JP2010257672A - Lighting device, image display device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect quantity of light incident to an illuminated object in a lighting device without enlarging a size of the device. <P>SOLUTION: The lighting device has a transparent sealing substrate 214, a transparent lighting substrate 210 opposite to the sealing substrate 214, light-emitting elements 211 arranged between the sealing substrate 214 and the lighting substrate 210 and to light-emit toward the lighting substrate 210, light detection elements arranged between the sealing substrate 214 and the lighting substrate 210 and outputting detection signals of sizes corresponding to the quantity of light incident from the lighting substrate 210, and light shielding layers 213 formed on the sealing substrate 214 and shielding light incident from the sealing substrate 214 to the light detection element. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lighting device, an image display device, and an electronic apparatus.

  Patent Documents 1 and 2 describe an image display device including a reflective liquid crystal display device that reflects external light and displays an image, and a front light that illuminates the device from the front surface (display surface). . This image display device has an advantage that the display quality does not deteriorate even when a sufficient amount of external light is not incident on the liquid crystal display device. The front light of this image display device includes an organic EL (Electro Luminescent) element as a light source. The organic EL elements are arranged, for example, in a lattice shape so as to illuminate the display surface of the liquid crystal display device without omission.

Japanese Patent No. 3797007 (FIG. 5) JP 2006-154402 A (FIG. 1)

  Although not described in Patent Documents 1 and 2, in a reflective display device with a front light, it is desirable to adjust the brightness (light emission amount) of the front light based on the amount of light incident on the display surface. For example, from the viewpoint of power saving, it is desirable to turn off the front light if the amount of external light incident on the display surface is sufficiently large. For example, if the amount of light incident on the display surface decreases, the amount of light emitted by the front light increases, and if the amount of light incident on the display surface increases, the amount of light emitted by the front light decreases, the power consumption without degrading the display quality. Can be reduced.

  As a method for enabling the above adjustment, an optical sensor for detecting the amount of external light directed to the display surface is provided outside the reflective display device, and the light emission amount of the front light is determined based on the detection result of the optical sensor. A method of adjusting can be considered. However, in this method, since the optical sensor is located outside the reflective display device, the size of the image display device is increased, and the proportion of light toward the display surface in the light incident on the optical sensor is reduced. End up. The latter contributes to the difficulty in accurately detecting the amount of light incident on the display surface.

  The present invention has been made in view of such circumstances, and solves the problem of providing an illumination device, an image display device, and an electronic apparatus that can accurately detect the amount of incident light without increasing the size of the device. It is an issue.

In order to solve this problem, the present invention is provided between a transparent first substrate, a transparent second substrate facing the first substrate, the first substrate and the second substrate, A light-emitting element that emits light toward the second substrate, and a light-detecting element that is provided between the first substrate and the second substrate and outputs a detection signal having a magnitude corresponding to the amount of light incident from the first substrate And a first light shielding layer that is formed on the second substrate and shields light incident from the second substrate toward the light detection element.
When illuminating an object with this illumination device, an object (object) to be illuminated is arranged on the second substrate side. Part of the external light that passes through the first substrate and travels toward the object enters the light detection element. Of the light emitted from the light emitting element, the light that is reflected by the object and travels toward the light detecting element is transmitted through the second substrate, but is blocked by the first light shielding layer.
According to this illumination device, since the light detection element is provided between the first substrate and the second substrate together with the light emitting element, it is not necessary to increase the device size, and the light detection element and the light emitting element are brought close to each other. Can be arranged. Usually, since the object is arranged near the light emitting element, by providing the light detection element close to the light emitting element, external light having the same amount of light as the external light incident on the object enters the light detection element. It will be. Further, according to this illumination device, the light shielding layer shields light incident from the second substrate toward the light detection element. Therefore, according to this illumination device, it is possible to accurately detect the amount of incident light.

  In the illumination device, the light emitting element includes a cathode and an anode, the light detection element includes a cathode and an anode, the light emitting element is formed on the second substrate, and the light detection element is the first detection element. It is formed on the light shielding layer, and the cathode of the light emitting element and the cathode of the light detecting element may be formed of the same material. This lighting device has an advantage that the cathode of the light emitting element and the cathode of the light detecting element can be formed by the same type of process (for example, vapor deposition using the same material). Furthermore, the cathode of the light detection element may be transparent, and the cathode may be disposed on the first substrate side. Further, the light emitting element is formed on the second substrate, and a second light shielding layer that shields light from the light emitting element is formed in a region on the first substrate corresponding to the light emitting element, and the second light shielding element is formed. A reflective material that reflects light from the light emitting element may be used on the surface of the layer facing the second substrate. According to this illumination device, most of the light emitted from the light emitting element can be directed to the second substrate.

  In each of the above lighting devices, the light emitting element is composed of an organic EL element, the organic EL element includes a hole injection layer, and the light detection element includes a P-type semiconductor layer, an N-type semiconductor layer, and the like. The hole injection layer and the P-type semiconductor layer may be formed of the same material. Further, in this lighting device, the cathode of the light emitting element and the cathode of the light detecting element may be formed by the same kind of process. Each of these lighting devices has an advantage that a layer (electrode) constituting a light emitting element and a layer (electrode) constituting a light detection element can be formed by the same type of process (for example, vapor deposition using the same material). There is. Further, the thicknesses of both layers may be equal to each other, and both layers may be formed simultaneously by the same process (one vapor deposition using the same material).

  In each of the illumination devices described above, the light detection element includes a plurality of photodiodes, the plurality of photodiodes are connected in series, the detection signal is given as a voltage, and the plurality of photodiodes connected in series is provided. The sum of the voltages output from the diode may be output to the outside as a light amount signal indicating a magnitude corresponding to the amount of light incident on the illumination device, and the light detection element is constituted by a plurality of photodiodes. The plurality of photodiodes are connected in parallel, the detection signal is given as a current, and the sum of the currents output from the plurality of photodiodes connected in parallel depends on the amount of light incident on the lighting device. Or a plurality of first detection lines and a plurality of second detection lines, and the light The output element may be composed of a plurality of photodiodes, and the plurality of photodiodes may be arranged corresponding to intersections of the plurality of first detection lines and the plurality of second detection lines, respectively. .

  In order to solve the above-described problems, the present invention provides an image display device comprising: each of the lighting devices described above; and a display device in which a display surface is in contact with the second substrate of the lighting device. provide. In this image display device, the display device may be a reflective liquid crystal device, and an adjustment unit that adjusts the light emission amount of the light emitting element based on the detection signal detected by the light detection element of the illumination device. You may make it provide, and may combine both.

  In order to solve the above problems, the present invention provides an illumination device including the first detection line and the second detection line, a first selection circuit that sequentially selects the plurality of first detection lines, Corresponding to an intersection of a second selection circuit that sequentially selects the plurality of second detection lines, a first detection line selected by the first selection circuit, and a second detection line selected by the second selection circuit Based on the detection signal output from the photodiode, a specifying unit that specifies a position where the object touches the first substrate of the lighting device, and a display in which the display surface is in contact with the second substrate of the lighting device An image display device comprising the device is provided.

  Moreover, in order to solve said subject, this invention provides the electronic device provided with each image display apparatus which has an illuminating device provided with said 1st detection line and 2nd detection line.

It is a figure which shows the structure of the image display apparatus 1 which concerns on 1st Embodiment of this invention. It is AA 'sectional drawing of FIG. It is sectional drawing which expands and shows a part of FIG. 3 is a plan view showing an arrangement of light emitting elements 211 and photodiodes 212 in the image display device 1. FIG. 3 is a circuit diagram showing an electrical connection relationship between a light emitting element 211 and a photodiode 212. FIG. It is a top view which shows arrangement | positioning of the photo-diode which concerns on the modification of 1st Embodiment. It is a figure which shows the structure of the image display apparatus 7 which concerns on 2nd Embodiment of this invention. 6 is a timing chart for explaining the operation of the image display device 7; It is a perspective view which shows the specific example of the electronic device which concerns on this invention. It is a perspective view which shows another specific example of the electronic device which concerns on this invention. It is a perspective view which shows another specific example of the electronic device which concerns on this invention.

  Embodiments of the present invention will be described with reference to the drawings. However, in each drawing, the ratio of the dimension of each part is appropriately different from the actual one. Further, the present invention is not limited to the embodiments described below, and various modifications obtained by modifying the embodiments, and forms obtained by applying the embodiments or modifications thereof. Can also be included in the technical scope. In addition, the same code | symbol is attached | subjected to the common part in each figure.

<First Embodiment>
FIG. 1 is a diagram showing a configuration of an image display device 1 according to the first embodiment of the present invention, and FIG. As shown in these drawings, the image display device 1 includes a reflective liquid crystal panel 101 having a plurality of liquid crystal elements LC arranged in a matrix. Each liquid crystal element LC has a liquid crystal and two electrodes for applying a voltage to the liquid crystal, and controls the light transmittance of the liquid crystal to display a gradation. The reflective liquid crystal panel 101 has a front surface. (Display surface FS) has a display area 102 for displaying an image represented by these gradations. Although not shown, the reflective liquid crystal panel 101 includes a plurality of scanning lines extending in the row direction and a plurality of data lines extending in the column direction. One liquid crystal element LC is provided at a position corresponding to each intersection of the scanning line and the data line.

  The image display device 1 also includes a scanning line driving circuit 103 that drives all scanning lines, a data line driving circuit 104 that drives all data lines, and a control circuit 105 that controls both circuits. Control of both circuits by the control circuit 105 supplies a control signal C1 including a clock signal to the scanning line driving circuit 103, and supplies a control signal C2 including a data signal corresponding to an image to be displayed to the data line driving circuit 104. Is done. The scanning line driving circuit 103 cyclically selects one scanning line at a time based on the control signal C1, and the data line driving circuit 104 selects one row corresponding to the selected scanning line based on the control signal C2. A signal for setting the light transmittance of the liquid crystal is supplied to each of the liquid crystal elements LC via a corresponding data line. By this scanning, an image to be displayed is displayed in the display area 102.

  As is clear from the above description, the reflective liquid crystal panel 101, the scanning line driving circuit 103, the data line driving circuit 104, and the control circuit 105 constitute a reflective display device that displays an image by controlling the light reflectance. ing. Note that at least one of the scanning line driving circuit 103, the data line driving circuit 104, and the control circuit 105 may be integrated with the reflective liquid crystal panel 101.

  The image display device 1 also includes a front light 106 bonded to the display surface FS of the reflective liquid crystal panel 101. The front light 106 includes a plurality of light emitting elements 211 that emit light with a light amount (luminance) corresponding to the supplied power signal C4, and illuminates the entire display area 102. The front light 106 includes a plurality of photodiodes 212 that output detection signals having a magnitude corresponding to the amount of incident light. A light amount signal DA obtained by synthesizing all the detection signals of the photodiodes 212 is supplied to the control circuit 105. Supply.

  Further, the image display device 1 includes a light control circuit 107. The control circuit 105 generates a control signal C3 for controlling the light emission amount of all the light emitting elements 211 based on the light amount signal DA from the light detection element of the front light 106, and supplies the control signal C3 to the dimming circuit 107. The dimming circuit 107 uniformly adjusts the light emission amounts of all the light emitting elements 211 based on the control signal C3. Power is supplied to the light control circuit 107, and the light control circuit 107 generates a power signal C <b> 4 having a potential corresponding to the control signal C <b> 3 using the power supply and supplies the power signal to each light emitting element 211. By this light control, the light emission amount of the light emitting element 211 becomes an amount corresponding to the amount of light incident on the photodiode 212.

  As is apparent from the above description, the control circuit 105 and the dimming circuit 107 constitute an adjusting unit that adjusts the light emission amount of the light emitting element 211. Further, the front light 106, the control circuit 105, and the dimming circuit 107 constitute an illumination device that illuminates the entire display area 102. One or both of the control circuit 105 and the dimming circuit 107 may be integrated with the front light 106.

  2 is a cross-sectional view taken along the line AA ′ of FIG. As shown in this figure, the front light 106 overlaps the reflective liquid crystal panel 101 in the region overlapping the display region 102. The reflective liquid crystal panel 101 includes a display substrate 201, a plurality of TFTs (thin film transistors) 202 formed on the display substrate 201, an insulating layer 203 formed on the display substrate 201 so as to cover the TFTs 202, and formed thereon. And a plurality of light-reflective pixel electrodes 204. The pixel electrode 204 is electrically connected to the corresponding TFT 202 through a contact hole formed in the insulating layer 203.

  The reflective liquid crystal panel 101 includes a liquid crystal 205 formed on the insulating layer 203 so as to cover the pixel electrode 204, a common electrode 206 formed on the liquid crystal 205, and a counter substrate 207 provided on the common electrode 206. A polarizing plate 208 formed over the counter substrate 207 and an adhesive layer 209 formed over the polarizing plate 208. One pixel electrode 204, a common electrode 206 overlapping the pixel electrode 204, and a liquid crystal 205 sandwiched between the two electrodes constitute one liquid crystal element LC. The light transmittance of the liquid crystal 205 is It changes according to the potential difference between the electrodes.

  The front light 106 includes a transparent lighting substrate (second substrate) 210 provided on the adhesive layer 209, a plurality of light emitting elements 211 formed on the lighting substrate 210, and a plurality of light emitting elements 211 formed on the lighting substrate 210. A photodiode 212, a transparent sealing substrate (first substrate) 214 provided to face the illumination substrate 210 to protect the light emitting element 211 and the photodiode 212 from outside air, moisture, and the like, and the illumination substrate 210 and the sealing A light shielding layer 213 formed between the stop substrate 214 and the light blocking layer 214. The illumination substrate 210 and the sealing substrate 214 are made of, for example, glass, and all the light emitting elements 211 and all the photodiodes 212 are provided therebetween.

  The light shielding layer 213 is provided for the purpose of blocking light from the light emitting element 211 toward the sealing substrate 214 and blocking light (reflected light) from the illumination substrate 210 toward the photodiode 212. It is interposed between the substrate 214 and between each photodiode 212 and the illumination substrate 210. Therefore, the light emitting element 211 emits light toward the illumination substrate 210, and most of the light incident on the photodiode 212 is external light transmitted through the sealing substrate 214. Therefore, the amount of external light incident on the photodiode 212 is the same as the amount of external light incident on the liquid crystal element LC in the vicinity of the photodiode 212, and the detection signal of the photodiode 212 enters the liquid crystal element LC in the vicinity. The signal corresponds to the amount of external light. Therefore, the photodiode 212 outputs a detection signal having a magnitude corresponding to the amount of light incident from the sealing substrate 214.

  As the light shielding layer 213, a layer that does not reflect external light incident from the sealing substrate 214 is preferable. The light shielding layer 213 is formed using a material according to this situation and the above-described purpose. A metal thin film having a low light reflectance such as chromium, chromium oxide, a laminated film of chromium and chromium oxide, or a resin material having a low light transmittance is preferable. Note that the formation material may be different between the light-blocking layer 213 that overlaps with the light-emitting element 211 and the light-blocking layer 213 that overlaps with the photodiode 212.

  Note that light emitted from the light emitting element 211 includes light traveling toward each liquid crystal element LC, and the light passes through the illumination substrate 210 and enters each liquid crystal element LC. Further, external light from the sealing substrate 214 toward the liquid crystal element LC enters the liquid crystal element LC. The reflected light of the liquid crystal element LC (pixel electrode 204) includes the reflected light of the outside light and the reflected light of the light emitted from each light emitting element 211 and incident on the liquid crystal element LC.

  FIG. 3 is an enlarged cross-sectional view of a part of FIG. The light emitting element 211 is an organic EL element. As shown in this figure, the anode 301 formed of ITO on the illumination substrate 210, the hole injection layer 302 formed thereon, and the anode injection layer 302 are formed thereon. Hole transport layer 303, light emitting layer 304 formed thereon, electron transport layer 305 formed thereon, electron injection layer 306 formed thereon, and cathode formed thereon 307. A power supply signal C4 is supplied to the anode 301.

  The hole injection layer 302 is a copper phthalocyanine thin film having a thickness of about 30 nm. The hole transport layer 303 is an NPD thin film, for example, and the film thickness is about 20 nm. The light emitting layer 304 is a thin film of a low molecular white light emitting material, for example, and the film thickness is about 20 nm. The electron transport layer 305 is, for example, a thin film of aluminum quinolinol complex (tris (8-hydroxyquinoline) aluminum), and the film thickness is about 30 nm. The electron injection layer 306 is, for example, a lithium fluoride thin film, and the film thickness is about 1 nm. The cathode 307 is an aluminum thin film having a thickness of about 150 nm.

  The photodiode 212 is an organic photodiode. As shown in this figure, an anode 308 formed of ITO on a light shielding layer 213 formed on the illumination substrate 210 and a P-type semiconductor layer formed thereon. 309, an N-type semiconductor layer 310 formed thereon, and a cathode 312 formed thereon. The P-type semiconductor layer 309 is a copper phthalocyanine thin film having a thickness of about 30 nm. The N-type semiconductor layer 310 is a PTCDI (3,4,9,10-perylene-tetracarboxylic-diimide) thin film, and the film thickness is about 50 nm. The cathode 312 is made of a transparent material with high light transmittance.

  As is apparent from the above, the hole injection layer 302 and the P-type semiconductor layer 309 can be formed by mask vapor deposition using the same material (copper phthalocyanine), that is, the same process. This is an advantage that contributes to the simplification of the manufacturing process, and also applies to the anode 301 and the anode 308. Further, since the thickness of the hole injection layer 302 is equal to the thickness of the P-type semiconductor layer 309, the hole injection layer 302 and the P-type semiconductor layer 309 are formed in the same process (one deposition using the same material). ) Can be formed simultaneously. This also applies to the cathode 307 and the cathode 312. Note that the cathode 307 may be formed of the same transparent material as that of the cathode 312, and the thicknesses of the two may be made equal to each other. In this case, it is preferable to use a reflective material that reflects light from the light emitting element 211 on the surface of the light shielding layer 213 that overlaps with the light emitting element 211 (second light shielding layer) and faces the illumination substrate 210. By doing so, the light emitted from the light emitting element 211 and traveling toward the sealing substrate 214 is reflected by the reflecting material and travels toward the illumination substrate 210, so that most of the light emission of the light emitting element 211 can be directed to the illumination substrate 210. .

  Of course, the above-described forming materials and film thicknesses are only examples. For example, the formation material of the cathode 312 may be gold or aluminum, the formation material of the P-type semiconductor layer 309 may be rubrene, and the film thickness of the P-type semiconductor layer 309 or the N-type semiconductor layer 310 may be changed. . Further, for example, at least one of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer may be deleted from the light emitting element 212. In any case, if a layer formed of the same material is included in the light-emitting element 211 and the photodiode 212, the layer included in the light-emitting element 211 and the layer included in the photodiode 212 are the same type. It can be formed by a process, and if both layers have the same film thickness, they can be formed all at once by the same process.

  FIG. 4 is a plan view showing the arrangement of the light emitting elements 211 and the photodiodes 212 in the image display device 1. In this figure, four power supply wires (anode wires 401 and 403 and cathode wires 402 and 404) provided between the illumination substrate 210 and the sealing substrate 214 are viewed from the sealing substrate 214 side. .

  The anode wiring 401 is a comb-like wiring including the anodes 301 of all the light emitting elements 211, and supplies the power supply signal C <b> 4 (high potential) from the dimming circuit 107 to each anode 301. The cathode wiring 402 is a comb-shaped wiring that is in contact with the cathodes 307 of all the light emitting elements 211, and supplies a ground potential (low potential) to each cathode 307. The anode wiring 401 and the cathode wiring 402 are arranged on the illumination substrate 210 so that comb teeth are alternately meshed, and a plurality of light emitting elements 211 correspond to each tooth.

  The anode wiring 403 is a comb-like wiring including the anodes 308 of all the photodiodes 212, and connects each anode 308 and the control circuit 105. The cathode wiring 404 is a comb-shaped wiring in contact with the cathodes 312 of all the photodiodes 212 and supplies a ground potential (low potential) to each cathode 312. The anode wiring 403 and the cathode wiring 404 are arranged on the illumination substrate 210 so that the comb teeth are alternately meshed, and a plurality of photodiodes 212 correspond to each tooth. As is clear from FIG. 4, the anode wiring 401 does not overlap the cathode wiring 402 or the cathode wiring 404, and the anode wiring 403 does not overlap the cathode wiring 402 or the cathode wiring 404. That is, the anode wiring and the cathode wiring do not overlap each other. This is an advantage that contributes to simplification of the manufacturing process.

  FIG. 5 is a circuit diagram showing an electrical connection relationship between the light emitting element 211 and the photodiode 212. The electrical connection relationship between the two will be described with reference to this figure. Here, in order to facilitate understanding, the electrode and the wiring are handled separately. As shown in the figure, all the anodes 301 are connected to the anode wiring 401, all the cathodes 307 are connected to the cathode wiring 402, all the anodes 308 are connected to the anode wiring 403, and all the cathodes 312 are connected to the cathode wiring 404. Connected. That is, all the light emitting elements 211 are connected in parallel between the anode wiring 401 and the cathode wiring 402 and function as one light emitting element, and all the photodiodes 212 are connected between the anode wiring 403 and the cathode wiring 404. It is connected in parallel and functions as one photodetecting element.

  The output current of the light detection element is supplied to the control circuit 105 as a light quantity signal DA. The control circuit 105 generates a control signal C3 based on the light amount signal DA. This generation method is arbitrary. For example, the control signal C3 may be generated based on the difference between the value indicated by the light amount signal DA and the value corresponding to the light amount of the illumination light of the front light 106, or the control signal C3 based only on the light amount signal DA. May be generated.

  FIG. 6 is a plan view showing the arrangement of photodiodes according to a modification of the present embodiment. The image display apparatus according to this figure includes a cathode wiring 601 instead of the cathode wiring 404. The cathode wiring 601 is a comb-like wiring, and the cathode wiring 601 and the anode wiring 403 are arranged on the illumination substrate 210 so that the comb teeth are alternately meshed. Further, the tips of the teeth of the cathode wiring 601 are bent along the roots of the teeth of the anode wiring 403. The photodiode included in the image display device, that is, the photodiode constituting the light detection element is only one photodiode 602. The photodiode 602 is formed in a comb-like region on the anode wiring 403, and this region is covered with a cathode 603 that is in contact with the cathode wiring 601. In this image display device, a current flowing through the photodiode 602 is supplied to the control circuit 105 as a light amount signal DA. As is apparent from FIG. 6, the anode wiring 403 and the cathode wiring 601 do not overlap each other. This is an advantage that contributes to simplification of the manufacturing process.

  As described above, the image display device 1 is provided with the transparent illumination substrate 210, the transparent sealing substrate 214 facing the illumination substrate 210, and the illumination substrate 210 and the sealing substrate 214. A light-emitting element 211 that emits light toward 210, a light-detecting element that is provided between the illumination substrate 210 and the sealing substrate 214, and that outputs a detection signal having a magnitude corresponding to the amount of light incident from the sealing substrate 214; A light shielding layer 213 that is formed on the illumination substrate 210 and shields light incident from the illumination substrate 210 toward the light detection element. Further, in the image display device 1, the photodiode 212 constituting the light emitting element is provided close to each other between the illumination substrate 210 and the sealing substrate 214 together with the light emitting element 211. By adopting such a configuration, it is not necessary to increase the device size, and there is also an advantage that external light having the same amount of light as the external light incident on the reflective liquid crystal panel 101 is incident on the photodetecting element. In addition, in the image display device 1, the light shielding layer 213 shields light incident from the illumination substrate 210 toward the photodiode 212. Therefore, according to the image display device 1, the amount of light incident on the object can be accurately detected.

  In the above-described embodiment, the plurality of photodiodes 212 constituting the light detection element are connected in parallel, the detection signal is given as a current, and the sum of the currents output from these photodiodes 212 is the light quantity signal. DA is output to the outside of the front light 106, but this is modified, and a plurality of photodiodes 212 constituting a light detection element are connected in series, and a detection signal is given as a voltage. The total sum of the voltages output from may be output to the outside of the front light 106 as the light amount signal DA.

  Further, by modifying the above-described embodiment, the front light 106 includes a plurality of first detection lines and a plurality of second detection lines, and the plurality of photodiodes 212 constituting the light detection element include a plurality of first detection lines. You may make it each arrange | position corresponding to the intersection of a detection line and several 2nd detection line. In this case, the control circuit 105 generates the control signal C3 based on the detection values of the m × n photodiodes 212 indicated by the light amount signal DA. As a preferable method of this generation, there is a method of calculating an average value or median value of these detection values and generating the control signal C3 based on the calculation result.

<Second Embodiment>
FIG. 7 is a diagram showing a configuration of an image display device 7 according to the second embodiment of the present invention, and FIG. 8 is a timing chart for explaining the operation thereof. The image display device 7 is a device that can specify a position touched by an object Z such as a finger or a pen, and includes a control circuit 701 instead of the control circuit 105 and a front light 702 instead of the front light 106.

  The control circuit 701 is significantly different from the control circuit 105 in that a signal DB is supplied instead of the light amount signal DA, and control signals C5 and C6 for causing each photodiode to output a detection signal are generated and output. Is a point. The front light 702 includes m × n photodiodes 212. These photodiodes 212 are arranged corresponding to the intersections of the m first detection lines 703 and the n second detection lines 704, respectively. The anode 308 of each photodiode 212 is electrically connected to the corresponding second detection line 704, and the cathode 312 is electrically connected to the corresponding first detection line 703. Note that an insulating layer is interposed between the layer of the first detection line 703 and the layer of the second detection line 704 at a portion where the first detection line 703 and the second detection line 704 intersect.

  In addition, the image display device 7 includes m first detection lines 703 extending in the row direction, n second detection lines 704 extending in the column direction, and m first detection lines based on the control signal C5. A Y driver (first selection circuit) 705 that sequentially selects the detection lines 703 and an X driver (second selection circuit) 706 that sequentially selects n second detection lines 704 based on the control signal C6 are provided. The control signal C5 includes a clock signal having a cycle of 1Y and a row selection pulse for sequentially selecting the m first detection lines 703. The m cycle of the clock signal is one cycle of the row selection pulse, and the row selection pulse becomes an active level in one cycle of the m cycles. The control signal C6 includes a clock signal having a cycle of 1X and a column selection pulse for sequentially selecting the n second detection lines 704. 1X = 1Y / n. The n cycle of the clock signal is one cycle of the row selection pulse, and the column selection pulse is at the active level in one cycle of the n cycles.

  The Y driver 705 is provided corresponding to each of the m-stage shift register 707 to which the control signal C5 is supplied and the m first detection lines 703, and each of the corresponding first detection lines 703 and the ground potential (cathode). M switches 708 connecting the wiring 402). The shift register 707 shifts every row selection period (1Y) based on a clock signal, and a row selection pulse is input to the first stage. Each stage of the shift register 707 has a one-to-one correspondence with each first detection line 703, and each switch 708 is turned on / off based on the row selection signals Y1 to Ym from the corresponding stage.

  The row selection signals Y1 to Ym are signals for sequentially selecting the m first detection lines 703. As shown in FIG. 8, only the row selection signal Y1 is active in the first row selection period (1Y). In the second row selection period, only the row selection signal Y2 is active level,..., Only the row selection signal Ym is in the active level in the mth row selection period, and the row selection signal Y1 in the m + 1th row selection period. Only becomes the active level. Therefore, the m first detection lines 703 in FIG. 7 are selected alternatively and cyclically by turning on / off the m switches 708.

  The X driver 706 is provided corresponding to the n-stage shift register 709 to which the control signal C6 is supplied, the amplifier 711 that amplifies and outputs the input signal, and the n second detection lines 704, respectively. It has n switches 710 that connect the corresponding second detection lines 704 and the input ends of the amplifier 711, and a sample and hold circuit 712 that operates based on a clock signal. The shift register 709 performs a shift every column selection period (1X) based on a clock signal, and a column selection pulse is input to the first stage. Each stage of the shift register 709 has a one-to-one correspondence with each second detection line 704, and each switch 710 is turned on / off based on column selection signals X1 to Xm from the corresponding stage.

  The column selection signals X1 to Xn are signals for sequentially selecting the n second detection lines 704. As shown in FIG. 8, only the column selection signal X1 is active in the first column selection period (1X). In the second column selection period, only the column selection signal X2 becomes active level,..., Only the column selection signal Xn becomes active level in the nth column selection period, and the column selection signal X1 in the n + 1th column selection period. Only becomes the active level. Therefore, the n second detection lines 704 in FIG. 7 are selected alternatively and cyclically by turning on / off the n switches 710. Further, as described above, 1X = 1Y / n. Therefore, the n second detection lines 704 are sequentially selected by turning on / off the n switches 710 in each row selection period (1Y).

  In this way, m × n photodiodes 212 are sequentially selected. In the selected photodiode 212, a ground potential is supplied to the cathode 312 and the anode 308 is electrically connected to the input terminal of the amplifier 711. Therefore, a current having a magnitude corresponding to the amount of incident light is supplied to the amplifier 711. To supply. When the currents flowing through the m second detection lines 704 are the detection signals d1 to dn, respectively, the second detection line 704 electrically connected to the input terminal of the amplifier 711 is switched every column selection period. As shown in FIG. 8, the amplifier 711 is supplied with a signal d in which the detection signals d1 to dn are arranged for each column selection period.

  The signal d is amplified by the amplifier 711 and supplied to the sample and hold circuit 712. The sample hold circuit 712 has a capacitive element, accumulates electric charge corresponding to the signal d in the capacitive element, samples the voltage held in the capacitive element every sampling period (T), and finally samples. The signal DB indicating the measured voltage is continuously output. Although T = 1X, sampling is performed at times t1, t2,... Immediately before the end of the column selection period in order to perform sampling after the holding voltage of the capacitive element is stabilized. It is prescribed as follows. The X driver 706 may be provided with an A / D converter, and the output signal of the sample hold circuit 712 may be A / D converted as the signal DB.

  The control circuit 701 functions as a specifying unit that specifies the position where the object Z touches the sealing substrate 214 based on the signal DB. This particular method is arbitrary. For example, the signal DB is binarized (bited) in comparison with a predetermined threshold value, and one or a plurality of positions are specified as the contact position of the object based on a bit pattern over a matrix of m rows and n columns. It may be. Note that the present embodiment may be modified so that the control circuit 701 detects the presence or absence of contact with an object instead of the contact position of the object.

  Note that, similarly to the control circuit 105, the control circuit 701 generates a control signal C3 for controlling the light emission amounts of all the light emitting elements 211. However, in the present embodiment, the average value of the detection values of the m × n photodiodes 212 indicated by the signal DB is calculated, and the control signal C3 is generated based on the calculation result. Of course, this may be modified to calculate the median of the detection values of the m × n photodiodes 212 indicated by the signal DB, and the control signal C3 may be generated based on the calculation result. Further, the light emission amount of each light emitting element 211 may not be controlled. In this case, the generation of the control signal C3 becomes unnecessary, and a fixed power source can be used in place of the dimming circuit 107.

<Other variations>
In each of the above-described embodiments, the anode 301 of the light emitting element 211 and the anode 308 of the photodiode 212 are formed of the same material, but they may be formed of different materials. This also applies between the hole injection layer 302 of the light emitting element 211 and the P-type semiconductor layer 309 of the photodiode 212, and also applies between the cathode 307 of the light emitting element 211 and the cathode 312 of the photodiode 212.

  Moreover, in each embodiment mentioned above, although the object which a illuminating device illuminates is limited to a reflection type liquid crystal device, this may be deform | transformed and an illuminating device may illuminate another target object. Examples of other objects include a reflective display device other than the reflective liquid crystal display device, an instrument such as an analog meter that indicates a numerical value with a needle, and a post such as a paper poster. Further, as the liquid crystal element, a liquid crystal element other than a liquid crystal element in which a voltage is applied in the thickness direction of the liquid crystal (a liquid crystal element in which a voltage is applied in a direction different from the direction) may be employed. Moreover, you may employ | adopt light emitting elements (for example, LED (Light Emitting Diode) and LD (Laser Diode)) other than an organic EL element as a light emitting element. Alternatively, the cathode 310 may be formed using an opaque material with low light transmittance as long as the cathode 310 does not have to be disposed on the sealing substrate 214 side.

<Application example>
Next, an electronic apparatus using the display device according to the present invention will be described. In this description, an image display device according to an embodiment of the present invention or a modification thereof is referred to as “image display device 8”. FIG. 9 is a perspective view showing a configuration of a mobile personal computer adopting the image display device 8 as a display unit. The personal computer 2000 includes an image display device 8 as a display unit and a main body 2010. The main body 2010 is provided with a power switch 2001 and a keyboard 2002.
FIG. 10 shows a configuration of a mobile phone to which the image display device 8 is applied. The cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and an image display device 8 as a display unit. By operating the scroll button 3002, the screen displayed on the image display device 8 is scrolled.
FIG. 11 shows a configuration of a personal digital assistant (PDA) to which the image display device 8 is applied. The portable information terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and an image display device 8 as a display unit.
The electronic apparatus to which the image display device according to the present invention is applied includes, in addition to those shown in FIGS. 9 to 11, a television, a digital still camera, a video camera, a car navigation device, an electronic notebook, electronic paper, a calculator, Examples include word processors, workstations, videophones, copiers, and video players.

DESCRIPTION OF SYMBOLS 1,7 ... Image display apparatus, 101 ... Reflective type liquid crystal panel, 105,701 ... Control circuit, 106,702 ... Front light, 107 ... Dimming circuit, 210 ... Lighting board (second board) , 211... Light emitting element, 212, 602... Photodiode, 213... Light shielding layer, 214... Sealing substrate (first substrate), 301, 308. 312, 603... Cathode, 309... P-type semiconductor layer, 703... First detection line, 704... Second detection line, 705... Y driver, 706. Equipment), 3000 ... cellular phone (electronic equipment), 4000 ... portable information terminal (electronic equipment), d1 to dn ... detection signal, DA ... light quantity signal, FS ... display surface.

Claims (13)

A transparent first substrate;
A transparent second substrate facing the first substrate;
A light emitting element provided between the first substrate and the second substrate and emitting light toward the second substrate;
A photodetecting element that is provided between the first substrate and the second substrate and outputs a detection signal having a magnitude corresponding to the amount of light incident from the first substrate;
A first light shielding layer that is formed on the second substrate and shields light incident from the second substrate toward the light detection element;
A lighting device comprising: The light emitting device includes a cathode and an anode,
The photodetecting element comprises a cathode and an anode,
The light emitting device is formed on the second substrate;
The photodetecting element is formed on the first light shielding layer,
The cathode of the light emitting element and the cathode of the light detection element are formed of the same material.
The lighting device according to claim 1.   The lighting device according to claim 2, wherein a cathode of the light detection element is transparent. The light emitting device is formed on the second substrate;
A second light shielding layer for shielding light from the light emitting element is formed in a region on the first substrate corresponding to the light emitting element;
A reflective material that reflects light from the light emitting element is used on a surface of the second light shielding layer that faces the second substrate.
The lighting device according to claim 3. The light emitting element is composed of an organic EL element,
The organic EL element includes a hole injection layer,
The photodetecting element includes a P-type semiconductor layer and an N-type semiconductor layer,
The hole injection layer and the P-type semiconductor layer are formed of the same material.
The lighting device according to claim 2, wherein the lighting device is a light source. The photodetecting element is composed of a plurality of photodiodes,
The plurality of photodiodes are connected in series,
The detection signal is given as a voltage;
The sum of the voltages output from the plurality of photodiodes connected in series is output to the outside as a light amount signal indicating a magnitude corresponding to the amount of light incident on the illumination device.
The lighting device according to any one of claims 1 to 5, wherein: The photodetecting element is composed of a plurality of photodiodes,
The plurality of photodiodes are connected in parallel,
The detection signal is given as a current,
The total sum of currents output from the plurality of photodiodes connected in parallel is output to the outside as a light amount signal indicating a magnitude corresponding to the amount of light incident on the illumination device.
The lighting device according to any one of claims 1 to 5, wherein: A plurality of first detection lines;
A plurality of second detection lines,
The photodetecting element is composed of a plurality of photodiodes,
The plurality of photodiodes are respectively arranged corresponding to intersections of the plurality of first detection lines and the plurality of second detection lines.
The lighting device according to any one of claims 1 to 5, wherein: The lighting device according to any one of claims 1 to 8,
A display device having a display surface in contact with the second substrate of the illumination device;
An image display device comprising:   The image display device according to claim 9, wherein the display device is a reflective liquid crystal device.   The image display device according to claim 9, further comprising an adjusting unit that adjusts a light emission amount of the light emitting element based on the detection signal detected by the light detection element of the illumination device. A lighting device according to claim 8;
A first selection circuit for sequentially selecting the plurality of first detection lines;
A second selection circuit for sequentially selecting the plurality of second detection lines;
The illumination based on the detection signal output from the photodiode corresponding to the intersection of the first detection line selected by the first selection circuit and the second detection line selected by the second selection circuit. Specifying means for specifying a position where an object touches the first substrate of the apparatus;
A display device having a display surface in contact with the second substrate of the illumination device;
An image display device comprising: An electronic apparatus comprising the image display device according to claim 9.

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