper surface 42 a side that intersects the inner peripheral surface 42 c and the outer peripheral surface 42 d of the light guide 42.

  The cover glass 23 is bonded to the surface of the lighting device 54 via the spacers 28 and 29. The spacers 28 and 29 are the same as the spacers 18 and 19 disposed between the illumination device 54 and the reflective liquid crystal device 100, and have a predetermined interval in the circumferential direction on the upper surface 42 a of the light guide 42. Are arranged. The cover glass 23 plays a role of protecting the display device 55, and can improve the dust resistance and waterproofness of the display device 55. Further, the rigidity as the display device 55 is also improved.

  In the present embodiment, the cover glass 23 is arranged on the lighting device 54 via the spacers 28 and 29. For this reason, a space 57 is formed between the light guide 42 and the cover glass 23, and an air layer exists, so that light leakage from the light guide 42 can be suppressed. Further, a part of the light emitted from the inner peripheral surface 42 c of the light guide 42 toward the cover glass 23 can be reflected by the cover glass 23 and returned to the light guide 42 again.

Note that an antireflection film may be provided on the surface 23 a on the viewer side of the cover glass 23. Further, the back surface 23b of the cover glass 23 has a high reflectance with respect to light having a large incident angle with respect to the normal direction of the back surface 23b, and is substantially smaller than light having a small incident angle, that is, the back surface 23b. A functional film that increases the transmittance for light incident at a perpendicular angle may be formed.
The antireflection film and the functional film described above may be provided on the entire surface 23a or the back surface 23b of the cover glass 23, or may be provided partially.

  According to the configuration of the present embodiment, the observer can visually recognize the display image on the display element by utilizing the reflection of light on the cover glass 23. Further, by providing a structure for reflecting a part of the light emitted from the inner peripheral surface 42c of the light guide 42 on the viewer side of the light guide 42, the light component toward the center of the display region 10a is increased and the display is performed. The uniformity of the illumination light distribution in the region 10a can be improved.

  As mentioned above, although each embodiment was described including a modification, the illuminating device in this invention is equipped with the cyclic | annular light guide 42 and the light emitting diode 13, and irradiates cyclic | annular illumination light from the circumference | surroundings of the display area in a display element. It has a function to do. Therefore, various configurations can be changed as the lighting device based on this concept.

  In the previous embodiment, the reflective liquid crystal device 100 has been exemplified as the display element according to the present invention. However, the present invention is not limited to this, and various reflective types that do not have a light emitting function such as an electrophoretic display and an electrochromic display. The display element can be used. Non-light-emitting displays consume less power and are used as display devices for wristwatches and portable electronic devices. Therefore, the embodiment of the display device is not limited to a wristwatch, and can be applied to a vehicle-mounted meter, a portable electronic device, and the like. Further, the illuminated object is not limited to a non-light emitting display.

  By using the lighting device according to the present invention for a non-light-emitting display or a device that does not have a lighting function, the display area and other predetermined areas can be illuminated uniformly, and illumination light such as at night or in a dark room can be emitted. The display is easy to see even in environments where there is not.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to. You may combine the structure of each embodiment suitably.

  In each of the previous embodiments, an annular illumination device has been described. However, the illumination device is not limited to a circular shape, and may be another annular shape. In other words, any other shape may be used as long as it has a closed curve shape or a polygonal shape without end portions.

  DESCRIPTION OF SYMBOLS 1,55 ... Display apparatus, 10 ... Element board | substrate, 11 ... 1st diffraction grating, 22 ... 2nd diffraction grating, 13 ... Light emitting diode (light source), 13A, 13B ... Light emitting diode (light emission part), 14 ... Mirror (reflection) Members), 18, 19 ... spacer (first spacer), 28, 29 ... spacer (second spacer), 20 ... counter substrate, 40, 52, 53, 54 ... lighting device, 42 ... light guide, 42a ... top surface 42b ... lower surface, 42c ... inner peripheral surface, 42d ... outer peripheral surface, 43 ... notch, 50 ... liquid crystal layer (display layer), L1, L2 ... light, 100 ... reflective liquid crystal device (display element; illuminated body) )

Claims (13)

A light source;
A continuous annular light guide, and
The light source is arranged so that light from the light source enters the light incident structure provided in the light guide,
In the light guide, a part of the light incident from the light incident structure is totally reflected on the surface of the light guide to guide the light, and the other part of the light is the light of the light guide. An illuminating device having a shape that is taken out from an annular inner peripheral surface to the outside of the light guide. The light guide is
The lighting device according to claim 1, wherein the center of curvature of the inner peripheral surface and the center of curvature of the annular outer peripheral surface coincide with each other. The light incident structure is a diffraction grating provided on a part of the outer peripheral surface of the light guide,
The lighting device according to claim 1, wherein the light source is disposed on a side of the diffraction grating opposite to the light guide.   The diffraction grating has a diffraction efficiency of + 1st order diffraction and a diffraction efficiency of -1st order diffraction, and the diffraction anisotropy is symmetric with respect to a straight line passing through the center of curvature of the annular shape of the light guide. It is formed so that it may become. The illuminating device of Claim 3 characterized by the above-mentioned. The light incident structure is a notch provided along the circumference of the light guide,
3. The illumination according to claim 1, wherein the light source includes a pair of light emitting units arranged so that light emission directions of the plurality of surfaces of the cutouts are opposite to each other. apparatus.   The lighting device according to claim 1, wherein the light guide has a diffraction grating on the inner peripheral surface.   The lighting device according to claim 1, wherein an inner peripheral surface of the light guide is a surface that diffuses light.   The illumination device according to any one of claims 1 to 7, further comprising a reflection member disposed around the light guide body at a distance from the outer peripheral surface.   The lighting device according to any one of claims 1 to 8, wherein a transparent base is provided on a side of the light guide body that intersects the inner peripheral surface and the outer peripheral surface. A first spacer disposed between the light guide and the transparent substrate;
The lighting device according to claim 9, wherein the light guide is separated from the transparent substrate. The lighting device according to any one of claims 1 to 9,
An illuminated body illuminated by light from the illumination device,
The display device, wherein the illumination device is arranged on an observer side of the illuminated body. A second spacer disposed between the illumination device and the object to be illuminated;
The display device according to claim 11, wherein the illumination device is separated from the object to be illuminated.   The object to be illuminated reflects light from the illumination device including an element substrate, a counter substrate facing the element substrate, and a display layer sandwiched between the element substrate and the counter substrate. The display device according to claim 11, wherein the display device is a reflective display element that performs display.

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